US 2948221 A
Description (OCR text may contain errors)
Aug. 9, 1960 Filed May 22, 1957 P. w. CARVER 2,948,221
PUMPS FOR LIQUIDS 2 Sheets-Sheet 1 FIG].
AttorneyS Aug. 9, 1960 P. w. CARVER 2,948,221
PUMPS FOR LIQUIDS Filed May 22. 1957 2 Sheets-Sheet 2 Inventor by M AtforneyS United States Patent Office Patented Aug. 9, 1,960
PUlVIPS FOR LIQUIDS Philip Walker Carver, Nuthall, Nottingham; England, assignor to Kontak Manufacturing *Co. Ltd., Grantham,
Lincolnshire, England, a British company This invention relates to pumps of the diaphragm type in which the fluid to be pumped is'separated from a motive fluid by the diaphragm which is pulsated by alternate pressure and suction of the motive fluidsupplied by a suitable pump and valve system. Such pumps are used for metering liquids for which purpose the volume per stroke is readily adjustable. V I
According to this invention there is provided apump comprising a diaphragm in a chamber'the entire volume of which it sweeps on each delivery and'suction stroke, a one-way valve through which liquid is drawn into the pump chamber on the suction stroke, and another-onephragm to cause the diaphragm to reciprocate in its chamber and an electric motor driving therotating valve. Preferably means are provided for adjusting the pump delivery by adjusting the limit "of permissible travel of the diaphragm on the suction stroke.
The pressure and suction sources may be created by a' Preferably .both suction port and delivery port are above the moving element of the pump and communicate with them by passageways which are in part vertical, and on extensions of which are the said two valve controlled communications to the reservoir.
An example of this invention is illustratedin the accompanying drawings of which Figure 1 is a vertical sec tion througha diaphragm pump and changeover valves and Figure 2 is a like section through a rotary pump which provides the pressure and suction. sources and the associated deaerating device.
A pressure source and a suction source are created by a gear pump 110 andxare connected to a valve body indicated generally by the figure 10, the pressure source by a pipe 11 and .the suction source by a pipe 12.
In the valve chamber 10 are two barrel plug valves 13 and 14 which are driven in unison via a geared electric motor 15 so that pipes 16 and 17'which lead out of the valve body are placed alternately in communication with the pressure .side 18 and suction side 19 of the valve chamber. Pipes 16 and 17 communicate with the pump indicated generally at 20.
In this pump are two identical pump chambers 21 and 22 across which extend pump diaphragms 23 and 24. Movement inwards of either diaphragms, i.e. toward the centre of the pump chamber draws in liquid from pipe 25 through spring loaded valves 26 or 27 as'the case may beand movement outwards expels liquid into pipe 28 through spring loaded valve 29 or 30 as the case may be. Outward movement of the pump diaphragms is limited by end plates 31, 32 which have holes through them 33 and 34 and inward movement is limited by diaphragm members 35 and 36. These diaphragm members 35 and 36 consist'of resilient material peripherally secured along with pumping diaphragms, as shown, and supported by backingv plates 37 which constrain the diaphragm but rotary pump such as a gear or vane pump, with deaera:
tion, induction and relief arrangements providing a supply of liquid on whichthe pump may expend' energy, thus creating the suction and pressure sources; 1 j
The movement of the pump diaphragm may be limited by a support diaphragm which latter forms one wall of the pump chamber against which the pump diaphragm moves on the suction stroke and which is "displaceable to adjust or vary the extent of the diaphragm stroke;
permit it to move from one purely frusto-conical position to another as later described. 4
Pressure and suction communicated to the pump chambers by pipes 16 and 17 is communicated to chambers 38 and 39 on the inner side of the two diaphragms 35 The pump may comprise a pairof pump diaphragms in chambers connected to a valve body in which two valves are provided driven by the said motor'to connect alternately the sources of pressure and suction to each pump diaphragm.
In this case the stroke limiting supportldiaphra'gm may be spring loaded back on to a common stop which may be of tapered form and adjustable to force them apart or allow them to come together thus. altering'in unison thedelivery of the two pump chambers. More than one diaphragm pump unit may be driven from one actuating pump.
The deaerating arrangement may be provided by a reserve tank above the pump chamber which is not normally completely filled with liquid so that there is an air space above the liquid, a communication being provided from the reservoir to the suction side of the pump such communication being through a port opened and closed by a float in a chamber below the reservoir, the said port being above the suction port, another communication being provided through a loaded valve from the delivery side of the pump to the reservoir, the valve being situated above the delivery port.
Preferably a second connection is provided between the reservoir and the suction side of the pump through a loaded valve situated above the suction port.
and 36 and thence by holes 40 through the diaphragms to thediaphragms 23 and 24 and by these means the said diaphragms are caused to move alternately outward or inward thus sweeping the entire volume of chambers 21 and 22.
It will also be appreciated that while diaphragm 23 is on its suction strokediaphragm 24 is on the delivery stroke and vice versa. The rigid central disc portions 41and42 of the diaphragms 35 and 36 carry spindles 43 and 44 the ends of which are' held by springs 45 and 46 against a tapered member 47 carried by a threaded spindle 48'threaded into a flange 49 on the pump body phragms apart or raised to bring them together thus controlling the volume of the pump chambers.
A knurled head 50 may carry a scale which can be used to calibrate the pump delivery.
