Abstract: A cryogenic gate valve having a body with a full passage formed therein. A gate has opposed faces at an acute angle with a recess formed in one face of the gate. The recess receives a sealing means that is comprised of a sealing ring having a base flange and an annular flange, and a rigid securing disk having a peripheral flange. The annular flange on the sealing ring has multiple concentric sealing ribs. The interface surface between the disk and the sealing ring extends at a taper angle to the face of the gate.

Abstract: A peripheral sealing gasket is disclosed for use in mounting a discharge gate to the adapter frame of a railroad hopper car. The gasket has a peripheral base formed of a relatively rigid sealing material, which base is formed and adapted to be positioned between and in substantial surface contact with a discharge gate mounting flange and the hopper car adapter frame. The base has at least one sealing element on each side thereof, which sealing elements extend outwardly beyond the base and are formed of a sealing material substantially less rigid than the base. There is a recess for each sealing element whereby each sealing element will distort into its recess during use so that the base is in substantial surface contact with the mounting flange and adapter frame throughout its peripheral extent.

Abstract: An improved seal ring for sealing across the annular space between the exterior of a seat ring and the inner surface of a counterbore recess surrounding the entry of either the inlet or outlet into the valve chamber within the valve body, the seal ring including a pair of radially extending flanges connected by a tubular connector extending between the radial midportions of the flanges and the leading flange having inner and outer sealing surfaces which provide a high interference fit seal between the recess inner surface and the seat ring outer surface and the trailing flange having inner and outer sealing surfaces which provide a low interference fit seal between the recess inner surface and the seat ring outer surface. A spacer ring is provided to seat against the shoulder of the counterbore recess and retain the sealing flanges.

Abstract: The collar of a one piece liner for a gate of a gate valve includes inwardly sloping entry surfaces for urging packing compressed by a packing gland against the gate to effect a seal about the gate without an increase of packing gland pressure. Bead seals disposed upon the inwardly sloping surfaces cooperate with the packing to prevent leakage intermediate the sloping surfaces and the packing. Further bead seals extending about the interior of the throat of the chest bear against the gate to serve a sealing function and to discourage migration of the packing into the throat.

Abstract: A gate valve includes:(1) an inlet;(2) an outlet;(3) wall means for defining a flow path between the inlet and the outlet;(4) a bonnet wall which defines a bonnet space; and(5) at least one valve seat.A gate is selectively movable between a first gate position, in which the gate is retracted away from the valve seat and the inlet communicates with the outlet, and a second gate position, in which the gate contacts the valve seat, thereby preventing flow from the inlet to the outlet, the gate having a seal surface which contacts the valve seat when the gate is in the second gate position. At least one valve seat protector is selectively movable between a first seat protector position, in which the valve seat protector covers the valve seat, and a second seat protector position, in which the valve seat protector is retracted away from the valve seat. The gate is movable between the first and second gate positions and the seat protector is movable between the first and second seat protector positions.

Abstract: A knife gate valve for regulating particular material flow in a pneumatic or vacuum covering system. An actuated, reciprocative gate is mounted within the valve housing on guide bars which define the path of gate movement between open and closed positions. The guide bars seal the side edges of the gate and the adjacent portion of the lower gate surface. A seal plate is loaded by a pair of o-rings to seal against the top gate surface. Transverse seals are accessible for cleaning or replacement through releasable side seal assemblies. Fluid ports allow the transverse seals to be lubricated in place or air purged. The guide bars are cleaned by the gate during closure with the opposed gate surfaces being cleaned by the seal plate and an underlying wiper bar during gate movement. The cleaning actions cooperate with dynamic loading of the various seals to assure a proper seal about the gate upon closure.

