US3256825A - Slurry pump - Google Patents

Description

' June 21, 1966 s, UMPERT ET AL 3,256,825

SLURRY PUMP Filed Sept. 4, 1964 FIG. 1 FIG. 2

FIG. 4

lgk FIG.6

j INVENTORS.

7P ALEXANDER S. LIMPERT 04/ 4 I05 BY ROBIN J. LIMPERT 75 78 74 29 I07 ATTORNEY United States Patent 0 Filed Sept. 4, 1964, Ser. No. 396,794 20 Claims. (Cl. 103-44) This invent-ion relates to fluid devices, and more particularly to fluid displacement pumps of the type adapted to fluid actuation. This invention is a continuation in part of our copending applications Serial Nos. 84,735, filed Jan. 24, 1961, now issued as U.S. Patent No. 3,100,- 451, dated Aug. 13, 1963; 88,798 filed Feb. 13, 1961, now issued as U.S. Patent No. 3,128,782, on Apr. 14, 1964, and 143,465 filed Oct. 6, 1961, now abandoned.

Metering and proportioning pumps for the movement of chemical solutions and the like are known, in which a pumping impulse is provided to the pumping mechanism in the form of a fluid impulse, such as an oscillating flow of hydnaulic fluid in an actuating line connected to the pumping mechanism. This is a convenient arrangement,

' because the volume and the frequency of the pump strokes can be very accurately regulated by adjustment of the source of the fluid impulses.

The pumping mechanism itself is frequently a diaphragm actuated by the pumping impulses, and provided with inlet and outlet valves for the control of the flow of the pumped liquid.

Since the pumped liquid frequently is a chemical additive, which may often be in the form of a slurry, and frequently is in the form of a dissolved or diluted material, it is common for the pumping mechanism to be required to handle a liquid suspension of undissolved or insoluble particles, especially when it has pumped down toward the end of a batch or container-full of the additive material. Such particles are usually limited in size to those smaller than the mesh dimensions of. an appropriate inlet screen, so that blockage of the pump by a single large particle seldom occurs. Many of the suspended solids which it is desired to pump, however, display the inconvenient property of breaking out of suspension near regions of turbulence and building up on nearby parts of the pump.

When this occurs on the pump valves, and especially on the inlet valve, it causes it to leak thus destroying the metering accuracy of the pump, and it is not unusual for it to cause the inlet valve to refuse to close at all during some strokes of the pump, thus destroying its effectiveness.

Even in cases where such extreme consequences do not occur, many of these suspensions, such as those'of talc, chalk or ifullers earth, diatomaceous earth, are

highly abrasive, and result in a rapid wear and destruction of the pump valves and seats due to the erosive effect of the suspension when it flows through a partly closed valve at high velocity.

Another difliculty experienced in the construction of metering pumps is that if accuracy of measurement is desired, the pump valves must be designed to be as small as feasible. This is because, since they are necessarily provided with a resilient seal, the precise closed position of the valve is always somewhat in doubt because of the compressibility of the seal, which allows the valve to assume different positionsaccording to the pressure exerted upon it. Minimizing the size of the valve thus reduces, but cannot eliminate the changes in pumping chamber volumn arising from this cause, and accentuates all of the aforementioned difficulties due to suspended material in the pumped fl-uid, both because of the difliculty of construction such a small part with precision, and because of increased flow velocity and consequent erosion which such small size requires.

3,256,825 Patented June 21, 1966 We have discovered that all of these difficulties can be overcome, and the pumping mechanism rendered both more accurate, more reliable, and more durable by providing pressure actuated valves, and especially a pressure actuated inlet valve, which is relatively large in dimensions, and is driven between open and closed positions according to the fluid pressure impulse applied in the hydraulic chamber of the pump to the pumping chamber.

By doing so, the size of the valves may be increased to the degree necessary to ensure accurate and reliable operation, and the velocity of flow over the valve reduced to the point where excessive deposition of contaminants does not occur. Moreover, it becomes feasible to provide the valves and seats with a hard surface material or an inherently hard composition, which is highly resistant to abrasion. This is now possible because adequate positive valve seating pressure is available to ensure seating of the valve despite the presence of contaminants.

