Abstract: The invention provides an airflow controller for a propulsion inlet system including a bleed section having two or more bleed plenum chambers, each of the chambers having a porous inlet surface and an exit surface and two or more plates slidably mounted to the bleed section and in fluid communication with the exit surface of the bleed section; and two or more plates being adjustable in multiple positions with respect to the exit surface of the bleed plenum chambers.

Abstract: A flow controller and a flow controlling method are adapted to be released from conventional restrictions by using a novel type called a pulse shot type. A pulse shot (opening/closing operation of a first cutoff valve (12) and, after that, opening/closing operation of a second cutoff valve (17)) is repeated. Simultaneously, a volume flow Q of process gas exhausted from the second cutoff valve (17) per unit time on the basis of after-filling pressure and after-exhaust pressure of the process gas in a gas filling capacity (13) measure by a pressure sensor (14). Furthermore, a mode of the pulse shot is changed to control the volume flow Q of the process gas exhausted from the second cutoff valve (17) per unit time.

Abstract: Hydraulic fill and drain of a clutch chamber is controlled with a blocking valve and a trim valve. The blocking valve selectively provides pressurized fluid to the trim valve which in turn selectively provides the pressurized fluid to the clutch chamber. Exhausting of the clutch chamber is effected through one of two alternate paths utilizing deactivation of one of the trim and blocking valves. Back up exhausting of the clutch chamber is effected through the other of the alternative paths. Such system allows for determination of valve failures and continued operation until such failures can be rectified.

Abstract: This invention concerns a gas assist mold dump valve positioned between a gas controller and a mold cavity. Preferably, the valve includes a pressure regulator having a body with a gas inlet and a gas outlet. A vent is formed in the body between the gas inlet and the gas outlet. The inlet is in fluid communication with the gas controller and the outlet is in fluid communication with the mold cavity. A piston is mounted for reciprocal motion within the body and is movable between a first position to close and a second position to open the vent. Finally, a check valve communicates with the inlet and the outlet and has an open position that allows gas to flow from the inlet to the outlet and a closed position to close off the flow of gas from the outlet to the inlet. In operation, gas entering the inlet urges the piston toward its first position, passes through the check valve into the outlet and then enters said mold cavity.

Abstract: Safety shutoff apparatus can close a valve using a pressure operable device coupled to and acting upon the valve. The proximal end of a pressure line is coupled to the pressure operable device for applying fluid pressure thereto in order to operate the pressure operable device. A soluble plug at the distal end of the pressure line can seal it in order to maintain pressure at the pressure operable device. By placing the soluble plug next to an object that is subject to leaking, the soluble plug can dissolve when a leak occurs and release the pressure in the pressure line. The released pressure results in closure of the valve when mechanical movement is produced by the pressure operable device in response to the release of pressure.

Abstract: A CMP slurry pumping system and method which uses the slurry pump inlet pressure as input to the pump controller, and the controller adjusts pump speed to account for variations in inlet pressure.

Abstract: A diaphragm operated regulator valve usable, e.g., for maintaining a preset gas pressure in a potable storage container, provides particularly effective at gas flow regulation as well as pressure regulation. The use of the word “fluid” as used herein can encompass both liquids and gasses. The valve includes a gas-balanced piston-tower diaphragm assembly that is freely supported, sealed, and operatively connected to a pressure-biasing adjustment. The diaphragm assembly permits axial movement relationships between valving channels or pathways, a valving-seal, and volume changes that take place in a low-pressure chamber. The valve 1) converts axial movement of the diaphragm into smooth transitional flow rates by varying the cross sectional areas of ingress and egress from an open valve position to a closed valve position and 2) has the ability to preset maximum flow rates.

Abstract: In a first aspect of the invention, a polishing device is provided. The polishing device includes a platen adapted to support a polishing pad and also includes a source of polishing slurry. Also included in the polishing device is a slurry supply line adapted to supply the polishing slurry from the source of polishing slurry to the polishing pad. The polishing device includes a pressure transducer installed along the slurry supply line and adapted to detect a pressure inside the slurry supply line. Numerous other aspects are provided.

