Abstract: An automatic regulating valve apparatus comprises a main valve unit, and a pilot valve unit operatively connected to the main valve unit to control the main valve unit. The main valve unit comprises a main valve casing, a main valve element disposed in the main valve casing, and a main valve driving member disposed in the main valve casing together with the main valve element and having a pressure receiving area greater than that of the main valve element, the main valve element is disposed on the upstream side of a valve seat so as to form a restricting passage between the main valve element and the main valve seat, and the main valve driving member is disposed for sliding movement in a space defined by a cylindrical wall formed in the main valve casing so as to define a main valve driving pressure chamber together with the cylindrical wall.

Abstract: A pilot valve includes a body having a channel formed therein, an inlet chamber formed along the channel, an inlet port in communication with the inlet chamber, a control port in communication with the channel, and a vent port in communication with the channel. A piston is movable within the channel in response to fluid pressure within the inlet chamber. A first spool is movable within the channel and is rigidly secured to the piston to move therewith. A second spool is movable within the channel and carries a vent-valve disc. The second spool also carries an inlet-valve seat which cooperates with an inlet-valve disc carried by the first spool to regulate fluid flow between the inlet chamber and the control port. A vent-valve seat is rigidly secured to the body and cooperates with the vent-disc carried by the second spool to regulate flow between the control port and the vent port. A first spring urges the first spool in a direction opposite pressure in the inlet chamber.

Abstract: A pilot-operated, pressure-loaded, movable diaphragm-type gas-flow regulator valve is shown which is used in flow control applications. A regulator body internal port arrangement interconnects two independent throttling mechanisms in series. Two throttle plates are located within the regulator valve body relative to an inlet chamber and an outlet chamber. A movable diaphragm is positioned relative to a throttle plate by a separate pilot control system to vary the area of throttle plate exposed to flow, and thus, the flow rate of the regulator valve. The throttle plates each have drilled flow apertures which control flow through the valve. Smaller flow apertures are opened before larger flow apertures as the valve diaphragm lifts, thereby ensuring stability at low-flow conditions, while providing high capacity at maximum diaphragm lift.

Abstract: A modulating relief valve comprising a main relief valve and a dome pressure control system. The main relief valve has an inlet subject to system pressure, an outlet, a valve member normally sealing the inlet, a piston that rises and falls wit the valve member, and a dome adjacent to the piston, the dome having a dome pressure. The dome pressure control system is attached to the main relief valve.

Abstract: An automatic-control valve device has a main valve unit, and a pilot valve unit for controlling the main valve unit. The pilot valve unit has a pilot valve A which closes when pressure in a downstream passage on the downstream side of the main valve unit increases beyond a predetermined value, a pilot valve B which opens when pressure in the downstream passage increases beyond the predetermined value. The pilot valve A and the pilot valve B are connected in series by passages through a main valve driving pressure chamber in a section between an upstream passage on the upstream side of the main valve unit and the downstream passage, and cooperate to maintain the pressure in the downstream passage at the predetermined valve.

Abstract: A gas blanket controller, comprising a housing defining a chamber sealed with a diaphragm on a first side of the chamber, and a fitting for a tank outlet on another side of the chamber; a rod secured to the diaphragm for movement with the diaphragm; a rod guide secured to the housing, the rod being guided by the rod guide; weights secured to the rod providing a force resisting movement of the rod; a control linkage secured to the rod; a microswitch mounted on the housing, the microswitch having a toggle that is actuated by the control linkage; a gas blanket supply line; a gas blanket motor control valve on the gas blanket supply line; a communication link between the microswitch and the gas blanket motor control valve; and the rod having a range of motion such that the toggle is operable by contact with the control linkage, whereby the microswitch opens and closes the gas blanket control valve upon operation of the toggle.

Abstract: A pressure reducing valve 30 comprises a body unit 32, a bonnet unit 36, and an operating unit 38 having a handle 126. The pressure reducing valve 30 further comprises a first diaphragm 84, a second diaphragm 86, a third diaphragm 100, and a fourth diaphragm 102 which are provided to extend in the body unit 32 while being separated from each other by predetermined spacing distances, and a nozzle 106 and a flapper 110 which are arranged in a third diaphragm chamber 116.