The invent-ion accordingly provides a pump for supplying fluid to a line comprising, in combination, a pump chamber, a pressure chamber, and a movable member such as a diaphragm or piston therebetween; bias means operatively connected to the movable member and normally retaining the member in a first position; fluid connections to the pumping chamber for flow of fluid to and from the chamber, and a fluid connection to the pressure chamber for flow of pressure fluid to the chamber to pulse the member against the action of the bias means, the bias means acting to restore the member to the first position upon reduction of fluid pressure in the pressure chamber; a valve and valve seat disposed across the line of fluid flow through the pump chamber for controlling the flow of fluid therein, the valve being reoiprocatingly mounted for movement between open and closed positions, respectively away from and toward the valve seat; fluid pressure-responsive means operatively attached to the.

valve, and a fluid connection communicating the fluid pressure responsive means with one of the chambers of the pump for'op'eration of the valve in response to fluid pressure in the said chamber.

Thus, upon increase in fluid pressure in the pumping chamber or in the pressure chamber of the pump, the increased pressure is communicated to the pressure responsive means, and caused to actuate the valve to a closed or open position, as desired. The valve can be an inlet valve, in which case it will normally be advantageous to communicate the pressure responsive means with the pressure chamber, and arrange it to drive the valve to a closed position upon increase in pressure therein. The valve can also be an outlet valve, in which case it will normally be advantageous to communicate the pressure responsive means with the pressure chamber in a manner to drive the valve to an open position upon increase in pressure therein. One or both of the pumping chamber valves can be pressure-actuated in accordance with the invent-ion.

The pressure responsive means of the invention can take any of several forms. A diaphragm is especially advantageous, and is preferred. The diaphragm can be of flexible material, such .as metal, for instance, stainless steel, iron, steel, aluminum, tin, nickel-chromium alloy, or copper, or plastic, such as polyam-ide, polytetrafluoroethylene, polycarbonate, polystyrene, polyethylene, or polypropylene. synthetic rubber, or a sheet spring, such as a Belleville spring disc or washer, aflixed to a piston-type or poppet valve. Rein-forcing support can be provided a diaphragm of structurally weak material.

A bellows also can be used, really a form of folded diaphragm, and made of any of the above materials.

In some uses, a piston means operated in a cylinder It can be resilient, such as rubber, or

is particularly desirable. A piston can be combined with a diaphragm to increase the surface area open to pressure actuation and improve sensitivity.

It is usually advantageous to utilize the initial and terminal reduced pressure portions of the pressure impulse for inlet valve actuation, while reserving the central higher pressure portion for pump chamber contraction. This can be accomplished by providing bias means for the valve, such as a tension or compression spring, of appropriate design and resiliency. The inherent resiliency of the valve actuating member, such as a stainless steel diaphragm, may be employed to like purpose. A Belleville washer can be used to retain the valve in either the open or the closed positions, to ensure return of the valve to one of such positions in response to change in fluid pressure. A magnetic pressure responsive means can be used, attracted to a corresponding magnetic means at the position at which the valve is to be retained. One or both of such magnetic means can be magnets.

It is also feasible to forego the employment of bias means and employ only pressure actuation of an essentially flexible pressure responsive member urged to one position by a hydraulic pressure impulse, and to the other position by the excess of pump inlet liquid pressure over an attenuated hydraulic impulse. Some excess of valve actuating pressure over pumping impulse pressure is desirable in this case, however, and a separate valving impulse, or a pressure reducing valve arrangement connected to the diaphragm impulse, may be employed for this purpose, or the valve merely located at a lower level than the diaphragm so as to have increased hydraulic pressure head.

With the above in view, it is therefore an object of the present invention to provide a fluid pump which is capable of pumping slurries and suspensions without excessive fouling of the valves.

It is a further object of the invention to provide such a pump wherein valve operation is effected by large and constant actuating forces.

Another object is to provide a pump valve which does not vary the pumping volume of the pump chamber during operation.

A still further object is to provide a fluid pump actuated by hydraulic impulses wherein the fluid passages are large in cross sectional area.

