US3587670A - Sampler and pumping system - Google Patents

Abstract

A SYSTEM TO TRANSFER FLUID FROM A SOURCE TO ONE OR MORE CONTAINERS WITHOUT THE FLUID COMING INTO CONTACT WITH ANY OF THE MOVABLE MEMBERS PUMPING IT SUCH AS VALVES, PISTONS AND THE LIKE. IT INCLUDES A CLOSED HOLLOW CHAMBER, A VACUUM PUMP TO EVACUATE THE CHAMBER, A FLOAT ACTUATED SWITCH IN THE CHAMBER TO TURN THE PUMP ON AND OFF DEPENDING ON THE LEVEL OF THE FLUID IN THE CHAMBER AND ONE OR MORE CONTAINERS TO RECEIVE AND STORAGE THE FLUID. A CONNECTING TUBE EXTENDS FROM

THE BOTTOM OF THE CHAMBER TO THE CONTAINERS AND ANOTHER TUBE EXTENDS FROM THE CHAMBER TO THE FLUID SOURCE.

Description

United States Patent [72] Inventor Harrison D. Brailslord 670 Milton Road, Rye, N.Y. 10580 [21] Appl. No. 689,130 [22] Filed Dec. 8, 1967 [45] Patented June 28, 1971 [54] SAMPLER AND PUMPING SYSTEM 5 Claims, 5 Drawing Figs.

[52] U.S.Cl 141/35, 73/421,141/61, 200/84 [51] Int. Cl G01n 1/14 [50] Field of Search 73/421 (B); 103/236; 137/255, 257, 412, 432, 571; 141/35, 36, 60, 61; 200/843, 84 (Curs y); 222/67, 69; 335/153 (Cursory) [56] References Cited UNITED STATES PATENTS 832,764 10/1906 Wood et al. 103/236 1,518,890 12/1924 Aikman 103/236 1,967,800 7/1934 Woodbridge l37/57lX 2,995,037 8/1961 Parker et al. 73/42lB 3,408,053 10/1968 Vantroba ZOO/84X FOREIGN PATENTS 720,161 12/1954 Great Britain 73/421 B Primary Examiner- Laverne D. Geiger Assistant Examiner- Edward J. Earls Att0rney-- Donald P. Gillette ABSTRACT: A system to transfer fluid from a source to one or more containers without the fluid coming into contact with any of the movable members pumping it such as valves, pistons and the like. It includes a closed hollow chamber, a vacuum pump to evacuate the chamber, a float actuated switch in the chamber to turn the pump on and off depending on the level of the fluid in the chamber and one or more containers to receive and store the fluid. A connecting tube extends from the bottom of the chamber to the containers and another tube extends from the chamber to the fluid source.

PATENlfflJunzslsn I 3,587,670

' SHEET 'IDF 2 INVENTOR. HARRLSON D BRAILSIORD SAMPLER AND PUMPING SYSTEM This invention relates to a system and apparatus for pumping fluid into one or more containers without requiringtthe fluid to pass through valves or any moving part of the pumping mechanism. In particular, the invention relates to a pumping system which is electrically operated and is internally controlled to pump fluid into a sample container or containers at a predetermined, relatively slow rate or intermittently or both.

In testing samples of fluid such as effluent water from streams, industrial outfalls or sewers in order to analyze the contents of the fluid for pollutionmeasurements and the like, it is desirable to avoid having the fluid traverse restricted passages or ports that must be substantially completely closed at certain times to the ,flow. Pistons and valves in the usual pumping systems frequently get clogged by solid matter suspended in the fluid under investigation and thereupon either cease to operate entirely or operate improperly or inefficiently.

In accordance with the present invention, a hollow chamber is provided with means connecting it to the fluid supply to: be analyzed and with a vacuum pump to reduce the air pressure in the chamber so as to suck the fluid into the chamber. A switch connected to control the pump is located within'thc chamber to turn the pump off when the chamber has been filled to a certain level. y

In one embodiment, the chamber has an orifice of small size through which air can leak into the chamber at a slower rate than the pump can withdraw it. In another embodiment the chamber has an air valve that is normally closed but with means to open it so that air can enter the chamber to relieve the partial vacuum when the pump is not operating. Thus when the pump stops and air fills the chamber, the fluid will-.be drawn or forced into the container by the external atmospheric pressure. f

In order to control the pump, means such as a magnetically operated switch and a float containing a permanent magnet are located within the chamber. The switch is connected so. as to turn off the pump motor when the chamber has become filled to a certain level determined by the position of the switch and the position of the magnet in the float, and the pump will operate until the float is raised by the incoming fluid to this level. Thereupon the pump motor is turned off and the fluid level subsides due to the inward flow of air through the orifice or valve. The subsiding fluid flows into the'container to be held there for future analysis.

