Abstract: The present invention is a more efficient compressor control system and a more efficient method of operating a multiple compressor system because the method and control system are a function of both the system pressure and the volumetric flow rate capacity of the system. Specifically, a compressor is loaded or unloaded from the compressor system after sensing the actual system pressure and volumetric flow rate capacity. The inventor(s) of the present invention have discovered that it is more efficient to control the compressors upon sensing both the pressure and volumetric flow rate capacity of the fluid. Moreover, controlling the compressor system in response to sensing both the pressure and volumetric flow rate capacity of the fluid insures that the appropriate blend of compressors is loaded to the system in order to produce the most suitable pressure and volumetric flow rate capacity.

Abstract: A fluid pumping system for an automatic transmission includes a primary pump operable to draw fluid from a sump to a main delivery line to a main hydraulic circuit of the transmission. A main circuit pressure regulator regulates pressure to the main circuit and exhausts excess fluid to a secondary delivery line to a secondary hydraulic circuit of the transmission. A secondary pump operates to draw fluid from the suction line to a discharge line. A check ball valve operates to permit one way flow from the discharge line to the secondary delivery line. A secondary circuit pressure regulator regulates pressure to the secondary circuit and operates to exhaust flow from the discharge line to a return line or from the discharge line and the secondary delivery line wherein the return line is in continuous fluid communication with the suction line to reduce hydraulic horsepower expended by the secondary pump.

Abstract: In a pump equipment having one or more rotary pumps for a hydraulic circuit, the intake port is communicated with the shaft hole for inserting the drive shaft and fluid flows through the shaft hole to a fluid groove provided in inner surfaces of the pump room for the purpose of lubrication. To prevent fluid leakage to the outside, first and second oil seals are disposed for filling the clearance between the drive shaft and the shaft hole and, preferably, a communicating conduit is provided between the first and second oil seals to transmit the fluid leaked through the first oil seal to a low pressure fluid conduit of the hydraulic circuit. In particular, in the pump equipment having plural rotary pumps, the respective discharge ports of the rotary pumps are located at the points which are nearly symmetrical with respect to the center axis of the drive shaft to counterbalance each other, the reaction forces against the drive shaft to be produced by the high pressure at the respective discharge ports.

Abstract: A pump device including a plurality of pumps having respective different operating characteristics, and a pump control device for controlling the plurality of pumps, wherein the pump control device includes a control changing portion operable in response to detection of a failure of at least one of the pumps, for changing a manner of controlling at least one of the other of the pumps such that at least a portion of the operating characteristic of each defective pump is compensated for by the changed manner of controlling each normal pump. The pump device may be used in a hydraulic pressure control system as used for a hydraulically operated braking system for an automotive vehicle.

Abstract: A pump system is provided where low pressure (4) and high pressure (6) pumps are coaxially mounted to receive motive power from a shared drive (300). The drive shafts are arranged such that one extends within a void in the other and both have shear regions such that, in the event of torque overload, either shaft can shear so as to disconnect the drive to it's associated pump while the other pump and shaft can continue to work.

Abstract: An exemplary oil delivery system comprises a dual pump system configured for reducing the buildup of pressure by unloading one or both pumps, thus reducing the buildup of heat within the hydraulic system. The dual pump system is configured for delivering oil in combination to a single hydraulic system or to two completely separate hydraulic systems. In addition, the oil delivery system can also be configured to unload one or both of the pumping sections at a pre-determined speed to again limit the flow to any existing open centered hydraulic system. As a result, the oil delivery system recirculates oil back to the reservoir and/or the inlet to the pump in the absence of a buildup of pressure, and thus an absence in the buildup of heat to conserve energy.

Abstract: A compressor protection and control subsystem for a rotary compressor provides temperature pressure, mis-wiring and vibrational protection for the scroll machine. The vibrational protection comprises a vibration sensor which is integrated on the circuit board of the protection and control subsystem. The vibration sensor, in conjunction with at least one timer, monitors the vibrations of the scroll machine and will shut down the machine when excess vibrations are sensed over a prespecified period of time. The temperature system monitors operating temperature conditions the pressure system monitors operating pressures and the mis-wiring system monitors the power supplied to the compressor. Once an undesirable characteristic is identified, the operation of the scroll machine is stopped. These protection systems are integrated into a single subsystem which identifies the reason of shutting off the scroll machine in order to simplify repairs needed.

