Abstract: A CVD reactor includes a gas-tight and evacuatable reactor housing and an inner housing arranged therein. The inner housing has means for the infeed of a process gas and means for holding a substrate for treatment in the inner housing by means of the process gases. The inner housing also has a loading opening which can be closed off by a sealing element of a closure element. In its closure position, the closure element bears with an encircling sealing zone against a counterpart sealing zone which encircles the loading opening on the outer side of the inner housing. The sealing element is fastened to a carrier as to be adjustable in terms of inclination and/or pivotally movable about at least one spatial axis (X, Y, Z) and/or so as to be elastically deflectable in the direction of one of the spatial axes (X, Y, Z).

Abstract: The present invention discloses a gate valve with a first side and a second side relative the throughbore. A circular body cavity is on the first side and a rectangular body cavity on the second side and a portion of the first side whereby the gate is operable to move up and down within the body cavities. Due to the rectangular body cavity, the seats are slimmer than the gate. A skirt assembly is used which is inserted over the gate to cover the gate opening when the gate is moved to the closed position to prevent debris and other contaminants from entering the body cavity. Four U-shaped seals are mounted to provide that the gate valve is a bidirectional gate valve with upstream sealing having back up downstream sealing in case an upstream seal fails.

Abstract: A gate valve and gate member for a gate valve, which may be used for hydrocarbon well fracturing operations with a fracturing fluid, or “frac fluid”, includes a seat, having a seat end face which is in sliding contact with a gate member that has a sealing face surface with at least one recess formed in the sealing face surface of the gate member.

Abstract: A tensioning device, including a base configured to carry a mask plate, a clamp configured to clamp the mask plate, and a deformation adjusting assembly provided on the base or on the clamp, wherein the deformation adjusting assembly is configured to adjust a deformation of an end portion of the mask plate protruding from the base in a direction of gravity when the base carries the mask plate, so as to make the deformation less than a preset deformation threshold. A base, a clamp and a clamping for the mask plate are also provided.

Abstract: In an embodiment, a gate valve includes a valve body including a first opening, a second opening, a flow passage from the first opening to the second opening, and a gate channel intersecting the flow passage. The gate channel is defined in part by two side walls facing parallel to a center axis of the flow passage, and wherein at least one of the side walls has a concave slot extending lengthwise along a center of the side wall. In an embodiment, gate for a gate valve includes a first disc-shaped side and a second disc-shaped side. The first disc-shaped side includes a first center guide and a first diameter, the first center guide being a convex ridge extending across the first diameter.

Abstract: A selection valve for a beverage preparation machine comprises a valve body with a hot water inlet, an air inlet, and at least a first outlet. A selector member is movably mounted relative to the valve body for movement between a first position in which the hot water inlet is in fluid communication with the at least first outlet, and a second position in which both the hot water inlet and the air inlet are in fluid communication with the at least first outlet. A satellite element has a predefined limited amount of free relative movement relative to the selector member for allowing the satellite element to be independently positioned between the first and second positions of the selector member.

Abstract: A soft seat knife plate type valve is provided with an opening and closing plate to be inserted into a packing. First sealing structures are continuously formed on the packing, and second sealing structures are continuously formed on an edge of the opening and closing plate. The first sealing structures and the second sealing structures are complementary to each other to be removably coupled to each other.

Abstract: A gate valve having a seat plate with a recessed face smaller in width than a bore of the valve. The recessed face includes an opening, which can be generally rectangular for use of the valve as a substantially linear control valve. The valve closes by movement of the gate along the recessed face to obstruct the opening, and opens by the reverse movement.

Abstract: A gate valve for use in controlling the level of a dam has a first plate with an aperture on an upstream face of the dam and a movable plate on the upstream side of the fixed plate, with apertures sixed and dimensioned to operate as a scissors when the movable plate is urged in a linear motion parallel to fixed plate. One or more edges of the apertures in the plates are provided with a sharp edge or a serrate edge oriented to sever obstructing object present in the apertures when the valve is transitioning from an open position to a closed position.

