Abstract: A degassing valve in a flexible container is disclosed. The valve includes a generally flat valve seat on a truncated generally dome shaped structure, and the valve seat is raised a height above the valve chamber base surface. A resilient, non-perforated, non-spring-biased diaphragm is inter-engaged upon the valve seat and overlaps the valve seat outer periphery. The valve seat engages a central area of the diaphragm that is not proximate the perimeter of the diaphragm, and the dome shaped structure has a sectional radius greater than the diaphragm radius. A well is recessed into the valve seat in a direction away from the diaphragm by a depth less than the height of the valve seat above the valve chamber base surface.

Abstract: A valve for controlling a fluid includes a valve seat and a closing body which has a spherical-cap-shaped end region and which is configured to open up and close off a passage at the valve seat. The closing body is rotatably mounted on a bearing and has at least one contouring formed on a surface of the closing body. The contouring is configured to set the closing body in rotation.

Abstract: A vacuum valve with a seating ring having a generally rectangular cross section. With respect to rectangular edges lying diametrically opposite one another, radii of curvature are arranged in these edges, which radii of curvature come into sealing engagement with sealing seats arranged lying opposite one another on the housing side and the disk side. The sealing surfaces on the sealing seats have approximately the same cone angle. The sealing ring is easy to produce, has a small rolling path and there is no danger of damage to the valve seats by the sealing ring.

Abstract: A layered adaptive membrane structure that has movable membranes is provided. The structure can change its gas, liquid and/or particulate permeability in response to surrounding environmental conditions. Applications include protective apparel that is comfortable to wear wherein the level of protection provided is based on conditions in the environment. Hence, the protective apparel is highly breathable and comfortable in a non-hazardous environment but impermeable or only semipermeable in a hazardous environment.

Abstract: The invention refers to a valve, in particular a pressure valve, comprising a feed area provided in front of a globe valve in flow direction of the medium, wherein the globe valve can be sealed by a loose closing element provided in the feed area, and wherein an activation rod angles the closing element against the flow direction of the medium with reference to the globe valve. The invention is characterized in that in the feed area a flow guiding device is provided, wherein the flow guiding device has several channel areas, so that the medium flowing through the channel areas is set in a helical twist.

Abstract: A three-way poppet valve that can restrict or eliminate backflow without the use of an external check valve. Unlike conventional three-way poppet valves wherein both inlets can be open to the outlet at the same time during movement of the poppet, the valve according to the present invention can be configured to close both inlets prior to opening one of the inlets to the outlet. The valve features a poppet valve assembly that is operable to prevent both inlets from being open to the outlet at the same time. The valve assembly also reduces the force needed to close the valve against at least one of the inlets thereby allowing the use of a smaller actuator. A unique seal including a valve seat that is configured to conform to a valve member under sufficient pressure.

Abstract: An air intake device for an engine is provided that includes a bypass (20) connected to an air intake path (2) while bypassing a throttle valve (5), and a bypass valve (V) for controlling the degree of opening of the bypass (20), the bypass valve (V) being formed from a tubular valve chamber (15) having its interior opening on the upstream side of the bypass (20) and having an inner face with a metering hole (16) opening toward the downstream side of the bypass (20), and a valve body (25) slidably but non-rotatably fitted into the valve chamber (15) and opening and closing the metering hole (16), wherein an inner face (A) of the valve chamber (15) on which the metering hole (16) opens and an outer face (B1) of the valve body (25) opposing the inner face (A) and covering the metering hole (16) are formed in the same shape so as to enable them to be in intimate contact with each other, and other inner (A) and outer faces (B2) of the valve chamber (15) and the valve body (25) are formed so that there is a gap (g

Abstract: A check vacuum breaking device for a tap includes a locking member screwed into a chamber of a tap. The chamber includes an inlet and an outlet. The locking member includes a cover member secured on a top end thereof and having plural air bores disposed around a rim of the cover member, and a shaft extends downward from a center of a bottom surface of the cover member. A fitting member is assembled to the chamber of the tap and includes a hollow peg extending upward from a central portion thereof and having a closed bottom to be fitted to the shaft of the locking member. The hollow peg includes a stepped recess formed on an upper end thereof, and a stopping pad is fitted to the stepped recess. The fitting member includes an annular loading member fitted to a lower end thereof and an anti-leak loop to cover the loading member.

