WO2006114685A1

WO2006114685A1 - Continuous fluid flow irrigation system

Info

Publication number: WO2006114685A1
Application number: PCT/IB2006/000995
Authority: WO
Inventors: Atul Kumar; Alka Kumar
Original assignee: Atul Kumar; Alka Kumar
Priority date: 2005-04-25
Filing date: 2006-04-25
Publication date: 2006-11-02

Abstract

The present invention provides continuous fluid flow irrigation system for transporting flui across an industrial cavity under substantially constant pressure and reduced turbulence suc that the cavity pressure and the cavity fluid flow rate are absolutely independent of each othe without incorporating any type of controller. The present invention also provides a system t dampen the pressure pulsations created by positive displacement pumps in an active manne without utilizing any feedback mechanism.

Description

CONTINUOUS FLUID FLOW IRRIGATION SYSTEM

FIELD OF INVENTION: The present invention is related to the field of fluid mechanics and it is useful in multiple industrial applications. The present invention provides a system of transporting valuable fluids such as petroleum, water, natural gas through pipes over long distances at constant pressure and reduced turbulence. The present invention also provides a system for pressurizing industrial cavities harboring chemical reactions or feed chamber cavity in membrane filtration systems.

BACKGROUND AND PRIOR ART DESCRIPTION:

Valuable fluids such as water, petroleum and gas are continuously transported over long distances through long pipes. There are many prior art systems which are used for transporting fluids through pipes whose length may vary from a few meters to a few hundred kilometers. All such systems deploy pumps as the source of energy. One or more of said pumps are usually installed over the inflow side of the pipe or over the outflow end of the pipe or over both inlet and outlet ends of the said pipe. Hence forth the system comprising of the pipe along with one or more pumps shall be referred to as 'pumping unit'. The pumps deployed with the 'pumping unit' can be categorized into two broad categories, 'dynamic pumps' and 'positive displacement pumps'. Dynamic pumps comprise pumps like centrifugal pumps, while positive displacement pumps comprise pumps such as piston pumps, membrane pumps, plunger pumps, gear pumps. The known methods / systems of installing pumps on a pipe are given in Table 1: Table 1: Conventional methods /systems of installing pumps in a 'pumping unit'

In the same manner, all the above-mentioned methods are also used for pressurizing industrial cavities like the feed chamber cavity in membrane systems such as reverse osmosis systems, a cavity housing chemical reactions etc.

In the present invention the inventors have concentrated upon the system which is mentioned in serial No. 8. Although, positive displacement pumps have obvious advantages over dynamic pumps and they are generally considered to be more efficient in comparison to dynamic pumps, the system described in serial number eight in table 1 (i.e. placing a positive displacement pump on both the inlet and outlet ends having identical flow rates), is seldom used alone for transporting fluids over a long distance for a longer duration of time or for pressuring industrial cavities. By the term "used alone" we mean to state that the system is not manipulated or managed or under the surveillance of a human being or a controller or a feed back system or any other functionally similar systems.

The reasons behind not using the arrangement mentioned in serial No. 8 as such for transporting fluid over long distances for a longer duration of time or for pressuring industrial cavities are described in brief in the following paragraph:

1. Build up / reduction of pressure over a longer period of time: It has been found that the said system is not practically feasible since when the two positive displacement pumps work simultaneously at constant RPM over a longer period of time, it results in either build up of pressure inside the pipe or the industrial cavity or drop in the pressure inside the pipe or the industrial cavity. The reason for the same being no two positive displacement pump's have absolutely identical flow rates. The flow rate of a positive displacement pump is a linear function of the pump RPM. Even if the said positive displacement pumps are designed in the most efficient manner, during operation, their RPM's cannot be maintained absolutely identical. Thus, even if the difference in the RPM's of the two pumps is infinitely small, over a period of time, it results in either build up of pressure inside the pipe or the industrial cavity or drop in the pressure inside the pipe or the industrial cavity. It has been noticed that were the two identical positive displacement pumps are attached to the two ends of the pipe or the industrial cavity and are operated simultaneously at fixed flow rates, in order to transport fluid through the pipe or the industrial cavity, there exists a small mismatch between the RPM of the two pumps. If the RPM of the inflow pump is minutely greater than the RPM of the outflow pump, then some extra fluid shall continuously accumulate inside the pipe or the cavity and over a period of time an infinitely high pressure shall develop inside the pipe cavity and the pipe or the cavity shall burst.

Vice versa, if the RPM of the inflow pump is minutely lesser than the RPM of the outflow pump, then some fluid shall continuously be depleted from the pipe or the cavity and over a period of time and infinitely low vacuum pressure shall develop inside the pipe or the cavity and the same shall collapse. 2. Nature of the fluid being pumped by positive displacement pump: Since the positive displacement pump pumps or withdraws the fluid in a pulsatile manner, the buildup or the reduction of the pressure inside the pipe or the cavity is aggravated. The pulsatile nature of the positive displacement pump creates turbulence, which in many situations could be undesirable and which may lead to the early deterioration of the pipes or the cavity (by way of example, it may lead to early rupture of the pipes or the cavity when the RPM of the inflow pump is minutely greater than the RPM of the outflow pump).

Positive displacement pumps are extensively used in multiple industrial applications however their major disadvantage is that they have a pulsatile flow. All positive displacement pumps work in a reciprocating manner and that is the reason why they pump or suck fluid in a pulsatile manner and the resultant fluid flow is characterized by inherent 'pressure pulsations' whose frequency is linearly related to the pump RPM and the amplitude is a parabolic like function of the pump pressure. The said pressure pulsations cause mechanical wear and tear of the components of a pumping unit such as the pump, pipes, valves and pressure sensors. The 'pressure pulsations' may also decrease the efficiency of the pumping unit.

In order to avoid build up / reduction of pressure over a longer period of time in the pipe or the cavity, a pressure sensor and a controller is included in the system. The pressure sensor senses the pressure insider the pipe or the cavity and outputs its value to the controller and if the controller determines that the pressure to be increasing or decreasing beyond a certain level, it varies the operation of either of the inflow pump or the outflow pump to avoid such build up / reduction of pressure over a longer period of time in the pipe or the cavity. The same problem could be solved by a continuous human intervention by an operator, may be in a less efficient manner. Although this solution avoids build up / reduction of pressure over a longer period of time in the pipe or the industrial cavity, it does not address the problem of turbulence created inside the pipe or the cavity due to the pulsatile nature of the positive displacement pump or otherwise.

In the prior art, in order to counteract problem of turbulence created inside the pipe or the cavity, a separate pressure dampening compression chamber is incorporated in the system. In the prior art systems pressure pulsations are dampened by incorporating a passively working fixed volume expansion chamber. Those conversant with the system of the prior art would understand the disadvantages of such passively working conventional pressure dampening systems. The said 'expansion chamber' is a chamber having a fixed volume capacity and is filled either with a gas or a compressible fluid. The 'expansion chamber' has only one opening which is connected to the irrigation circuit of the pumping unit at any suitable location. The said compressible fluid contained inside the 'expansion chamber' may also be contained inside an elastic bladder in order to avoid the compressible fluid from coming in contact with the fluid or gas flowing in the irrigation circuit of the pumping unit. If a positive pressure fluctuation occurs inside the irrigation circuit the contents of the said bladder are compressed thus minimizing the amplitude of the positive pressure fluctuation. Similarly, if a negative pressure fluctuation occurs inside the irrigation circuit the contents of the bladder expand thereby minimizing the amplitude of the corresponding negative pressure fluctuation. However, even theoretically, no expansion chamber can achieve 100% dampening of the pressure pulsations. In order to achieve a relatively high working efficiency in the conventional expansion chambers a considerable amount of engineering skill and complicated feedback mechanisms are often deployed. The pressure inside the said bladder of the expansion chamber is maintained only slightly lower, depending upon the technical requirement; say 10 % to 20% lower than the pressure in the irrigation circuit. If the pressure inside the bladder decreases significantly below the pressure in the irrigation circuit the efficiency of the pressure dampening efficiency of the expansion chamber decreases. If the pressure inside the expansion chamber rises above the pressure in the irrigation circuit the expansion chamber the pressure dampening function all together ceases. The pressure dampening compression chamber provides passive correction of the turbulence created inside the pipe or the cavity. However, it is most efficient to dampen the turbulence created by means other than the working of the positive displacement pump and it does not efficiently provide any relief against the turbulence created by the working of the positive displacement pumps. The problems with the above-mentioned system are that they are quiet costly, complex and not user friendly. Further, the dampening efficiency is related to a specific pressure or range. Thus there is a need to provide an improved system which addresses at least some the drawbacks existing in the prior art system. OBJECTS OF THE INVENTION An objective of the invention is to provide a system for long distance fluid transportation, which is different and more efficient than the prior art systems.

Another objective of the present invention is to provide a system for pressuring industrial cavities. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a layout of the invention along with the 'pressure pulse dampening system' and a controller.

Figure 2 is similar to figure 1 except that the 'pressure pulse dampening system' has not been included.

Figure 3 is similar to figure 2 except that the controller has not been included.

Figure 4 shows the inflow part of the system along with the inflow peristaltic pump 5, the pressure transducer 17 and the constriction site 8.

Figure 5 is similar to figure 3 except that in this figure a shaded region represents an area having an almost similar uniform pressure.

Figure 6 is similar to figure 3 except that an optional constriction housing tube 17, an optional pressure transducer 63 and a pressure transducer 73 attached directly to the cavity have been included.

Figure 7 shows is the schematic diagram for pump synchronization on a common rotor shaft. Figure 8 shows the basic lay out of the syringe mechanism based 'pressure pulse dampening system'.

Figure 9 shows a detailed layout of the syringe mechanism along with a coupling means.

Figure 10 is similar to figure except that a cross flow reverse osmosis unit has also been included. DETAILED DESCRIPTION OF THE INVENTION:

Accordingly, the present invention provides a continuous fluid flow irrigation system for transporting fluid across an industrial cavity under substantially constant pressure and reduced turbulence, said system comprising: a fluid source reservoir containing a fluid meant for being transported across the industrial cavity; a fluid supply conduit tube connecting the fluid source reservoir to an inlet end of a positive displacement inflow pump and an outlet end of the said inflow pump being connectable to an inflow port of the industrial cavity for pumping the fluid at a controlled flow rate into the industrial cavity, the flow rate of the inflow pump being termed as the inflow rate; an outflow port of the industrial cavity being connectable to an inlet end of a positive displacement outflow pump for removing the fluid from the industrial cavity at a controlled flow rate, the flow rate of the outflow pump being termed as the outflow rate, and a housing tube having a controllable constriction site is being provided between an inflow region and the inflow port of the industrial cavity, the inflow region comprising of the fluid source reservoir, the fluid supply conduit tube and the atmosphere; such that the housing tube by-passes the inflow pump and provides a route for any excess fluid present in the industrial cavity to bypass the inflow pump and go back to the inflow region when the inflow and the outflow pumps are operated at substantially fixed flow rates thereby maintaining the pressure inside the industrial cavity at a stable value and minimizing turbulence inside the industrial cavity.

In an embodiment of the present invention, the fluid source reservoir containing the fluid is maintained at atmospheric pressure or at a pressure greater than the atmospheric pressure or at a pressure lower than the atmospheric pressure. In another embodiment of the present invention, a proximal open end of the fluid supply conduit tube is connected to the fluid source reservoir and a distal end of the tube is connected to the inlet end of positive displacement inflow pump.

In yet another embodiment of the present invention, the proximal open end of the fluid supply tube is constantly and completely immersed in the fluid source reservoir. In still another embodiment of the present invention, an outlet end of the inflow pump is connectable to the inflow port of the industrial cavity through an inflow tube.

In one more embodiment of the present invention, the positive displacement inflow pump is selected from the group comprising peristaltic pump, piston pump, gear pump, diaphragm pump and plunger pump. In one another embodiment of the present invention, the positive displacement inflow pump is a fixed flow rate pump, whose flow rate could be varied from one fixed flow rate value to another fixed flow rate value, or a variable flow rate pump and the same is a peristaltic pump.

In an embodiment of the present invention, the housing tube is releasably provided between the inflow region and the inflow port of the industrial cavity to enable replacement of the housing tube with yet another housing tube having a different diameter at the constriction site to suit the operational need of the industrial process.

In another embodiment of the present invention, a proximal end of the housing tube is connected to the fluid supply conduit tube near its distal end close to the inlet port of the inflow pump. In yet another embodiment of the present invention, the proximal end of the housing tube empties directly into the fluid source reservoir and is constantly and completely immersed in the fluid source reservoir.

In still another embodiment of the present invention, the proximal end of the housing tube opens into the atmosphere. In one more embodiment of the present invention, a distal end of the housing tube is connected to the inflow port of the industrial cavity or to the inflow tube near its proximal end close to the outlet end of the inflow pump.

