SG186589A1 - Continuous liquid feed system and control method thereof - Google Patents
Continuous liquid feed system and control method thereof Download PDFInfo
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- SG186589A1 SG186589A1 SG2012049490A SG2012049490A SG186589A1 SG 186589 A1 SG186589 A1 SG 186589A1 SG 2012049490 A SG2012049490 A SG 2012049490A SG 2012049490 A SG2012049490 A SG 2012049490A SG 186589 A1 SG186589 A1 SG 186589A1
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- Singapore
- Prior art keywords
- liquid feed
- pumps
- syringe type
- type liquid
- pump
- Prior art date
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- 239000007788 liquid Substances 0.000 title claims abstract description 249
- 238000000034 method Methods 0.000 title claims abstract description 10
- 230000007423 decrease Effects 0.000 claims abstract description 5
- 230000003247 decreasing effect Effects 0.000 claims abstract description 4
- 238000007599 discharging Methods 0.000 claims abstract description 3
- 230000001133 acceleration Effects 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 7
- 230000004913 activation Effects 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 230000010349 pulsation Effects 0.000 description 5
- 238000011144 upstream manufacturing Methods 0.000 description 5
- 239000003973 paint Substances 0.000 description 4
- 230000001360 synchronised effect Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B23/00—Pumping installations or systems
- F04B23/04—Combinations of two or more pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B23/00—Pumping installations or systems
- F04B23/02—Pumping installations or systems having reservoirs
- F04B23/025—Pumping installations or systems having reservoirs the pump being located directly adjacent the reservoir
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B23/00—Pumping installations or systems
- F04B23/04—Combinations of two or more pumps
- F04B23/06—Combinations of two or more pumps the pumps being all of reciprocating positive-displacement type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/10—Other safety measures
- F04B49/106—Responsive to pumped volume
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Positive-Displacement Pumps (AREA)
- Reciprocating Pumps (AREA)
- Details Of Reciprocating Pumps (AREA)
Abstract
33CONTINUOUS LIQUID FEED SYSTEM AND CONTROL METHOD THEREOFAbstract of the DisclosureA continuous liquid feed system sucks and pressurizes5 liquid accommodated in a container to be discharged to a demander. The continuous liquid feed system includes: plural pumps which are in communication with the container; valves each of which is provided for each pump and which are arranged between the pumps and the container;10 motors each of which is provided for each pump to drive the same; and a controller which controls the motors and the valves. When discharging a predetermined flow quantity with one pump, the controller allows the other pump to perform a suction operation or stops the other15 pump, decreases the flow quantity discharged by the one pump in a predetermined period from the time the one pump starts to discharge and in a predetermined period immediately before completion of the discharge, and allows the other pump to discharge only the decreased flow20 quantity. It is possible to suppress variations in the feeding amount of liquid even when a pump used for a liquid feed operation is switched to another while preventing an interruption in backflow.
Description
CONTINUOUS LIQUID FEED SYSTEM AND CONTROL METHOD THEREOF
The present invention relates to a continuous liquid feed system and a control method thereof, and particularly to a continuous liquid feed system having liquid feeding units such as syringe type liquid feed pumps that feed a small amount of 1liguid and a control method thereof.
Syringe type liquid feed pumps and the like are used in many cases to feed a small amount of liquid, for example, at about 10ml/min. In the case of the syringe type liquid feed pumps, if a pressure loss is changed as a result of changing the type of liquid tobe fed and a pipe system, the feeding amount of liquid is not changed and a stable amount of liquid can be fed. Making use of this characteristic, the syringe type liquid feed pumps are used for measurement devices in the chemical fields and the like.
Incidentally, the syringe type liquid feed pump has a structure in which a predetermined amount of liquid accommodated in a syringe is pushed out with a plunger. When a predetermined amount of liguid in the syringe is completely discharged, it is necessary to stop the liguid feeding cnce to suck liquid again. It is obvious that the liquid feeding is stopped during the suction of liquid, and the liguid feeding is interrupted. Accordingly, various methods to prevent the interruption of liquid feeding using two syringe type liquid feed pumps have been proposed.
In a system described in, for example, Japanese Patent
Application Laid-Open No. 2003-293946, two syringe type liquid feed pumps are connected in series to prevent replacement of liquid to be used and pulsation, and an interruption in liquid feeding is suppressed by operating the system in such a manner that when one syringe sucks liquid, the other syringe discharges liquid.
Examples of connecting plural syringe type liquid feed pumps in parallel are described in Japanese Patent Application
Laid-Open No. H8-182952 and Japanese Patent Application
Laid-Open No. 2006-266158. In a sheet coating apparatus described in Japanese Patent Application Laid-Cpen No.
H8-182952, two micro-syringe pumps are connected in parallel.
When one pump sucks from a paint tank, the other pump coats a substrate on a stage with paint. Further, in a syringe type liquid feed pump unit described in Japanese Patent Application
Laid-Open No. 2006-266158, base portions of pistons of syringe type liguid feed pumps are sandwiched between both ends of an oscillation arm. When one piston performs a discharge operation, the other piston performs a suction operation.