Abstract: An actuator for opening and closing the gate of a surface safety valve includes a primary piston and an auxiliary piston. The primary drive piston is directly connected to the valve stem, while the auxiliary piston is slideably connected thereto. Extension movement of the auxiliary piston is stopped by a divider plate after initial breakaway forces are overcome. The thrusting force developed by the auxiliary piston during a valve opening operation is transmitted to the valve stem and the primary piston by a shuttle sleeve. The shuttle sleeve is radially spaced about the valve stem, thereby defining a bridge annulus which maintains fluid communication between the primary pressure chamber and the auxiliary pressure chamber at all times. The thrusting force produced by the auxiliary piston is combined with the thrusting force produced by the primary piston to break the static gate seal and overcome the gate drag during a first stage of operation.

Abstract: A valve slide includes a slide housing and defines a slide passage opening. The slide passage opening is closable by a closing member which is slidable in the plane of the slide. A sealing surface surrounds the slide passage opening. In the closed position of the closing member, a circumferentially closed sealing member rests against the sealing surface. Imaginary straight generatrices of the sealing surface extend at a right angle to the plane in which the axis of the slide and the sliding direction of the closing member are located. In the direction of the generatrices of the sealing surfaces, the sealing surface has an upper portion, a middle portion and a lower portion. The upper portion and the lower portion each include an obtuse angle with the middle portion. The planes of the upper portion and the lower extend approximately perpendicularly to the sliding direction of the closing member.

Abstract: A valve seat structure and assembly for a gate, ball, globe or plug type valve adapted to enhance the high-pressure seat sealing capabilities thereof, comprised in alternate embodiments of either a single or a cooperative set of rings having either an interior or exterior geometrically configured circumferentially recessive undercut channel to provide an overhang flex-lip structure against which the closed valve plug compressively seats in flex communicative seal on one side thereof and pressurized line fluid exerts a uniformly distributed circumferential counter flexure deflective force on the other side thereof, wherein the preferred embodiment overhang flex-lip structure is provided with a radially spaced plurality of flex-limit stop posts within the undercut channel thereof whereby valve plug compressive deflection of the flex-lip is restricted to less than that amount which would exceed the permanent distortion flex limit of a particular material from which the valve seat rings are constructed.

Abstract: An improved gate valve is described. The valve utilizes a flat gate having a beveled edge which slices across a central passage in the valve housing when the valve closes. A manifold is disposed in the passage to direct a purge stream of fluid across the beveled edge as the gate closes. The valve housing consists of upstream and downstream housings which are intended to be bolted together. The adjacent portions of the housings form a first slot in which the gate is slidably received and a second slot downstream of the second slot is formed in the downstream housing. In one embodiment a seat is slidably disposed in the slot which extends laterally across the passage parallel to the gate. In another embodiment the slot extends axially along the passage and the seat is cylindrical slidably retained therein. In the cylindrical seat embodiment the seat is reversible.

Abstract: A packingless gate valve comprises a housing having two opposed resilient sleeve units that compressibly engage end to end in the valve open condition and engage opposite sides of the gate in the valve closed condition. Each sleeve unit is a resilient annular body formed at one end with an axially projecting seal lip near the inner periphery and has a stiffener ring enclosed adjacent the outer periphery at the one end. An integral gasket forming flange is formed on the other end of the sleeve body.

Abstract: A gate valve body member 10 and plastic liner 12 define a flow passage 24 therethrough which communicates with a pair of pipes 34 bolted to the gate body. The liner has a bottom seating surface engageable by the gate 22 and extending from a central point outward to the sides of the flow passage. A top opening recess 54 in the liner 12 receives the gate in a slidable sealing fit. The recess and gate are wider than the flow passage and defining walls of the gate receiving recess terminate at the bottom intermediate the center and sides of the seating surface to provide side sealing and pressure backing support in both directions of flow for a lower portion of the gate and particularly a support below the horizontal center line of the flow passage. The seating surface includes a central arcuate surface portion and straight surface portions joined therewith and extending outwardly to the sides, the bottom edge of the gate being configured to fit the arcuate and straight surface portions.