These and other objects of the invention we achieve by the means disclosed in the following detailed description of illustrative examples of preferred forms thereof, taken in conjunction with the drawings, wherein:

FIG. 1 is a sectional view of a fluid displacement pump having a pressure-responsive valve constructed in accordance with the present invention, and utilizing a diaphragm as the pressure responsive means;

FIG. 2 is a sectional view of an alternative construction for an inlet valve, utilizing a bellows as the pressure responsive means;

FIG. 3 is a sectional view of an alternative construction, utilizing a piston-operated valve and diaphragm;

FIG. 4 is a sectional view of an alternative construction for an outlet valve of FIG. 1;

FIG. 5 is a sectional view of an alternative construction of an inlet valve for FIG. 1; and

FIG. 6 is a sectional view of an alternative construction for an inlet valve applicable to FIG. 1.

There is seen in FIG. 1 a rigid casing comprising cheeks 12 and 13 and a block 14 fastened therebetween by bolts such as 15, which also hold in place a pair of diaphragms 16 and 17 made of flexible material such as polytetrafluoroethylene and communicating on their outer sides by means of the drilled passageway 28 and the fitting 19 with a source of diaphragm activating hydraulic impulses not shown. A diaphragm return spring 21 operates on check pieces such as 22 in contact with the diaphragms to expand them and produce an evacuated space therebetween constituting a pumping chamber 11 for the pump suction stroke, upon hydraulic impulse relaxation. While the spring 21 as shown is in this pumping chamber 11, it will be understood that a pair of springs can equally well be substituted on the other side of diaphragms 16, 17, to pull them towards the cheeks 12, 13 and so produce the pumping chamber 11 therebetween.

A valve 23, in accordance with the invention, at the pump inlet, although shown in the closed position in FIG. 1', is normally held in the open position by the spring 24 urging it downwardly, so that the pump inlet 25 is in communication with the pumping chamber inlet 26. By reason of the fact, however, that the valve chamber 27 communicates through the drilled passage 28 with the pressure chamber 10 on the outer side of diaphragm 17, hydraulic impulses there are communicated via passage 28 and are applied to the underside of the valve diaphragm 31 to lift valve 23 into contact with the valve seat 29, and thus close the pump inlet upon the first arrival of a hydraulic impulse.

An outlet valve 32 is of conventional construction and seals the pump outlet 33 in the head plate 35, which is secured by screws 36 and gasket 37 to the pump body, against backflow, by pressure of the valve spring 34 against said valve 32.

In FIG. 2, there is shown a modified version of the inlet valve for FIG. 1 wherein the valve 23 is compressed against its valve seat 29 by expansion of a corrugated metal bellows 41 communicating with an opening 42 to which hydraulic pressure impulses may be applied from the hydraulic chamber in the same manner as in FIG. 1, or from a separate source of such impulses, not shown. Upon receipt of such impulses, the bellows 41 expands upward and forces the inlet valve 23 closed. The base of the bellows is shown in broken section, to indicate the manner in which the bellows assembly may be retained in a counterbore of the opening 42 by a press fit, if convenient, or by proper design the assembly may of course be threaded or retained in place by any of a variety of well known means.

FIG. 3 shows a modified form of inlet valve applicable to FIG. 1 wherein the valve 51 is joined to a diaphragm 55 by means of screw member 52. Said diaphragm 55 is in fixed relation between cheeks 12a and. 13a and piston block 53 which accommodates piston 56. The block 53 is provided with a passage 58, opening into valve chamber 57. Beneath the block 53 there is provided another diaphragm 55a to seal off the piston chamber 57. The diaphragm is held in fixed, sealing position by means of block 60 and the usual fastening means 54. It is to be noted that the block 60 is provided with an oil pressure opening or inlet 60a. The piston 56 is formed integral with or securely aflixed to valve 51, so that when pressure is applied to diaphragm 55 within the valve cham ber 57 through the passageway 58 (by means not shown but functionally similar to those described in connection with FIG. 1), the diaphragm and valve 51 are caused to move upwardly. Upward motion of valve 51 compresses valve spring 59, and forces valve 51 against seat 61, closing the pump inlet. Upon release of valve chamber. pressure against diaphragm 55, valve 51 is moved downwardly by tension of valve spring 59 to open the pump inlet.

