Abstract: A technique for pumping an output fluid, especially a particle-laden abrasive liquid. This technique utilizes an output pump and a drive pump which are interconnected through a common chamber containing a drive fluid, specifically water. The output pump includes an output piston within its own pumping chamber for pumping the output liquid by causing the output piston to move through a complete forward stroke. The drive pump includes a drive piston within its own chamber and means for causing the output piston to move the drive piston through its own complete forward stroke. This pressurizes the drive fluid within the common chamber in a way which causes the output piston to move in the forward direction of its stroke. The two pumps are configured such that the forward stroke of the drive piston defines a greater swept volume than the forward stroke of the output piston, thereby to ensure that the output piston will always move through its entire forward stroke before the drive piston.

Abstract: Disclosed herein is a hydraulic to pneumatic power transfer unit which converts a high pressure oil flow into a flow of high pressure air by means of three stages of piston pumps and characterized by a first stage having a pair of linked pistons of substantially equal size both supplying air to a second stage piston which is directly linked to a third stage piston so that the pair of second and third stage pistons work alternately with the pair of first stage pistons and the linkage between each pair of pistons actuate spool valves which control the motion of the other pair of pistons.A further improvement is also disclosed in which an internal oil reservoir and a swash-plate pump is added to the system so that it may be powered by a rotating shaft instead of a flow of oil. In addition, the pulses of oil produced by the swash-plate pump directly control the piston pairs without the need for spool valves.

Abstract: A downhole well pump system comprises a reciprocating piston pump disposed in a fluid conduit in a wellbore which is filled with a driving fluid having a density preferably greater than the production fluid being pumped. The pump cylinder has a transverse partition and a piston assembly including an elongated piston rod extending through the partition and connected at its opposite ends to spaced apart pistons. The pump pistons and the cylinder partition divide the cylinder into a production fluid intake chamber, a production fluid transfer and delivery chamber, a driving fluid chamber and a second production fluid delivery chamber. Production fluid is conducted to the surface through a production fluid conduit disposed coaxial within the driving fluid conduit.

Abstract: In a hydraulic double-acting hydropneumatic pressure multiplying device suited for generating hydraulic pressure, and comprising a cylinder within which a piston is slidably mounted. The multiplying device is capable of generating hydraulic pressure in both the backward and forward strokes of the piston within the cylinder. For this purpose, the cylinder is closed at the bottom by a lower cap having an upwardly extending plunger received within a portion extending upwardly from the piston. The cylinder also provides an upper cap with a dome and the upwardly extending portion of the piston is reciprocating within this dome, thus defining between the portion of the piston and the dome a first pressure generating chamber, and within the upwardly extending portion of the piston and the plunger of the lower cap a second pressure generating chamber for obtaining hydraulic pressure in both of the strokes of the piston.

Abstract: There is provided an improved airless paint spray pump having an intake, an inlet valve assembly, a pumping chamber, an outlet, an outlet valve assembly, and stroke pumping means for pumping the fluid paint into the pumping chamber through the intake during the intake stroke and through the outlet on the pumping stroke. The inlet valve assembly includes a flat valve which cooperates with a valve seat at the intake and is displaced from the valve seat during the intake stroke of the pumping means and is seated on the valve seat during the pumping stroke of the pumping means. The flat inlet valve replaces the previous ball type inlet or check valve thereby expanding the design capabilities of the pump.

Abstract: In a diaphragm pump with a diaphragm in the form of a rolling diaphragm that separates a delivery chamber from a fluid-filled pressure chamber and that with its peripheral edge is firmly clamped between a casing body and pump cover, and with an oscillating hydraulic piston which is displaceable in a bore of the casing body between the pressure chamber and a hydraulic reservoir, so as to actuate the diaphragm, the rolling diaphragm rolls alternatingly up an outer roll-off cylinder formed by the wall of the pressure chamber and off an inner roll-off cylinder formed by the peripheral surface of a support piston for the rolling diaphragm that is axially displaceable in the pressure chamber, the front surface of which support piston is connected with the corresponding surface section of the rolling diaphragm.

