Abstract: A method for controlling the supply flow through a compressed fluid system having a fluid compressor with a inlet valve, and a host system in signal receiving relation with a supply flow sensor and in signal transmitting relation with a compressor controller.

Abstract: A compressed air installation having a normal operating mode and an idling mode includes a feed valve, a feed line which is connected to and receives air through the feed valve, at least one compressor having at least one compression chamber, and at least one inlet valve which is connected to the feed line and supplies air to the compression chamber. The feed valve and the inlet valve are switchable between open positions and one-way positions wherein air can pass through the valve in one direction only. In normal operating mode, the feed valve is in its open position and the inlet valve is in its one-way position, thereby allowing air to enter and exit the installation through the feed valve and the feed line, and to pass from the feed line through the inlet valve into the compression chamber.

Abstract: An installation for the production of pressure has three operating states corresponding to a delivery operation, an idle operation, and a partial delivery operation. The installation contains at least two compression chambers in at least one compressor, each chamber being assigned at least one switchable inlet valve. In the delivery operation, the switchable inlet valves act as check-valves that allow pressure medium to flow into their respective compression chambers. Each compression chamber also contains at least one outlet check valve through which compressed pressure medium flows out to a pressure consuming system in the delivery operation. Each switchable inlet valve also has an idling position that allows pressure medium to flow into the applicable compression chamber and back out again without being substantially compressed. In the idle operation of the installation, each switchable inlet valve switches to its idling position.

Abstract: A pump and associated method including the steps of pre-metering successive quantities of fuel from a reservoir to a positive displacement transfer pump, then actuating the transfer pump to raise the pressure of the successive quantities of fuel by at least about 100 psi, preferably 200-300 psi. Each quantity of fuel which was pressurized in the transfer pump, is delivered to a high pressure pumping chamber so that each pumping bore receives a certain, i.e., predetermined, charge of fuel within a first time interval. A plurality of plungers in the respective pumping bores are then simultaneously actuated to increase the pressure in the pumping chamber to the desired high pressure, preferably at least about 15,000 psi, within a second time interval, and to discharge the quantity of fuel through a high pressure discharge valve. The second time interval is of longer duration than the first time interval.

Abstract: A method for controlling modulation of at least one compressor in a compressor system includes the steps of providing a host controller including a microprocessor for controlling overall operation of the compressor system. The host controller includes a microprocessor and memory for storing system values and transmitting load, unload and modulation commands to the at least one compressor. The at least one compressor includes a compressor controller having a microprocessor in communication with the host controller, a discharge port for discharging compressed fluid from the compressor, and a pressure sensor in communication with the discharge port for sensing the pressure of the compressed fluid discharged therefrom. The sensor is in signal sending relation with the compressor controller. The method also includes transmitting a modulation command from the host controller to the compressor controller of the at least one compressor upon the occurrence of a predetermined event.

Abstract: To influence the periodic stroke movement of the closing element of a valve, a control cylinder working on the closing element in the stroke direction is provided, which can be acted upon or released by a control element periodically with pressure medium. The control element is connected in the supply or discharge conduit of the pressure medium and can variably accelerate or slow its pressure formation or release and with it also the stroke movement of the closing element, at last gradually. Thus a partially or completely automatic control of compressor valves, for example, can be made possible in a simple manner.

Abstract: A positive displacement pump assembly which has an hydraulically controlled intake check valve that is controlled by a three-way solenoid control valve. The intake valve contains a one-way check valve that opens when the pump piston is on an intake stroke and normally closes when the pump piston is on a power stroke. The check valve further contains an hydraulically controlled piston that can open the check valve during the power stroke so that the output fluid of the pump flows to drain. The piston is controlled by the solenoid control valve. The control valve has a pair of digitally latched solenoids. The output pressure of the pump can be regulated by energizing one of the solenoids and applying hydraulic pressure to the piston to open the check valve during the power stroke of the pump. The pump is preferably a dual piston wobble plate pump that incorporates a pair of hydraulically controlled intake check valves that are both controlled by a single solenoid control valve.

