Abstract: A compressor includes a shell, first and second scroll members, a fitting assembly and a valve assembly. The first scroll member includes a first end plate having a first spiral wrap extending therefrom. The second scroll member includes a second end plate having a second spiral wrap extending therefrom and an injection passage formed in the second end plate. The second spiral wrap is meshingly engaged with the first spiral wrap to form compression pockets. The injection passage is in fluid communication with the compression pockets. The fitting assembly is in fluid communication with the injection passage. The valve assembly coupled to one of the second scroll member and the fitting assembly and movable between a closed position in which fluid communication between the compression pockets and the suction chamber is prevented and an open position in which fluid communication between the compression pockets and the suction chamber is allowed.

Abstract: An overpressure control apparatus is used to control jets of high-pressure fracking fluid or other stimulation fluid released from a treatment flowline in cases of overpressure. The apparatus includes a collection tank and one or more valves, which can all be mounted on or integrated to a skid. The sizes and weights of the collection tank and the skid may help to keep the apparatus on the ground during an overpressure event. The apparatus can be provided with an offline testing system that allows an operator to close off the communication between the apparatus and the treatment flowline, and instead, pump a clean fluid such as water at high-pressure to test the proper functioning of the valve.

Abstract: A valve for pressurized gas or chemical agent. The valve comprises: a body with: an inlet, an outlet, and a passage which connects the inlet with the outlet and which includes a seat]. The valve further comprises a sliding piston able to engage with the seat in order to close the passage and a telescopic extension sliding against the passage in order to guide the piston in the passage at least between the open position and the closed position. The pressure difference between opposite faces of the piston pulls away the piston and the telescopic extension from the seat in order to open the passage, the passage remaining closed under pressure equilibrium. Additionally, a fire extinguishing system.

Abstract: Disclosed are power generation apparatuses. An exemplary power generation apparatus (1) is configured such that water vapor generated in a steam generator (2) is supplied to a scroll expander (3) to drive the scroll expander, wherein: a condensation device (5) is arranged in a discharge path (12) downstream of the scroll expander, the condensation device being configured to mix water vapor having passed through the scroll expander directly with cooling water to condense the water vapor; and the condensation device includes a control unit (10) that performs a control of adjusting the amount of cooling water supply so as to obtain condensed water having a predetermined temperature.

Abstract: A gas discharger connected to a source of pressurized gas comprises a gas channel that is opened to discharge the pressurized gas. A vacuum source can be separately or simultaneously operable with the gas discharger by using the pressurized gas or by using electrical power.

Abstract: The invention relates to a residual pressure valve device comprising a shut-off member (1) that is able to move in the body (9) relative to a seat (2), a return member (5) that urges the shut-off member (1) by default towards the seat (2), the shut-off member (1) comprising an internal duct (6) having a first end in communication with the gas inlet (3) and a second end that leads, via a calibrated orifice (8), into a control chamber (7) that is closed by the shut-off member (1) such that, when the gas pressure in the control chamber (7) reaches a predetermined threshold, this pressure causes the shut-off member (1) to move away from the seat (2), the body of the shut-off member (1) comprising a first portion (11) that forms a male element which is able to move in translation in a female passage of the body (9) with a predetermined fit forming a restriction ensuring partial and progressive opening of the passage for the gas between the inlet (3) and the outlet (4).

Abstract: A gas inlet valve (1) for a compressor (64), comprising: a housing (2); a valve device (6) arranged between a gas inlet portion (3) and a gas outlet portion (4), a valve body (57) resting against a valve seat (56) in a sealing manner when the valve device (6) is in a closed operating state, and the valve body (57) being lifted from the valve seat (56) when the valve device (6) is in an open operating state; a piston device (42) which comprises a first piston portion (43) and a second piston portion (44) which is different from the first piston portion (43), the first piston portion (43) being displaceably guided in a first cylinder portion (22) of the housing (2) and the second piston portion (44) being displaceably guided in a second cylinder portion (27) of the housing (2) which is different from the first cylinder portion (22); and a piston rod (38) which is displaceably mounted in the housing (2) and mechanically couples the valve body (57) of the valve device (6) to the piston rod (38), a fluid line (39)

Abstract: An air gun in combination with a vacuum source is powered by pressurized gas that is received through a gas inlet. The air gun and the vacuum source are configured to be simultaneously operable using the pressurized gas, which provides a method for conveniently air cleaning various objects.