In one another embodiment of the present invention, the housing tube is provided with a clamping means at the constriction site to enable the user to vary the diameter of the housing tube at the constriction site to suit the operational needs of an industrial process. In a further embodiment of the present invention, an inflow pressure transducer is located anywhere in the inflow tube between the outlet end of the inflow pump and the inflow port of the industrial cavity or is connected directly to the inflow port of the industrial cavity or is connected directly to the industrial cavity.

In a further more embodiment of the present invention, the inflow pressure transducer is located sufficiently away from the cavity site, near the outlet end of the inflow pump from the practical point of view, such that the fluid pressure measured by the same is almost equal to the fluid pressure inside the cavity. In an embodiment of the present invention, the outlet port of the industrial cavity is connected to an inlet end of the positive displacement outflow pump via an outflow tube. In another embodiment of the present invention, an outflow pressure transducer is further connected between the outlet port of the industrial cavity and the inlet end of the positive displacement outflow pump or between a proximal end of the outflow tube and the inlet port of the positive displacement outflow pump or directly to the industrial cavity.

In yet another embodiment of , the present invention, the positive displacement outflow pump is selected from the group comprising peristaltic pump, piston pump, gear pump, diaphragm pump and plunger pump. In still another embodiment of the present invention, the positive displacement outflow pump is a fixed flow rate pump, whose flow rate could be varied from one fixed flow rate value to another fixed flow rate value, or a variable flow rate pump and the same is a peristaltic pump. In one more embodiment of the present invention, the outlet end of the positive displacement outflow pump is connectable to a fluid collecting container. In one another embodiment of the present invention, the outlet end of the positive displacement outflow pump is connectable to the fluid collecting container through a fluid disposal tube.

In a further embodiment of the present invention, further comprising a controller means electrically coupled to at least one of the inflow pressure transducer, the outflow pressure transducer, the transducer attached to the cavity, the inflow pump or the outflow pump. In a further more embodiment of the present invention, the system further comprises a housing tube having a variable size constriction site being provided between the outflow port of the industrial cavity and an outflow region, the outflow region comprising of the fluid disposal tube, the fluid collecting container and the atmosphere. In an embodiment of the present invention, the distal end of the housing tube is connected to the fluid disposal tube or the fluid collecting container or the distal end of the housing tube opens directly into the atmosphere.

In another embodiment of the present invention, the inflow and the outflow positive displacement pumps are coupled to a common shaft for synchronously operating the two pumps.

In yet another embodiment of the present invention, the housing tube is provided with an electromechanical device, a solenoid, to enable the controller to vary the diameter of the constriction site. In still another embodiment of the present invention, if the inflow and the outflow pumps are coupled to the common shaft, the housing tube is provided with the controller controlled solenoid for varying the diameter of the constriction site.

In one more embodiment of the present invention, an inflow pressure pulsation dampening means is connected to the inflow port of the industrial cavity or to the inflow tube for dampening the pressure pulsations inside the cavity created by the positive displacement inflow pump.

In one another embodiment of the present invention, the inflow pressure variation dampening means comprises a pressure dampening fixed volume expansion chamber. In a further embodiment of the present invention, the inflow pressure variation dampening means comprises a single outlet syringe mechanism, the piston of the same being coupled synchronously to the positive displacement inflow pump through a coupling means and a single outlet end of the said syringe mechanism being connected to the inflow tube. In a further more embodiment of the present invention, an outflow pressure pulsation dampening means is connected to the outflow port of the industrial cavity or to the outflow tube for dampening the pressure pulsations inside the cavity created by the positive displacement outflow pump.

In an embodiment of the present invention, the outflow pressure variation dampening means comprises a single outlet syringe mechanism, the piston of the same being coupled synchronously to the positive displacement outflow pump through a coupling means and a single outlet end of the said syringe mechanism being connected to the outflow tube. In another embodiment of the present invention if the inflow and the outflow pumps are operated synchronously by coupling them to the common shaft, the inflow and /or the outflow pressure variation dampening means are optionally operated synchronously by coupling them to the same common shaft. In yet another embodiment of the present invention, the inflow and the out flow pumps operate simultaneously at fixed flow rates for indefinite time for the purpose of creating and maintaining any desired constant cavity pressure.

In still another embodiment of the present invention, a bypass tube is provided between the inlet and the outlet ends of the cavity. In one more embodiment of the present invention, the bypass tube has a controllable constriction site.

In one another embodiment of the present invention, the bypass tube has a pressure release valve which opens in case the pressure exceeds a predetermined value.

In a further embodiment of the present invention, the bypass tube has a unidirectional valve which allows fluid to pass in one particular direction.

In a further more embodiment of the present invention, the said industrial cavity is a pipe meant for fluid transportation, a feed chamber of a membrane filtration system or a cavity housing a chemical a chemical reaction.

The present invention also provides a method of determining the instantaneous real time rate at which fluid escapes via a semi permeable membrane installed in the feed chamber of a reverse osmosis system without using any type of fluid flow rate sensor, said method comprising the steps of:

(a) pushing fluid from a fluid source reservoir to an inflow port of a cavity at a controlled flow rate through a fluid supply conduit tube, a positive displacement inflow pump and an inflow tube, the flow rate of the inflow pump being termed as the inflow rate"Rl";

(b) injecting the fluid at the controlled flow rate into the cavity for pressurizing the cavity;

(c) removing a fluid from the cavity via the outlet port of the cavity; (d) actively extracting the fluid via the outlet port of the cavity and transporting it to a fluid collecting reservoir at a controlled flow rate, through a outflow conduit tube, a positive displacement outflow pump and a waste fluid carrying fluid disposal tube wherein the flow rate of the said outflow pump being termed as the outflow rate "R2", (e) measuring instantaneously the pressure inside the cavity using a pressure transducer and denoting the determined pressure as "P", and

(f) obtaining the instantaneous real time rate of permeate formation as:

K_pf * P = (R1-(R2+R3))² wherein K_Pf is a constant and R3 is the instantaneous real time rate of permeate formation.

Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of various components related to the continuous fluid flow irrigation system for transporting fluid across an industrial cavity under substantially constant pressure and reduced turbulence. Accordingly, the components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein. The terms "comprises", "comprising", or any other variations thereof are intended to cover a non-exclusive inclusion, such that a system that comprises list of components does not include only those components but may include other components that are not expressly listed or inherent to such system. An element proceeded by "comprises ...a" does not without more constraints, preclude the existence of additional identical components in the system.

The description in the following paragraphs is presented to enable any person skilled in the art to make and use the invention. For purpose of explanation, specific nomenclature is set forth to provide a through understanding of the present invention. Descriptions of specific applications, methods and apparatus are provided only as examples. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown hereunder, but is to be accorded the widest scope consistent with the principles and features disclosed herein. Description of the Embodiments:

The present invention is related to fluid mechanics and can be used to pressurize diverse type of industrial cavities ranging from a long pipe to a cavity harboring a chemical reaction. The invention has many industrial applications and a few examples of the same are as follows: 1. A novel and efficient system of fluid transportation through pipes 2. A system to efficiently pressurize the feed chamber cavity in membrane systems like reverse osmosis such that the real time rate of permeate formation is also known without using any flow rate or density measuring sensors

3. A system to monitor and modulate in real time the extent of completion of a chemical reaction as a function of the real time density variations at the reaction site

4. A system to actively dampen pressure pulsations of positive displacement pumps without using any feed back mechanism

A brief discussion of the above mentioned applications is as follows: System for fluid transportation through pipes: One of the simplest uses of the system of the present invention could be for transporting fluids through pipes. As indicated above, valuable fluids such as water, petroleum and gas are constantly transported over long distances through long pipes. The system proposed in the invention would help in transporting fluids in a more efficient manner. The system for transporting the fluids through pipes in accordance with the teachings of the present invention could comprise of the pipes acting as the industrial cavity.

In an embodiment of the present invention, the present invention provides a continuous fluid flow irrigation system for transporting fluid through a pipe under substantially constant pressure and reduced turbulence, said system comprising: a fluid source reservoir containing a fluid meant for being transported across the pipe; a fluid supply conduit tube connecting the fluid source reservoir to an inlet end of a positive displacement inflow pump and an outlet end of the said inflow pump being connectable to an inflow port of the pipe for pumping the fluid at a controlled flow rate through the pipe, the flow rate of the inflow pump being termed as the inflow rate; an outflow port of the pipe being connectable to an inlet end of a positive displacement outflow pump for removing the fluid from the pipe at a controlled flow rate, the flow rate of the outflow pump being termed as the outflow rate, and a housing tube having a controllable constriction site is being provided between an inflow region and the inflow port of the pipe, the inflow region comprising of the fluid source reservoir, the fluid supply conduit tube and the atmosphere; such that the housing tube by- passes the inflow pump and provides a route for any excess fluid present in the pipe to bypass the inflow pump and go back to the inflow region when the inflow and the outflow pumps are operated at substantially fixed flow rates thereby maintaining the pressure inside the pipe at a stable value and minimizing turbulence inside the pipe. The system proposed in the present invention comprising of two positive displacement pumps attached to two ends of the pipe along with the housing tube can work simultaneously for indefinite time in order to transport fluid through the pipe such that pressure at any point inside the pipe remains unchanged for indefinite time. The system proposed in the present invention substantially dampens the pressure pulsations including the pressure pulsations created by positive displacement pumps in an active manner without utilizing any type of a feed back mechanism.

A system to efficiently pressurize the feed chamber cavity in membrane systems like reverse osmosis such that the real time rate of permeate formation is also known without using any flow rate or density measuring sensors:

The present invention is related to enhancing the efficiency and accuracy of 'membrane filtration processes' such as Reverse Osmosis, Ultrafiltration, nanofiltration, microfiltration and dialysis. Those conversant in the art would understand the principles and terminologies associated with membrane systems like Reverse Osmosis. In most prior art reverse osmosis systems the feed fluid is introduced into the feed chamber cavity by utilizing a dynamic pump, a positive displacement pump or gravity and the pressure inside the feed chamber cavity is maintained by either incorporating a constriction site over the outlet tube of the feed chamber which carries the feed concentrate or by varying the inflow rate, that is the feed flow rate. In the system of the proposed invention the pressure inside the feed chamber cavity can be maintained absolutely independent of the feed flow rate without incorporating a constriction site over the outlet side of the feed chamber cavity. Thus the feed cavity pressure and the feed cavity flow rate can be maintained absolutely independent of each other such that any can be varied without affecting the value of the other, and without incorporating any constriction site over the outflow side. Such feature of the proposed invention can greatly enhance the efficiency and accuracy of reverse osmosis systems.

The volume of permeate formed per unit area of the semipermeable membrane in unit time is being termed as the 'permeate flux rate¹. No membrane system is 100% perfect thereby implying that some contaminants invariably pass through the membrane along with the permeate. However the relative concentrations of the said contaminants in the permeate is also a function of the 'permeate flux rate'. Thus by suitably adjusting and maintaining the permeate flux rate at a desired value the total and relative concentrations of contaminants inside the solute can be maintained at a desired minimum or maximum values. The instantaneous real time permeate flux rate is constantly known in the system of the proposed invention and this feature can help in adjusting the total and relative concentrations of permeate contaminants by great accuracy. Such feature can be of immense use in certain high end industrial and pharmaceutical processes.

The permeate flux rate is a function of the feed line pressure such that the permeate flux rate increases as the feed pressure increases. However increased feed pressure also results in increased salt rejection but the relationship is less direct than for water flux. Because RO membranes are imperfect barriers to dissolved salts in feed water, there is always some salt passage through the membrane. As feed water pressure is increased, this salt passage is increasingly overcome as water is pushed through the membrane at a faster rate than salt can be transported. However, there is an upper limit to the amount of salt that can be excluded via increasing feed water pressure. As the plateau in the salt rejection curve indicates, above a certain pressure level, salt rejection no longer increases and some salt flow remains coupled with water flowing through the membrane. For each specific membrane system there is an optimum pressure which is related to the most optimum salt rejection. Thus if the feed water pressure could be maintained at a desired optimum value, independent of other factors, the efficiency of the membrane system could be enhanced and a permeate of a relatively more predictable concentration composition could be obtained, and the same has been made possible by the system of the proposed invention. The permeate flux rate is also a function of the feed concentration such that if feed pressure remains constant, higher salt concentration results in lower permeate flux rate. Thus in an abnormal eventuality if the feed concentration becomes variable in nature the permeate flux rate would also not remain constant. In the proposed invention the instantaneous real time permeate flux rate being always known such feature could be usefully deployed in maintaining a constant permeate flux rate in case the feed concentration varied. The same being achieved by suitably varying other parameters like pressure, the feed flow rate as provided by the system of the proposed invention.

