US 3154021 A
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United States Patent 3,154,021 PUMPHNG APPARATUS Jesse T. Vick, In, Lake Jackson, Tex., assignor to The Dow Chemical Company, Midland, MiciL, a corporation of Delaware Filed Mar. 14, 1962, Ser. No. 179,587 7 Claims. (Cl. 103- 148) This invention relates to pumps and particularly to metering pumps for delivering small, precise quantities of fluid on demand.
Metering pumps for delivering small quantities, such as a few cubic centimeters per hour, of more or less corrosive chemicals for use in automatic titration equipment and for other uses are in use commercially. However, many such pumps, when considered on the basis of long time usage, suffer from leakage of packing glands, seals, or malfunction of valves. Other such pumps are expensive to make or to repair.
Accordingly, a principal object of this invention is to provide an improved metering pump.
Another object of this invention is to provide an improved metering pump which is simple to construct and to repair.
A further object of this invention is to provide an improved more reliable metering pump.
Yet another object of this invention is to provide an improved metering pump mechanism having reliable valves which close completely even in the presence of small amounts of particulated materials.
The invention, as well as additional objects and advantages thereof, will best be understood when the fol lowing detailed description is read in connection with the accompanying drawings, in which:
FIG. 1 is a schematic view of metering pump apparatus in accordance with this invention;
FIG. 2 is a side elevational view, in longitudinal section, of the pump mechanism during the fluid intake cycle of operation;
FIG. 3 is a sectional view taken along the line 33 of FIG. 2; and
FIG. 4 is a fragmentary sectional view showing the pump mechanism during the fluid discharge cycle of operation.
Referring to the drawing, and particularly to FIG. 1, there is shown pumping apparatus, indicated generally by the numeral 10. The pumping apparatus comprises an input body section 12, a pumping body section 14, and a driving body section 16. The input section 12 is coupled through a conduit 18 to a reservoir (or other source) 20 of fluid which is to be pumped. An output conduit 22 is coupled to the output section 16 to be coupled to utilization means (not shown) such as automatic titration apparatus, for example.
Compressed air from a suitable source (not shown) is coupled through conduits 24, 26, 28 to sections 12, 14 and 16, respectively. Compressed air is coupled to the output section 16 through a pressure regulator 30 and to the sections 12, 14 through pressure regulators 32, 34 and solenoid valves 36, 38, respectively. The manner of coupling of the conduits 24, 26, 28 to their respective sections will be described in detail later. The valves 36, 38 are actuated electrically by means of leads 40, 42, 44, the lead 40 being coupled to an energization source, not shown, and the leads 42, 44 being coupled to the same energization source through the timer switch 46 and lead 48. Cycling cams 50, 52 are illustrated schematically in connection with the timing control device 46 for operating the valves 36, 38,
Each of the air conduits 24, 26, 28 has a pressure gauge 54, 56, 58 coupled thereto just down stream from the respective regulators 34, 32, 30. Pressure gauges 56,
3,154,021 Patented Oct. 27, 1964 "ice 58 each are coupled to their conduit between the solenoid valves 36, 38 and the regulators 32, 34, respectively.
Referring to FIGS. 2 and 3, as well as to FIG. 1, the pumping apparatus 10 comprises sections 12, 14 and 16 each of which are of block like form, as cubes, for examples. The cubes are of equal size and each have a bore 60, 62, 64, respectively, extending from one side to an opposite side, the bores in each section or block 12, 14 or 16 being equal in diameter and aligning with one another when the sections are operatively assembled together. The bores 66, 62 or 64 in each section each have a slight counterbore at each end (66, 68 in section 12, 66a, 68a in section 14 and 66b, 68b in section 16).
The sections 12, 14, 16 are held together by means of rods 70 which extend between end plates 72, 74.
