US3120817A - Pumps - Google Patents

Description

Feb. 11, 1964 Filed April 37. 1961 R. H. PRICE ETAL INVENTOPS P/c/mrd Hecror Price 8 Char/es Pay Jar/eff A TTORNEY R. H. PRICE ETAL Feb. 11, 1964 PUMPS 6 Sheets-Sheet 2 Filed April 27, 1961 IN VE N TOPS Richard Hecfor Price 8 Char/es Roy Jan-err B) a z WM ATTORNEY Feb. 11, 1964 R. H. PRICE ETAL 3, 7

PUMPS Filed April 2'7, 1961 6 Sheets-Sheet 3 /N I/E N TOPS Pic/ward h'ecfor Price 8 Char/es Roy Jarneft BY 4 2 flAc A ATTOPNEY Feb. 11, 1964 Filed April 2'7, 1961 R. H. PRICE ETAL -PUMPS Fig. 4.

6 Sheets-Sheet 4 /N VE' N TOPS Richard Hecfor Price, &. Char/es Roy Jarrerf BY A Z ATTORNEY.

Feb. 11, 1964 Filed April 27, 1961 R. H. PRICE ETAL PUMPS 6 Sheets-Sheet 5 N VE N TOPS Richard Hecfor' Price & Char/es Roy Jar/eff BY fii/M ATTORNEY Feb. 11, 1964 Filed April 27, 1961 R. H. PRICE ETAL PUMPS 6 Sheets-Sheet 6 N VE N TORS Pic/lard Hecfbr Price 8: Char/es Pqy Jar/eff BY Z {924 A TTOPNEY.

United States Patent Ofiice 3,l20,8l7 Patented F eb. 11, 1964 3,120,817 PUMPS Richard Hector Price and {Jharles Roy Jarrett, Cwmbran,

England, assignors to Saunders Vaive Company Limited, Cwmbran, England, a British company Filed Apr. 27, 1961, Ser. No. 105,937 Claims priority, application Great Britain Apr. 28, 1960 7 Claims. (Cl. 103-228) This invention relates to positive displacement pumps for services in which high pressures are not necessary. One purpose is to provide a valve assembly which is simple in construction; and which may be used in the presence of chemically aggressive fluids.

According to the invention the valve assembly comprises a rigid inlet valve coacting with an inlet seating, a resilient apertured outlet valve seating against the back of the inlet valve under its own resilience and thereby providing a closure between the valve housing and the aperture and serving lightly to bias the inlet valve towards its seating, the pumping chamber communicating with a space outside the aperture in the outlet valve and extending between the valves, During the suction stroke the inlet valve moves away from its seating against the light bias of the resilient outlet valve, while during the delivery stroke the pressure developed in the pumping chamber pressing on the part of the outlet valve outside the aperture lifts the outlet valve away from its seating on the inlet valve and the fluid is discharged through the aperture and out of the pump.

It will be seen that the delivery pressure as well as acting on the inlet valve over the whole area of the outlet valve, always has access to the back of the inlet valve through the aperture in the outlet valve and accordingly unless the suction stroke of the pump reduces the pressure in the pumping chamber and the delivery passage, the inlet valve will not open. Thus the valve assembly ac cording to the invention automatically causes the pumping to cease when the delivery pressure determined by the parameters of the pump is reached and excessive pressures cannot be developed.

Both valves are conveniently of circular outline. The inlet valve may be substantially a disc, with a rib on one face to cooperate with a fiat inlet seating surrounding an inlet part (or group of small parts) and with an annular rib of smaller diameter on its back terminating in a flat surface to serve as the seating for the outlet valve.

The resilient outlet valve may be in the form of an inner cylindrical portion defining the aperture, joined to a peripheral fiat marginal annulus by a U-sectioned convolution. The marginal annulus may be sealed to the valve chamber about the outlet port (or a group of small ports) by means of a cage or spider which may at the same time serve to centre the inlet valve. The free end of the cylindrical portion of the outlet valve may be thickened to increase the annular area which coacts with the seating on the back of the inlet valve.

