Abstract: An apparatus and method for regulating the pressure of fluid flowing though a conduit system according to which a valve seat is formed in a lower housing connecting in the conduit system with the seat extending between an upstream portion of the system and a downstream portion of the system. A valve stem is mounted in the lower housing for axial movement in the lower housing and one end of the stem is connected to a valve head. Two spaced membranes are mounted in the upper housing to define two chambers, and the membranes are connected to the valve stem . The downstream portion of the conduit system is connected to one of the chambers to apply a load to of the membranes in proportion to the fluid pressure in the downstream portion so that changes in the fluid pressure in the downstream portion causes corresponding changes to the load on the one membrane, corresponding movement of the valve stem and the valve head, and corresponding changes to the fluid flow through the lower housing.

Abstract: The present invention provides a method, apparatus and system for using sacrificial buckling pin technology for a reliable actuated safety relief valve and for a pilot valve system. The buckling pin fails at a predicted, predetermined system pressure through transfer of force exerted by the system pressure on a sensing piston or diaphragm to the buckling pin. The buckling pin failure triggers the release of a latch mechanism that releases the actuator assembly to slide away from the valve seat to initiate relief flow. The use of the buckling pin as a trigger for release of a latch provides for valves with high flow rates without the use of large, unmanageable buckling pins. The use of a buckling pin valve as a pilot valve to control a single or multiple relief valves operating together as a pressure relief system is preferred as particularly advantageous.

Abstract: A proportional control gas valve includes a valve body formed with an inlet having a first orifice, a first chamber communication with the inlet through the orifice, a second chamber formed with a balancing orifice and a second orifice, a third chamber in communication with the first chamber through the balancing orifice, a fourth chamber in communication with the first chamber via the second orifice, a fifth chamber in communication with the fourth chamber, and an outlet in communication with the fifth chamber, a solenoid assembly mounted in the first chamber for controlling gas flowing from the first chamber to the fourth chamber via the second orifice, a main diaphragm arranged between the inlet and the third chamber, a valve spring mounted under the main diaphragm and urging the main diaphragm to move upwardly to close a passage from the inlet to the outlet, a regulation diaphragm mounted inside the fifth chamber, a regulation spring mounted on the regulation diaphragm, an adjust stem connected with the r

Abstract: An improved slow opening gas valve providing for continuous gradual and smooth opening of the gas valve includes an expansible auxiliary chamber connected to an expansible control chamber by a metering orifice. The expansible auxiliary chamber slows expansion of the expansible control chamber, thereby slowing opening of the gas valve and allowing gas to ignite at a lower pressure with a much less audible sound. The gas valve is provided with a normally closed valve member for controlling flow of gas through the gas valve and a diaphragm forms a movable wall of the expansible control chamber that is operable upon expansion of the chamber to move the valve member to an open position. The expansible auxiliary chamber also comprises a movable diaphragm to control the opening of the gas valve and provide gas flow gradually and smoothly.

Abstract: A valve assembly for a hydraulic discharge device and including a piston displaceable in a bore of a housing of the discharge device against a biasing force and having an outer surface, which sealingly engages an inner wall of the housing bore and blocks a channel opening into the bore so that the piston functions as a slide valve for this channel, the valve assembly further including a valve seat which, together with the piston, forms a seated valve.

Abstract: The diaphragm regulator controls fluid pressure in downstream piping. The regulator may also be used as an on/off valve, although this is not its primary application. A central circular housing in the body of the regulator receives a removable flow diffuser to reduce turbulence when fluid is flowing from the inlet port to the outlet port of the regulator. The flow diffuser has a flat circular base with an inlet zone in the center and a plurality of vanes extending from the inlet zone to the outer circumference of the base. These vanes are spaced apart and define a plurality of flow passageways permitting fluid to flow from the inlet port, through the inlet zone, through the passageways, through the transition zone and exit the outlet port. Each vane has a flat upper surface parallel with the base and an inclined surface sloping downward from the flat upper surface to the inlet zone.