The permeate flux rate is primarily affected by the phenomena of concentration polarization (i.e. solute build-up) at the membrane surface. Thus the permeate flux rate is a function of the concentration polarization such that the permeate flux rate decrease as the concentration polarization increases. Any turbulence inside the feed chamber could retard the build up of the concentration polarization which in turn would not allow the permeate flux rate to fall. In the system of the proposed invention the turbulence levels inside the feed chamber can be maintained in a predictably controlled manner and such feature of the invented system can help in preventing a fall in the permeate flux rate by avoiding a build up of excess concentration polarization.

The permeate flux rate is also a function of the feed flow rate such that with feed pressure remaining constant the permeate flux rate increases if the feed flow rate increases. In the proposed invention the feed flow rate can be varied in a desired predictable manner without varying the feed pressure and such feature of the invented system can help in maintaining a constant permeate flux rate by varying the feed flow rate absolutely independent of the feed pressure. A system to monitor and modulate in real time the extent of completion of a chemical reaction as a function of the real time density variations at the reaction site

Chemical reactions occurring under static conditions or under dynamic conditions are an essential part of innumerable industrial processes. The proposed invention helps in gauging in real time the extent of completion of chemical reactions as a function of the real time density variations at the reaction site. There are innumerable chemical reactions which need to be carried out in closed cavities under continuous flow irrigation conditions or under static conditions. Continuous flow irrigation here means that fluid constantly enters the cavity via an inlet cavity opening and also simultaneously escapes via an outlet cavity opening, as a result of which a positive pressure is created inside the cavity. The present invention is basically a fluid management system which is meant to pressurize a chemical reaction cavity through which liquid or gaseous chemical constituents or their mixture is allowed to pass at any desired flow rate and at any desired pressure such that both pressure and flow rate could be maintained absolutely independent of each other but without incorporating any constriction site on the outflow side of the cavity. The said industrial cavity harboring chemical reactions could also be lined by a catalyst. Chemical reactions are influenced by factors such as pressure, temperature, flow rate at the reaction site, turbulence, catalyst and density variations. For example the rate of a specific chemical reaction may be accelerated by increasing the pressure or temperature while the same may retard the pace of another reaction. Similarly the reaction rate may be enhanced by using a catalyst. With other parameters remaining constant a decrease in the rate of a chemical reaction may also indirectly signify a deterioration or consumption of a catalyst. Thus chemical reactions are complex phenomenon which is influenced by multiple factors in variable relative proportions.

Many chemical reactions are also reversible in nature and their direction and extent of completion are influenced by many factors like pressure, temperature, flow rate at the reaction site, turbulence and catalyst. It is difficult to determine in real time the extent and progress completion in such reactions. Let us consider a hypothetical reaction A+B-C+D. The molecules A and B shall henceforth be termed as 'reactant' while molecules C and D shall henceforth be termed as 'product'. According to the law of conservation of mass, the total mass of the reactant and product always remains constant while the density of the product could be different from the density of the reactant. With other parameters remaining constant the determination of the overall density of the reactant product mixture at any stage of the reaction could be beneficially utilized to gauge the progress of the reaction in either direction, the progress of the reaction being taken as a function of the said density variations. If both reactants and products are liquids then the said density changes can be gauged by utilizing the resultant volume changes under open conditions, however if any of the product or reactant is a gas then the same might not be possible because the gas would escape under open conditions. Consider a hypothetical reaction A+B-C+D where the reactant or the product is a gas and let it be assumed that, besides other factors, this reaction needs to be carried out at a desired constant pressure and temperature. The only practical way is to conduct such a reaction inside a closed cavity whose volume capacity could be varied in accordance with the density changes such that the pressure always remained constant. According to the formula PV/T = Constant (where P = pressure, V = volume) the temperature in such a reaction would remain constant since pressure P is maintained constant. However such a method is quite unpractical but the density changes could definitely be gauged by utilizing the required variation in the cavity volume needed to maintain constant pressure. Thus the over all density of the reactants and products inside the said variable volume cavity could be indicative of the overall extent of progress of the reaction. If such a reaction were to be carried out under continuous flow irrigation conditions, such that the reactant mixture constantly enters the cavity while the product mixture constantly escapes the cavity via an independent cavity outlet, then it is not possible to gauge the associated density changes in real time in the stated manner. However the system of the proposed invention provides a method for gauging in real time the density variations without utilizing any kind of sensor to measure the fluid flow rates, the fluid density or the fluid volume.

Let us consider another hypothetical reaction A+B^C+D which need to be carried out under the said continuous flow irrigation conditions. Let it be further assumed that such reaction needs to be carried out at a desired cavity pressure P and at a cavity outflow rate R2. Here R2 is the rate at which the liquid chemical constituents continuously escape from the outlet end of the cavity. The system of the proposed invention provides that irrespective of other factors such reaction can be carried at any desired P and for any desired R2 such that both P and R2 are maintained absolutely independent of each other, such that both could be varied absolutely independent of the other and as already mentioned no constriction site is incorporated over the outflow side of the cavity. As already stated the system of the proposed invention also helps in constantly gauging the instantaneous real time relative density variations which would provide a real time evaluation of the percentage completion of the chemical reaction under dynamic conditions imposed by 'continuous flow irrigation¹. Such a feature could be beneficially utilized in high end pharmaceutical processes, gas cracking where in larger molecules are broken into smaller ones under controlled conditions and in many other industrial applications. Further the system of maintaining P and R2 absolutely independent of each other, without using a restrictive valve on the out flow side, can enhance the efficiency and accuracy of many other chemical reactions of industrial significance. Let us consider another hypothetical reaction A+B^C+D which need to be carried out, inside a cavity lined by a catalyst, under the said continuous flow irrigation conditions. In such a chemical reaction, with other factors remaining constant, the time duration for which the liquid or gaseous chemical constituents remain in contact with the catalyst influences the rate of the chemical reaction. In the system of the proposed invention the knowledge of the real time relative density variations could be beneficially utilized to maintain an optimum R2 at which the cavity constituents remain in contact with the catalyst for an optimum time such that a desired rate of chemical reaction is maintained even under dynamic conditions of 'continuous flow irrigation'. Such a feature of the invention could be beneficially used in pharmaceutical industry, especially for producing complex bio molecules. Let us consider another hypothetical reaction A+B^C+D which need to be carried out under the said dynamic continuous flow irrigation conditions. With other factors remaining constant any reduction in the rate of a chemical reaction, determined after evaluating the real time relative density variations, could indicate a deterioration or consumption of the catalyst in real time. By the help of the invented system the real time rate of consumption or deterioration of catalyst can be gauged by evaluating the real time density variations. USE OF THE INVENTION IN REVERSE OSMOSIS

In physical terms the invention consists of two positive displacement pumps installed on an inlet and an outlet end of an industrial cavity such that the two pumps can run simultaneously at fixed flow rates for indefinite time in order to create and maintain any desired cavity pressure absolutely independent of the cavity flow rate and without incorporating any constriction site on the cavity out flow side, such that the real time rate of diffusion or escape of fluid via the cavity walls is also known.

In simple terms the invention is finds application in a situation wherein fluid flows through a cavity in the 'continuous flow irrigation¹ mode. Here 'continuous flow irrigation' means that fluid enters a cavity via an inflow tube which is attached at an inlet side of the cavity and fluid is simultaneously removed from the cavity via an outflow tube which is attached at the outlet side of the cavity. Another useful embodiment of the invention is an active pressure dampening system without a feedback mechanism which would substantially dampen the pressure pulsations created by any or both positive displacement pumps. Such a 'pressure dampening system' could minimize or even accentuate the amplitude of cavity pressure pulsations produced by the positive displacement pumps.

In context with proposed use of the invention in membrane systems, the present invention is a system for pressurizing the feed chamber cavity in membrane filtration systems such as reverse osmosis deploying cross flow filtration. The meanings of the terms 'feed chamber' and 'cross flow filtration' would be known to those skilled in the art. However in order to understand the invention in an easier manner the cavity shall be assumed to be made up of an impervious material like steel. Henceforth for an easier understanding, unless specifically mentioned, the term 'cavity' shall be deemed to represent a cavity made up of an impervious material like steel. Henceforth again for an easier understanding, the term 'fluid' shall be deemed to refer to a substance like water unless so specified. The inflow and outflow pumps could be any type of positive displacement pumps like peristaltic pump, piston pump or diaphragm pump. However, again for an easier understanding of the invention, unless and until so stated, henceforth the term pump shall be deemed to refer to 'peristaltic pump'. Also henceforth the term 'industrial process' shall be deemed to refer to a 'membrane filtration process' like Reverse Osmosis.

The block diagram of the invention in context with 'Reverse Osmosis' is contained in figure 10 and the same shall be discussed in a later section of this manuscript. Figure 1 shows a layout of the invention in which the inflow and the outflow 'pressure pulse dampening systems', have been shown. However in order understand the invention in a simpler manner, first the basic invention without the 'pressure pulse dampening systems' shall be discussed. The basic schematic diagram of the invention is shown in figure 2. Figure 2 is similar to figure 1 except that in figure 2 the two 'pressure pulse dampening systems' have not been included. The two peristaltic pumps 5 and 14 operate simultaneously in order to distend a cavity 18 in such a manner that the cavity pressure is totally independent of the cavity outflow rate. Figure 2 represents the basic schematic diagram of the invention. Please note that the controller being used in the system shown in figure 2 is an optional feature and the system would provide most of the features even without the controller. The figure 3 represents the schematic diagram of the invention but without a controller system. Thus figure 3 is a basic mechanical version of the invention. A human operator is required to operate such mechanical version of the invention shown in figure 3. The controller being used in the present invention merely assists the user in arriving easily at some of the additional functions which otherwise can also be performed manually. Thus, in this manuscript the mechanical version of the invention shown in figure 3 is being discussed in more detail only to explain the basic physical principals of the invention with a greater clarity.

Referring to figure 3, the system shown in this figure comprises of two peristaltic pumps which can maintain a predictably precise stable cavity pressure for indefinite time by working simultaneously at constant rotational speeds. Pump 5 pushes fluid into the cavity 18, while pump 14 simultaneously extracts fluid out of the cavity 18. The inlet end of the inflow peristaltic pump 5 is connected to a fluid source reservoir 1 via tube 2. The open end of tube 2 is constantly submerged in a fluid contained inside the reservoir 1 at atmospheric pressure. One end of the tube 7 connects the 'T junction' 3 situated at the inlet end of the pump 5 while the other end of tube 7 connects with the 'square junction' 6 situated at the outlet end of the pump 5. The 'T' junction 3 is thus the meeting point of three tubes, namely 2, 4 and 7. Similarly the square junction 6 is the meeting point of four tubes, 4, 9, 7 and 10. The rollers of the peristaltic pump 5 continuously compress and roll over the entire length of tube 4 thus displacing fluid in the direction of the curved arrow. This curved arrow denotes the direction in which the rollers of the peristaltic pump 5 rotate. Tube 7 has a constriction point 8 which can be located anywhere along its length. Such constriction point refers to a point where the inner diameter of the lumen of tube 7 is reduced in comparison to the lumen of the rest of the tube 7. Such constriction may be a permanent constriction in the lumen of tube 7 or it may be a variable constriction whose diameter may be increased or decreased as desired. A pressure transducer 17 is attached at one end of tube 9 while the other end of tube 9 is connected anywhere on inflow tube 10. For practical convenience it is desirable that the said other end of tube 9 be connected in the up stream part of the inflow tube 10 such as at the square junction 6. The pressure transducer 17 measures the fluid pressure via a column of liquid or air present in the lumen of tube 9. The fluid pressure as measured by the pressure transducer shall be referred to as P. In this manuscript the term 'P' shall frequently be used to refer to the actual pressure inside the cavity but in physical terms P is the pressure sensed by the transducer 17 at point 6. The pressure transducer 17 may also be in the form of a membrane diaphragm incorporated in the wall of the inflow tube 10 such that this membrane diaphragm is in direct contact with the fluid contained in the inflow tube 10, such that the linear movement excursions of the said membrane are interpreted as pressure of the fluid inside the inflow tube 10 by a suitable pressure transducer. Such type of pressure sensor being directly incorporated in the wall of the inflow tube 10 senses the fluid pressure without the intervention of tube 9. The basic purpose of the transducer is to measure the fluid pressure inside the inflow tube 10, such as at point 6, thus the mechanical construction of the transducer is not important as long as it measures the fluid pressure. For the sake of simplicity the existence of tube 9 shall be continued to be considered in the rest of the manuscript. Practically it could be more beneficial to attach a pressure transducer directly to the cavity 18. Such a provision has been shown in figure 6 wherein a pressure transducer 73 has been fluidly coupled to cavity via tube 72. Coming back to figure 3 the peristaltic pump 14 attached to the outflow side of the cavity actively extracts fluid out of the cavity 18 via the out flow tube 12. The outlet end of the pump 14 is connected to a fluid disposal tube 15 which opens into a fluid collecting reservoir 16. The rollers of the pump 14 constantly compress and roll over the entire length of the peristaltic pump tubing 13 thus displacing fluid in the direction of the curved arrow which also corresponds with the direction of pump rotation.

