Abstract: A flow control device has a valve body having an inlet, an outlet, and a flow path connecting the inlet and the outlet and a unitary trim cartridge assembly secured to the valve body. The trim cartridge assembly has a cage disposed in the flow path, a bonnet coupled to the cage, and a retaining element disposed between the cage and the bonnet. The cage includes an exterior groove formed on an exterior surface of the cage, the bonnet includes an interior groove formed on an interior surface of the bonnet, and the retaining element extends into the interior groove and the exterior groove. A height of the interior groove and/or a height of the exterior groove is greater than a height of the retaining element to allow the cage to move longitudinally within the bonnet with the bonnet and cage assembled.

Abstract: A solenoid-operated valve assembly that reduces the jet flow of fluid or gas in an axially exiting valve. The valve assembly comprises a spool valve, a valve member housing, and a flow path. The spool valve comprises a fluid communication channel, a tail, and an inlet seat. The valve member housing comprises at least one inlet, at least one nozzle flow director, and at least one outlet. The flow path begins at the at least one inlet and exits at the at least one outlet. The at least one nozzle flow director is within the flow path. The spool valve moves axially within the valve member housing between a closed position and an open position. The inlet seat closes the at least one flow path at the inlet when the spool valve is in the closed position. A method of operation of the solenoid-operated valve assembly is also provided.

Abstract: A gas feed method for a gas engine or dual-fuel engine in which combustion gas (G) is burned with combustion air (L). A gas valve (1) for the feed of combustion gas (G) into the combustion air (L) is arranged upstream of the gas engine or dual-fuel engine. The combustion gas (G) is fed in uncontrolled fashion to the gas valve (1) independently of the operating state of the gas engine or dual-fuel engine. The invention furthermore relates to a gas supply apparatus. A gas valve (1) for the feed of combustion gas (G) into the combustion air (L) is arranged in the gas feed (10) upstream of the gas engine or dual-fuel engine. Control of the gas pressure in a manner dependent on the operating state of the gas engine or dual-fuel engine is not provided upstream of the gas valve (1).

Abstract: An example control valve is disclosed herein and includes a valve body having a substantially axial fluid flow path extending from an upstream face surface to a downstream face surface of the valve body. A crank is disposed within the valve body, and a reciprocating valve trim, external to the valve body, is coupled to the crank and abuts the downstream face surface of the valve body.

Abstract: An embodiment herein provides a control valve having a hollow piston 104. The hollow piston 104 includes a hollow portion 106. The hollow portion 106 includes at least one opening 108 along the side wall of the hollow piston 104. The fluid from an inlet port 116 flows to an outlet port 118 through the at least one opening 108 within the hollow portion 106 along the side wall of the hollow piston 104, when the hollow piston 104 move upwards and the at least one opening 108 within the hollow portion 106 along the side wall of the hollow piston 104 is positioned above the topmost sealing ring 113. The effective flow rate through the control valve may be controlled depending on (a) the relative positioning of the opening 108 within the hollow portion 106 along the side wall of the hollow piston 104 with respect to the topmost sealing ring 113 and (b) the geometry and size of each of the at least one of opening 108 along the side wall of the hollow piston 104.

Abstract: A pneumatic valve is disclosed comprising: an outer housing formed from a continuous single-piece of material and defining a fluid inlet port and a fluid outlet port; a separate piston sleeve housed within the housing; and a piston slidably mounted within the piston sleeve.

Abstract: An erosion protection system for closing sleeve assemblies is disclosed. A closing sleeve assembly including a housing; a port formed in the housing; a sealing surface formed in the housing adjacent to the port; a closing sleeve configured to move between an open position, in which a fluid flow through the port is permitted, and a closed position, in which the fluid flow through the port is prevented, the closing sleeve including a seal configured to engage with the sealing surface to form a fluid and pressure tight seal when the closing sleeve is in the closed position; and a protective sleeve configured to extend toward the port to substantially cover the sealing surface when the closing sleeve is moved to the open position and retract away from the port when the closing sleeve is moved to the closed position.

Abstract: A circulating sub having an elongate outer member and an elongate inner member positioned within the outer member. Locking members releasably maintain the inner and outer members in a longitudinally fixed relationship. The sub may be activated by a single ball. The ball engages with the locking members and unlocks the inner member from the outer member. The increase of fluid pressure within the sub causes the inner member to move downward within the outer member. Downward movement of the inner member opens exit ports on the outer member to allow fluid to flow into a wellbore surrounding the sub. The decrease of fluid pressure within the sub causes the inner member to move upward within the outer member. Upward movement of the inner member seals the exit ports and deactivates the sub. Once the sub is deactivated, the ball may be expelled from the sub.

