US 3082698 A
Description (OCR text may contain errors)
March 26, 1963 E. M. SMITH 3,0
PUMP OPERATED ON PRESSURE DIFFERENTIAL Filed April 9, 1959 IN V EV TOR.
EDWARD [1. SMITH cm ATTORNEY United States Patent 'ce 3,082,698 PUMP OPERATED 0N PRESSURE DIFFERENTIAL Edward M. Smith, Mansfield, Ohio, assignor to Techno Corporation, Erie, Pa, a corporation of Pennsylvania Filed Apr. 9, 1959, Scr. No. 805,158 Claims. (Cl. 103-435) This invention relates to pumps and, more particularly, to pumps having no moving parts.
In pumping liquids containing suspended solids which may be damaged by the moving parts of a pump, it is desirable to have a pump which has no moving parts come in contact with the liquid and the solids therein. The pump covered by this invention has no moving parts inside the pumping element. This makes it advantageous in pumping products which contain matter which might be damaged from shear or turbulence introduced by a pump of the conventional type. This also permits the interior of the pump chamber to be lined to prevent corrosion and contamination and provides a long life of apparatus parts in handling materials having abrasive matter suspended therein.
Some materials which may be successfully handled by the pump disclosed herein which cannot be handled by ordinary pumps are chemical slurries and liquids having abrasive materials suspended in the liquid; food products, for example, fruits; and miscellaneous materials such as fly ash, latex, paints, refuse in suspension, and sewage.
The pump is controlled by a balanced diaphragm which is actuated by the static head imposed on it by the material being pumped. No floats are necessary and the operational force is introduced from a compressed air source. In several of the embodiments disclosed herein, the pump operates intermittently; however, in one embodiment, the pump is arranged to pump a constant output by having duplex chambers.
The pump disclosed herein requires no foundation for support, no water or electrical connection, it is highly portable, and it may be used for a variety of pumping applications. The pump may be installed simply by connecting the suction and discharge lines and the air lines. Since no electrical connect-ions are necessary, the pump is entirely safe and it is suitable for use in explosive atmospheres. It is suitable for environments where other types of pumps might create a hazard due to moving parts.
Basically, the pump in its simpler form consists of a tank or pressure vessel with a source of compressed air connected to the top of the tank or vessel. The tank or vessel may be made in various shapes. At the bottom of the tank are an outlet valve and an inlet valve. The bottom of the tank is connected to one side of a sensitive diaphragm. The diaphragm is connected to the pilot of a tour connection valve.
Assuming that the tank is filled with liquid and the compressed air is applied to the top of the tank, the compressed air forces the material through the discharge valve and keeps the inlet valve in the closed position. As the material in the tank is discharged, the pressure head will be reduced and the loss of the static head in the tank produces a differential pressure on the diaphragm. The diaphragm then operates to open an ejector. This ejector then evacuates the pump tank. As a vacuum is developed, the discharge valve closes and the inlet valve opens. When the inlet valve opens, material flows into the pump tank because of the vacuum created. When the material reaches a predetermined level in the pump tank, the diaphragm again becomes unbalanced because of the difierential created by the hydraulic head in the tank. When the diaphragm becomes unbalanced, it reverses the cycle and admits air pressure to the top of the 3,@82,6% Patented Mar. 26, 1953 tank again which 'forces the liquid out and the cycle is repeated.
More specifically, it is an object of this invention to provide a pump which overcomes the disadvantages in prior pumps having moving parts and, more particularly, it is an object to provide a pump which is simple in construction, economical to manufacture, and simple and efiicient in operation.
Another object of the invention is to provide a pump which will pump liquids without any moving parts in contact with the liquids.
A further object of the invention is to provide a pump wherein compressed air is used as the pumping force.
With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.
In the drawing:
FIG. 1 shows a pump according to the invention with a compressed air and fluid supply circuit connected thereto;
FIG. 2 shows an alternate embodiment of the invention;
FIG. 3 is a view of another embodiment of the invention; and
FIG. 4 is still another embodiment of the invention.
Now with more specific reference to the drawing, FIG. 1 shows a pump in having a pump tank 18. The pump 10 transfers liquid from a supply tank 39 through a pipe 11 to an outlet 14. The supply tank 30 is connected to the pipe 11 by an inlet 12. The pipe 11 is also conneoted to the lower side of a diaphragm 24 and to the pump tank 18 by way of a discharge 17. The supply tank 35 is located at a higher elevation than the maximum level to which a surface 28 of liquid in the tank 18 is expected to rise.
The tank or reservoir 18 may have a lining made of a corrosion or abrasion resistant material, depending on the nature of the material to be pumped. The pipe 11, the tank 34 the diaphragm 24, and all other parts which contact the liquid may also be made of similar material.
A compressed air line 21 is selectively connected to a line 19 when the liquid level 28 has risen to a level suificient to impose a static head on the lower side of the diaphragm 24 to cause it to overcome the force of a spring 23. This will shift a pilot of a valve 27 from the position shown. Since the pilot is connected to the diaphragm 24 by a connector 25 when the valve 27 is shifted, the line 21 will thus be connected to the line 19 for the discharge stroke of the pump 10.