In this form, it will be noted that it is also possible to operate the hydraulic inlet valve solely by means of pressure acting on piston 56 in the cylinder. In this case, the diaphragm 55 can be omitted, and a .properly proportioned piston and cylinder may be used to close the suction or intake valve, communicating passage 58 with the other side of piston head 62. In FIG. 3, piston 56 moves intake valve 51 to close it responsive to pressure on flexible diaphragm 55, which also acts as a liquid seal to prevent chemical or slurry being pumped from leaking out of the pump. It is to be noted that the diaphragm is not subjected to any pressure higher than that of the suction inlet of the pump, and is only under atmospheric pressure on the outside.

By means of such an arrangement, pressures in excess of 1000 lbs. per sq. in. may be reached without damage to the intake valve diaphragm, since it would be under no greater pressures or strain than if the pump were operating against a zero head. Furthermore, any oil that leaks past piston 56 would be drained back into the hydraulic system reservoir via drain 58. If however, too great a pressure cannot be supplied to urge the valve 51 against its seat 61, piston 56 may be of such diameter as to apply any mechanical pressure to the inlet valve 51 as desired. This feature is desirable where too great a mechanical pressure will wear the seats away too quickly. The same can be accomplished by use of a diaphragm55a. In this case the diaphragm would act as a piston substitute, having the added advantage that it would be proportioned to deliver the desired seat pressure, to seat the valve.

Furthermore, by merely cutting a hole in diaphragm 55a the valve is then operated by an oil pressure piston. By leaving diaphragm 55a intact the valve is operated by the diaphragm and no oil touches the piston which in this case acts as a push rod acting against spring 59. Upon release of valve chamber pressure, valve 51 and piston 56 are moved downwardly by means of spring 59.

In FIG. 4 there is seen an alternative form of pump outlet valve structure applicable to FIG. 1. It is adapted for fastening by means of the bolts 36 to the pump body of FIG. 1 in place of head plate 35 and its valve 32 and spring 33. A flexible and impervious diaphragm 71 is retained between exit body 72 and head plate 73, having affixed to it the stem 74 of a reverse acting valve 75 which can close on seat 76 in the direction of pumped flow. A

tension spring 77 holds valve 75 normally closed in the absence of hydraulic actuating impulse and is supported in a rod which is packed with packing 79 and retained by nut 81 and lock nut 82 on a threaded portion 83 of rod 78. Pressure impulses in the drilled passageway 30 of FIG. 1 communicate with the passageway 81a of FIG. 4 to depress diaphragm 71 and open outlet valve 75 at an appropriate phase of the pumping cycle, secured by properly designing the area of diaphragm 71 in relation to that of seat 76 according to well known principles, so that outlet valve 75 opens only after pumping chamber pressure exceeds pump head pressure.

In FIG. 5, there is seen an alternative inlet valve assembly to be employed in place of valve 23 of FIG. 1 by placing its outlet pipe 91 in communication with the inlet channel 25 of FIG. 1. A relatively impermeable outer casing 92 surrounds and is sealed to the valve inlet pipe 93 and the outlet pipe 91 with the valve member 94 sealed therebetween. Valve actuating pressure impulses from pressure chamber are provided by means not shown through the line 95 of the interior of casing 92, and thus to the exterior of valve member 94. Said member is constructed of readily collapsible impermeable material, and thus collapses to seal off the flow through pipes 91 and 93 when the exterior pressure thereon exceeds the absolute pressure in said pipes. It is necessary to establish a differential in pressure between the pump actuating impulses in pressure chamber 10 and the hydraulic impulses actuatingthe instant valve, in order to ensure closing of the valve before increase in pressure in pumping chamber occurs, so that back flow will not take place in the instant inlet valve. This may be accomplished by using a separate but synchronously timed and phase displaced pressure impulse separately generated in a duplicate impulse generator of'known type, or more simply when a hydraulic impulse fluid of substantial specific gravity is employed by merely lowering the inlet valve some distance in respect to the location of the pumping chamber 11, as by employing it in the place of a conventional foot valve.

In FIG. 6, there is seen an alternative construction of a valve suitable for application to the bottom portion of FIG. 1, replacing the valve there shown. The instant embodiment is contemplated as an inlet valve, however, having a fluid inlet channel 101 in the block 107 communicating with the pump chamber of housing 12 and .13 of FIG. 1 to which it is attached by screws 36. An upper block 102, recessed for the retention of a compression type of valve return spring 103, is seen to retain the periphery of diaphragm 71 by pressure against block 104. Block 104 has a channel 105 communicating with its interior cavity beneath diaphragm 71 for applying hydraulic pressure pulses thereto from chamber 10, to lift the valve stem 74, which slides therein in a boss containing an O ring seal 106 for hydraulic fluid retention, because of its attachment to said diaphragm. Valve 75 on the stem 74 is thereby lifted against the valve seat 29, to close the channel 101.