Abstract: A dust collector includes a pneumatic duct chamber and a bag house interconnected by a valve assembly to provide incremental and varying air pressure within the bag house to prevent damage to the filter bags disposed within the bag house due to sudden changes in air pressure.

Abstract: A tubular actuation system includes a housing and an activatable sleeve including a first assembly having a first radially movable seat, a second assembly having a second radially movable seat, and an insert disposed between the first and second assemblies. The activatable sleeve is movable longitudinally from a first position to a second position, and from a second position to a third position within the housing.

Abstract: A steam valve includes: a valve main body which has, on the inside thereof, a flow path through which steam flows, and has a valve seat formed in a portion of the flow path; a valve body which comes into contact with the valve seat, thereby shutting off the flow path, and is separated from the valve seat, thereby opening the flow path; a valve shaft which is connected to the valve body, extends in an upward direction from the valve body, and moves up and down, thereby bringing the valve body into contact with the valve seat and separating the valve body from the valve seat; a hydraulic drive unit which is disposed to be separated in a horizontal direction from the valve main body, at a position which does not overlap the valve main body in a case of being viewed from above, and has a drive rod which is driven forward and backward by oil pressure; a first link unit which connects the drive rod and the valve shaft and transmits the forward and backward drive of the drive rod to the valve shaft, thereby moving t

Abstract: An electromagnetic solenoid is disclosed. The solenoid includes a coil, a bobbin, a flux sleeve, an armature, and a pole piece, arranged in such a way that the solenoid is robust against misalignment of the pole piece with the flux sleeve. The configuration facilitates the integration of either the pole piece or the flux sleeve into a hydraulic circuit.

Abstract: A specially designed rotary indexing system and associated operational methods are incorporated in a downhole control device, representatively a sliding sleeve valve, having an outer tubular member in which an annular plug seat is coaxially disposed. The plug seat is resiliently expandable between a first diameter and a larger second diameter and is illustratively of a circumferentially segmented construction. The rotary indexing system is operative to detect the number of plug members that pass through and diametrically expand the plug seat, and responsively preclude passage of further plug members therethrough when such number reaches a predetermined magnitude. Such predetermined magnitude is correlated to the total rotation of an indexing system counter ring portion rotationally driven by axial camming forces transmitted to the rotary indexing system by successive plug member passage-generated diametrical expansions of the plug seat.

Abstract: Low pressure oxygen or other breathable gas is supplied from a tank or other source to a patient or other person through a flexible plastic tube, and a safety valve system is connected between the source and the tube. The valve system includes a valve member having a tubular outlet portion and supported for axial movement within a valve body having an inlet connected to the gas source. Fluid passages are formed within the valve member and valve body, and the valve member shifts axially to an open position in response to connecting the flexible tube to the tubular outlet portion of the valve member. The valve member shifts to a closed position in response to removing the tube from the tubular outlet portion, and the supply gas holds the valve member in the closed position.

Abstract: A steplessly adjustable hydraulic insert valve has a housing defining a radial direction and an end side in an installation direction. An inflow connector on the end side is connectable to a pressure medium source. First and second working connectors and a return connector are arranged in the radial direction. The return connector is connectable to a pressure medium tank. The housing has an axial bore and an actuator guided movably therein. The actuator can be held in an axial center position by at least one spring and is adjustable steplessly axially out of the center position by controllable actuation. At least one of the working connectors is fluidically connectable to the return connector by axial adjustment of the actuator. The actuator has a radial widened portion with first and second control edges for steplessly opening and/or closing first and second radial openings, respectively, of the return connector.

Abstract: A containment housing includes a hexagonal portion configured to receive a linear variable differential transformer. The containment housing also includes a housing contact flange adjacent to the hexagonal portion. The housing contact flange has a flange face. The containment housing further includes an external threaded portion formed between the flange face and a containment housing end. The external threaded portion is configured to engage a fuel control housing portion of a fuel control. A length is defined between the flange face and the containment housing end, and a ratio of the length to a width of the housing contact flange is between 8.22 and 8.94.

