Abstract: A single magnetic coil floating plunger redundant gas valves is disclosed. In an illustrative embodiment, the valve may include a first plunger tube, a second plunger tube spaced a distance from the first plunger tube, a magnetic coil disposed about at least part of the first plunger tube, a first plunger disposed within the first plunger tube, and a second plunger disposed within the second plunger tube. The first and second plungers may be operatively coupled to first and second valve members. Activation of the magnetic coil may result in the first and second plungers being suspended in the plunger tubes without a hard mechanical plunger stop to selectively open corresponding valves or other actuatable components, as desired.

Abstract: A method of fabricating an elastomeric structure, comprising: forming a first elastomeric layer on top of a first micromachined mold, the first micromachined mold having a first raised protrusion which forms a first recess extending along a bottom surface of the first elastomeric layer; forming a second elastomeric layer on top of a second micromachined mold, the second micromachined mold having a second raised protrusion which forms a second recess extending along a bottom surface of the second elastomeric layer; bonding the bottom surface of the second elastomeric layer onto a top surface of the first elastomeric layer such that a control channel forms in the second recess between the first and second elastomeric layers; and positioning the first elastomeric layer on top of a planar substrate such that a flow channel forms in the first recess between the first elastomeric layer and the planar substrate.

Abstract: A double water-seal accumulator used in a perfume dispenser includes a casing defining a vertical guide groove, an adapter defining a vertical guide hole and transverse guide groove, a stop ball supported on a spring member in the vertical guide hole and forced by the spring member to block the passage between the vertical guide hole and the transverse guide groove, a shaft member mounted in the casing and defining therein an angled hole and having a bottom raised portion, and an operating member coupled to the shaft member and operable to rotate the shaft member to a predetermined position where the angled hole is kept in communication with the vertical guide groove and the raised portion is stopped against the stop ball to open the passage between the vertical guide hole and the transverse guide groove.

Abstract: A conveyor warewasher for washing wares includes a first tank including a drain system having a drain outlet and a drain stop movable between a drain outlet closed position and a drain outlet open position. A second tank includes a drain system having a drain outlet, an associated drain path that leads to the first tank and an associated drain path stop moveable between a drain path open position and a drain path closed position. A drain control assembly includes a common drain actuator operatively connected to cause both (i) movement of the drain stop from the drain outlet closed position to the drain outlet open position and (ii) movement of the drain path stop from the drain path closed position to the drain path open position.

Abstract: The invention relates to a shut-off device comprising a housing which is to be connected to an adjacent conduit in a pressure-tight manner. A tubular passage is defined in the housing for a medium flowing through the conduit. Said device also comprises at least one sealing body which can be displaced by an articulated mechanism, by means of an adjusting drive that can be moved vertically in relation to the direction of flow, from an open position into a closed position in which the sealing contour of the at least one sealing body comes into contact with the tubular passage in a radially sealing manner. The articulated mechanism is guided parallel to the direction of displacement of the adjusting drive and comprises a bearing body to which the at least one sealing body is pivotably applied.

Abstract: The invention relates to a fuel gas supply system for a power-consuming member, particularly a gaseous hydrogen supply system for a fuel cell or a heat engine, the system including at least one upstream end comprising a movable mechanical actuator for selectively controlling the opening of an insulation valve of a pressurized fuel gas tank to be coupled to the at least one upstream end, the supply system including a member for controlling the movement of the mechanical actuator, characterized in that the control member is mechanically connected to the actuator via a selectively movable mechanical movement transmission member, the control member being offset relative to the actuator so as to remotely ensure the offsetting of the actuator via mechanical forces.

Abstract: A valve system that includes (i) first and second longitudinally facing members defining a gap therebetween in fluid communication with transversely offset first and second orifices through the members, (ii) a primary biasing means longitudinally biasing the members away from one another, (iii) an elastic element positioned within the gap between the first and second orifices, and (iv) a repositioning means for longitudinally repositioning one of the members towards the other member against the bias of the primary biasing means for adjusting the longitudinal height of the gap. The members can be repositioned between (a) a first position wherein the elastic element does not seal the gap so as to allow fluid flow from the first orifice to the second orifice through the gap, and (b) a second position wherein the elastic element is compressed between the members and seals the gap so as to prevent fluid flow from the first orifice to the second orifice through the gap.