Abstract: Gate valve including a valve body having first and second parts, each having an interface surface for engagement with the interface surface of the other part, and an aperture for receiving a fluid flow conduit. The parts when secured together define a gate recess and a flow conduit between the apertures. A gate in the recess moves between closed and open positions to control fluid flow through the gate. A valve body insert lines interior surfaces of the gate recess and receives the valve gate. A body portion sits between apertures of the two parts, sealing against the gate in a closed position. A gate wiper seal forms a fluid seal against the gate and an outer open end of the sleeve portion. The two parts have a recess portion at a gate recess end. The sleeve portion has a collar portion sealingly seated within the recess portion.

Abstract: A valve has a housing defining an inlet and an outlet and a cavity therebetween which receives a valve seat. The valve seat defines a slot which receives a gate. The valve seat is sealingly engaged with the housing, the gate sealingly engages the valve seat and is movable within the slot between an open and a closed position using an actuator. An opening in the housing provides access to the cavity. The valve seat may be removed from the housing through the opening by attaching the valve seat to the gate, thereby attaching the valve seat to the actuator, and withdrawing the gate from the housing using the actuator.

Abstract: A ram assembly is disclosed. The ram assembly includes a ram wedge, a blade, and a ram seat. The ram wedge has a tubular cavity therethrough for receiving the tubular. The ram wedge is slidably positionable in the ram channel between a retracted and an extended position, and has rails extending therefrom. The blade is positionable about the tubular cavity, the blade carried by the ram wedge to cuttingly engage the tubular. The ram seat is positionable in the housing about the passage, and has a hole for receiving the tubular therethrough. The ram seat also has an outer surface interlockingly engageable with the rails as the ram wedge moves relative thereto whereby a gap is reduced therebetween.

Abstract: A water valve and a pool are provided. The water valve includes a valve body having a first channel; and a valve plate having a valve plate opening and configured to control opening or closing of the first channel by sliding; when the valve plate is in a first position, the valve plate opening is aligned with the first channel and water can flow through the first channel, the water valve is opened; when the valve plate is in a second position, the first channel is blocked by the valve plate, the water valve is closed. The pool includes a water inlet part connected with a pool wall and the water valve detachably connected with the water inlet part. The water valve is simple in operation, has good sealing performance and switch function of the water valve and disinfection function of the chemical dispenser, thereby improving the water valve's performance.

Abstract: A closure device for the vacuum-tight closure of an opening includes a closure element, at least one rod that projects out of a housing of the closure device and that, outside the housing, supports the closure element and that is rigidly connected to a carrier piece, a transmission unit which is adjustable by a drive parallel to the longitudinal adjustment direction between an initial, open position of the closure element, a middle position, in which the closure element assumes the intermediate position, and a closed, end position. At least one spring is arranged between the transmission unit on the carrier piece, and a stop device which, during adjustment of the transmission unit from the middle to the end position, blocks a further adjustment of the carrier piece parallel to the longitudinal adjustment direction.

Abstract: An actuating device or displacing a control device, such as a valve, gate valve or other control mechanism, in particular for use in oil or gas production systems, comprises a motor-gear unit (21) and a thread drive (22) which is operable by said motor-gear unit (21) and which comprises at least a threaded spindle (23) and a screw nut (24). The threaded spindle (23) is displaceable in an essentially axial direction so as to displace the control device (2) between a use position (7) and a non-use position (8, 9, 19, 20). To ensure a safe displacement into the non-use position in a simple way and independently of the pressure conditions prevailing between conveying medium and inner medium, the threaded spindle (23) is substantially axially displaceable beyond the use position (7) into a second non-use position (9). The invention also refers to a corresponding method for displacing the actuating device.

Abstract: The invention provides a gate valve for control of production of petroleum, distinctive in that the valve comprises a coating or hard facing on the internal bore surface exposed to flow of petroleum and associated fluids and solids.

Abstract: This invention relates to a valve for metering filled and/or pasty media. In accordance with an embodiment, the valve comprises a valve element having a metering opening and a valve gate movable in translation and having a flow opening. The valve gate is configured for carrying out an oscillating double-stroke movement in the course of which the flow opening of the valve gate is temporarily aligned with the metering opening of the valve element. The flow opening of the valve gate is aligned with the metering opening of the valve element in the course of the double-stroke movement of the valve gate a first time during the forward stroke and a second time during the backward stroke.

Abstract: A system for positioning a seal member on a movable valve stem. The system includes an O-ring surrounding a lower portion of a movable valve stem. A snap-on retaining collar is pushed into place along the valve stem. A lower edge of the collar contacts the O-ring. The interaction between the snap-on collar and the O-ring prevents the O-ring from flexing outwardly and becoming dislodged from the valve stem. The snap-on retaining collar can be formed from various materials, such as but not limited to plastic.