The parts making up the valve assembly, that is the inlet valve, the resilient outlet valve and the cage may be made of materials which will not be attacked by any chemically aggressive fluids which are to pass through it and the valve casing and pumping chamber may be lined with a protective coating in a well known manner. To the same end the pumping member may be a diaphragm suitably reinforced which can be made of or faced with similar material to the outlet valve. The diaphragm or its facing is made inperforate so that it completely shields the operating mechanism from the pumped fluid.

Although the valve assembly according to the invention provides for limiting the delivery pressure and thus unloading the moving parts and driving mechanism if the delivery is restricted or cut off, for instance by the filling of a closed vessel, or the closing of a valve, additional provision of known character may be made in the operating mechanism. This provision consists in effecting the suction stroke positively and the delivery stroke by an operating spring. Thus if the valve assembly should fail to afford the necessary relief or under certain other conditions (determined for example by the delivery pressure, the area of the aperture in the outlet valve and the strength of the operating spring). The unloading may be effected by the additional provision in which case the operating spring simply remains loaded and the diaphragm in the position corresponding to the: end of the suction stroke even though the mechanism continues to operate.

Provision may be made to avoid chatter and noise when the unloading is efiected by the diaphragm remaining in the position corresponding to the end of the suction stroke. To this end the operating mechanism includes a slipper engaged (preferably through a roller) by the crank pin of a rotating operating crank. While the pump is operating a butler spring urging the slipper towards the crank pin remains stressed and the slipper operates the diaphragm actuator through resilient abutments but when the diaphragm remains in the position corresponding to the end of the suction stroke the slipper still remains in contact with the crank pin, the movement being taken up in the buffer spring so that there is no striking of parts in relative motion, while any backlash is also taken up by the springs.

The invention will be further described with reference to an embodiment illustrated solely by way of example in the accompanying drawings in which:

FIGURE 1 is an end view with the upper part in section of a complete pump according to the invention.

FIGURE 2 is a side view of the same pump with the lower part in section,

FIGURE 3 is a sectional side View on a larger scale of the valve assembly with the valves in the suction stroke position,

FIGURE 4 is a similar view to FIGURE 3 with the valves in the delivery stroke position.

FIGURE 5 is an axial section of a detail and FIGURE 6 is an end view of FIGURE 5.

IGURES 7 and 8 are details of modifications.

The illustrated example is a diaphragm pump. The diaphragm 11, as in diaphragm valves of well-known type, is clamped at its margin and is fixed between an outwardly bowed position (FIG. 3) and an inwardly bowed position (FIG. 4) by which means of a compressor 12 to which the diaphragm is attached by the aid of a screw stud 13 having its head embedded in a boss in the diaphragm, the face of the compressor being shaped to give support to the diaphragm over almost its whole area when it is inwardly bowed. During movement in the outward direction the support diminishes from the periphery inwards, but since this is the suction stroke this is not of importance. The total maximum stroke and gen eral proportions of the diaphragm are such that the small support at the beginning of the delivery stroke does not produce undue stresses or unduly shorten the life of the diaphragm which may have embedded fabric reinforcement.

The casing of the pump i.e. the part below the diaphragm, constituting the pumping chamber and thevalve housing is made up of two parts, an inlet part 14 and an outlet part 15 which incorporates the flange 16 against which the diaphragm is clamped. The inlet part 14 is spigoted into the outlet part 15 and secured by bolts 1'7. The two parts have respective bores 18, 19 in line and are constructed for connection in a pipe line or to tanks or the like, in this embodiment exemplified by the provision of end flanges 21.

In the inlet part 14 is formed a flat seating 22 for the inlet valve 23 which is generally of disk form with a rib 24 cooperating with the seating 22 and with a flat surfaced annular rib 25 in its back. The inlet valve is of rigid material.