Abstract: They are characterized in that, when the pressure at the measurement point reaches or exceeds the start-up pressure value and/or when the flow provided by the pumping devices is lower than the consumption flow, the flow provided by the station increases by a step, and, when the pressure at the measuring point reaches the stop pressure value and/or when the flow provided by the pumping devices exceeds the consumption flow, the flow provided by the station reduces by a step. According to another embodiment, a pumping device stops or remains in operation without pumping (“stand by”) when said pumping device is in operating conditions such that there could be a reduction of life of the pumping device or overheating of same. Significant energy saving and longer useful life of pumping devices is achieved.

Abstract: A system allows pumps to run in parallel and preventing back flow through a non-operational pump. The system includes a first pump in parallel with a second pump. The system further includes a check valve in fluid communication with the first pump for preventing flow through the first pump when the first pump is not operating. The system further includes a sensing valve in fluid communication with the first pump and the second pump. The system also includes a load sharing valve in fluid communication with the check valve, the sensing valve, and the second pump for controlling a system flow, wherein the system flow is provided by the first pump when the second pump is not operating, and wherein the system flow is provided by the second pump when the first pump is not operating, and wherein the system flow includes a portion of flow from both the first and second pumps when both pumps are operational.

Abstract: A three-way valve is configured as a solenoid operated diverter when the solenoid is used in parallel with a poppet valve. When the diverter is in a first mode, hydraulic fluid entering a first port exits the valve through a system outlet port while hydraulic fluid entering a second port exits through a second port. The solenoid valve is positioned to close the second port when energized in order to shift the system to a second mode. When the solenoid valve is energized to close the second port so that all of the fluid entering the second port opens the poppet valve and exits through the system outlet. By utilizing a poppet valve in parallel with a solenoid valve rather than a valve spool, the three-way diverter is able to operate at higher pressures and higher fluid flow because Bernoulli effects which cause closing of valve spools used in prior art three-way valves do not adversely affect the poppet valve.

Abstract: A valve spool (70) for an oil pump assembly (10) that includes a pilot pressure relief valve (80) to provide pilot pressure relief that increases the stability of the pump assembly (10) and eliminates the delay between the change in the discharge pressure and the associated response to the pilot pressure. The valve spool (70) operates in response to the pilot pressure to increase or decrease the pump discharge pressure during vehicle operation. A chamber (72) within the valve spool (70) is in fluid communication with the discharge flow and pressure at one end and the pilot pressure at the other end. When the pilot pressure exceeds the discharge pressure, the relief valve (80) opens, allowing the discharge pressure and the pilot pressure to equalize.

Abstract: A pump which can operate in a number of different modes, wherein each mode corresponds to a different output of the pump. The pump may have a plurality of pump chambers located within a pump housing. The pump chambers may be arranged in fluid communication with an inlet port and an outlet port. Each pump chamber may have a pumping device which draws in fluid from the inlet port during an intake stroke and pushes fluid through the outlet port during a discharge stroke. The pump may also have a plurality of electronically controlled valve assemblies which control the output of the pump. Each valve assembly can be selectively switched to a by-pass state for by-passing the fluid flowing from the pump chamber back to the inlet port during the discharge stroke of a pumping device. The pump may operate in a number of different modes which each have a distinct output. Each mode may be defined by which valves are chosen to be switched to their by-pass state.

Abstract: A pumping system and method according to which a plurality of housings are connected together, with each having an inlet and an outlet for respectively receiving and discharging the liquid to be pumped. A single shaft is driven by a motor and extends though all of the housings, and a plurality of rotors are respectively disposed in the housings and are connected to the shaft for rotation therewith. When the shaft is rotated, the rotors pump liquid passing into their corresponding housings from its inlet, through the housing and out its outlet.

Abstract: The invention relates to a fuel pump assembly having a low-pressure region (ND) with at least one low-pressure pump-and a high-pressure region (HD) with at least one regulated-quantity high-pressure pump, which pumps a quantity of fuel required to compensate for the quantitative balance in the high-pressure region, the quantity regulation being effected via a metering unit which is disposed between the low-pressure pump and the high-pressure pump. In order, by simple and sturdy means with high availability and a long service life, to prevent the fuel quantity in correctly pumped by the metering unit at certain operating points from reaching the high-pressure region, the invention proposes that the pumping flow of the low-pressure pump is greater than the pumping flow of the high-pressure pump; that a fuel return line branches off between the metering unit and the high-pressure pump and discharges into the inlet of the low-pressure pump; and that a control element is disposed in the return line.