Abstract: A four-port changeover valve in an emergency water storage tank facility for changing over the flow paths of the water main and to the tank by axially moving the valve rod. Three valve seats are formed axially in a valve box. The valve rod extends through the valve seats. As the four-port changeover valve, the three valve seats can be selectively opened and closed by one and the other of two valve bodies. The water storage tank is connected to a first and a fourth chamber, while the water main is connected to a second and a third chamber. The valve rod is raised and lowered by the cylinder. In a normal state when the water pressure in the water main is at a required level, the valve rod rises so that the tank and the water main communicate with each other.

Abstract: A safety relief valve (10) has a diaphragm actuator (24) including a diaphragm (26) with a dome chamber (34) on one side of the diaphragm (26) and an underdome chamber (36) on an opposed side of the diaphragm (26). A diaphragm operated pilot control valve (38) has a valve body (46) with a pilot sensing port (54), a pilot dome port (64), and a pilot underdome port (60) in fluid communication with a pilot valve chamber (52). A slidable pilot valve member (68) connected to diaphragm (42) is mounted for movement between two pairs of opposed annular seats (80, 84 and 82, 86). Actuation of pilot valve member (68) at a low set pressure permits fluid communication of inlet fluid from pressure vessel (15) to underdome chamber (36) and exhaust of fluid from dome chamber (34) to boost opening of main relief valve member (22).

Abstract: A valve arranged for radial fluid flow from its inlet to its outlet has a spring-loaded diaphragm covering a valve cage member having a central opening communicating with the valve inlet surrounded by a plurality of peripheral openings communicating with the valve outlet. The valve cage member is downwardly concave and a valve top member closing off the valve body has an upwardly concave surface which is substantially the inverse of the concave surface of the valve cage member. Accordingly, the diaphragm moves from a zero flow configuration against the valve cage member to a full flow configuration against the valve top member symmetrically without stretching.

Abstract: A pilot operated safety relief valve (14) has a main piston valve member (60) mounted for reciprocal movement between open and closed positions. The lower end of piston valve member (60) has a seat retainer (87) to retain an annular seat (89) therein. An interchangeable plug (93) is removably connected by bolt (97) to seat retainer (87) and piston valve member (60). Plug (93) extends within the inlet (50) to form a restriction within the inlet (50) defining an angular orifice (99) in the open position of the piston value member (60) for controlling discharge fluid flow. Different size plugs (93, 93A, 93B) as shown in FIG. 4 may be utilized in order to provide the desired orifice size for annular orifice 99 as illustrated in FIG. 4.

Abstract: A pilot operated safety relief valve assembly including a main safety relief valve (14) and a pilot valve (36) connected directly to the relief valve (14) is disclosed. Main safety relief valve (14) has a planar mounting face (76) in contact relation with opposed mating mounting face (78) of the pilot valve (36). Dome ports (72 and 84) in contacting planar faces (76, 78) are in alignment with each other without any tubing therebetween. Exhaust ports (74 and 86) in contacting planar faces (76, 78) are in alignment with each other without any tubing therebetween. Inlet sensing ports (75D, 75E, 65D, 65E) as shown in the embodiments of FIGS. 9 and 10 in contacting planar faces (76D, 76E, 78D, 78E) are in alignment with each other without any tubing therebetween. A fluid pressure pickup fitting (48) has a port (118) which communicates with the fluid passage (50) to the pressure vessel. A test connection (120) is connected to the fluid pressure pickup fitting (48).

Abstract: A pneumatically controlled assembly for the no-bleed regulation of the pressure of a gas as it flows in a pressurized line and including two balance valves that are set to respond to variations in pressure in conjunction with a controller valve so as to effectively regulate and maintain the pressure of the gas in the pressurized line. The balance valves are adjusted to maintain a gas tight seal, to open only in the situation when the gas pressure in the line is over the set amount desired, and to automatically close when the pressure in the line has returned to the desired level. The balance valves act in the situation where the pressure in the line changes, either over or under the set pressure. This is accomplished through a sensor mechanism such as a diaphragm. The diaphragm is set to respond to the desired pressure changes and communicates the pressure changes in the line by means, for example, of deflecting a spring. The sensor communicates the pressure change to one or both balance valves.