Tn a conventional liquid chromatograph described in
Japanese Patent Application Laid-Open No. 2003-293946, a syringe type liquid feed pump on the upstream side and a syringe type liquid feed pump on the downstream side are combined in series, and check valves to prevent backflow of liquid are provided on the inlet side and the outlet side of the syringe type liquid feed pump on the upstream side. The syringe type liguid feed pump on the downstream side feeds liquid while making up for an interruption in liquid feeding from the syringe type liquid feed pump on the upstream side. Specifically, when the syringe type liquid feed pump on the upstream side discharges liquid in the liquid feed pump, the syringe type liquid feed pump on the downstream side sucks liquid to prevent an interruption in liquid feeding. Thus, for the syringe type liquid feed pump on the upstream side, a suction amount by which the syringe type liquid feed pump on the downstream side sucks is included in a discharge amount required as a device, and thus the power of the pump is increased.
Further, the check valves are used to eliminate an interruption in liquid feeding, and the use of the check valves is advantageous in reducing a dead volume amount. However, the cross-sectional area of a flow channel is reduced, and thus there is a possibility that minimal solids deposited in liquid being fed, or fine particles in slurry liquid are included in liquid itself being fed as foreign materials.
Further, in the case of the apparatus described in
Japanese Patent Application Laid-Open Nc. H8-182952 in which the pumps are connected in parallel, a paint operation and a suction operation are alternately executed by switching switch valves connected to the respective syringe type liguid feed pumps. However, the timing of switching the paint operation and the suction operation of the syringe type liquid feed pumps corresponds to the timing of replacing the substrate in the apparatus described in Japanese Patent Application Laid-Open
No. E8-182952. Thus, thisprocess isa so~calledbatchprocess, and continuous liquid supply while switching the pump is not considered.
Further, in the syringe type liquid feed pump unit described in Japanese Patent Application Laid-Open No. 2006-266158, the syringe type liquid feed pumps are connected in parallel to switch a suction operation and a coating operation with an electromagnetic switch valve. In the case of the syringe type liquid feed pump unit described in Japanese
Patent Application Laid-Open No. 2006-266158, when the syringe type liguid feed pump used for the coating operation is replaced, the coating is stopped after changing the nozzle position from the coating pogition once. Specifically, continuous liquid supply is not considered even in the syringe type liquid feed pump unit described in Japanese Patent Application Laid-Open
No. 2006-266158.
The present invention has been achieved in view of the above-described problems of the related art, and an object thereof is to suppress variations in the feeding amount of 5 liguid even when a pump used for a liquid feed operation is switched to another while preventing an interruption in backflow at the time of feeding a small amount of liguid.
Another object of the present invention is to realize a highly-reliable liquid feed system for continuously feeding a constant small amount of liguid.
As a characteristic of the present invention to achieve the above-described objects, provided is a continuous liquid feed system that sucks and pressurizes liquid accommodated in a container to be discharged to a demander, the system including: plural pumps which are in communication with the container; valves each of which is provided for each pump and which are arranged between the pumps and the container; motors each of which is provided for each pump to drive the same; and a controller which controls the motors and the valves, wherein when discharging a predetermined flow quantity to the demander with one pump, the controller allows the other pump to perform a suction operation or stops the other pump, decreases the flow quantity discharged by the one pump in a predetermined period from the time the one pump starts to discharge and in a predetermined period immediately before completion of the discharge, and controls the plural pumps and the valves go as to allow the other pump to discharge only the decreased flow quantity.
In the characteristic, it is preferable that the valves be rotary valves, the plural pumps be plural syringe type liquid feed pumps, and the controller control continuous liquid feeding by switching the discharge and suction operations of the plural syringe type liquid feed pumps tc each other. In addition, it is desirable that the plural pumps be two syringe type liquid feed pumps, and the controller allow the two syringe type liquid feed pumps to alternately repeat an independent discharge operation, and control the discharge operations of the both syringe type liguid feed pumps to be overlapped with each other before and after the independent discharge operation of each syringe type liquid feed pump.
In the characteristic, a flowmeter for detecting the flow quantity of liquid discharged from the pumps and a pressure gauge for detecting the pressure of the liquid may be provided petween discharge parts of the pumps and the demander, a storing unit for storing a control data table of combination patterns between the activation timings and the acceleration/deceleration time of the motors that drive the pumps may be provided at the controller, and the controller may drive the pumps using the control data stored in the storing unit under the conditions that the measurement values of the pressure gauge and the flowmeter are most stabilized.
As another characteristic of the present invention to achieve the above-described objects, provided is a control method of a continucus liquid feed system that sucks and pressurizes liquid accommodated in a container to be discharged to a demander using: two syringe type liguid feed pumps with the same capacity that are in communication with the container; rotary valves each of which 1s provided for each of the two gyringe type liquid feed pumps and which are arranged between the syringe type liquid feed pumps and the container; motors each of which is provided for each syringe type liquid feed pump to drive the same; and a contrcller which controls the motors and the rotary valves, wherein: the two syringe type liquid feed pumps are allowed to alternately perform a suction operation and a discharge operation; when one syringe type liquid feed pump independently performs the suction operation, the other syringe type liguid feed pump is allowed to perform the suction operation, and the other syringe type liquid feed pump is allowed to perform the discharge operation only in a predetermined period immediately before starting the independent operation of one syringe type liquid feed pump and only in a predetermined period before completion of the independent operation; and when the both syringe type liquid feed pumps perform the discharge operation, the one syringe type liquid feed pump is decelerated, and the other syringe type liquid feed pump is accelerated by the amount corresponding to the deceleration of the one syringe type liquid feed pump.