Abstract: Methods, systems, and apparatus for a gate valve including a body and a sensing bore. A subassembly includes a body with a sensing bore; a bonnet contacting the body; and at least one of a vein and a plug in the sensing bore.

Abstract: A valve includes a stem seal assembly that prevent fluid flow in a first direction and vents in a second direction opposite the first direction. The assembly includes a packing assembly positioned within a valve stem opening of a valve body of the valve to seal a valve stem to the valve body. The packing assembly includes a first seal and a second seal preventing passage of fluid from a body cavity of the valve body to an exterior of the valve body along the valve stem while venting fluid from an exterior of the valve body to the body cavity along the valve stem. The packing assembly isolates the first seal and the second seal so that a load applied to the first seal ring is not transferred to the second seal ring.

Abstract: A gate valve includes a valve body and a spindle drive. The spindle drive has, at its one end, a wedge for blocking a pipe. The spindle drive includes a motor-driven spindle, wherein, wherein the spindle is connected by way of a coupling to a shaft in an axially displaceable manner, and the shaft has the wedge at its end.

Abstract: An operation for securing and coupling a coupling flange and a fluid device mounted through the interior of a valve case of a sluice valve for operations can be performed with good efficiency from the exterior while sufficiently ensuring the external mounting depth of the coupling tube part on the coupling flange and while facilitating the attachment of pulling and securing means and ensuring the attachment strength.

Abstract: A lock open device for use with a valve in a hydraulic fracturing system, which maintains the valve in an open position. The lock open device includes a plate with beveled edges and spring loaded ball bearings strategically disposed to contact the edges and interfere with axial movement of the plate. The plate couples to a gate member in the valve, so that the interference between the plate and the ball bearings maintains the valve in a designated open or closed position. The angle of the bevel regulates how much force is required to urge the plate past the ball bearings to thereby open/close the valve.

Abstract: A bulk adhesive transfer system for transferring adhesive particulate to a melter includes a bulk supply and a transfer device, which may define a hopper of the melter, a mobile bin, and/or a buffer unit. The transfer device is configured to receive unmelted adhesive particulate from the bulk supply and then be selectively docked with the melter to transfer the adhesive particulate to the melter. The bulk adhesive transfer system may also include a knife gate valve device, which includes a plurality of ports that sequentially open and close to control flow of the adhesive particulate towards the melter. The bulk adhesive transfer system simplifies refilling operations for a melter while enabling continuous operation of the melter, even when the transfer device is undocked for removal from the melter.

Abstract: A slide valve apparatus for automatic application of surface pressure is configured to include a connection switching device (20) for switching a connection position of a drive device (7) and a slide case (4) between a first connection position (discharge position) during molten metal discharge and a second connection position (surface pressure operation position) during surface pressure application/release. As a result, the drive stroke of the drive device can be greatly reduced and the already installed drive device can be used as is when a SV apparatus is upgraded.

Abstract: A piezoelectric valve has a body with an input passage and an output passage each configured to connect to a fluid flow system, a flow control member movable with respect to the valve seat between a fully open position and a closed position and a piezoelectric motor directly connected to the flow control member. The piezoelectric motor has a piezoelectric resonator in which two orthogonal vibrational modes across a length and a width of the piezoelectric resonator are excited, a working element and one or more contact sites providing frictional contact between the working element and the piezoelectric resonator. One of the working element and the piezoelectric resonator is connected to the flow control member and configured to move relative to the other of the working element and the piezoelectric resonator due to the frictional contact, thereby moving the flow control member.

Abstract: A pipe testing fixture including a housing with a chamber, an aperture centrally disposed on the housing. A groove centrally disposed within the lower chamber. A pipe fluidly engages the chamber through the housing. A pipe closure body with a handle slidingly engages the aperture and chamber with a plate disposed on the handle. The plate slidingly engages the chamber, the lower end sealingly engaging the groove, configured to seal the lower chamber of the pipe. A plate face gasket continuously disposed on the front and rear sides of the plate. A locking pin is engagable through a pin hole upon positioning the pin hole outside the upper chamber. The engagement and alternate disengagement of the locking pin through the pin hole places the plate in an open locked position and an alternate closed position within the chamber. A separate carrier pipe segment engages the pipe portions.