In the position of the valve 27 shown in FIG. 1, the tank 18 will fill. This may be considered as its intake stroke. In this position, a line 20 exhausts to atmospheric pressure by the valve 27 connected to the line 19. In this intake position, back pressure from fluid which has been pumped to the outlet 14 will close a check valve 16. Fluid pressure from the supply tank 3% will cause fluid to how by force of gravity through a check valve 15 and through the discharge 17 into the tank 18, forcing air to be discharged through a float valve 31, the line 19, the valve 27, to the exhaust line 20.
Since the space in the tank 18 over the top of the liquid level 28 is connected by the line 19 to a chamber 22 above the diaphragm 24 and since the space below the diaphragm 24 is connected to the pipe 11, there will be a difierence in pressure above the diaphragm 24 to that below the diaphragm 24. This difference in pressure will be equal to the static head of the liquid in the tank 13 above the level of the diaphragm 24-. This static head will increase as liquid flows from the tank to the tank 18 until the static head overcomes the force of the spring 23. At this point, the diaphragm 24 will shift the pilot of the valve 27 and connect air from the line 21 to the space above the liquid in the tank 18 for the discharge stroke.
In the embodiment of tr e invention shown in FIG. 2, a pump 11%) is shown similar to that shown in FIG. 1. The pump 116 has a tank 113 connected to a pipe 111 by a discharge 117. The pipe 111 communicates from a source of liquid to be pumped indicated at 112 to a discharge 114. Check valves 115 and 116 are connected in the pipe 111. A chamber 122 has a diaphragm 12 1 with the lower side of the diaphragm 124 connected to the pipe 111 and the upper side connected to a line 119. T he diaphragm 124 is urged downwardly by a spring 123. A valve 127 is a four connection pilot controlled valve having its pilot connected at 125 to the diaphragm 124.
in the deactuated position shown which is the intake position, the valve 127 connects the line 119 to a line 129, a check valve 129, and to a vacuum pump 130. In this position, the vacuum pump 13% Will draw liquid from the pipe 111 into the tank 118 to raise the level indicated at 128. When the level 128 has risen to a height which will impose a pressure head on the diaphragm 124 which will overcome the force of the spring 123, the valve 127 will be shifted to an actuated position and air pressure from a line 121 will force the liquid from the tank 118.
The embodiment shown in FIG. 3 is exactly like that shown in F16. 2 except that in FIG. 3, an educer 231' is provided instead of the vacuum pump shown in FIG. 2. The educer 231' is made up of a venturi 230 which has a suction pipe 221 connected thereto. In the position shown, the suction pipe 220 is connected to a line 219 by a valve 227 and the pressure pipe 232 of the venturi 230 is connected to an air pressure line 221. In this position, the educer 231' will reduce the pressure above a liquid level 228 which will draw liquid from a pipe 211 into a tank 218. When the liquid head in the tank 213 reaches sufficient magnitude to overcome the force of a spring 223, the valve 227 will be shifted to connect the line 221 to the line 219. This will connect air to the tank 218 by way of the line 219 to force liquid from the tank 218 to a discharge 214.
FIG. 4 shows a duplex pump 310 wherein a substantially constant output from the pump can be obtained as opposed to an intermittent output from the other embodiments. Tanks 318 and 340 are connected together by a line 311 as shown. The tank 313 is connected to the line 311 by Way of an entrance chamber 317 and the tank 349 is connected to the line 311 by an entrance chamber 341. The line 311 has an inlet 312 and an outlet 314. The inlet 312 may be connected to a source of liquid at a lower pressure than the repository to which the outlet 314 is connected and fluid Will be pumped from the inlet 312 to the outlet 314.
A valve 327 is a four connection pilot controlled valve connecting a line 320 to a line 342 and a line 321 to a line 319 in the unactuated position. When the valve 327 is shifted by a pilot actuated by a diaphragm 324, the valve 327 will connect the line 321 to the line 342 and the line 319 to the line 3211.
In the actuated position, the top of the tank 340 is connected by a float valve 345 and the line 34-2 to the suction line 321) of a venturi 330 by the valve 327. The line 319 is connected to the pressure side of the venturi 330 and to the air pressure line 321 by the valve 327. The line 319 is further connected through a coat valve 331 on the tank 318 by means of throttling valves 343 and 344- which are connected in series with check valves 34-5 and 346, respectively.
Check valves 315, 315, and 316 are connected in series in the line 311 to allow flow from the inlet 312 to the outlet 314 and to prevent flow in the opposite direction. A diaphragm valve 322 is connected to an entrance chamber 317 through the line shown and fluid pressure from the entrance chamber 317 is impressed on the lower side of the diaphragm 324 by fluid in this line. A compression spring 323 is connected to the diaphragm 324 and rests against the body of the valve 322 above the diaphragm 324 as shown. The pressure head of liquid level indicated at 328 is impressed through the entrance chamber 317 through the line onto the lower side of the diaphragm 324. When this pressure head reaches a high enough value, it urges the diaphragm 324 upwardly against the force of the spring 3.3 to actuate the pilot to move the valve 327 from the position shown.