In the characteristic, when the one syringe type liguid feed pump performs the independent discharge operation, it is preferable that the rotary valve connected to the other syringe type liquid feed pump be switched from the discharge side to the suction side, solution be sucked from the container with the other syringe type liguid feed pump, and the rotary valve connected to the other syringe type liguid feed pump be switched from the suction side to the discharge side.
According to the present invention, two syringe type liquid feed pumps are connected in parallel, the rotary valve is attached to each syringe type liquid feed pump, and the discharge operation of one syringe type liquid feed pump is performed before completion of the discharge operation of the other syringe type liquid feed pump. Thus, clogging by foreign materials can be prevented, and variations in the feeding amount of liguid from the syringe type liquid feed pumps caused at the time of switching the valve can be suppressed. Furthermore, it is possible to realize a highly-reliable liquid feed system for continuously feeding a congtant small amount of liquid.
Brief Description of the Several Views of the Drawing
Fig. 1 ig a block diagram of an embodiment of a continuous liguid feed system according to the present invention;
Fig. 2 is a timing chart for showing operations of pumps and valveg provided in the continuous liquid feed system shown in Fig. 1; and
Fig. 3A to Fig. 3C are flowcharts each showing control of the continuous liquid feed system shown in Fig. 1.
Detailed Description cof the Invention
Hereinafter, an embodiment of a continuous liquid feed system according to the present invention will be described using the drawings. Fig. 1 is a block diagram of a continuous liquid feed system 50, Fig. 2 is a timing chart for showing operations of syringe type liquid feed pumps and rotary valves, and Figs. 3 are control flowcharts of the syringe type liquid feed pumps and the rotary valves provided in the continuous liquid feed system 50.
The continuous liquid feed system 50 is divided into a mechanical unit 42 held in a casing, a container 40 which is detachably attached to the inside of the casing and in which liguid to be fed is accommodated, and a control unit 30 that controls the continuous liquid feed system 50. In addition, the mechanical unit 42 includes a liquid feedunit 10 as a central device of the continuous liquid feed system 50, and a piping unit 20 that is located on the downstream side of the liguid feed unit 10.
In the liquid feed unit 10, first and second syringe type liquid feed pumps 18a and 18b are arranged in parallel.
Plungers 12a and 12b are inserted into syringes lla and 1lb of the first and second syringe type liquid feed pumps 18a and 18b, regpectively. Ends of the plungers 12a and 12b opposite to those inserted into the syringes lla and 11b are fixed to slide blocks 15a and 15b of ball screws 14a and 14b, respectively.
The ball screws 14a and 1l4b are driven by motors 13a and 13b, respectively.
Adapters 21a and 21b to be connected to pipes are attached to the discharge side of the syringe type liquid feed pumps 18a and 18b, and the downstream side of the adapters 21a and 21b ig connected to the primary side of rotary valves 22a and 22D.
On the secondary side of the rotary valves 22a and 22b, ones of them are connected to the container 40 through pipes 24a and 24b, and the others are connected to pipes 27a and 27b that are connected to a demander. The pipes 27a and 27b connected to the demander are brought together as one pipe 19 at a piping junction 25 to be connected to the demander (not shown) through a flowmeter 26. The pipes 24a and 24b are also brought together as one pipe 29 at a piping junction 28 to be connected to the container 40.
A pressure gensor 23 is attached in the middle of the pipe 1% connected to the demander on the downstream side of the flowmeter 26. Signals detected by the pressure sensor 23 and the flowmeter 26 are input to a controller 31 such as a personal computer included in the control unit 30 through signal lines
81 and 82. The controller 31 has a storing unit 31a and a computing unit 31b. Data such as a pre-set flow quantity is stored into the storing unit 3la. Input/output devices 32 such as a mouse, a keyboard, and a display are attached to the controller 31. On the basis of the input signals, the controller 31 outputs various commands to the rotary valves 22a and 22b and the motors 13a and 13b for driving the ball screws l4a and 14b through signal line S83 to S6.
Specifically, the plungers 12a and 12b reciprocate in the syringes lla and 11b, respectively, so that liquid sucked into the syringes 1la and 11b from the container 40 through the pipes 24a and 24b is discharged from the pipes 27a and 27b. The plungers 12a and 12b are driven by the motors 13a and 13b as power sources, respectively. At this time, the rotational motion of the motors 13a and 13b is converted into the reciprocal motion by the ball screws l4a and 14b and the slide blocks 15a and 15b.
The adapters 21a and 21b are joints that allow the syringe type liguid feed pumps 18a and 18b with different capacities to be able to be used in the continuous liquid feed system 50, and allow the syringe type liquid feed pumps 18a and 18b with different sizes to be connected to the rotary valves 2la and 21b without leaks, respectively. Specifically, screw holes are provided at mounting portions of the adapters 21a and 21b on the rotary valve 22-side, and the adapters 2la and 21b are fastened to the rotary valves 22 by screws. Luer lock-type connecting ports are provided at mounting portions of the adapters 21a and 21b on the syringe ll-side. Any of syringes 11 with tip ends formed in a luer lock shape that are generally used in the chemical and medical fields can be connected irrespective of capacities. The present invention can be adapted to a variety of liquid feed conditions only by changing the syringes 1la and 1lb in accordance with changes in the rated flow quantity of the continuous liquid feed system 50. Further, the syringes lla and 11b can be easily removed for washing.