Abstract: An actuating device or displacing a control device, such as a valve, gate valve or other control mechanism, in particular for use in oil or gas production systems, comprises a motor-gear unit (21) and a thread drive (22) which is operable by said motor-gear unit (21) and which comprises at least a threaded spindle (23) and a screw nut (24). The threaded spindle (23) is displaceable in an essentially axial direction so as to displace the control device (2) between a use position (7) and a non-use position (8, 9, 19, 20). To ensure a safe displacement into the non-use position in a simple way and independently of the pressure conditions prevailing between conveying medium and inner medium, the threaded spindle (23) is substantially axially displaceable beyond the use position (7) into a second non-use position (9). The invention also refers to a corresponding method for displacing the actuating device.

Abstract: Systems, devices, apparatus, and methods of locking and unlocking a door that is slidable by articulating wheels in tracks, over an entry port to a storm water structure. Locking the door can be accomplished by rotating bolts that are attached to cams. Rotating the bolts causes the cams to press the door against the tracks. Sealing strips can be compressed between door edges and the track to prevent water from passing around the door. A vacuum truck can remove water and debris from the vault/structure. Other versions allow doors to move downward to allow water to overflow the door. The door can slide upward so water can flow underneath. A door in door version has a secondary door slide up and down in tracks in a main door.

Abstract: A system (100) for determining a property of an object (106) comprises an inducing arrangement (102), a detector (104) and a processor. The inducing arrangement (102) is configured to generate an impulse of fluid and for directing the impulse of fluid towards the object to induce a physical vibration of the object (106). The inducing arrangement (102) does not contact the object 106 when inducing the physical vibration of the object (106). The detector (104) is configured to detect the physical vibration of the object (106). The detector (104) does not contact the object 106 when detecting the physical vibration of the object (106). The processor is coupled to the detector (104) for determining the property of the object (106) based on at least the detected physical vibration.

Abstract: The invention provides a gate valve (1) for control of petroleum production or water injection, distinctive in that at least one surface subject to sliding in operation of the valve comprises a top layer coating of diamond like carbon (DLC). The DLC contains hydrogen, preferably more than 16 atom-% and more preferred more than 17 atom-%. It is further directed to a method of commissioning or operating a gate valve according to the invention, and use of a diamond like carbon (DLC) top layer coating on at least one surface subject to sliding in operation of the gate valve. Valve parts have a tendency of sticking, adhering or cold welding together, which result in high friction. The aim of the invention is to reduce or eliminate friction problems occurring with time or operation cycles, when using a full scale gate valve.

Abstract: A valve includes a plug mounted to a lower end of a valve rod for opening or closing a fluid passage in the body. The valve rod extends through a cap and a stretchable jacket. The stretchable jacket includes first and second ends and a deformation section between the first and second ends. The first end of the stretchable jacket is fixed to the cap. The second end of the stretchable jacket is fixed to the valve rod. A stop is located at the deformation section, dividing the stretchable jacket into first and second stretchable sections. A pull rod is fixed to the valve rod or the cap and slideable relative to the stop. First and second positioning members are mounted on the pull rod to limit travel of the pull rod by contacting with the stop, avoiding over stretching and undesired compression of the first or second stretchable section.

Abstract: A sliding screen valve for controlling fluid flow comprises a multi-apertured valve plate (50, 90) configured for sliding movement relative to a multi-apertured valve seat between closed and open configurations and comprises an array of apertures (60, 100) separated from one another by elongate interstitial elements angled at between 15 to 45 degrees from the axis of motion. The valve plate may be operatively connected via an actuator frame (274) controlling its movement to an actuator for sliding movement relative to the valve seat, and may be connected to the actuator via a resilient support element (272) configured to allow a floating movement of the valve plate normal to the valve plate. Initiation or termination of the sliding movement may be damped by at least one damping mechanism. The screen valve may be configured for lateral reciprocating movement and be used in gas compression and/or expansion equipment such as piston compressors or expanders.

Abstract: A non-rising stem gate valve is provided that includes a drive sleeve disposed between the gate and the stem. The drive sleeve is coupled to the stem and isolates the moveable connection between the sleeve and the stem from fluid in the valve. The drive sleeve is also coupled to the gate such that movement of the drive sleeve along the stem moves the gate between the open and closed positions of the valve.