The outlet valve comprises an inner substantially Cylindrical tubular portion 26 with flat end cooperating with the seating formed by the rib 25. This portion 26 is continued by a U-sectioned convolution 27 which connects it to a flat marginal annulus 238. The outlet valve is of resilient material, suitably of the same material as the diaphragm and it may similarly be reinforced. Its form is such that in the normal position shown in FIG. 2, it is slightly strained elastically under its own resilience by the flat end of the portion 26 pressing against the rib 25 and thus not only closes olf the outlet passage formed by the portion 26, but also presses the inlet valve 23 towards the seating 22 thus lightly biasing the inlet valve to closed position. Thus both valves are closed in this position. The marginal annulus 2c of the outlet valve is sealed to a facing 29 in the valve casing by a cage or spider (shown in detail in FIGS. and 6) which comprises a recessed rim 31 and a plurality of lugs 32. The dimensions are such that the lugs 32 are abutted by the spigot of the casing part 14 when the latter is bolted in place and the rim then locates and compresses the annulus 28 against the facing; the lugs also serve to centre 1e inlet valve 23 in relation to its seating 22 and the bore 18. Behind the outlet valve the part 15 is recessed at 33 so that when the valve is closed there is clearance within the facing 29 and behind the U-section convolution 27.

It will be seen that the pressure in the delivery bore 19 always has access to the back of the inlet valve. When the valves are closed this access is through the tubular portion 26 and is confined to the area within the rib 25. It supplements the resilient pressure of the outlet valve on the inlet valve. On the suction stroke, if the pressure in the outlet bore 19 is below a certain value (determined by the relative areas of the front of the inlet valve within the rib 24 and the back of the inlet valve within the rib 25, and by the resilient pressure of the outlet valve) the inlet valve opens automatically, further elastically straining the outlet valve which remains closed against the seating 25. Fluid enters the pumping chamber.

If the pressure in the inlet bore 18 is insuflicient, or in other words if the pressure in the outlet bore is above a certain value, the inlet valve does not open, no fluid enters the pumping chamber and the pump is unloaded.

If fluid has entered during the suction stroke, at the end of this stroke the bias on the inlet valve closes it and during the delivery stroke the pressure in the pumping chamher having access to the back of the inlet valve outside the rib 25 to start with holds the inlet valve closed all the more firmly. The delivery pressure also acts on the U-section convolution 2'7 so lifting the outlet valve away from the seating 25. An annular passage is thus opened between the seating 25 and the end of the portion 26 of the valve, and the fluid is displaced through this space and out through the tubular portion 26 and thence through the bore 1?, as shown by the arrows in FIG. 4. The recess 33 is made of such shape and depth that it forms a check which limits the opening of the outlet valve to a value wlL'ch avoids excessive deformation. Avoidance of deformation is assisted by making the tubular portion 26 thicker in the wall than the convolution 27; this also increases the width of the flat end which cooperates with the seating 25.

Although the valve assembly provides for unloading of the pump if the delivery pressure rises above a certain value, the operating mechanism is also arranged to provide for unloading by leaving the diaphragm in the position of FIG. 3 if the pressure in the delivery bore and hence in the pumping chamber rises above a certain value. The mechanism in the illustrated embodiment comprises a crank 3 the pin 35 of which carries a roller 36 co-operating with a slipper 37 which at all times is held in con tact with the roller by the aid of a butler spring 33. The slipper 3'7 co-operates through embedded rubber buifers 39 with projections a l on an abutment 42 against which an operating spring bears and which is itself pinned or similarly secured to a spindle 44 pinned or similarly secured to the compressor 12 acting on the diaphragm ll. The slipper 37 is slidable on this spindle 44 and is urged towards the roller by the buffer spring 38 abutting against one abutment 45 fast to the spindle 41 and another 46 slidable on the spindle and transmitting its pressure through a pair of pins 1-7 parallel with the spindle and guided in apertures in the abutment 42 against which the operating spring bears.

The other end of the operating spring 43 bears against an abutment 43, the position of which is conveniently adjustable, in this example by a screwed sleeve 49 screwing into the upper end of a casing 51, and the upper end of the spindle 44 is conveniently guided in the sleeve The crank shaft 52 is shown journallcd in ball bearing 53 in a housing 54 secured to the side of the mechanism casing 51.

