US3386388A

US3386388A - Hydraulically actuated pump

Info

Publication number: US3386388A
Application number: US559547A
Authority: US
Inventors: Rosenberg David
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-06-22
Filing date: 1966-06-22
Publication date: 1968-06-04
Anticipated expiration: 1985-06-04

Description

June 4, 1968 D. Rosr-:NBERG 3,386,388

HYDRAUL I CALLY ACTUATED PUMP Filed June 22, 1966 United States Patent O 3,386,388 HYDRAULICALLY ACTUATED PUMP David Rosenberg, 12 Francis Court, Glen Cove, N.Y. 11542 Filed June 22, 1966, Ser. No. 559,547 14 Claims. (Cl. 103--152) ABSTRACT F THE DISCLOSURE A hydraulically actuated diaphragm pump is provided having a check valve in a line from the hydraulic source to the chamber adjacent the diaphragm. A second hydraulic line connects the pump valve with the hydraulic source. The check valve creates a differential pressure between the chamber and the second hydraulic line on a stroke of the pump to maintain the sequence of movement between the diaphragm and the pump valve.

This invention relates to fluid devices, and more particularly to uid displacement pumps of the type adapted to iluid actuation.

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 ilow of hydraulic uid 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 iluid impulses.

The pumping mechanism itself is frequently a diaphragm pump actuated by the pumping impulses, and provided with inlet and outlet valves for the control of the iiow 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 rnaterial. 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, coagulating and building up 0n 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 eifectiveness. Similar deposits can also build up on the outlet valve.

Even in cases where such extreme consequences do not occur, many of these suspensions, such as those of talc, chalk or fullers earth, or 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 diiculty 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 as- Patented .lune 4, 1968 ICB sume differ-ent positions according to the pressure exerted upon it. Minimizing the size of the valve thus reduces but cannot eliminate the changes in pumping chamber volume arising from this cause, and accentuates all of the aforementioned diiculties due to suspended material in the pumped iluid, both because of the diiculty of constructing such a small part with precision, and because of increased ow velocity and consequent erosion which such small size requires.

Slurry pumps are known which overcome many of these ditiiculties by providing pressure-actuated valves which are of relatively large dimensions, and are driven between open and closed positions according to the fluid pressure impulse applied in a separate hydraulic system, which is also in fluid pressure connection with the hydraulic cham-ber of the pump to actuate the pump. Such pumps are shown in U.S. application Ser. No. 396,794, led on Sept. 4, 1964, now U.S. Patent No. 3,256,825.

Pressure-actuated valves can be formed of a size suiiicient to ensure accurate and reliable operation in pumping slurries, and to reduce the flow through the valve to the point where `excessive deposition of slurried particles does not occur. Moreover, it is possible to form the valves and seats of a hard material which is highly resistant to abrasion and which can be 'formed with sufficiently sharp edges to cut through any deposits which may form, thereby having a self-cleaning action.

An even greater degree of accuracy has been obtained by having one of the valves hydraulically actuated and biased (such as by a spring) against the actuating hydraulic pressure to keep the valves open or closed, as desired. Generally, the pump inlet valves are biased open, and the outlet valves are biased closed. Biasing is especially important when pumping highly concentrated, a-brasive slurries. However, the accuracy of the pump can be seriously impaired if the other valve is operated directly by the pumped slurry. Particles more readily are deposited in the valve, preventing the valve from fully closing, when the operation of the valve is dependent upon the pressure exerted against the upstream face of the valve by the pu-mped slurry.

When both valves are operated by a separate hydraulic system, the problems of clogging and sticking of the valves are substantially eliminated, even when pumping highly concentrated abrasive slurries. However, other problems are encountered when Iboth the inlet and the outlet valves, as well as the pumping member, are biased and hydraulically activated. All of the bias members have to be very precisely calibrated so that the valves and the pump are actuated by the same hydraulic pressure at the same time, i.e. the inlet valve open or close, the outlet valve close or open and the pumping member expand or contract, respectively, at the same hydraulic pressure in the hydraulic pressure system at the same time. The problems of maintaining such exact response in commercial operations are overwhelming. Furthermore, the bias means, such as springs, normally do not all wear at the same rate, and inaccuracies soon develop during operation, requiring constant adjustment of the pump settings.

It has now been found, however, that hydraulicallyactuated, biased inlet and outlet valves can be used together in a hydraulically-actuated pump with only approximately calibrated bias means, wherein the exact force exerted -by each of the bias means is not critical to the accuracy of the pump. Furthermore, according to this invention, the valves and pumping member can -be actuated in any desired order.