Abstract: A flow control device is disclosed. The flow control device includes a solenoid, the solenoid including an armature. Also, a piston connected to the armature. The piston includes a primary orifice. The piston having an open position and a closed position. A piston spring connected to the piston is also includes and at least one secondary orifice. The movement of the piston to the open position at least partially opens the at least one secondary orifice and the movement of the piston to the closed position at least partially closes the at least one secondary orifice. The movement of the armature actuates the piston movement and controls fluid flow from the primary orifice through the at least one secondary orifice.

Abstract: Seal assemblies for use with fluid valves are described. An example valve trim assembly for use with fluid valves includes a cage and a seal assembly to be positioned in at least one of the cage, a cage retainer or a plug. The seal assembly includes a first seal and a first scraper. The first seal is to provide a load to the first scraper to prevent the ingress of contaminate to a dynamic sealing surface to be engaged by the first seal. Additionally, the seal assembly includes a second seal and a second scraper. The second seal is to provide a load to the second scraper. Further, the seal assembly includes a spacer between the first and second seals.

Abstract: A Joule-Thompson or other throttling valve comprises an outlet channel (7) in which swirl imparting means (10) impose a swirling motion to the cooled fluid stream discharged by the valve, thereby inducing liquid droplets to swirl towards the outer periphery (7A) of the fluid outlet channel (7) and to coalesce into enlarged liquid droplets (17) which can be separated easily from a gaseous or other carrier fluid.

Abstract: A valve assembly includes a housing with a supply port receiving working fluid from a working fluid source, a control port connected to a working device, and a vent port for returning working fluid to the working fluid source. A spool with a spool bore in fluid communication with the control port controls the flow of working fluid between the supply port and the control port and between the control port and the vent port. An actuator assembly selectively alters the position of the spool. In a high pressure mode, the supply port is in fluid communication with the spool bore at a first pressure. In a pressure relief mode, the vent port is in fluid communication with the spool bore. In a pressure regulating mode, the supply port is in fluid communication with the spool bore at a second pressure which is less than the first pressure.

Abstract: A valve is provided including a first valve member and a second valve member. The first valve member includes a first step and a first orifice adjacent the first step. The second valve member includes a second step and a second orifice adjacent the second step. The second valve member is movable relative to the first valve member between an open position, in which the first orifice is fluidly connected the second orifice, and a closed position, in which the first orifice is substantially fluidly disconnected from the second orifice. The first and second steps are fluidly connected to the second orifice and substantially fluidly disconnected from the first orifice when the second valve member is in the closed position, and the first and second steps are fluidly connected to the first and second orifices when the second valve member is in the open position.

Abstract: A metering valve assembly includes a metering valve sleeve and a metering valve spool. The metering valve sleeve includes an inlet window set and an outlet window set with a first outlet window having a first logarithmic contour and a second outlet window having a second logarithmic contour. A ratio of an inner width of the first outlet window to an inner length of the first outlet window is between 1.48 and 1.52. A ratio of an inner width of the second outlet window to an inner length of the second outlet window is between 2.21 and 2.29. The metering valve spool includes first, second, and third cylindrical portions. The metering valve spool is configured to move bi-directionally along a longitudinal axis of the metering valve sleeve and control fluid flow between the inlet window set and the outlet window set relative to the first, second, and third cylindrical portions.

Abstract: A servo minimum pressure valve assembly includes a servo minimum pressure sleeve and a servo minimum pressure valve spool. The servo minimum pressure sleeve includes an inlet aperture, a first window set, a second window set, and a third window set. A ratio of an outlet window diameter of the first window set to an outlet window diameter of the second window set is between 2.34 and 2.65. The outlet window diameter of the second window set is greater than an outlet window diameter of the third window set. The servo minimum pressure valve spool is configured to move bi-directionally along a longitudinal axis of the servo minimum pressure valve sleeve. The servo minimum pressure valve spool includes a cylindrical portion to control a fluid flow between the inlet aperture of the servo minimum pressure sleeve and the first, second, and third window sets of the servo minimum pressure sleeve.

Abstract: The invention relates to an actuator (10) for controlling a fluid flow which comprises a valve housing (11), a flow restrictor (18) and a valve seat (16), in which the flow restrictor (18) is designed such that the flow restrictor (18)—together with a closure (22) which is connected to the valve housing (12)—will form a pressure-relieving chamber (28), and as a result, a relative movement of the flow restrictor (18) and the chamber closure (22) together with the actuation will cause the volume of the pressure-relieving chamber (28) to change as a function of the direction of movement, and the flow restrictor (18) has a recess (24) which will allow the fluid to be controlled to flow into the pressure-relieving chamber (28).