Abstract: In a control valve abnormality detection method of detecting abnormality in a control valve, a characteristic expression representing the relationship between three factors in the normal state of the control valve is pre-set. The three factors consist of the displacement of the valve stem, a driving force from the valve stem driving device which changes upon displacement of the valve stem, and the force of the fluid which acts on one end of the valve stem through the valve. The three factors are detected on the basis of measurement result. On the basis of two factors selected from the detected three factors, the estimated value of one factor, which is not selected, is calculated by using the pre-set characteristic expression. The detected value of one factor, which is not selected, is compared with the calculated estimated value, and abnormality in the control valve is determined on the basis of the comparison result. A control valve abnormality detection apparatus is also disclosed.

Abstract: A manifold assembly 10 for operating a safety relief valve 12 includes a manifold block 60 having a block inlet port 230, a block dome pressure port 232, and a pair of control cavities 220 and 222 each adapted for receiving a pilot valve 70 or auxiliary control member 80. Inlet control valves 74, 84, dome pressure control valves 76, 86, and test control valves 78, 88 are each mounted on the manifold block. One of the pilot valves may be maintained on-line for controlling operation of the safety relief valve, while the other pilot valve may be isolated for service. A cartridge pilot valve assembly 70 includes a bushing 126 for facilitating installation and removal of the cartridge valve assembly from the valve block. An improved metal washer 122 is provided having inner and outer knife edges 330, 334 for sealing engagement between the valve body 110 and the block 60.

Abstract: An exhaust reduction system for reducing gas emissions in pipeline controlling devices which operate control valves, which system adjusts and reduces the pressure of a control stream of gas from a conventional line pressure regulator to the control valves. In a preferred embodiment the exhaust reduction system operates in cooperation with the conventional line pressure regulator which reduces the pressure of the gas from the pipeline to a selected system pressure and includes a system high pressure regulator, a system low pressure regulator and in some cases, a selector relay, for further reducing the pressure of the incoming gas and channeling the gas at reduced pressure to at least one controller.

Abstract: A combination pressure vessel and pressure protection installation for the pressure vessel includes a connector pipe connected to the pressure vessel. A valve assembly has a housing block disposed directly on the connector pipe and has at least one safety valve to be hydraulically actuated by a medium brought from the pressure vessel. Lines bring the medium to the safety valve. The lines are guided in segments inside the pressure vessel, the connector pipe and the housing block.

Abstract: A mechanical pressure relief system for a pressurized operating system which is suitable for high purity applications. The pressure relief system utilizes a mechanical logic switch, operable at a set point pressure, in conjunction with a pressurized actuating fluid, completely separated from the processing fluid. The system further utilizes shuttle valves to provide an additional degree of safety, with the minimization of emission of potentially highly hazardous gases, when used in the pressure relief system to prevent further inflow and outflow of processing fluid. Diversion elements are activated, with the pressure logic switch at preselected pressures, for ingress into the system of an actuating fluid. The actuating fluid serves to open venting passageways and to close processing fluid passageways until excessive pressure is relieved. When normal pressure is attained, the pressure logic switch reverses with closing of venting passageways and opening of processing fluid passageways.

Abstract: A vent for relieving pressure from within a storage tank at a predetermined tank pressure through an opening in the tank including a mounting member for connecting the vent in sealed engagement with the opening and for providing a valve opening and associated valve seat, a poppet member for closing the valve seat at tank pressures less than the predetermined tank pressure and for opening the valve seat at tank pressures equal to and greater than the predetermined tank pressure to enable venting of the tank pressure to atmosphere, and an adjusting member for altering the predetermined tank pressure at which the poppet member opens.

Abstract: A testing system for a pilot operated, pressure relief valve of the type wherein movement of the pilot in response to a predetermined line pressure effects the opening of the pressure relief valve comprising a portable apparatus including a source of test fluid pressure, a flow regulating test valve connected to the test pressure source and a piston in the test valve movable in response to the rate of fluid flow through the test valve. The output end of the test valve is connected to a two branch line, one branch line connecting the test valve to the inlet passage of the pilot and the other branch line connecting the test valve to a trapped fluid pressure chamber of the relief valve which is vented by the opening movement of the pilot. A pressure gauge is also connected to the test valve and a plunger on the piston effects the isolation of the pressure gauge when the piston is moved by the increased flow produced through the test valve by the opening of the pilot.