The bias members are preferably calibrated so that on the compression stroke of the pump a relatively low hydraulic pressure actuates the inlet valve to close, the

same or a relatively higher hydraulic pressure actuates the outlet valve to open and a still higher hydraulic pressure, the highest of the three, actuates the pumping member. According to this invention, means are also provided such that during the intake stroke of the pump the outlet valve closes first, at the relatively highest hydraulic pressure, the inlet valve opens simultaneously or subsequently at the same or at a relatively lower hydraulic pressure, and the pumping member is actuated last at the relatively lowest hydraulic pressure. ri`he term effective hydraulic pressure as used herein refers to the pressure differential across the pressure-responsive member in question, such as a diaphragm or piston eX- posed on one side to hydraulic system pressure and on the other side to pump system pressure.

The invention accordingly provides a pump for supplying fluid through a line compising, in combination, a pump chamber; a pressure chamber; and a diaphragm therebetween normally biased towards a rst position; a fiuid connection through the pump chamber for flow of fluid to and from the chamber; a fiuid pressure-responsive valve having open and closed positions and disposed across the line of fiuid flow through the pump chamber for controlling the iiow of iiuid therein, said valve ybeing normally biased towards one of the open and closed positions; a hydraulic system comprising a source of hydraulic pressure; a first hydraulic fiuid connection to the pressure chamber for fiow of pressure fluid to the pressure chamber for movement of the diaphragm away from the first position to pump iiuid through the pump chamber and the `fluid connection therethrough; a second hydraulic fluid connection communicating the fiuid pressure-responsive valve with one of the pressure and pump chambers of the pump for movement of the valve away from its first position to the other of its positions in response to tiuid pressure in the chamber; the valve and the diaphragm being moved in a predetermined sequence by predetermined hydraulic pressures developed by the hydraulic source in the second hydraulic fiuid connection and in the pressure chamber, respectively; and regulating means in said first hydraulic fiuid connection producing on alternate strokes of the pump a pressure difference between the pressure chamber and the second hydraulic fiuid connection greater than the difference between the effective bias strength acting on the valve and the effective bias strength acting on the diaphragm, thereby maintaining the sequence of movement of the valve and the diaphragm upon each successive stroke of the pump.

The term stroke is intended to describe a complete movement of the diaphragm in a single direction between its extreme positions, i.e. the intake stroke and the exhaust stroke.

Preferably, the regulating means comprises check valve means in the first hydraulic fluid connection, bias means operatively connected to said check valve means in a manner permitting the valve to open to flow in one direction at a substantially zero pressure drop across the valve and permitting the valve to open to fiow in the other direction only at a predetermined pressure drop across the valve, the effective strength of the bias means acting upon the check valve being greater than the difference between the effective bias strength on the diaphragm and the effective bias strength on the Valve.

Thus, on the pressure stroke, upon increase in hydraulic fluid pressure in the hydraulic system, the increased pressure is communicated to the pressure-responsive valve which is actuated to its second position, i.e. the inlet valve to a closed position or the outlet valve to an open position, and then actuates the diaphragm. lf the valve is an inlet valve, the lbias means acts to hold it open, and the valve is driven to a closed position upon increase in pressure in the pressure chamber. lf the valve is an outlet valve, the bias means acts to hold it closed, and it is driven to an open position, upon increase in pressure in the pressure chamber. On the intake stroke, when the hydraulic pressure is relaxed, the valve is first moved back to its first position, i.e. the outlet valve is first closed or the inlet valve first opened, and then the diaphragm moves to draw in uid to the pump chamber.

Preferably, the inlet and outlet valves are hydraulically actuated and biased. The bias means acting on the diaphragm as well as those acting on both valves can be so set that they are actuated at the same pressure in the hydraulic system provided by the pulse means. In the preferred embodiment, where both valves are hydraulically actuated and biased, both valves are preferably actuated before the diaphragm on both strokes, and the inlet valve is preferably actuated at a lower hydraulic pressure than the outlet valve, for greatest accuracy of operation. As used hereafter, the effective strength of the bias means and the effective bias strength refers to the effective hydraulic pressure required to overcome the `bias means.

The regulating biased check valve means can include a single double-seating valve or a pair of check valves, one 4being free `to open to fiow in one direction, i.e., unbiased, and the other being biased against opening to flow in the other direction, located in parallel hydrau'ic fiuid connections between the hydraulic pressure source and the pressure chamber of the pump.