A hose 76 having resilient walls, such as a rubber hose, extends in close fitting relationship through the wall surface of the aligned bores 60, 62, 64 in the assembled sections 12, 14, 16. The hose 76 has a number of close fitting hollow rigid sleeves 78, 80, 82, 84 disposed within it along its length, one of the sleeves 78, 80, 82 or 84 being disposed in the hose so as to span each junction between two sections 12, 14 or 16 or between a section and an end plate 72, 12 or 16, 74, for example. The outer diameter of each sleeve 78, 80, 82 or 84 is approximately equal to the inner diameter of the hose 76.
As the pumping device 10 is assembled O ring sealing elements 86, 38, 96, 92 are disposed in the counter bores (66, a, b and 68, a, b) which face each other between the adjoining sections 12, 14, 16 and between the end plates 72, 74 and the end surfaces of the adjoining sections.
The effect of the O ring elements, which in each case fit closely around the tube 76 and have a thickness more than twice the depth of any of the counterbores (66, a, b or 68, a, b), is to provide a fluid tight seal between the outer diameter of the tube 76 and the inner Wall of each bore 60, 62 or 64 at each end of the bores when the device is operatively assembled.
A control bore 94, 96, 98 extends from one exposed surface of each section 12, 14 or 16 to the bore 60, 62, or 64, respectively, of that section. The conduits 24, 26, 28 are coupled to the control bores 94, 96, 98, respectively, as by threaded connectors, for example.
The part of the tube 76 which extends outwardly from the end plate 72 is coupled to the conduit 18 and the end of the tube 76 which extends from the end plate 74 is coupled to a suitable utilization means (not shown) such as automatic titration apparatus, for example.
In operation, air is applied through the regulator 30, line 28 and bore 98 at a pressure suflicient to collapse the tube 76 (as at 104) against the back pressure of fiuid entering the device through the tube, the collapsed part of the tube acting as a valve.
Air is then applied through the regulator 34, solenoid valve 38, conduit 24 and bore 94 to close off (as at 106) that part of the tube 76 which is disposed in section 12, the pressure which is applied through the bore 94 being considerably higher than is needed merely to collapse the tube 76 and have it act as a valve.
Fluid is discharged from the apparatus 10 by applying air through the bore 96 via the regulator 32, solenoid valve 36 and conduit 26 at a pressure which is intermediate of the pressures applied through the bores 94 and 98, respectively. Thus, as shown in FIG. 4, the pressure applied through the bore 96 is suflicient to collapse the tubing 76 in section 14, as at 108, for example, forcing the expansion, as at 110, of the previously closed part of the tube 76 which lies in section 16. Because the pressure exerted through the bore 94 is higher than the pressures exerted through either the bore 96 or the bore 98, the tube 76 remains valved closed (at 106) as fluid is expelled a from the apparatus 19 through the end 22 of the tube.
The time at which pressure is applied to sequentially collapse the tubing 76 in the sections 12, 14 is determined by the position of the cams Sfl, 52 of the timer 46.
The timing sequence of operation of the pumping apparatus 10 is relatively simple. Air is constantly applied through the bore 98 to the part of the tube 76 lying within the section 16 at sufficient pressure to flatten the tube (as at 104) to prevent passage of fluid past the flattened part 104 under the normal pressure head exerted against that part due to back pressure or the pressure at which fluid is supplied to the apparatus 16 from the reserovir 26.
The timer 46 operates to cause compressed air to be applied to the bore 94 to collapse the tube 76 as at 1136 and keep it collapsed while air at a pressure greater than in bore 98 but less than in bore 94 is applied through bore 96 to collapse or at least partly collapse the tube 76 (as at 108), forcing the valved tube at 104 to open to permit the expulsion of fluid from the appartaus 10. Pressure is then released on the bores 94, 96 to permit flow into the device of additional fluid to be pumped. As pressure is released from the bores 94-, 96, the air escapes through vents 100, 102 in the solenoid controlled valves 38, 36, respectively.