In order to permit the fluid to be transferred from the chamber to the container during each cycle of operation, time delay means are provided to maintain the pump in its turned off condition for a given length of time.

The invention will be described in greater detail in connection with the drawings in which:

FIG. 1 shows, diagrammatically, the mechanical components of the system;

FIG. 1a shows a modification of part of the system .in FIG. 1;

FIG. 2 is a schematic electrical circuit diagram of the operating circuit for the apparatus shown in FIG. 1;

FIG. 3a shows a transfer chamber for filling the first container and subsequently transferring additional effluent to another container; and

FIG. 3b shows a series of containers with transfer chambers for operation in conjunction with the system of FIG. 1.

The apparatus in FIG. 1 comprises a sample container 11 which may be a -gallon jug or any container of suitable size for the purpose. This container is completely closed and is connected to a hollow chamber 12 by means of a pipe or tubing 13 through which the fluid to be analyzed is transmitted from the chamber 12 to the container 11. Theforceto transfer the-fluid is provided by an electrically driven vacuum pump 14 connected to the chamber 12 by a hollow tube 15.

For the purpose to be described in greater detail hereinafter, the chamber 12 is provided with an orifice 16 of limited cross-sectional size such that the pump 14 can withdraw air. from the chamber 12 faster than the orifice can admit new air.

The chamber 12 has an inlet tube 17 that extends through the wall of the chamber and terminates at a distance somewhat above from the bottom of the chamber. Within the chamber is afloat, 18 which may be toroidal in shape and have a hollowed out central portion 19 and an inner hollow channel 21 that fits loosely over the upper end of the pipe 17 within the chamber to guide the movement of the float. The float 18 also contains a magnet 22 which, in the present embodiment, is located adjacent the central opening 19.

A hollow tube 23 extends into the chamber 12 from-the upper surface thereof in a direction parallel to the end of the pipe 17. As may be seen, the lower end of the hollow tube 23 extends into the upper end of the central opening 19 to help guide the float and to make sure that the magnet 22 moves along a path that will bring it close to a switch 24 within the hollow tube. This switch is hermetically walled off from the main part of the chamber 12 by the tube so as not to come in contact with the fluid. This switch is connected by wires 26 to a control circuit 27 that controls the operation of the electric motor of the pump 14. The circuit 27 is energized by a battery 28 upon closing a switch 29 andis connected to a pump motor by wires 31.

As may be seen, the lower end of the pipe 17 extends into a body of fluid 32 which may be a flowing stream of water or any other fluid to be analyzed and capable of buoyantly supporting the float 18 in the chamber 12.

The operation of the apparatus in FIG. 1 begins initially with the float 18 resting on the bottom of the chamber 12. In this position, the magnet 22 is well awayfrom the switch 24 and therefore, this switch is open. The circuit connections within the circuit control 27 are such that the motor 14 is capable of running when the switch 24 is open, as it is initially.

As the pump 14 runs, it withdraws air from the chamber 12 by way of the connecting .hollow tube 15. At the same time air is withdrawn from the container 11 by way of the conduit 13 so that both the chamber 12 and the container 11 are partially evacuated. The process of evacuation or removal of air from the chamber and the sample container is somewhat slowed down because of the simultaneous admission of air through the orifice 16, but the size of this orifice is such that the pump 14 can remove air faster than the orifice can admit it thereby producing a net reduction in the air pressure within the container l1 and the chamber 12. As a result of this reduced air pressure, fluid is drawn up from the source 32 through the pipe 17 into the chamber 12. As the fluid flows into the chamber 12, it forms a buoyant support for the float 18 which then rises with the rising fluid. Because of the interlinking of the hollow tube 23 and the pipe 17 with the float, the latter is constrained to rise vertically until the magnet 22 reaches a position opposite switch 24. When the field of the magnet links sufficiently with the magnetic elements in the switch, the latter closes to actuate the circuit 27. While the operation of the circuit 27 will be described in greater detail hereinafter, it is sufficient at this point to say that the closing of the switch 24 halts the flow of electric current through the lines 31 and causes the motor of the pump 14 to stop. As a result, no further air is withdrawn from the chamber 12 but instead, air flowing into the chamber by way of the orifice 16 permits the fluid that has accumulated in the chamber to flow through the conduit 13 into the container 11 and at the same time, the fluid in the pipe 17 that has not yet reached the upper end returns to the fluid source 32.'If the pump is kept inoperative long enough, all of the fluid will be purged from the pipe 17 and all of the fluid in the chamber will be forced through the conduit into the container 11 and the float 18 will return to its lowermost position at which it rests on the floor of the chamber 12. In actual practice, the pump need not be held in its inoperative condition for this long but preferably, it should be maintained inoperative long enough to permit a significant transfer of fluid into the sample container 11 and to permit substantial purging of the pipe 17. In this way, a minimum of stagnant material can collect on the walls of the conduit 13 and the pipe 17 to restrict subsequent fluid flow.