Abstract: A pilot valve is provided with a conical first contact surface, and a pilot valve seat is provided with an annular second contact surface of which an initial contact portion with respect to the first contact surface has a circular-arc cross-section. The first contact surface is formed of a resin with elasticity, and the second contact surface is formed of metal. When a pressure-contact load is small, the first contact surface and the second contact surface come into line-contact with each other. When a pressure-contact load increases, the first contact surface and the second contact surface come into plane-contact with each other.

Abstract: A high-pressure side primary pressure chamber communicates with a secondary pressure chamber on the side of a pressure receiving device through a communication hole. A diaphragm which receives the pressure in the secondary pressure chamber is provided, and a valve body is connected to the diaphragm. The diaphragm is biased by a spring in a valve opening direction. The area S (mm2) of the pressure receiving surface of the diaphragm and the spring constant k (N/mm) of the spring are set so as to satisfy the following equations (1) and (2). P1×S?k×?L>C??(1) P1<P2??(2) where P1 denotes the pressure (MPa or N/mm2) of the secondary pressure chamber, ?L denotes the displacement (mm) of the spring, C denotes the minimum closing load (N) of the valve body, and P2 denotes the allowable maximum pressure (MPa or N/mm2) of the pressure receiving device.

Abstract: A membrane valve comprising a first and a second valve housing part and a membrane clamped between the valve housing parts comprises a peripherally surrounding bead on the membrane and a thin, axially movable membrane portion adjacent thereto. The bead is supported by the two valve housing parts and is provided with an undercut at a radial inner side. Further, a membrane for installation in a membrane valve is provided.

Abstract: A control valve device develops opening/closing accuracy of a valve assembly. The valve head 310a is configured to open and close a transfer path formed in the valve housing 305 by transmitting the power to the valve assembly 310 from the power transmission member according to a pressure ratio between working fluid supplied to the first space Us and the second space Ls, respectively. The valve head has a Vickers hardness larger than a Vickers hardness of a valve seat of the transfer path to be in contact with the valve head, and a hardness difference therebetween is set to be about 200 Hv to about 300 Hv.

Abstract: A steam supply passage incorporates a pressure reducing valve and the passage further incorporates a steam ejector downstream of the pressure reducing valve. A suction portion of the steam ejector is connected to a re-evaporation tank for re-evaporating steam condensate via a suction passage. Passage steam of the pressure reducing valve is used as a driving steam for the steam ejector. In operation, re-evaporated steam within the re-evaporation tank is suctioned by the steam ejector to be mixed with the passage steam. The suction passage incorporates a check valve for preventing reverse flow of steam to the re-evaporation tank.

Abstract: An illustrative valve is disclosed that includes a valve body, a valve seat disposed within the valve body that has a first curved sealing surface and a valve member having a second curved sealing surface that is adapted to sealingly engage the first curved sealing surface, wherein the first and second curved sealing surfaces are opposed curved sealing surfaces.

Abstract: An electronically controlled stepper motor valve utilizes an electric feed through assembly providing electrical connection between the stepper motor and a mating cable connector; wherein the electric feed through assembly includes four individual leads that are sequenced to allow the mating cable connector to be installed in any of four positions, each 90 degrees apart. The ability to use a 90 degree elbow style cable connector allows the EEV footprint to be minimized which provides an advantage when the electric expansion valve is installed in the tight confines of a package system.

Abstract: The present invention relates to valve plugs for reducing erosion of the valve plug head and/or seat. More specifically, this invention comprises a valve plug incorporating a choke transfer trim that reduces the time of exposure of the plug head and/or seat to high velocity and high pressure drop at the interface of the plug head and seat when the valve is in the closed position. The choke transfer trim transfers the flow control area of the valve away from the plug head/seat interface to a location downstream, thereby reducing erosion at the interface between the valve plug head and/or seat that is typically used for fluid throttling and shut off.

Abstract: A valve for controlling a fluid includes a closing body and a valve seat. The closing body opens and closes a passage at the valve seat along a sealing line. The valve seat and the closing body have a rotationally symmetrical region where the sealing line between the valve seat and closing body is formed. The valve seat and/or the closing body also has a nonrotationally symmetrical region, which adjoins the rotationally symmetrical region in a throughflow direction of the valve.

