Abstract: A technique facilitates actuation of a downhole device, e.g. a flow control valve. The downhole device is shifted between positions by an actuator piston, which is movable in a first direction via hydraulic actuating fluid supplied by a first control line and in a second direction via hydraulic actuating fluid supplied by a second control line. A hydraulic circuit is coupled between the first control line and the second control line to enable a complete stroke of the actuator piston in one direction, e.g. the second direction, while limiting movement of the actuator piston to incremental movements in the other direction, e.g. the first direction. The hydraulic circuit employs a hydraulic enabled regulator having a plurality of pistons arranged to control the supply of hydraulic actuating fluid to achieve the desired incremental movements of the actuator piston.

Abstract: A valve assembly of a fuel supply system includes a first body defining a first bore, an inlet port to receive fuel into the first bore, and an outlet port. The valve assembly further includes a pneumatic chamber disposed in fluid communication with the first bore. The valve assembly further includes a first piston to move between a first position and a second position. The first piston restricts and allows flow of fuel from the inlet port to the outlet port, in the first position and the second position, respectively. The valve assembly further includes a vent passage located upstream of the pneumatic chamber and configured to receive fuel leaked from a flow path defined between the inlet port and the outlet port. The valve assembly also includes a check valve disposed in the vent passage and configured to selectively vent the fuel entering the vent passage.

Abstract: Linear clutches for reducing axial loads in a system are provided. In one embodiment, a system includes a blowout preventer having a ram coupled to an actuation assembly. A locking assembly is positioned within the system to enable an end of the locking sleeve to engage the actuation assembly and to lock the actuation assembly and the ram into place. In this embodiment, the locking sleeve is segmented and includes at least one groove to engage a complementary surface of the actuation assembly. Additional systems, devices, and methods are also disclosed.

Abstract: A valve actuator apparatus and method for adjusting for valve bore drift using an adjustable downstop is disclosed. The adjustable downstop comprises a downstop and a drift adjuster. The drift adjuster can me moved in an upwards or downwards direction to increase or decrease the stroke length of the operator shaft.

Abstract: A pressure and flow altitude compensated shut off valve includes a valve body, a valve element, and an altitude compensation pilot valve. The valve body has an inlet port, an outlet port, and a flow passage extending between the inlet port and the outlet port. The valve element is disposed within the flow passage and is responsive to fluid pressure at the inlet port to move between a closed position, in which fluid may not flow through the flow passage, and a plurality of open position between the closed position and a full-open position. The altitude compensation pilot valve is coupled to the valve body and is responsive to pressure variations at the second port to control the fluid pressure at which the valve element moves to the closed and open positions.

Abstract: In a valve system or method, an actuator is provided with an actuating rod. A valve is actuated by the rod and has a valve stem and a valve member secured thereto. A travel limiting device defines a travel limit of the actuating rod. A setting mechanism sets the travel limit. The actuating rod and valve stem are decouplable from each other. The setting mechanism comprises a connector for coupling the actuating rod and the valve stem, the connector being designed to set an axial spacing between the actuating rod and the valve stem.

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 control valve having an external valve trim adjustor is provided. The control valve comprises a valve shaft comprising a contact member extending in a direction transverse to the valve shaft, a stationary valve cap adapted to receive the valve shaft, an adjustment member coupled to the valve cap, and a stop plate coupled to the contact member and threadedly coupled to the adjustment member, the stop plate positioned at least partially between the adjustment member and the contact member and adapted to position the contact member away from the valve cap in response to manipulation of the adjustment member.

Abstract: The disclosure relates to a method for commissioning pneumatically operated actuators that are controlled by a positioner. To determine the drive type, a constant flow of pneumatic fluid is applied to the actuator during commissioning while a drive-specific characteristic curve of the fed back position is recorded over time. Then the measured characteristic curve is compared with a given specimen characteristic curve. The drive type is inferred from the level of difference or agreement between the drive-specific characteristic curve and the specimen characteristic curve.

Abstract: A normally-closed valve having a microflow rate adjusting device includes a valve stem for opening and closing a fluid passage; a biasing device for biasing the valve stem in a direction to close the fluid passage; a piston body which is engaged in a cylinder in an air-tight manner to form a pressure chamber for moving the valve stem in a valve opening direction against the biasing device; and a stopper mechanism, provided on the cylinder, for controlling a limit of movement of the piston body in the valve opening direction. The stopper mechanism comprises a stroke adjustment member which is screw-engaged with the cylinder coaxially with the valve stem so that a position of the stroke adjustment member relative to the cylinder can be adjusted, and includes an annular tapered surface at an end of the stroke adjustment member which faces the piston body.