Abstract: A control valve system includes a housing having an inlet port, a first output port, a second output port, and a valve chamber. A primary spool and a secondary spool are independently slidable in the valve chamber. The secondary spool has a first end for abutting against the primary spool and has a second end with a working surface area greater than the working surface areas at the ends of the primary spool. A solenoid valve assembly controllably connects the inlet port to the second end of the secondary spool. A biaser provides a biasing force to the primary spool. A first fluid passage through the primary spool provides fluid communication between the first output port and a second end of the primary spool for displacing the primary spool relative to the secondary spool in an energy saving mode, thereby regulating a pressure at the first output relative to the predetermined magnitude of the biasing force.

Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: An intelligent fluid flow regulation device that includes a pressure regulator within a fluid flow passage that has an associated throttling element moveable in the flow passage. A number of sensors in communication with the fluid flow passage and the throttling element are provided that communicate information from the sensors to a processor also contained within the regulation device. A communication unit is also included within the regulation device that affords communication between one or more devices that are external to the fluid flow regulation device and the processor within the regulation device.

Abstract: A method is for the continuous control of a position of a control valve. A control deviation from a position of the control valve, is determined as a controlled variable, in relation to a reference variable being determined. A manipulated variable is determined from the control deviation, by which manipulated variable the control valve is positioned and/or maintained in the position predefined by the reference variable. The improved method for the control of the position of a control valve, has the effect that failure of a valve position transmitter does not result in failure of the position control loop.

Abstract: An auto-relieving pressure modulating valve includes a spool, a solenoid that shifts the spool in an energized direction, and a spring arrangement. The spring arrangement functions to shift the spool from a relieving position to a neutral position, in the energized direction, without energizing the solenoid.

Abstract: A backflow prevention apparatus and method are provided for use in irrigation systems. An anti-siphoning device may have a housing, a plunger, a plunger retainer, and a cap. The housing has inlet and outlet channels formed therein, with the outlet channel running through the interior of the inlet channel. The plunger has a generally annular shape and is disposed to block water flow from the outlet channel into the inlet channel, but to allow flow from the inlet channel to the outlet channel. When the inlet channel is closed, the plunger permits air to flow into the outlet through the cap, the plunger retainer, and a central opening formed in the plunger. The plunger may have an elastomeric exterior to provide a more effective seal between the plunger and the inlet channel.

Abstract: A fluid pressure regulator is provided having a housing with an inlet and outlet for fluid, a valve located movably inside the housing and provided with a fluid transport member to allow passage of fluid from the inlet to the outlet. The regulator also has a pressure setting member and a space defined by one end of the valve and an end wall of the housing. The valve is moveable relative to the housing in response to a change in pressure within the space between a first position which at least partially aligns the fluid transport member with each of the inlet and the outlet and a second position in which there is no alignment of the fluid transport member with at least one of the inlet and the outlet. A passage is provided in open communication with the space and one of the inlet, the outlet, and the transport member. Methods of using the pressure regulator are also provided.

Abstract: A gas recirculation flow control method and apparatus for use in an evacuation system having a vacuum chamber into which a gas is introduced, a first vacuum pump for exhausting the gas from the vacuum chamber and reducing the pressure in the vacuum chamber to a desired pressure, a second vacuum pump for performing evacuation to lower the back pressure of the first vacuum pump below an allowable back pressure, and a gas recirculation line for returning a part of gas exhausted from the first vacuum pump to the vacuum chamber.

Abstract: The present invention pertains to methods and apparatus for controlling the pressure in a supercritical processing system. Active methods for controlling the pressure include anticipating a pressure deviation due to a solute addition to a system, and changing the pressure within the system to compensate for the deviation. In this way, a desired pressure is achieved when the solute is added, without phase separation of the solute from the solvent. Pressure is adjusted by changing the volume of the supercritical processing system. Passive methods include adjusting the pressure of a supercritical system by changing the volume in response to a pressure deviation from a desired pressure. Apparatus for controlling the pressure in a supercritical processing system are described.

Abstract: A programmable circuit detects drop in pressure of a supplied pressurized gas below a predetermined threshold pressure and automatically switches to a different supply of pressurized gas and automatically contacts a remotely located host computer. The circuit sends status data to the host computer and enters a server mode in which the circuit performs commands issued by the host computer. The commands include commands to change data of the programmable circuit and to download new programming. The predetermined threshold pressure is established by manually setting the supplied pressurized gas to a desired pressure and causing the programmable circuit to measure the pressure of supplied gas and to store the measured pressure as the threshold pressure.