Abstract: A system is provided for closed-loop control of a plurality of metering pumps driven by a single source of pressurized fluid. Feedback signals are generated that are proportional to output flow rate from each metering pump, such as velocity of a movable element of the pump with respect to a stationary element. Flow control valves are coupled between the source of pressurized fluid and the metering pumps. A controller receives the feedback signals and regulates flow from the flow control valves to each metering pump to maintain a desired level of output flow. The source of pressurized fluid may include a pressure compensated positive displacement pump having a maximum output flow rate at least equal to the anticipated combined flow rate of drive sections of the metering pumps.

Abstract: An electronic control system is disclosed to control and to prevent damage to a standalone or a network of oil free, two stage compressor packages. The electronic control system uses pressure and temperature sensors to detect actual shutdown conditions or predict shutdown conditions based on the operating state of the compressor package and the current temperatures or pressures of the air at strategic locations in the compressor package. It has been determined through experimentation that, if the pressure at the inlet of the stage two compressor is less than the discharge pressure of the stage two compressor by more than an allowable value, then a high temperature condition will occur in the stage two compressor and cause the compressor to seize.

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 multistage vacuum pump unit having a plurality of separate single-stage pumps connected in series with each other by exhaust pipes, the exhaust pipes each connecting a suction port of one of the adjacent single-stage pumps with an exhaust port of another of the adjacent single-stage pump; motors for driving the separate single-stage pumps respectively; driving device for varying a revolution of one of the single-stage pumps that is at least in contact with an atmospheric side; driving current detection device for detecting a driving current of the motor for driving the single-stage pump that is in contact with the atmospheric side; pressure detection device for detecting a pressure at a vacuum-side inlet; and control device for controlling revolutions of the motors of the single-stage pumps based on the pressure detected by the pressure detection device.

Abstract: This invention relates to a fluid transfer system including two elongated fluid transfer chambers, fluid inlet and outlet arrangements at each end of each chamber, oppositely directed one-way inlet and outlet valves in the inlet and outlet arrangement at a first end of each chamber for controlling the flow of a driven fluid into and out of the chamber, oppositely direted inlet and outlet controlled valves in the inlet and outlet arrangement at the second end of each chamber for controlling the flow of a drive fluid into and out of the chamber, a pressure balancing arrangement including a port in each of the controlled valves, an actuator on each controlled valve which is adapted to open and to close the valve and the pressure balancing port in the valve, and a control system which is connected to the actuators of each of the controlled valves for proportionally opening and closing the controlled inlet valves of each chamber in exact opposite phase to each other and for opening and closing the controlled chamb

Abstract: A fluid circulation system in accordance with the invention includes a first fluid utilizing device (12) requiring a minimum fluid flow having an input (14) for receiving the minimum flow and an output (16) for discharging fluid received from the input; a second fluid utilizing device (24) having an input (26) for receiving fluid and an output (31) for outputting fluid; and a valve (80) having a first input (32) for receiving the fluid flow flowing from the output of the second device, a first output (36) for supplying the minimum fluid flow to the first device, a second input (34) for receiving the fluid flow flowing from the output of the first device and a second output (38) for supplying the fluid flow to the second device wherein any deficiency in fluid flow below the first fluid flow flowing from the first input to the first output is supplied with additional fluid flow (102) from the second input to the first output with any remaining fluid flow (104) from the second input flowing from the second outpu

Abstract: A method and an apparatus for regulating a volumetric fuel flow regulate a fuel flow delivered by a feed pump to a high-pressure pump of an injection system as a function of a volumetric fuel discharged from a high-pressure reservoir through a high-pressure regulating valve. The regulation is effected through the use of a pressure regulating valve or a volumetric flow regulating valve.

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: A dual pumping element fluid system for an engine or other system which reduces the driving power consumption by unloading one pumping element through the use of recirculation when a fluid pressure target value is achieved. A cross-over port fluid system prevents cavitation of the unloaded pump. A pressure-activated flow control valve mechanism is utilized to open and close the conduits from the secondary pump. The fluid system works in conjunction with an engine balance shaft system to control gear rattle at low speeds without adding undue gear loads at high speeds.