Abstract: A proportioning pump with tandem diaphragm pumps each having a pumpage chamber connected with a source of supply and a mixer and dispensing nozzle, a piston pump for operating each of the diaphragm pumps, a common eccentric drive for the pistons of the piston pumps, the piston pumps having cylinder wall sleeves extending into the hydraulic fluid reservoir, the sleeves having refill ports therethrough communicating between the pump chamber and the reservoir, one of the sleeves being longitudinally adjustable, a double threaded rotary control for the longitudinal adjustable cylinder wall sleeve, bypass pressure relief valves and passages for the hydraulic fluid from the pump chambers returning fluid to the reservoir in the event of excessive pressure, and the pump motor having a variable speed drive for widely varying the speed of the pump.

Abstract: Modification of the existing system of fuel injection pump, of a kind which moves little pistons catching controllable fuel amount, and compress such fuel until it is forced out through an injector. In the pump used at the present, the mentioned pistons force the fuel to move without returning; in the proposed modification these same pistons move a different fluid, with better lubricating features than fuel, in both directions. The alternative displacement of this different fluid produces pressure variations which are indirectly transmited to fuel through an elastic element (14a) that separates the fuel from the other fluid within a hermetically sealed space. Due to the pressure variations induced on the fuel in that way, the fuel is forced to flow toward the injector, by using in its run, suitable inlet (17) and (18) valves. The before mentioned is shown in the figures 2, 2A, 3 and FIG. 2A and 3A.

Abstract: An IV filter and pump assembly having first and second bodies secured into a unitary assembly. The first and second bodies provide a chamber. One of the bodies has an opening therein in communication with said chamber and an inlet port therein. The other of the bodies has an outport therein. The inlet and outlet ports are in communication with the chamber. An inlet valve controls the flow of liquid through the inlet port and an outlet valve controls the flow of liquid through the outlet port. A hydrophobic filter is carried by the unitary assembly and is in communication with the upper portion of said chamber for venting to ambient small quantities of air in said chamber. An actuator supplies a pumping action to the liquid in the chamber so that liquid is caused to be moved out of the chamber through the outlet valve and into the chamber through the inlet valve.

Abstract: In the case of a diaphragm pump, as is more particularly used for dosing or metering liquids and which is provided on the one hand with a dosing chamber with a suction and pressure valve and on the other with a hydraulic working chamber with drive piston and pressure relief valve, both chambers being separated by the working diaphragm, an effective diaphragm protection against excessive deflection and consequently overstressing is obtained in that the diaphragm defines a chamber connected to the working chamber by means of at least one overflow channel and in the vicinity of the overflow channel is guided a valve unit comprising a tappet with in each case one valve disk for the facing openings of the overflow channel and which is in operative connection with the diaphragm.

Abstract: A submersible pumping unit having a diaphragm pumping chamber connected to one end of an elongated tube, the interior of the tube being filled with hydraulic oil and a reciprocable solid of like density, the other end of the tube being connected to an oil chamber including a reciprocable piston for developing hydraulic pressure and flow oscillations at a predetermined frequency, wherein the hydraulic pressure and flow oscillations are transferred via the tube and the solid in the tube to the diaphragm pumping chamber for pumping the liquid in which the diaphragm pumping chamber is submersed.

Abstract: A downhole well pump system comprises a reciprocating piston pump disposed in a fluid conduit in a wellbore which is filled with a driving fluid having a density preferably greater than the production fluid being pumped. The pump cylinder has a transverse partition and a piston assembly including an elongated piston rod extending through the partition and connected at its opposite ends to spaced apart pistons. The pump pistons and the cylinder partition divide the cylinder into a production fluid intake chamber, a production fluid transfer and delivery chamber, a driving fluid chamber and a second production fluid delivery chamber. Production fluid is conducted to the surface through a production fluid conduit disposed coaxial within the driving fluid conduit.