Abstract: A valve is provided including a first valve member and a second valve member. The first valve member includes a first step and a first orifice adjacent the first step. The second valve member includes a second step and a second orifice adjacent the second step. The second valve member is movable relative to the first valve member between an open position, in which the first orifice is fluidly connected the second orifice, and a closed position, in which the first orifice is substantially fluidly disconnected from the second orifice. The first and second steps are fluidly connected to the second orifice and substantially fluidly disconnected from the first orifice when the second valve member is in the closed position, and the first and second steps are fluidly connected to the first and second orifices when the second valve member is in the open position.

Abstract: In accordance with the present invention, there is provided an axial drag control valve which includes an internal disk stack trim and an internal actuator. The fluid inlet and outlet of the valve are disclosed along a common axis, which is further shared with the actuator of the valve. The actuator moves along this particular axis to control the fluid flow rate, pressure, or temperature of the system. The valve actuator may be powered by air from an external source.

Abstract: In accordance with the present invention, there is provided an axial drag control valve which includes an internal disk stack trim and an internal actuator. The fluid inlet and outlet of the valve are disclosed along a common axis, which is further shared with both the plug and the actuator. The plug and actuator move along this particular axis to control the fluid flow rate, pressure, or temperature of the system. The valve actuator may be powered by an operating fluid such as air supplied from an external source. A special, two-part packing with a lantern ring and leak-off port provides protection and safety for the actuator.

Abstract: A fluid control device including a valve body, a control member, and a one-piece bonnet. The valve body defines a flow path for a fluid. The control member is disposed in the valve body and adapted for displacement between at least a first position and a second position. The one-piece bonnet is coupled to the valve body and defines a protrusion. The protrusion extends at least partially into the flow path and is arranged to direct at least some of the fluid flowing along the flow path when the control member is disposed between the first position and the second position.

Abstract: A valve assembly is disclosed. The valve assembly may include a housing having an interior chamber, inlet port, outlet port, and control port. The valve assembly may further include a valve member configured to move within the interior chamber to permit flow between the inlet port and the control port and between the outlet port and the control port. The valve assembly may further include and an actuator configured to move the valve member to form a first opening and second opening to create flow forces tending to close the first and second opening. The valve member may also include a passageway in the valve member configured to direct fluid flow from the inlet port to the control port and from the control port to the outlet port, and counteract the flow forces at the first and second opening.

Abstract: A valve is provided including a first valve member and a second valve member. The first valve member includes a first step and a first orifice adjacent the first step. The second valve member includes a second step and a second orifice adjacent the second step. The second valve member is movable relative to the first valve member between an open position, in which the first orifice is fluidly connected the second orifice, and a closed position, in which the first orifice is substantially fluidly disconnected from the second orifice. The first and second steps are fluidly connected to the second orifice and substantially fluidly disconnected from the first orifice when the second valve member is in the closed position, and the first and second steps are fluidly connected to the first and second orifices when the second valve member is in the open position.

Abstract: A valve includes a body, a cage, a plug, a stem, a stop ring, and a pilot plug. The cage includes at least one cage port there through allowing fluid communication between the fluid inlet and the fluid outlet. The plug is movable linearly within the cage to allow fluid communication between the fluid inlet and the fluid outlet when the valve is open. The pilot plug is adapted to transfer downward force from the stem to the plug by contacting the stop ring of the plug and thereby urging the plug downward through the cage when the stem moves linearly downward to adjust the valve from the closed position to the open position. In an alternative embodiment, the stem includes a collar adapted to contact the plug and adjust the valve from the closed position to an open position.

Abstract: A directional or flow control valve has an inlet connection, an outlet connection, and a slide that controls a fluid connection between the inlet connection and the outlet connection and is configured to control the fluid connection in at least two adjustable opening cross-sections that are spaced axially apart from each other and allow a partial flow to pass through.

Abstract: A variable pressure reducing device includes a hollow housing body formed with an inlet opening, an outlet opening spaced apart from the inlet opening, and an inner wall surface. The variable pressure reducing device further includes an intake tube that extends into the housing body from the inlet opening. The intake tube is formed with an inlet channel and is further formed with an outer tube surface that cooperates with the inner wall surface to form an outlet channel in fluid communication with the outlet opening. The variable pressure reducing device also includes a redirection structure movably mounted in the housing body and movable relative to the intake tube between a redirecting state and a sealing state.