Abstract: A safety device for avoiding entrapment at a water reservoir drain by using a vacuum operated switch to interrupt power to the reservoir pump and by using a pressure pump to generate a positive pressure to dislodge the obstruction from the drain should a blockage occur. In addition, a manual reset switch requires human intervention to re-activate the reservoir pump once the blockage condition is removed.

Abstract: A tandem pump apparatus is featured having a main suction passage connected to a fluid source. The main suction passage branches into first and second suction passages which, in turn, feed into first and second pumps. Each pump discharges a portion of the fluid to a return passage that is fluidly connected to the suction port of each respective pump. In each return passage, a return control valve is disposed to control the amount of fluid returned to the suction port. The tandem pump featured in this invention exhibits increased efficiency and decreased noise.

Abstract: An oil pump system includes an oil pump, a first hydraulic passage, a second hydraulic passage, a return hydraulic passage, and a control valve. When a revolving speed of a rotor of the oil pump is low, and when a hydraulic pressure of a hydraulic oil, discharged out of a first outlet port of the oil pump to the first hydraulic passage, is lower than a predetermined value, a valve body of the control valve is placed at a first position, thereby joining the hydraulic oil, flowing in the first hydraulic passage, with the hydraulic oil, discharged out of a second outlet port of the oil pump to the second hydraulic passage, and delivering the thus joined hydraulic oil to a hydraulic oil receiving unit via a hydraulic-oil-delivery passage.

Abstract: A fluid transfusing device and method of control therefor includes a plurality of pump driving portions and a microprocessor. Each pump driving portion is for driving a pump, and the microprocessor controls the pump driving portions. The microprocessor executes a fluid transfusing device control program, and interrupts the fluid transfusing device control program upon receiving a pump interrupt. The microprocessor then executes a pump driving interrupt module. When the microprocessor executes the pump driving module, the microprocessor generates a pump driving pulse to control a pump driving portion associated with the pump corresponding to the pump interrupt, determines receipt of another pump interrupt corresponding to a another pump, and generates a pump driving pulse to control a pump driving portion associated with the another pump corresponding to the another pump interrupt.

Abstract: To avoid placing an unnecessary load on a prime mover, a pump control arrangement monitors automotive vehicle speed and inhibits an increase in pump output above a basic estimate when the vehicle speed is below a predetermined level. If the speed falls below the level while the pump output is above the basic estimate, the present operating mode is maintained for a given period before being reduced to the basic estimate level.

Abstract: An automotive air conditioning apparatus includes an input shaft connected to an engine, a pump unit disposed on the input shaft, a compressor unit disposed on the input shaft, and a separator wall disposed between the pump unit and the compressor unit and adapted to seal therebetween in the axial direction of the input shaft. The pump unit includes a first short-circuiting passage communicating the suction space and the discharge space, and the first short-circuiting passage is provided with a first control valve. The compressor unit includes a second short-circuiting passage communicating the suction area and the discharge area, and the second short-circuiting passage is provided with a second control valve. When heating, the first short-circuiting passage is closed with the first control valve, and the second short-circuiting passage is opened with the second control valve to disable the compressor unit.

Abstract: A Roots-type machine is connected to an enclosure to be evacuated via a suction inlet portion, and to a primary pump via a delivery outlet portion. A bellows is disposed transversely in the inlet portion, one end of the bellows being fixed in gastight manner in the wall, and the other end being closed and movable, so that the bellows forms a regulating member for regulating the gas-flow sectional area in the inlet portion. The outside face of the movable end of the bellows is subjected to the pressure in the inlet portion, and the inside face of the movable end is subjected to the pressure in the delivery outlet portion via a rod passing through the wall, and via a channel. The invention applies to Roots-type machines, in particular for automatically regulating the pumping speed so as to match it to the flow-rate of the corresponding primary pump.

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: A constructionally simplified hydraulic pump has two pump elements which discharge from a common suction chamber. The flows can be alternatively fed in common to a pressure outlet or separately to two outlets, one of which outlets leads back into the suction chamber. The pressure-side chambers for the separated flows can be connected, via a unidirectional valve, through which, in the open state, the flow of one pump element can be united with that of the second pump element. The different flow guide modes are switched via control valves whose position depends only on the pressure prevailing at the pressure outlet of the hydraulic pump. The control valves to be switched are a common component of a single control slide valve.

