Abstract: A vacuum pipe for a part which is mounted so as to be movable and projects from outside a vacuum chamber into a vacuum in the vacuum chamber, comprises an opening in a wall of the vacuum chamber limiting the vacuum, with an inner side facing the vacuum and an outer side at which is provided an annular sealing surface surrounding the opening, an annular sealing surface at the part projecting through the opening into the vacuum from outside the vacuum, a sealing arrangement which is provided between the annular sealing surfaces of the wall and of the part and which comprises at least one sealing ring of elastic material, and a guide device which guides the part relative to the wall and by which at least a minimum axial pressing force is maintained on the at least one sealing ring in every position of the part, resulting in a deformation of the at least one sealing ring such that tightness is ensured, wherein the deformation of the sealing ring changes at least in areas of the sealing ring when the part moves re

Abstract: A returning spring 7 of the electronic control throttle and a default spring 8 for securing an initial opening degree (default opening degree) of the throttle valve 3 have diameters different from each other, and both of the springs 7, 8 are held around a shaft of the throttle valve shaft 3 and arranged between a gear 43 attached to the throttle valve shaft 3 and a wall portion of the throttle body 100. A shaft supporting gap of the throttle valve shaft 3 is filled with an air leak preventing material, and a minimum opening degree of the throttle valve is set to a value larger than an amount of overshoot of the throttle valve occurring when opening degree of the throttle valve is changed from a maximum opening degree of the throttle valve to the minimum opening degree.

Abstract: A structure for fixing a washer for preventing the deviation of the structure engaged with the inner side of a injection molded pipe holder. A control valve for a gas cylinder comprises a pipe holder having a passage on the outer peripheral surface thereof and injection molded such that a space for engaging a structure and a liner recess having a periphery corresponding to the outer diameter of the structure are formed at the lower portion thereof, and a washer for preventing the deviation and the flowing of the structure with which the pipe is engaged. A plurality of embossed bosses are pressed to the lower portion of the washer by pressing the bosses along the periphery of the extending surface of the engaging inlet of the structure of the pipe holder from a liner recess formed at the lower portion of the pipe holder by using an exterior pressing device to fixing the washer to the pipe holder.

Abstract: A packer joint is provided for mounting on a vessel or pipeline entry valve which includes a stinger guide and seal. Clamping collet are mounted within the packer to retain the stinger in the desired position. Different metals within the guide body from those of the stinger rod prevent gaulding and damage. A lock-up the rod may be released via a bore hole providing tapping access to the collets.

Abstract: Live loaded valve stem packing wherein grafoil packing is molded into a metal cap that prevents extrusion of the packing, and has live loading built into the metal cap. This metal cap can be conventional flat spring materials (17-7PH S.S. or 302 S.S.) or a Shape Memory Alloy (commonly known as SMA materials, e.g. Ni—Ti (Nickel-Titanium alloy) or Fe—Si—Mn (Iron-Silicon-Manganese alloy). The cap is designed with a singular hump, entirely along its top surface. On this hump there are two slots through the hump, 180 degrees apart, for ease of removing the packing. Upon assembly of the packing box, the hump is elastically flattened out due to axial loading through the fasteners. As the packing consolidates during service (optionally if the cap is SMA, during temperature increases) the hump deflects to maintain a relatively constant or enhanced axial load on the packing to enhance sealing, even during a fire.

Abstract: A rotary valve is provided with an elliptical valve disc that seats against a seal element operatively mounted in an elliptically shaped depression formed in the rigid annular portion of a seal cartridge structure carried by the valve body. Due to the elliptical shapes of the disc and corresponding seating structure, and a conical configuration of the disc periphery, sealing of the valve disc, the integrity of the seal, and the ability of the seal to completely stop the flow of fluid through the valve body are desirably improved. The centering of valve disc relative to the seal cartridge is facilitated by a specially designed disc mounting structure that eliminates any necessity of adjusting the disc along its rotational axis, and a one-piece actuator bracket is removably mounted to the valve body to substantially simplify and reduce the expense of operatively associating an actuator with the valve.