The reservoir 1 could also be a closed container containing a pressurized fluid, however in such case the proximal end of tube 7 may need to open into the atmosphere or into another separate container as discussed in the subsequent paragraphs. However while describing the basic functioning of the invention, the container 1 shall continued to be assumed to be an open container at atmospheric pressure.

In order to understand the invention in a simpler manner both pumps are being considered to be identical in all respects and all the tubes are also being considered to be having the same uniform inner diameter. However the inner diameter of the tubes can also be different. Tubes 4 and 13 consist of a soft resilient plastic material which can be efficiently compressed by the rollers of the peristaltic pumps. The other tubes also consist of a suitable resilient plastic material. It is assumed that all the components shown in figure 3, including the two pumps, all tubes and the said cavity, are placed at the same horizontal height with respect to the ground. Also the rollers of pumps 5 and 14 should press adequately over tubes 4 and 13 in such a manner that there is no leak through these tubes when the pumps are stationary. It is also assumed that there is no abnormal leak of fluid in the irrigation system, for example leak via an accidental hole made in any irrigation tube.

The proximal end of the constriction site housing tube 7 instead of being connected with tube 2 at the ^ζT' junction 3 can also open directly into the fluid source reservoir 1. This shall not affect the efficiency of the system in any way but it may be practically difficult from the point of incorporating an extra tube. However such provision would be indispensable in case the pump 5 rotates at extremely low RPM in which case the fluid shall not be sucked into the tube 2 because an adequate suction pressure shall not be created at a point such as point 3. However if the proximal end of the tube 7 opens directly into fluid source reservoir 1 then fluid would be sucked into tube 2 even if the pump 5 rotates at infinitely low RPM. Such provision is separately shown in figure 6 and the said tube has been labeled as 11 but it has intentionally not been included in figures 1, 2 and 3 in order to keep the drawings simple. The proximal end of the tube 7 could also directly open into the atmosphere and such provision could be especially beneficial in case the fluid source 1 contained fluid at a pressure higher or lower than atmospheric pressure. The proximal end of tube 7 could also directly open inside a 'separate container' other than container 1. The just stated 'separate container' could also be an open container like container 1 placed upside down so that any gas escaping from the open proximal end of tube 7 could collect, at atmospheric pressure, beneath the upper close part of this container placed upside down, so that this collected gas is again collected could be passively sucked into the cavity whenever the cavity pressure P tends to decrease, thereby helping in maintaining the pressure inside the cavity 18. Again for the sake of simplicity such provision is not included in the drawings. Also a constriction site housing tube similar to tube 7 labeled as 17 can be attached to the outflow tube 12 as shown in figure 6. The distal end of tube 17 could also open directly into the atmosphere or into a 'separate container' other than container 16. The just stated 'separate container' could also be an open container like container 16 placed upside down so that any gas escaping from the distal open end of tube 17 could collect, at atmospheric pressure, beneath the upper close part of this container placed upside down, so that this collected gas is again collected could be passively sucked into the cavity whenever the cavity pressure P tends to decrease, thereby helping in maintaining the pressure inside the cavity 18. Again for the sake of simplicity such provision is not included in the drawings. In the said tube 17 the said constriction site is labeled as 19. Such tube can be used to attach an additional pressure dampening devise, it can be used for maintaining cavity pressure, for flushing or a pressure release safety valve may be incorporated at this site. Also an additional pressure transducer 63 may also be attached on the out flow tube 12, if desired, as shown in figure 6. However the said pressure transducer 63 has intentionally not been included in the main block diagrams of the invention because by doing so it would have become very difficult to explain the basic physical principals of the invention. Also a pressure transducer 73 can be additionally attached to cavity 18 via tube 72. Also bypass tube may be provided between the two ends of the cavity 18 as an optional feature. Such bypass tube, though not included in the drawings, could contain a constriction site like 8, or a dynamic constriction (refer to subsequent paragraphs), or a pressure release value or a unidirectional flow regulating valve. Such embodiments related to the optional bypass tube between the cavity ends could help in maintaining cavity pressure, reduce turbulence and protect against excessive accidental pressure.

In order to clearly understand the system shown in figure 3 it would be helpful to discuss the functioning of the inflow peristaltic pump 5 as a separate entity as shown in figure 4. The rollers of pump 5 move in the direction of the curved arrow and squeeze over the entire length of peristaltic pump tubing 4. Initially tubes 2, 4, 7 and 9 contain fluid at atmospheric pressure and the free open end of tube 2 is submerged in the fluid contained inside the fluid source reservoir 1. The moment the constriction site 8 is fully occluded a column of fluid is immediately sucked into tube 4 via tube 2, and thus fluid starts accumulating in the proximal parts of tubes 9 and 7. As the fluid fills in tube 9 it pushes a column of air distal to the fluid column created in tube 9 and the pressure of this compressed air column is sensed by the pressure transducer 17. The fluid pressure and the pressure of the said compressed air column are same thus the pressure transducer 17 actually senses the fluid pressure. If tube 7 continues to remain fully occluded at the constriction site 8, the fluid continues to accumulate inside tubes 9 and in that part of tube 7 which lies between point 6 and the constriction site 8, and the pressure transducer 17 thus displays a continuously rising fluid pressure. The moment the block at the constriction site 8 is partially released the fluid escapes in the form of a jet through the partially open constriction opening 8 in the direction of point 3. With the constriction opening 8 being only partially blocked, if the pump 5 continues to rotate at a constant rotational speed the fluid pressure ultimately gets stabilized at a fixed value provided the internal diameter of the constriction site 8 is not further varied. The diameter D of the constriction site 8 ranges from a minimum non-zero value to a maximum value which is less than the overall diameter of the rest of the housing tube, that is range between when the constriction site 8 is fully occluded, to a maximum value which is less than the diameter of tube 7. Henceforth in this manuscript the inner diameter of the constriction site 8 shall be deemed to be fixed at some predetermined value D, unless otherwise stated. Referring to figure 5, this figure is similar to figure 3 but a limited region of the irrigation circuit having an almost same uniform pressure has been shaded black. Due to frictional resistance experienced by the moving fluid the pressure at point 6, as sensed by the transducer 17, is always found to be higher than the actual pressure inside the cavity 18 but for relatively low cavity flow rates or if the total length of the inflow tube, the outflow tube and the cavity is relatively small, say 4 meters long, the said pressure difference is so small that it may be neglected from a practical point of view. The term 'out flow rate' is being referred to the flow rate of pump 14. Also, the said pressure difference remains constant at any fixed outflow rate. Though the said pressure difference is negligible but if desired its effect can also be totally negated by subtracting its value from the pressure reading of the transducer. In this manner it is possible to determine the actual cavity pressure by using the pressure transducer 17 located far away from the cavity.

Referring to figure 3 it shall be first described as to how the system of the proposed invention can be used mechanically, that is without a controller. The peristaltic pumps 5 and 14 can be made to work at any fixed rotational speed and the fluid flow rate of each pump is directly proportional to the pump RPM or the pump rotational speed. Thus any precise pump flow rate can be generated by selecting a suitable pump rotational speed. The fluid flow rate of pump 14 shall henceforth be denoted by R2 and shall be termed as the Outflow rate'. The fluid flow rate of pump 5 shall be denoted by Rl and shall be termed as the 'inflow rate'. Here it is to be noted that the term 'inflow rate' Rl is not the true inflow rate for the cavity 18, as might be suggested by the literary meaning of the term 'inflow' because Rl is not the actual rate at which fluid enters into the cavity 18 because some fluid also constantly escapes through the constriction site opening 8. Henceforth in this entire manuscript the term 'inflow rate' shall only refer to the flow rate of the inflow pump 5 unless specifically mentioned. However the term Outflow rate' R2 does correspond to the literary meaning of the term 'outflow' because R2 is equal to the rate at which fluid flows out of the cavity 18. Initially an outflow rate R2 is selected by selecting a suitable rotational speed for pump 14. Next the maximum flow rate at which fluid could be allowed to enter into the cavity via the inflow tube 10 is selected and the inflow pump 5 is set to work at such flow rate. After fixing desired values for R2 and Rl the system is started and the diameter of the constriction site 8 is gradually reduced. As the diameter of the constriction site 8 is reduced fluid starts flowing into the cavity and the pressure inside the cavity starts rising. When the desired pressure is achieved inside the cavity the diameter of the constriction site 8 is not reduced any further and is fixed. The diameter of the constrictions site at this stage is termed as "D". The constriction site may also be a plastic or metal piece which has a hole in the centre such that the diameter of the hole is permanently fixed at some value D. If a constriction 8 has a permanently fixed diameter then only the flow rates of pumps 14 and 5 have to be set before the system can be made operational. It is important to note that for a fixed value D, any specific combination of Rl and R2 will be associated with only a specific cavity pressure P. This implies that the pressure sensor 17 is actually an optional feature since any desired pressure value P can be created by incorporating a suitable combination of Rl and R2. Thus the invention works even without the sensor 17. Cavity pressure and the outflow rate, both can be altered independently without varying the value of the other

Referring again to figure 3 let us consider an hypothetical industrial process in which fluid is flowing through the cavity 18 at an outflow rate R2 and inflow rate Rl with the constriction 8 diameter being been fixed at some value D and a resultant cavity pressure P being created maintained. In such hypothetical situation as long as R2 and Rl are not altered the cavity pressure P remains predictably constant. In the said hypothetical industrial process if the cavity pressure needs to be increased without altering the out flow rate R2 then all that is needed is to start increasing the value of Rl and stop doing so when the desired higher cavity pressure is achieved. Similarly if the cavity pressure needs to be decreased without altering the out flow rate R2 then Rl is decreased till the desired lower cavity pressure is attained. Similarly if in the said hypothetical industrial process if the outflow rate R2 needs to be increased without altering the cavity pressure P then the value of R2 is increased by the desired magnitude but simultaneously the value of Rl is also increased by a similar magnitude. Similarly, if the outflow rate R2 needs to be decreased without altering the cavity pressure P then the value of R2 is decreased by the desired magnitude but simultaneously the value of Rl is also decreased by a similar magnitude. Thus if Rl and R2 are simultaneously increased or decreased by the same magnitude the cavity pressure does not vary provided the value D remains constant. The preceding statements shall now be explained by the help of a numerical hypothetical example. In reference to figure 3 considering a hypothetical situation in which the outflow rate R2 being 100 ml/minute, the inflow rate being Rl and the resultant cavity pressure being 80 mm Hg. If the outflow rate R2 needs to be increased to 322 ml/minute by maintaining the cavity pressure at the same value of 80 mm Hg then the outflow rate is increased to 322 ml/minute and the inflow rate is increased by 222 ml/minute, because 322 ml/min - 100 ml/min = 222 ml/minute. As already mentioned in this paragraph if both inflow and outflow rates are increased or decreased by the same magnitude the cavity pressure does not vary. Thus the final inflow rate becomes Rl + 222 ml/minute, where Rl was the initial inflow rate. Thus in the proposed invention the cavity pressure and the outflow rate both can be altered absolutely independent of each other without affecting the value of the other parameter. Such a feature could be beneficially used to increase or decrease the rate at which the feed fluid passes through the feed chamber in a reverse osmosis system, without affecting the pressure in the feed fluid. Mechanical version of the invention

The mechanical version of the invention shown in figure 3 can be used practically in industrial processes but the same could be practically difficult. Also the mechanical version has certain practical limitations which shall be explained in the later sections of the manuscript. This mechanical version of the invention has been discussed only in order to explain more clearly the physical principals associated with the controller based version of the basic invention shown in figure 2. Controller based version of the invention Referring to figure 2, figure 2 and figure 3 are similar except that in figure 3 the controller system is not included. A tachometer, not shown in the diagrams, is coupled to each peristaltic pump and sends information regarding the pump rotation speed to the controller 19 via wires 60 and 58. The pump flow rates being directly proportional to the pump rotation speed the tachometer signal always conveys flow rate related information to the controller. As already mentioned .both peristaltic pumps have been considered to be similar in all respects because this makes it easier to understand and operate the system. However the two peristaltic pumps may also be different in context with the inner diameter of the peristaltic pump tubes 4 and 13 but in such case suitable modifications have to be made in the controller programming in order to operate the system as described in this manuscript. The controller also regulates the rotation speed of the two pumps via electrical signals sent through wires 59 and 61. The pressure transducer 17 conveys the pressure signal to the controller via wires 62. On the basis of a pressure feed back signal received from the pressure transducer 17 the controller regulates the rotational speed of the inflow pump 5. The outflow pump 14 works at fixed outflow rates and the flow rate of this pump can also be changed by the help of the controller via suitable electrical signals sent via wires 61. A provision exists by which desired values for P and R2 can be fed into the controller and the values Rl, R2 and P can be continuously displayed via suitable display means incorporated in the controller. The controller can be programmed to perform many special functions. Method of operating the controller based version of the invention