Abstract: A compact, portable and NIST traceable pressure source dynamically generates very low pressures includes at least one adjustable valves in-line with a fluid, such as air, flowing through the valve. A differential pressure is created across a pressure control device downstream from the valve. The differential pressure varies depending on the volume of the gas flow and the amount of resistance to the gas flow. The pressure generating device utilizes a miniature pump to create a pressure, or, alternatively, a vacuum, that causes gas flow. The pressure generating device is compact and capable of providing a very low and stable differential pressure by using a dynamic flow that compensates for temperature changes and volume changes. The compact module may be configured as a plug-in module for existing handheld calibrators for operator ease of use.

Abstract: The invention describes a method and a device for introducing volatile liquids into housings of electrical components, in particular of passive electrical components or of electrochemical cells, and for closing the housings. The method can be carried out using an evacuable chamber (1), a conveyor device (2) for conveying the components (4), a gas pressure device (9, 12, 13, 14) for generating a gas pressure atmosphere in the chamber, a filling device (5, 8, 11, 15) for introducing a volatile liquid into a component (4), a closing device (6, 17) for closing the component (4), and using a programmable sequence control means (10), which controls the conveyor device (2), the gas pressure device (9, 12, 13, 14), the filling device (5, 8, 11, 15) and/or the closing device (6) in such a way that these devices interact in a predetermined manner.

Abstract: A method of damping surges in a liquid system includes providing in the system, a surge vessel in which there is trapped air or other gas, the surge vessel being positioned so that in the event of a surge in the system (10), the volume of trapped air or other gas within the surge vessel changes to damp the surge, the method including maintaining generally constant the mass of the trapped air or other gas in the surge vessel is maintained generally constant, irrespective of the liquid level within the surge vessel.

Abstract: In a method and apparatus for cleaning pipe-shaped filter elements arranged in a housing including a separation wall dividing the housing into a clean gas space and a raw gas space into which the filter elements extend from the clean gas space through the separation wall and the raw gas is directed from the raw gas space through the filter elements into the clean gas space while dust is removed from the raw gas and collected on the filter elements, the filter elements are cleaned from time to time by supplying momentarily pressurized flushing gas to the clean air space which, at the same time, is closed to generate a flushing gas pulse providing for a backflow of clean gas from the clean gas space to the raw gas space, which dislodges dust collected on the filter elements.

Abstract: A method is provided for controlling hydraulic flow through a valve in fluid communication with a pump and a hydraulic actuator. The method includes monitoring load pressure of the valve, and selecting a flow limit and a pressure limit of the valve. A flow-pressure relationship in the valve is determined based on the flow limit, the pressure limit, and a desired flow-pressure characteristic. A hydraulic flow rate command is computed based on the determined flow pressure relationship and the monitored load pressure of the valve.

Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: The invention concerns a method supplying volume streams of fluids in channels or capillaries of small stream cross sections, more particularly chromatographic separating columns for the analytical fluid metrology, wherein a delivery device for delivering a volume stream of the fluid through an operating channel and a pressure measuring device for measuring the pressure in the operating channel is provided, wherein a measurement of the volume stream is possible, characterized by the following steps: a) Recording a time reference pressure course using the pressure measuring device in the operating channel, while the delivery device delivers an essentially constant, pre-determinable reference volume stream through the operating channel of a fluid with properties, more particularly flow properties, varying over time; b) Calculation of a time development of the operating pressure, which corresponds to the essentially constant and preferably small operating volume stream through the operating channel, which is d

Abstract: A pneumatic actuation control system includes a pressure controller, an eductor and a valve. The pressure controller is capable of directing an amount of fluid to the contained volume such that a pressure within the contained volume exceeds a pressure external to the contained volume by a predefined positive pressure. The pressure controller can also adjust the pressure within the contained volume when the pressure external to the contained volume changes. The eductor can draw fluid from the contained volume to thereby decrease the pressure within the contained volume. The valve is controllably operable in either a pressure mode or a vacuum mode, where the valve either permits the pressure controller to provide fluid to the contained volume, or permits the eductor to draw fluid from the contained volume. As such, the system provides precision pressure control over a broad range of external pressures while compensating for rapid pressure changes.