It is to be noted that pumping pressure developed in the pumping chamber and acting on the upper face 78. of valve 75 is thereafter effective to force the valve 75 more firmly closed, so that a self-locking effect is produced which is effective to assist in the prevention of valve leakage, even in the case of reduced intensity of the valve actuating hydraulic impulses.

Although this invention has been described in terms of a specific illustrative example of the best means known to the inventors of practising the same, it will be apparent that there will occur to those skilled in the art certain elaborations and modifications which do not, however, depart from the essential spirit of the invention disclosed, and it is therefore intended that the invention shall be limited only by the appended claims,

We claim:

1. A pump for supplying liquid to a line comprising,

in combination, a pump chamber, a pressure chamber,

and a diaphragm therebet-ween; bias means, in one of said chambers, operatively connected to the diaphragm and normally retaining the diaphragm in a first position; liquid connections to the pumping chamberfor flow of liquid to and from the chamber, and a liquid connection to the pressure chamber for flow of pressure liquid to the chamber to pulse the diaphragm against the action of the bias means, the bias means acting to restore the diaphragm to the first position upon reduction of liquid pressure in the pressure chamber; a valve and valve seat disposed across the line of liquid flow through the pump chamber for controlling the flow of liquid therein, the valve being reciprocatingly mounted for movement bet-ween open and closed positions, respectively away from and toward the valve seat; liquid pressure-responsive means operatively attached to the valve, and a liquid connection communicating the pressure responsive means with one of the chambers of the pump for operation of the valve in response to liquid pressure in the said chamber.

2. A diaphragm pump in accordance with claim 1 wherein the valve and valve seat are disposed across the liquid inlet to the pumping chamber.

3. A diaphragm pump in accordance with claim 1 wherein the valve and valve seat are disposed across the liquid outlet from the pumping chamber.

4. A diaphragm pump in accordance with claim 3 wherein a second valve and second valve seat are disposed across the liquid inlet to the pumping cham ber.

5. A diaphragm pump for supplying liquid to a line comprising, in combination, a pump chamber, a pressure chamber, and a diaphragm therebetween; bias means, in one of said chambers, operatively connected to the diaphragm and normally retaining the diaphragm in a first position; liquid connections to the pumping chamber for flow of liquid to and from the chamber, and a liquid connect-ion to the pressure chamber for flow of pressure liquid to the chamber to pulse the diaphragm against the action of the bias means, the bias means acting to restore the diaphragm to the first position upon reduction of liquid pressure in the chamber; a valve and valve seat disposed across the line of liquid flow through the pump chamber for controlling the flow of liquid therein, the valve being reciprocatingly mounted for movement between open and closed positions, respectively away from and toward the valve seat; bias means normally retaining the valve in one of said positions; liquid pressure-responsive means operatively attached to the valve, and a liquid connection communicating the liquid pressure responsive means with one of the chambers of the pump for operation of the valve in response to liquid pressure in the said chamber, and against the action of the bias means.

6. A diaphragm pump in accordance with claim wherein the liquid pressure-responsive means comprises a second diaphragm.

7. A diaphragm pump in accordance with claim 6 wherein the second diaphragm is of a resilient material.

8. A diaphragm pump in accordance with claim 6 wherein the second diaphragm is in the form of a \be'llows.

9. A diaphragm pump in accordance with claim 6 wherein the second diaphragm is in the form of a sheet.

10. A diaphragm pump in accordance with claim 6 wherein the second diaphragm and bias means are combined and comprise a Belleville spring.

11. A diaphragm pump in accordance with claim 6 wherein the second diaphragm is attached to a piston.

12. A diaphragm pump in accordance with claim 5 wherein the liquid pressure-responsive means comprises a piston reciprocatingly mounted in a cylinder.