Abstract: A valve disabler for use in high pressure pipe cleaning systems. The valve disabler of the present invention serves to disable a single cylinder in a multi-cylinder plunger pump so as to generate pulsatile pressure surges within a hose member. The pulsatile pressure surges cause the distal end of the hose member to move in a serpentine manner, thus allowing the hose member to negotiate down a tortuous path within the pipe without stalling or becoming otherwise impeded.

Abstract: A pump which has a digitally controlled internal by-pass valve. The pump includes a housing which has a pumping chamber that contains a piston which pumps fluid from an inlet port to an outlet port of the housing. The pump also has an intake valve that moves to an open position when the pump draws in fluid and moves to a closed position when the piston pumps the fluid through the outlet port. The intake valve can be maintained in the open position by a separate hydraulic system so that the piston pumps fluid back through the inlet port and by-passes the outlet port. The separate hydraulic system includes a three-way solenoid control valve which directs fluid to the intake valve to open the valve. The control valve may contain a pair of solenoids which latch an internal spool to control the flow of fluid to the intake valve. The spool can be latched into position by a digital pulse that is provided by an electrical controller.

Abstract: A compressor has a housing divided by a valve plate into a first chamber and a second chamber. The second chamber has a suction chamber and a discharge chamber. The valve plate includes discharge conduits communicating the first chamber with the discharge chamber and suction conduits communicating the first chamber with the suction chamber. A suction valve member bends to open and close the suction conduits in response to changes in discharge chamber pressure and the resulting pressure difference between the first chamber and the suction chamber. A suction valve control mechanism includes a regulator for regulating opening and closing of the suction valve between a maximum opening position and a minimum opening position in response to changes in discharge chamber pressure.

Abstract: A fluid delivery system is disclosed which includes a pump and a fluid delivery set. The fluid delivery set includes a stop cock valve, and the pump includes a valve actuation unit into which the stop cock valve is positioned for operation of the system. The valve actuation unit includes a valve receiving mechanism which requires the valve to be closed in order to be inserted into or removed from the valve actuation unit, thereby preventing accidental free flow of fluid at all times. The fluid delivery set may also include an auxiliary fluid source to allow periodic flushing of the fluid delivery line, and the valve actuation unit can be programmed by the pump to automatically initiate periodic flushing cycles if desired.

Abstract: A plate mounted to a reciprocable shaft has a plurality of straight fingers (a) coupled thereto and (b) extending perpendicularly therefrom, and each of the fingers is separately detachable from the plate to simplify and facilitate maintenance and repair. Further, the fingers are identical, whereby manufacturing and stocking requirements are minimized.

Abstract: A booster compressor system modulates discharge pressure with a proportional regulator in fluid communication between the compressor discharge and a servo control for a valve to the compressor inlet. The servo control comprises a double acting piston connected to a valve control rod. In one embodiment, the proportional regulator is of a negative signal type and communicates to a side of the piston for urging the piston to a valve opening position. A valve closing pressure is applied by a non-relieving regulator in fluid communication between the compressor discharge and the other side of the servo control piston. As the discharge pressure increases, the proportional regulator out let pressure decreases thereby resulting in the servo control allowing the intake valve to the compressor inlet to close. This, in turn, reduces the compressor discharge pressure thereby resulting in the proportional regulator controlling the valve to partially open once more.

Abstract: The inventive device produces compressed gas. It is provided with a compressor, wherein the compressor has a compression chamber (25), a suction chamber (10) and a pressure chamber (6). The compression chamber (25) can be connected to the suction chamber (10) via a suction valve (12, 21, 54) and to the pressure chamber (6) via a pressure valve (3). When the receiving-end pressure reaches a predetermined level, the pressure chamber (6) is connected to a compressed-air supply container (44). This connection is via a device for the discontinuation of compressing action (23, 51). In addition, the pressure in the pressure chamber (6) is monitored by a control valve (26), which is a sensing device with a control output (38). The sensing device (26) is designed to produce a control signal at the control output (38), when the pressure in the pressure chamber (6) or compression chamber (25) of the compressor reaches or exceeds a predetermined value.