The direction in which the biased check valves operate depends upon the relative effective strength exerted by each of the bias means acting on the diaphragm and on the valve. If the bias member on the diaphragm has the greatest effective strength, the check valve of zero pressure is opened when a positive pulse of hydraulic pressure is applied on the pressure stroke of .the pump, i.e. when hydraulic fluid flows into the pressure cham-ber of the pump. The biased valve lis opened during the reverse ow, when the hydraulic pulse is relaxed and fluid flows out of the hydraulic chamber. The biased check valve operates only after the difference between the hydraulic pressure in the rest of the hydraulic system and in the pressure chamber, or the pressure drop across the check valve, is greater than the effective strength of the check valve bias means. If the bias means on the valve is stronger than that on the diaphragm, the check valves act in the reverse direction.

The bias means on the check valve need only be greater than the difference between the effective strengths ot' the valve bias means and the pump bias means. The inlet -or the outlet valve is thereby closed or opened, respectively, prior to the movement of the diaphragm on the pressure stroke and is similarly actuated to be opened or closed respectively prior to the movement of the diaphragm on the intake stroke. This arrangement is suitable when one or both of the inlet and outlet Valves are biased and actuated hydraulically.

Preferably, when both the inlet and the outlet valves and the diaphragm are biased and hydraulically actuated, the inlet valve bias means has the lower effective force. However, if desired, these valve bias means can have substantially equal effective strengths.

The pump Valves as used in this invention generally include a valve body and `a valve seat disposed across the line of fiow through the pump chamber. The valve body is mounted for to and fro movement between open and closed positions away from and in contact with the valve seat. Bias means are connected to the valve body to retain it in either an open or closed position. Fluid pressure-responsive means are attached to the valve body for moving it against the action of `the bias means and the fluid pressure responsive means is in fiuid connection with one of the chambers of the pump, usually the pressure chamber.

Preferably, the source of hydraulic pressure is a pulsing means such as a piston pump having means to supply on each pressure stroke of the piston a known volume of hydraulic fluid to the hydraulic chamber ,to dstend the diaphragm. The preferred pump is an adjustable recipro.

eating piston pump of the type shown in U.S. Patent No. 2,869,467, discussed above. In that pump, on each suction stroke of the piston, the cylinder is vented to a reservoir of oil which in .turn is vented to the atmosphere. Any air or other gas which may collect in the hydraulic chamber of the diaphragm pump is thereby swept out of the cylinder into the reservoir and then to the atmosphere. The fact that the pumping cylinder is immersed in a reservoir of oil prevents any additional air from entering the hydraulic chamber during the venting. Pulsing systems other than reciprocating piston pumps are also suitable for use in the invention, such ras a rotary piston pump. The hydraulic system of these pumps include the hydraulic pressure chamber `of the pump, any conduits connecting that chamber to the pulsing means and valves, and usually, the pulsing means itself.

The pumps of the invention can include a plurality of diaphragms, in the manner, for example, shown in U.S. Patent No. 3,100,451. The pumping chamber or alternatively, the pulsing or hydraulic chamber, can, for example, be in the form of a cylinder, closed at each end by an impermeable flexible diaphragm, with the bias means always in the pulsing or hydraulic chamber or chambers. In the case of a double diaphragm pumping chamber, the tension bias means is placed outside the diaphragms, and the hydraulic liquid is supplied to the hydraulic -chambers outside the diaphragms. In the case of a double diaphragm hydraulic chamber, the tension bias means is placed between the diaphragms and the hydraulic liquid is supplied to the chamber therebetween for flexing action of the diaphragms in the pumping chambers. In such a structure, two different liquids could be pumped, and one diaphragm could be stopped (an adjustable stop can be used) so that the other receives a pressure effect of a proportion of the volume of hydraulic fluid supplied, the total amount of this fluid in turn being adjusted by the effective stroke of the pisto-n. If but one liquid is to be pumped, the Valves can be manifolded so that la single outlet could be used.

The bias means is of the tension or compression type depending upon the position of the hydraulic chamber and the direction of the bias force required. Any form of 4bias means can be used. Coil springs, disk springs, also known as Belleville springs or washers, and resilient bushings or plugs are typical, and various embodiments thereof are shown in the drawings. These can be made of any suitable material, usually metal, such as stainless steel, carbon steel, nickel, brass and bronze, or plastic, such as rubber, synthetic rubber, polyamides, polypropylene, polyvinyl butyral, or metal coated with any inert plastic material.

The diaphragrns employed in the proportioning pumps of the invention can be -made of any sheet material which is suiciently ilexible and resilient to be flexed under uid pressure, and which can be returned to normal nonflexed position when the fluid pressure is relieved, aided, in accordance with the invention, by bias means. Desirably, the diaphragm can withstand many .millions of such exures without damage.