7 Turning. now to Figure 2 the gear pump driven by an electric motor 111 is'mounted in a pump chamber 112. The pumpcauses a continual suction in pipe 12 which communicates with the pump via a vertical conduit 114 and a continuous pressure in pipe 11 which communicates with the pump through a vertical conduit 115.
Situated above the pump chamber is a reservoir 117 filled with liquid the level of which is indicated at 118, thus providing an air space 119 above it which is vented by means not shown to the atmosphere.
Liquid can pass into the reservoir from pipe through spring loaded valve 120 and from the reservoir into vertical conduit 114 through spring loaded valve 121.
A further communication is provided between the conduit 114 and the reservoir chamber through a port 122 opened and closed by a valve element 123 carried by a float 124 floating in a chamber 125 which communicates through port 126 with the lower side of valve 121.
Air bubbles in the suction side of the pump will find their way to the float chamber 125 causing the level of the liquid in the chamber to fall, the float therefore to fall, opening the port 122 through which the bubbles will escape into the reservoir and oil will replenish the float chamber 125. Bubbles on the delivery side of the pump will pass into conduit 115 collecting under valve 120 which lies on the top of an extension 115a of conduit 115 above the pipe 11.
The system is so arranged that the valves 121 and 126 will open only on a greater suction or delivery pressure than that required to draw in liquid through valves 26 and 27 and pump it out through valves 29 and 30 against the head against which the diaphragm pump is delivering, but the displacement volume of the pump 110 is such that valves 121 and 120 will be continuously open and there will be a constant circulation through the reservoir 117 so that any bubbles will reach the reservoir through valve 120. The pump 110 is so arranged in relation to the diaphragm pump that thereis a fall between pump 110 and the diaphragm chamber to help to circulate bubbles in the system. A fall of 1 inch per foot has been found satisfactory.
1. A metering pump for delivering a measured quantity of liquid per unit of time comprising in combination, a housing having a compartment, a flexible diaphragm dividing said compartment into two chambers, the entire volumes of which it sweeps on each delivery and suction stroke, a one-way inlet valve and a one-way discharge valve connected to one of said chambers for handling the per-stroke measured quantity of pumped liquid, sources of continuous suction and pressure, valve means arranged to alternately connect said sources to the other of said chambers to cause the diaphragm to reciprocate in its compartment and means independent of the suction and pressure sources to actuate said valve means at a fixed speed. I
2. The metering pump as claimed in claim 1 in which said compartment has opposed walls each of substantially frusto-conical shape, the one of. said walls up to which the diaphragm moves on one stroke being flexible, means to move said last mentioned wall to vary the volume of the compartment swept by the diaphragm, said means substantially maintaining the frusto-conical shape of the wall whereby the diaphragm at one end of its stroke will rest against said wall with minor edge flexing.
3. A metering pump as claimed in claim 1 embodying two complete pumps as described and said valve means being arranged to connect the sources of suction and pressure alternately to one side of each diaphragm so that one is on its delivery stroke while the other is on its suction stroke and vice versa to effect substantially continuous delivery.
4. A metering pump embodying two complete pumps as claimed in claim 2, said valve means being arranged to connect the sources of suction and pressure alternately '4 to one side of each diaphragm so that one is on its delivery stroke while the other is on its suction stroke and vice versa, the two pumps being so disposed that the movable walls are adjacent each other, spring means urging said walls toward each other and single means to force the said walls apart to adjust delivery rate.
5. A metering pump as claimed in claim 4 in which the said valve means are two rotating valves each having a delivery side and an inlet side, means connecting the delivery side of each valve respectively to the adjustable wall side of a different one of said chambers, and means to alternately and oppositely connect the inlet sides of said valves to the said sources of suction and pressure.
6. A metering pump as claimed in claim 1 in which the sources of pressure and suction comprise a rotary pump system having a motor driven rotary pump of greater displacement volume than necessary to cause the said pump diaphragm to sweep both its chambers, a liquid reservoir for said rotary pump, a loaded valve connecting the pressure side of said rotary pump to the reservoir and a loaded valve connecting the reservoir to the suction side of the rotary pump whereby the excess displacement causes a flow through the loaded valves into and out of the reservoir.
7. A metering pump as defined in claim 6 including means co-operating with the reservoir and the suction side of the rotary pump to deaerate the liquid in the rotary pump system.
I 8. A- metering pump as defined in claim 7 in which the deaerating means includes the reservoir open to atmosphere and incompletely filled, an auxiliary passage between the reservoir and the suction side of the pump around said loaded valve which connects the suction side of the pump to the reservoir and including a port and a float chamber below the reservoir, a valve actuated by saidfioat to close or open the port to the reservoir, said port being above the connection between the suction side of the rotary pump and the diaphragm pump chamber.
9'. The metering pump as claimed in claim 8 in which the connections between the rotary pump inlet and outlet and the reservoir lie above the connections between said rotary pump inlet and outlet and the diaphragm pump chamber. 7
10. The metering pump as claimed in claim 9 in which the connections from the suction and delivery sides of the rotary pump to the diaphragm pump chamber are located vertically abovethe rotary pump, at least a part of each connection being vertical, extensions of said vertical parts leading to said loaded valves between the rotary pump and reservoir.
References Cited in the file of this patent UNITED STATES PATENTS