The rotary valves 22a and 22b switch the syringe type liquid feed pumps 18a and 18b to each other so as to perform a suction operation or a discharge operation. The pressure sensor 23 and the flowmeter 26 always measure a pressure and a flowgquantity in the pipe 19 tobe transmitted to the controller 31. If the value measured by the pressure sensor 23 and the flowmeter exceeds a predetermined threshold value, the controller 31 determines that the pressure or fiow quantity is abnormal to stop the rotation of the motors 13a and 13b. Thereby, iiquid clogging that mainly occurs in the piping unit 20 can be detected to prevent the continuous liquid feed system 5C from being damaged due to an emergency stop or an abnormal high pressure. Further, the values of the pressure and flow quantity are automatically recorded into the storing unit 31a in the controller 31 to be able to be used as experimental data when using the continuous liquid feed system 50 as an experimental device or used as initial data at the time of manufacturing when using the continucus liquid feed system 50 as a manufacturing device.
Tubes made of fluorine resin excellent in chemical resistance are selected for the pipes 24a, 24b, and 29. Inorder to prevent variations in the feeding amount of liquid due to deformation of the tubes, thick and hard tubes are especially preferable. Tf the liquid to be fed is low-corrosive liquid such as water, stainless-steel pipes may be used.
When signals are transmitted from the controller 31 to the motors 13a and 13b through the signal line S5 and S6 in the liquid feed unit 10, the motors 13a and 13b are rotated. Along with the rotation of the motors 13a and 13k, the ball screws 14a and 14b start to move. Then, the rotational motion of the motors 13a and 13b is converted into the reciprocal motion in the vertical direction of Fig. 1. At this time, the controller 31 controls the rotational motion of the motors 13a and 13b to allow two plungers 12a and 12b to performa liquid feed operation or a suction operation.
As explanations of the slide blocks 15a and 15b attached to the ball screws 14a and 14b in a movable manner, if one slide block 15a is moved upward in accordance with the movement of the ball screws 14a and 14b, the other slide block 15b can be moved downward. Specifically, the slide blocks 15a and 15b can be moved opposite to each other. Accordingly, when cone of the plungers 12a and 12b performs a liquid feed operation, the other of the plungers 12b and 12a can perform a suction operation.
Because plural motors 13a and 13b are provided as described above, the plungers 12a and 12b can be separately contrclled. As a result, the syringe type liquid feed pumps can be operated in such a manner that the liquid feed operation and the suction operation can be performed at different velocities, the suction operation can be completed in a short time, the liquid feed operations can be simultaneously performed, or the syringe type liquid feed pumps 18a and 18b can be operated differently from other syringe type liguid feed pumps.
The following is the reason for using the ball screws 14a and 14b as units to convert the rotational motion of the motors 13a and 13b into the reciprocal motion in the embodiment.
Although there are some mechanisms to convert rotational motion into linear motion, the present invention is most suitable for controlling pumps such as the syringe type liquid feed pumps 18a and 18b used to feed a small amount of liguid because the amount of movement and the velocity can be precisely transmitted.
If such precise accuracy in liquid feeding is not required, a method using a timing belt or crank may be employed.
Operations of the continuous liquid feed system configured in such a manner will be described with reference to Fig. 2 and Figs. 3. An explanation will be made below while an ordinal number “first” is added to each of constitutional elements having reference numerals with “a” in Fig. 1 and an ordinal number “second” is added to each of constitutional elementg having reference numerals with "b”. A system including the first syringe type liquid feed pump 18a is referred to as a first syringe type liguid feed pump system, and a system including the second syringe type liquid feed pump 18b is referred to as a second syringe type liquid feed pump system.
In Fig. 2, upper three pieces are time charts in the first syringe type liquid feed pump system, and lower three pieces are time charts in the second syringe type liquid feed pump system. The horizontal axis represents time t(s), and the vertical axis represents, in order from the above, the flow velocity (mm/s) of liquid discharged from the syringe type liquid feed pumps 18a and 18b, the displacement {stroke} & (mm) of the syringes 1la and 11b, and the positions Ly of the rotary valves 22a and 22b in the first syringe type liguid feed pump system and the second syringe type liguid feed pump system. In this case, the radiuses of the syringes lla and 11b are the same in the first and second syringe type liquid feed pump systems.
Thus, the flow velocity V of liquid in the syringe type liquid feed pumps 18a and 18b is proportional toa flow quantity Q (uL/s) .
An operation of the continuous liquid feed system 50 in each of regions represented by A10 to A28 of Fig. 2 will be described. [Region Al0]
The region Al1C represents an operation of the continuous liquid feed system 50 at the time of start-up. Specifically, the first syringe type liquid feed pump system and the second syringe type liquid feed pump system are in an initial state.
The first rotary valve 22a is on the suction side and is in communication with the container 40. At first, the first syringe lla is in a fully-closed state, namely, an internal content of 0. Thereafter, the plunger 12a is pulled at a predetermined velocity until a time p0 where the stroke becomes maximum, and then the suction from the container 40 is stopped.