Abstract: Manual stent manipulation before implantation results in foreign body contamination and increased neointimal hyperplasia. Rinsing commercially available sterile stents with high pressure immediately before implantation eliminates residual surface stent contaminants and reduces inflammation elicited by stent struts. Ex-vivo stent expansion and surface analysis revealed that rinsed stents had fewer surface contaminants than untouched or handled stents. In a porcine stent restenosis model, rinsed stents elicited less inflammation and less neointimal hyperplasia at one month than handled and untouched stents. Pressure-rinsing of coronary stents immediately before implantation reduces inflammation and neointimal hyperplasia.

Abstract: The present invention relates to a process of utility conservation control methodology within a fluid pumping distribution system. With fluid flowing through a distribution grid, the pressure at any given point becomes a function of system flow. At a specific flow rate, the pressure at this point is a function of flow rate. This invention is a process that continuously adjusts the pressure requirement for the pumping system by varying the pump speed according to the system head curve details. This invention produces several benefits for a fluid distribution system including reducing utility costs and equipment aging.

Abstract: An improved fluid control valve includes a valve body with an inlet and an outlet. A sealing member is connected to the valve body conformed to seal the inlet and form a pressure chamber. A push rod is connected to the sealing member and a sleeve is provided which encompasses the push rod. A piston, forming an equalization chamber, is connected to the sleeve and to the push rod so that when the piston moves in one direction the sealing member is moved in the opposite direction until camover when both move in the same direction.

Abstract: The invention relates to a controllable valve, particularly for delivering a pulsed flow of fluid. It comprises a valve body (10); a valve seat (12) dividing the inside of the body into an inlet chamber (14) and an outlet chamber (16); a valve shutter element (22) capable of moving; an actuator (24) comprising a stationary control part (26) for receiving control signals and a moving part (28); first rigid means of connection (30) for connecting the said moving part of the actuator (28) to the said shutter element (22); a mechanical stop (40′); a member (38) that can be compressed under the effect of a force applied to it, comprising a first end secured to the said mechanical stop; and second rigid means (36′) for dynamically connecting one of the faces of the said shutter element (22b) to the second end of the said compressible member (38).

Abstract: A mass flow controller includes a thermal mass flow sensor in combination with a pressure sensor to provide a mass flow controller that is relatively insensitive to fluctuations in input pressure. The pressure sensor and thermal sensor respectively provide signals to an electronic controller indicating the measured inlet flow rate and the pressure within the dead volume. The electronic controller employs the measured pressure to compensate the measured inlet flow rate and to thereby produce a compensated measure of the outlet flow rate, which may be used to operate a mass flow controller control valve.

Abstract: A main water supply (1) is equipped with a main valve (2) followed by a first main pipe (3) running through a first check valve (4), and further to a first adapter (6) while a pilot pipe (7) runs from the main valve (2) through a secondary valve (9) and further a pilot coupling (16). A pressure pipe (12) runs to a secondary valve (9). From the first main pipe (3), a branch pipe (26) runs through a second check valve (28) to a water heater (27) and a second main pipe (29) runs to a second adapter (6.1) through a third check valve (30). A solenoid valve (17) is operated by a timer (18) or by the control signal of a household appliance. Pressure sensors (23, 33) signal of a household appliance. Pressure sensors (23, 33) signal to lamps (23, 34) on a panel(25).

Abstract: The present invention provides a fuel system for an internal combustion engine powered by fuel that includes a fuel tank having a wall defining a volume. The fuel system also includes a pump that is disposed proximate the fuel tank and operatively connected to the volume. The fuel system further includes piping that is coupled to the pump and is operatively connected to the internal combustion engine. A pressure regulator with a self-contained valve assembly is disposed in at least one of the pump or the piping.

Abstract: A variable device for regulating the outlet pressure of a fluid from a valve body, includes a pressure-sensing chamber having a wall formed by a resilient self-restoring diaphragm which is responsive to pressure in the chamber. A valve element connected to the diaphragm controls flow into the chamber. Increased pressure in the chamber decreases the flow into the chamber and decreasing pressure increases flow whereby fluid flow out from the chamber is maintained at a desired pressure. The outlet pressure is adjusted by deflecting the diaphragm in a direction to open the valve while permitting a section of the diaphragm connected to the valve member to remain responsive to the pressure in the chamber. An adjustment cover is provided to adjustably deflect the diaphragm and includes a catch mechanism to allow adjustment of the fluid outlet pressures and also retain the device at a desired value. An indicator arrangement may be provided to visually indicate the fluid outlet pressure.