Abstract: A high pressure meter pump system with improved accuracy is provided by subdividing a large meter pump capacity into metered subvolume charges which are incrementally delivered to a high pressure slave pump.This enables the pump sytem to achieve improved accuracy independent of flow rate and therefore increasing the range of flow rates available with acceptable accuracy. Additionally, the pump system self-primes independently of flow rate and therefore does not require degassing of the solvent being pumped.

Abstract: A device for regulating in a practically loss-free manner the pressure and feed volume of a diaphragm pump which is constructed as a hydraulically activatable diplacement pump and is especially suited for feeding a viscous and abrasive or a solids-laden secondary fluid medium. In the device, access is required only to the environment of the primary working fluid medium, and no direct interchanges between the secondary medium being fed and parts of the control device are required. During the pressure phase of the diaphragm pump, a limited quantity of the primary working medium is extracted from a portion of the housing of the device which is in direct and uninterrupted communication with the associated working section, while during the suction phase and in dependence on the overpressure of the primary working fluid medium in the device a compensation is made for the quantity of the primary working fluid medium lost during the pressure phase.

Abstract: An apparatus and method of supplying feedwater to a forced flow boiler or the like as described. A positive displacement pump having a plurality of discrete pumping elements is arranged to pump feedwater from an inlet to the boiler. The pump includes bypass valves which, when open, disable the pumping action of an associated pumping element. Control means responsive to the demand for water in the boiler are arranged to disable a selected number of the pumping elements so that the rate of water supplied by the remaining elements, if operated continuously, would just exceed that required. The control means is further arranged to disable at least one of the remaining pumping elements on a periodic basis so that the ratio of time that the element is enabled to the time for one period multiplied by the water flow rate supplied by said element, if operated continuously, equals the difference between the total demand for water and the rate supplied by the pumping elements enabled on a full-time basis.

Abstract: The present invention relates to an apparatus for delivering a stream of liquid material under pressure. The apparatus includes a base having a motor mounted thereon. A diaphragm pump is mounted on the base and is connected to the motor by a drive assembly. The diaphragm pump has a reservoir tank connected to it. A circulatory system circulates a pump liquid between the pump and the reservoir tank. An air check valve is connected to the circulatory system to allow air to be introduced into the circulatory system when the liquid material is prevented from being pumped out of the diaphragm pump. A collapsible container support is mounted on the base. A liquid material container is removably mounted in the container support for storing a liquid material prior to delivery to the diaphragm pump.

Abstract: A piston filler for metering two fluids intermittently comprising a cylinder having a first and a second inlet conduit and an outlet conduit, means for closing the communication between the cylinder and the first inlet conduit and between the cylinder and the outlet conduit alternately, there being present inside the cylinder a first piston for drawing in a primary fluid from the first inlet conduit and discharging it into the outlet conduit and a second piston for drawing in a secondary fluid from the second inlet conduit which piston has at least one port provided with one or more valves through which the secondary fluid can flow to occupy the space between the two pistons where it can transmit the motion of the second piston to the first piston, and means for conveying secondary fluid from the space between the pistons to the outlet conduit.

Abstract: The invention is comprised of a hydraulically actuated diaphragm pump having a working diaphragm driven by a piston and a working fluid. The working diaphragm, in turn, actuates a tubular diaphragm through a second hydraulic coupling. Material is pumped through the tubular diaphragm as it is compressed and relaxed. The configuration of the tubular diaphragm is such that its cross section gradually transforms from a circular shape at the end portions adjacent to the suction inlet and discharge outlet of the pump to an elliptical shape at its longitudinal mid-point. Since the inner circumference and wall thickness remain constant throughout the length of the tubular diaphragm the direction of flexure is predetermined.

Abstract: An injection pump includes a rotor having a central axial bore and a radial bore and rotated in relationship with an engine. A free piston reciprocably inserted in the central axial bore defines a first and second chamber. The first chamber includes a plurality of first radial passages and a radial spill port and communicate with the radial bore and the second pressure chamber includes a plurality of second radial passages and a discharge passage. A pair of plungers which is disposed in the radial bore is so constructed as to produce, in accordance with the revolution of the rotor, a compression period in which the liquid fuel is pressurized in the first pressure chamber and pressurized fuel in the second pressure chamber is supplied to the engine through the discharge passage, and a suction period in which the liquid fuel is supplied to the pressure chambers.