Abstract: An apparatus for performing multi-dimensional assays using a microfluidic chip is presented. The apparatus comprises of two crossing series of micro-channels on the microfluidic chip. The apparatus further comprises of a plurality of magnetic valves placed at the crossings and a guiding magnet. When an operator places the guiding magnet in a vicinity of the chip, the guiding magnet produces a proximal magnetic field gradient at a location of each of the plurality of magnetic valves. At the first micro-channel crossing, a magnetic valve controls fluid flow in the first micro-channel, and another magnetic valve controls fluid flow in the second micro-channel at the first micro-channel crossing. Each magnetic valve comprises a magnetic bead and a cavity on the chip next to a corresponding micro-channel section.

Abstract: A digital flow control assembly for controlling the volumetric flow rate of fluids includes a fluid flow conduit, a plurality of serially-arranged flow nodes positioned along a length of the fluid flow conduit, and a device for generating a signal. The device for generating a signal is used to adjust one or more of the plurality of serially-arranged flow nodes to maintain a desired volumetric flow rate of fluid in the fluid flow conduit. A method for controlling the volumetric flow rate of fluids includes providing a fluid flow conduit, providing a plurality of serially-arranged flow nodes positioned along a length of the fluid flow conduit, and providing a feedback signal to adjust one or more of the plurality of serially-arranged flow nodes to maintain a desired volumetric flow rate of fluid in the fluid flow conduit.

Abstract: A variable flow valve is provided. The variable flow valve includes a housing, an actuator, a biasing agent, positioning coils, and a locking coil. The housing defines a bore, an inlet, and an outlet. The actuator is moveably disposed within the bore and configured to selectively obstruct and expose the outlet. The biasing agent is disposed within the bore. The biasing agent is also interposed between the housing and the actuator to bias the actuator toward the outlet. The positioning coils are disposed about the housing and operable to drive the biasing agent to a retracted position. The locking coil is disposed about the housing proximate the biasing agent. The locking coil is operable to capture the biasing agent in the retracted position. As such, the positioning coils are thereafter able to move the actuator free of the bias from the biasing agent.

Abstract: The invention relates to a tap (1) for a pressurized gas cylinder, that comprises a body (2) to be connected to a gas (G) outlet opening (3) of a gas cylinder (4), un gas (G) off-take circuit (C) including at least one gas outlet (5, 25), at least one valve (6) movable between a circuit (C) closing position and a circuit (C) opening position, at least one member (23) for adjusting the release flow of the gas (G), and a single actuation member (9) capable of interaction both with the valve (6) and with the flow adjustment member (23), characterized in that the actuation member (9) is mounted so as to be movable relative to the body (2) according to two distinct movements, said actuation member (9) being arranged relative to the valve (6) and the flow adjustment member (7) so that the two types of movements respectively control the movement of the valve (6) between the opening and closing positions on the one hand and the flow adjustment member (23) on the other hand.

Abstract: The invention relates to a double-seat valve, the seats of which can be cleaned, which is improved compared to the prior art in that discharge of the seat cleaning flow into and out of the leakage cavity as much as possible without turbulence is ensured, and pressure-increasing direct action on the seat areas is reliably avoided.

Abstract: Sink spray head with supply jet variation and flow rate regulation, comprising a body defining at least two distinct water supply areas in communication with a distribution chamber controlled by a diverting cut-off driven by means of two distinct selection keys accessible outside the body, a cut-off being also provided for the regulation of the water flow rate. The keys are operatively connected to the regulation cut-off.

Abstract: A dispenser includes a dispenser body which defines a flow passage, a valve assembly, and an actuator. The valve assembly is disposed in the flow passage and includes a first valve member and a second valve member. An actuator is coupled to the valve assembly. When the actuator is manipulated through a first range of motion, only the first of the two valve members is displaced, and when the actuator is manipulated through a second range of motion, both the first and second valve members are displaced in unison.