The control circuit shown in FIG. 2 comprises the switch 29 connected in series with the battery 28 and a capacitor 33. The motor ofthe pump 14 is connected by the electric lines 31 through the normally closed contacts 34 and 36 of a relay 37 to the negative terminal of the battery 28. The switch 29 is also connected in series with the lines 31. The relay 37 is controlled by a time delay circuit which comprises the capacitor 33 and a resistor 38 the respective values of which determine the repetition rate of the operating cycle. The capacitor 33 is connected through a current limiting resistor 39 to the base of a transistor 41, such as a FET, the emitter-collector circuit of which is connected in series with the coil of the relay 37, the switch 29, and the battery 28.

The operation of the circuit in FIG. 2 begins with the magnet 22 some distance below the switch 24 so that the contacts in the latter are open. Under this circumstance, and if the switch 29 is closed, current will flow from the battery 28 through the switch 29 and the contacts 34 and 36 to operate the motor of the pump 14. As explained above, this results in bringing fluid into the chamber 12 (FIG. 1) which causes the magnet 22 to move to a position at which its field closes the switch 24. Initially the transistor 41 is nonconductive so that no current flows through the coil of the relay 37 but when the switch 24 is closed, the transistor 41 is biased to its conductive state. This causes current to flow through the coil of the relay 37 through the battery causing the contact 36, which is located on the movable armature of the relay, to become disengaged from the fixed contact 34 to engage the normally open fixed contact 42. Opening the circuit at the contacts 34 and 36 interrupts the flow of current to the motor of the pump 14 and turns the pump off.

When the pump 14 is not operating, air admitted to the chamber 12 through the orifice (FIG. 1) permits the fluid in the chamber to be displaced and allows the float 18 with the magnet 22 to descend. In order not to have the relay 37 become disengaged immediately when the magnet moves just far enough away from the switch 24 to permit the latter to open, an electronic time delay is provided to maintain the relay closed even after the switch has opened.

The connection between the contacts 36 and 42 places the resistor 38 directly in parallel with the capacitor to discharge the latter. As the voltage across the capacitor decreases, a value is eventually reached at which the transistor 41 becomes nonconductive, at which point the relay drops out and the cycle is repeated.

In order to control the repetition rate of the operating cycle, the resistor 38 may be made variable, as shown, to cause the transistor 41 to remain conductive for longer or shorter intervals depending on the setting of the resistor. In addition, the repetition rate may be made dependent on the level of the fluid in the source 32 (FIG. 1) by using a liquid measuring resistor of the type shown and described in my copending application, Ser. No. 445,968, filed Apr. 6, I967, now US. Pat. No. 3,377,537.

The system as described and shown schematically in FIG. 1 may be used when the resulting analysis is confined to a determination of the total percentage of foreign matter present in the effluent as averaged over an extended period such as one or more days. In this case the sample can be composited in a single container. Under some conditions, however, it is desirable to segregate portions of the total sample with respect to specific time periods. For example, in an industrial outfall, where the effluent may be discharged at irregular intervals, or where the nature of the effluent changes materially at different times during the day or during the work shift, it is necessary to take samples at specific intervals and keep them separated in individual containers. For this purpose FIG. 3a shows a closed transfer chamber 43 which may be cylindrical in shape and which has an inlet tube44, an exit tube 45, and a drain tube 46. The transfer chamber is connected by the inlet tube 44 to the bottom of the vacuum chamber 12, by the drain tube 46 to the container 11 of FIG. 1, and by the exit tube 45 to an overflow receptacle which may be another sample container like the container 11. Any desired number of containers may be thus connected in series as indicated in FIG. 3b which shows four sample containers 11a- 1 1d.