Abstract: A high-pressure piston pump for liquids, preferably for water, which includes a valve control through a suction and pressure valve, in which the pump pistons are movable at least in the pressure direction through the intermediary of a hydraulic drive. The hydraulic drive encompasses an axial piston machine with an oblique disk construction with an adjustable, rotationally driven inclined disk for adjustment of the stroke, whose drive pistons are each presently coupled through a hydraulic column with one of the pump pistons.

Abstract: A combined surface power unit and velocity actuated valve for a downhole pump is disclosed. The surface power unit generates a series of pulses of pressurized fluid. A power line supplies the fluid pulses to a downhole pump. Within the downhole pump, a piston means is slidably disposed for pumping fluid therefrom. The piston means includes an orifice for permitting fluid flow therethrough. The velocity of the fluid passing through the orifice causes a pressure differential across the orifice and valve means closes for the duration of each pulse. When the valve means is closed, pressure builds up in the downhole pump causing the piston means to move in a power stroke, pumping the production fluid. Between pulses, the pressure of the fluid in the downhole pump drops and a velocity valve opens. When the velocity valve is opened, fluid can flow freely therethrough, and the piston means retracts under the influence of gravity in a re-charging stroke.

Abstract: The present invention relates to a hydraulically controlled diaphragm pump, comprising an intermediate chamber filled with fluid, and a re-filling conduit for said chamber.According to the invention, means are provided for controlling the closing and the opening of the said conduit, which means are constituted by a valve cooperating with a fixed seat through which the said re-filling conduit reaches into the said intermediate chamber. Said valve is mounted for sliding on a rod, which rod is also mounted for sliding longitudinally inside a fixed support in the said intermediate chamber and traverses the said seat, a shoulder of the said rod forming means for moving the said valve and holding it on its seat, an actuating surface of the said rod, opposite the said shoulder, forming the rear of the diaphragm and a spring being coupled between the said support and the said actuating surface for closing the said valve.The invention finds an application in the field of mechanical engineering.

Abstract: A pump for metering two fluids comprising a cylinder having a first and second inlet conduit and an outlet conduit, means for closing the communication between the cylinder and the first inlet conduit and between the cylinder and the outlet conduit alternately, there being present inside the cylinder a first floating solid piston for drawing in a primary fluid from the first inlet conduit and discharging it into the outlet conduit and a second piston for drawing in a secondary fluid from the second inlet conduit which piston has at least one port provided with one or more valves through which the secondary fluid can flow to occupy the space between the two pistons where it can transmit the motion of the second piston to the first piston, and a by-pass for conveying secondary fluid from the space between the pistons to the outlet conduit.

Abstract: A method and device for regulating diaphragm pumps during standby which reduces power input demands during non-delivery standby conditions while assuring a maintenance of working pressure upon a sudden change to a delivery condition which utilizes pressure of the drive fluid as a regulating variable by retaining a portion thereof outside of the drive chamber and using the pressure of the retained portion to control one or both of an intake aperture to the drive chamber or a pressure limiting outlet valve from the drive chamber.

Abstract: A cardiac prosthesis having an hydraulically actuated compressible blood pump. An actuation chamber adjacent the blood pump receives hydraulic actuation fluid from an actuator pump through a three-way ventricular dump valve to compress the blood pump during systole and eject blood therefrom. During diastole the actuation fluid is permitted to drain from the actuation chamber through the three-way valve into a reservoir.

Abstract: A valve arrangement for venting conduits in pumping systems having several pumping units for delivering a gas or vapor generating liquid includes a double-seat valve in which the valving element moves between two extreme closing positions and an intermediate position in which the venting conduit is momentarily open; as the venting conduit is connected at one end with the gas collecting zone in one pumping unit and at the opposite end with the liquid discharging zone below the delivery valve so that the double seat valve is automatically controlled by the pressure difference resulting due to different operational phases of the pumping system.