Abstract: An intermediate partition plate is provided between a plurality of adjacent cylinders to partition cylinder chambers in the cylinders from each other. A guide opening portion, in which respective cylinder abutting surfaces are open, is formed in the intermediate partition plate at a position on an outer side than a cylinder circumferential surface, and a slider is housed to be reciprocated. Gas is guided from the cylinder chambers during compression to the guide opening portion through first and second notches to apply the pressures of the cylinder chambers to the slider. A back pressure is applied to the slider from a back pressure pipe to move forward or backward the slider by a difference pressure between the back pressure and the cylinder chamber pressures. The slider shuts off the cylinder chambers from each other or escapes from the first and second notches to cause the cyliner chambers to communicate with each other through the first and second notches and the guide opening portion.

Abstract: A fuel pump having a first pumping mechanism for pumping a fuel in a main tank to a subtank and having a second pumping mechanism for pumping the fuel in the subtank to an outside of the main tank. The fuel pump includes a rotatable impeller having a plurality of outer peripheral vanes, and a wall member surrounding the vanes so as to define a fuel flow passage. The wall member has two partition walls for partitioning the fuel flow passage into a first pumping passage and a second pumping passage, a first suction hole for communicating an upstream end of the first pumping passage to the main tank, a first discharge hole for communicating a downstream end of the first pumping passage to the subtank, a second suction hole for communicating an upstream end of the second pumping passage to the subtank, and a second discharge hole for communicating a downstream end of the second pumping passage out of the main tank.

Abstract: An oil pump includes a pair of pump cartridges, one of which can be unloaded. Oil which is discharged from one of the pump cartridges is supplied to an accumulator through a supply passage in which an orifice is provided. The orifice is opened and closed in response to a pressure which prevails in the accumulator. A spool is operated upon by a pressure differential across the orifice to return the discharged oil to the suction side of the pump. A clearance is formed between the outer surface of the spool and the inner surface of the valve opening in which the spool is fitted, permitting the oil in a chamber into which a pressure prevailing downstream of the orifice is introduced to be returned to the return path.

Abstract: A pneumatic system which in the preferred embodiment includes a pump having a primary suction port and a secondary suction port, with the pump being operable for generating vacuum pressures at both such ports. A first vacuum operated system is coupled to the primary suction port and a second vacuum operated system is coupled to the secondary suction port, and a predetermined, preferably selectively adjustable, orifice is established between the first and second vacuum operated systems for enabling vacuum airflow generated at the first suction port to augment the airflow through the second vacuum operated system. In an alternative embodiment, separate standard vacuum pumps are coupled to the first and second vacuum operated systems.

Abstract: In a compressor having a plurality of banks of cylinders, smaller steps of unloading are achieved by unloading a single cylinder in a bank. When only one cylinder is to be unloaded, gas bypass is used in order to maintain a closer balance of forces in the bank. When the entire bank is unloaded, it is preferably done via the suction cutoff method.

Abstract: An electric motor driven radial piston pump for a motor vehicle brake system with slip control is disclosed wherein the radial piston pump includes two parallel working circuits drivable by the drive motor. The working pressure of the first working circuit is limited to a preset value. Above the preset value only the second working circuit is effective.

Abstract: A multiple channel medication infusion system is disclosed which has a plurality of disposable pump cassettes mounted on a single main pump unit, thereby making the system compact and resulting in an economic system. The system has a printer which may be connected to the main pump unit to provide a printed record of system operation. Several modes are accessible to set up and program the system, to monitor actual system performance, and to test the system or display warnings indicating system malfunctions or that new cassettes should be installed.

Abstract: A common relief valve circuit for controlling or monitoring two or more pumps. The circuit includes two fixed displacement pumps with the pumps being connected to at least two valve bodies or sections that supply fluid to hydraulic cylinders for operating earth-working buckets or the like. A main relief valve is connected to the inlet of a first valve section, and a check valve is connected in a parallel cavity line in the first valve section. The check valve remains closed under conditions where a valve spool in the first valve section is shifted but a valve spool in the second valve section is not shifted or when a valve spool in the second valve section is shifted and a valve spool in the first valve section is not shifted.

Abstract: A volume control for a multi-nozzle rotary pump filling system in which a plurality of rotary pumps are driven from a common drive. Each pump is connected with its own nozzle by way of a connection that includes a volume control operable to adjust the back pressure on the rotary pump to thereby vary the amount of product dispensed by the nozzle. In case of more viscous products, a by-pass line which includes a relief valve is also provided between the inlet side of the control unit and the in-feed side of the pump.