For additional strength, the sheet diaphragm can be provided with a backing material or plate which will prevent damage due to overpressuring, and can also serve to control .the amount of flexure under a given fluid pressure.

In addition, to increase flexibility, a diaphragm can be formed as a composite or multiple ply structure. Two or more exible sheets, of the same or different material, can be laminated or clamped together to form the diaphragm. If the sheets are laminated, they can be joined together with an adhesive material, by welding or any other suitable means. The use of a laminated or clamped structure of very thin sheets increases the strength of a diaphragm of a given resiliency, thereby allowing for a greater ran-ge for exing on each stroke of the diaphragm. The laminate is preferably designed so that the outer plies are strong in tension and the center plies strong in compression. The

laminate can also be formed of materials with directional strength by alternating directions of axes in each ply. In the case of plural diaphragms, the diaphragms can all be laminated, or only one can be laminated, as desired. The laminated diaphragm can be designed -to have the same or a different resiliency than the single ply diaphragm.

The configuration of the diaphragms can be selected according to the pumping requirements. For instance, the diaphragm can be of uniform thickness throughout its area. It can also be designed to be thicker at the center than at the periphery, so as to increase its resistance to flexing. The shape of the diaphragm is quite immaterial and the `diaphragm can be circular, elliptical, polygonal, rectangular, square or indeed any shape, according to the design of the hydraulic or pulsing and pumping chambers. Thus, for example, the diaphragms can be made of sheet metal, such as stainless steel, Monel metal, aluminum, copper, carbon steel, brass, tin, nickel and zinc, or of a resilient plastic sheet material such as ru-bber, synthetic rubber, neoprene, Viton A, urea-formaldehyde, melamineformaldehyde, phenol-formaldehyde, polymethylmethacrylate, nylon, polystyrene, polytetrafluoroethylene, polyt-riuorochloroethylene, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride and polycarbonate resins, and epoxy resins; and fiber-reinforced laminates of any of these materials, erg. glass fiber, cotton fiber, linen fiber and the synthetic fibers such as nylon.

The back-up plates or other materials used, if desired, for reinforcement can be made of the same or different materials. Thus, for instance, a stainless steel diaphragm can -be supported by a stainless steel plate or by a plastic plate, and a rubber diaphragm can be reinforced by a stainless steel plate or by a plate made of polytetrauoroethylene or nylon. These are merely illustrative examples, and other combinations will be apparent to those skilled in the art from the above description.

The pulsing or hydraulic fluid can be selected as desired, according to the bias means employed, and 'will be inert to the bias means, the diaphragm and hydraulic chamber walls. Any hydraulic uid can be used. The hydraulic fluid can, for example, be a lubricating oil or other non-corrosive petroleum liquid, a silicone oil, or a polyalkylene glycol ether.

The pressure-responsive means acting on the valve can take any of several forms. A diaphragm is especially aclvantageous, 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 polyamide, polytetrauoroethylene, polycarbonate, polystyrene, polyethylene, or polypropylene. It can be resilient, such as rubber, or synthetic rubber, or a sheet spring, such as a Belleville spring disc or washer, affixed to a piston-type or poppet valve. Reinforcing support can be provided a ydiaphragm 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 is particularly desirable. A piston can be combined with a diaphragm to increase the surface area open to pressure actuation in one direction and thus permits high hydraulic fluid pressure for actuating the pump diaphragm Without exceeding permissible valve seating pressure and/ or valve diaphragm bursting pressures. Such a valve is shown in application Ser. No. 396,794, led Sept. 4, 1964, now.

U.S. Patent No. 3,256,825,

The bias means for the valve include a tension or compression spring, or appropriate design and resiliency including any of the types set forth above for the diaphragm bias means. The inherent resiliency of the valve actuating member, -such as a stainless steel diaphragm can 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.

The drawings show several preferred embodiments of the invention.

FIGURE l is a sectional View of a tluid displacement pump having pressure-responsive valves constructed in accordance -with the present invention, and utilizing diaphragms as the pressure-responsive means.

FIGURE 2 is a partial sectional view of an alternative form of hydraulic iluid connection bet-Ween the pressure chamber and the pulsing means for FIGURE 1.

Referring to the drawings, the diaphragm pump shown in FIGURES l and 2 includes a pump section 1, a hydraulic section casing 2, a valve section casing 3 and a pulsing means section 4. The

sections

1, 2, 3 and 4 are held together by bolts passing through flanges not shown. Dened within the pumping section 1 are pump chamber 5 and inlet and outlet conduits 7 and 9 to the pump chamber. Also defined within the pump section is a portion of a hydraulic line 10. Defined within the hydraulic section 2 is the hydraulic pressure chamber 12, hydraulic line 10, in alignment with the portion of hydraulic line in the pump section 1, and parallel hydraulic lines 14 and 15 connecting the hydraulic line 10 to the hydraulic pressure chamber 12.