Abstract: A variable displacement compressor for an air conditioning system includes a suction throttle valve. The suction throttle valve includes a housing with a cavity formed therein. A first piston reciprocatingly disposed in the cavity is configured to cause a variable restriction of a flow of refrigerant through a suction inlet formed in the housing. The suction inlet provides fluid communication between a suction port and the cavity formed in the housing. The refrigerant flows through the suction port in a direction that is not parallel to a direction the piston reciprocates within the cavity. The suction throttle valve is configured to increase the restriction in the suction inlet when a crankcase pressure associated with the variable displacement compression is increased relative to an external suction pressure of the refrigerant entering the suction throttle valve.

Abstract: A modulating check valve and method of operating the modulating check valve adapted for mounting to an inlet of a compressor. The modulating check valve includes a flow section through which fluid flow. The flow section has an intake portal and an outlet portal connected to the inlet of the compressor. A flapper valve is disposed in the flow section to prevent backflow from the outlet portal to the intake portal. An actuator controls the flapper valve allowing the flapper valve to open, close and modulate the fluid flow from the intake portal to the outlet portal of the flow section in response to fluid pressure at an outlet of the compressor.

Abstract: The invention relates to a valve (18) for a valve assembly (10) for regulating the pressure of a fluid guided in a hydraulic system for supplying pressure to at least one hydraulic consumer (12a, 12b), comprising a pilot control stage (48) and a main control stage (38) for at least partially clearing or blocking a fluid path from a supply connection (P) to an outflow connection (T), a relief stage (54) for pressure relief of a third chamber arranged between the pilot control stage (48) and the main control stage (38). The relief stage (54) compares the existing load pressure at a load terminal (LS) dedicated to the at least one hydraulic consumer (12a, 12b) with the outflow pressure at the outflow connection (T), clearing the pressure relief if both pressures are approximately the same or identical, which valve is characterized in that the relief stage (54) can be directly connected to the load terminal (LS) and can be charged with load pressure.

Abstract: A spool valve includes a housing having a spring-enclosing portion and a spool-enclosing portion aligned along a longitudinal axis. A spool is mounted for reciprocal axial movement in the housing and a piston is fixed to one end of the spool. The spool-enclosing portion supports a stationary bushing having a bore receiving an opposite control end of the spool, the bushing formed with a first plurality of radially-oriented passages opening into an annular groove formed in the bore, the groove having sloped side edges. The spool supports plural ring-seals arranged to engage the sloped side edges of the annular groove and thereby seal off the radially-oriented passages when the spool is in a neutral position. Movement of the spool is adjustably limited in one direction and dampened in both axial directions.

Abstract: A pressure regulating valve assembly includes a housing. Also included is a valve sleeve mounted within a bore of the housing, the valve sleeve having a first portion and a second portion, the second portion having a diameter less than the first portion and received in a sense piston bore of the housing. Further included is a valve spool mounted within the valve sleeve. Yet further included is a sense piston disposed within the second portion of the valve sleeve. Also included is a damping orifice extending through an end portion of the second portion of the valve sleeve.

Abstract: Disclosed are a method and device for modulating the downstream pressure output of a pressure reducing hydraulic control valve in response to the flow demand fluctuation the method comprising. Included is an adjustable pressure pilot valve mechanism having a drive element extending from the control valve. The drive element is displaceable in response to a flow capacity through the hydraulic control valve. Also included is an adjustable pressure pilot valve deployed along a control tube connecting an upstream pressure port to a downstream pressure port, the adjustable pressure pilot valve associated with the drive element such that adjustable settings of the adjustable pressure pilot valve are responsive to displacement of the drive element.