During operation, the inlet 312 is connected to a supply of fluid to be pumped and the outlet 314 to a repository. The valve 327 will be shifted by the pressure head from fluid from the tank 318 to the position shown at the time liquid in the tank 318 has risen to its maximum level and the tank 340 is almost empty. The line 319 will be connected by the valve 327 to a source of compressed air from the line 321. Air from the line 321 will flow through the valve 327, the line 319, the throttle valve 344, and the check valve 346 and the pressure will be impressed on the liquid level 328, forcing the fluid from the tank 313 through the check valve 316 to the outlet 314. The rate at which liquid is forced from the tank 313 can be controlled by adjusting the throttle valve 344 which will control the rate of flow of air into the tank 318. At the same time, air from the line 319 will also be flowing through the venturi 330 which will apply a suction to the line 320 and through the valve 327 to the line 342 through the float valve 345 to draw liquid from the inlet 312 through the check valve 315 into the tank 349.
When the liquid level 328 in the tank 318 has been reduced to the point that the force of the spring 323 on one side of the diaphragm 324 will overcome the force of the liquid on the other side of the diaphragm 324, the pilot will shift the valve 327 so that air pressure will be connected from the line 321 to the line 342 into the tank 340. The tank 341) will, at this time, be full of liquid which was drawn into the tank 340 while the tank 318 was being emptied, as previously described, and this will force the liquid from the tank 340 through the valve 315' and the line 311 to the outlet 314. At this time, the line 319 will be connected to the ambient atmosphere through the valve 327. A part of liquid forced from the tank 344) will flow into the tank 318 and liquid entering the tank 318 will force air through the check valve 345' and the throttle valve 343 from the tank 318 from above the liquid level 328 at a predetermined rate through the venturi 330, determined by the settling of the throttling valve 343. Thus, part of the liquid from the tank 340 will be forced up into the tank 313 to be discharged on the subsequent stroke. The other part of this liquid will be discharged through the check valve 316 to the outlet 314. When the level of liquid 1n the tank 318 has risen to a predetermined level, the pressure from the head thereof impressed on the diap lzigagm 324 will again overcome the force of the spring This cycle will repeat each time the head in the tank reaches a height suflicient to overcome the force on the spring 323 against the diaphragm 324 which will again shift the valve 327 so that the tank 313 will be emptied by air pressure from the line 321 when the valve 327 is in the position shown.
The foregoing specification sets forth the invention in its preferred practical forms but the structure shown is capable of modification Within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.
The embodiments of the invention in which an exclu sive property or privilege is claimed are defined as follows:
1. A pump comprising a tank, a member having an inlet and an outlet spaced therefrom, said member being connected to said tank at an intermediate part thereof, said outlet having a check valve allowing liquid to tiow from said tank but obstructing the flow of liquid to said tank from said outlet, valve actuating means connected to said member between said inlet and said outlet and sensitive to the pressure head of liquid in said tank, and a control valve, said valve actuating means being connected to said control valve, said control valve connecting a source of compressed air to said tank when said valve actuating means actuates it and disconnecting said source of compressed air from said tank when said control valve is deactuated.
2. The pump recited in claim 1 wherein said control valve connects a source of vacuum to said tank when said control valve is in a deactuated position.
3. The pump recited in claim 2 wherein said source of vacuum comprises a venturi having a pressure pipe and a suction pipe, said control valve connects a source of air pressure to said pressure pipe of said venturi, and said control valve connects said tank to said suction pipe of said venturi when said control valve is in the deactuated position.
4. A pump comprising a tank having a liquid line and a gas line, said tank having an opening connected to said liquid line at the bottom of said tank and an opening connected to said gas line at the top of said tank, said liquid line having a spaced inlet and an outlet with said tank communicating with said liquid line between said inlet and said outlet, at check valve at said inlet and another at said outlet, a source of liquid to be pumped to said liquid line connected to said inlet, actuating means connected to the bottom of said tank between said check valves controlled by the pressure head of liquid in said tank and connected to a control valve, a source of compressed gas, suction means, and control valve actuating means, said control valve actuating means being connected to said tank, said control valve being actuated by said control valve actuating means whereby said control valve is actuated to connect said source of compressed gas to said gas line when said pressure head reaches a predetermined value to force said liquid out of said tank into said liquid line, said control valve actuating means actuating said control valve whereby it connects said suction means to said gas line when said pressure head is reduced to a predetermined value to draw liquid into said tank from said liquid line.
5. The pump recited in claim 4 wherein said actuating means comprises a diaphragm and a member attached to said diaphragm and to said control valve, one side of said diaphragm being in liquid flow engagement with liquid at the bottom of said tank, the other side of said diaphragm being in liquid flow engagement with gas in said gas line.
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