Abstract: A shield for a gas management pintle valve, such as an exhaust gas recirculation valve for an internal combustion engine, for mitigating leakage of gas and moisture along the valve pintle into the actuator, to prevent corrosion and failure of the actuator. The shield is a tubular member having an equatorial radial flange and is slidably mounted on the pintle in an annular chamber between the valve body and the actuator. The inner diameter of the tube is selected to be as close-fitting to the pintle as possible while still being slidable thereupon to be adapted to either of two operating positions. During engine shutdowns, the shield is drawn by gravity toward the valve body to form a first seal with the flange against the pintle bearing or a bearing splash shield, preventing or minimizing the escape of moist, hot gases under low pressure from the valve along the pintle.

Abstract: An improved modular, radially-compliant, redundantly-sealing journal-type bearing assembly comprising two bearing elements retained in a housing and positively loaded in opposing directions by a compression spring disposed therebetween. A shaft to be supported and sealed against leakage by the bearing, such as a valve pintle shaft, is disposed in an axial bore in each of the bearing elements, which bores are fitted as closely to the diameter of the shaft as is possible without causing the shaft to bind in the bores. Each of the radial bearing faces opposite the spring forms a seal with a corresponding internal surface of the housing, defining thereby a redundant sealing system. The bearings are radially compliant within the housing by a predetermined small distance to allow the shaft to be operatively self-centered, such as by an attached valve head mating into a valve seat.

Abstract: A ball valve having a ball-style closure member that is trunnion mounted in a valve body includes a stem seal and two backup rings that are axially disposed on the stem adjacent the seal. One of the backup rings includes a tapered face that seats against a tapered shoulder of the stem so that under pressure the backup ring is radially forced against a passageway wall in which the stem is disposed to prevent extrusion and to function as a load bearing surface. Alternatively, the backup ring can be compressed against the stem wall. The closure member may also include a plurality of low friction bearings disposed on the stem on opposite sides of the seal and backup ring assemblies, and may also include a trunnion bearing disposed on a lower trunnion of the closure member. The tapered backup ring is preferably made of a harder material, such as PEEK, compared to the material of the other backup ring which may be, for example, TEFLON™. The bearings may also be TEFLON™ or PEEK, for example.

Abstract: A floating stuffing box is disclosed which prevents leakage caused by oscillation of the valve stem compressing packing material by instead allowing for movement of the ball within the socket of the base wall as lateral movement of the base.

Abstract: A worker inserts a correcting pin into bearing members. Then, a cylindrical portion and retaining portions are molded together into an integrated resin unit. After finishing the molding operation, the worker extracts the correcting pin from the bearing members and subsequently inserts a throttle shaft into the bearing members. Accordingly, an axial center of the bearing member accurately agrees with an axial center of the bearing member. Then, the worker fixes a throttle valve to the throttle shaft.

Abstract: A valve stem has a thickness of hardfaced material on its outer diameter in the area contacting the stem packing where the seal is formed which prevents corrosion, erosion and/or scratching of the valve stem, thereby preventing formation of leak paths. A valve packing comprises a vertically stacked array comprising alternating metal pressure rings and graphite seals.

Abstract: A decelerator device obtains constant and maximal decelerating power includes by controlling the gas pressure upstream of the valve by balancing the efforts at the pressure-relief valve. The decelerator device (1) includes a balancing device (20) incorporated in the gate (2) body (4) and has a leakage conduit (21) controlled by a calibrated check valve (22). When the valve (7) is closed and, based on a counter-pressure threshold predetermined by the calibration of the compression spring (27) provided at the check valve (22) rear, the latter is lifted from its seat (25) and communicates the channel (5) upstream of the valve (7) with the leakage duct (21) generating an exhaust gas leakage. Beyond the threshold, the calibrated check valve (22) remains open, thereby ensuring constant and maximal counter-pressure whatever the engine speed. The invention is applicable to combustion engine vehicles and in particular industrial vehicles.