Abstract: The present invention provides a pilot operated pressure reducing valve in which the pilot liquid (generally the pilot fluid) is taken from the low pressure side, wherein two pilot liguid connections (or conduits) from the low pressure side to the pilot valve are provided which the separate from each other. The one connection takes the pilot liquid (or fluid) from the control area of the control spool while the other connection takes the pilot liquid (or fluid) from outside the control range (or area) of the control spool. A check valve is provided to seperate said two connections and closes to the low pressure side. Thus, even for large volume flows and large pressure differentials, between the high pressure side and the low pressure side, good control- and stability characteristics are obtained.

Abstract: The safety device of this invention is made up of a source pressure regulator, an inspirator and a pressure sensing pilot connected to a gas venting means. All of these components are in gas flow connection with each other. The pressure sensing pilot has a valve that will open upon overpressurization of the gas transport system containing these components. Upon this overpressurization the inspirator will cause a vacuum to be formed which will open or activate the gas venting means and permit the excess gas to be vented to the atmosphere.

Abstract: A dome pressure maintaining valve and circuit for maintaining dome fluid pressure in a pilot operated relief valve is presented wherein the dome pressure in the relief valve is prevented from dropping below a preset value even when inlet pressure at the relief valve drops to zero. The dome pressure maintaining valve incorporates a compact check valve and a back flow relief valve with the two components integrated into one piston embodiment, the valve having in communication with a body bore inlet and an outlet. The circuit provides inlet fluid flow in communication with a piston valve chamber through a passage from the inlet port through the piston under the poppet check valve and through multiport and exterior piston valve ring groove means to the outlet port when the inlet fluid pressure is greater than the outlet fluid pressure.

Abstract: A pressure relief valve has a hollow valve body with one or more vent ports in the side wall and a small pilot opening in a first end. A lightweight sleeve, closed at one end, telescopes over the first end of the valve body to close the vent ports. A pressure actuatable element is positioned on the outer surface of the valve body end so as to block the pilot opening therein until the pressure in the valve body exceeds a predetermined value. When the pressure actuatable element unblocks the pilot opening, the interior of the closed end of the sleeve is exposed to the pressure in the valve body, causing the lightweight sleeve to move relative to the valve body to open the vent ports. Suitable pressure actuated elements include a rolling ball or a spring biased closure plate.

Abstract: A pressure control valve has a main valve element of seat type slidably accommodated in a valve case for controlling communication between inlet and outlet sections of the valve case by movement of the main valve element, a control chamber defined within the valve case and between the valve case and an end face of the main valve remote from the outlet section for biasing the main valve element in a valve closing direction, and a variable restriction variable in its opening in response to the movement of the main valve element for communication between the control chamber and the inlet section of the valve case.

Abstract: A main valve includes a product pressure inlet, an outlet, a movable closure member and a pressurized head volume above the closure member. Product pressure relief flow through the main valve is controlled by a modulating, pressure operated pilot relief valve that includes a piston chamber with a reciprocally mounted pilot piston. The chamber is in fluid communication with the pressurized head volume and with the outlet and inlet of the main valve. An inlet valve controls flow from the inlet of the main valve into the chamber and is actuated by the pilot piston. A vent valve is mounted within the piston chamber and controls fluid flow from the piston chamber to the outlet of the main valve and is actuated by the pilot piston.

Abstract: The invention relates to a control system for adjusting the setting of a damper (9) in a ventilation duct (8) and maintaining a substantially constant pressure at a selected region in the ventilation duct, the system comprising a cylinder (1) having a vertical cylinder axis and housing a readily movable, pressure-responsive device (2), which together with the cylinder defines a pressure space. The pressure space (22) communicates with the ventilation duct at the aforementioned selected region, and drive means (11, 12) are provided for adjusting the damper setting in response to the position of the pressure-responsive device, so as to maintain a constant pressure. The inventive system is characterized in that the pressure-sensitive device (2) has a mass which corresponds to a selected pressure at the aforementioned region in the duct and is intended to balance the pressure force acting on the device.

Abstract: There is disclosed a pilot operated valve which includes a valve body, a main valve having a main valve member controlling fluid communication between an inlet port and an outlet port, a pilot valve including a vent passage sensing downstream pressure to open and close the main valve member as the sensed pressure is above or below a predetermined pressure, and selectively operable override means to suspend pilot operation of the valve. The override means may be means to occlude the vent passage and thus close the main valve, means to open the vent passage to atmosphere and thus open the main valve, or means to bypass the main valve.