Abstract: A compressor has a swash plate tiltable between maximum and minimum inclining angles with respect to a plane perpendicular to an axis of a drive shaft according to a difference between pressures in a crank chamber and a suction chamber. An internal gas passage includes the crank chamber, the suction chamber and a discharge chamber. The internal gas passage is connected to an external circuit separately provided from the compressor. The rotation of the drive shaft is converted to a reciprocating movement of a piston to vary a capacity of a cylinder bore. The piston compresses a gas supplied from the external circuit to the internal gas passage and discharges the gas to the external circuit. A inhibiting apparatus inhibits the circulation of the gas through the internal gas passage and the external circuit when the swash plate is located between the minimum inclining angle and a first inclining angle. The first inclining angle is greater than the minimum inclining angle of the swash plate.

Abstract: A spool 9 is connected to the rotating shaft 1 so that the spool 9 is slidable with respect to the shaft 1, while the rotating movement of the shaft 1 is transmitted to the spool 9. The spool 9 is formed with a first recess 9-3 of a reduced circumferential extension for obtaining a reduced compression capacity and a second recess 9-4 of an increased circumferential extension for obtaining a full capacity of the compressor. An intake pressure is always opened to a side of the spool, while an intermediate chamber is formed on the other side of the spool. A spring 10 is arranged for causing the spool 9 to be moved toward the intermediate pressure chamber. At the instant the compressor is brought into operation, introduction of the intake gas occurs via the first recess 9-4, thereby obtaining a compression capacity of 3 to 5% compared to the full capacity of the compressor.

Abstract: A fluid delivery system is disclosed which includes a pump and a fluid delivery set. The fluid delivery set includes a stop cock valve, and the pump includes a valve actuation unit into which the stop cock valve is positioned for operation of the system. The valve actuation unit includes a valve receiving mechanism which requires the valve to be closed in order to be inserted into or removed from the valve actuation unit, thereby preventing accidental free flow of fluid at all times. The fluid delivery set may also include an auxiliary fluid source to allow periodic flushing of the fluid delivery line, and the valve actuation unit can be programmed by the pump to automatically initiate periodic flushing cycles if desired.

Abstract: An apparatus is provided for supplying vacuum and compressed air utilities for dental and medical applications. The apparatus comprises a reciprocating piston air compressor for simultaneously producing vacuum pressure at an intake valve thereof and compressed air at an exhaust valve thereof, the vacuum being used to draw air, water vapor, and effluent such as bodily fluids and tissue through a conduit. Effluent and water vapor are separated from the air stream and discharged into a drain. The desired vacuum is maintained by a regulator carried by the compressor. A receiver is also carried by the compressor for receiving and storing the compressed air from the compressor.

Abstract: An induction regulator valve is incorporated in the induction manifold of a compressor to provide for infinitely variable regulation of the output from the rotary type compressor, in particular the screw-type compressor. The closing piece of the induction regulator valve can be adjusted by means of an actuator system. To improve this regulation performance of this system, in particular to reduce its sensitivity when the regulator valve is almost closed, the spring system is formed so that its stiffness varies along the length of its spring path, the stiffness of the spring system being smaller when the induction regulator valve is open than when it approaches the closed position of the closing piece of the induction regulator valve.

Abstract: An intake control valve for a screw-type compressor is built into the intake line, which it alternatingly opens or closes. The intake control valve, designed as a double seat valve, has a locking body (17), to which are assigned two opposing valve seats, namely a return flow seat (7) and an intake seat (9). Upon starting the screw-type compressor, the locking body (17) is pulled onto the intake seat (9) by means of the resulting intake pressure. As soon as a specific operating pressure is reached, the locking body (17) is lifted from the intake seat (9) by means of the pressure medium by way of a control cylinder (10) with a control piston (11) and moved into an intermediate position between its two seats (7, 9), so that the screw-type compressor can totally transport.

Abstract: A cylindrical gas compressor has inlet valves confined therewithin, at opposite ends thereof, and discharge valves, shaft-mounted therebetween, for reciprocation to ingest and compress admitted gas. Outboard of the inlet valves are circular plates from which extend a plurality of fingers. The plates are confined within chambers in the compressor, and radial ports are provided for admitting pressured fluid to the plates to cause them to move inboard, whereby the fingers penetrate the inlet valves and remove the inlet valve valving elements off the valve seat, effecting unloading of the inlet valves. Springs hold the plates outboard of the inlet valves, to allow the valves to function normally-loaded, in the absence of the plate-displacing, ports-admitted, pressured fluid.