Abstract: A valve stem has a thickness of hardfaced material on its outer diameter in the area contacting the stem packing where the seal is formed which prevents corrosion, erosion and/or scratching of the valve stem, thereby preventing formation of leak paths. A valve packing comprises a vertically stacked array comprising alternating metal pressure rings and graphite seals.

Abstract: A valve stem has a thickness of hardfaced material on its outer diameter in the area contacting the stem packing where the seal is formed which prevents corrosion, erosion and/or scratching of the valve stem, thereby preventing formation of leak paths. A valve packing comprises a vertically stacked array comprising alternating metal pressure rings and graphite seals.

Abstract: The present invention provides an interchangeable modular valve-actuator combination whereby the valve stem on the valve and the actuators are configured to be interchangeably engageable. The components of the valve-actuator are sized accordingly so that when engaged, the valve-actuator combination fits within the confines of an emergency hood located under the dome of a transportable tanker.

Abstract: A valve with fire-resistant seal for use in industrial piping applications. The valve includes a valve body with a valve element therein. The valve is illustrated as a ball valve, but other valve configurations could also be used. A valve stem engages the valve element so that it can be rotated between open and closed positions. A conventional primary seal is used on the valve stem for normal conditions. The valve body defines a body bearing surface, and the valve stem defines a facing stem bearing surface. A thrust bearing is disposed between the body and stem bearing surfaces, and a fire-resistant seal is positioned radially inwardly from the thrust bearing. Initially, the fire-resistant seal is not engaged with at least one of the body or stem bearing surfaces, and the fire-resistant seal has a thickness less than an initial thickness of the thrust bearing.

Abstract: A tap has a hollow body (6) having an interior threaded portion (18) and (9). A manually turnable spindle (7) having an exterior threaded portion (19) is threadably engaged with the interior treaded portion (18) to advance and retract to spindle (7) relative to the tap body (6) to respectively close and open the tap. A seal (28) seals the spindle (7) relative to the hollow body (6). A locking mechanism including mutual abutent portions (27, 13) on the body (16) and spindle (7) to limit the retraction of the spindle (7). The relative lengths of the threaded portions (18, 19) and the relative locations of the mutual abutment portions (27, 13) are selected so that continued turning of the spindle (7) in the retraction direction disengages the threaded engagement prior to abutment of the mutual abutment portions (27, 13).

Abstract: An improved bottom entry cryogenic valve, with single piece cast body, that provides for easy and efficient removal of the valve stem and valve seat components without removing the valve body from the fluid circuit. The valve body forms the housing and has a top end, a main body section and a bottom entry end. The main body section has fluid entry and fluid exit openings. A bonnet nut is attached to the valve body top end. A body ring is attached at the bottom entry end. A valve stem extends axially through the bonnet nut, with a top portion exposed with a hand wheel attached thereon. The valve stern has a mid portion, a flange portion and a threaded bottom end located in the main body section of the valve body. The valve stem mid portion supports a valve seal member and a seal nut/bearing. The valve seal member is to prevent fluid from flowing through the valve body when the valve is in a closed position. The seal nut/bearing acts to restrict fluid from entering the top end portion of the valve body.

Abstract: A post valve for use with a source of high pressure gas is disclosed. The post valve includes a body having an inlet aperture extending therethrough. The body further includes an outlet aperture in fluid communication with the inlet aperture. A stem having external threads is rotatably inserted into the body aperture and engages mating threads within the body. A fluid seal disposed about the stem prevents fluid flow past the stem. A threaded bonnet is disposed over the stem and mates with another threaded portion within the body. The threads of the stem are of different pitch than the bonnet. The fluid seal is situated so that fluid flowing into the inlet aperture and out the outlet aperture does not contact the threaded portions of the stem or body.

Abstract: A stem seal assembly comprises a stem having a top end and a bottom end. The stem is adapted to fit in a valve body and interface with the valving member. A ball segment integral to the stem has a top surface facing upwardly and a bottom surface facing downwardly. A first seal engages the top surface of the ball segment and the second seal engages the bottom surface of the ball segment.