Abstract: A flow-control valve has a valve housing defining a chamber formed with ally offset source, sump, and user ports. A valve body in the chamber has first and second coaxial but axially independently movable parts, the first part having a mainly axial throughgoing passage having one end exposed continuously to one of the source and sump ports and an opposite axially open end axially sealingly engageable with the second valve part. A central seat between the source and sump ports is axially sealingly engageable with one of the valve parts to isolate one of the source and sump ports from the other of the source and sump ports.

Abstract: This invention relates to a fast response relief valve that includes a housing; a low inertia trigger valve reciprocable with respect to the housing between an open and closed position on a trigger valve seat; and a low inertia relief valve reciprocable with respect to the housing between an open and a closed position on a relief valve seat. The trigger valve seat and the relief valve seat are each a positive stop for their respective valves.

Abstract: A main valve includes a product pressure inlet, an outlet, a movable closure member and a pressurized head volume above the closure member. Product pressure relief flow through the main valve is controlled by a modulating, pressure operated pilot relief valve that includes a piston chamber with a reciprocally mounted pilot piston. The chamber is in fluid communication with the pressurized head volume and with the outlet and inlet of the main valve. An inlet valve controls flow from the inlet of the main valve into the chamber and is actuated by the pilot piston. A vent valve is mounted within the piston chamber and controls fluid flow from the piston chamber to the outlet of the main valve and is actuated by the pilot piston. The pilot piston includes first and second surfaces and effective areas exposed to the pressure in the piston chamber and an end isolated from the piston chamber and in fluid communication with the main valve inlet.

Abstract: A fast opening plug valve especially for release of high pressure gas. The plug has an internal chamber and is held in the closed position by the pressure of gas within this chamber which acts on a fixed wall. The opening stroke is driven by valve inlet pressure upon release of gas from the plug chamber to a dump chamber. Flow from the plug chamber to the dump chamber is choked towards the end of the valve opening cycle to decelerate the plug. Plug acceleration at the start of the opening cycle is commenced prior to opening to minimize the opening period. Release of pressure from the plug chamber may be initiated by action of a slide valve and linked to rise of valve inlet pressure. The valve has application in wind tunnels.

Abstract: The pilot valve 206 disclosed utilizes a piston 226 operating intermediate a pressure setting spring 234 and main valve head volume 222 vent valve, and having a single pressure sensing chamber 235. The operating piston includes an elongated extension 229 of reduced diameter extending from the piston adjacent the sensing chamber and incorporates an opposite end, secondary relief chamber 230 providing main valve operation at pressures fixedly related to the operating piston relief setting. The piston extension operates the vent valve 245 in an adjacent chamber. The piston further defines an internal cavity 240 containing a somewhat coaxial inlet valve 251, 252. Inlet and exhaust valves are in fluid communication through said piston extension. Main valve head volume venting and pressurizing is accomplished through valve body ports cooperating with said inlet and exhaust valves.

Abstract: A fluid control valve for protecting a cryogenic fluid circuit comprising a spring biased plug-type control element that is held closed by a spacer meltalile in the presence of fire.

Abstract: The invention relates to a device for protecting a container containing a pressurized fluid.The device comprises a protection valve and an isolating valve, connected in series and whose opening is controlled by ancillary means, which are sensitive to two pressure thresholds in the container for successively controlling the opening of the isolating valve and then that of the protection valve, when the pressure rises. The isolating valve replaces the protection valve in the case where the latter becomes locked in the open position.Application more particularly to the protection of primary circuits in a pressurized water nuclear reactor.

Abstract: A main valve includes a product pressure inlet, an outlet, a movable closure member and a pressurized head volume above the closure member. Product pressure relief flow through the main valve is controlled by a modulating, pressure operated pilot relief valve that includes a piston chamber with a reciprocally mounted pilot piston. The chamber is in fluid communication with the pressurized head volume and with the outlet and inlet of the main valve. An inlet valve controls flow from the inlet of the main valve into the chamber and is actuated by the pilot piston. A vent valve is mounted within the piston chamber and controls fluid flow from the piston chamber to the outlet of the main valve and is actuated by the pilot piston. The pilot piston includes first and second surfaces and effective areas exposed to the pressure in the piston chamber and an end isolated from the piston chamber and in fluid communication with the main valve inlet.