Abstract: An actuated valve having a rotatable cam that controls an opening and closing disc and stop members for the cam, the cam having a notch that allows the cam to be stopped between fully open and fully closed, and an adjustable member on the stop member that corresponds with the notch that allows the cam to be rotated to the fully open or fully closed position. A method of thermally cracking at least one of whole crude oil and natural gas condensate using the actuated value.

Abstract: A normally-closed valve having a microflow rate adjusting device includes a valve stem for opening and closing a fluid passage; a biasing device for biasing the valve stem in a direction to close the fluid passage; a piston body which is engaged in a cylinder in an air-tight manner to form a pressure chamber for moving the valve stem in a valve opening direction against the biasing device; and a stopper mechanism, provided on the cylinder, for controlling a limit of movement of the piston body in the valve opening direction. The stopper mechanism comprises a stroke adjustment member which is screw-engaged with the cylinder coaxially with the valve stem so that a position of the stroke adjustment member relative to the cylinder can be adjusted, and includes an annular tapered surface at an end of the stroke adjustment member which faces the piston body.

Abstract: A valve with a flow adjustment device in the form of a valve stem travel limiter includes a removable and reversible collar having a passage therethrough to receive a valve stem having a shoulder, the passage further includes two bores having different diameters. The flow adjustment device may be assembled to a valve stem to permit two different predetermined valve stem travel limits.

Abstract: A self-contained non-liquid contacting relief valve adjusting device is easily disassembled from a relief valve preferably by removing a clamp band without the use of wrenches or special tools and separating the device from the relief valve. The adjusting device retains the preset relief valve adjustment when removed, and eliminates the requirement for readjustment of the relief valve by retaining the spring compression in the adjusting device. This feature enables the relief valve adjusting device to be set one time and to retain that setting throughout the life of the relief valve regardless of how many times the relief valve is disassembled for cleaning.

Abstract: A combined valve is constructed by integrating a manual valve operating as a safety mechanism and a pilot valve. When a handle of a knob of the manual valve is in a safety mechanism release position, a valve mechanism can be opened and closed depending on whether or not there is air supply to an operation port. When the handle is in the safety mechanism release position and the valve mechanism is even in a valve open state, the valve mechanism can be forcibly brought to a valve closed state by rotating the handle to a safety mechanism set position. Further, when the handle is in the safety mechanism set position, the valve mechanism can always be kept in the valve closed state irrespective of air supply to the operation port.

Abstract: A flow control device comprises an inlet port through which fluid is supplied, an outlet port through which the fluid is delivered, a valve body which is arranged in a passage between the inlet port and the outlet port so as to open and close the passage, the flow control device further comprising a valve body guide means which urges downwardly and pulls upwardly the valve body so as to allow the fluid in the passage to flow at a flow rate which is lower than a basic control rate of the flow control device.

Abstract: A first piston and a second piston are accommodated in a piston chamber of a cylinder. The first piston is connected to a main valve member which opens and closes a main flow passage. The second piston is connected to a second rod having a stopper whose position can be adjusted. Pressure fluid is supplied to the second pressure chamber to move the second piston forward to a position where the stopper abuts against the abutting portion. In this state, pressure fluid is supplied to the first pressure chamber to move the first piston to a position where the first piston abuts against the second piston, thereby opening the main valve member by a stroke of the first piston.

Abstract: Disclosed is system for controlling a dynamic hydraulic component, such as a hydraulic actuator or motor. The system allows for either zero, restricted or full fluid flow to the hydraulic component. This enables either no movement, slow, precise movements, or rapid, major movements of the component. The-functionality of the system is accomplished using a multi-pilot system acting on a spool valve that has a pilot piston and at least one stop piston. The stop piston(s) can move to limit the movement of the pilot piston.