Diaphragm defines one wall of the pumping chamber 5 and one wall of the hydraulic chamber 12. The flexible diaphragm 20 is clamped between the hydraulic casing 2 and the pump casing 1. Bolt 24 passes through a central opening in the diaphragm 20 and is threaded into a hanged nut 22 on the pumping chamber side of the diaphragm. To prevent leakage through the diaphragm, a sealing nut 25 is threaded on -bolt 24 on the hydraulic chamber side of the diaphragm, and nuts 22 and 25 clamp on to the diaphragm 20, to form a leakproof seal. At the far end of bolt 24 is the bolt head 27.

The compression coil spring 29, for biasing the diaphragm, is held between a perforated back-up plate 30, also clamped at its periphery between the pump casing 1 and the hydraulic casing 2, and the spider 32, which is tted between bolt head 27 and sealing nut 25. Two

perforations

31 and 33 in the back-up plate 30 are aligned with hydraulic lines 14 and 15 respectively. Thus, whenever the diaphragm 20 is flexed outwardly into the pumping chamber 5, such movement is against the action of the spring 29, which tends to pull the diaphragm back in the direction of the hydraulic chamber. As a result, when the hydraulic Huid pressure tending to force the diaphragm outwardly is released, the spring 29 pulls the diaphragm 20 back to the normal nonexed position shown in FIG- URE l.

The parallel hydraulic lines 14 and 15 are provided with check valves 35 and 37, respectively. The rst check valve 35 comprises a valve seat 40, Valve ball 41 and compression spring 42 acting as the bias member. The rst check valve 35 prevents any flow through line 14, when positive pressure is applied by the pulsing means through line 10, into the hydraulic chamber 12. In the reverse direction, check valve 35 will permit flow from the hydraulic chamber 12 only after the pressure drop across the valve is sucient to overcome the force of compression spring 42.

The second check valve 37 comprises valve seat 44, ball valve 45 and stop members 46. The second check valve 37 permits flow into the hydraulic chamber 12 when positive pressure is applied by the pulsing means through the hydraulic line 10. The check valve 37 prevents any flow in the reverse direction from the hydraulic chamber when the pressure pulse is released.

The valve section 3 of the pump comprises a top casing Sil, a central casing 5l and a lower casing 52. The top, middle and

bottom casings

50, 5l and 52, respectively, are held together by bolts not shown and any leakage at the joints is prevented by gaskets 59, which can be formed as part of the diaphragm. The middle casing 5l, can be formed in two parts, if desired, to permit changing of the individual valves.

The top casing St) defines an extension of the pump outlet conduit 9, the Valve chamber 55 and valve outlet conduit 57. Valve seat 5S is inserted into the top casing 5t) and defines the upper surface of the valve chamber 5S. The valve diaphragm 61 is clamped between the top and

central casings

50 and 51. The central casing 51 denes the valve hydraulic chambers 64 and hydraulic fluid lines 68, 69 connecting the hydraulic chambers 64 to the main hydraulic fluid line 1) in the pump section 1. Bolt 72 passes through a central opening in the diaphragm 61 and flanged nut 70 in the hydraulic valve chamber 64 is threaded on to the end of bolt 72. To prevent leakage through the diaphragm 61, a sealing nut 74 is threaded on to bolt 72 on the hydraulic side of the diaphragm 6l and

nuts

74 and 73 clamp on to the diaphragm 61 to form a leakproof seal. Perforated plate 75 rests against an outer surface of casing 51 and serves as a stop for the diaphragm 61. The bias spring 63 is mounted between the spider member 76 and the perforated plate 75 to bias the diaphragm in the same manner as by the bias spring 29 for the pump diaphragm 28'.

Bolt Sti is threaded into the top face of the flanged nut 73 and extends upwardly through the valve seat 58. Ball valve 81 is secured to the top of bolt 8G at a position such that it will be held tightly against the valve seat 58 by the force exerted by bias spring 63.

The lower casing 52 of the valve section defines the inlet valve chamber 90, the extension of inlet line 7 connecting to the valve chamber 90. Inlet valve seat 92 is placed into a slot in the bottom valve casing 52.

Diaphragm 62 is clamped between the bottom and

central valve casings

51 and 52. The construction and biasing of the diaphragm 62 in the inlet valve with bias spring 89 is identical to that in the outlet valve described above.