Abstract: A through conduit gate valve apparatus having a valve seat assembly that is field maintainable and which prevents the occurrence of pressure lock is disclosed. Each valve seat assembly includes a retainer ring fixed in the valve body and a pressure responsive seat ring that seals with the gate member. The seat ring is responsive to fluid pressure in the valve flow passageways for maintaining and enhancing the face seal with the gate and to fluid pressure in the valve chamber for automatically venting the valve chamber to prevent occurrence of a pressure lock condition.

Abstract: A packingless gate valve is disclosed which includes a housing having opposed similar housing halves with pipe nipples extending therefrom and with resilient sleeve units installed on respective lock rings mounted in recessed portions of the housing halves. The sleeves act to compressibly engage each other in the valve open condition and engage opposite sides of the gate in the valve closed condition. Each sleeve unit has a radially outwardly extending flange on the inner and outer axial ends with these flanges being located in indented regions between each lock ring and the respective housing half. An encircling thin stiffening ring of harder material is bonded to the axially outer surface of the flange on the inner end of each sleeve, each stiffening ring being shaped with a right angle bend so as to provide both axially and radially facing surfaces for each sleeve body. Each stiffening ring is engaged with the respective lock ring along the entire length of the stiffening ring.

Abstract: A valve arrangement has an outflow seat section defined by at least a tubular side wall. The outflow seat section has a free end with an engaging part extending along the entire periphery of the side wall. The engaging part is adapted for close engagement with an engaging surface of a movable obturating plate. The engaging surface is substantially parallel to a plane of the engaging part and remains substantially parallel to this plane during movement of the obturating plate toward and from the free end of the outflow seat section. During operation of the valve arrangement the engaging surface of the obturating plate simultaneously engages the entire plane of the engaging part of the outflow seat section causing closing of the valve arrangement.

Abstract: A gate valve improvement including a seat-to-body seal means for reliable bi-directional sealing, a port to bypass at least one of the seat-to-body seals, and means to plug the bypass port when the operation of this seal is desired.

Abstract: A valve slide has a housing with a sealing surface which has portions located one behind the other seen in direction of the axis of a slide passage opening. The portions located one behind the other are connected to outwardly extending plane sealing surface portions through continuously extending curved portions. The imaginary generatrices of the sealing surface portions forming a sealing surface extend parallel to the axis of the slide passage openings. The sealing surface is finished. The closing member has a contact surface corresponding to the shape of the sealing member. The slide can be used in vacuum systems. The closing member is formed of one piece and can be subjected to high accelerating forces, so that the slide can be used for quick-closing valves and emergency valves.

Abstract: A throttling gasket insert (34) for attaching a knife gate valve (10) into a pipe string is constructed of a single piece of resilient gasket material having a washer-shaped flange portion (36), to be clamped between a facing surface (52) of a knifegate-valve face plate (26) and a pipe flange (60), and a tubular portion (42), extending through a knife-gate valve flow passage (22) to a knife-gate blade (12) thereof, having a V-shaped passage therethrough.

Abstract: A kelly cock valve for a drill rig uses a sliding gate to open and close the flow passage through the drill string. The valve has a body with a longitudinal passage through it. The gate is mounted in the body perpendicular to the flow passage. Pushrods extend from each end of the gate out through bonnets mounted to the body of the valve. The fluid cylinders are mounted on each side of the gate. Each fluid cylinder has a piston with a piston rod extending in opposite directions. The piston rods are connected to a beam that also connects to the pushrod. Hydraulic passages supply fluid to the cylinders to stroke the piston and thus move the gate valve between open and closed positions.

Abstract: Disclosed is a gate valve for controlling flow, providing a dual seal, including a valve body having a discharge orifice. A gate assembly, located upstream of the discharge orifice, is movable between open and closed positions remote from and blocking the discharge orifice, respectively. The gate assembly includes upper and lower spaced flexible sealing disks which are attached to a relatively rigid upstream backup plate. Radially inner and outer valve seats are secured to the valve body adjacent the discharge orifice. When blocking flow through the valve body, each gate is wedged in sealing engagement with a respective valve seat and a chamber is formed between the two seals to receive seepage past the upstream seal. The chamber may be either evacuated or pressurized to prevent flow of controlled material past the lower or downstream seal.