At this time, the second syringe type liquid feed pump system is in a resting state. In the embodiment, the second rotary valve 22b is also set on the suction side, and the second syringe 11b ig in a fully-closed state. [Region All]
The region All represents a switching operation of the first rotary valve 22a. Since the suction operation has been completed in the first syringe type liquid feed pump system, it is necessary to switch toa discharge operation. Accordingly, the first rotary valve 22a is switched between the time p0 and a time pl. At this time, a dead volume amount that does not contribute to liquid feeding is formed inside the first rotary valve 22a. Thus, liquid is preliminarily fed by the dead volume amount. The second syringe type liguid feed pump system is still in an initial state. [Region Al2]
The region Al2 represents a region where a predetermined amount of liquid is fed to the continucus liquid feed system 50 by the first syringe type liquid feed pump 18a, and the liquid is fed at a constant flow velocity only between the time pl and a time p2. At this time, the second syringe type liquid feed pump 18b starts to suck solution from the container 40 at a time gf that is later than the time pl. If the second plunger 12b sucks up to the maximum capacity between the time g0 and a time gl, the second rotary valve 22b is operated to be switched from the suction state to the discharge state in the following period between the time gl and a time g2 represented by the region A21.
At this time, a dead volume amount that does not contribute to the discharge occurs as similar to the first rotary valve 22a.
Thus, the second plunger 12b performs the discharge operation so as to start the discharge to the demander when the switching ig completed. [Region Al13 and Region A22]
The regions are characteristic ones in the present invention. The regions are those to suppress pulsation generated when switching the first syringe type liquid feed pump system and the second syringe type liquid feed pump system to each other. Specifically, when the discharge operation in the first syringe type liquid feed pump system comes to an end, the discharge operation of the second syringe type liquid feed pump system is overlapped, so that the discharge operation of the first syringe type liquid feed pump system is gradually shifted to the discharge operation of the second syringe type liquid feed pump system.
After the first plunger 12a starts to be decelerated at the time p2 (=g2=t1), the first syringe type liquid feed pump 18a is allowed tobe ina fully-closed state at a time p3 (=g3=t2).
Solution is discharged from the second syringe type liquid feed pump 180 by the amount corresponding to the decrease in the flow velocity (flow quantity) in the first syringe type liguid feed pump lé&a. [Region A23] ib The region A23 is one where the discharge cperation is completely shifted to the second syringe type liquid feed pump 18b and a predetermined capacity of solution is discharged only with the second syringe type liquid feed pump 18b. This state is continued between a time g3 and a time g4. It is necessary for the first syringe type liquid feed pump 18a to complete the suction operation in this period and to be ready for the discharge operation. Therefore, the rotary valve 22a is switched to the suction side between the time g3 and the time g4 in which the discharge operation is shifted to the second syringe type liquid feed pump 18b. Continuously, solution is started to be sucked from the container 40, and the suction is completed at a time p5. When the suction is completed, the rotary valve 22a ig switched to the discharge side again between the time p5 and a time ps6. [Region Al4 and Region A24]
The regions are those where the discharge operation is shifted from the second syringe type liquid feed pump 18b to the first syringe type liquid feed pump 18a. At the time pé (=g4=t3) when the first syringe type liquid feed pump 18a is ready for the discharge operation, the discharge velocity from the second syringe type liquid feed pump 18b is decreased, and solution is discharged from the first syringe type liquid feed pump 18a by the amount corresponding to the decrease in the flow velocity (flow quantity).
Thereafter, the above-described operations are repeated to prevent pulsation in the discharge flow of the continuous liquid feed system 50 caused by switching the first and second syringe type liquid feed pump systems to each other.
Specifically, the first rotary valve 22a and the first plunger 12a are operated at timings represented by pé to plé of Fig. 2 in the first syringe type liquid feed pump system. On the other hand, the second rotary valve 22b and the second plunger 12b are operated at timings represented by gb to gl5 in the second syringe type liquid feed pump system. In this case, the timing of switching the first syringe type liquid feed pump system is synchronized with that of switching the second syringe type liquid feed pump system between the time t4 and the time TiO.
The operations illustrated in Fig. 2 are thereafter continued and repeated until a necessary capacity of liquid is fed to the demander.
As being apparent from Fig. 2, the moving velocity of each of the plungers 12a and 12b is made faster in the suction operation than that in the discharge operation in the operations of the first and second syringe type liquid feed pumps 18a and 18k. The reason ig that it is necessary to overlap the both discharge operations of the first and second syringe type liquid feed pumps 18a and 18b with each other. In addition, while vacuum suction is employed in the suction, liquid flows under 100kPa in the discharge. Thus, flow resistance and required power can be made smaller in the case of vacuum suction as compared to the discharge operation.
An operational flow of the continuous liquid feed system 50 will be described using flowcharts shown in Figs. 3. InFigs. 3, all operations of the first and second plungers 12a and 12Db in the first and second syringe type liguid feed pumps 18a and 18b are shown using pumps.
When the continuous liquid feed pump system 50 is started, the controller 31 initializes the first and second syringe type liquid feed pump systems (Step S100}. Next, solution is sucked from the container 40 to the inside of the syringe lla with the first syringe type liquid feed pump 18a (Step 5102). The controller 31 determines whether or not the stroke of the first plunger 12a has become maximum or the first plunger 12a has moved to a predetermined position to complete the suction (Step S104).
It should be noted that when a stepping motor is used for the first driving motor 13a, the driving motor 13a determines whether or not to have reached the required number of steps.