Bolt 95 is threaded into the outer face of ilanged nut 73 and extends towards the valve seat. Ball valve 97 is threaded onto the end of bolt 95 in a position such that when the diaphragm 62 is extended into the inlet valve chamber by a hydraulic pulse in the hydraulic chamber 64, the ball valve 97 will be held securely against the Valve seat 92. As shown the hydraulic valve chambers 64 are separate. However, in an alternative embodiment, the two chambers can be joined as one without any loss in etfectiveness.

The hydraulic line 10 can be attached to any hydraulic pulsing means which will provide periodic hydraulic pulses of a delinite volume. Preferably, however, the pulsing means is a piston-operated hydraulic pump such as that described in U.S. Patent No. 2,869,467, particularly FIGURE 8 thereof. The pulsing means will preferably have adjusting means which will set the volume of the hydraulic pulse transmitted to the hydraulic chamber of the pump and the valves so as to regulate the volume of material swept by the diaphragm 20 of the pump.

In the particular embodiment shown in FIGURE l, the spring 29 of the pump has the greatest effective strength, equal to approximately 3() p.s.i. pressure drop across the diaphragm, for example. The spring 63 of the outlet valve has the next highest effective strength, equal to, for example, about 25 p.s.i. pressure drop across the diaphragm 6l, and the spring 89 of the inlet valve has the lowest effective strength, equal to about 20 p.s.i. pressure drop across the diaphragm 62. The effective strength of spring 42 in check valve 35' is greater than the difference between the effective strengths of the spring 29 and spring 89, approximately 12 p.s.i., in this example. The exact strength of each bias means is not critical, as long as the relationship between them remains the same.

ln operation, the hydraulic pulsing means is adjusted to periodically supply a predetermined volume of hydraulic fluid, in this case oil, through the line 10 and line 15 to the hydraulic chamber 12 and to the outlet and inlet valve hydraulic chambers 64 through lines 68 and 69 respectively.

When a positive hydraulic pulse is exerted by the pulsing means, fluid flows through line 10 and through line 15 into the hydraulic chamber and through lines 68 into the valve hydraulic chambers 64. As the pressure begins to increase in each of the hydraulic chambers, the first bias means is overcome, the inlet valve bias means 89, and the inlet valve diaphragm 62 is pushed outwardly into the inlet valve chamber 90 forcing ball valve 97 to seat firmly against valve seat 92. This closes the inlet to the pump and prevents fluid from passing into or out of the pump chamber through line 7. As the pressure increases in the hydraulic system of the pump, the next bias means is overcome, spring 63 of the outlet valve, and diaphragm 51 is forced outwardly into the outlet valve chamber 55 unseating ball valve 81 from valve seat 58 and opening the outlet from the pump so as to permit fluid flow from the pump chamber 5 through the outlet line 9. Finally, the pump bias means 29 is overcome and the diaphragm 53 flexed outwardly into the pumping chamber 5 and fluid is pushed out.

On the negative stroke of the hydraulic pulsing means, when the hydraulic pressure is being reduced, fluid flows outwardly from the hydraulic chambers through line 10, leaving the valve hydraulic chambers 64 and pump hydraulic chamber 12 through

lines

68, 69 and 14, respectively. Fluid cannot flow outwardly from the hydraulic chamber 12 of the pump until the pressure difference across valve 35 is greater than the effective strength of spring 42, i.e in this case about 12 p.s.i. Accordingly, the pressure in the pump hydraulic chamber 12 is not reduced until the valve 35 is open. As the pressure is decreased in the hydraulic system, the first valve to be actuated is the outlet valve 81 which seats against valve seat 5S as soon as the hydraulic pressure drops below the effective strength of its bias member 63. As the pressure continues t-o drop, the hydraulic pressure against the inlet valve diaphragm 63 is relaxed until it is less than the effective strength of spring 89. The bias spring then moves the valve 97 away from seat 92, opening the inlet valve. When the pressure drop across valve 35 is greater than 12 p.s.i., the valve opens permitting fluid to leave the hydraulic chamber 12. When the hydraulic pressure acting against diaphragm 20 is less than the effective strength of the bias means 29, the diaphragm 20 moves back to its first position, drawing in pump fluid through inlet line 7. The perforated plate 30 acts as a stop to prevent further movement of the diaphragm beyond the limiting position, if necessary.

As the diaphragm 20 moves back from its flex position, upon reduction of pressure in the hydraulic chamber 12, fluid enters the pumping chamber 5 until the fluid in the chamber equals the volume of the chamber.