Abstract: A raised hardface overlay valve seat, fused around the periphery of the port of a valve, having an inverted frustoconical body cavity and an inverted frustoconical plug inserted into said cavity in sealing engagement therewith. A major advantage of the raised hardface overlay seat is that it has a taper conforming to the taper of the plug and as a consequence, reduces the area in contact with the plug and effectively intensifies the sealing stress that can be generated between the plug and the seats by a downward force. The plug may be used with lapping compound to lap the seats, both prior to service and in the field. Sufficient space is allowed in the cavity for a substantial relap life.

Abstract: The slide or gate valve (10) suitable in particular as pressure valve comprises a valve housing (12) in which a relatively wide and preferably double-walled closure body (14) is displaceable. The sealing of the closure body (14) within the valve housing (12) in the closed state is via a pressure-activatable seal (66). Downstream of the closure body (14) a tubular member (30) of increased diameter is disposed which serves as expansion member. The features of the very wide closure body, the pressure-activatable seal and the expansion member (30) make it possible to actuate the valve when pressure is in the conduits through which a gaseous or liquid medium charged with a high proportion of solid is conveyed.

Abstract: An improved gate valve for effective sealing regardless of the pressure of the fluid of the conduit to which the valve is attached. The gate valve comprises a body (20) having opposing upstream and downstream sides (46, 44). Each side has a conduit-joining surface (72, 73) formed thereon. The body is configured for connection between two axially aligned conduits (24, 25) with each conduit-joining surface abutted against the end of an associated conduit. A resilient liner (27) is attached to the body between the valve gate (32) and the body (20). The liner also covers the portion of the body that defines the port. The liner includes a sealing surface (60) formed thereon. The sealing surface is configured for sealing contact with the portion of the edge surface of the gate that resides within the body when the gate is in the closed position. The gate valve also includes at least one seal ring (62) positioned against the body at the periphery of the port on one side of the gate.

Abstract: A gate valve having a metal-to-metal seal between the gate (26) and the seat carrier (20) and a metal-to-metal seal between the seat carrier (20) and the valve body (10) with the seat carrier and valve body having complementary spaced frustoconical surfaces (18,22).

Abstract: A gate valve formed with spaced parallel housing plates having axially aligned apertures which constitute a housing therebetween. Elastomeric sleeves line the apertures of the housing plates to provide an annular space between the sleeves. An elongated gate plate, having an apertured section and an imperforate section, is positioned in sliding contact with the sleeves. Actuator means reciprocate the gate plate between an open and closed position.

Abstract: The improved pre-loaded valve follower sealing apparatus comprises a follower ring and flange insert assembly. The assembly includes a pair of hollow cylinders compressively containing a follower preload and sealing element. That follower preload and sealing element is substantially annular in shape, but has an interior fluid contacting surface which is concave in transverse cross-section when not under compression, but which is rendered substantially smoothly cylindrical when placed under compression.

Abstract: In a sealing mechanism for a damper plate for a duct, seal members are made in the form of multi-convoluted sheet metal bellows, which engage each side of the damper plate around the periphery of the duct. When the duct is moved from an open position to a closed position, it slides between the seal elements forcing them apart. When the plate is slid from a closed position to an open position, the spring bias in the bellows members will cause them to expand to engage each other.