Referring to figure 2, at the beginning of the industrial process desired values for the cavity pressure P and outflow rate R2 are selected. The said desired values of P and R2 are fed into the controller via suitable input means incorporated in the controller. The diameter D at the constriction site 8 remains fixed at some pre selected value. The diameter of the constriction site 8 is so chosen that it suits the operational needs of the industrial process. When the system shown in figure 2 is operated the controller 19 instructs the outflow pump 14 via wires 61 to continuously extract fluid out of the cavity 18 at a desired fixed outflow rate R2. Thus all through the industrial process the outflow rate remains fixed at R2 irrespective of any internal or external factors unless intentionally changed. The cavity pressure is sensed by the pressure transducer 17 and a corresponding pressure feedback signal is sent to the controller via wires 62 on the basis of which the controller regulates the inflow rate Rl, via wires 59. After the system is made operational the controller 19 gradually increases the inflow rate up to the point where the desired preset cavity pressure P is achieved. Let the value of the inflow rate at which the desired cavity pressure is achieved be termed as 'Rl. Final'. It is obvious that the value 'Rl. final' is actually determined by the controller by a pressure feed back mechanism and such determination of the value 'Rl .Final' is based on the preset values of R2 and P. The controller could be so programmed that once the value 'Rl .Final' is achieved and is maintained for a desired minimum time interval, for example 60 seconds, after which the controller releases the inflow pump 5 from its pressure feedback control mechanism and allow the inflow pump 5 to operate on its own at the inflow rate 'Rl .Final' which was determined by the controller. In this manner the two peristaltic pumps continue to work at fixed flow rates to maintain a desired stable cavity pressure. The controller is also programmed that in case the cavity pressure subsequently alters, for example due to a variation in permeate flux rate, by a desired minimum magnitude and for a desired minimum time, which may hypothetically be 60 seconds, the inflow pump 5 again comes under the pressure feedback control of the controller and a new value of 'Rl. Final' is determined by the controller after which the inflow pump 5 is again allowed to be operated without the pressure feedback mechanism at the newly determined 'Rl. Final' inflow rate. Such sequence of events continues to occur throughout the industrial process. Taking an imaginary example if the total industrial process time is 60 minutes then it may be hypothetically possible to operate the inflow pump independent of the pressure feedback mechanism for 55 minutes and under the control of the pressure feedback mechanism for 5 minutes. However, provision of operating the inflow pump 5 under a pressure feedback mechanism all through the industrial process could also be incorporated depending on the industrial requirement.

The advantage of operating the inflow pump independent of the pressure feedback mechanism The only reason for operating the inflow pump 5 independent of the pressure feedback mechanism is to avoid unnecessary corrections of insignificant pressure variations inside the cavity. In the present invention, the minor transient insignificant variations in cavity pressure occurring due to any reason are automatically corrected by the constriction site 8 in a passive manner without the need of a controller. If the pressure inside the cavity increases transiently a minute quantity of fluid which is pushed out of the cavity escapes via the constriction site 8 towards point 3. It is to be noted that the part of tube 7 between point 8 and 3 is at atmospheric pressure thus the fluid which is expelled from the cavity escapes through the constriction site 8 against a zero pressure head, which being atmospheric pressure. Thus, all transient, insignificant variations in cavity pressure get stabilized at the desired preset value within a fraction of seconds. Alternatively if the pressure inside the cavity decreases a suitable volume of fluid is sucked into the cavity from the irrigation circuit, such as from the region of point 6, and this is accompanied by a corresponding transient decrease in the flow rate at which fluid is escaping via the constriction site 8 in the direction of point 3 but if the magnitude of the pressure fall is relatively more then fluid may even be sucked into the cavity via the constriction site 8. This implies that the constriction site 8 is helping in maintaining a stable cavity pressure by suitably varying the magnitude of an imaginary fluid flow vector passing through the constriction site 8. Normally the direction of such imaginary vector is always towards point 6 while its magnitude constantly varies to take care of the pressure changes. However, if the minor insignificant transient pressure changes are made to be corrected by a controller then the cavity wall may exhibit significant irregular pressure fluctuations. However, if the pressure variation is relatively larger in magnitude and more permanent in nature a controller may be required to correct the same. As explained in the previous paragraph the controller can be so programmed that the inflow pump 5 automatically comes under the pressure feedback control mechanism of the controller in case the cavity pressure alters by a desired minimum preset magnitude and for a desired preset time interval, thus a new 'Rl .Final' inflow rate is established at which the inflow pump is again allowed to operate without the feedback control of the controller. Thus both pumps, 5 and 14, are essentially fixed flow rate pumps. However the flow rate of any of the said pump may be 'varied' to enable the pumps to run at any other fixed flow rate. It is important to understand that the just stated term 'varied' does not imply that any of the pump is a variable RPM pump because in such a situation the invented system cannot function. A dynamic constriction site

In context with the system shown in figure 2 it is also possible to have a system in which the cavity pressure is maintained and regulated by continuously varying, by the help of a controller, the diameter D at the constriction site 8. Also a provision could be made wherein the diameter D at the constriction site 8 could also be brought under the influence of the controller only if the cavity pressure changed in a relatively more permanent manner, say for at least one minute and by some desired minimum pressure magnitude. For example, with other factors remaining constant, any permanent change in the permeate flux rate could be associated with a permanent change in pressure P and the controller shall have to vary D in order to maintain a desired stable cavity pressure. This implies that the diameter D shall be free from the influence of the controller for most of the time and shall be brought under the influence of the controller only when needed and that also for only a small part of the total industrial process time. Such a concept has been described in great detail in the previous paragraphs in context with figure 2. In the variable constriction system proposed in this paragraph both pumps 5 and 14 would always operate at desired but fixed flow rates and the cavity pressure would be regulated only by varying the diameter D at the constriction site 8. At the start of the industrial process the inflow and outflow rates would be set by feeding suitable flow rate values into the controller after which the controller would not influence or regulate the said two pumps and the cavity pressure would be maintained only by varying the diameter D at the constriction site 8. In order to vary the diameter at the constriction site 8 a suitable electromechanical devise such as a solenoid operated devise could be installed over the housing tube 7. Such a devise is not a devise which would either totally close or totally open the lumen of the pipe. By the help of the said devise the lumen diameter would be varied in a controlled manner and not just by totally opening or totally closing the lumen. The said devise could comprise of a long coil containing a movable long cylindrical magnet and this magnet piece by pressing over the tube, would vary the inner diameter of the tube. When current passes through such coil the magnet piece would either be pulled in or pushed out depending upon the direction of the current and the polarity of the magnet and the force which the said long cylindrical magnet piece could apply over the plastic tube would depend upon the current density passing through the coil or in simpler terms the amount of electrical energy supplied to the coil. Thus the controller shall regulates the magnitude of electrical energy supplied to the coil such that the magnetic rod presses over the tube with an adequate force and the inner diameter of the pipe would depend upon such force. Thus the inner diameter of the tube becomes a function of the current density. The system efficiency of the embodiment described in this paragraph could be used beneficially in a system of 'pump synchronization¹ which is described in the next paragraph. The variable constriction site as described in this paragraph has not been included in any of the figures only to keep the drawings simple.

A system of pump synchronization on a common shaft

It is a universally known fact that all positive displacement pumps are associated with a pulsatile flow due to the inherent reciprocating nature of such pumps. All positive displacement pumps generate a fluid flow which is pulsatile in nature and the frequency of such pulsations depends upon the RPM of the pump while the amplitude of the pulsations depends upon the resistance offered to the fluid flow. A method shall now be described to minimize or accentuate the amplitude of such pulsations by synchronizing the two peristaltic pumps on a single common central shaft. Referring to figure 7 the two positive displacement inflow and outflow pumps 5 and 14, which are preferably peristaltic pumps, are attached, that is mounted, on a common central driving shaft 26 which is in turn rotated by a common single motor 35. As shown in figure 7, the two peristaltic pumps 5 and 14 are mechanically coupled to a common driving shaft 26 which is driven by the motor 35. The motor 35 can be any suitable motor for example a DC electric motor. Points 27 and 28 refer to the mechanical coupling sites between the common driving shaft 26 and the pumps 5 and 14. In figure 7 the rollers of the peristaltic pump 5 have been referred to as 20, 22 and 24 and the symbolic attachment of these rollers with the central axis point 27 is denoted by lines 29, 30 and 31 respectively. The rollers of the peristaltic pump 14 have been referred to as 21, 23 and 25 and the symbolic attachment of these rollers with the central axis point 28 is denoted by lines 32, 33 and 34 respectively. The inner diameter of tube 4 related to the inflow peristaltic pump 5 has to be greater than the inner diameter of tube 13 related to the outflow pump 14 and the same had also been diagrammatically depicted in figure 7. The motor 35 rotates the common driving shaft 26 in the direction of the curved arrow located at the extreme right side of the diagram in figure 10. The common driving shaft 26 being mechanically coupled to the two peristaltic pumps, rotates these pumps in the direction of the two curved arrows related to each pump. In figure 7 the rollers of the two peristaltic pumps are seen located at 12 'O clock, 4 O clock and 8 'O clock positions respectively for both pumps. Let us consider rollers 20 and 25 related to the inflow and the outflow pumps respectively. Let it be assumed that when the motor 35 rotates the diving shaft 26 then it takes a time T for the roller 20 of the inflow pump 5 to move from its initial 12 O clock position to 4 'O clock position. Let it also be assumed the outlet end of the inflow pump 5 to be situated at 4 'O clock position. As the two pumps are mechanically coupled to the common shaft 26 the corresponding roller 25, related to the outflow pump 14 also takes the same time T to move from its initial 8 'O clock position to the 12 'O clock position. Let it also be assumed the inlet end of the outflow pump 14 is located at the 8 'O clock position. While the roller 20 moves from the 12 'O clock position to the 4 ' O clock position a positive pulse having a magnitude Ml tends to be created inside the cavity. While the roller 25 moves from the 8 'O clock position to the 12 'O clock position a negative pressure pulse having a magnitude M2 tends to be created inside the cavity. As the two peristaltic pumps are synchronized the said positive and negative pressure pulses having magnitudes Ml and M2 tend to cancel or negate the effect of each other and the magnitude M3 of the resultant pressure pulse is equal to Ml - M2. The magnitude of the resultant pressure pulse can be made almost negligible by suitable mechanical adjustments of the spatial alignment of the rollers of the two peristaltic pumps. The roller 20 related to the inflow pump and the roller 25 related to the outflow pump have been termed as 'corresponding rollers' because while roller 20 of the inflow pump creates a positive pressure pulse inside the cavity by pushing fluid into the cavity the roller 25 creates a negative pressure pulse inside the cavity by actively extracting fluid out of the cavity. A similar example can also be proposed for corresponding rollers 24 and 23, and rollers 22 and 21. In the system shown in figure 10 the spatial alignment of rollers related to both the pumps can be adjusted experimentally in order to achieve the minimal possible magnitude M3 for the resultant pressure pulse once the same is achieved the relative orientation or alignment of the corresponding rollers is not changed. It is clear that the magnitude of the said 'net pressure pulse' depends upon M2, M3 and the relative instantaneous spatial position of the said corresponding rollers. If the inflow and the outflow pumps are not synchronized via the common shaft 26 or if the pumps run at different RPM's the Ml and M2 can never cancel or negate the effect of each other thus leading to fluid turbulence. Thus by synchronizing the two peristaltic pumps via the common driving shaft 26 the fluid flow through the cavity can be made almost pulse less and very close to laminar or a streamline flow. Similarly the magnitude M3 of the said 'net pressure pulse¹ can also be accentuated by suitably adjusting the spatial orientation of the rollers such that while a roller related to pump 5 produces a positive pulse a corresponding roller related to pump 14 also produces a positive pulse, and while a roller related to pump 5 produces a negative pulse a corresponding roller related to pump 14 also produces a negative pulse. An increase in the amplitude of the 'net pressure pulse' is associated with an increased turbulence inside the cavity. This increased turbulence can be beneficially utilized in reducing the effect of concentration polarization in membrane filtration systems and this concept has been discussed in this manuscript. However in the 'system of pump synchronization' just described the flow rates of the inflow and the outflow pumps cannot be altered independent of each other and if the cavity pressure needs to be varied without changing pump RPM' s then the same is possible only varying the diameter D of the constriction site 8.