Abstract: A pressure relief system includes a relief valve for selectively discharging process media from a pressure vessel, a pilot valve for controlling the relief valve, and an isolation system for isolating the pilot valve from the process media. The pilot valve has an inlet port, a control port in communication with a dome chamber of the relief valve, and a discharge port. The isolation system includes an accumulator such as a piston-type or bladder-type accumulator, a source of pressurized control fluid, a pressure regulator, and a check valve. The accumulator has an interior chamber with an inlet in communication with an inlet of the relief valve and an outlet in communication with the inlet port of the pilot valve. An isolator such as a piston or bladder divides the interior chamber into a first portion and a second portion and prevents flow therebetween to isolate process media (located in the first portion) from control fluid (located in the second portion).

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 2-way fitted valve (2) includes a main piston (6) guided in a valve bush (4) and allowing flow of a hydraulic fluid therethrough, whereby an inlet port (B) is connected with an outlet port (A). In the region of a throttle point (8) of the main piston (6) an effective surface (D-d) is provided, so that due to the pressure drop at the throttle point (8) a pressure force acts on the main piston (6) such as to urge it in the direction towards its home position.

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 valve unit comprises a single electromagnetic actuator for controlling both an ON-OFF valve for cutting off the gas and a modulation valve; the latter is subject to independent resilient loads for regulating the minimum pressure delivered and for regulating the pressure up to the maximum pressure at the modulation stage.

Abstract: The invention provides a pilot valve apparatus for use in an automatic fluid control system for maintaining pressure downstream from a main control valve between two setpoints irrespective of flow changes through the main control valve. The pilot valve has a flexible pilot diaphragm which moves with a moveable pilot valve member to cooperate with a fixed pilot valve member to control fluid flow through the pilot valve apparatus. The pilot valve controls control pressure acting on the main control valve. An actuator apparatus connected to a body of the pilot valve apparatus has a moveable actuator partition which is exposed to a pressure differential signal reflecting flow through the main control valve. A resilient connector cooperates with the actuator partition and the pilot diaphragm to permit limited relative movement therebetween, and to transfer resilient force to the pilot diaphragm resulting from movement of the actuator partition.

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: The blanketing valve has a diagnostic port to aid in analyzing the valve's operation. A pressure gauge is connectable or permanently connected to the diagnostic port. The diagnostic port measures the pressure above a main valve in a passageway connecting a pilot inlet chamber and a main valve piston chamber. This pressure controls the main valve and is an indicator of pilot valve action. Comparing this pressure to inlet pressure indicates pilot response and is a valuable aid in determining what problems may exist.

Abstract: A two-port cartridge type seat valve has a valve sleeve with a stepped guide bore for a poppet. The poppet includes a piston flange that divides the second step of the guide bore axially into an end-face first pilot chamber and an annular second pilot chamber. A first connection channel through the valve sleeve connects the annular second pilot chamber with an annular chamber into which a lateral main flow port opens. The free cross-section of a valve seat and of an axial main flow bore correspond approximately to the cross-section of the first step of the guide bore.

Abstract: A diaphragm/spring operated pressure relief valve having a sensing passage of substantially the same flow area as the outlet orifice of the valve whereby failure of either diaphragm results in "fail open" configuration. In addition the effective area of the balancing diaphragm is substantially the same as the seat area of the seat seal of the outlet orifice such that a pressure or vacuum on the valve outlet pushes or pulls equally on the balancing diaphragm and the valve seat seal thereby balancing the forces and keeping the valve stable.

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: The blanketing valve has a diagnostic port to aid in analyzing the valve's operation. A pressure gauge is connectable or permanently connected to the diagnostic port. The diagnostic port measures the pressure above a main valve in a passageway connecting a pilot inlet chamber and a main valve piston chamber. This pressure controls the main valve and is an indicator of pilot valve action. Comparing this pressure to inlet pressure indicates pilot response and is a valuable aid in determining what problems may exist.

Abstract: A pressure unloading pilot operated fluid pressure regulator having a throttling element for controlling fluid flow. A pilot amplifier senses regulator outlet pressure and supplies suitable loading pressure coupled from an inlet supply pressure line through a variable flow restrictor to the throttling element. A check valve has a preset differential pressure defined between the check valve inlet and outlet and is mounted in parallel flow with the flow restrictor to limit the maximum differential pressure across the throttling element to the preset differential pressure of the check valve.