Abstract: A diaphragm pump having a reciprocating piston, a rotatable cam canted and engaging the piston, and a diaphragm secured to a plunger stem by a screw rotatable relative to the stem. The plunger stem extends into a bore in the piston, the piston bore and plunger stem having a matching configuration preventing rotation of the plunger stem relative to the piston when the diaphragm securing screw is loosened. The piston end engaging the cam is formed as a spherical section positioning the line of engagement with the cam closely adjacent the axial center of the piston, to reduce side thrust.

Abstract: An improved hydraulic pump wherein a piston is mechanically reciprocated by a suitable drive in an oil chamber, and a second piston is caused to reciprocate by the oil pressure developed in the chamber, the second piston also reciprocating in a pumping chamber to cause the pumping of a liquid through the pumping chamber; a diaphragm attached to the second piston provides liquid isolation between the oil chamber and the pumping chamber.

Abstract: A cardiac prosthesis having a hydraulically actuated compressible blood pump. An actuation chamber adjacent the blood pump receives pulses of hydraulic actuation fluid from an actuator pump through a fluid inlet path to compress the blood pump during systole and eject blood therefrom. Between pulses the actuation fluid is permitted to drain from the actuation chamber through an outlet path into a reservoir. Discharge of fluid through the outlet path is controlled by a dump valve which is adapted to close or open the outlet path primarily in response to forces which vary as a function of the flow of actuation fluid through the fluid inlet path.

Abstract: A diaphragm pump is described comprising a reciprocated diaphragm for expanding and contracting a chamber communicating with a passageway connecting the housing inlet and outlet for pumping a fluid therethrough, and a pair of check valves in the passageway permitting the fluid to flow only from the inlet to the outlet. The check valves are disposed along laterally-spaced parallel axes and provide a forward fluid flow through both valves in the same direction along the laterally-spaced parallel axes, the outlet of one check valve communicating with the inlet of the other via a folded section of the passageway having two 180.degree. bends. Such an arrangement enables the diaphragm pump to be constructed in compact and/or miniaturized form.According to another described feature, the diaphragm pump is constructed in combination with the peristaltic pump having an inlet for a liquid to be pumped, and an outlet connected to the inlet of the diaphragm pump. Both pumps are driven by a common drive shaft.

Abstract: A cardiac prosthesis having a hydraulically actuated compressible blood pump. An actuation chamber adjacent the blood pump receives pulses of hydraulic actuation fluid from an actuator pump through a fluid inlet path to compress the blood pump during systole and eject blood therefrom. Between pulses the actuation fluid is permitted to drain from the actuation chamber through an outlet path into a reservoir. Discharge of fluid through the outlet path is controlled by a dump valve which is adapted to close or open the outlet path primarily in response to forces which vary as a function of the flow of actuation fluid through the fluid inlet path.

Abstract: A pulsatile blood pump comprising a disposable power bladder of flexible and anticoagulative material which is provided with a suction port with an inlet check valve and a delivery port with an outlet check valve to constitute a blood pump unit and hermetically sealed container for receiving said blood pump unit, said container being connected to a pulsating mechanism and filled with a pressure transmissive fluid which is subjected to a pulsatile pressure generated by the pulsating mechanism to vary the volume of the power bladder for pulsatile blood delivery.

Abstract: The pressure limiting device is used with a diaphragm pump for controlling the forces applied to the diaphragm. The device includes a body having a pressure control chamber therein. The body has an inlet to the chamber which is adapted to be coupled to a working chamber in the diaphragm pump. The body is provided with a first outlet opening from the control chamber and the body has therein a first poppet valve including a first valve seat at the first outlet opening facing into a larger cross-section first poppet-valve chamber. A first poppet is positioned in the first poppet valve chamber and engages the first valve seat. A spring assembly is situated in the first poppet valve chamber for urging the first poppet against the first valve seat at a first predetermined force. An outlet opening from the first poppet-valve chamber is adapted to be connected to a sump for the working liquid.