By adjustment of the volume of fluid delivered to line and of the pulsing period of the hydraulic pulsing means, it will be apparent that any desired volume of fluid from the pumping chamber can be assured.

The inlet and outlet valves of FIGURE 1 can be readily replaced by other types of hydraulically actuated valves. One of the valves can be actuated by the fluid flow through the pump. Examples of various types of valves are set forth in U.S. application Ser. No. 396,794, filed Sept. 4, 1964 now U.S. Patent No. 3,256,825 issued on June 2l, 1966.

FIGURE 2 shows the portion of the pump of FIGURE l outlined by the broken line wherein the two parallel hydraulic conduits 14 and 15 are replaced by the single conduit 16 containing check valve 100. Check valve 100 comprises ball valve 102 which can move between stops 103 and the sliding annular orifice member 104. The sliding annular orifice member permits flow through its central opening but will not permit flow around its outer edges when it is pushed up against valve seat by the compression spring 107. The remaining portion of the pump can be identical to that shown for FIGURE 1.

In operation, when the hydraulic pulse pressure is increasing, the ball 102 is pushed forward against stop 103 permitting flow to pass through line 16. On the reverse stroke of the hydraulic pulse when the hydraulic fluid is flowing out of the pump chamber the ball is pushed against sliding orifice plate 104 plugging the orifice and preventing flow therethrough. As the pressure drop across the valve increases to a point sufficient to overcome the effective strength of the compression spring 107, the annular plate 104 slides backwardly along the line 16 away from valve seat 105 permitting flow to pass through line 16. Accordingly, the same result is obtained with the single passage as was obtained by the pair of parallel conduits of FIGURE 1 with check valves 35 and 37.

When the present invention is utilized with diaphragm pumps having more than one diaphragm, and more than one pressure chamber such as the pump set forth in U.S. Patent No. 3,100,451, the check valve of this invention can be installed upstream of both hydraulic pressure chambers. In this case, one set of check valves will be lo'cated between both hydraulic pressure chambers and the hydraulic pulsing means. Alternatively, two sets of check valves can be used, one in the hydraulic connection to each hydraulic pressure chamber.

Similarly, several different pumps can be operated by a single hydraulic system. Each pump can have a separate diaphragm and a separate hydraulic pressure chamber attached to the same source of hydraulic pressure, or alternatively, several different diaphragms, one for each of several different pumping chambers, can form the walls of the same pressure chamber. The regulating means in either of such pumps can be located in the conduit immediately downstream of the pressure source, or where different pressure chambers are involved regulating means can be installed immediately upstearm of some or all of the pressure chambers.

Having regard to the foregoing disclosure, the following is claimed as the inventive and patentable embodiments thereof.

1. A pump for supplying fluid through a line comprising, in combination, a pump chamber; a pressure chamber; and a diaphragm therebetween normally biased towards a first position; a fluid connection through the pump chamber for flow of fluid to and from the chamber; a fluid pressure-responsive valve having open and closed positions and disposed across the line of fluid flow through the pump chamber for controlling the flow of fluid therein; said valve being normally biased towards one of the open and closed positions; a first hydraulic fluid line for connecting a source of hydraulic pressure and said pressure chamber for communication of source pressure to said pressure chamber for movement of said diaphragm away from said rst position to pump fluid through said pump chamber and said fluid connection therethrough; valve means positioned in said first hydraulic fluid line such that flow of fluid to and from said pressure chamber proceeds via said valve means; a second hydraulic fluid line bypassing said valve means for connecting said source of hydraulic pressure and said fluid pressure responsive valve for communication of source pressure to said fluid pressure responsive valve for source pressure responsive movement of said fluid pressure repsonsive valve between its respective positions; the fluid pressure responsive valve and the diaphragm being moved in a pre-determined sequence by pre-determined hydraulic pressure developed by said source in said second hydraulic fluid line and in said pressure chamber, respectively; said valve means permitting free flow of fluid into said pressure chamber but permitting flow of fluid out of said pressure chamber only upon a pre-determined pressure differential across said valve means, producing on alternate strokes of the pump a pressure difference between the pressure chamber and assasss the second hydraulic fluid line greater than the difference between the effective bias strength acting on the valve and the effective bias strength acting on the diaphragm, thereby maintaining the sequence f movement of the valve and the diaphragm upon each successive stroke of the pump.

2. A diaphragm pump in accordance with claim 1 wherein the valve means comprises check valve means in the first hydraulic fluid line, bias means operatively connected to said check valve means in a manner permitting the valve to open to flow in one direction at a substantially zero pressure drop across the valve and permitting the valve to open to flow in the other direction only at a predetermined pressure drop across the valve, the effective strength of the bias means acting upon the check valve being greater than the difference between the effective bias strength on the diaphragm and the effective bias strength on the valve.