Abstract: A multi-stage pressure regulating system including a pilot-governed main pressure reducing regulator, with one or more passive back pressure regulators arranged in tandem therewith. The regulators are valves of the type conditioned to open when the upstream pressure therein overcomes a jacket pressure. The jacket in the main valve is loaded by upstream fluid, but a pilot, which monitors a particular fluid flow characteristic, such as pressure, at a selected location in the pipeline, controls bleeding of the jacket as necessary to regulate flow through the main valve so as to maintain a predetermined value or level of the characteristic being monitored. Hence, flow through the main valve is controlled solely by the pilot device, but its discharge to the ultimate downstream level is through at least one auxiliary valve, the jacket of which is loaded with a pneumatic pressure at a suitable level, so that the pressure drop to the downstream level is in two or more stages.

Abstract: The invention relates to a pressure regulating valve for pneumatic and hydraulic pressure media wherein a higher primary pressure is regulated to a desired lower secondary pressure. The valve comprises a primary connection, a secondary connection and a relief connection, there being a switch valve between the primary connection and the secondary connection, a relief valve between the secondary connection and the relief connection, and a control connection for controlling the operation of the valve in response to an external controlled quantity. The controlled quantity may be the secondary pressure output of the valve, or may be another pressure or a mechanical displacement of a larger system.

Abstract: A pilot operated valve is disclosed which may be used, for example, in a refrigerant system to control the flow of refrigerant therethrough. The valve has a pilot operated main valve therein which is selectively actuable by a solenoid. With the pilot valve closed, fluid pressure from the inlet side of the valve acts on the main valve so as to positively hold the main valve closed against a valve seat thereby to block the flow of refrigerant through the valve. The pilot valve member is biased toward its closed position both by a spring and by any fluid pressure within the valve downstream from the valve seat. Fluid pressure upstream from the valve seat acts on the pilot valve member so as to exert an opening force thereon.

Abstract: Disclosed is an in-service test valve and system. The in-service test valve includes a body having a first chamber with a relatively small diameter bore and second chamber axially spaced apart from the first chamber and having a relatively large diameter bore. An imperforate shuttle is slidingly mounted in the valve body and includes a first piston slidingly sealingly mounted in the first chamber bore and a second piston slidingly sealingly mounted in the second chamber bore. An in-service inlet is provided in the valve body for introducing in-service pressure into the first chamber to apply sensing pressure to the first piston and urge the shuttle toward the second chamber. A test inlet is provided for introducing test pressure into the second chamber to apply test pressure to the second piston to urge the shuttle in the direction of the first chamber.

Abstract: A safety valve for walls and other vessels and adapted to vent the vessel to the atmosphere upon the development of a predetermined maximum pressure in the vessel comprises a step plunger carrying a valve member and adapted to displace the valve member toward and away from a seat in a valve housing in which a command chamber is defined between an axial guide for the plunger and an end thereof. The command chamber is controlled by the pressure from the pilot device and the blocks surrounding this axial guide and is connected to the plunger so that the sealing is effected by the bellows and the guide does not need to have a sealing capability.

Abstract: A pressure regulator assembly, suitable for controlling the flow of compressed natural gas to fuel an internal combustion engine, has a small primary valve positioned by a regulator diaphragm to control the flow at high supply pressures and a large secondary valve to provide additional flow area at low supply pressures. Flow to the primary valve passes through a chamber having a restricted aperture from the inlet, and a control diaphragm responsive to the pressure in the chamber opens the secondary valve when the primary valve reaches its maximum flow capacity and the pressure in the chamber approaches the regulated pressure.

Abstract: For use with a safety relief valve, a pilot valve is disclosed. The preferred and illustrated embodiment of the pilot valve incorporates a pressure moved spindle within a housing, the housing being drilled and incorporating a valve and valve seat mechanism. The device is adapted to be connected to a high pressure inlet source. In addition, it has a flow path from the inlet through a needle orifice. This needle orifice chokes the flow into an outlet port. The outlet is provided for controlling a safety relief valve. A third path past the valve element is included which conducts fluid to an exhaust port. A coil spring forms a force in one direction for the valve element while the inlet line pressure forms a force in the opposite direction. When the inlet pressure is sufficiently high, the valve element is moved, thereby opening the valve.