Abstract: A frost-proof valve includes a main valve. The main valve opens a fluid connection between an inflow opening and a discharge opening through a connecting channel in an open position and blocks the channel in a closed position. An actuating mechanism switches the main valve between the open position and the closed position. A drain drains the valve in the closed position and includes a bypass line connecting first and second channel sections.

Abstract: The present invention provides a faucet for tapping a liquid stored under pressure of a gas in a container that has less moving parts subject to wear or breakage, and has a housing made of multiple parts which can be disassembled so the faucet mechanism can be easily cleaned, repaired, or replaced. The faucet mechanism contains a piece of flexible tubing and an arrangement of a pinch roller valve mechanism that compresses the flexible tubing to shut off flow of liquid through the tubing. In one arrangement of the present invention, since the housing does not move and does not come in contact with the beverage being poured, the housing is made of a non-metallic material, such as a plastic or petroleum-based material, which is less expensive than the previous brass or stainless steel housing.

Abstract: The invention relates to an automatic precision pipetting device. The inventive device comprises at least two cylinder/piston-type pumping units (1, 2), the rods of which are rotated by means of a common motor unit (MP). Moreover, the pumping chamber of each of the pumping units (1, 2) is connected to a circuit comprising, successively, a conduit that opens into a container of rinsing liquid (RL), three successive solenoid valves (EV1, EV2, EV3) and a portion of circuit which connects the second solenoid valve (EV2) with the pipetting means (AP). The larger pumping chamber is connected in the part of the circuit that provides the connection between the two solenoid valves (EV1, EV2) while the second pumping chamber is connected to the above-mentioned portion of circuit by means of a connector, said portion of circuit comprising a solenoid valve (EV3) which is disposed between said connector and the aforementioned pipetting means.

Abstract: An air passageway opening/closing device provided with a plurality of sheet members provided with openings and passageway blocking parts located at the two sides of these openings, wherein the lengths in a direction of door movement of the openings differ by predetermined amounts, when an adjacent smaller sheet member moves in the direction of door movement by a predetermined amount, the smaller sheet member and the adjacent larger sheet member move together, the opening ranges of two air passageways are determined by a position of movement of an opening of the smallest sheet member to which a driving force is added, and the blocking ranges of two air passageways are determined by superposition of the passageway blocking parts of the plurality of sheet members in a stepwise offset state.

Abstract: The invention relates to a shut-off fitting comprising a housing which is connected to an adjacent pipeline in a pressure tight manner, the diameter of said pipeline defining a tubular passage in the housing. Said fitting also comprises at least one closing body which can be displaced between an open position and a closed position. The inventive shut-off fitting is characterized in that the at least one closing body can be displaced by an articulated mechanism, by means of an actuator which can be vertically displaced in relation to the flow direction, in such a way that it is arranged outside the tubular passage in its open position. The closing body has a contour which is adapted to the contour of the tubular passage, in the open position, and is located on the tubular passage in a radially sealing manner.

Abstract: A pressure relief valve for use on a dampener of a motorcycle suspension system is disclosed. The pressure relief valve includes a hollow body having an aperture that extends through the body, a valve cap that includes a recessed area with an entrance of a first diameter and a mid-portion of a second diameter, the second diameter being larger than the first diameter. Attached to the valve cap is a connecting shaft that is surrounded by a spring that urges the valve cap together with the connecting shaft from a second position where a pair of seals are formed, one a seal is formed between the valve cap and the hollow body and the other seal between the connecting shaft and the aperture in the hollow body, and to a first position where both seals are opened, so that when the valve cap is in the first position the enlarged portion of the connecting shaft creates a flow-path into the aperture through the hollow body.

Abstract: Certain embodiments of a fluid control valve include one or more ceramic components that operate substantially free of tensile stress concentrations along the control surfaces. In some embodiments, a fluid control valve includes a ceramic plug having a set of longitudinal grooves milled in the cylindrical surface of the plug to define control surfaces. The plug is disposed in an internal longitudinal cavity of the valve body such that the fluid flows over the plug's control surfaces in a direction substantially parallel to the control surfaces. The ceramic plug and other ceramic components may be manufactured using relatively simple machining techniques to reduce the overall production costs.