Abstract: The invention relates to a valve-controlled positive displacement pump having valve triggering, which permits the forced opening or keeping open of an inlet valve, operating in the manner of a non-return valve, of a displacer working space, so that the displacer working space remains connected to the inlet side of the unit even during the working stroke of the displacer, and the assigned displacer is not able to work efficiently. The design according to the invention is particularly suitable for radial piston pumps.

Abstract: Method for the continuous control of the delivery rate of reciprocating compressors by occasional holding-open of the suction valves by a lifting device (8), which is actuated by a lifting force supplied by a pressure medium. In order to take into consideration the properties of the gas delivered and to adapt the control method in a corresponding manner, the magnitude of the lifting force is chosen depending on the drive power respectively received by the drive motor (11) of the compressor (3). The lifting force may be limited depending on the drive power. An apparatus for carrying out the method includes a compressor system (3), which includes at least one cylinder (4-7) with a lifting device (8) for the suction valve, which is actuated by a lifting force applied by a pressure medium, the magnitude of which can be determined by a controller (10). The drive power received by the drive motor (11) of the compressor (3) is supplied to the controller (10) as a signal.

Abstract: Displacement control of a multi-piston fluid pump is achieved by real time control of electrically selectable inlet poppet valves in one or more of the cylinders. Microprocessor control permits desired variable output characteristics to be matched. An electrically actuable poppet valve using an annular permanent magnet to latch to a solenoid is described.

Abstract: A valve vane is provided, where the valve vane is movable along the surface of a casing part and is driven by a dog follower, guided in a slot of the casing part, wherein the slot is furnished at least at one end, and wherein a flat slider is required for a sealing of the casing part. Such a flat slider requires by itself a substantial structure. The invention valve vane (6) is structured such that it covers the slot (12) in each phase of its motion. The invention structure is particularly suitable for being employed in a inlety valve system of a compressor.

Abstract: The Assembly is formed of individual, radially-fingered plates, set upon a body, in surmounting relationship, and fastened to the body by a central bolt. The Method calls for the provisioning of the body and the radially-fingered plates, setting the plates upon the body, fastening the plates thereon, and bending the fingers, angularly from their plates, into a common parallelism, with the ends of the fingers all terminating in a common plane. The kit sets forth the components for an Assembly: a plurality of radially-fingered plates, a body, and a fastener for fixing the plates onto the body. The Plate is flat, having a uniform thickness, with radially-extending fingers, and apertured in a central portion thereof.

Abstract: To adapt a compressor valve to varying operational conditions of the compressor, particularly to varying numbers of revolutions and/or the respective specific weight of the transported gas, a process and a compressor valve for executing the process are provided. The process is that a compressor drive at various numbers of revolutions or transporting gas with varying specific weight, the spring force--possibly resulting from several spring forces--acting during operation on the plug in a closing direction and/or the lift of the plug is forcefully reduced with falling number of revolutions or increasing specific weight the process is reversed either continuously or in steps.

Abstract: A variable delivery compressor containing a plurality of compression chambers and reciprocatory compression pistons is adapted for use in an air-conditioning circuit of a vehicle. The compressor has a suction chamber communicating with the compression chambers by way of a plurality of suction valves, some of which are capable of being deformed by a valve pressing mechanism from a first position, where the refrigerant is compressed, to a second position where the compression of the refrigerant is partially ineffective. The valve pressing mechanism contains an axially movable spool actuated by an actuating unit controlled by a cooling-load responsive control unit.

Abstract: A variable-delivery compressor having plural compression chambers whose volume is changed as a rotor is rotated in a housing to compress a gas sucked through a suction port and deliver the compressed gas through a discharge port, comprising: a by-pass passage for communication between a compressing and a sucking compression chamber of the plural compression chambers; a device for changing the position of the discharge-side extremity of an opening of the by-pass passage on the side of the compressing compression chamber, in the circumferential direction of the rotor, to retard the compression start timing of the compressing compression chamber; and at least one of a variable flow restrictor device associated with a suction passage communicating with the suction port to adjust a flow of the gas which is sucked through the suction passage, and a pressure relief device including a pressure relief passage and a switching device for closing and opening the pressure relief device.