Abstract: A valve device includes a valve stem 2 vertically movably inserted in a packing box 1a; a gland packing 6 interposed between the packing box 1a and the valve stem 2; a packing follower 15 disposed on the gland packing 6; and one or more arched plate springs 19 for pressing the gland packing 6 via the packing follower 15 or a packing flange 7 disposed on the packing follower 15.

Abstract: A packing system for valves includes a preformed packing, an upper packing cup, a lower packing cup, and a threaded bushing or a gland yoke capable of capturing the upper packing cup when the system is installed in a stuffing box. The preformed packing includes an inner cylindrical shell surrounded by an outer cylindrical shell. Two evenly spaced perforated metal sheets are provided intermediate the inner and outer cylindrical shells. The preformed packing is compressed between the upper and lower packing cups to form a tight seal around a shaft passing through the stuffing box. When the preformed packing is compressed, the perforated metal sheets engage the upper and lower packing cups. When replacing the preformed packing, simply lifting the upper packing cup away from the stuffing box will also cause the preformed packing to be lifted out of the stuffing box.

Abstract: A sealing assembly with a first molded graphite ring of generally triangular cross section, one side of which is in use perpendicular to the longitudinal axis of a rotatable and/or slidable shaft, the surface of which is to be sealed in an axial direction against fluid leakage therealong, and a second side which is in use disposed parallel to said shaft to engage the inner wall of the housing surrounding said shaft.

Abstract: A gas tap comprising an external operating element and a connecting stem for transmitting the movement of the operating element to the opening and closure member which is arranged in such a way as to be held against the sealing seat under the effect of the pressure of the gas. To make opening against the pressure of the gas easier, the operating element comprises a cylindrical sleeve which has a first screw thread that makes the sleeve move axially when the operating element is turned and a second screw thread of opposite hand to the first screw thread and with different screw pitch so as to alter the effect brought about by the first screw thread.

Abstract: A valve comprises a one piece valve body defining a fluid passage in which a closure member is disposed for selectively allowing and blocking fluid flow therethrough. A top entry stem extends into the valve body to transmit motion to the closure member. An integral external retainer is provided for cooperating with an outer abutment surface of the stem to prevent the same from being blown out of the valve body during use. A thrust bearing is disposed between the abutment surface of the stem and the external retained to reduce the operating torque. The one piece valve body design eliminates the joints and seals which are potential leak paths and the external retainer ensures that the thrust bearing be not influence by the temperature of the processed fluid.

Abstract: A butterfly valve having a valve body with a seat therein and a valve disc carried on a rotatable shaft such that the valve disc can be moved into and away from sealing engagement with the valve body seat is provided with a removable and replaceable seat member forming the valve body seat and a removable and replaceable sealing surface member is mounted on the valve disc which is sealingly engageable with the seat member when the valve disc is moved into sealing engagement with the valve body seat. The valve body seat preferably is sized to be press fit into a recess in the valve body and retained therein without additional fasteners. This butterfly valve can be used in a single, double or triple offset valve and the valve can be attached to a pipe in any conventional manner. The valve seat material and the sealing surface material may be solid metal, a resistant material such as nylon or Teflon.RTM. may have a metal insert or may have a high temperature insert such as graphite.

Abstract: A switch fitting, in particular a cock, ball cock, flap or likewise, with a switch rod for a switch member, which is rotatably and slightly tiltably guided in a switch shaft bore of a fitting housing and which has a sealing surface which is formed on a collar on the side opposed to the switch member, with a sealing ring cooperating with the sealing surface and being supported on a graduation of the switch shaft bore, and with a spring pressing the sealing surface against the sealing ring, wherein the sealing ring has essentially a fine contact with the sealing surface.

Abstract: A valve stem has a thickness of hardfaced material on its outer diameter in the area contacting the stem packing where the seal is formed which prevents corrosion, erosion and/or scratching of the valve stem, thereby preventing formation of leak paths.