Abstract: A tank blanketing system protects both the tank vapor space and the environment. A pad valve supplies inert gas to the vapor space and maintains the pressure in the vapor space under conditions that tend to reduce the pressure in the vapor space. Should the pressure rise a predetermined amount above the setting of the pad valve, a depad valve will open to vent vapors so as to return the pressure in the vapor space to its designed operating range. The depad valve is connected to a recovery piping system that will route the vapors to an appropriate device that processes or disposes of them in a predetermined manner.

Abstract: A metering valve includes a main valve and a pilot valve for operating the main valve. A low operating force pawl and ratchet system rotates a cam to open the pilot valve to initiate a cycle of operation. When the main valve is opened, a turbine wheel in the flow path rotates to measure flow. Turbine rotation is transmitted to the cam through a reducing gear assembly and a lost motion connection in order to reclose the pilot and main valves after a predetermined volume of flow is measured.

Abstract: An apparatus free of polymer material in contact with process gas for delivering process gas for making semiconductors includes a pressure regulator for regulating the pressure of the process gas to be delivered by the apparatus from a supply of pressurized process gas. The pressure regulator has a first valve seat and a first valve which cooperates with the first valve seat for controlling the flow of process gas through the regulator. Both the first valve seat and the first valve are formed of metal. The apparatus further includes a second valve having metal-to-metal dynamic seating for controlling the flow of the gas from the supply to the regulator. The second valve is provided immediately upstream of the pressure regulator along a flow path for the gas through the apparatus. A relatively high creep of the pressure regulator is significantly reduced by operating the regulator in conjunction with the pneumatically operated (on/off) second valve.

Abstract: A pressure compensation valve is constructed with a valve establishing and blocking a communication between an inlet port and an outlet port, a pressure receiving chamber, a piston driven by a load pressure within the pressure receiving chamber and shifting the valve in blocking direction, an intermediate pressure receiving chamber communicated with the inlet port via a first conduit and pushing the valve in blocking direction by the pressure therein, and a pressure variable relief valve for relieving a pressurized fluid in the intermediate pressure chamber to the outlet port via a second conduit.

Abstract: A servovalve includes a casing presenting an inlet and an outlet, and a primary valve supported on the casing and including a valve plug that is movable between a closed position blocking flow through the casing, and a plurality of open positions in which the valve plug presents a restriction of variable size for varying the flow. A diaphragm supports the valve plug and includes a first side proximal to the plug and a second side remote from the plug. A control chamber is provided on the first side of the diaphragm, and is connected to the inlet by a pilot inlet passage and to the outlet by a pilot outlet passage. A pilot valve controls the flow of fluid through the pilot outlet passage, and includes a control plug that is movable between a closed position in which the control plug blocks the pilot outlet passage, and a plurality of open positions in which the control plug presents a restriction of variable size within the pilot outlet passage for varying the flow between the control chamber and the outlet.

Abstract: The device for inflating pneumatic tires comprises an inlet of pressurized air and an outlet for sending the air into a pneumatic tire. A first circuit of the device is divided into an initial tract and a final tract, which connects the inlet with the outlet, passing through a first on-off valve provided with a membrane. A second circuit of the device connects the inlet with a first chamber of the first on-off valve. The first chamber is also connected to a pressure regulator connected at outlet to a second on-off valve, which intercepts the air flow. A third circuit connects the outlet to a first chamber of the second on-off valve.

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: A safety relief valve (10) having a main valve member (22) in a normally closed seated position has a diaphragm actuator (24) with a dome chamber (34) adjacent the outer side of the diaphragm (26). A pilot valve (28) is in fluid communication with the dome chamber (34) through a dome line (35) for controlling the opening and closing of the main valve member (22). An underdome chamber (40) on the inner side of the diaphragm (26) has an underdome line 44 extending to an underdome control valve (42) for controlling fluid communication to underdome chamber (40) from the inlet (18). An inlet line (48) extends from the inlet (18) to the underdome control valve (42). When the set pressure of the pilot valve (28) is reached, inlet fluid pressure on the inner side of the diaphragm (26) increases while dome pressure in the dome chamber (34) decreases.