Abstract: A valve seat apparatus for use with fluid valves is described. An example valve seat apparatus includes a flexible seal disposed between a cage and a valve body such that an outer seating surface of a closure member slidably coupled to the cage slidingly engages the flexible seal to prevent fluid flow through the valve body when the valve is in a closed position and an end of the closure member is not driven into abutting engagement with another seating surface when the valve is in the closed position.

Abstract: A valve (200) for routing a fluid includes a housing (220) having an inlet (222) and at least one outlet port (224). A valve member (218) is located in the housing (220). The valve (218) member has a wall (232) enclosing a cavity (230). A plurality of inlet openings (234) is formed in the wall (232). At least one of the plurality of inlet openings (234) fluidly connects the inlet (222) of the housing (220) with the cavity (230), and the at least one outlet port (224) may be selectively fluidly connected to the cavity (230).

Abstract: A valve assembly (10) comprising a valve member (14) having surfaces (70, 72, 74, 76, 78) radially sized and axially situated to provide an axial sealing force to insure leakfree operation. When the valve member (14) is in a supply position, the sum of fluid forces imposed on the radial surfaces is positive towards supply position, and, when the valve member (14) is a nonsupply position, the sum of fluid forces imposed on the radial surfaces is positive towards the nonsupply position. The valve assembly (10) is compatible with a piezo-type actuator (18) that provides lift-shift forces early in its stroke. Once movement of the valve member (14) has been initiated by the actuator (18), the fluid forces can be relied upon to complete the shift and seal the valve member (14) against the corresponding seat (40/42).

Abstract: A fluid control device including a valve body, a control member, and a one-piece bonnet. The valve body defines a flow path for a fluid. The control member is disposed in the valve body and adapted for displacement between at least a first position and a second position. The one-piece bonnet is coupled to the valve body and defines a protrusion. The protrusion extends at least partially into the flow path and is arranged to direct at least some of the fluid flowing along the flow path when the control member is disposed between the first position and the second position.

Abstract: An essentially fully balanced plug valve is presented in which the flow control contour is interior to the moving member. The sealing edge of the moving member is at the exterior surface relative to the interior contour. This sealing edge is formed by use of matching angles on the interior of the moving member and the exterior of the stationary member. As a result, operation of the plug is fully balanced with the internal fluid pressure of the liquid therein. The sealing surface of the stationary member is positively retained therein to prevent blowout of the sealing surface. Should failure of the sealing surface occur, a secondary metal-to-metal seal will provide fluid containment albeit possibly at a reduced containment level.

Abstract: A skirt guided control valve provides streamlined flow and minimum resistance to flow in flow up and flow down conditions when the valve is open. The skirt guided control valve has a fluid inlet, a fluid outlet, a passageway disposed between the fluid inlet and fluid outlet, a valve seat and a valve plug with a skirt. The valve seat and the skirt portion of the valve plug include blended edges and contoured surfaces to provide for streamlined flow.

Abstract: An essentially fully balanced plug valve is presented in which the flow control contour is interior to the moving member. The sealing edge of the moving member is at the exterior surface relative to the interior contour. This sealing edge is formed by use of matching angles on the interior of the moving member and the exterior of the stationary member. As a result, operation of the plug is fully balanced with the internal fluid pressure of the liquid therein. The sealing surface of the stationary member is positively retained therein to prevent blowout of the sealing surface. Should failure of the sealing surface occur, a secondary metal-to-metal seal will provide fluid containment albeit possibly at a reduced containment level.

Abstract: In an oil flow control valve (OCV) according to the present invention, a first volume varying chamber is adapted to communicate with a second volume varying chamber through a second plunger breathing path, and the second volume varying chamber is adapted to communicate with a first breathing hole through an intra-plunger breathing path, an intra-shaft breathing path, and a third volume varying chamber. That is, the breathing path to the second volume varying chamber is long and the volume thereof is large, and the breathing path to the first volume varying chamber is still longer and larger in its volume. Consequently, the amount of foreign matters getting into the first and second volume varying chambers can be decreased and therefore it is possible to prevent the occurrence of an operation defect of the OCV.

Abstract: A high flow globe valve with a body defining an interior cavity in communication with a first and second fluid passages. A tubular throttling cage is offset in the cavity away from the second fluid passage and has an open end in communication with the first fluid passage. The throttling cage has flow ports angled towards the second fluid passage and the flow port nearest the second fluid passage is oversized. The throttling cage has flow splitter defined by two adjacent flow ports through the cage opposite the second flow passage. A plug is closely received in the throttling cage and moveable to cover the flow ports thereby restricting flow through the throttling cage.