Abstract: The invention relates to a valve (100, 101) comprising a housing (110, 111), an annular sealing element (140, 146), and a displaceable closure element (170), wherein the sealing element (140, 146) and the closure element (170) are disposed within the housing (110, 111), and wherein the valve (100, 101) can be closed by placing the closure element (170) against the sealing element (140, 146). The valve (100, 101) is characterized by a hollow space (131, 132) in the region of an outer side of the sealing element (140, 146), in which a part (143, 144) of the sealing element (140, 146) can be received during thermal expansion. The invention further relates to another valve (102) in which the annular sealing element is an O-ring (150).

Abstract: A choke trim assembly for use as a shuttle seat in a choke valve including a flange sleeve is disclosed, the choke trim assembly comprising a trim, a trim carrier, and a clamp ring, wherein the trim carrier and the clamp ring each have a tubular member, an outer diameter of the tubular member of the clamp ring being configured to enable a slip fit of the choke trim assembly into an inner diameter of the flange sleeve, the trim being centered in the clamp ring, and an outer diameter of the tubular member of the trim carrier and the inner diameter of the clamp ring being configured to enable a slip fit of the trim carrier into the clamp ring.

Abstract: A pneumatic pilot valve comprises a valve body having an inlet, an outlet, a flow passage, and first and second valves arranged to control flow through the valve. The second valve includes a tapered valve seat opening into a cylindrical bore, and a thrust pin includes a tapered second part and an annular recess having a seal. The thrust pin is movable between a first position, a second position, and an intermediate position. The tapered second part of the thrust pin is arranged to engage the tapered valve seat to close the second valve when the thrust pin moves to the second position, and the resilient seal is sized to engage the cylindrical bore when the thrust pin is in the intermediate position.

Abstract: A check valve (fluid on-off valve device) capable of attaining high sealability in either case where a differential pressure is high or low, comprises a valve body assembly (valve body) contacting and separating from a valve seat portion for communicating and blocking a fluid passage. The valve body assembly comprises a valve body, a low-pressure seal portion constituted out of soft material and a high-pressure seal portion constituted out of harder material than the low-pressure seal portion. In blocking a fluid passage, when a differential pressure between an upstream path and a downstream path in the fluid passage is relatively low, the low-pressure seal portion comes into close contact with a protrusion to block the fluid passage, while when the differential pressure is relatively high, the low-pressure seal portion is compressively deformed by the differential pressure and the high-pressure seal portion comes into close contact with the valve seat body, thus blocking the fluid passage.

Abstract: A valve trim apparatus for use with valves is described. An example valve trim apparatus includes a cage having an upper portion removably coupled to a lower portion. A closure member is disposed within the cage and has a first seating surface and a second seating surface. A seal assembly is fixed between the upper and lower portions of the cage. The first sealing surface of the closure member sealingly engages the seal assembly when the closure member is in a closed position to prevent leakage between the closure member and the cage.

Abstract: The present invention relates to a microvalve having a valve plug, connecting legs, anchors and actuators, allowing the valve plug to move vertically to open or close the valve. The valve plug can contain magnetic materials, and be operated by an actuator.

Abstract: A valve body and seal assembly comprises a valve body symmetrical about a longitudinal axis and comprising a circumferential seal retention groove and a frusto-conical valve body impact area for contacting a valve seat. An elastomeric seal is cast-in-place in the circumferential seal retention groove. Each seal comprises first and second seal sections in contact via an intra-seal interface, the interface simultaneously extending radially outward and longitudinally. First seal sections may comprise a first polyurethane having a higher modulus than a second polyurethane of which second seal sections may be comprised. First seal sections are cast and partially cured in a mold which is rotating about the longitudinal axis. Second seal sections are cast after the first seal sections are partially cured, resulting in the intra-seal interface shape described above. Cross-linking between first and second seal sections across the intra-seal interface is thus facilitated.

Abstract: An aseptic diaphragm valve in which a valve seat (37) is formed by a groove including a concave surface of engagement that positioned along an outer diameter of an upper end of an inlet tube (32), and a resilient valve member portion (41) that is annular in extent with a convex surface that moves into the groove to contact the concave surface (37) around the outer diameter of the inlet tube (32) to close the valve. The valve member portion (41) has at least a coating of polytetrafluoroethylene (47) or equivalent material.