Abstract: The present invention is related to valves for the controlling the flow of media. For example, the valves of the present invention may control the flow of solid media into a fluid stream. More, specifically, the valves of the present invention may be used to control the flow of a blasting media into an air stream as part of a blasting apparatus for treatment of a surface. In one embodiment, the media control valve of the present invention includes a valve body having a media inlet and a media outlet. A housing is connected to the valve body. A plunger is positioned within the valve body and is connected to a piston positioned within the housing. A base is connected to the valve body such that it communicates with the media outlet. The media control valve of this embodiment may further include a sleeve disposed between the valve body and the plunger. This sleeve may contain a media opening.

Abstract: Disclosed is system for controlling a dynamic hydraulic component, such as a hydraulic actuator or motor. The system allows for either zero, restricted or full fluid flow to the hydraulic component. This enables either no movement, slow, precise movements, or rapid, major movements of the component. The functionality of the system is accomplished using a multi-pilot system acting on a spool valve that has a pilot piston and at least one stop piston. The stop piston(s) can move to limit the movement of the pilot piston.

Abstract: A hydraulically operated fluid metering apparatus provides discharge of a known volume of fluid to an actuator of a well tool. In one described embodiment, the fluid metering apparatus is connected to a hydraulic input of a well tool actuator. Discharge of the known volume of fluid to the actuator input causes a piston of the actuator to displace a known distance, thereby producing a known increment of actuation of the well tool. The discharge of the known volume of fluid may be repeated to produce a desired total degree of actuation of the well tool.

Abstract: A valve includes a fluid inlet passage having a fluid inlet, a fluid outlet passage, an orifice between the fluid inlet passage and the fluid outlet, and a moveable valve plug adapted to move with respect to the orifice to vary the flow of fluid between the fluid inlet passage and the fluid outlet passage. A movable valve stem is attached to the valve plug and a travel limiting device is attached to the valve stem. The travel limiting device permits the valve to be placed in one of a plurality of desired flow configurations.

Abstract: By depressing a push button (13), a user deforms a flexible diaphragm (30) and thereby causes an incompressible fluid to flow from a first actuation-chamber segment (42) through openings (48) in a divider wall (46) and into a second chamber segment (44). That flow deforms a second flexible diaphragm (40), which accordingly causes an actuator shaft (58) to break the seal formed by an O-ring (57) and thereby permit flow from a main valve inlet (11) through a main valve outlet (12). When the user releases the push button (13), an actuator check valve (50) prevents the incompressible fluid from returning through the divider-wall openings (48) to the first chamber segment (42). The actuator therefore returns only slowly, through a bleed orifice (72). A pressurizer conduit (86) communicates the valve's outlet pressure to a stop chamber (82) and thereby causes the position of a stop member (76) to be dependent on that pressure.

Abstract: Apparatus for operating a closure for an aperture of a material storage container has a device to regulate the position of the closure relative to the aperture, so that an annular gap through which material is discharged is adjustable to prevent crushing of material which might be “bridged” in the gap.

Abstract: In producing a semiconductor device by annealing with laser light irradiation, while a linear laser light is scanned in a direction perpendicular to a line, the annealing is performed for a semiconductor material. In this state, since an anneal effect in a beam lateral direction corresponding to a line direction is 2 times or more different than that in the scanning direction, a plurality of semiconductor elements are formed along a line direction in which the linear laser light is irradiated. Also, a line direction connecting the source and drain region of a thin film transistor is aligned to the line direction of the linear laser light.

Abstract: A diaphragm valve includes a valve housing, a diaphragm assembly mounted within the valve housing, a pilot valve coupled to the valve housing and a flow control stem mounted in an upper bonnet of the valve housing. The valve housing has an inlet passage and an outlet passage. The diaphragm assembly is vertically reciprocable back and forth within the valve housing to thereby connect and disconnect the inlet passage and the outlet passage. The valve housing has a lower inlet chamber below the diaphragm assembly, an upper pressure control chamber above the diaphragm assembly, and a bore in the bonnet which communicates with the upper pressure control chamber. The pilot valve is operatively associated with the upper pressure control chamber for selectively venting pressurized liquid therefrom.

Abstract: A rotary valve actuator with movable actuator linkage maintained in a constant "pull-pull" tension, includes a sliding canister, rotatable lever, and a return spring substantially aligned in-line with each other. The linear motion of the canister in response to an expanding and contracting pressurized bladder is converted through chain linkage into rotary lever motion. The return spring is connected through respective chain linkage to the lever so the pulling tension of the spring/lever linkage rotates the lever and maintains tension on both chain linkages. Adjustable travel stops are provided. In an alternate embodiment the return spring chain linkage is configured at right angles to the linear movement of the canister. A double acting rotary valve actuator with pressurized bladders on opposite sides of a rotatable lever. One bladder is oval shaped.