Abstract: An isolation valve is provided for use in a pneumatic system having an air compressor operable in normal and unloading modes, an air dryer, a reservoir of charged air, and a governor. The isolation valve includes a housing provided with an internal cavity and having a first port to the cavity communicating with a first port of the compressor, a second port to the cavity communicating with an inlet port of the dryer, and a third port to the cavity communicating with a port of the governor. A pneumatically responsive primary valve member is mounted within the cavity for movement between open and closed positions with respect to the housing second port. The primary valve member is provided with an internal passage having one end in communication with the housing third port and a second end in communication with the housing cavity. A pneumatically responsive secondary valve member is mounted within the passage for movement between blocking and unblocking positions.

Abstract: A lifting device for controlling the movement of the closure plate of a compressor valve comprises a first gripper part which is connected to the compressor valve to be movable toward and away therefrom; a regulating spring which is in contact with the first gripper part to bias it toward the compressor valve; and a second gripper part which is movable with respect to the first gripper part and the compressor valve, the second gripper part including lift elements having lifting prongs which can contact the closure plate, tension screws which connect the lift elements to the first gripper part and provide end stops for the movement of the lift elements, and damper springs which damp the relative movement of the lift elements relative to the first gripper part.

Abstract: A high pressure metering pump has a duty cycle consisting of an aspiration portion where liquid is aspirated into a pumping chamber, a compression portion where the aspirated liquid is compressed to feed pressure, a feed portion where a part of the compressed liquid is expelled out of the pumping chamber, and a decompression portion where the liquid remaining in the pumping chamber is expanded to aspiration pressure. A measurement and control apparatus for the pump comprises a controller for adjusting and keeping constant the mean flow rate of the pumped liquid on the aspiration side or on the high pressure side of the pump. The apparatus further comprises a detector for detecting the transition point between the compression and feed portions and/or between the decompression and aspiration portions. The detector derives a control signal for the pump speed and for the optimal opening instant of an externally actuated input valve of the pump from the phase relationships of said transitions.

Abstract: A gas compressor has cylinders in which gas is compressed by pistons. Each cylinder has a suction valve and an exhaust valve to admit uncompressed gas and expel compressed gas. The suction valve includes a suction valve plate which repeatedly moves toward and away from the top end of the cylinder between closed and open positions, respectively. Apparatus to control compressor capacity includes an unloader mechanism to selectively prevent the suction valve plate moving to fully closed position to thereby unload the cylinder and reduce compressor capacity. The unloader mechanism comprises an unloader piston movable in an unloader cylinder in response to system conditions to move a linkage which determines the closure position of the suction valve plate. The linkage includes a pivotable lift arm biased toward a position which allows full closure of the suction valve plate and is movable by the unloader piston to another position which prevents full closure of the suction valve plate.

Abstract: An oil-sealed vacuum pump comprises an oil circuit for supplying a pump chamber and bearings of the vacuum pump with oil. The oil circuit includes first and second branch conduits leading to the bearings and the pump chamber, respectively. The vacuum pump further has an oil pump coupled to the oil circuit for driving oil therethrough, a valve assembly coupled to the oil circuit for shutting off oil supply to the pump chamber during standstill of the vacuum pump, and a pressure reducer coupled to the oil circuit for reducing the oil pressure to environmental pressure. The first branch conduit leading to the bearings is situated upstream of, and the second branch conduit leading to the pump chamber and the valve assembly are situated downstream of the pressure reducer as viewed in the direction of oil flow in the oil circuit.

Abstract: A control system for varying the volume of fluid discharged from a variable displacement hydraulic pump having a plurality of reciprocating pistons. Each piston includes an inlet check valve which controls the flow of fluid from an inlet supply line to the piston chamber, and an outlet check valve which controls the flow of fluid from the piston chamber to a discharge line. The displacement of the pump is controlled by a series of actuator members which regulate the working pressure developed by each piston by controlling the positions of the inlet check valves. Each actuator member is movable between a first position wherein it permits an inlet check valve to close and enable its corresponding piston to develop working pressure in the piston chamber, and a second position wherein it opens the inlet check valve to prevent the development of working pressure in the piston chamber.