Abstract: A CMP slurry pumping system and method which uses the slurry pump inlet pressure as input to the pump controller, and the controller adjusts pump speed to account for variations in inlet pressure.

Abstract: During the pumping of corrosive gases, it is advantageous to admit a seal gas to endangered pumping chambers at a lower flow rate and a higher pressure than the corrosive gases. Inert gas from a supply (3) has its pressure reduced by a pressure reducer (6). An on/off valve (7) controls a flow of the inert gas through a flow restriction (8) which restricts the flow of inert gas to appropriate sealing gas rates at an outlet (4). After pumping the corrosive gas, a control valve (12) in a bypass line (11) causes the inert gas to be supplied to the outlet (4) at a higher flow rate for purging the pump.

Abstract: The object of this invention is to provide a method and system for automatically controlling water level in a storage tank through a wireless control process. This system includes an intake chamber (24), an intake pumping means (22) set within the chamber (24), a water feed pipe (36) extending from the pumping means (22) to a water storage tank (300), a pressure sensing means (34) for sensing water pressure within the pipe (36), a check valve (33) for preventing backflow of water within the pipe (36), and a drive controller (110) for processing data from the pressure sensing means (34) and outputting a signal to a main controller (100). This method and system senses water pressure within the water feed pipe using the water pressure sensing means to automatically and effectively control the water level within the water storage tank through a wireless control process, particularly in the case of an excessively long water feed pipe.

Abstract: A system for maintaining a surcharge on a sanitary sewer collection system to minimize the pressure differential across pipe walls carrying the waste and to offset the buoyant effects of hydrostatic pressure on the outside of the pipe. Pinch valves or other remotely controllable pipe closing devices are employed in combination with a system of monitors and a centralized control system to maintain and periodically release fluid from the surcharged system.

Abstract: A differential pressure based flow rate measurement device is provided which is coupled to surfaces of a blade 30 within a damper assembly 10, such as that provided within a variable air volume (VAV) box or within a liquid valve assembly. A blade 30 which includes a leading surface 32 opposite a trailing surface 34 is fitted with a sensing structure 50. The sensing structure 50 includes portions 52, 54 which extend away from the leading surface 32. Sensing holes 56 pass into a hollow interior of the sensing structure 50 and pass on to a pressure sensor 60. A similar sensing structure 50 is also provided extending from the trailing surface 34 which also has sensing holes 56 located therein. The sensing holes 56 coupled to the trailing surface 34 also lead to the pressure sensor 60 so that a differential pressure between the sensing holes 56 on either sides of the blade 30 can be measured.

Abstract: A rotary blowout preventer has a first and a second fluid circuit. Each of the fluid circuits are defined into and out of a stationary body and between the stationary body, a rotating body, and two seals. The first fluid circuit is physically independent from the second fluid circuit although they share a seal interface. A fluid is introduced into the first fluid circuit at a pressure responsive to the well bore pressure. A fluid is introduced into the second fluid circuit at a pressure responsive to and lower than the pressure of the fluid in the first circuit. Adjustable orifices are connected to the outlet of the first and second fluid circuits to control such pressures within the circuits. Such pressures affect the wear rates of the seals. The system can therefore control the wear rate of one seal relative to another seal. A thrust bearing is added to share the load placed upon the upper bearings. The thrust bearing is connected between the top end of a packer sleeve and the stationary body.

Abstract: A programmable circuit detects drop in pressure of a supplied pressurized gas below a predetermined threshold pressure and automatically switches to a different supply of pressurized gas and automatically contacts a remotely located host computer. The circuit sends status data to the host computer and enters a server mode in which the circuit performs commands issued by the host computer. The commands include commands to change data of the programmable circuit and to download new programming. The predetermined threshold pressure is established by manually setting the supplied pressurized gas to a desired pressure and causing the programmable circuit to measure the pressure of supplied gas and to store the measured pressure as the threshold pressure.