Abstract: A valve gear comprises a valve 1 having a valve element and a valve stem, and an actuator having a driving shaft for operating the valve element of the valve. A connecting portion 7 is provided on either the valve or the actuator. A sleeve having a smooth inner surface is fixedly or rotatably fitted in a bore formed in the connecting portion 7 so as to slidably receive the valve stem and the driving shaft and slidably contact the inner smooth surface of the sleeve with outer surfaces of the valve stem and the driving shaft. The valve stem and the driving shaft inserted into the sleeve through the opposite ends, of the sleeve are provided at their end portions with respective coupling portions, so that the stem and the shaft are able to engage with each other only at the particular one point of relative rotation of the stem and the shaft.

Abstract: A gas valve has a solenoid actuator which is energized to open the valve an de-energized to permit spring closure of the valve. A seal element is secured on the armature of the solenoid armature. The seal element has a skirt portion which sealingly engages an armature sleeve to inhibit exhaust gas vapors from entering the chamber housing the solenoid coil and electronic sensing elements. The solenoid actuator has a pole piece defining one end of the chamber. A plurality of vent slots formed in the pole piece provide communication to atmosphere for the chamber to permit removal of any inadvertent intrusion by moisture or vapor.

Abstract: A valve device comprising a body (1), a closure member (2) operated by a shaft (3) guided through a neck (4) in the body (1), and a liner (5) provided with a flange (6) extending along part of the length of the neck (4). The sealing contact between the shaft and the bore may be improved by means of a clamping assembly (7, 8, 9) positioned around the flange (6) in a space (10) in the body (1). The size of the clamping assembly (7, 8, 9) is such that it exerts a force on the flange (6) and thereby on the shaft (3). The clamping assembly (7, 8, 9) is radially and/or tiltably movable in said space (10) relative to the body (1). Said device is particularly suitable for butterfly valves for use with corrosive and/or delicate liquids such as liquid chemicals and liquid foodstuffs.

Abstract: The valve comprises an operating wheel connected by a connecting rod to an opening and closing member. The valve is sealed by a stuffening box fixed into the upper part of the body around the rod. The stuffening box has a polygonal head so that it can be screwed and unscrewed. However the head is not accessible using a conventional spanner so as to prevent a non-specialist form slackening of the stuffing box and avoid him risking an accident.

Abstract: A valve stem sealing device used for preventing oil from entering a combustion chamber through a gap formed between a valve guide and a valve stem is disclosed. The valve stem sealing device comprises an annular oil seal surrounding a valve stem and an annular support member fixed to the top of the valve guide so as to hold the oil seal in its place, wherein the support member has an inwardly opening annular recess and rotatably receives the oil seal in the recess, with a bearing being positioned between said oil seal and the side wall of the support member. In addition, a rubber member is tightly interposed between the support member and the valve guide so as to absorb the vibrations caused by a valve operation. Also, a support cap covers the outside wall of the oil seal so that the outside wall of the support cap is brought into contact with the bearing.

Abstract: Disclosed is a valve assembly having a slidable valve stem that passes through a bushing enclosed in a bonnet. At least one circumferential stem seal seals the valve stem to the bushing. At least one passageway is provided through the bushing for injecting a fluid between the valve stem and the bushing to wash out deposits. A second optional passageway is also provided for injecting a lubricant around the valve stem.

Abstract: A valve arrangement including a housing (2) and a shut-off element (8) with which a shaft (10) is rotatably coupled, the passage of the shaft through the housing (2) being sealed by a sealing element (32). In addition to the first sealing element (32), which is disposed in an annular space between the shaft (10) and the housing (2), a second sealing element (42) may optionally be disposed at least partially within an annular body (3) connected to the housing (2). The valve arrangement is provided in the interior of the housing with a lining (20, 21). The lining (20) of the housing (2) extends at least to the first sealing element (32) with which it is in direct contact. The first sealing element (32), and the optional second element (42), if present, can be compressed by a bushing (48) which is movable axially along the shaft (10). The valve arrangement of the invention has the advantage that it can be upgraded at low manufacturing cost to minimize leakage rates and satisfy strict safety requirements.