Abstract: A high-pressure piston pump in which a low-viscosity working liquid supplied at a first pressure is delivered at a second, ultra-high pressure of, typically, up to 4,000 bars, for use in jet cutting and cleaning operations comprises a cylinder enclosing a first variable volume chamber for a viscous, operating liquid between a main piston and a subsidiary piston, and a second variable volume chamber for the working liquid, between the subsidiary piston and the head end of the cylinder. Operating liquid which leaks from the first chamber during working strokes of the pump and which thus reduces the volume of liquid in the first chamber, is replaced through a non-return valve in the main piston during non-working strokes as a result of the reduction in pressure in the first chamber. The subsidiary piston is provided with a coupling engageable with the main piston for limiting movement of the main piston away from the subsidiary piston during non-working strokes of the pump.

Abstract: A piston diaphragm pump includes a driving fluid chamber and a driven fluid chamber. A flexible diaphragm separates the fluid chambers from one another. An electric motor drives a reciprocating piston through a crankshaft, and the piston moves in the driving fluid chamber from a forward position to a rearward position on a suction stroke and from the rearward position to the forward position on a pressure stroke. An inlet passage extends between a crankcase and the driving fluid chamber, and a normally closed inlet valve in the inlet passage is opened by a cam on the crankshaft when the piston reaches a predetermined position on its suction stroke. The driving fluid in the driving fluid chamber drives the flexible diaphragm back and forth, and the back and forth movement of the diaphragm pumps the driven fluid into and out of the driven fluid chamber.

Abstract: A high pressure pump in which at least one reciprocatingly driven piston acts on a hydraulic fluid communicating with one side of a diaphragm, the other side of the diaphragm communicating with a fluid to be displaced by the pump. The diaphragm is made of elastomeric material, and is relatively thick so that it is substantially self-restoring on the return stroke of the piston even in the event of total blockage of the supply of fluid to be displaced.

Abstract: A pump for pumping insulating oil for oil-filled electric cables in which a driven piston is within and spaced from a tubular bellows which is surrounded by an enclosure. The bellows forms a chamber with the enclosure which contains the cable oil, and the bellows prevents contact of the mechanical parts of the pump, other than an intake valve and a delivery valve, with the cable oil. Preferably, the space between the piston and the bellows is filled with oil to transmit motion of the piston to the bellows. The delivery valve is urged closed by a spring, and the intake valve has an element made of lightweight materials and is held closed by gravity and the cable oil pressure but opens by reason of cable oil pressure reduction and the static pressure of the cable oil fed to the intake valve. Also, a plurality of such pumps operable by a single drive mechanism and a method for evacuating gas from the pump and pump lines in which the delivery valve is operated by a magnetic field external to the valve.

Abstract: Apparatus for an improved diaphragm pump wherein hydraulic shock and mechanical wear to the diaphragm membrane is reduced by providing a circular reed valve member adjacent to the diaphragm. The reed valve member provides a barrier to pressurized hydraulic fluid jets from direct impingement upon the diaphragm membrane, and provides a valve closure member for reducing hydraulic shock effects on the diaphragm membrane.

Abstract: A pneumatic pump adapted primarily as a left ventricular heart assist device includes a flexible bladder with a rigid housing. A pneumatic driver applies rhymical pulses between the bladder and the housing to repetitively collapse the bladder and establish a pumping action through the bladder, in conjunction with check valves in the inlet and outlet to the bladder. Between the driver and the pump there is provided a pneumatic pulse limiter which includes a flexible diaphragm isolating the driver from the pump. Pulses from the driver are transmitted to the pump only through the flexible diaphragm and the diaphragm is constrained to move only within established limits. Regardless of the magnitude of the pulse from the driver, the maximum pulse applied to the pump cannot exceed that corresponding to the maximum displacement of the diaphragm.Between successive pulses, the portion of the system between the driver and the flexible diaphragm is depressurized.