If the suction with the first syringe type liquid feed pump 18a has been completed, the first rotary valve 22a is switched from the suction side to the discharge side. Along with this, solution is discharged from the first syringe type liquid feed pump 18a by the dead volume amounts of the first rotary valve 22a and a connection part of the first rotary valve 22a (Step S106). The controller 31 determines whether or not the switching of the first rotary valve 22a has been completed (Step $5108).
If the first rotary valve 22a has been completely switched to the discharge side, the first plunger 12a is pressed down at a constant velocity to discharge the solution in the first syringe lla (Step S110). During the operation of Step 5110, the second syringe type liquid feed pump 18b sucks solution from the container 40 to the inside of the syringe 11b (Step S112).
Then, the controller 31 determines whether or not the stroke of the second plunger 12b has become maximum or the second plunger 12b has moved to a predetermined position to complete the suction (Step $114). It shouldbe noted that when a stepping motor 1s used for the seccend driving motor 13b, the driving motor 13b determines whether or not to have reached the reguired number of gteps.
If the suction with the second syringe type liquid feed pump 18b has been completed, the second rotary valve 22b is switched from the suction side to the discharge side. Along with this, sclution is discharged from the second syringe type liquid feed pump 18b by the dead volume amounts of the second rotary valve 22b and a connection part of the second rotary valve 22k (Step Sl1lle).
The controller 31 determines whether or not the switching of the second rotary valve 22b has been completed (Step S118).
If the second rotary valve 22b has been completely switched to the discharge side, the controller 31 allows the first and second syringe type liguid feed pumps 18a and 18b to be synchronized with each other. Specifically, the first plunger 12a of the first gyringe type liquid feed pump 18a is decelerated.
Then, the plunger 12b of the second syringe type liquid feed pump 18b is accelerated at the same timing by the amount corresponding to the deceleration (Step S120). Accordingly, the amount of solution to be discharged from the pipe 19 can be made constant.
The controller 31 determines whether or not the velocity of the plunger 12a of the first syringe type liquid feed pump
18a has become 0 and the velocity of the plunger 12b of the second syringe type liquid feed pump 18b has become maximum or a predetermined value (Step S122). If the velocity cf the plunger 12b of the second gyringe type liquid feed pump 18b has become the predetermined value, the second syringe type liquid feed pump 18b keeps the velocity (Step S124).
On the other hand, the first syringe type liquid feed pump 18a executes the following steps in the period the second gyringe type liquid feed pump 18b discharges the solution at a constant velocity. Specifically, the first rotary valve 22a is switched from the discharge side to the suction side (Step 8126). Then, it is determined whether or not the first rotary valve 22a has been switched (Step S128). Then, solution is sucked from the container 40 (Step $130). The controller 31 determines whether or not the first plunger 12a has sucked up to a predetermined capacity or the maximum stroke (Step S132).
Thereafter, the first rotary valve 22a is switched from the suction side to the discharge side (Step $134). The controller determines whether or not the first rotary valve 22a has been completely switched (Step S136).
If the first rotary valve 22a has been completely switched to the discharge side, the controller 31 allows the first and second syringe type liquid feed pumps 18a and 18b to be synchronized with each other. Specifically, the second plunger 12b of the second syringe type liquid feed pump 18b is decelerated. Then, the plunger 12a of the first syringe type liquid feed pump 18a is accelerated at the same timing by the amount corresponding to the deceleration (Step S138).
The controller 31 determines whether or not the flow velocity of the second syringe type liguid feed pump 18b has become 0 and the flow velocity of the first syringe type liquid feed pump 18a has reached the maximum value or a predetermined value (Step 8140}. Then, the first syringe type liquid feed pump 18a keeps the flow velocity (Step S142). In the period the first syringe type liquid feed pump 18a discharges the solution at a constant velocity in Step 5142, the second syringe type liquid feed pump 18b performs the following operations.
Specifically, the second rotary valve 22b is switched from the discharge side to the suction side (Step S144). Then, the controller 31 determines whether or not the second rotary valve 22b has been completely switched (Step $146). Then, solution is sucked from the container 40 (Step S148). The controller 31 determines whether or not the second plunger 12b has sucked up to a predetermined capacity ox the maximum stroke (Step $150). Thereafter, the second rotary valve 22b is switched from the suction side to the discharge side (Step S152).
The controller 31 determines whether or not the second rotary valve 22b has been completely switched (Step 5154).
If the second rotary valve 22b has been completely switched to the discharge side, the controller 31 allows the first and second syringe type liguid feed pumps 18a and 18b to be synchronized with each other. Specifically, the first plunger 12a of the first syringe type liquid feed pump 18a is decelerated. Then, the plunger i2b of the second syringe type liquid feed pump 18b is accelerated at the same timing by the amount corregponding to the deceleration (Step S156). Step 5158 to Step 8172 are the same as the operations from Step S120 to Step S136.
Thereafter, for example, Step 8124 to Step 8150, namely, the operations between the time t2 and the time t5 are repeated until the amount of liguid demanded by the demandexr is fed. It should be noted in the flowchart that the controller 31 controls the operations of the first and second syringe type liquid feed pumps 18a and 18b and the switching of the first and second rotary valves 22a and 22b in a feedback manner. However, control units for the first and second motors 13a and 13b as stepping motors may control the respective devices in a feedforward manner.