Abstract: A rotary valve actuator with movable actuator linkage maintained in a constant "pull-pull" tension, includes a sliding canister, rotatable lever, and a return spring substantially aligned in-line with each other. The linear motion of the canister in response to an expanding and contracting pressurized bladder is converted through chain linkage into rotary lever motion. The return spring is connected through respective chain linkage to the lever so the pulling tension of the spring/lever linkage rotates the lever and maintains tension on both chain linkages. Adjustable travel stops are provided. In an alternate embodiment the return spring chain linkage is configured at right angles to the linear movement of the canister.

Abstract: To reduce the axial length of a slow exhaust valve and thus the size of the valve, a secondary valve seat and a secondary valve body constituting a secondary valve mechanism for restrictively opening a channel connecting a chamber port and a pump port during the first half of the exhaust process in order to limit the exhaust speed are incorporated in a primary valve body in a primary valve mechanism; a secondary-valve-body drive mechanism and a pressure-acting secondary chamber are incorporated inside a primary-valve-body drive member in the primary valve mechanism; and a secondary shaft that connects the secondary valve body and the secondary-valve-body drive member together is disposed inside a primary shaft.

Abstract: A high-pressure valve comprising a piston whose upper surface is acted upon intermittently by a medium, such as air, to control vertical movement of the piston, the valve including a connection of the piston to a needle valve. The needle valve coacts with a valve seat and communicates with the inlet to a liquid delivery line through which liquid is delivered to the needle valve via a high-pressure pump and leaves through a nozzle orifice. Also provided is a rotatable device for mechanically forcing the piston to a lower position in which the needle valve is brought into abutment with the valve seat.

Abstract: A transition valve for a hydraulic elevator includes a block, a spool, an actuator, and an end cap. The actuator may be either a solenoid type actuator or an electric motor type actuator. The end cap includes an opening permitting engagement between the actuator and the spool. In a particular embodiment, the actuator is an electric motor engaged with the spool via a crank and arm. This arrangement translates the rotational motion of the motor into linear motion of the spool with a sine curve profile.

Abstract: The invention is a flow control for a ventilation duct. It includes a movable panel which is attached to a variable volume reservoir. The application of vacuum to the reservoir controls the angular position of the door and the volume of the reservoir.

Abstract: A valve assembly for a pneumatic machine including a valve body having a first end, a second end, a central bore extending through the ends and a plurality of flow ports formed in the body; a valve spool movable through the bore along an axis in response to the flow of gas through the valve, to selectively open and seal the ports; an main inlet valve for moving the valve spool a distance along the axis; and a manually actuated means for overriding the main inlet valve.

Abstract: A slow vent valve for semiconductor wafer manufacturing equipment is disclosed, which generates a gentle flow of nitrogen gas to the vacuum chamber enough to maintain an undisturbed ambient environment for the wafer being processed in the chamber, protecting the product from disturbed by particulate raised or objectionable ambient stirring caused by the entering gas. The valve includes an adjustable cam mechanism including a valve open timing adjuster and a slow-venting adjuster. The valve open timing adjuster changes the initial diaphragm pressing force on the valve seat, to thereby determine the open speed and the open timing of the valve to take a lift off the valve seat. The slow venting adjuster is provided to adjust the resistance of a spring that exerts downward pressure on a second piston integrated with the valve rod, to thereby slow the slightly upward movement of the rod to operate the diaphragm to permit a slowed flow of nitrogen gas to the vacuum chamber.

Abstract: An apparatus is provided which includes a valve transmission designed to connect a valve actuator to a rotational valve. The valve transmission includes a pinion, a pair of stepped racks, and a lower gear, all within a housing. The pinion is designed to be driven by a rotating shaft of an actuator. The pinion engages the teeth of the racks on the upper steps. The lower steps of the rack are displaced laterally from the upper steps to engage a lower gear that is either of lesser or greater diameter than the pinion depending on whether a positive or negative mechanical advantage is desired. The lower steps drive the lower gear which is connected to the drive shaft of a rotational valve. The transmission is placed within a housing which removeably mounts to the valve body.