Abstract: A fluid spraying apparatus, such as for use in paint spraying and the like, including a high pressure diaphragm pump, a safety and pressure adjustment valve system, and a high pressure safety spray gun. The valve system includes a valve for maintaining a desired pressure relationship between the sprayed fluid side of the system and the pumping fluid section of the high pressure diaphragm pump. The high pressure safety gun includes a pressure-responsive locking barrel portion which prevents access to the spray tip while the fluid being sprayed is under pressure.

Abstract: Apparatus is disclosed for unloading excess pressures developed in a hydraulic diaphragm pump, wherein the pressure of the pumped fluid is sensed by a control diaphragm connected to an unloading valve which is placed in a passage connecting the hydraulic displacement chamber with a hydraulic oil reservoir.

Abstract: A pumping system is provided in which a low pressure metering pump injects fluid charges into a high pressure pump which in turn operates into a high pressure load. The high pressure pump is designed to always present a low pressure at its input on its intake stroke. This insures that the metering pump will always operate into a low pressure regardless of the load, and will therefore be enabled to always accurately meter charges into the high pressure pump.In various embodiments, the high pressure pump and/or the low pressure pump include spring elements for providing well defined pumping pressures.In some embodiments, an oil reservoir and diaphragm provide a well defined pressure against which the metering pump can operate.

Abstract: A hydraulic fluid control system regulates the delivery rate of feed water to a boiler. A hydraulic actuated diaphragm pump having a plurality of diaphragm working chambers which are interconnected with check valve controlled inlets and outlets pumps the feed water to the boiler. Fluid surges or pulsations are prevented by the use of projection members on the face of the diaphragms and by a variably controlled pressure regulator responsive to the feed water pressure. The delivery rate of hydraulic fluid to the diaphragms controls the actual pumping output. A bypass line including a pressure regulating valve with pilot control and a modulating control valve controls a bypass hydraulic fluid rate which directly corresponds to the pumping output rate.

Abstract: The invention relates to a metering pump assembly having a reciprocable pump element with an adjustable stroke. The pump assembly includes a hydraulic system with two adjustable volume chambers, one chamber being associated with the pump element and the other with a displaceable element having an electromagnetic drive. Adjustable throttle means are provided between the two chambers for adjusting the stroke of the pump element in accordance with the setting of the throttle means.

Abstract: A diaphragm pump apparatus is disclosed, having a mechanically reciprocated piston driving a hydraulic fluid chamber and reciprocating a flexible diaphragm. The apparatus includes a spring-biased expansion volume connected to the hydraulic fluid chamber and a hydraulic fluid replenishing port that opens on predetermined conditions of pressure loading and piston stroke position.

Abstract: A pneumatically controlled liquid transfer system for delivering a liquid from a source to a delivery location, said liquid source being provided with a pneumatic cylinder for driving the liquid from said source, a pneumatically operated pinch valve of the make-before-break type and flexible conduit paths leading through the valve to the delivery location. The make-before-break pinch valve comprises a valve shell having two pistons movable laterally therein. The shell has a window. One piston has a yoke, each arm thereof having a passageway, one aligned with the other. A stop extends between the arms of the yoke. One of the flexible conduits is arranged through the window between the first piston and the yoke and the other flexible conduit is arranged also through the window but within the aligned passageways and between the piston and post. The second piston is spring biased to bear against the second conduit to place same in a normally closed condition. The first conduit is normally open.

Abstract: A fluid transfer device such as a reciprocating pump, preferably of the diaphragm type suitable for use with an airless spray-gun for painting and the like, having a pumping side for the fluid to be pumped and a driving side driven through a piston through a solution or mixture of liquid and gas, such as oil and air. Under throttled or standby operation conditions, reduced diaphragm movement is accommodated without changing the piston stroke by reducing the volume of the driving liquid and by releasing gas from the reduced volume of liquid to prevent vaporization and condensation of the driving fluid itself. A dead space is provided on the pumping side allowing some diaphragm movement into the pumping side even when completely closed so that only a small proportion of driving liquid is released and only a small amount of gas is freed from the driving liquid to accommodate the reduced diaphragm movement during the full piston stroke.