Abstract: A vapor isolation valve includes a first chamber in fluid communication with a fuel tank and a second chamber disposed with respect to the first chamber. A diaphragm is disposed between the first and second chambers, has an orifice allowing fluid communication therebetween, and is moveable between a diaphragm open position and a diaphragm closed position. A third chamber is disposed adjacent the first chamber, relative to the diaphragm, and is in fluid communication with an exit passage. The diaphragm open position allows fluid communication between the first and third chambers, and the diaphragm closed position substantially restricts fluid communication therebetween. A pilot valve is disposed between the second and third chambers and is selectively moveable between a pilot open position configured to allow fluid communication between the second and third chambers and a pilot closed position configured to block fluid communication therebetween.

Abstract: A gas cylinder valve 2 is able to be opened by application of a pilot gas pressure. In certain embodiments the gas cylinder valve 2 is usable with a yoke 8 for engaging with a valve assembly of a gas cylinder 1, the yoke comprising a pilot gas passage 28 able to connect a pilot gas chamber 37 in the cylinder valve assembly to a source of pressurized pilot gas and the cylinder gas port of the gas cylinder valve to an external cylinder gas passage. The valve and yoke enable the tamper-resistance of a gas cylinder to be improved.

Abstract: A flow controller includes a flow detection unit that includes a detection unit for detecting the flow rate of a fluid; and a flow control unit that is coupled to the flow detection unit and that is capable of adjusting the flow rate of the fluid. The detection sensor constituting the detection unit includes a thermal flow sensor using MEMS technology, and the flow rate of the fluid that has been detected by the detection sensor is output to a control unit. In addition, in the flow control unit, the supply state of air to a supply room is switched by each of a supply-use solenoid valve and an exhaust-use solenoid valve, and on the basis of the supply state of the air, a control valve opens and closes.

Abstract: A fuel return valve and system includes a flow-level select and shut-off valve and a servo control valve. The flow-level select and shut-off valve includes a first fuel inlet, a second fuel inlet, a return-to-tank fuel outlet, and a valve element movable between a shut-off position, a mid-flow position, and a max-flow position. The servo control valve is coupled to the flow-level select and shut-off valve and is configured to control relative fluid pressures therein to selectively move the valve element to the shut-off position, the mid-flow position, and the max-flow position.

Abstract: The invention relates to a sanitary insert part (1) having an insert housing (2), which (2) includes in a housing interior thereof a functional element (3) that controls throughflow and that has at least one throughflow orifice (4). The insert part according to the invention is characterized in that at least one throughflow opening (4) is delimited by a peripheral wall, the shape of which can be changed against a restoring force as a result of the pressure of the inflowing water in such a manner that the at least one throughflow orifice (4) has a variable orifice cross section which can be changed, in dependence on the pressure of the inflowing water, between an open position and a minimized position having a reduced orifice cross section by comparison.

Abstract: Valve module for influencing a fluid supply of a fluid-operated load, comprising a valve housing with a valve chamber being connected to an inlet port and an outlet port and a pilot chamber being connected to an operating port, comprising a valve member which is movably adjustable between a blocking position and a release position and further comprising an actuator which is motion-coupled to the valve member, wherein a position of the actuator and the valve member can be set as a function of a pressure applied to the pilot chamber, and further comprising a sensor device for detecting a position of the valve member and/or the actuator along a movement axis, and the sensor device comprises an electric coil arrangement which forms a ring around at least one fluid port from the group comprising the operating port, the inlet port and the outlet port.