Abstract: The gate valve includes a body having a valve member or gate chamber, passages communicating through the body into the chamber, a recess in the body surrounding the opening of each passage into the chamber, a bushing positioned in each of the recesses, a gate positioned within the chamber, means for moving the gate within the chamber between positions communicating flow between the passages and closing flow between the passages, inner and outer unidirectional seals positioned between the surface of each of the recesses facing the gate and the opposing surface of the bushing in the recess, each of the seals include a U-shaped lip sealing element and a U-shaped spring positioned within the lip sealing element and urging the legs of the element apart into sealing engagement between the bushing and the body, the inner seal, which is positioned closest to the passage has the open end of its sealing element facing the passage and the outer seal, which is farther from the passage than the inner seal, has the open en

Abstract: A valve such as penstock with a gate (13) which slides across an opening in a frame (10, 11, 12). On at least one side of the gate (13) is a two-part sealing strip consisting of resilient layer (22) and a superimposed bearing portion (23). Attached to or integral with bearing portion (23) is a thickened part (24) which limits the maximum compression of the resilient layer (22) when the valve is closed.

Abstract: The slide valve of the present invention is adapted for use in horizontal piping runs. It comprises a valve body, an orifice plate, a sliding plate and guide means for the sliding plate. The orifice plate is located in the valve body and inclined at an angle, .alpha., selected to achieve a predetermined seating force when the sliding plate, also inclined, is in the valve body in the closed position and bearing on the orifice plate. The guide means are provided for guiding the slide plate when it is moved in and out of the valve body under conditions of use.

Abstract: A damper mechanism of the slide gate type includes two curved seal segments positioned in back-to-back abutting relation to function as the primary flue seal. A seal door when closed extends between the upper ends of the seal segments and applies compression to the spaced appart ends to form, in combination with the seal segments, a closed chamber which functions as a secondary seal. Means are provided for applying a thrust force to the upper end of one of the seal segments to move that seal segment into abutting relation with the other seal segment when the slide gate is withdrawn. In a preferred embodiment, the thrust force is applied by the seal door during its closing. In another preferred embodiment, the closed chamber formed by the seal door and seal segments is enlarged and compressed air is pumped into the chamber to improve its functioning as a secondary seal.

Abstract: A knife gate valve comprises a body member to which two aligned conduits are attached. The body member has a U-shaped internal recess of predetermined length formed within it. A removable sealing member fits within the recess and extends along its entire length. The sealing member includes a bearing portion and a resilient backing portion that are positioned face-to-face to each other. The bearing portion comprises a flexible plastic-type material having a self-lubricating, semi-hard surface that contacts the blade portion of the gate as it slides along the length of the recess to close the valve. The resilient backing member comprises an elastomer strip that contacts the bearing portion surface that is opposite to the blade portion contacting surface. The resilient backing portion yields to the pressure exerted by the gate as it closes, thereby to provide a tight seal for the valve.

Abstract: Gate valve means connected in a waste pipe system have a hollow housing with an inlet and an outlet connected to the waste pipe system. A blade is disposed in the housing at a substantially right angle to the waste pipe system and is selectively movable between a closed position blocking the inlet from the outlet, and an open position allowing waste flow between the inlet and outlet. The blade moves between the open and closed positions and a pair of seals are disposed in the housing in an abutting relationship aligned to receive the blade therebetween when in the closed position and to seal waste flow between the inlet and outlet from the interior of the housing when the blade is in the open position. Each of the pair of seals has a unique design enabling it to mechanically rotate with the blade, thereby limiting wearing forces thereon.

Abstract: A packingless gate valve is disclosed which includes a housing having opposed similar housing halves with resilient sleeve units which compressibly engage each other in the valve open condition and engage opposite sides of the gate in the valve closed condition. Each sleeve unit has a flange on the inner and outer axial ends, with the flanges extending radially outwardly from the sleeve body. An encircling thin stiffening ring of harder material is bonded to the axially outer surface of the flange on the inner end of each sleeve, each stiffening ring being shaped with a right angle bend so as to provide both axially and radially facing surfaces for each sleeve body. The particular configuration and position of the stiffener rings has been found to function advantageously in preventing the pliable sleeve material from following the gate as it penetrates between the opposed sleeve units.