In operation as long as pumping is taking place on the suction stroke the crank positively displaces the slipper 37, and through the buffers 39 and pins 41, the abutment 42 and hence the spindle 44, compressor 12 and diaphragm ll; at the same time, th operating sphing 43 is compressed, and through the pins 47 and abutment 46, the slipper 37 compresses the buffer spring During the delivery stroke, the slipper 37 follows the roller 36 under the pressure of springs 43 and 38 and the pressure of spring 43 through the abutment 42 moves the spindle 44 and thus displaces the diaphragm ll.

if the presure in the pumphig chamber is above a certain value, when the crank rotates to carry the roller 36 in what would be the delivery stroke, the pressure of the spring 43 is insuflicient to displace the abutment 42 and therefore the spindle 44 and the diaphragm ll. But the slipper 37 being free on the spindle 4-4 and being under the pressure of the buffer spring 38 through the abutment 4-6 and pins 4 7, the slipper remains in contact with and follows the roller 3:6. in this way the slipper is held under all conditions against the roller 36, backlash is taken up, chatter and noise are avoided, and at no time is there any striking together of metallic relatively moving parts. As soon as the delivery pressure permits the operating spring 43 will displace the abutment 42 and the diaphragm and the pins 41 will come into contact with the pads 3?. This may be while the parts are in relative movement but the pads 39 are resilient and avoid any shock.

Although the diaphragm l1 completely isolates the mechanism from the pumped fluid, the casing 53. for the mechanism may be separate from a compartment 55 in which the compressor 12 is contained, the spindle 4-4 passing through a stufling boX so and its upper end may pass through a packing ring 57 into the sleeve 49. The stufling box and packing ring serve to retain lubricant and there may be a drain cock or plug 58 at the lower end of the casing fil just above the level of the stufflng box 56, and there may be a further cock or plug 59 to facilitate bringing the lubricant up to a particular level.

In the example shown, the casings 51, 55 have been made separate and bolted together, while the casing 55 incorporate a flange oil by which the margin of she diaphragm is clamped (by the aid of bolts 6-2) to be flange 16. The flange 61 is shown of angle section to confine the edges of the diaphragm and limit the compression of the diaphragm.

The drawings also show the casing part l4, 15 provided over the whole surface with which the pumped fluid comes in contact, with a lining 63. By means of such a lining for example of glass, rubber, synthetic rubber or plastic of appropriate quality, the casing can be made of cheap material and the pump deal nevertheless with chemically aggressive or difficult lluids, and the diaphragm will be made of or faced with a material selected according to the fluid to be pumped. In suitable cases the facing can be dispensed with as indicated in FIGS. 3 and 4.

Since the operating mechanism above described serves to unload the pump when the delivery pressure reaches a predetermined value irrespective of the action of the valves above described, this mechanism can also be used with valves which do not automatically unload the pump when such delivery pressure is reached. Two such modifications are shown in FIGS. 7 and 8.

In FIG. 7 the valves are of ball form, 64 being the inlet valve and 65 the outlet valve. In each case the valve cooperates with an angle section seating 66 and the valve ball is made of or faced with a relatively hard material Which will resist action by the fluid to be pumped. The valves here are gravity actuated but springs could be used.

The inlet and outlet passages at the valve seatings are directed at 45 to the vertical and a separate connection, 67 at the inlet and 68 at the outlet, is bolted-on which embodies a bend of 45 thus bringing the inlet and outlet to the honizontal. These connections are held each by two diametrically opposite bolts (one shown at 69), so that they can be turned through 180, bringing the respective passage to the vertical as indicated in broken lines.

In FIG. 8 the valves 71 are of disc form, each having a stem 72 passing through a hole in a stirrup 73 by which the valve is centred and guided. The stirrup is integral with an annlus 74 clamped by the bolted-on end connection 75. In the case of the inlet valve and the end conmection also holds in place an annular seating 76. As in FIG. 7 the valves are gravity operated but could be provided with springs.

In both FIGS. 7 and 8 the valves and associated parts exposed to the fluid are of material suitable for the service in view, e.g. rubber, synthetic rubber, or some inert material such as polytetrafiuoroethylene. The diaphragm and operating mechanism can be identical with those above described with reference to FIGS. 1 to 4.