Abstract: A multicylinder rotary compressor has a plurality of cylinders housing rolling pistons which are rotated inside the cylinders by a common crankshaft. Each cylinder has a separate suction pipe. At least one of the suction pipes has a check valve which may be closed to unload the cylinder to which the suction pipe is connected. The check valve has a housing and a slider which can slide inside the housing between an open position and a closed position. The check valve may be closed by introduction of high-pressure refrigerant gas into the space beneath the slider to push it to the closed position when a cylinder is to be unloaded. In another form of the invention, the check valve is closed by a spring made of a shape-memory alloy and a heater for heating the spring above a prescribed temperature at which the allow changes shape. When a cylinder is to be unloaded, the heater is turned on, and the shape-memory alloy deforms into a shape such as to force the slide to the closed position.

Abstract: A multiple cylinder rotary compressor according to the present invention comprises a driving shaft, cylinders concentric to the driving shaft, rotors driven by eccentric portions of the rotary shaft to rotate along the inner circumferential surface of the cylinders, vanes for dividing each of the cylinders into a compression side and a suction side, a partition plate for separating the cylinders from each other, and a control through-hole for connecting the cylinders with each other so that a refrigeration capacity is controlled.

Abstract: A hydraulic arrangement has a housing which includes a first space of a definite first pressure and a second space with a lower second pressure. A primary pump supplies fluid under the first pressure into the first space to open the entrance ports into cylinders, which contain pistons therein, whereby the pistons are forced partially out of the cylinders and into the mentioned second space. In the second space the pistons are moved inwardly into the cylinders by an eccentric cam ring to supply a flow of fluid of a fourth pressure out of the outlet of the arrangement's housing. In modified embodiments the arrangement is a pressure transmission, which takes in a third pressure to drive a motor in the arrangement which in turn drives the shaft with the eccentric cam and the unit then exits the fourth pressure, which might be a very high pressure of up to more than ten thousand pounds per square inch.

Abstract: A vehicle control system has a system part 5 with a pump 6 feeding an open centre valve 4 which controls power assistance for vehicle steering. A second system part 11 has a pump 16 feeding an accumulator 13 and a closed centre valve 10 which controls operation of a clutch or brake booster 2. The pumps 6 and 16 are simultaneously driven by a motor 18. A by-pass valve 21 in conduit 20 is responsive through a pressure transducer 22 and an electrical control unit 19 to pressure in the accumulator 13 so that when the accumulator pressure attains a predetermined value the by-pass valve 21 opens communication between the output from pump 16 and a reservoir 7 to relieve the load on the motor 18. A pressure regulating valve 23 is provided in the steering system part 5.

Abstract: A method of control for load sharing between multiple compressors working in parallel and/or in series which enables all of the load-sharing compressors to carry their optimum share of the load. This load-sharing scheme follows the safest load-sharing formula and also provides for substantial energy savings. It automatically divides the load whenever a strong decoupling between process control and compressors after the compressors' operating points cross their Surge Control lines.

Abstract: A vane type compressor includes a plurality of working chambers defined by the cooperation of a rotor, a plurality of vanes and a cam ring. A valve assembly is disposed in a low pressure passage communicated with the working chambers and operative to bring a portion of the low pressure passage communicated with at least one of the working chambers to a full-closed or full-open position, to thereby effect control of the volume of gas discharged from the compressor.

Abstract: A surge control fluid delivery system is described particularly adapted for pumping of high-viscosity substances from a reservoir for dispensing. The system includes a manifold which is connected to an outlet line of a pump. A vent circuit for returning fluid from the manifold to the reservoir is also provided. Surge control is achieved through a control system which modulates the fluid supply pump and further activates a valve in the vent return line to maintain the pressure of the fluid within the manifold to within adjustable upper and lower limits. The system further includes means for automatically switching from one source of fluid to another upon depletion of the first source.

Abstract: A radial plunger pump is provided for supplying pressurized working fluid to any of a plurality of systems using a simple construction in which the pump housing is provided with a plurality of outlets and a switching device for switchingly supplying pressurized working fluid to the respective systems without a requirement for a pressurized reservoir for the pump.

Abstract: A method and apparatus for operating parallel connected turbocompressors jointly controls their operation such that each operates at the same percentage of its capacity, i.e. such that the spacing of the operating point of each from its blowoff line which is parallel to its pumping limit is the same.