Abstract: A carburetor having an inlet opening that includes a pair of concavities operative to direct air toward the metering rod of the carburetor. A carburetor having an inlet opening that includes an arcuate manifold adjacent to the inlet opening and in fluid communication with a fuel reservoir. A carburetor having a slide assembly that includes a positioning mechanism operative to adjust the position of the metering rod relative to the throttle slide. A throttle slide that includes a flow guide that bisects an arcuate relief on an underside thereof. A method for configuring the throat of a carburetor that includes an upper portion of a first diameter and a lower portion of a second diameter that is offset from the first diameter. The method comprises deriving an optimum size for the first and second diameters and the offset based on the pumping efficiency and operating parameters of the engine.

Abstract: Regulating valve (10) comprising: a body (11) crossed by a channel (12) for a fluid, a shutter (13) sliding in the body (11), according to a sliding direction (A), between a closing position and an opening position. The shutter (13) protrudes along the sliding direction (A) between a back end (16) and a front end (17), which is provided with a side surface (18) parallel to the sliding direction (A) and coupling with the internal surface (15) of the seat (14). The front end (17) is tubular and has at least one aperture (20) crossable by a fluid according to a normal direction to the sliding direction (A). The aperture (20) has two sides (20a, 20b) which join together to form a cuspid and diverge along the sliding direction (A).

Abstract: A sprinkler head includes a sprinkler body formed with a through-bore defining a flow path adapted for alignment with a nozzle bore. A nozzle carrier is mounted on the sprinkler body for linear movement across the flow path and adapted to support plural nozzles. The nozzle carrier is configured to enable any one of the plural nozzles to be aligned with the flow path. The nozzle carrier is provided with plural discrete seal pads that are selectively movable into a position covering the flow path to thereby shut off flow through the sprinkler body.

Abstract: The invention relates to a drive means for a slide valve having two parallel spindles (10) which are driven in rotation by at least one motor (11), travelling nuts (12) which engage the spindles (10) and are movable in the longitudinal direction of the spindles by rotation of the spindles (10), and a cross-yoke (13) which is arranged transversely with respect to the spindles (10) and is connected to the travelling nuts (12) on the one hand and to a rod (14) on the other hand, which rod is arranged in parallel between the spindles (10) and is connected or connectible to a slide plate, the rod (14) being axially movable by the motor (11) for the actuation of the slide plate. It is distinguished by the fact that the travelling nuts (12) and the rod (14) are each articulatedly connected to the cross-yoke (13).

Abstract: The present invention features a coke drum de-heading system. The de-header valve is equipped with a valve body, a gate, a transmission system and an actuator. Actuation of the valve closure functions to open and close the de-header valve.

Abstract: A gate comprising a frame and a blade. The frame defines an opening that is adapted to be opened and closed, and the blade is associated with the frame such that the blade is adapted to open and close the opening. For such purpose, the blade is adapted to move along a path defined by the frame between an open position and a closed position.

Abstract: A high temperature gate valve includes a valve body, a valve element configured to open and close a flow path, and a guide member which is provided in the valve body and guides the valve element in an opening/closing direction. The valve body includes a valve body main portion and a bonnet portion. The valve element slides along the opening/closing direction guided by the guide member. The valve element at a shut-off position blocks the flow path by projecting into the valve body main portion, and at an open position retracts into the bonnet portion. The guide member is divided into a plurality of divided guiding elements along the opening/closing direction, and each of the divided guiding elements are welded to an inside of the valve body.

Abstract: A gate valve system for controlling fluid flow having a valve body with a bore through which fluid can flow. The system includes a valve body having a bore to allow fluid to pass through the valve body and further having a cavity defined by substantially parallel innerside walls of the valve body, a gate wherein at least one end of the gate is defined by a radius perimeter. The system also has a bonnet that is removably coupled to a face of the valve body, wherein a portion of an innerside of the bonnet includes a curved surface adapted to mate with the at least one end of the gate defined by the radius perimeter, and an actuation mechanism operationally positioned and removably connected to the gate by way of a thru-hole in the bonnet.