According to the embodiment, the liquid feed (acceleration) operation of the second plunger 12b is started at the start timing of the deceleration operation immediately before the completion of the liquid feed operation of the first plunger 12a, or the opposite operation is performed. Thus, the liquid feed operations of the first and second plungers 12a and 12b are overlapped with each other. Accordingly, the deceleration and acceleration velocities of the two plungers
12a and 12b are allowed to match each other, so that the set liquid feed velocity can be kept and continuous liquid feeding can be stably performed without pulsation.
Further, as the timing of switching the first and second plungers 12a and 12b to each other, the timing of starting the deceleration operation by one plunger 12a (or 12b} can be obtained only by controlling the rotation of the first and second motors 12a and 13b and by counting the pulse value of the controller 31, and the liquid feed (acceleration) operation of the other plunger 12b (or 12a) is started in synchronization.
Further, if a function of determining the operation timing of each device by automatic self-learning of an apparatus is provided, optimum liguid feeding can be performed without pulsation. Specifically, as an automatic self-learning function, the switching timing of the plunger, namely, the activation timing and acceleration/deceleration time of the motor are sequentially and automatically operated in plural patterns, and the timing at which the measurement value of the pressure sensor or the flowmeter is most stabilized may be recorded into the controller to be reflected on the liguid feed operation.
Claims (10)
1. A continuous liguid feed system that sucks and pressurizes liguid accommodated in a container to be discharged to a demander, the gystem comprising: plural pumpse which are in communication with the container; valves each of which is provided for each pump and which are arranged between the pumps and the container; motors each of which is provided for each pump to drive the same; and a controller which controls the motors and the valves, wherein when discharging a predetermined flow quantity to the demander with one pump, the controller allows the other pump to perform a suction operation or stops the other pump, decreases the flow quantity discharged by the one pump in a predetermined period from the time the one pump starts to discharge and in a predetermined period immediately before completion of the discharge, and controls the plural pumps and the valves so as to allow the other pump to discharge only the decreased flow quantity.
2. The continuous liguid feed system according to claiml, wherein the valves are rotary valves, the plural pumps are plural syringe type liquid feed pumps, and the controller controls continuous liquid feeding by switching the discharge and suction operations of the plural syringe type liquid feed pumps to each other.
3. The continuous liguid feed system according to claim 1, wherein the plural pumps are two syringe type liquid feed pumps, and the controller allows the two syringe type liquid feed pumps to alternately repeat an independent discharge operation, and controls the discharge operations of the both syringe type liguid feed pumps to be overlapped with each other before and after the independent discharge operation of each syringe type liguid feed pump.
4. The continuous liquid feed system according to claim 1, wherein a flowmeter for detecting the flow quantity of liguid discharged from the pumps and a pressure gauge for detecting the pressure of the liquid are provided between discharge parts of the pumps and the demander, a storing unit for storing a control data table of combination patterns between the activation timings and the acceleration/deceleration time of the motors that drive the pumps is provided at the controlier, and the controller drives the pumps using the control data stored in the storing unit under the conditions that the measurement values of the pressure gauge and the flowmeter are most stabilized.
5. The continuous liguid feed system according to claim 2, wherein the plural pumps are two syringe type liquid feed pumps, and the controller allows the two syringe type liquid feed pumps to alternately repeat an independent discharge operation, and controls the discharge operations of the both syringe type liquid feed pumps to be overlapped with each other before and after the independent discharge operation of each syringe type liquid feed pump.
6. The continuous liquid feed system according to claim 2, wherein a flowmeter for detecting the flow quantity of liquid discharged from the pumps and a pressure gauge for detecting the pressure of the liquid are provided between discharge parts of the pumps and the demander, a storing unit for storing a control data table of combination patterns between the activation timings and the acceleration/deceleration time of the motors that drive the pumps is provided at the controller, and the controller drives the pumps using the control data stored in the storing unit under the conditions that the measurement values of the pressure gauge and the flowmeter are most stabilized.
7. The continuous liquid feed system according to claim 3, wherein a flowmeter for detecting the flow guantity of liquid discharged from the pumps and a pressure gauge for detecting the pressure of the liquid are provided between discharge parts of the pumps and the demander, a storing unit for storing a control data table of combination patterns between the activation timings and the acceleration/deceleration time of the motors that drive the pumps is provided at the controller, the controller drives the pumps using the control data stored in the storing unit under the conditions that the measurement values of the pressure gauge and the flowmeter are most stabilized.
8. The continuous liquid feed system according to claim 3, wherein a flowmeter for detecting the flow guantity of liguid discharged from the pumps and a pressure gauge for detecting the presgure of the liquid are provided between discharge parts of the pumps and the demander, a storing unit for storing a control data table of combination patterns between the activation timings and the acceleration/deceleration time of the motors that drive the pumps is provided at the controller, the controller drives the pumps using the control data stored in the storing unit under the conditions that the measurement values of the pressure gauge and the flowmeter are most stabilized.