Abstract: A connection arrangement for transferring gas from a compressed gas cartridge, has a valve element configured to control the release of gas from the cartridge; a male outlet which is integral with the valve element; a male inlet of a gas receiver for a tool that runs on compressed gas; and a connector receiving and connecting the male inlet and outlet. The connector is a tubular housing having a through hole extending from one end to the other. An inner wall of the housing contacts side surfaces of the male outlet and inlet in a sealing manner. The connector also has, in a middle region, transverse sealing surfaces that contact the end faces of the male outlet and inlet. The diameter of the through hole in this middle region is the same as the inner diameters of the openings in the ends of the male inlet and outlet.

Abstract: A connection coupling for transferring gaseous and liquid fluids comprises a switch unit for actuating valves via a switch slide. The switch unit includes an eccentric shaft. The switch slide is coupled to an outer ring slide by at least one bolt.

Abstract: A gas cylinder dispensing valve having an internal flow path provided with a pressure regulator. An isolation valve is provided within the flow path between the pressure regulator and a gas inlet of the valve and a flow control valve is provided within the flow path between the pressure regulator and a gas outlet to discharge the gas. Both isolation valve and the flow control valve can be manipulated by a single control knob which when set in an off position closes the isolation valve. The control knob can be rotated from the off position to select discrete, calibrated flow rates or an auxiliary position in which gas may be dispensed at a regulated pressure from an auxiliary outlet port.

Abstract: A pressure relief valve for use on a dampener of a motorcycle suspension system is disclosed. The pressure relief valve includes a hollow body having an aperture that extends through the body, a valve cap that includes a recessed area with an entrance of a first diameter and a mid-portion of a second diameter, the second diameter being larger than the first diameter. Attached to the valve cap is a connecting shaft that is surrounded by a spring that urges the valve cap together with the connecting shaft from a second position where a pair of seals are formed, one a seal is formed between the valve cap and the hollow body and the other seal between the connecting shaft and the aperture in the hollow body, and to a first position where both seals are opened, so that when the valve cap is in the first position the enlarged portion of the connecting shaft creates a flow-path into the aperture through the hollow body.

Abstract: A damper unit for an air circulation system. The damper unit includes an air flow opening, a damper vane for opening and closing the air flow opening, and a motor for moving the damper vane between the open and closed positions. The damper also includes at least two ports, each port being operable in an input and an output mode. When a control signal is received on one port, the signal is sent out on the other port, and vice versa. The ports can be identical in shape to receive the same shaped plug.

Abstract: An electrostatic microvalve has a partition dividing a first and a second valve chamber from each other and having a through duct extending through it, such through duct opening at a first and a second opening into the first and the second valve chamber. In the first valve chamber there is a valve member for the control of first duct opening.

Abstract: A method and apparatus for servicing a pressurized system is described. A purge fitting can be used to vent the pressurized system. Venting can release a gas, such as air, from the system. The pressurized system can be a climate control system (e.g., an air conditioning or refrigeration system), a brake system, a hydraulic system, or a service device for servicing a climate control system. The purge fitting allows air that may be trapped in the pressurized system to be vented by depressing a purge actuator, such as a purge button attached to the fitting. The air can be vented from an opening adjacent to the actuator or other orifice. By purging air directly from the system, the amount of air introduced into the system during servicing can be minimized. The invention also features a coupling member that can be compact in size.

Abstract: A solenoid fuel drain valve (2) comprising a valve body (4), having a drain hole (20) and an air inlet opening (22), a solenoid coil (10) and a piston, the drain hole (20) having a drain inlet (20) and a drain outlet (15); and the piston being arranged within the valve body (4) to be moveable between a closed condition, wherein the drain hole (20) and the air inlet opening (22) are sealed, and an open condition, wherein the drain hole (20) and the air inlet opening (22) are open, movement of the piston being controlled by the solenoid (10).