Abstract: Valves include a valve body having an inner surface and an outer surface, the inner surface and the outer surface defining an inlet, an outlet, and a body cavity between the inlet and the outlet; a gate movably coupled to the valve body and moveable over a portion of the valve body at least partially between the inlet and the outlet, the gate including a cam stop; and a drive assembly, the drive assembly including a drive shaft and a sync cam, the sync cam of the drive assembly movably positioned on the drive shaft and slidably positioned relative to the cam stop.

Abstract: Sleeve valves include a valve body having an inner surface and outer surface, the inner surface and the outer surface defining an inlet, an outlet, and a body cavity between the inlet and the outlet; a sleeve disposed at least partially within the body cavity, the sleeve including at least one opening fluidly connecting the inlet to the outlet; a gate proximate to the sleeve and movable over a portion of the sleeve including the at least one opening, the gate including at least one front stop and at least one back stop connected to the gate; and a drive assembly including at least one drive line having a drive shaft and a sync cam, the sync cam of each at least one drive line movably positioned on the drive shaft and between one of the at least one front stop and one of the at least one back stop.

Abstract: A slide gate comprising: a frame assembly which defines an opening through which fluid flows; a slide plate movably mounted to the frame assembly for vertical movement relative thereto so as to selectively open and close the opening in the frame assembly; an operating mechanism for vertically moving the slide plate between its open and closed positions so as to regulate fluid flow through the opening in the frame assembly, wherein the operating mechanism comprises a threaded operating stem which is secured to the top of the slide plate and which extends through a threaded operating nut which is rotatably mounted to the frame assembly, and means for rotating the threaded operating nut so as to cause longitudinal movement of the threaded operating stem relative to the threaded operating nut, so as to raise or lower the slide plate, whereby to open or close the opening in the slide gate; and a threaded fall-protection nut disposed on the threaded operating stem in spaced relation to the threaded operating nut

Abstract: A seed planter and seed meter for planting different seed varieties based on the location of the machine in a field. A movable gate switches between seed varieties. The gate in one embodiment has three positions; one position opening a first seed passage to the meter and closing a second seed passage, a second position opening the second seed passage and closing the first seed passage and a third position closing both the first and second seed passages. Two other gate embodiments have only two positions, each position opening one seed passage and closing the other.

Abstract: A valve includes a housing, a stern supported by the housing, and a valve member coupled to the stem. The valve member has a first passage defined therein with a metering flow profile, An apparatus includes a well tree having a production bore and a flow metering valve coupled to the well tree and communicating with the production bore. The flow metering valve Includes a valve member having a first passage defined therein with a metering flow profile and a second passage defined therein with an unrestricted flow profile. The second passage having a diameter substantially equal to a diameter of the production bore.

Abstract: A valve includes a gate and an actuator. The gate has a gate opening with a first seal fixed to the gate and positioned along a periphery of the gate opening. The gate also has a blocking portion with a second seal fixed to the gate and positioned along a periphery of the blocking portion. The actuator is configured to move the gate between an open position and a closed position, wherein the gate opening is aligned to a chamber opening in a chamber wall and the first seal engages a sealing surface of the chamber wall in the open position and wherein the blocking portion is aligned to the opening in the chamber wall and the second seal engages the sealing surface of the chamber wall in the closed position. The valve is capable of operating in harsh environments.

Abstract: A pig receiver and method retrieve pigs in pipeline pigging operations. In one embodiment, a pig receiver includes a pig receiver unit. The pig receiver also includes a pig gate valve assembly disposed on the pig receiving unit. The pig gate valve assembly includes a gate valve. The pig gate valve assembly also includes a first actuator and a second actuator. The pig gate valve assembly further includes a cylinder guide. In addition, the pig gate valve assembly includes a tie bar. Actuation of the tie bar actuates the gate valve. An end of the tie bar is attached to the first actuator, and an opposing end of the tie bar is attached to the second actuator.

Abstract: Embodiments of a gate valve equalization system comprise: a gate valve; a gate; a preloading valve arrangement; a floating coupler assembly; a relief valve arrangement; and a means for control. The preloading valve arrangement permits fluid to enter the valve body from the upstream side of the gate. The means for control serves as a control interface allowing engagement of the floating coupler assembly and opening/closing of the gate valve. Engagement of the floating coupler, engages the assembly relief valve arrangement and allows redistribution of fluid pressure and circulation of fluid from one side of the gate to opposing side of the gate within the gate valve.