Abstract: A control system for digitally monitoring and/or controlling pressure to a pneumatic load such as a stop/suckback valve. Pressure is sensed in the pneumatic fluid input lines to the pneumatic load, and a closed loop control is used to maintain the pressure at a predetermined level. In an alternative embodiment, the control system is used to ensure equal dispensing in multi-point dispense apparatus. Thus, pressure is sensed downstream of each valve in fluid communication with a respective nozzle. Any pressure differential detected is corrected by appropriate valve adjustment.

Abstract: A method and a valve apparatus for counteracting harmful pressure pulses caused by rapid retardation of a liquid in a hydraulic system comprising a pump for the supply of liquid to a conduit stretch containing a non-liquid-filled volume. The valve apparatus comprises a main valve having an inlet connected to a reservoir for pressurised gas, a first valve chamber connected in use to said volume, and a regulating unit for controlling the supply of pressurised gas to the first chamber.

Abstract: A method of controlling occurrence of severe slugging in a riser (6) of a pipeline arrangement (2) comprising a riser base (8) and pipeline (4) conveying a multiphase fluid system in which the gas phase may be natural gas. The upper end of riser (6) is connected to a separator vessel (10) wherein the gas phase of the multiphase fluid system is separated from the liquid phase so that the separated gas leaves through gas outlet pipe (12) controlled by a valve (14), and the liquid leaves through an outlet pipe (16) controlled by valve (18). The valve (14) regulates the velocity of gas along the pipeline towards the riser.

Abstract: Arrangement and method for the prevention of water entering a pneumatic controller of a vacuum sewer system through a breather line. The proposed pneumatic controller is a non-bleeding controller preventing continuous flow of air from the breather line through the controller. The volume of breather air entering the controller during an evacuation cycle is smaller than the volume of a water trap provided in the breather line. The water trap removes water from the breather air before it enters the controller.

Abstract: A pump assembly flows pressurized engine oil to HEUI fuel injectors in a diesel engine. The assembly includes an inlet throttle valve which controls the volume of oil flowed to the pump dependent upon the difference between the pump outlet pressure and a desired outlet pressure determined by an electronic control module for the diesel engine.

Abstract: Atomized particles within a desired size range (e.g., 1 micron to about 5 microns) are produced from two immiscible fluids, a first fluid source containing the formulation to be atomized, and a second fluid source which is contained in a pressure chamber surrounding at least the area where the first liquid is to be provided. The invention provides methods for: the production of templates for microfabrication, such as particles that serve as templates for self-assembly of monolayers; the creation of small particles to serve as building blocks for the microassembly of objects; and the use of an atomizate to etch configurations and/or patterns onto the surface of an object by removing a selected portion of the surface.

Abstract: The present invention is a pressure feedback circuit for use with a vacuum pressure control circuit. The pressure feedback circuit detects the occurrence of, and controls the generation of vacuum pressure under, External Override Conditions (“EOCs”). During EOCs, which typically include emergency stop conditions or loss of electrical power to the vacuum pressure circuit, the pressure feedback circuit senses the condition of the output vacuum pressure port and supplies feedback to the vacuum pressure control circuit thereby maintaining the last output state of the vacuum pressure control circuit.

Abstract: A method and system for controlling the rate of fluid flow. A flow restrictor having known pressure drop and flow rate characteristics provided in a passage through which the fluid, preferably a gas, flows. An upstream pressure sensor determines the pressure of fluid in the flow passage upstream of the flow restrictor. A downstream pressure sensor determines the pressure of fluid in the flow passage downstream of said flow restrictor. A pressure regulator adjusts the pressure of fluid upstream or downstream of the flow restrictor based on the pressure drop across the flow restrictor so that the actual pressure drop across the flow restrictor closely corresponds to the pressure drop associated with a desired rate of fluid flow.

Abstract: A multi-function pressure relief valve having a moveable seat and a needle is mounted on a fuel vapor separator. The needle is connected to a float assembly for opening and closing the pressure relief valve for venting an internal chamber of the fuel vapor separator. The moveable seat is biased to engage the needle for relieving excess pressure when vapor pressure in the internal chamber exceeds a biasing force on the movable seat. The valve opens in response to at least one of (1) changing fluid level in the fuel vapor separator, and (2) excess vapor pressure within the vapor fuel separator. During operation, the valve vents an internal chamber of the fuel vapor separator by disengaging the needle from the movable seat using a float attached to the needle. The valve closes when the float reaches a desired position to pressurize the internal chamber by engaging the needle to the movable seat.