13. In a pump for metering the flow of fluid in a line of a kind in which a pumping chamber for the fluid has inlet and outlet valves connected thereto and has a contractile wall section which is caused to dilate and contract alternately due to the application of hydraulic pressure impulses which have an accurate-1y maintained volume, to the side of the wall section which is remote from the pumped fluid, by means of a pressure chamber enclosing the wall section and communicating with a source of hydraulic pressure impulses, the improvement which comprises: valve means for regulating the flow of fluid located in the line of flow through the pumping chamher and comprising a valving chamber for the pumped fluid,'a movable wall portion defining a part of said valving chamber and movable to occlude the line of fluid flow therethrough by movement of its inner side, valve pressure chamber means enclosing the outer side of said valve means movable wall portion and being in hydraulic communication with the source of hydraulic pressure impulses and pumping chamber wall section return means located within the pumping chamber andcomprising resilient means having a restoring force sufiicient to cause pump diastole between the hydraulic pressure impulses while maintaining a positive hydraulic pressure at the source of pressure impulses.

14. The invention set forth in claim 13, wherein said valve means comprises an inlet valve.

15. The invention set forth in claim 13, wherein said valve means comprises an inlet valve and an outlet valve.

16. The invention set forth in claim 13 wherein there is a resilient return member located within the valving chamber, in connection with said movable wall portion thereof, and having resiliency such as to cause valve operation only upon application of a predetermined hydraulic impulse pressure to said valve means movable wall portion.

17. The invention set forth in claim 13 wherein there is a resilient return member located outside the valving chamber, in connection with said movable wall portion thereof, and having a resiliency such as to cause valve operation only upon application of a predetermined hydraulic impulse pressure to said valve means movable wall portion.

18. The invention set forth in claim 14 wherein said valving chamber movable wall portion comprises. a diaphram.

19. The invention set forth in claim 14 wherein said valving chamber movable wall portion comprises a Ibellows.

20. The invention set forth in claim 14 wherein said valving chamber movable wall portion comprises a piston.

References Cited by the Examiner UNITED STATES PATENTS 862,867 8/1907 Eggleston 230- 1,627,257 5/=1927 Stevens 10344 2,529,028 11/1950 Landon 103-44 2,843,050 7/ 1958 Harper 103152 2,919,650 1/1960' Wiggermann 103-44 3,007,416 11/1961 Childs 103-44 ROBERT M. WALKER, Primary Examiner.

DONLEY J. STOCKING, Examiner.

Claims (1)

1. A PUMP FOR SUPPLYING LIQUID TO A LINE COMPRISING, IN COMBINATION, A PUMP CHAMBER, A PRESSURE CHAMBER, AND A DIAPHRAGM THEREBETWEEN; BIAS MEANS, IN ONE OF SAID CHAMBERS, OPERATIVELY CONNECTED TO THE DIAPHRAGM AND NORMALLY RETAINING THE DIAPHRAGM IN A FIRST POSITION; LIQUID CONNECTIONS TO THE PUMPING CHAMBER FOR FLOW OF LIQUID TO AND FROM THE CHAMBER, AND A LIQUID CONNECTION TO THE PRESSURE CHAMBER FOR FLOW OF PRESSURE LIQUID TO THE CHAMBER TO PULSE THE DIAPHRAGM AGAINST THE ACTION OF THE BIAS MEANS, THE BIAS MEANS ACTING TO RESORE THE DIAPHRAGM TO THE FIRST POSITION UPON REDUCTION OF LIQUID PRESSURE IN THE PRESSURE CHAMBER; A VALVE AND VALVE SEAT DISPOSED ACROSS THE LINE OF LIQUID FLOW THROUGH THE PUMP CHAMBER FOR CONTROLLING THE FLOW OF LIQUID THEREIN, THE VALVE BEING RECIPROCATINGLY MOUNTED FOR MOVEMENT BETWEEN OPEN AND CLOSED POSITIONS, RESPECTIVELY AWAY FROM AND TOWARD THE VALVE SEAT; LIQUID PRESSURE-RESPONSIVE MEANS OPERATIVELY ATTACHED TO THE VALVE, AND A LIQUID CONNECTION COMMUNICATING THE PRESSURE RESPONSIVE MEANS WITH ONE OF THE CHAMBERS OF THE PUMP FOR OPERATION OF THE VALVE IN RESPONSE TO LIQUID PRESSURE IN THE SAID CHAMBER.

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