Abstract: An internal pilot type pressure regulator 10 reduces a pressure of compressed air supplied to a primary port 11 and causes it to flow out to a secondary port 12. The pressure of air which flows into the secondary port 12 is set by rotating a handle 61 so as to adjust a spring force which is added to a pilot diaphragm 49. When a bonnet 47, into which the pilot diaphragm 49 and a pressure regulating member 59 are incorporated, is inserted in a pressure regulating adapter 28 and then rotated, an outward projecting portion 71 abuts on an inward projecting portion 73 and is mounted. When a lock member 77 is inserted between the outward projecting portion 71 and the inward projecting portion 73, the pressure regulating adapter 28 is locked.

Abstract: A pneumatically controlled assembly, system, method and device for the regulation of pressure of a gas as it flows in a pressurized line and including at least one loading valve which is set to respond to variations in pressure in conjunction with a pneumatically actuated process control valve so as to effectively regulate and maintain pressure of the gas in the pressurized line.

Abstract: A pilot type pressure regulator has: a primary port to which air is supplied from the outside; and a secondary port discharging air regulated by a main valve body provided to a main valve shaft. A main valve diaphragm abutting on an abutting end surface of the main valve shaft partitions an inner space into a secondary pressure chamber communicating with the secondary port and a pilot pressure chamber to which pilot pressure is supplied. This pressure regulator has an exhaust mechanism exhausting air from the secondary pressure chamber to the outside when pressure of the secondary port exceeds a set value. In the exhaust mechanism, a stopper holding a sealing material in a guide hole is inserted from the side close to a main valve hole, that is, an inner end portion.

Abstract: A fuel metering unit (FMU) comprising a metering valve operable to control the supply of fuel to a delivery chamber of a pressure raising valve (PRV), the PRV including a valve member movable under the influence of the pressure within the delivery chamber between a closed position and an open position in which fuel is able to flow from the delivery chamber to an outlet port, and a push piston movable under the influence of the pressure within a control chamber to urge the valve member towards its open position, wherein the control chamber communicates with a valve control port.

Abstract: An expansion valve (16) for a vapour compression system (1) and a vapour compression system (1) are disclosed. The expansion valve (16) comprises a first valve member (17), a second valve member (20) and a third valve member (21), said valve members (17, 20, 21) being arranged in such a manner that relative movements at least between the first valve member (17) and the second valve member (20), and between the first valve member (17) and the third valve member (21) are possible. The expansion valve (16) is switchable between a first state in which an opening degree of the expansion valve (16) is determined by the relative position of the first valve member (17) and the second valve member (20), and a second state in which an opening degree of the expansion valve (16) is determined by the relative position of the first valve member (17) and the third valve member (21).

Abstract: A pilot valve assembly for regulating the output of a first pressure source relative to a second pressure source, a fluid system equipped with the valve assembly, and a method of operating the valve assembly. The valve assembly includes a valve body with inlet and outlet ports and first and second sensing ports. The first and second sensing ports are adapted to sense, respectively, the fluid pressures of the first and second pressure sources. The inlet port is adapted for fluidically connecting to the first pressure source. The valve assembly defines a flow path between the inlet and outlet ports, and has components for allowing fluid flow from the inlet port, through the flow path, and to the outlet port only if the fluid pressure of the first pressure source exceeds the fluid pressure of the second pressure source by a differential by the flow-allowing components.

Abstract: The present invention relates to an actuator (30) for operating a valve in a fluid line comprising: an actuating member (15) with an actuating element (8) for transferring a force to the device, wherein the actuating member (15) is mounted to move between a first and a second position, a spring (10) for storing energy and for moving the actuating member (15) from its first to its second position by means of this energy in order to thereby move the actuating element (8), lock means for locking the actuating member (15) in its first position, and release means for releasing the actuating member (15) in order to allow the actuating member (15) to move from the first to the second position, wherein the release means are pressure operated and adapted to be in contact with the fluid line and wherein the release means release the actuating member (15) when the pressure in the fluid line exceeds a threshold.