Abstract: A valve assembly comprises a valve body comprising a plug chamber. A static seal is disposed adjacent an inner sidewall of the plug chamber, and a plug comprising a plug head is moveably positioned within the plug chamber, the plug head being configured to contact the static seal only when the plug is adjacent to a seat ring. Methods of using a valve and methods of forming a valve assembly are also disclosed.

Abstract: A system for hydraulically managing fluid pressure between selected set points includes a pilot control system operably coupled to a main valve. The pilot control system includes at least one fluid conduit, a variable orifice assembly, and a control pilot valve apparatus. Fluid is passed through a fixed orifice and into a first chamber of the control pilot valve apparatus. Fluid is passed through the variable orifice of the variable orifice assembly and into a second chamber of the control pilot valve apparatus. The main valve is hydraulically opened or closed in response to a pressure differential between the first and second chambers of the control pilot valve apparatus so as to manage fluid pressure downstream of the main valve between the selected upper and lower set points.

Abstract: An unfreeze faucet structure includes a watering control valve having a body; a control shaft, an upper ceramic member, and a lower ceramic member connected with the body; a valve seat locked to the body; wherein the control shaft includes a watering cavity and a positioning groove mounted in a lower section thereof, the watering cavity includes a check element and a stopping unit installed therein, the check element includes a disk-shaped cover arranged on a bottom end thereof, the cover includes a first stop loop fitted to a peripheral side thereof, between the cover and the watering cavity is defined with a spring, the stopping unit includes a trench disposed therearound to contact with the first stop loop, the control shaft includes a second stop loop fitted on an outer periphery thereof and a third stop loop arranged therearound to engage with an inner wall of the watering cavity.

Abstract: A self-cleaning valve assembly is provided, such as for use in a vacuum cleaner such as a particularly advantageous vacuum cleaner system that has at least two filters and self-cleans its filters via back-flushing, without needing to stop normal operation to self-clean. Also, a vacuum cleaner is provided that uses permanent, self-cleaning filters, and does not need disposable filters or filter bags, and advantageously can use inexpensive plastic bags. In another vacuum cleaner system, waste is collected in an ordinary plastic bag without any special preparation or modification of the bag being needed. Further, an inventive self-cleaning X-valve assembly cleans itself and is useable in the vacuum cleaner system.

Abstract: A flow valve includes a control valve having a movable body, a stop valve having a movable body; and a valve seat having a facing surface that contacts at least a portion of one of the control valve body or the stop valve body when the flow valve is in a closed position, the facing surface of the valve seat being configured to merge with a rear portion of the valve seat at a tip portion, the facing surface of the valve seat having an aerodynamic profile that provides for a guided flow in a flow direction through the flow valve.

Abstract: A fluid control device with a non-circular flow passageway is disclosed. The fluid control device has an inlet port (318) formed on a first side (314) of a fluid control body. A valve cavity (320) is formed in the bottom of the fluid control body. The inlet port is coupled to the valve cavity with an inlet port opening. A valve seat (316) is formed in the valve cavity with a non-circular shaped valve seat passageway (310). An outlet port (306) is formed on a second side (312) of the fluid control body. The outlet port is coupled to the non-circular shaped valve seat passageway (310) by an outlet port passageway (308).

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

Abstract: This valve (100) comprises: a body (101); a first channel (III) for channelling the flow of a fluid; a second channel (112) for channelling the flow of a fluid; a first valving element (130) which is movable translationally in a first direction (X112), between an open position and closed position of the or each first channel (111), the body (101) fouling a first seat (123) for the first valving element (130); and a second valving element (130) which is movable translationally in a second direction (X112), between an open position and a closed position of the or each second channel (112); the first direction (X112) and the second direction (X112) being parallel or coinciding with each other. The first valving element (130) defines a housing (140) for the second valving element (130). The first valving element (130) forms a second seat (136) for the second valving element (130).

Abstract: A capacity control valve includes a valve body having a first valve portion for opening/closing a discharge-side path and a second valve portion for opening/closing a suction-side path, a pressure sensitive body arranged in a third valve chamber in the middle of the suction-side path, a valve seat body provided at the pressure sensitive body, and a third valve portion connected to the valve body for opening/closing the suction-side path by engagement and disengagement with the valve seat body. One of an engagement face of the third valve portion and a seat face of the valve seat body is formed into a spherical shape with a radius of curvature R satisfying 9 mm<R<11 mm and the other of the engagement face of the third valve portion and the seat face of the valve seat body is formed into a tapered surface shape having a center angle ? satisfying 120°<?<160°.