Abstract: A gate valve for pulp stock slurries and the like has a smooth flow passage for two way flow and has no grooves or cavities where pulp stock fibres or other particles collect. The valve comprises a rigid valve body having a flow passage with smooth curved walls therethrough, the body having a gate blade slot in the approximate center of the flow passage, a flexible resilient seat flush with the smooth curved walls, the seat being in the form of a strip extending through one end of the gate blade slot, around the flow passage and through the other end of the gate blade slot, the strip held in place by a body port insert ring attached and sealed to the valve body, and a gate blade with a semi-circular end, the gate blade adapted to fit in the gate blade slot to seal against the resilient seat.

Abstract: A hot-blast valve for use between a regenerative heating stove on and a blast furnace downstream therefrom in the direction of flow from the stove to the furnace according to the invention has a valve housing made of metal plate and having a lateral gate pocket. Annular upstream and downstream seats define a flow passage and the upstream seat is made of metal and the downstream seat of solid refractory material. A gate is displaceable between the seats between a closed position engaging same and blocking the passage and an open position clear of same in the pocket with the passage open. A coolant is circulated through the upstream seat only.

Abstract: The invention relates to a device for shutting off a pipe using generally U-shaped spring steel strips as sealing elements, each such element comprising a pair of arms which converge toward one another form an arcuate web at an acute angle. The deformation of the two flat arms of these sealing elements is limited by two flat, rigid rolling surfaces which are tangential to the web. Such a construction is distinguished by satisfactory functioning and a long working life.

Abstract: An apparatus for sealing a flow control apparatus, such as a guillotine damper, is disclosed. The apparatus of the invention is particularly intended for dampers or other flow control devices utilizing pressurized sealing air to effect complete sealing. The closure member is of the type that moves completely out of the main fluid passageway when opened. Each of the two lateral seals, which cooperate with lateral edges of the closure member, includes an extended portion with a curved segment which takes the form of a cylindrical arc to stiffen each lateral seal against movement normal to the plane of the seal. This, in turn, allows considerable reduction in the clearances and gaps in the corners between the lateral seals and an entry seal to reduce the flow volume of the sealing air, to reduce the overall power requirements, and to reduce energy consumption.

Abstract: This invention relates to an improved gate valve having floating seal elements which are back-relieving and reversible for long-term permanent sealing under varied pressure conditions. The sealing elements are mounted in unrestrained relation in juxtaposed recesses in the fluid passage facing the movable gate with annular gaskets facing both the gate and the recesses for improved self-aligning sealing engagement therewith. The sealing elements and their annular gaskets may be reversed, interchanged, or readily replaced as desired, the valve structure being especially useful for inherently fail-safe slab type gate valves.

Abstract: A gate valve 10 of slab gate variety with "floating" seats having means for protecting the seat ring seals and seat pockets in severe operating conditions. Each seat ring (40,41) is provided in its rear face (43,44) with an annular groove (49) coaxial with the ring axis and of a diameter to be located closely adjacent the flow passage (16,17) through the valve and accommodating an O-ring seal (49,50) therein. A second annular groove (51) is formed in the outer cylindrical surface (40a, 41a) of the ring near the front face (43,44) of the ring and accommodates an O-ring seal therein. The two O-ring seals (49,52) and (50,51) by their location establish a "trapped" volume chamber (55) behind the seat ring and seat pocket (32,33) which protects and isolates the seat pocket from corrosive ladings and solids deposition.

Abstract: A slide gate valve having a flangeless housing clamped between the ends of two pipelines which housing has an inner chamber, enlarged between the ends of the pipelines, for accommodating a stationary valve plate. An associated displaceable valve plate is provided with an annular insert having approximately the same inside diameter as the adjacent pipeline on the discharge side in the housing, against which insert the stationary valve plate is supported as a seal in a small annular area opposite the sealing surface between the insert and the pipeline. The remaining area of the stationary valve plate is free of support from both the insert and the housing.