Abstract: This invention relates to a hydraulic valve (10) and an interconnected hydraulic valve system, (10, 12). Two coaxially disposed pipes (14, 20) are positioned vertically to form an annular space (11) there between. A flange (22) provided with a external seal (23) cooperates with an end of the outer pipe (20). Openings (18) formed in the inner pipe (14) regulates water flow. The inner pipe is also sealingly interconnected with a main supply pipe (12) for entry of water through opening (16). An electrical motorized hoist (26) provides for activation and operation of the hydraulic valve system.

Abstract: Apparatus for inducing, impeding, selectively filtering or otherwise effecting fluid flow in microfluidics applications. Opposing mesh layers are placed into relative motion by a variety of motive forces. Fluid between the opposing mesh layers is compressed so as to be pumped through the mesh layers when the relative motion of the layers is toward each other. Mesh layers may also be offset from each other though an actuating force so that one mesh layer blocks the openings in the other mesh layer, thereby creating an impediment to fluid flow. The degree of offset may be varied so as to create a partial impediment to fluid flow, thereby presenting a filter effect.

Abstract: A bleed valve assembly includes a valve poppet having a bleed portion and a base portion separated by a radially extending flange. The radially extending flange is located about the perimeter of the valve poppet to engage the valve seat on one side and receive a biasing member on the other. The flange engages the valve seat such that initial valve performance is similar to a disk valve, i.e., soft seating and very low leakage when closed. A plurality of openings extend through the bleed portion such that partial open operation of the bleed valve assembly is particularly tailored for a desired flow. As the valve poppet of the present invention moves off the valve seat, the initial gain is very low and then the gain increases steadily as more openings are exposed.

Abstract: A high flow globe valve with a body defining an interior cavity in communication with a first and second fluid passages. A tubular throttling cage is offset in the cavity away from the second fluid passage and has an open end in communication with the first fluid passage. The throttling cage has flow ports angled towards the second fluid passage and the flow port nearest the second fluid passage is oversized. The throttling cage has flow splitter defined by two adjacent flow ports through the cage opposite the second flow passage. A plug is closely received in the throttling cage and moveable to cover the flow ports thereby restricting flow through the throttling cage.

Abstract: A damper including a pair of damper members movable with respect to each other is disclosed. Each damper member has at least one wall correspondingly inclined to an axis of the damper. The inclined walls are relatively movable between open and closed positions. The walls include plural apertures separated by imperforate portions. The apertures in each wall are disposed such that the apertures of one of the damper members are at least partially blocked by the imperforate portions of the other damper member when the inclined walls are in the closed position.

Abstract: There is a balanced plug valve with a contour shaped wall. The contour shaped wall forms a gap with an edge of a balanced plug. Fluid is able to flow through an input port, through the balanced plug, through the gap, and out an output port. The shape of the contour and the relative position of the balanced plug to the contour shaped wall affect the modulation of the rate of the fluid flow through the gap, and thus, through the valve. Multiple possible variations of the dimensions of the contour shaped wall make possible a multitude of flow rate verses valve stroke relationships. Further, the use of a balanced valve decreases friction forces on the plug which allows for smaller, more efficient, and more economical valve actuators.

Abstract: There is a balanced plug valve with a contour shaped wall. The contour shaped wall forms a gap with an edge of a balanced plug. Fluid is able to flow through an input port, through the balanced plug, through the gap, and out an output port. The shape of the contour and the relative position of the balanced plug to the contour shaped wall affect the modulation of the rate of the fluid flow through the gap, and thus, through the valve. Multiple possible variations of the dimensions of the contour shaped wall make possible a multitude of flow rate verses valve stroke relationships. Further, the use of a balanced valve decreases friction forces on the plug which allows for smaller, more efficient, and more economical valve actuators.

Abstract: A spool valve is provided with a stem portion that defines a fluid passageway formed by either (a) a single central support having a non-cylindrical curved surface shaped hydrodynamically, or (b) only a pair of sidewalls with, preferably, interior surfaces that are also shaped hydrodynamically. These stem passageways, which are designed to facilitate the flow of high-speed/high-pressure fluids controlled by the valve, are maintained in a predetermined orientation relative to the ports of the valve cylinders by a mechanism preferably including (a) a cam-following roller supported in a tang fixed to each spool and (b) a two-element cam that captures the roller within two of the parallel sides of a cam-track groove formed on the respective interior surfaces of each cam element.