Abstract: A pressure control valve having a housing with a main inlet passage and a bypass outlet passage. A combined control is located in the housing to control the flow of fluid from the main inlet passage to the bypass outlet passage. The combined control includes a chamber in the housing having an inlet connected to the main inlet passage, an outlet connected to the bypass outlet opening and a loading opening. A poppet is located in the chamber and is movable between a first position closing the inlet and a second position opening the inlet to allow fluid to flow from the main inlet passage to the bypass outlet passage. A spool is positioned within the poppet and is movable between an open position allowing fluid to flow between the main inlet passage and the bypass outlet passage. A spring biases the spool toward the closed position. A connecting passage is located in the housing to connect the main inlet passage to the loading opening.

Abstract: A tank vent valve for use with a pilot valve that comprises a vent valve body containing a nozzle, a seat plate movable within said vent valve body which seats on said nozzle to seal the valve, and an articulated stem extending from the center of said seat plate and a diaphragm actuator mounted on said vent valve body comprising a resilient member, a support plate below said resilient member and a hollow member attached to said support plate extending toward said seat plate and surrounding said stem, said stem being slidably movable within said hollow member, the upper surface of said diaphragm being in fluid communication with the pressure in said tank through a pilot valve. The stem is terminated in a ball and socket arrangement so that the valve will still seat if the stem is slightly misaligned.

Abstract: A pilot stage for pressure control valves includes an axially displaceable valve piston which bounds a valve chamber axially on one side and includes a valve seat for a closure cone therein. Valve piston has an actuating surface in a pressure chamber that is substantially larger than the free cross section of the valve seat. By pressurization of this pressure chamber, a large hydrostatic force is exerted on the valve piston which opposes the closing force of the pressure-setting spring. A housing stop fixes a first axial end position of the valve piston in the direction of this hydrostatic force. The pilot control stage has improved properties for both manually adjustable pressure control valves and proportional pressure control valves.

Abstract: A pilot actuator and a pilot actuated tank vent valve that comprises: (a) a vent valve body having a pallet which seats on a nozzle to seal the valve; (b) a pallet actuator mounted on the vent valve body and mechanically linked to the pallet, the upper surface of the pallet actuator being in fluid communication with the pressure in the tank through; (c) a pilot valve mounted on the diaphragm actuator and having (1) a spring loaded sensing actuator, (2) a spindle connected to and operated by the sensing actuator, (3) an inlet port in fluid communication with the pressure in the tank, (4) a first passageway for communicating the pressure from the inlet port to the pallet actuator (5) a second passageway for communicating the pressure from the inlet port to the under side of the sensing actuator and (6) a seating mechanism connected to the spindle for sealing an opening between the first passageway and an outlet port, the first passageway being offset from the inlet port and preferably laterally to the second pa

Abstract: A convertible two-stage pressure regulator in which a main valve regulates fluid flow between an inlet and outlet in response to a control pressure produced by a servo regulator valve, the control pressure depending on outlet pressure and the force provided by a regulator spring to a diaphragm carrying a servo regulator valve closure element. Compression of the regulator spring is controlled by a solenoid armature in a plunger assembly which is selectively positionable by a selector knob to obtain higher or lower regulator spring force. Adjustable stops provide for individual adjustment of low and high outlet pressures for each of two pressure ranges. Substantially identical air gaps in the magnetic circuit of the solenoid are provided for both pressure ranges by a magnetic pole piece in the plunger assembly which extends beyond the solenoid coil in one direction and a solenoid armature which extends beyond the solenoid coil in the opposite direction.

Abstract: A system, device, regulator and process for gas blanketing under precise gas pressure control is provided herein exhibiting extreme pressure sensitivity, position flexibility, smooth gas shutoff, for regulating the pressure of liquid storage vessels having vapor phases therein, and optionally being useful for gas blanketing of other units requiring positive gas pressures therein, such as pressurized rooms, duct, housings, such as computer housing, and the like, at pre-selected pressures of between 0.01 inches of water column and 15 inches of water column, with pressure sensitivities responsive to pressure changes of 0.01 inches of water column within a predetermined pressure set point. The system is compact, self contained, and requires no external source of power other than the supply pressure, which can range from about 10 psig to 1,000 psig. The system, device and regulator are not position sensitive, and may be properly operated in any orientation.