Abstract: A spool valve includes a housing having a spring-enclosing portion and a spool-enclosing portion aligned along a longitudinal axis. A spool is mounted for reciprocal axial movement in the housing and a piston is fixed to one end of the spool. The spool-enclosing portion supports a stationary bushing having a bore receiving an opposite control end of the spool, the bushing formed with a first plurality of radially-oriented passages opening into an annular groove formed in the bore, the groove having sloped side edges. The spool supports plural ring-seals arranged to engage the sloped side edges of the annular groove and thereby seal off the radially-oriented passages when the spool is in a neutral position. Movement of the spool is adjustably limited in one direction and dampened in both axial directions.

Abstract: A system for hydraulically managing fluid pressure between selected set points includes a pilot control system operably coupled to a main valve. The pilot control system includes at least one fluid conduit, a variable orifice assembly, and a control pilot valve apparatus. Fluid is passed through a fixed orifice and into a first chamber of the control pilot valve apparatus. Fluid is passed through the variable orifice of the variable orifice assembly and into a second chamber of the control pilot valve apparatus. The main valve is hydraulically opened or closed in response to a pressure differential between the first and second chambers of the control pilot valve apparatus so as to manage fluid pressure downstream of the main valve between the selected upper and lower set points.

Abstract: A control valve for an air cushion bed includes a first main body, a membrane plate, a second main body, a sensor, and a depressurization unit. The membrane plate is clamped between the first main body and the second main body. The second main body at one side of the membrane plate is connected with the sensor. The sensor is used to detect the inputted air pressure. When the air is over, the air can be depressurized by the depressurization unit. The control valve of the present invention is applied to input and control the air of the air cushion bed, having depressurization and air detection functions.

Abstract: A flush valve for a waste water system includes a valve body and a vent system. The valve includes a fluid inlet, a fluid outlet and a main valve element extending therebetween and adapted for movement to allow fluid flow therethrough based on a pressure differential across a portion of the main valve element. The vent system includes a control chamber, in flow communication with the fluid inlet of the valve and a vent outlet in flow communication with the fluid outlet of the valve. The flush valve further includes a relief system including a relief chamber with a relief inlet in flow communication with the control chamber and a relief outlet in flow communication with the vent outlet. A mechanical relief device is configured to open and close the relief inlet based on a predetermined fluid pressure at the relief inlet, thereby venting fluid from the control chamber to the vent outlet.

Abstract: A multifunction relief valve includes a relief chamber having an introduction port and a relief port for introducing and relieving pressure fluid; a back pressure chamber formed on one end side of the relief chamber; a piston which is movably provided in the back pressure chamber and divides the back pressure chamber into a first back pressure chamber and a second back pressure chamber; a first spring which is provided in the first back pressure chamber and exerts a biasing force in a direction in which the relief port is closed; a second spring which is provided in the second back pressure chamber and biases the piston in the direction in which the relief port is closed; and a pilot pressure supply port formed in the first back pressure chamber. The pressure fluid introduced into the first back pressure chamber via the pilot pressure supply port changes the relief pressure.

Abstract: A spool valve is formed from a spool having two adjacent lands of equal cross-sectional dimensions, and a third land having greater cross-sectional dimensions than the other two. The spool reciprocably moves through a bore formed in a housing, so as to open and close fluid communication between selected pairs of ports formed in the housing. The bore includes a first chamber which receives the third land of the spool and has no externally communicating port formed in its walls. The spool valve may be used as a control valve for the actuator of a system valve. As the spool valve begins to actuate, the third land becomes exposed to actuator pressure. The greater area of the third land serves to increase the force applied to the spool valve by the actuator pressure source, enhancing protection from unintended or malicious resetting of the spool.

Abstract: The present invention relates to an oil control valve for a variable valve lift system that obtains in a stable manner a constant hydraulic pressure in the hydraulic line connecting the oil control valve and the vale lift control actuator, and thereby reliably controls valve lift according to the number of revolutions and load of the engine.