While the body sections 12, 14, 16 and the end plates 72, 74 are made of polystyrene in the example described above, other suitable materials of construction such as other rigid plastics, metals or even wood may be used.
It is likewise practical to substitute other gases for compressed air or to sequentially close the tubing 76 in the various sections by means of pressurized liquids.
The quantity of fluid moved by the pumping mechanism 10 may be adjusted by varying the diameter of the tube 76, increasing the length of that portion of the tube 76 lying between the sleeves 80, 82 in the section 14, or by altering the timing sequence to increase or decrease the number of times per unit of time that the tube in the section 14 is collapsed, for example.
Because of the resilient nature of the tube 76, usually made of rubber, for example, the valving action in the sections 12 and 16 will hold even though small particles may exist in the fluid which is being pumped.
While it is usually considered that liquids are to be pumped by this device, it will serve Well as a gas pumping device.
It is also apparent that the pumping apparatus of this invention may easily be disassembled and repaired. Should the tube 76 fail, replacement of the tube can easily be made. Because no moving part of the device except the tube 76 contacts the fluid being pumped, seals are no problem.
The amount of fluid pumped with each closing of the part of the tube in the section 14 has been found to be constant. Also, it has been found that the release of air pressure as the collapse of the tube 76 is Wanted helps to cool the tube 76.
In describing the pumping apparatus in conventional terminology, the section 12 is referred to as the input or suction section, the section 16 as the discharge section, and the section 14 as the working section.
What is claimed is:
1. Pumping apparatus comprising three block-like body members having opposed surfaces, each of said body members having a bore extending between said opposed surfaces, a collapsible resilient walled tube, said tube being threaded through each of said body members in sequence, means Within said tube adjacent to each of said opposed surfaces for maintaining substantially constant the inner diameter of that part of said tubing which lies adjacent to said opposed surfaces, a plurality of seal means, one of said seal means being disposed between the wall of each bore and the outer wall of said tubing adjacent to said opposed surfaces, said seal means closing the space between the tubing and the Wall of the bore adjacent to said opposed surfaces, a second bore in each member, said second bore communicating with the bore through which said tube extends, the first of said body members along said tube being the input member, the second of said body members along said tube being the pumping member and the third of said members being the output member, means for applying sufficient fluid pressure through the second bore in the output member to collapse said tubing in said member and close it to the passage of fluid in said apparatus which is at any input pressure or back pressure on said apparatus, and control means including a source of pressurized fluid for sequentially applying fluid pressure to said second bore in said input member at a pressure substantially in excess of that which is sufiicient to collapse said tube and close it to the passage of fluid, then, while maintaining said tube in the input member in said last mentioned condition, applying a lesser fluid pressure through the second bore of said pumping member to at least partially collapse said tubing in said pumping member and at least momentarily force open the closed collapsed tubing in said output member and then relieving the fluid pressure applied to the second bores of said input and pumping members.
2. Pumping apparatus in accordance with claim 1, wherein said body members are contiguous to one another in side by side relationship.
3. Pumping apparatus in accordance with claim 1, wherein said pressurized fluid is air.
4. Pumping apparatus in accordance with claim 1, wherein said tubing is rubber.
5. Pumping apparatus in accordance with claim 1, wherein said control means includes timer actuated solenoid valves coupled to said source of fluidized pressure which is applied to the second bores of said input member and the second bore of said pumping member.
6. Pumping apparatus in accordance to claim 1, wherein one end or" the tube is coupled to a source of fluid to be pumped and the other end of .the tube is adapted to be coupled to utilization means.
7. Pumping apparatus in accordance with claim 1, wherein all of said bores between said opposed surfaces are of the same diameter.
References Cited in the file of this patent UNITED STATES PATENTS 2,291,912 Meyers Aug. 4, 1942 2,769,397 Bolger Nov. 6, 1956 3,039,309 Vesper et al. June 19, 196-2