Abstract: A locking mechanism for an actuator prevents the unauthorized operation of the actuator and also permits a viewer to determine whether the actuator is in a locked open, locked closed or unlocked position. The invention utilizes a clear cover guard which is positioned and locked on an actuator body which is attached to a housing. The actuator body comprises threaded bores which permit a bolt to be inserted into the actuator body until it contacts an integral locking cam and driver arm rotatably disposed within the actuator body. The bolt contacts the locking cam in order to selectively lock the integral locking cam and driver arm in a desired position.

Abstract: The invention discloses a controlled connector-adjuster permitting two different speeds in the same stroke of a double-acting pneumatic pressure cylinder.In the absence of a control signal at the orifice (13) of the apparatus, the escape pressure from the cylinder (30) effecting its rod extension stroke, finds the return valve (14) closed and holds the piston (2) against the stop (9) whose adjustment defines a first flowrate between the needle valve (15) at the end of the piston and its seat (16), which flowrate corresponds to the high speed. The arrival of a pressure signal into the chamber (6) causes piston (2) to move until it abuts on a second screw (7) whose adjustment permits a second smaller flowrate than the first one and which thus determines the second speed.

Abstract: Metering valve assembly having a poppet movable relative to a valve seat for controlling communication through an orifice. The poppet is urged toward the valve seat with a closing force, and the poppet can be adjusted gradually to provide a fine adjustment of the communication through the orifice. An actuator is operably connected to the poppet to overcome the closing force and move the poppet rapidly to a preset position. When the actuator is not actuated the closing force urges the poppet toward the valve seat to provide a positive shut-off.

Abstract: An adjustable flow applicator includes a body having an axial flow pasasge and an inlet passage adapted for connection to a source of pressurized fluidic material dispensed by a positive displacement constant flow rate dispenser. A nozzle is connected to the body and communicates with the flow passage and has an orifice. A reciprocal piston rod extension is spaced within the flow passage and terminates in a tapered valve member having an advanced position seated within the orifice to shut off flow of fluidic material and first and second retracted positions variably opening the orifice for reduced flow in a first position and higher flow in a second position. First remote control includes a first piston connected to the piston extension for effecting alternate reciprocal movements of the valve member for alternately opening and closing the orifice.

Abstract: An improved liquid dispensing apparatus having a micro-adjustment of the opening travel of a needle valve of the apparatus. This micro-adjustment comprises a sleeve-stop member which is axially movable but non-rotatable in the body of the apparatus. One end of the sleeve-stop member forms an end-stop to limit opening movement of the needle valve away from the valve seat. Screw threads of a first pitch are formed on an external portion of the sleeve-stop member and internal screw threads of a second pitch different from the first pitch are formed on a portion of the apparatus body. A generally tubular adjustment screw element is engaged with both the internal scew threads of the body bore and the external screw threads of the sleeve-stop member so that rotation of the adjustment screw element causes differential axial movement of the sleeve-stop member for fine adjustment of the maximum opening needle valve travel.

Abstract: A rotary actuator for a damper shaft controls the angular position of the damper shaft in accordance with variations in fluid pressure inside of the actuator. The actuator includes a housing, a flexible diaphragm within the housing separating it into a fluid-tight compartment and a second compartment open to the atmosphere. The fluid-tight compartment is provided with a fluid pressure receving port open to a control source of variable pressure. The piston and piston rod are slidably mounted in the second compartment in contact with the diaphragm. The piston rod includes a longitudinally extending rack, and a crank arm rotatably mounted in the housing has a gear segment in meshing relationship with the rack. The actuator shaft to be controlled extends through the housing and is mounted in the crank arm to support the rotary actuator, and the rotary actuator is clipped to an air conditioning duct to prevent it from rotating on the damper actuator shaft axis.

Abstract: A flow control valve in which the main body of the valve and the first and the second cylinder is disposed coaxially with each other. The valve body disposed in the main body forms a first and a second separate chamber in the main body. A first and a second valve rod projecting from the valve body opposes the first and the second cylinder, respectively. The displacements of the pistons in the first and the second cylinder due to a fluid limits the displacement of the valve rods and the valve body. The opening and the closing of the passageway between the first and the second separate chamber is adjusted by the movement of the valve body, thereby flow of fluid being controlled.