Abstract: In the preferred and illustrated embodiment, a low pressure safety relief valve and pilot for the safety relief valve is particularly adapted for use with steam. The pilot incorporates two diaphragms, one being a sense diaphragm responding to a pressure setting opposed by an adjustable spring, and the second being a boost diaphragm which assists opening of the pilot to a fully open position. The pilot includes an inlet supply passage communicating first through an adjustable and then a fixed orifice to define controllable pressure drops, and forms a control pressure applied to the dome of the safety relief valve. The dome pressure closes a movable piston, subject to differential areas. The safety relief valve is opened by dropping dome pressure at such time as the safety relief valve is controllably opened. The pilot valve, being equipped with a sense diaphragm and selectively boosted by a differential force acting across the boost diaphragm, drops the dome pressure, by venting to atmosphere.

Abstract: A pilot operated relief valve for use on medium and high pressure vessels, conduits and the like.A two-stage, non-flowing valve (5) operates a main relief valve (7) of substantially greater capacity. Flow control elements provided by (35), (36), (38), and (39) associated with the first stage poppet are utilized to provide positive valve operation. In a preferred embodiment the main valve is mounted directly onto the pressure vessel which is to be vented at a predetermined pressure. The pilot is preferably mounted closely adjacent to and in fluid communication with the main valve. A flow adapter (100) having a self-cleaning orifice is disposed intermediate said main valve head volume (68) and pilot vent port (1) to provide improved operation of the combination. A ball (16) selector, (24, 15, 76) provides means for conveniently connecting to a field testing either the pilot or the entire valve, providing improved setpoint and reset or blowdown adjustments for the overall combination.

Abstract: A pilot operated relief valve for use on medium and high pressure vessels, conduits, and the like. A unique two-stage, non-flowing pilot valve operates a main relief valve of substantially greater capacity. In a preferred embodiment main valve is mounted directly onto the pressure vessel which is to be vented at a predetermined pressure. The pilot is preferably mounted closely adjacent to the main valve for operating communication therewith. A particularly unique ball selector provides means for testing both first and second stages without operating the main valve, providing improved setpoint and reset or blowdown adjustments for the overall combination.

Abstract: A pressure responsive pilot valve for a pressure relief valve of the type held closed by system pressure applied to a dome over the valve member. The pilot valve has an inlet port exposed to system pressure, an exhaust port and a control port connected to the dome. Below a set system pressure, the pilot valve interconnects the inlet and control ports to pressurize the dome. At the set pressure, the pilot valve interconnects the control and exhaust ports. The set pressure is adjustable by a sleeve threaded in the body and the blowdown is adjustable by a stem extending through the sleeve.

Abstract: A multifunction hydraulic flow metering valve and a circuit therefore comprising a main valve, a bleed flow orifice, and a servo valve acting with the main valve provides for proportional speed control for lowering loads and as an anti-cavitation check valve. A pilot valve in the circuit acting with the main valve provides the circuit with a pressure limiting relief valve.

Abstract: A pilot operated relief valve for use on medium and high pressure vessels, conduits, and the like.A unique two-stage, non-flowing pilot valve (5) operates a main relief valve (7) of substantially greater capacity. Flow control elements provided by 35, 36, 38, and 39 associated with the first stage poppet are utilized to provide positive valve operation. In a preferred embodiment the main valve is mounted directly onto the pressure vessel which is to be vented at a predetermined pressure. The pilot is preferably mounted closely adjacent to the main valve for operating communication therewith. A ball (16) selector, (24, 15, 76) provides means for conveniently connecting to a field testing either the pilot or the entire valve, providing improved setpoint and reset or blowdown adjustments for the overall combination.

Abstract: A liquid pipeline surge reliever system wherein a main surge relief valve of the expansible tube type is connected into a diverter line from the pipeline. The valve opens when pressure in the diverter line exceeds a jacket control pressure. The jacket is evacuated through a bleed valve, which may be a smaller expansible tube valve but with enough capacity to very rapid evacuation of the main valve jacket. Gas pressure from a suitable source is connected to the main valve jacket whieh, in turn, is connected to both the jacket and the inlet of the bleed valve. Pressure of pipeline liquid in a sensing line opens a pilot valve through which the jacket of the bleed valve is exhausted should the pipeline pressure reach a predetermined surge level. Pipeline pressure at that surge level also closes an on-off valve in the gas supply line while the surge is being relieved.