Abstract: A convertible two-stage pressure regulator in which a main valve regulates fluid flow between an inlet and an outlet in response to a control pressure produced by first and second regulator valves arranged in parallel, the control pressure depending on the outlet pressure and the forces applied by compression springs to diaphragms carrying the first and second regulator valve closure elements. An electrically operated valve is provided for selectively disabling the second regulator valve whose regulator spring applies a higher force than the spring of the first regulator valve. The compressions of the regulator valve springs are coordinately varied by a manually operable selector mechanism for convening between natural and LP gas usages.

Abstract: An isolation automatic control valve is formed by disposing an isolation valve of very simple structure in the inlet and outlet passages of a main valve or in the passage joining a main valve and its pilot valve, which not only controls normal operation during automatic controlling but also can isolate the main valve from the pilot valve for on-line maintenance while simultaneously controlling operation of the main valve manually or automatically. The isolation valve includes a throttling function to enable the main valve to acquire various control parameters. The present invention enumerates nine embodiments of different pressure, flow and direction control valves, each being applicable in various fields of general purpose valves, hydropneumatic valves and instrument valves. The present invention exhibits compact structure, simple piping, adjustable parameters and convenience in operation.

Abstract: An automatic control valve has a main valve member moveable between open and closed positions thereof in response to pressure applied to a first piston or diaphragm in a first control chamber. The valve member moves to modulate flow through the valve to maintain desired flow conditions. Pilot pressure signals are generated to reflect the flow conditions, usually upstream and downstream from the valve, which signals are processed to generate a control signal which is fed to the first control chamber to control pressure therein. Normal movement of the valve produces wear which causes leakage of the diaphragm or seals oft he piston causing loss of primary control of the valve member which tends to fail "open". This causes an initial rise in flow through the valve which is detected by the pilot pressure signal but because of the leakage, is unable to correct.

Abstract: An electrically controlled modulating pressure regulator in which a main valve regulates fluid flow between an inlet and an outlet in response to a control pressure produced by a servo valve which is responsive to the outlet pressure and the force applied by a regulator spring to a diaphragm carrying the servo valve closure element. Deformation of the regulator spring can be varied by an electrical actuator in the form of a wire segment of a shape memory alloy through which electric current can be passed to vary its temperature and length.

Abstract: A fluid pressure relief system and method for a pressure vessel or tank (10) having a normal vent (16) with a first pilot operated safety valve (18) and an emergency vent (62) having a second pilot operated safety valve (25). A vapor recovery line (20) is connected to relief valve (18) and collected at a vapor storage container (21). A manway (22) on the pressure vessel (10) shown in FIG. 2 defines the emergency vent (62) and a main valve member (66) has a counterweight (74) thereon to urge main valve member (66) to a seated closed position on nozzle (60). The first pilot operated safety valve (18) for the normal vent (16) is shown in FIG. 7 and has a T-shaped body (142) with a main relief valve member (172) at one end of the body (142) mounted for movement in a generally horizontal direction and controlled by a diaphragm (176) at an opposite end of the body (142).

Abstract: A pressure relief valve including a valve member movable between open and closed positions to control fluid flow. A body member is provided which receives a piston operatively connected to the valve member for operating same. The piston defines a first chamber in the valve body extending above the piston and a second chamber extending below the piston. System fluid is introduced into the chambers and the differential fluid pressure in the chambers applies a loading force to the piston, and therefore to the valve member in its closed position. When the system pressure, and therefore the pressure in the chambers, exceeds a predetermined amount the pressure in one of the chambers is vented, causing the piston to move to an open position and permit opening movement of the valve member.

Abstract: A pressure control valve is provided comprising an inlet bore, an annular channel and a control spool. So as to obtain a low control deviation and good stability an annular channel is provided at the outlet side of the valve. The axial extension of said annular channel is smaller than the outlet flow area formed by said bores.