Abstract: A valve for a pressurized container includes a valve housing having a central bore and a port in the for connection of a nozzle. Preferably, the valve has a unidirectional stepped valve housing. In the housing is a central bore that includes an upper portion, lower portion and a middle portion. The lower portion is narrower than the middle portion which in turn is narrower than the upper portion. The port is provided in the middle portion of said housing to facilitate connection of a nozzle to the valve. The valve has a t-stem with a lower end having a key-way and a cavity for receiving the upper portion of the valve seat. The valve seat provides the primary valve seal when the valve is closed. The upper portion of the valve seat has a geometry for engaging the t-stem to provide a locked assembly.

Abstract: Valve structures include a combination of spool valving and poppet valving. A spool function of the structure regulates the flow of a liquid, such as the flow of fuel to a diesel engine. A poppet function provides a low leakage in the valve in a closed or cut-off state. With this combination in a valve, spool clearance can be increased reducing the cost and precision machining/assembly of the components, because the poppet to seat closure provides the sealing function at cut-off. Included are an air-gap flux adjustment to adjust responsiveness to control current, and a force pre-load adjustment.

Abstract: A spigot valve, which on opening and closing of the spigot valve, selectively moves a plunger member to selectively open and close a closure valve at the outlet of a container to which a spigot valve is connected.

Abstract: A selector valve arrangement (4 or 6) primarily for a shower bath unit comprises a radially directed and angularly movable flow directing ported valve member (40 or 60) within a valve chamber (41 or 61) having ports (45-48 or 63-65) with which porting (44 or 66) of the valve member (40 or 60) selectively communicates on appropriate rotational positioning of the valve member (40 or 60). The valve member (40 or 60) receives fluid (usually water) for distribution through a selected port or ports (45-48 or 63-65) from an on/off fluid flow control inlet valve (43 or 30). In one arrangement a spindle (42) for rotating the valve member (40) is also axially operable and releasably lockable (49, 50) for operating the on/off flow valve (43).

Abstract: A valve device for a pressurised gas cylinder comprising a connector to be connected to a gas outlet orifice of a gas cylinder. A handwheel controls closing a gate valve or opening the gate valve to release gas from the cylinder. The output flow of gas released from the cylinder can be set.

Abstract: An electrostatic microvalve has a partition dividing a first and a second valve chamber from each other and having a through duct extending through it, such through duct opening at a first and a second opening into the first and the second valve chamber. In the first valve chamber there is a valve member for the control of first duct opening.

Abstract: The solenoid valve comprises a duct having an inlet opening and an outlet opening through which the fluid can pass substantially without changing direction, a valve seat within the duct, a closure member movable between a closure position and a fully-open position, and electromagnetic means for acting on the closure member in order to move it to any position between the closure position and the open position in dependence on an electrical control quantity. The electromagnet means comprise a core of ferromagnetic material, fixed firmly to the closure member and movable substantially along the same axis as the fluid, and a solenoid for generating a force on the ferromagnetic core along the same axis. A second closure member, movable along the same axis, may be provided in order to provide a solenoid valve with a double seal. The solenoid valve described is less bulky and expensive than known solenoid valves because it does not require a metal housing body.

Abstract: An improved fluid control valve includes a valve body with an inlet and an outlet. A sealing member is connected to the valve body conformed to seal the inlet and form a pressure chamber. A push rod is connected to the sealing member and a sleeve is provided which encompasses the push rod. A piston, forming an equalization chamber, is connected to the sleeve and to the push rod so that when the piston moves in one direction the sealing member is moved in the opposite direction until camover when both move in the same direction.

Abstract: A valve unit for controlling the delivery of a combustible gas through a gas path comprises a first valve seat in the gas path and a first closure means associated with the seat, a first actuator means for the control of the closure means for opening and closing of the valve seat and also motor means for the operating control of the first actuator means. The unit further comprises a second electromagnetic actuator means interposed between the closure means and the first actuator means to urge the closure means so as to close the valve seat, independently of the operating position of the first actuator means, when a predetermined condition occurs which requires the interception of the valve seat.