Abstract: A gate valve having a body with a valve chamber therein, an inlet passage through the body into the valve chamber, an outlet passage through the body into the valve chamber, a gate positioned within the chamber and having an opening therethrough, a body sealing surface surrounding the openings of each of the inlet and outlet passages within the passages within the chamber, a seat ring positioned between the gate and each of the body sealing surfaces, means for urging the seat rings against their body sealing surfaces, resilient seals between each seat ring and its body sealing surface near the inner and outer diameter of each ring, means for sealing between the gate and the seal rings, and means for moving said gate in said chamber to close and open flow through said valve.

Abstract: A gate valve, seat, and face seal therefor, the valve including a valve body defining a longitudinal flowway and a valve element mounted in the valve body and movable transverse to the flowway between open and closed positions. The valve seat mounted in the valve body includes a seat body having an axially facing annular contact face for opposition to the valve element and an annular groove extending axially thereinto, the annular groove in turn having inner and outer side walls. The face seal comprises an annular elastomeric seal body having a base portion disposed in the annular groove and a sealing portion which, in a relaxed condition, projects axially outwardly from the annular groove. The seal body further has an annular auxiliary sealing formation extending about its outer diameter and sealing engaging the outer side wall of the annular groove.

Abstract: A valve assembly including an annular ring having an inwardly directed projection and a seal having a groove into which the projection is fitted. The seal has a sealing surface which engages a valve member. The seal has two ribs which project from the sealing surface and a protrusion extending into the groove, the ribs and the protrusion engaging respectively the valve member and the annular ring for providing a bubble-tight seal.

Abstract: A fluid valve system (10) is provided to control fluid flow passing from a conduit passage (12). The valve system (10) includes a movable closure (20) which is reversibly displaceable in a transverse direction (22) passing in a direction substantially normal to the fluid flow passing in a longitudinal direction (14). The movable closure (20) is insertable within the conduit passage (12) in order to block or cut off the fluid flow passing through aligned conduits (16 and 18). The valve system (10) includes a pair of resilient sealing mechanisms (34) which provide for substantially planar second sealing base members (46) for resiliently contacting opposing surfaces (48 and 50) of movable closure (20). Additionally, there is provided a biasing mechanism (56) for resiliently biasing the second sealing base members (46) into contiguous contact with surfaces (48 and 50) of movable closure (20) over an extended area.

Abstract: A valve seat in a knife gate valve is positively retained between a liner and a retaining ring.

Abstract: A floodgate structure is disclosed for closing of an hydraulic flow channel at selected times, as during flooding conditions. A gate panel is normally loosely and slideably received in a recess below grade level. To render the gate operational, it is lifted into a channel-blocking position. Pneumatically inflatable peripheral sealing elements extend from the water side of the panel into sealing contact with a fixed support structure. The opposite side of the panel supports a flexible but noninflatable sealing skirt element, which is pressed into sealing contact with the supporting structure by expansion of the inflatable elements. When thus positioned, the sealing skirt becomes hydrostatically loaded by the pressure of the water and functions as an effective seal in the event of subsequent failure of the pneumatically expandable elements.

Abstract: There are disclosed alternative embodiments of a downstream sealing gate valve of the type in which a pair of seats are carried within the body of the valve for sealing between the body and either side of the gate.

Abstract: A stem-operated fire-resistant gate valve including an improved metal-to-metal stem backseat fusible ring assemblies for facilitating automatic stem backseating at pre-selected temperatures, spring enhancement of the backseating procedure, and an improved metal-to-metal gate seat.

Abstract: A seal device for a gate valve is disclosed, in which annular members facing the front and rear surfaces of a gate valve member having a through hole are coupled to a valve cage by inner and outer bellows, each of the annular members has an annular recess formed on the side facing the gate valve member and closed by an annular mirror surface finished thin plate secured by welding to an opening thereof, the individual bellows are elongated by fluid under pressure supplied into annular spaces defined by the inner and outer bellows, and the annular mirror surface finished thin plates are strongly urged against the gate valve member by the pressure of the fluid forced from the annular spaces into the annular recesses. Edge portions of the annular mirror surface finished thin plates are to be very firmly mounted to the annular members, and the mechanical strength of the thin plates is to be increased.