It should be mentioned that a diaphragm is not the only possible positive displacement member of the pump but is one having great advantages for the purposes contemplated, in particular in completely isolating the mechanism from the pumped fluid.

We claim:

1. A positive displacement pump comprising a pumping chamber, means for imposing a cyclic change in volume on the chamber whereby its volume is alternately increased and decreased, an inlet passage opening into said chamber, an inlet seating at the junction of said passage With said chamber, a rigid inlet valve coacting with said inlet seating, an outlet passage aligned with said inlet passage and opening out of said chamber, an apertured outlet valve sealed at its periphery to the junction between said outlet passage and said chamber, the edge of the aperture in said outlet valve being adapted to seat on the back of said inlet valve, said outlet valve then closing said chamber from said outlet passage while permitting fluid pressure in the outlet passage to act through said aperture on said inlet valve over the area within said aperture, and resilient means urging said outlet valve towards the position in which the edge of its aperture seats on the back of said inlet valve and it lightly biases said inlet valve towards said inlet seating.

2. A pump according to claim 1 in which both said valves are of circular outline.

3. A pump according to claim 1 in which the outlet valve is itself of resilient material, its own resilience serving to seat the edge of its aperture against the back of the inlet valve and to bias the inlet valve.

4. A valve assembly according to claim 3 in which the outlet valve is in the form of an inner cylindrical portion defining the aperture, joined to a marginal annulus by a U-sectional convolution.

5. A pump according to claim 4 also including a cage pressing said marginal annulus whereby it is sealed to the junction of said outlet passage with said pumping chamher.

6. A pump according to claim 5 in which the cage serves to centre and guide the inlet valve.

7. A pump according to claim 1 in which the inlet valve is substantially a disc with a rib on one face to cooperate with the inlet seating, and with a rib of smaller diameter on its back to serve as the seating for the outlet valve.

References Cited in the file of this patent UNITED STATES PATENTS 122,544 Westinghouse Ian. 9, 1872 2,288,347 Flint June 30, 1942 2,349,135 Brassel May 16, 1944 2,569,734 Saalfrank Oct. 2, 1951 2,812,722 Reed Nov. 12, 1957 FOREIGN PATENTS 1,183,582 France Jan. 26, 1959 1,228,612 France Mar. 14, 1960 392,150 Germany Nov. 18, 1922

Claims (1)

1. A POSITIVE DISPLACEMENT PUMP COMPRISING A PUMPING CHAMBER, MEANS FOR IMPOSING A CYCLIC CHANGE IN VOLUME ON THE CHAMBER WHEREBY ITS VOLUME IS ALTERNATELY INCREASED AND DECREASED, AN INLET PASSAGE OPENING INTO SAID CHAMBER, AN INLET SEATING AT THE JUNCTION OF SAID PASSAGE WITH SAID CHAMBER, A RIGID INLET VALVE COACTING WITH SAID INLET SEATING, AN OUTLET PASSAGE ALIGNED WITH SAID INLET PASSAGE AND OPENING OUT OF SAID CHAMBER, AN APERTURED OUTLET VALVE SEALED AT ITS PERIPHERY TO THE JUNCTION BETWEEN SAID OUTLET PASSAGE AND SAID CHAMBER, THE EDGE OF THE APERTURE IN SAID OUTLET VALVE BEING ADAPTED TO SEAT ON THE BACK OF SAID INLET VALVE, SAID OUTLET VALVE THEN CLOSING SAID CHAMBER FROM SAID OUTLET PASSAGE WHILE PERMITTING FLUID PRESSURE IN THE OULET PASSAGE TO ACT THROUGH SAID APERTURE ON SAID INLET VALVE OVER THE AREA WITHIN SAID APERTURE, AND RESILIENT MEANS URGING SAID OUTLET VALVE TOWARDS THE POSITION IN WHICH THE EDGE OF ITS APERTURE SEATS ON THE BACK OF SAID INLET VALVE AND IT LIGHTLY BIASES SAID INLET VALVE TOWARDS SAID INLET SEATING.

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