Abstract: The pumping capacity of an unloadable air conditioning compressor is switched between full and part capacity states. The part capacity state is established during on/off cycling of the compressor, and air conditioning load conditions are sensed during operation of the compressor to control capacity switching in a manner to provide efficient and responsive performance. Refrigerant pressure at the evaporator outlet is used to control on/off cycling as well as capacity cycling, and the rate of decrease of such pressure is used as an indication of the air conditioning load.

Abstract: An engine having a working chamber and a combustion chamber and a method for operating it are disclosed. The amount and compression ratio of air entering the combustion chamber are controlled by valves at the working chamber. The maximum possible amount of air is inducted into the working chamber, and then air is discharged until an amount necessary for the existing load on the engine remains. This remaining air is then compressed to a predetermined constant compression ratio at which it enters the combustion chamber. A proportional amount of fuel is supplied, and the resulting combustion gas is then transferred to do work in the working chamber. The amount of combustion gas transferred is sufficient to maintain a substantially constant pressure in the combustion chamber.

Abstract: A hydraulic pump having spring loaded valves utilizes a spring providing a constant spring force and a spring providing a varying spring force. The varying spring force depending upon the position of the pump piston. The pump suction valve opens after a variable delay relative to the beginning of the piston suction phase when the pressure prevailing in the pump's dead chamber falls below a predetermined value. Abrupt decompression to the dead chamber is therefore avoided resulting in reduced energy consumption and noise level.

Abstract: A vacuum pump comprises a suction nipple valve including a cylinder, a piston slidably received therein and a movable valve closing member operatively connected to the piston. The vacuum pump further has a pressure medium conduit having a first end communicating with the cylinder; an inlet opening at a second end of the conduit for pressure medium to flow through the inlet opening to the piston; a control arrangement for closing and opening the inlet opening dependent upon run or standstill of the vacuum pump. In the closed state of the inlet opening an oil quantity is maintained above the inlet opening.

Abstract: A unique system is disclosed which controls a pressure in a pneumatic pressure supply line of a vehicle in response to both a pressure developing in an accumulator (12) included in the supply line and an engine load, so that a compressor (10) for providing the pressure is activated under light load engine operation, as when air brakes are applied, to effect an engine brake and to elevate the accumulator pressure for reducing the total energy consumption and, therefore, total fuel consumption. A pressure feedback line (16) communicates a pressure in the accumulator (12) to an unloading pressure control valve (32) through a solenoid operated valve (34), which is controlled in response to an output of an engine load sensor (42) and that of a pressure sensor (44). Under heavy load engine operation, the valve (34) is opened at a first pressure level during an elevation of the pressure and closed at a second pressure level which is sufficiently lower than the first during a drop of the pressure.

Abstract: A compressor having a starting load reducing apparatus comprises a main compressor body for compressing gas obtained under suction from an intake chamber through an intake valve within a compression chamber, and ejecting the compressed gas through an outlet opening, a motor for driving the main compressor body, a switch for starting the motor by closing, a solenoid mechanism operated by the closing of the switch, for forcibly communicating the compression chamber with the intake chamber, to put the main compressor body into a non-compressing operational state, and a positive thermally sensitive resistor element connected at a stage before a coil of the solenoid mechanism. The solenoid mechanism operates after the switch is closed until the time when the resistance of the positive thermally sensitive resistor element reaches a predetermined resistance.

Abstract: Apparatus for modulating the capacity of a reciprocating compressor having a cylinder chamber and a valve assembly extending over the cylinder chamber, defining fluid inlet and outlet paths, and including a suction valve for regulating vapor flow through the inlet path. The capacity modulating apparatus comprises a lever, a fulcrum, and control means. The lever extends through the fluid inlet path and above the suction valve, and has a first end located outside the valve assembly and a second end engaging the suction valve. Both the fulcrum and the control means engage the lever, and the control means is provided for applying a variable force to the lever wherein the lever transmits the force to the suction valve to urge the suction valve to an open position.