Abstract: A fuel system component is provided. The fuel system component may comprise a valve body having a substantially conical surface region including a first coating. The component may further include a valve seat having a first surface region with a substantially conical surface including a second coating. The coating of the valve seat is configured to engage at least a portion of the coating of the substantially conical surface region of the valve body.

Abstract: An adaptive membrane structure is provided. The adaptive membrane structure has movable membranes that can be made to change its gas, liquid or particulate permeability in response to surrounding environmental conditions. Such adaptive membrane structures can be used to provide protective apparel that is comfortable to wear wherein the level of protection provided is based on conditions in the environment. The adaptive membrane structures can be used to provide protective enclosures.

Abstract: A device in a valve (1) comprises a valve housing (2) with at least a first (3) and a second (4) fluid port. A closure element (5) is arranged in the valve housing (2), said closure element (5) having a sealing portion (15) and comprising a diaphragm (30). The sealing portion (15) is movable along an axis of the closure element (5) by said diaphragm (30) between an open position and a closed position of at least one of the fluid ports of the valve housing. The closure element (5) together with the valve housing (2) forms a flow passage (11) in the valve housing (2) which communicates with said fluid ports when the sealing portion (15) leaves said closed position. A second sealing portion (14) of the closure element, which is an enclosing portion spaced from said axis, is arranged in contact with a support portion (25) of the valve housing (2).

Abstract: An intake valve for a cylinder of the high-pressure fuel pump of a common rail injection system has a valve body with an inlet opening and a closing member. The closing member closes the inlet opening in a first end position. The member can be moved relative to the inlet opening depending on a pressure difference. The intake valve has a non-linear volumetric flow characteristic.

Abstract: A puck retaining recess in a plunger of a solenoid valve is formed with a puck retaining lip that is fixed or unified with the plunger. The puck is then radially compressed to fit through a central opening of the retainer lip, and once the puck is pushed past the retainer lip, it is allowed to radially expand within the recess where the puck is retained between a bottom of the recess and the retainer lip. This eliminates many problems that previously occurred with separable retainer lips pressed into position to hold a puck after its insertion into a plunger recess.

Abstract: A valve system includes a source of pressurized fluid comprising an orifice through which the pressurized fluid flows away from the source, and a poppet comprising a groove and a seal positioned in the groove, wherein the seal plugs the orifice when the poppet is in a closed position, and wherein the poppet and the seal move through the orifice against a flow of the pressurized fluid to allow the pressurized fluid to flow through the orifice and away from the source. The seal may include an O-ring.

Abstract: Self-contained disposable cryosurgical devices dispense a cryogenic fluid, such as a stream of liquid nitrous oxide, carbon dioxide or argon. The cryosurgical devices include a container, including a reservoir containing a cryogenic fluid, a flow passage configured to receive the cryogenic fluid from the reservoir, a valve assembly configured in an ergonomic housing, and a dispensing head. The device further includes at least one filter disposed in the flow passage configured to facilitate the flow of the cryogenic fluid. The valve assembly includes a valve body and valve slide that is actuated to effect the flow of the cryogenic fluid through the flow passage to patient target. The housing includes an activation lever with an eccentric hub that primes the device for use when a container is loaded into the housing and the activation lever is closed.

Abstract: Methods and apparatus to align a seat ring in a valve are described. An example fluid valve includes a valve body having a curved internal surface to receive a seat ring and a seat ring having a sealing surface to receive a movable control member and a curved surface opposite the sealing surface to engage the curved internal surface of the valve body.

Abstract: The present invention relates to a multilayer protective enclosure for protecting humans, animals or perishables from hazardous agents in the environment. The enclosure contains a porous adaptive membrane structure that has movable membranes with insertable protrusions. The structure can be made to change its gas, liquid or particulate permeability in response to surrounding environmental conditions. Hence, the enclosure is highly breathable in a non-hazardous environment but impermeable or only semipermeable in a hazardous environment.