The operation of the system for filling a multiplicity of sample containers is described with reference to FIGS. 1 and 3b as follows:

When the vacuum pump 14 runs, it draws air out of the chamber 12 and, through the interconnecting tubes, from all of the sample-receiving containers Ila-11d. When the pump stops, air entering the orifice 16 allows the charge of fluid that has been drawn into the chamber 12 to flow out through the tube 44a into the first transfer 43a. As the fluid enters the chamber 43a, it falls to the bottom and immediately starts to flow through the drain tube 46a into the container 110. Depending upon the relative sizes of the tubes 44a and 46a, the fluid may or may not flow out of the transfer chamber 43a as fast as it flows in. However, the capacity of the chamber 43a is preferably great enough and the exit tube 45a high enough above the bottom of the chamber 43a so that this chamber will be capable of retaining an entire charge of fluid corresponding to one filling of the chamber 12 without having this fluid pass out through the exit tube 45a. The larger the drain tube 46 a relative to the inlet 44a, the smaller the capacity of the chamber 43a may be.

The size of the container lla'will determine how many charges of fluid from the chamber 12 will be required to fill it. Once filled, succeeding charges of fluid will pass out through the exit tube 45a, which becomes the entrance tube 44b for the second transfer chamber 43b, and will begin to fill the second sample-receiving chamber 11b. If the pump 14 operates at a constant rate, and if the container 11b is the same size as the container 11a, each one will be filled in the same length of time. However, the containers 11a and 11b can be of different sizes or the circuit that controls the pump can force the latter to operate faster at one time than another so that the time required to fill the containers 11a and 11b need not be the same.

The drain tube 46a between the chamber 430 and the container 11a serves as a barrier to prevent fluid already in the container from mixing to any great degree with the fluid that later passes through the chamber 43a to the next container 11b. Of course, there will be some mixing, but the smaller the size of the tube 46a the less mixing there will be. It should be noted that in many instances, as for example when the effluent is the water in the river below an industrial plant, there may not be any sudden change in the constituents of the effluent, and some mixing of the fluid in the first container 11a with that intended for the container 11b or the other containers 11c and 11d will be of little significance. On the other hand, if there must be no mixing, a valve must be placed in each drain tube 46 to seal off the container to which it is connected.

The cycle of operation includes pumping fluid into the chamber 12, permitting the fluid to flow out of this chamber, waiting for the time delay circuit in FIG. 2 to time out, and then starting the pump to begin the next cycle. If a small orifice l6 limits too greatly the rate at which the fluid leaves the chamber 12 and thereby makes the total time for a cycle too long, steps can be taken to adjust the orifice. However, if the size of the orifice remains constant throughout the cycle, the size cannot be too large or it will prevent the pump 14 from evacuating the chamber 12 quickly, if at all.

As an alternative, a larger orifice 116 may be closed by a valve 47 as shown in FIG. 1a. The valve is a solenoid valve in the embodiment shown, but other types could be used instead. Opening and closing of the valve may be controlled by the circuit in FIG. 2 so that the valve will open when the float 18 closes the switch 24 and closes when the motor of the pump restarts. This permits the orifice 116 to be much larger than a fixed orifice and at the same time makes the pumping more efficient because the pump does not have totremove air entering the chamber 12 via the orifice at thesame time that it is removingair already in the chamber.

lclaim:

l. A pumping system comprising: a main hollow chamber; a pump connected to said chamber to withdraw air therefrom: ope'n connecting means to connect said chamber to a supply of fluid; switching means connected to said pump; a float supportable on said fluid in said chamber to actuate said switching means: means to guide said float toward said switching means as said fluids enter said chamber to turn off said pump when a predetermined quantity of fluid has been drawn into said chamber; a fluid transfer chamber directly connected to said main chamber to have air withdrawn from said transfer chamber when said pump operates, whereby said transfer chamber will receive fluid from said main chamber after said pump stops; a first container directly connected to said transfer chamber to receive fluid therefrom; a second fluid container; and open tube means connecting said transfer chamber to said second container to dispense fluid automati-' cally from said transfer chamber to said second container when said first container is full.

2. The pumping system of claim 1 in which said transfer chamber is located on top of said first fluid container.

3. The pumping system of claim 1 in which said transfer chamber has a bottom with an aperture of predetermined size communicating with said first fluid container, and said tube means is connected to said transfer chamber at a distance above said bottom, the volumetric capacity of the portion of said transfer chamber between said tube means and said bottom being substantially equal to the volume of said fluid transferred from said hollow chamber to said transfer chamber in one cycle.

4. The pumping system of claim 1 comprising, in addition: a plurality of additional containers to receive fluid; a corresponding plurality of transfer chambers; open tube means connecting each of said additional transfer chambers directly to one of said additional containers, said tube means connecting said second container to said first-named transfer chamber comprising open tubes connecting said additional transfer chambers in series between said first-named transfer chamber and said second container whereby the fluid will be transferred from each of said transfer chambers to the transfer chamber next beyond it as each of said containers becomes filled.

5. The pumping system of claim 4 in which said fluid containers are of different volumetric capacities.

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