9. A control method of a continuous liquid feed system that sucks and pressurizes liquid accommodated in a container to be discharged to a demander using: two syringe type liquid feed pumps with the same capacity that are in communication with the container; rotary valves each of which is provided for each of the two syringe type liquid feed pumps and which are arranged between the syringe type liquid feed pumps and the container; motors each of which is provided for cach syringe type liquid feed pump to drive the same; and a controller which controls the motors and the rotary valves: wherein the two syringe type liquid feed pumps are allowed to alternately perform a suction operation and a discharge operation; when one syringe type liguid feed pump independently performs the suction operation, the other syringe type liquid feed pump is allowed to perform the suction operation, and the other syringe type liquid feed pump is allowed to perform the discharge operation only in a predetermined period immediately before starting the independent operation of one syringe type liquid feed pump and only in a predetermined period before completion of the independent operation; and when the both syringe type liquid feed pumps perform the discharge operation, the one syringe type liguid feed pump is decelerated, and the other syringe type liquid feed pump is accelerated by the amount corresponding to the deceleration of the one syringe type liquid feed pump.
10. The contrel method of a continuous liquid feed system according to claim 9, wherein when the one syringe type liguid feed pump performs the independent discharge operation, the rotary valve connected to the other syringe type liquid feed pump is switched from the discharge side to the suction side, solution is sucked from the container with the cther syringe type liquid feed pump, and the rotary valve connected to the other syringe type liquid feed pump is switched from the suction side te the discharge side.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011148251A JP2013015072A (en) | 2011-07-04 | 2011-07-04 | Continuous liquid feed system and control method for the same |
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| Publication Number | Publication Date |
|---|---|
| SG186589A1 true SG186589A1 (en) | 2013-01-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SG2012049490A SG186589A1 (en) | 2011-07-04 | 2012-07-04 | Continuous liquid feed system and control method thereof |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2013015072A (en) |
| CN (1) | CN102865205A (en) |
| DE (1) | DE102012211192A1 (en) |
| FR (1) | FR2977643A1 (en) |
| SG (1) | SG186589A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103821706A (en) * | 2014-02-26 | 2014-05-28 | 苏州市玄天环保科技有限公司 | Method for controlling flow of peristaltic pump accurately by means of gear motor |
| CN104033348B (en) * | 2014-06-09 | 2016-09-21 | 四川大学 | The continuous topping-up pump of digital quantitative |
| JP2016048106A (en) * | 2014-08-28 | 2016-04-07 | 株式会社ナガセインテグレックス | Static pressure bearing device |
| CN104888305B (en) * | 2015-05-27 | 2018-10-23 | 深圳市仕浦电气有限公司 | Transfusion system and infusion method |
| CN106438322B (en) * | 2016-10-10 | 2017-09-29 | 长春市科意试验仪器有限公司 | A kind of double core flooding pumping discharge opeing control systems tested based on rock indoor |
| CN107917064A (en) * | 2016-10-10 | 2018-04-17 | 天津有序环境科技发展有限公司 | More uniformly ammoniate method for controlling pump |
| CN107917065B (en) * | 2016-10-10 | 2019-09-27 | 天津有序环境科技发展有限公司 | The ammonification of simplified transformation existing system pumps equal control method |
| CN107693076A (en) * | 2017-10-31 | 2018-02-16 | 无锡贝恩外科器械有限公司 | A kind of controllable digestive tract stapler of dose |
| DE102020107910A1 (en) * | 2019-04-04 | 2020-10-08 | Dionex Softron Gmbh | Liquid chromatography method, system and use for sampling |
| WO2020248141A1 (en) * | 2019-06-11 | 2020-12-17 | 海安县石油科研仪器有限公司 | Circulating constant-flow constant-pressure metering pump device |
| WO2021087654A1 (en) * | 2019-11-04 | 2021-05-14 | 深圳英瑞生物科技有限公司 | Infusion system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3541467B2 (en) * | 1994-12-28 | 2004-07-14 | 東レ株式会社 | Single wafer coating apparatus and method |
| JP3903827B2 (en) * | 2002-04-02 | 2007-04-11 | 株式会社島津製作所 | In-line double syringe feed pump and liquid chromatograph |
| JP2004150402A (en) * | 2002-11-01 | 2004-05-27 | Hitachi High-Technologies Corp | Pump for liquid chromatography |
| JP2005147756A (en) * | 2003-11-12 | 2005-06-09 | Shimadzu Corp | Liquid feed pump device |
| JP2006126089A (en) * | 2004-10-29 | 2006-05-18 | Hitachi High-Technologies Corp | Liquid feed pump device |
| JP4841150B2 (en) * | 2005-03-23 | 2011-12-21 | リコーエレメックス株式会社 | Flux application device |
| CN101721839B (en) * | 2009-12-18 | 2012-06-27 | 北京创新通恒科技有限公司 | Infusion method of liquid chromatogram and dual-drive high pressure pump |
-
2011
- 2011-07-04 JP JP2011148251A patent/JP2013015072A/en not_active Withdrawn
-
2012
- 2012-06-26 CN CN2012102144588A patent/CN102865205A/en active Pending
- 2012-06-27 FR FR1256102A patent/FR2977643A1/en not_active Withdrawn
- 2012-06-28 DE DE201210211192 patent/DE102012211192A1/en not_active Ceased
- 2012-07-04 SG SG2012049490A patent/SG186589A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| CN102865205A (en) | 2013-01-09 |
| DE102012211192A1 (en) | 2013-01-10 |
| JP2013015072A (en) | 2013-01-24 |
| FR2977643A1 (en) | 2013-01-11 |
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