A method to dampen the pressure pulsations of a peristaltic pump by a 'syringe system' based active process The 'system of pump synchronization' discussed in the previous paragraph helps in dampening or accentuating the cavity pressure pulsations created by the two peristaltic pumps. However such system of attaching the two peristaltic pumps on a single common driving shaft is practically difficult and it does not allow the two pumps to be run independently of each other thus an easier method of dampening the pressure pulsation of a peristaltic pump is being proposed and the same shall henceforth be referred to as 'pressure pulse dampening system' while the former method is being termed as 'system of pump synchronization'.

Referring to figure 4 the fluid pressure, such as at a point 6, is pulsatile in nature because the peristaltic pump 5 constantly pushes fluid via its outlet end in a pulsed manner and not in a continuous manner. Hypothetically assuming that the pump 5 rotates at fixed RPM then in that case the frequency of such pulsations would remain uniformly the same all through the operation of the pump. If a graph is plotted for the said pulsations, by relating the fluid pressure to the 'Y' axis and the time to the 'X' axis, then such graph would have a uniform shape having positive and negative pressure swings of a predictably fixed amplitude and fixed frequency. It is to be noted that as the pump RPM is increased the frequency as well as the amplitude of the said pressure swings also tend to increase. The said pulsations are produced because each time any one roller of the peristaltic pump comes in apposition with a fixed point, for example the outlet end of the peristaltic pump, some fluid is pushed out from the outlet end of the pump in the form of a bolus. The wave form of such pulsations need not be sinusoidal, but for the sake of an easier understanding let the said waveform be hypothetically assumed to be sinusoidal in nature. As already stated, if the pump RPM increases then along with the frequency, the amplitude of the said waveform also increases. When the pump 5 rotates in the direction of the curved arrow fluid tends to accumulate in tube 9 and in tube 7 between points 6 and 8, and let this cavity consisting of tube 9 and the said part of tube 7, into which the fluid tends to accumulate, be termed as 'fluid accumulation region'. In physical terms the said pressure pulsations are produced because the fluid tends to accumulate or deplete in the 'fluid accumulation region' in the form of regular pulses wherein each pulse corresponds to a fixed volume of fluid pushed (or pulled out) by a roller into the 'fluid accumulation region' in the form of a bolus of fluid. Thus the motion of each roller would correspond to one complete sinusoidal pressure wave. The movement of a single roller in relation to a fixed point such as the outlet end of the pump can be hypothetically divided into three parts, that is, part one when the roller approaches the said point, part 2 when the roller is in apposition with the said point and part 3 when the roller moves away from the said point. Let the parts 1, 2 and 3 be collectively termed as 'single roller movement' and the time taken to accomplish the said 'single roller movement' be termed as 'single roller time'. Assuming the pressure waveform to be a sinusoidal curve, each 'single roller movement' corresponds to one complete sinusoidal pressure waveform consisting of a positive pressure surge followed by a negative pressure surge or vice versa. Also the time period of the assumed sinusoidal wave form would be equal to 'single roller time'. If during the positive pressure surge an adequate volume of fluid is removed from the 'fluid accumulation region' and during the negative pressure surge the same adequate volume of fluid is again added back into the 'fluid accumulation region' the sinusoidal nature of the pressure waveform could get dampened and the resultant waveform would get transformed into an almost straight line curve. The resultant waveform could theoretically be an absolute straight line if the wave form associated with the said process of adding and removing adequate volumes of fluid from the 'fluid accumulation region' absolutely resembled with the wave form produced as a result of the pulsatile flow of the peristaltic pump and the phase difference between the two waves was exactly 180 degrees however this may not be achieved in practical situations. However a substantial dampening of the resultant waveform could be practically achieved if a syringe system was synchronously coupled with the inflow peristaltic pump 5 and the single outlet end of the said syringe system was connected with the 'fluid accumulation region'. Referring to figure 8, this figure is the same as figure 4 except that a syringe system 38 has been included. The syringe system 38 consists of a piston 39 denoted by a shaded area. The piston 39 moves up and down inside a cylinder 43 while making a watertight contact with the inner walls of this cylinder 43. One end of a straight rod 40 is connected to the piston while the other end of this rod 40 is connected to a coupling mechanism 37 housed on a common shaft 36. The coupling mechanism 37 and the peristaltic pump 5, both are attached on to a common shaft 36. The coupling mechanism 37 is so designed that it converts the rotary motion of the shaft 36 into a linear up down motion of rod 40 which is ultimately manifested as an up down movement of piston 39 inside the cylinder 43. The up down motion of the rod 40 is denoted by arrows 41 and 42. Thus the shaft 36 is a common shaft which mechanically operates both, pump 5 as well as the syringe system 38. The direction of rotation of the shaft 36 is denoted by a curved arrow located at the right end of the shaft 36. The syringe system 38, as the name suggests, resembles a hypodermic syringe used for giving injections to patients. Obviously, the syringe system 38 has only one single opening 44. A tube 45 extending between the opening 44 and the inflow tube 10 connects the syringe system to the inflow tube 10. Tube 10 is a part of the said 'fluid accumulation region' described in this paragraph. Thus the syringe system can be considered to be connected with the said 'fluid accumulation region'. The opening 44 can be referred to as an Outlet end' or an 'inlet end' because the syringe system can push as well as pull fluid from the 'fluid accumulation region'. However for the sake of convenience henceforth the opening 44 shall be termed as the outlet end of the syringe system 38. The coupling mechanism 37 is so designed that the vertical movements of the syringe system can be accurately synchronized with the rotary motion of the peristaltic pump 5. The piston 39 can move up>down>up or down>up>down, depending upon the initial position of the piston at the start of the motion and let each such movement of the piston be termed as a 'complete piston movement'. The coupling mechanism 37 is so designed that while the peristaltic pump 5 rotates by 360 degrees the syringe system correspondingly exhibits 'complete piston movements' which are equal to the number of the rollers of the peristaltic pump. Thus for a peristaltic pump which has three rollers then for each 360 degrees rotation of the peristaltic pump the syringe system exhibits three 'complete piston movements' while for a peristaltic pump with four rollers four 'complete piston movements' would occur for each 360 degree rotation of the peristaltic pump. The syringe system is synchronized with the peristaltic pump via the coupling mechanism 37 in such manner that while a roller of the peristaltic pump produces a positive pressure pulse the syringe system extracts fluid out from the 'fluid accumulation region' and while the same roller produces a negative pressure pulse the syringe system pushes an equivalent volume of fluid back into the 'fluid accumulation region'. In order to dampen the pulsations of the peristaltic pump, besides mechanically synchronizing the syringe system with the peristaltic pump the volume of fluid pulled in of pushed out of the syringe system corresponding to each upward or downward movement of the piston also has to be adjusted accurately, and the same may be done manually by a 'hit and try method'. The volume of fluid pulled in or pushed out by the syringe system depends upon the linear movement excursion of the piston 39. Also the magnitude of the downward piston excursion is equal to the magnitude of the upward piston excursion, thus the volume of fluid pushed out is equal to the volume of fluid pulled in during each downward or upward movement. Thus the coupling mechanism 37 has two functions, synchronization of the syringe system with the peristaltic pump and adjusting the volume of fluid pulled in or pushed out by the syringe system for each upward or downward movement of the piston. The synchronization and the determination of the said volume to be pushed out or pulled into the syringe system are done manually such that a substantial dampening of the pressure pulsations is achieved and once this is achieved the synchronization at the level of the coupling 37 is never again disturbed and the volume of fluid pulled in or pushed out of the syringe system for each movement excursion is also not changed thereafter. After the coupling 37 is adjusted with respect to synchronization and with respect to the volume of fluid to be pulled in and pushed out, the peristaltic pump pulsations shall continue to remain dampened independent of the peristaltic pump RPM and the nature of rotation, that is fixed or variable RPM. In simpler terms the peristaltic pump pulsations would continue to remain dampened by the same magnitude even at variable RPM. Also the point at which the syringe system 38 is connected to the said 'fluid accumulation region', for example at the inflow tube 10, then the position of such a point should also not be changed thereafter because this may bring about a phase difference between the waveform related to the peristaltic pump pulsations and the waveform related to the syringe system pulsations, thus the resultant dampening could no longer be satisfactory. Also preferably the outlet tube 45 of the syringe system should be connected as close to the outlet end of the inflow peristaltic pump as possible.

The coupling 37 can be compared to some extent with the conventional CAM system present in automobile engines. Any specific mechanical design for the coupling 37 is not important, it is the resultant function of the coupling 37 with respect to the piston movement, as already described, which is important. The coupling 37 can have many mechanical designs. Figure 9 shows one such possible mechanical design for the coupling 37. In figure 9 a small length of the common shaft 36, which is related to the coupling 37, has been made of triangular shape as seen in its cross sectional view and the same is labeled as 49. Let this triangular part 49 be termed as the 'piston coupler'. The edges of the piston coupler are shown sharp however they could preferably be rounded to suit various operational needs. Similarly the size of the 'piston coupler' could also be increased or decreased in order to decrease or increase the volume of fluid displaced by the cylinder during a downward or upward movement of the piston. The central axis point of the 'piston coupler' is denoted by point 48. In case the dimensions of the 'piston coupler' are chosen to be relatively larger than the dimension of the common shaft 36, the point 48 could also represent the point at which the common shaft 36 passes through the 'piston coupler' and in such a situation the 'piston coupler' 49 could be manually rotated on the common shaft 36 in a clockwise or anti clockwise direction and then locked mechanically at a position which provides the most accurate synchronization. The springs 46 and 47 extending between the inner walls of the cylinder and the piston exert a constant and substantially large upward pull on the piston 39 which causes the rod 40 to constantly be in apposition with the 'piston coupler' 49. The springs can be one or more than one in number and the springs can also be substituted by any other mechanical means also which provide an active upward movement of the piston. The 'piston coupler' 49 is assumed to be able to apply a substantially large downward force on the piston 39 via rod 40 such that a corresponding positive fluid pressure inside the cylinder can be totally neglected in the face of the said large substantial downward force. Similarly the springs 46 and 47 are capable of pulling up the piston with a substantially large force such that a corresponding negative fluid pressure inside the cylinder could be totally neglected. The idea is that the downward movement of the piston should not be aided by the negative pressure pulse inside the cylinder; this downward movement should be an active movement for which energy is to be derived from the springs from the shaft 36. Similarly the upward movement of the piston should not be aided by the positive pressure pulse inside the cylinder; this upward movement should be an active movement for which energy is to be derived from the springs 46 and 47 or from the shaft 36 if suitable mechanical provision corresponding to the active upward movement of the piston has been provided in the coupling 37.

It is important to note that it is not mandatory to use the said 'pressure pulse dampening system' with a peristaltic pump only as, with suitable mechanical modifications, the 'pressure pulse dampening system' could be used beneficially with any type of a positive displacement pump.

The 'pressure pulse dampening system' could also be a mechanism like the 'piston coupler' shown in figure 9 whose rounded edges could directly impinge on a suitable area situated on the outer surface of the 'fluid accumulation region' in a uniform synchronized manner, as described, such that this results in continuous uniform synchronized variations in the total volume capacity of 'fluid accumulation region'. The said suitable area on the outer surface of the 'fluid accumulation region' could be a membrane consisting of a strong resilient polymeric material having an adequate elasticity. The said membrane should also be sufficiently thick and should have an adequate strength and elasticity such that an outward movement of such membrane, a movement related to the upward pull by the said springs, applied a substantially large force which could negate the effect of the magnitude of pressure and the magnitude of the pressure variations in the 'fluid accumulation region'. The said 'pressure pulse dampening system' could also be used to increase the amplitude of the pressure pulsation associated with a peristaltic pump. For achieving the same the said syringe system has to be so synchronized with the corresponding peristaltic pump such that the when a roller of the peristaltic pump creates a positive pressure pulse the piston of the syringe should move down in order to create a positive pressure pulse. In this manner the amplitude of the said pressure pulsations can be accentuated. The increased turbulence can be beneficially utilized in reducing the effect of concentration polarization in membrane filtration systems.