Abstract: In a microvalve, a valve seat includes a cylinder portion that includes a through hole in a central portion thereof, and a flange portion that is provided around an axial end of the cylinder portion and that has a thick seal portion on a periphery of the flange portion. The cylinder portion is disposed in an opening of a valve housing with a gap ? therebetween, and the seal portion is able to move away from the seal surface provided around the opening and away from the displacement member. In an open state, at least one of a flow path through the through hole and a flow path through the gap between the cylinder portion and the opening is open, and in a closed state, the seal portion is sandwiched between the displacement member and the seal surface.

Abstract: An unfreeze faucet structure includes a watering control valve having a body; a control shaft, an upper ceramic member, and a lower ceramic member connected with the body; a valve seat locked to the body; wherein the control shaft includes a watering cavity and a positioning groove mounted in a lower section thereof, the watering cavity includes a check element and a stopping unit installed therein, the check element includes a disk-shaped cover arranged on a bottom end thereof, the cover includes a first stop loop fitted to a peripheral side thereof, between the cover and the watering cavity is defined with a spring, the stopping unit includes a trench disposed therearound to contact with the first stop loop, the control shaft includes a second stop loop fitted on an outer periphery thereof and a third stop loop arranged therearound to engage with an inner wall of the watering cavity.

Abstract: A steam valve is provided with a valve body, a valve seat, and a valve rod provided for the valve body. The valve body has a bottom portion to which a recessed portion is formed, and the recessed portion has an edge, which is positioned on an upstream side of a place at which a shock wave is generated in steam flowing through a steam path defined by the valve body and the valve seat.

Abstract: A presettable gas valve is disclosed herein. The gas valve may have a maximum gas flow that can be adjusted to the particular requirements of the fireplace in which the gas valve is used. By way of example and not limitation, for real biomass/fuel burning fireplaces, the gas valve may be opened to its maximum level with a quarter turn of a handle. In contrast, for fake fireplaces, which require more gas flow compared to real fireplaces, the gas valve may be opened to its maximum level with a half turn of the handle. The maximum gas flow through the gas valve may be set during installation such that the user does not need to manually determine the appropriate amount of gas during use.

Abstract: The invention relates to a micro-valve (1) comprising a valve ball (2), a valve seat (3) and a nozzle (14). In said valve, the valve seat (3) comprises a sealing region (5) and an outlet region (6) and guide means (40) are provided on the valve seat. The guide element is configured in the valve seat (3) in the form of a guide region (4) or a one-piece guide element (40) located in the vicinity of the valve seat (3). The micro-valves according to the invention exhibit substantial improvements with respect to dynamics, life cycle and stream pattern, In first embodiments, increased wear-resistance is achieved by the integration of guide means, in the form of a guide region (4), into the valve seat, optimizing the dimensions of the transition angle, guide angle and discharge angle. In versions comprising a one-piece guide element (40), wear is reduced by the fact that the ball primarily carries out a sealing function and a guide function to a lesser degree.

Abstract: A three-way poppet valve that can restrict or eliminate backflow without the use of an external check valve. Unlike conventional three-way poppet valves wherein both inlets can be open to the outlet at the same time during movement of the poppet, the valve according to the present invention can be configured to close both inlets prior to opening one of the inlets to the outlet. The valve features a poppet valve assembly that is operable to prevent both inlets from being open to the outlet at the same time. The valve assembly also reduces the force needed to close the valve against at least one of the inlets thereby allowing the use of a smaller actuator. A unique seal including a valve seat that is configured to conform to a valve member under sufficient pressure.

Abstract: A double seat valve in which a second closing element (4), in its closed position, rests with a stopping surface (4f) on a face of its cylindrical projection (4*) directly upon a first seat (2a) and, together with a peripheral wall (4c, 4h), forms a second wraparound edge (U2) upon an interface (2e, 2e*). The peripheral wall (4c), at its end facing away from a first closing element (3), merges into a rotationally symmetric reversing surface (4d) that leads to a face (4e) of a recess (4b) oriented essentially perpendicular to the longitudinal axis of the second closing element (4). In meridian section, the reversing surface (4b) has a contour (K) with a bend-free curve, a direction vector in the leading point of the reversing surface (4d) points into a discharge borehole (3d, 3d*) central in the first closing element (3) without colliding with the first closing element (3) in the vicinity of its areas bordering the leakage cavity (5) and forming dynamic pressure.