Abstract: A variable flow rate valve (10) comprising; a housing (12) defining a vacuum chamber (35) and a flexible diaphragm (50) secured to said housing (12). The diaphragm defines one extreme of the pressure chamber (35) and is movable in one direction in response to decreases in the pressure within the pressure chamber and movable in an opposite direction in response to increases in the pressure within the pressure chamber. The valve (10) further includes means (40, 100, 110, 112) for providing a mechanical position limit or stop for the diaphragm in the one direction and means (126, 84, 86, 92, 94) for selectively varying the pressure within the pressure chamber for causing the diaphragm to move in response to the pressure differential thereacross.

Abstract: A valve actuator for providing rotational drive to a valve through a valve stem, where the valve includes a flange with attachment bolt holes for attachment of the actuator thereto using bolts. The actuator has an outer body having a sidewall and a base end position toward the valve flange, a rotatable output drive member accessible from the base end and adapted for coupling to the valve stem and having rotational end limits, and an attachment base fixedly attached to the body toward the base end and having a base flange and an attachment lip. The lip is attached to the base flange and is spaced apart from the body sidewall to define an annular space therebetween. A plurality of clips are positioned about the lip to secure the body to the valve flange while allowing selective rotation of the body to adjustably set the rotational end limits of the output drive member relative to the valve.

Abstract: A solenoid-operated pilot valve of the diaphragm type which includes an assembly for controlling the flow of liquid through the valve. The valve has particular although not exclusive utility for irrigation purposes. The valve includes a diaphragm chamber into which fluid is introduced to establish a fluid pressure which normally forces a diaphragm against an annular seat in the valve to assist a spring in maintaining the valve in a closed condition. A stationary bleed tube is provided which extends through the diaphragm into the diaphragm chamber. A solenoid is mounted on the cap of the valve, and the plunger of the solenoid normally closes off the upper end of the bleed tube. However, when the solenoid is energized, the plunger is withdrawn and the bleed tube opens and drains the diaphragm chamber sufficiently to reduce the pressure therein to a point at which the diaphragm is forced off its seat by upstream fluid pressure, and the valve is opened.

Abstract: A combination valve for relieving excess pressure while also stopping downstream gas flow. A pull-type valve core is mounted within the gas flow passage of a valve body. It includes an actuating plunger operatively connected to a poppet that overlies the valve core and sealingly reciprocates against an upper portion of the valve body. The poppet includes a head portion with a central orifice. The poppet seats against an inner surface of a vented housing which encloses the poppet, valve core and valve body. A spring biases the poppet to its seated position allowing normal gas flow through the central orifice and valve core. Excessive gas pressure will overcome the spring force and allow the excess to vent out the housing. Unseating of the poppet also allows the actuating plunger to close the valve core and stop gas flow to downstream equipment.

Abstract: A positioning apparatus using a hydraulic actuator. For positioning an object to the desired position with high accuracy, the apparatus has means for computing the position at which the operation for stopping the operation of the hydraulic actuator is to be carried out in order to position the object at the desired position. The operation of the hydraulic cylinder is rendered to stop when the position has reached the computed position, whereby to enable the object to accurately position at the desired position at relatively high speed.

Abstract: An air operated oil pressure control valve wherein the inlet port and the outlet port for oil are provided in the valve body at a position wherein they face each other with a normally closed valve port located in between. When compressed air is introduced into the valve body, the valve port is opened, allowing the oil pressure to pass through the valve.

Abstract: The invention provides an automatic exhaust brake valve unit having a hollow body with an exhaust gas passage extending therethrough and a valve closure member movable in the hollow body between a closed position in which it closes the passage, and an open position in which it leaves the passage clear, the hollow body having an open end face closed by a removable plate so that the valve closure member can be removed through that end face. Such a valve unit is usable to control exhaust gas flow in either direction through the exhaust gas passage when connected in an exhaust system of a motor vehicle.

Abstract: An actuator for a rotary valve preferably embodying a diaphragm motor operated by pressure fluid. A driving sleeve is reciprocated linearly by the diaphragm motor and within said sleeve is a rotatable shaft, which is axially aligned with the diaphragm motor and driven by a ball screw. A driven sleeve is fixed to said shaft and receives the stem of the valve. All parts are in linear alignment. Means are provided for limiting the extent of the linear movement of the parts.