A 'pressure pulse dampening system' presently being described for the inflow pump 5 should, preferably, also be installed on the inlet side of the outflow peristaltic pump 14 in an exactly similar manner as already described. Thus the said dampening is possible for both, inflow and outflow pumps or for only one single pump, the inflow or outflow one. Obviously the overall increase or decrease in the amplitude of the pressure pulsations as perceived inside the cavity 18 shall be more if the said dampening is done at the level of both the pumps because the pressure pulsations from both pumps travel to the cavity 18. It is also to be noted that 'pressure pulse dampening system' is different from the 'system of pump synchronization' accomplished by housing the two peristaltic pumps on to a single common shaft, because in the 'pressure pulse dampening system' both the peristaltic pumps are housed on separate shafts. The 'pressure pulse dampening system' and the 'system of pump synchronization' can also be utilized simultaneously but in that case both the peristaltic pumps shall have to be attached on to the same common driving shaft. In figure 1 the inflow 38 and the outflow 55 syringe systems have been shown synchronized with the inflow and outflow peristaltic pumps 5 and 14 respectively. In the outflow syringe mechanism the common shaft houses the coupling 51 which moves the piston 54 via shaft 63 inside the cylinder 64 whose outlet opening 56 is connected to the outflow tube 12 via tube 57. The coupling system shown in figure 9 would be applicable to this outflow syringe system also.

The 'pressure dampening system' described in the present invention is an active pressure dampening system and not a passive dampening system like the conventional fixed volume expansion chambers filled with a gas or a compressible liquid. The Applicants have realized that only active pressure dampening systems as discussed above provide substantial dampening to the pressure pulsation caused by the peristaltic pumps and any system of passive pressure dampening is not as efficient. The described active 'pressure dampening system' can also help in increasing the amplitude of the pressure pulsations inside the cavity in a very efficient and predictable manner. Also the dampening efficiency of such a 'pressure dampening system' remains the same for any pump RPM and pressure P. Mathematical relationship between Rl, R2 and P

Via experimental and mathematical means a relationship has been derived between Rl, R2 and P and equation for the same is as follows: KP = (R1-R2)² where, Rl = inflow rate, R2 = outflow rate, P = cavity pressure and K = constant. Besides other factors the value of the constant K also depends upon the diameter D at the constriction site 8. Thus with the said other factors remaining same if the value D is not altered then the value of the constant K also remains unchanged. Determination of the instantaneous real time permeate flux rate Let it be hypothetically assumed that fluid is escaping or is being added to the cavity at a rate R3. Again by experimental and mathematical means a relation has been derived between Rl, R2, P and R3. The equation for the said relation is as follows:

KP = (R1-(R2+R3))² where, Rl = inflow rate, R2 = outflow rate, P = cavity pressure, K = constant and R3 = the real time instantaneous rate at which fluid is being removed or added to the cavity. In a membrane filtration system like reverse osmosis the value R3 denotes the instantaneous real time rate at which permeate is being formed in a membrane system like reverse osmosis. The value R3 divided by the total membrane area gives the 'permeate flux rate'. Thus R3 is an accurate indicator of the 'permeate flux rate'. In practical situations the variations in the permeate flux rate are of a very small magnitude and occur over a substantial period of time but the same can also be accurately detected by the system of the proposed invention.

Use of the proposed invention in membrane filtration systems

Referring to figure 10, figure 10 is the same as figure 1 except that in figure 10 the cavity 18 has been substituted by a reverse osmosis system 72. The feed chamber 65 and the permeate chamber 66 are separated by a semi permeable membrane 67. The contaminated feed fluid carrying dissolved solutes enters the feed chamber 65 via the inflow tube 10 attached at the inlet opening 68 of the feed chamber while the 'concentrate fluid' is removed via the outflow tube 12 attached at the outlet opening 69 of the feed chamber 65. As a result of this a pressure P is generated inside the feed chamber. If P is greater than the osmotic pressure then reverse osmosis takes place and the feed fluid transported through the semi permeable membrane 67 accumulates in the permeate chamber 66. The purified permeate fluid drains out of the permeate chamber via tube 71 which is shown attached to the permeate chamber at point 70. The permeate chamber can be at atmospheric pressure or at an allowable higher pressure. Referring to figure 10 the controller can be programmed in multiple ways in order to enhance the efficiency and accuracy of the reverse osmosis system 72. The controller can be programmed to work at desired values R2 and P while the value R3 continuously determines and displays the real time permeate flux rate by the help of the relation KP = (R1-((R2+R3))². The controller could also be programmed to maintain a desired permeate flux rate R3 and at a desired outflow rate R2. In this case the controller automatically determines and establishes an appropriate value for Rl at which the desired R3 is maintained but in this situation the value P cannot be a desired value. The controller can also be programmed to operate the system at desired R3 and P but in this case a desired value has to be chosen for Rl and the controller automatically determines and establishes an appropriate value for R2. As already discussed the turbulence inside the permeate chamber 65 can also be increased or decreased, as desired, by the help of the 'pressure pulse dampening system' and the 'pump synchronization'. If turbulence was raised to some optimum level the concentration polarization could be minimized and in this manner the permeate flux rate R3 could be maximized for any R2 and P. USE OF THE INVENTION IN MODULATING AND MONITORING CHEMICAL REACTIONS

It has already been discussed in the heading 'Background of the invention' that the present invention is also a system of pressurizing a cavity housing a chemical reaction under dynamic state of continuous flow irrigation. Also the real time relative density variations occurring inside the cavity under the said dynamic conditions is constantly gauged by the system of the proposed invention. The importance of determining the real time progress or extent of completion of a chemical reaction as a function of the said real time relative density variations has also been discussed in the past sections. The basic functioning of the invention in the present context of 'modulating and monitoring chemical reactions' has been discussed in detail in the previous sections of this manuscript in reference to figures 1 to 9. In previous sections of this manuscript related to 'reverse Osmosis' a mathematical expression KP = (R1-R2-R3)² had been derived wherein Rl = inflow rate, R2 = outflow rate, P = cavity pressure, K = constant and R3 = the real time instantaneous rate at which fluid is being added or removed from the cavity. However in context with 'chemical reactions' the value R3 does not relate to any fluid which escapes via the cavity walls while R3 simple relates to numerical value which can be beneficially used for gauging the instantaneous real time relative density variations occurring inside the cavity.

Gauging the real time rate of density variations inside the cavity

Let us assume an imaginary chemical reaction A+B*C+D which occurs inside a closed cavity having a fixed volume. Now as this reaction occurs in any direction, right or left, the cavity pressure would tend to vary depending overall density of the reactant product mixture and also depends on whether the reactant product mixture tends to occupy greater of lesser volume. Obviously in such a case the overall extent of completion of this reaction at any given moment of time is a function of the cavity pressure, assuming that other factors remain unchanged. Via suitable experimental and analytical means a mathematical correlation ship could be derived between the cavity pressure and the extent of completion of this reaction at any given moment of time. In this manner it could be possible to gauge in real time the extent of completion of this reaction as a function of the pressure P. However if such a reaction were to occur under dynamic conditions of continuous flow irrigation then it would not be possible to gauge in real time the overall extent of completion of the reaction in the manner just described, because the reactants and products continuously enter and exit from the cavity. The proposed invention provides a simple solution to this problem.

An 'Optimum Completion' is an important industrial requirement for a chemical reaction Efficiency or alternatively achieving a minimum final percentage completion is one of the important industrial requirements for a chemical reaction. Let it be assumed that a hypothetical chemical reaction A+B^C+D occurs inside a cavity under dynamic conditions of continuous flow irrigation. It is obvious that due to continuous flow irrigation some volume of reactants continuously enter the cavity while some volume of products is constantly being removed from the cavity. In such case it important to ensure that the fluid removed from the cavity outflow side should contain the product molecules in at least some desired minimum concentration, otherwise the chemical reaction may not be considered efficient from an industrial and economic point of view. This is possible only if the chemical reaction inside the cavity is made to occur at some desired optimum rate, and in a predictable manner. In the next paragraph it shall be explained as to how the system of the proposed invention can be used for gauging in real time the rate of the said chemical reaction as a function of the real time density variations. Determination of the real time rate of density variation

In continuation with the previous paragraph, the density of products C 4- D can be greater or lesser than the density of the reactants A + B. If the density of the products is lesser than the density of the reactants then the contents of the cavity tend to occupy more volume and this is reflected as an increased in the pressure P, and R3 in this case shall have a negative numerical value or a reducing value. Alternatively if the density of the products is more than the density of the reactants then the contents of the cavity tend to occupy a smaller volume and this is reflected as a decrease in the pressure P, and R3 in this case shall have a positive numerical value. In context with the previous sections of the manuscript the negative and positive values for R3 can be hypothetically equated to a situation wherein some fluid in being added or removed from the cavity. Coming back to the main discussion, the overall rate of density inside the cavity is a function of the imaginary value R3. Referring to the equation KP = (Rl- R2-R3)² the values K, P, Rl and R2 are always known, and by substituting these four known values in the said equation with or without the help of the controller the imaginary value R3 could be constantly determined in real time. The real time rate of change of density is a function of real time rate of change in the magnitude of the imaginary value R3. Thus the value R3 can be used for gauging the real time rate of density variations inside the cavity. Determining in real time rate of a chemical reaction as a function of the real time rate of density variation Referring back to the hypothetical reaction A+B^C+D the product C+D is formed only if the reactant molecules A and B react with each other, and also the density of the product and the density of the product-reactant mixture may not be the same. In this context the real time rate of the chemical reaction is being taken as a function of the real time rate of density variation R3. Gauging in real time the overall extent of completion of a chemical reaction

Let us again refer to the hypothetical reversible reaction A+B^C+D occurring inside a closed cavity under continuous flow irrigation. In this reaction the overall extent of completion of the reaction at any given moment of time would depend upon rate of the chemical reaction and the time duration for which the product-reactant mixture was subjected to the cavity conditions. The reaction rate depends upon various 'conditions' like pressure, temperature, pH, flow rate at reaction site, turbulence at the reaction site and catalyst. For a given set of the said 'conditions' a 'relationship' could be derived between R3 and the overall extent of completion of a chemical reaction in real time. The said 'relationship' could be derived via experimental and analytical means. In the next paragraph it shall be explained how to modulate a chemical reaction for the purpose of achieving a desired percentage completion or a desired overall extent of completion of the chemical reaction. Modulating chemical reactions

Let it be assumed that a chemical reaction A+B^C+D is being carried out. Via experimental means an optimum value of R3, which would provide a desired percentage completion for the reaction at desired R2 could be determined. In such case if the rate of the reaction were to be a function of P then on the basis of the equation KP = (R1-R2-R3)² the controller could be programmed to always maintain the said desired optimum value R3 by adjusting Rl in order achieve some unknown hypothetical value P while R2 remain same. Similarly under another set of industrial requirements R3 could also be varied as a function of P by appropriately varying Rl.

Determining in real time the depletion or consumption of a catalyst Many chemical reactions are influenced by catalysts. As the catalyst depletes the chemical reaction may also slow down. With other factors remaining constant the variation in the value R3 may accordingly indicate the depletion or consumption of a catalyst. The rate of depletion or consumption of a catalyst is obviously a function of R3. Via experimental means a relationship could be derived between R3 and the real time rate of consumption of a catalyst. USE OF THE INVENTION EV TRANSPORTING FLUIDS THROUGH PIPES A major part of the discussion related to the role of the invention in transporting fluids through pipes has already been stated under the heading entitled ' A novel and efficient system to transport fluids through a pipe' under ' Background of the invention'. Referring to figure 3 an experiment was conducted wherein the cavity 18 was replaced by a tube 25 meters long having an inner diameter of 6 mm. The out flow pump 14 was removed and the inflow pump 5 was made to push water via the said 25 meter long tube at a flow rate Rl being equal to 820 ml/min (the constriction site 8 being fully occluded); it was found that the water pressure at point 6 was 150 mm Hg while the pressure P at the end of the tube was zero, that is atmospheric because this distal end opened directly into the atmosphere. Next, the out flow pump 14 was connected and was made to run at 820 ml/min while the inflow pump 5 was made to run at approximately 820.25 ml/min and the opening of the constriction site was made as small as practically possible. Such system was made to run for 12 hours at the end of which it was observed that the pressure at [point 6 dropped to approximately 100 mm Hg while the pressure at the distal end of the outflow tube 12 adjacent to the inlet end of the outflow pump 14 was minus approximately 50 mm Hg. Obviously by the system of the proposed invention, that is by adding the outflow pump 14, a reduction of 50 mm Hg pressure was achieved at the proximal and distal ends of the 25 meter pipe transporting water for the same flow rate of 820 ml/min. All through this experiment intermittent micro drops kept emitting via the constriction site 8 as Rl was kept minutely greater than R2, but for all practical purposes Rl in this case can be considered to be equal to R2. It this experiment it was also observed that all through the 12 hours the pressures as measured at multiple at multiple locations along the length of the pipe remained constant with time. In physical terms, the system of the proposed invention as depicted by this experiment is a system wherein two positive displacement pumps attached at two ends of a pipe can work simultaneously for indefinite time in order to transport fluid through the pipe such that pressure at any point along the length of the pipe remains unchanged for indefinite time and a predictable reduction in pressure is achieved at any location in the pipe for the same flow rate in context with the prior art systems which incorporate a single pump attached installed on either end. The advantages of the embodiment discussed in the previous paragraph are immense. This implies that by the system of the proposed invention fluid can be transported via a pipe at an increased flow rate without any associated increase in the pressure values at the proximal and the distal ends of the pipe. This in turn implies enhancing the mechanical fluid carrying efficiency of the pipe. In simple terms it means that with the system of the proposed invention a mechanically weak pipe need not be replaced by a stronger pipe if fluid at an increased flow rate needs to be passed through it. This has important attached economic advantages since it allows an increased flow rate of valuable fluids like petroleum and gas through the same weak pipes.