Abstract: An adjustable hydraulically operated pressure management control pilot assembly has first and second diaphragm assemblies which define two fluid pressure chambers. Varying the pressure between these two fluid chambers modulates the control pilot assembly between adjusted low and high set points, which can be used to control high and low pressures downstream of a pressure reducing valve of a water supply system.

Abstract: A pressure control valve is provided, which can variably control the set pressure of a relief valve in accordance with pilot signal pressure that is controlled in an operator's seat and so on when the set pressure of the relief valve required in a replaced working device is changed.

Abstract: A pressure limiting valve has a control element (10) which can be acted on in an opening direction, against a first control face, by a pressure which is to be limited, and which can be acted on in a closing direction by a spring (16) and, against a second control face, by a control pressure prevailing in a control pressure space (14). The pressure prevailing in the control pressure space can be limited by means of a pilot control valve (21). A control fluid can be supplied to the control pressure space through the control element via a control fluid nozzle (48). Upstream of the first control face, a plate (38) is held on the control element. Formed between the plate and the first control face is a gap with a predefined gap dimension. Said gap is situated upstream of the control fluid nozzle.

Abstract: Embodiments of a valve actuator are provided for adjusting the position of a main valve element in relation to the pressure of a fluid supplied by a supply duct. The valve actuator includes a housing, a control pressure valve disposed in the housing, and a piston slidably disposed in the housing and mechanically coupled to the main valve element. The housing has a control pressure chamber therein, which is configured to be fluidly coupled to the supply duct. The control pressure valve is configured to substantially impede fluid flow into the control pressure chamber until the fluid pressure within the supply duct surpasses a minimum actuation pressure. The piston normally resides in a first position and is configured to move toward a second position as the pressure within the control pressure chamber increases.

Abstract: Disclosed herein is a switching valve for transmitting of fluids. In particular, disclosed herein is a switching valve for filling of gas tanks having a housing with an inlet area and an outlet portion. A check valve, a vent valve, and an inlet valve can be disposed within the housing. The vent valve and the inlet valve can be controlled by a slide that is coupled with a pivoting lever which is actuated by a control valve in a pressure controlled manner.

Abstract: A pressure regulator is provided. In one embodiment, the pressure regulator includes a piston and supply seal rings, wherein the diameter of the piston is at least half of the sum of the diameters of the supply seal rings to reduce deadband and increase sensitivity. In another embodiment, the pressure regulator has a maximum deadband of less than 200 pounds per square inch when coupled to a supply pressure of at least 1000 pounds per square inch. Other embodiments related to pressure regulators are also provided.

Abstract: A relief system for process fluids under pressure. The system includes a normally open isolation valve in fluid communication with a process system under pressure through an upstream conduit. A buckling pin actuator is in fluid communication with the upstream conduit through a sensing line. A spring activated actuator is engaged with the isolation relief valve in order to retain the isolation valve in a closed position. A buckling actuator bypass valve is supplied with non process fluid pressure to an input port and the buckling actuator bypass valve also includes a first output port to the spring activated actuator and a second output port to a vent whereby pressure in the process system above a predetermined level will actuate the buckling pin actuator, moving said buckling actuator bypass valve to said second outlet port to vent and thereby moving the spring activated actuator in order to open the isolation valve.

Abstract: A flow controller includes a flow detection unit that includes a detection unit for detecting the flow rate of a fluid; and a flow control unit that is coupled to the flow detection unit and that is capable of adjusting the flow rate of the fluid. The detection sensor constituting the detection unit includes a thermal flow sensor using MEMS technology, and the flow rate of the fluid that has been detected by the detection sensor is output to a control unit. In addition, in the flow control unit, the supply state of air to a supply room is switched by each of a supply-use solenoid valve and an exhaust-use solenoid valve, and on the basis of the supply state of the air, a control valve opens and closes.