Abstract: A piston valve for use in connection with the fire protection industry is disclosed which includes features for protecting against corrosion. A sacrificial zinc anode is mounted in the body of the valve under the handwheel. A polymeric piston is used which cannot corrode. A grease fitting protects against corrosion at the interface of the spindle and the valve body or bushing within the body.

Abstract: A shaft device for a valve, comprises a shaft supported in a bearing and extending into a relatively warm space, a sleeve provided between the shaft and the bearing, and cooling channels arranged in the border area between the shaft and the sleeve for cooling of the bearing, and wherein the axial length of the sleeve is longer than the axial length of the bearing.

Abstract: A ball valve includes a hollow valve body for mounting a valve ball therein. A drive transmitting stem has a proximate end coupled to the valve ball, and a distal end extending outwardly of the valve body for coupling with an output drive shaft of a valve control device. A hollow bearing housing of a single-piece construction is sleeved spacedly on the stem, and has a mounting end inserted into the valve body, and a support end for supporting securely the valve control device. An annular packing member, a tensioning member and a bearing member are mounted sealingly on the stem and are completely received in the bearing housing. As such, the ball valve can be connected directly to the valve control device through the bearing housing without the need for a connecting bracket.

Abstract: A bushing for a railroad control valve composed of aluminum having an anodized surface with a teflon layer at least where a valve element moves within the bushing. The teflon is preferably impregnated into the anodized surface or may be a continuous teflon sheet bound to the anodized surface.

Abstract: A gas distribution valve including a body defining an inlet and an outlet passage, a central well containing a cylindrical plug disposed for arcuate displacement therein and including a transverse thru-bore that can be rotated into and out of axial alignment with the flow passages of said body for opening and closing the valve respectively. Overmolded elastomeric seat seals are provided for superior sealing that are urged against the well walls by an arcuate leaf spring intervening between the seals and the plug and extending in a direction concentric with the plug. A cover plate secures the plug within in the well and there is afforded a fire seal ring providing bi-directional contact sealing operative to restrict gas flow during and after exposure to fire or other high temperature environment.

Abstract: A variable bore ram packer designed for use in a standard ram-type blowout preventer used in oil and gas drilling operations is disclosed. The variable bore ram packer includes top and bottom second plates having a central semi-circular opening which is sized to fit closely about the largest diameter pipe the variable bore ram packer will seal against. Anti-extrusion plates having a smaller central arcuate opening sized to fit closely the smallest diameter pipe the variable bore ram packer will seal are attached to the underside of the top plate by guide screws. The guide screws extend through slots in the top plates which control the motion of the guide screws and hence the anti-extrusion plates as the anti-extrusion plates move and seat against different diameter tubular members.

Abstract: A non-riser valve assembly 30 includes a bonnet or housing 32, a bushing 34, a stem 36, a washer 38 and a stop 40. The assembly 30 further includes a coupling 42, a rotatable or movable disk 44, a fixed disk 46 and a bottom seal 48. In assembly, the bushing 34 and the stem 36 are located within an opening 50 of the housing 32 with the bushing being located between the housing and the stem. One of the stem 36 extends from one end of the opening 50 and the stop 40 is removably attached to the stem to limit the rotational movement of the stem within the housing. The coupling 42 is located in the opening 50 of the housing 32 and is in driving engagement with the opposite end of the stem 36. The movable disk 44 is located with the opening 50 and is coupled to the coupling 42 for rotation therewith. The fixed disk 46 is attached to the housing 32 within the opening 50 and is formed with a surface 224 which is in water-sealing engagement with a surface 162 of the movable disk 44.

Abstract: A device for preventing a polygonal gland nut helically coupled with the stem of a valve from loosening includes a locking piece inserted non-rotatable on the stem. A pair of engaging claws are formed on the locking piece to engage with one of the lateral faces of the gland nut and also with two lateral faces of the gland nut adjoining each other straddled an intervening corner of the gland nut.