Abstract: In an hydraulic system an unloader valve is disposed in a supply line between a pump and an hydraulic accumulator. The unloader valve is operative to prevent the accumulator from being overcharged and to allow the pump to re-charge the accumulator should the pressure stored therein fall below a desired minimum value. The unloader valve incorporates a control valve comprising a spool and a pressure responsive slave which is operated by fluid pressure under the control of the control valve. The spool is movable between a first position in which the accumulator is isolated from the slave so that pump pressure is supplied to the accumulator and acts through a membrane on a trapped volume of gas under pressure, and a second position in which fluid pressure from the accumulator acts on the slave to unload the pump. The membrane of the accumulator acts directly on the spool to control movement of the spool between the two positions.

Abstract: A rotary oil sealed compressor including an unloader valve to restrict or close the compressor intake when the compressor pressure rises above the normal working pressure (i.e. when the demand for compressed air drops or ceases) and a minimum pressure valve arranged to ensure that the pressure within the compressor never drops below a predetermined minimum value, further includes venting means responsive to the rise in pressure in the compressed air supply line above a predetermined value exceeding the normal working valve arranged to vent the delivery and compression spaces of the compressor. Thus under no-load conditions the pressure within the compressor is reduced to a relatively low level which considerably reduces the power consumed when the compressor is idling.

Abstract: A multi-cylinder pump for a cryogenic liquid is provided with an unloading system in which the inlet valve of each cylinder can be selectively held open or permitted to close. In the closed position, the operation of the cylinder is normal; while, in the open position, the liquid fails to attain sufficient pressure to exit through the outlet valve, thereby deactivating the cylinder. Preferably, the unloading system comprises several plunger assemblies which may be extended in order to engage the inlet valve and hold it in the open position. Each plunger assembly may be activated by means of a manual thumb screw or in accordance with the change in a pressure differential acting on the plunger. Alternatively, the plunger assembly may be activated electronically by means of a solenoid.

Abstract: In an hydraulic system an unloader valve is located in a line between a pump and an hydraulic accumulator. The unloader valve is operative to prevent the accumulator from being overcharged and to allow the pump to re-charge the accumulator should the pressure stored therein fall below a desired minimum value. The unloader valve incorporates a control valve comprising a spool, and a pressure responsive slave which is operated by fluid pressure under the control of the control valve. A spring acts to bias the spool into a first position against pressure in a control chamber into which fluid is pumped through a first one-way valve. A second valve in series with the first valve is located between the first valve and an exhaust port for connection to a tank for fluid. The slave comprises inner and outer concentric piston parts which are relatively movable axially and of which the inner part is adapted to open the valve to unload the pump.

Abstract: A piston pump mechanism for use in positive pressure and vacuum pumping systems for pumping various gases such as air, freon, natural gas, etc. The pump mechanism incorporates an inlet and discharge valve system that substantially eliminates any unpurged or unswept volume of gas within a pump cylinder during each reciprocating stroke of the pump piston. The pump mechanism also incorporates a control spool that floats within a pump head and has a sealed flexible interconnection with the discharge valve that allows the discharge valve to seek optimum seating engagement about the entire periphery of the cylinder. The valve control spool may be pressure balanced or controllably unbalanced, as desired, for influence of the discharge valve. The spool also provides for inlet of gas to an inlet valve that may be incorporated into the discharge valve.

Abstract: A separate valve, rotatable with a pump control valve in a multiple plunger type fuel injection pump used to sequentially supply fuel to a number of fuel injection nozzles, is actuated by a solenoid to control fuel spill from each plunger whereby to control quantity and timing of injection.

Abstract: A piston pump includes a fluid flow control system positioned between the fluid intake duct and the intake aperture of the piston cylinder, the control system including a cylindrical sleeve which is in fluid communication with the intake duct, a valve piston movable in the cylindrical sleeve, a valve stem connected to the intake valve in the piston cylinder extending through both the intake aperture and the valve piston, a first spring positioned between the valve piston and the piston cylinder, a second spring positioned between the piston cylinder and the end of the valve stem, and a fluid by-pass control device for regulating the amount of fluid passing from the intake duct around the valve piston to the intake aperture.

Abstract: An air compressor has an inlet supplied with pressurized air, and is operable in a pumping mode and in a non-pumping unloaded mode. Unloader means is provided for placing the compressor in its unloaded mode. When the compressor is placed in its unloaded mode, diversion valve means operates for blocking communication of the inlet with the pressurized air supply and establishing communication of the inlet with atmosphere.