Abstract: A centralized automatic fluid or gas spill prevention and shut-off valve system that prevents line ruptures comprising means to reduce fluid pressures, such as gas, to appropriate levels, a continuous monitoring of downstream conditions, an immediate stop system of major spillage caused by excessive flow wherein said immediate stop system automatically shuts off the flow of fluids, means for timed shut off of minor fluid flows that exceed a predetermined amount of time and a restarting system that restarts when overflow conditions are corrected, wherein said restarting system works automatically or manually.

Abstract: A solenoid valve for controlling a fluid has a first housing part (2), an axial guide (3), facing inwards, for an armature (4) which can be displaced in the axial guide (3) under the effect of a solenoid (5) that at least partially surrounds the exterior of the first housing part (2), a return spring (6) and a closing element (27) impacting a valve closing element (7), and a second housing part (9) which is arranged coaxially to the first housing part (2). The solenoid valve according to the invention is characterized in that the first housing part (2) has a reduced wall portion (17) which faces inwards towards the armature (4) and the second housing part (9) and which effects a magnetic separation of the two housing parts (2, 9) to at least some extent.

Abstract: A regulator valve includes a duct, a valve element, and an actuator. The duct has an inner surface defining a flow passage. The valve element is movably disposed within the flow passage between an open position, in which fluid is permitted to flow through the flow passage, and a closed position, in which fluid is restricted from flowing through the flow passage. The actuator is coupled to the valve element and at least facilitates movement thereof between the closed and open positions and locking of the valve element in an intermediate position therebetween. The actuator comprises a shaft and a locking system. The shaft is coupled to the valve element and moves therewith. The locking system is coupled to the shaft and is activated when the valve element is in the intermediate position, to thereby at least inhibit movement of the shaft and the valve element.

Abstract: A vacuum control system using a vacuum pump to control a vacuum pressure and a flow of a processing gas in a vacuum chamber. The vacuum control system includes: a plurality of vacuum control valves, each of the valves being connected between each of a plurality of gas discharge ports and the vacuum pump; a pressure measurement unit configured to measure the vacuum pressure of the processing gas supplied to the object; and a controller configured to manipulate respective openings of the valves in accordance with the measured vacuum pressure.

Abstract: A pilot valve assembly for regulating the output of a first pressure source relative to a second pressure source, a fluid system equipped with the valve assembly, and a method of operating the valve assembly. The valve assembly includes a valve body with inlet and outlet ports and first and second sensing ports. The first and second sensing ports are adapted to sense, respectively, the fluid pressures of the first and second pressure sources. The inlet port is adapted for fluidically connecting to the first pressure source. The valve assembly defines a flow path between the inlet and outlet ports, and has components for allowing fluid flow from the inlet port, through the flow path, and to the outlet port only if the fluid pressure of the first pressure source exceeds the fluid pressure of the second pressure source by a differential by the flow-allowing components.

Abstract: A system for controlling the pressure output of an engine-driven centrifugal fire pump includes a discharge pressure sensor mounted in the discharge line of the pump. A governor varies the rpms of the engine in response to pressure changes detected by the discharge pressure sensor. If the pressure in the system is higher than the desired output pressure when the engine is running at its idle speed an electronically controlled hydraulic relief valve responsive to the discharge pressure sensor operates to relieve the excess pressure in over pressure situations. If the pressure in the system is lower than the desired output pressure when the relief valve is fully closed, the engine speed is increased.

Abstract: A multi-mode pressure relief valve includes a body having fluid inlet and outlet ports and a compressed gas inlet port. The fluid ports and gas port isolated from one another. A reciprocating piston is in communication with the gas port. A valve stem is movable between an open condition and a closed position to permit and stop flow communication between the fluid ports. A spring is disposed between the valve stem and the piston and urges the piston and valve stem away from one another.

Abstract: An air gun in combination with a vacuum source is powered by pressurized gas that is received through a gas inlet. The air gun and the vacuum source are configured to be simultaneously operable using the pressurized gas, which provides a method for conveniently air cleaning various objects.