Abstract: A fluid pressure relief system and method for a pressure vessel or tank (10) having a normal vent (16) with a first pilot operated safety valve (18) and an emergency vent (62) having a second pilot operated safety valve (25). A vapor recovery line (20) is connected to relief valve (18) and collected at a vapor storage container (21). A manway (22) on the pressure vessel (10) shown in FIG. 2 defines the emergency vent (62) and a main valve member (66) has a counterweight (74) thereon to urge main valve member (66) to a seated closed position on nozzle (60). The first pilot operated safety valve (18) for the normal vent (16) is shown in FIG. 7 and has a T-shaped body (142) with a main relief valve member (172) at one end of the body (142) mounted for movement in a generally horizontal direction and controlled by a diaphragm (176) at an opposite end of the body (142).

Abstract: A pressure control system in which a pressure in a back pressure chamber of a flow control valve is controlled according to a throttle opening of a pilot valve to locate stationary the valve body of the flow control valve at a position corresponding to the throttle opening of the pilot valve. In the system, a fixed throttle is provided in an oil passage extended to the back pressure chamber of the flow control valve, thereby applying a dampering action to the valve body.

Abstract: A pressure control system in which a pressure in a back pressure chamber of a flow control valve is controlled according to a throttle opening of a pilot valve to locate stationary the valve body of the flow control valve at a position corresponding to the throttle opening of the pilot valve. In the system, a fixed throttle is provided in an oil passage extended to the back pressure chamber of the flow control valve, thereby applying a dampering action to the valve body.

Abstract: A fluid pressure relief system and method for a pressure vessel or tank (10) having a normal vent (16) with a first pilot operated safety valve (18) and an emergency vent (62) having a second pilot operated safety valve (25). A vapor recovery line (20) is connected to relief valve (18) and collected at a vapor storage container (21). A manway (22) on the pressure vessel (10) shown in FIG. 2 defines the emergency vent (62) and a main valve member (66) has a counterweight (74) thereon to urge main valve member (66) to a seated closed position on nozzle (60). The first pilot operated safety valve (18) for the normal vent (16) is shown in FIG. 7 and has a T-shaped body (142) with a main relief valve member (172) at one end of the body (142) mounted for movement in a generally horizontal direction and controlled by a diaphragm (176) at an opposite end of the body (142).

Abstract: A pressure relief valve including a valve member movable between open and closed positions to control fluid flow. A body member is provided which receives a piston operatively connected to the valve member for operating same. The piston defines a first chamber in the valve body extending above the piston and a second chamber extending below the piston. System fluid is introduced into the chambers and the differential fluid pressure in the chambers applies a loading force to the piston, and therefore to the valve member in its closed position. When the system pressure, and therefore the pressure in the chambers, exceeds a predetermined amount the pressure in one of the chambers is vented, causing the piston to move to an open position and permit opening movement of the valve member.

Abstract: A pneumatic pressure controller includes an actuator (50) and a throttling valve (12) for regulating a flow of gas (10). A pressure comparator (22) provides a modulated pressure signal (58) to the controller (50). The pressure comparator (22) includes an outlet orifice (70) for compensating at elevated supply pressures, P.sub.SUP.

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: An improved pilot valve is disclosed having a flow path from the inlet to the sense cavity via the valve spindle. An articulated disk is provided at the bottom of the valve spindle and is secured thereto by a hollow screw. Such articulated disk can adjust itself to the valve seat below to provide sealing of the valve to the seat in cases where the valve spindle is not perfectly axially aligned with the seat. A spacer between the upper and lower diaphragms is provided for maintenance of proper effective areas of such diaphragms and for prevention of resistance to valve stem motion.

Abstract: A precision pressure regulator not only providing makeup pressure in response to a low pressure condition, but also for providing the ability to vent off excess pressure. A system in a self-contained unit is used, thereby eliminating a need for an external power supply such as battery, electrical, or mechanical power. The precision pressure regulator also provides extremely accurate control of pressure even in the low pressure ranges of less than 1 inch of water column, and does so without the need for constant supervision by a skilled technician. A safe inert atmosphere is provided for chemical processes utilizing volatile and/or contaminant sensitive substances.