The concept of 'null point point' has been described in the previous sections. 'Null point' being the point of atmospheric pressure, neutral pressure or zero pressure. A predictable location of the null point provided by the system of the proposed invention allows optimization in construction cost of a long pipeline if the pipe strength is decided keeping in mind the positive, neutral or positive pipe pressures and also the position of the null point. It is needless to add that that a predictable reduction of fluid pressure at any point along the entire length of the pipe is an important feature of the invention. The substantial pressure dampening achieved by the syringe system (an embodiment of the invention) further helps in fixing the 'null point' at a known location in predictable manner. To actively dampen pressure pulsations of positive displacement pumps without using any feed back mechanism. The proposed invention also provides a useful and novel system which dampens the pressure pulsations created by positive displacement pumps in an active manner but without using any feedback mechanism and without utilizing the conventional pressure dampening compression chambers. The said dampening system comprises of a single outlet syringe mechanism, the piston of the same being coupled synchronously to the positive displacement inflow and or outflow pump through a coupling means and a single outlet end of the said syringe mechanism being connected to the out flow or inflow side of the said two pumps respectively. This syringe system based pressure dampening system has been described in great detail in the previous section entitled ¹A method to dampen the pressure pulsations of a peristaltic pump by an active process without any feedback mechanism' under the section under the basic heading 'Use of the invention in reverse osmosis'. The said syringe system has be incorporated in figures 1, 8, 9 and 10 but for the sake of brevity the detailed functioning of the same shall not be described again.

Such a syringe system based pressure dampening system has important uses related to membrane systems, chemical reactions and fluid transport. Besides these stated three uses such embodiment in also beneficial where fluid needs to be pulled from great depths such as oil wells and where needs to be pumped to great heights such as a water storage tank on the roof top of a multi storied building or situated over a mountain top. In such cases like pumping oil positive displacement pumps are often used and the pumping efficiency could be considerably enhanced by incorporating the active pressure dampening system provided by the system of the proposed invention. The present invention is a unique and an ideal system to pressurize various types of industrial cavities such that the cavity pressure and the cavity flow rate are absolutely independent of each other without incorporating any constriction site or a restriction valve over the outflow side of the cavity. There is no prior art system which incorporates two positive displacement pumps installed on an inlet and an outlet end of an industrial cavity such that the two pumps run simultaneously at fixed flow rates for indefinite time in order to create and maintain any desired cavity pressure which is absolutely independent of the cavity flow rate and without incorporating any constriction site on the cavity out flow side, such that the real time rate of diffusion or escape of fluid via the cavity walls is also known. CONCLUSION The proposed invention is novel and unique. The invention is advantageous offers obvious advantages in long distance fluid transportation, in membrane filtration systems, in monitoring various chemical reactions and in active pressure dampening of positive displacement pumps without any feed back mechanism.

Claims

We Claim:

1. A continuous fluid flow irrigation system for transporting fluid across an industrial cavity under substantially constant pressure and reduced turbulence, said system comprising: a fluid source reservoir containing a fluid meant for being transported across the industrial cavity; a fluid supply conduit tube connecting the fluid source reservoir to an inlet end of a positive displacement inflow pump and an outlet end of the said inflow pump being connectable to an inflow port of the industrial cavity for pumping the fluid at a controlled flow rate into the industrial cavity, the flow rate of the inflow pump being termed as the inflow rate; an outflow port of the industrial cavity being connectable to an inlet end of a positive displacement outflow pump for removing the fluid from the industrial cavity at a controlled flow rate, the flow rate of the outflow pump being termed as the outflow rate, and a housing tube having a controllable constriction site is being provided between an inflow region and the inflow port of the industrial cavity, the inflow region comprising of the fluid source reservoir, the fluid supply conduit tube and the atmosphere; such that the housing tube by-passes the inflow pump and provides a route for any excess fluid present in the industrial cavity to bypass the inflow pump and go back to the inflow region when the inflow and the outflow pumps are operated at substantially fixed flow rates thereby maintaining the pressure inside the industrial cavity at a stable value and minimizing turbulence inside the industrial cavity.

2. The continuous fluid flow irrigation system as claimed in claim 1, wherein the fluid source reservoir containing the fluid is maintained at atmospheric pressure or at a pressure greater than the atmospheric pressure or at a pressure lower than the atmospheric pressure.

3. The continuous fluid flow irrigation system as claimed in claim 1, wherein a proximal open end of the fluid supply conduit tube is connected to the fluid source reservoir and a distal end of the tube is connected to the inlet end of positive displacement inflow pump.

4. The continuous fluid flow irrigation system as claimed in claim 3, wherein the proximal open end of the fluid supply conduit tube is constantly and completely immersed in the fluid source reservoir.

5. The continuous fluid flow irrigation system as claimed in claim 1, wherein an outlet end of the inflow pump is connectable to the inflow port of the industrial cavity through an inflow tube.

6. The continuous fluid flow irrigation system as claimed in claim I₅ wherein the positive displacement inflow pump is selected from the group comprising peristaltic pump, piston pump, gear pump, diaphragm pump and plunger pump.

7. The continuous fluid flow irrigation system as claimed in claim 6, wherein the positive displacement inflow pump is a fixed flow rate pump, whose flow rate could be varied from one fixed flow rate value to another fixed flow rate value, or a variable flow rate pump and the same is a peristaltic pump.

8. The continuous fluid flow irrigation system as claimed in claim 1, wherein the housing tube is releasably provided between the inflow region and the inflow port of the industrial cavity to enable replacement of the housing tube with yet another housing tube having a different diameter at the constriction site to suit the operational need of the industrial process.

9. The continuous fluid flow irrigation system as claimed in claim 1, wherein a proximal end of the housing tube is connected to the fluid supply conduit tube near its distal end close to the inlet port of the inflow pump.

10. The continuous fluid flow irrigation system as claimed in claim 9, wherein the proximal end of the housing tube empties directly into the fluid source reservoir and is constantly and completely immersed in the fluid source reservoir.

11. The continuous fluid flow irrigation system as claimed in claim 9, wherein the proximal end of the housing tube opens into the atmosphere.

12. The continuous fluid flow irrigation system as claimed in claim 1, wherein a distal end of the housing tube is connected to the inflow port of the industrial cavity or to the inflow tube near its proximal end close to the outlet end of the inflow pump.

13. The continuous fluid flow irrigation system as claimed in claim 1, wherein the housing tube is provided with a clamping means at the constriction site to enable the user to vary the diameter of the housing tube at the constriction site to suit the operational needs of an industrial process.

14. The continuous fluid flow irrigation system as claimed in claim 1, wherein an inflow pressure transducer is connected directly to the inflow port of the industrial cavity or is connected directly to the industrial cavity or is located anywhere in the inflow tube between the outlet end of the inflow pump and the inflow port of the industrial cavity.

15. The continuous fluid flow irrigation system as claimed in claim 14, wherein the inflow pressure transducer is located sufficiently away from the cavity site, near the outlet end of the inflow pump from the practical point of view, such that the fluid pressure measured by the same is almost equal to the fluid pressure inside the cavity.

16. The continuous fluid flow irrigation system as claimed in claim 1, wherein the outlet port of the industrial cavity is connected to an inlet end of the positive displacement outflow pump via an outflow tube.

17. The continuous fluid flow irrigation system as claimed in claim 1, wherein an outflow pressure transducer is further connected between the outlet port of the industrial cavity and the inlet end of the positive displacement outflow pump or between a proximal end of the outflow tube and the inlet port of the positive displacement outflow pump or directly to the industrial cavity.

18. The continuous fluid flow irrigation system as claimed in claim 1, wherein the positive displacement outflow pump is selected from the group comprising peristaltic pump, piston pump, gear pump, diaphragm pump and plunger pump.

19. The continuous fluid flow irrigation system as claimed in claim 1, wherein the positive displacement outflow pump is a fixed flow rate pump, whose flow rate could be varied from one fixed flow rate value to another fixed flow rate value, or a variable flow rate pump and the same is a peristaltic pump.

20. The continuous fluid flow irrigation system as claimed in claim 1, wherein an outlet end of the positive displacement outflow pump is connectable to a fluid collecting container.

21. The continuous fluid flow irrigation system as claimed in claim 20, wherein the outlet end of the positive displacement outflow pump is connectable to the fluid collecting container through a fluid disposal tube.

22. The continuous fluid flow irrigation system as claimed in claim 1, further comprising a controller means electrically coupled to at least one of the inflow pressure transducer, the outflow pressure transducer, the transducer attached to the cavity, the inflow pump or the outflow pump.

23. The continuous fluid flow irrigation system as claimed in claim 1, further comprising a housing tube having a variable size constriction site being provided between the outflow port of the industrial cavity and an outflow region, the outflow region comprising of the fluid disposal tube, the fluid collecting container and the atmosphere.

24. The continuous fluid flow irrigation system as claimed in claim 1, wherein the distal end of the housing tube is connected to the fluid disposal tube or the fluid collecting container or the distal end of the housing tube opens directly into the atmosphere.

25. The continuous fluid flow irrigation system as claimed in claim 1, wherein the inflow and the outflow positive displacement pumps are coupled to a common shaft for synchronously operating the two pumps.

26. The continuous fluid flow irrigation system as claimed in claim 1, wherein the housing tube is provided with an electromechanical device, a solenoid, to enable the controller to vary the diameter of the constriction site.

27. The continuous fluid flow irrigation system as claimed in claim 1, wherein if the inflow and the outflow pumps are coupled to the common shaft, the housing tube is provided with the controller controlled solenoid for varying the diameter of the constriction site.

28. The continuous fluid flow irrigation system as claimed in claim 1, wherein an inflow pressure pulsation dampening means is connected to the inflow port of the industrial cavity or to the inflow tube for dampening the pressure pulsations inside the cavity created by the positive displacement inflow pump.

29. The continuous fluid flow irrigation system as claimed in claim 1, wherein the inflow pressure variation dampening means comprises a pressure dampening fixed volume expansion chamber.

30. The continuous fluid flow irrigation system as claimed in claim 1, wherein the inflow pressure variation dampening means comprises a single outlet syringe mechanism, the piston of the same being coupled synchronously to the positive displacement inflow pump through a coupling means and a single outlet end of the said syringe mechanism being connected to the inflow tube.

31. The continuous fluid flow irrigation system as claimed in claim 1, wherein an outflow pressure pulsation dampening means is connected to the outflow port of the industrial cavity or to the outflow tube for dampening the pressure pulsations inside the cavity created by the positive displacement outflow pump.

32. The continuous fluid flow irrigation system as claimed in claim 1, wherein the outflow pressure variation dampening means comprises a single outlet syringe mechanism, the piston of the same being coupled synchronously to the positive displacement outflow pump through a coupling means and a single outlet end of the said syringe mechanism being connected to the outflow tube.

33. The continuous fluid flow irrigation system as claimed in claim 1, wherein if the inflow and the outflow pumps are operated synchronously by coupling them to the common shaft, the inflow and /or the outflow pressure variation dampening means are optionally operated synchronously by coupling them to the same common shaft.

34. The continuous fluid flow irrigation system as claimed in claim 1, wherein the inflow and the out flow pumps operate simultaneously at fixed flow rates for indefinite time for the purpose of creating and maintaining any desired constant cavity pressure.

35. The continuous fluid flow irrigation system as claimed in claim 1, wherein a bypass tube is provided between the inlet and the outlet ends of the cavity.

36. The continuous fluid flow irrigation system as claimed in claim 35, wherein the bypass tube has a controllable constriction site.

37. The continuous fluid flow irrigation system as claimed in claim 35, wherein the bypass tube has a pressure release valve which opens in case the pressure exceeds a predetermined value.

38. The continuous fluid flow irrigation system as claimed in claim 35, wherein the bypass tube has a unidirectional valve which allows fluid to pass in one particular direction.

39. The continuous fluid flow irrigation system as claimed in claim 1, wherein the said industrial cavity is a pipe meant for fluid transportation, a feed chamber of a membrane filtration system or a cavity housing a chemical a chemical reaction.