3. A pump in accordance with claim 1 wherein the fluid pressure responsive valve is disposed across the fluid inlet to the pumping chamber.

4. A pump in accordance with claim l wherein the fluid pressure responsive valve is disposed across the fluid outlet from the pumping chamber.

5. A pump in accordance with claim 4 wherein a second fluid pressure-responsive valve is disposed across the fluid inlet to the pump chamber for controlling the flow of fluid thereto, the valve having open and closed positions and being normally biased towards one of the open and closed positions, this valve also being connected to said source of hydraulic pressure for movement of said second fluid pressure responsive valve in response to source pressure.

6. A pump in accordance with claim 5 wherein the effective bias strength acting on the diaphragm is greater than the effective bias strength acting on the outlet valve which is in turn greater than the effective bias strength acting on the inlet valve and wherein the pressure difference between the pressure chamber and the second hydraulic fluid line is greater than the difference between the effective bias strength acting on the pump diaphragm and the effective bias strength acting on the inlet valve.

7. A pump in accordance with claim 5 wherein the effective bias strength acting on the diaphragm is greater than acting on either valve and wherein the pressure difference between the pressure chamber and the second hydraulic fluid line is greater than the difference between the effective bias strength acting on the pump diaphragm and the effective bias strength acting on the outlet valve.

S. A pump in accordance with claim l wherein the rst hydraulic fluid line comprises two parallel fluid conduits, the conduits each having a check valve, one check valve preventing flow in a first direction, the second check valve preventing flow in the other direction, the first conduit having a check valve unbiased to open at substantially zero pressure in one direction and the other conduit having a check valve biased to prevent flow of fluid therethrough in the other direction until a predetermined pressure drop is produced across the check valve.

9. A pump in accordance with claim 1 wherein the first hydraulic fluid line comprises a single fluid conduit including a double-acting valve set to open in a first direction to fluid flow at substantially zero pressure drop and biased in the other direction, to prevent the valve from opening until a predetermined pressure drop is produced across the double-acting valve.

10. A pump in accordance with claim 1 wherein the pressure-responsive valve includes a diaphragm.

i2 il. A pump in accordance with claim 1 wherein the pressure responsive valve includes a bellows.

12. A pump in accordance with claim l wherein the pressure-responsive valve and bias means are combined 5 and comprise a resilient Belleville spring.

13. A pump in accordance with claim 1 wherein the pressure responsive valve includes a piston reciprocatingly mounted in a cylinder.

14. A pump for suppling fluid through a line comprising, in combination, a pump chamber, a pressure chamber and a diaphragm therebetween; first bias means operatively connected to the diaphragm and normally retaining the diaphragm in a first position; a first fluid connection through the pump chamber for flow of a fluid to and from the chamber; an inlet Valve and valve seat and an outlet valve and valve seat disposed across the line of fluid flow through the pump chamber for controlling the flow of fluid therethrough, the inlet and outlet valves being mounted for to and fro movement between open and closed positions, respectively, away from and toward the valve seat; valve bias means operatively connected to each of said valves and normally retaining said valves in a first position, the inlet valve in an open position and the outlet valve in a closed position; fluid pressure-responsive means operatively connected to each of the valves; and a hydraulic system comprising hydraulic pulse means; a first hydraulic fluid connection between the pulse means and the pressure chamber for flow of pressure fluid to the pressure chamber for movement of the diaphragm away from the first position to pump fluid through the pump chamber; a second hydraulic fluid connection communieating the fluid pressure-responsive means with the pulse means for movement of the inlet and outlet Valves away from their first position to their other position in response to fluid pressure in the hydraulic system, the valves and the diaphragm being moved in a predetermined sequence by predetermined hydraulic pressure developed by the pulse means in the second hydraulic fluid connection and in the pressure chamber, respectively; and regulating means in said first hydraulic fluid connection for maintaining the order of actuation of the valves and the diaphragm by hydraulic pressure during successive strokes of the pump comprising check valve means in the first hydraulic fluid connection, bias means operatively connected to said check valve means in a manner permitting the valve to open to flow in one direction at a substantially zero pressure drop across the valve and permitting the valve to open to flow in the other direction only at a predetermined pressure drop across the valve, the effective strength 0f the bias means acting upon the check valve being greater than the difference between the effective bias strength on the diaphragm and the effective bias strength on the valves.

References Cited ROBERT A. OLEARY, Examiner.

W. I. KRAUSS, Assistant Examiner.