Abstract: A valve includes a column having an outer end portion defining a threaded bore, an outer mediate portion defining a first receiving recess communicating with the threaded bore, an inner mediate portion defining a passage communicating with the first receiving recess, and an inner end portion extending outwardly from a valve body and defining a second receiving recess communicating with the passage, and a valve stem having a first end portion formed with an outer thread, and a second end portion extending through the passage and formed with an annular flange received in the second receiving recess.

Abstract: A valve and actuator in combination with a transportation tank to operate off of low pneumatic pressures including a valve having a valve body with a tank end, a valve seat near the tank end of the valve body, the valve seat having a valve sealing surface; a stem chamber extending through the valve body, the stem chamber having an actuator port, a seat port, and an outlet port; a valve stem slidably positioned in the stem chamber, the valve stem having a plug end and a plug attached to the plug end, the plug having a plug sealing surface to sealingly contact the valve sealing surface; an actuator having a hollow housing with a valve end, the valve end attached to the valve body; a plurality of piston assemblies, each having a piston slidable in the housing and a partition fixed in the housing, the piston and the partition defining an actuator chamber; piston spacers joining the pistons so that each piston is fixed in position with respect to the others; the pistons being operatively joined to the valve stem;

Abstract: An apparatus for injecting sealant into the packing chamber of a valve requiring no venting of pressure within the valve. The apparatus which includes an interior valve is attached to the valve body by drilling and tapping a connection or by friction welding. A high pressure packing gland is attached to the apparatus and a drill bit is passed through the combination to complete an opening into the packing chamber. The drill bit is withdrawn past the interior valve, which is closed and then out of the combination. The packing gland is removed and a sealant injection device attached. The interior valve is opened and sealant injected into the packing chamber. The valve is closed, a completion plug installed into the end of the fitting, and a completion cap with a sealing ring is installed over the entire valve and fitting, thereby forming multiple redundant seals.

Abstract: A back seat rising stem gate valve has a valve body with a flow passageway through it and an open top, a gate that is vertically positioned to open and close the passageway, a stem extending upwardly from the valve body, the lower end of the stem being attached to the gate, a bonnet secured to the valve body by which the valve body open top is closed, the stem extending through an opening in the bonnet, a packing box slidably positioned in an opening in the bonnet and receiving the stem, the packing box having a back seat circumferential sealing surface surrounding the valve stem, and the valve stem having an integral enlarged diameter shoulder so that when the stem is in the full upward position the packing box can be displaced downwardly forcing the back seat sealing surface to seal against the stem shoulder to seal against fluid leakage along the valve stem. In one embodiment the packing box is downwardly displaced by hydraulic pressure, such as hydraulic pressure supplied from within the valve body.

Abstract: An improved ball valve for lethal gas or fluid service is disclosed having a novel triple redundant stem to bonnet seal design. A ceramic seal ring forms the primary stem to bonnet seal. The ceramic seal ring has a first seal surface lapped for sealing engagement with a corresponding lapped surface on the stem and a second seal surface lapped for sealing engagement with a corresponding lapped surface on the bonnet. The ceramic seal ring first seal surface lapped for sealing engagement with a corresponding lapped surface on said stem and the corresponding lapped surface on the stem may be frustoconically or spherically shaped. An elastomeric seal and a compression type seal between the stem and bonnet act as redundant seals. A preloading means to maintain the ceramic seal ring and lapped sealing surfaces on the bonnet and stem in sealing engagement is shown.

Abstract: The maintenance method is for a gate valve. The method comprises the steps of closing the gate valve; removing sequentially the hand wheel, the gland flange, the gland and the packing from the stem of the gate valve; mounting a first clamp onto the gate valve to keep the disc of the valve in an obturating position; untying the packing box and sliding it at least partially along the stem. The method further comprises the steps of removing the packing ring from the shouldering of the stem; mounting a second clamp onto the gate valve to keep the disc in the obturating position; removing the first clamp from the stem; sliding and removing the packing box and the packing ring from the stem; inserting a new packing ring along the stem; putting back the packing box along the stem; mounting again the first clamp onto the gate valve; removing the second clamp from the shouldering; and positioning the new packing ring onto the shouldering of the stem.