Abstract: A method and apparatus for servicing a pressurized system is described. A purge fitting can be used to vent the pressurized system. Venting can release a gas, such as air, from the system. The pressurized system can be a climate control system (e.g., an air conditioning or refrigeration system), a brake system, a hydraulic system, or a service device for servicing a climate control system. The purge fitting allows air that may be trapped in the pressurized system to be vented by depressing a purge actuator, such as a purge button attached to the fitting. The air can be vented from an opening adjacent to the actuator or other orifice. By purging air directly from the system, the amount of air introduced into the system during servicing can be minimized. The invention also features a coupling member that can be compact in size.

Abstract: Bi-directional pilot type electromagnetic flow valves are capable of preventing reverse flow while utilizing the advantageous properties of pilot type electromagnetic valves. Bi-directional pilot type electromagnetic flow valves may include two pilot type electromagnetic flow valves that are connected in series, but disposed in opposite operational directions. Preferably, one of the pilot type electromagnetic flow valves acts as an anti-reverse flow valve. Therefore, the two-way piping can be switch between a state preventing reverse flow and a state permitting reverse flow. Moreover, a relatively small solenoid coil can be utilized to drive the pilot type electromagnetic valves.

Abstract: A magnetically actuated valve system for controlling fluid flow through a first conduit and a second conduit. A first sealing structure associated with the first conduit is moveable in response to a magnetic force to an open position and spring biased toward a closed position. The closed position prevents fluid flow through the first conduit. A second sealing structure associated with the second conduit is moveable in response to a magnetic force in a second direction, substantially opposite to the first direction, to an open position and biased toward a closed position. The closed position prevents fluid flow through the second conduit. A magnetic actuator assembly is constructed and arranged to actuate the first and second sealing assemblies substantially simultaneously by moving the first and second sealing structures in the first and second directions, respectively.

Abstract: A reversible pneumatic motor assembly allows forward, reversing and throttling of a pneumatic motor by manipulation of a single lever with one hand. A reversing valve assembly of the motor assembly includes a tilt valve disposed in an inlet passage having a valve seat for receiving the valve to block the inlet passage. Forward and reverse passages extend from the valve assembly to the motor for driving the motor in forward and reverse directions. A shuttle connected to the lever can be moved transversely of the motor assembly.

Abstract: A filling spout having an adjustable flow rate and comprising a valve body receiving a valve member extending facing a valve seat, and a flow-rate adjustment member disposed upstream from the valve member and extending in register with a constriction in the valve body, the valve member and the flow-rate adjustment member being connected to a single actuator device via means allowing limited axial movement by enabling the adjustment member and the valve member to move axially relative to each other to a limited extent.

Abstract: A dual pendulum valve assembly including a housing having an interior space and first and second openings through which fluid can enter and exit the interior space; valve seats disposed in the interior space around the edges of the openings; and first and second pendulum valves for opening and closing, respectively, the first and second openings. Each pendulum valve is independently movable and includes a valve body mounted relative to the housing so that the valve body is movable between a completely opened position wherein fluid is allowed to pass through its respective opening and a completely closed position wherein the valve body seals the opening so that fluid can not pass therethrough.

Abstract: A throttle gate valve (10) including an upright, generally rectangular valve housing (12), in which is positioned a linearly movable gate valve (32) for closing off a thru-opening (15) formed in the lower part of housing (12). A pneumatic actuator assembly (14) is provided for moving the gate valve between its opened and closed positions. A throttle vane assembly compartment (16) forms the lower side of valve housing (12) and frames thru-opening (15), and includes a set of throttle vanes (18) rotatably positioned within thru-opening (15), and a drive actuator compartment (20) and motor (21) for controlling the position of throttle vanes (18). A drive actuator (51) is provided for rotating vanes (18) and is sealed by a bellows shield (70) at the point where the drive actuator extends into the interior of the housing.

Abstract: A valve includes a valve body having an upstream bore, a downstream bore, a fluid flow chamber and a valve seat useful for sealing the fluid flow chamber from the downstream bore. The valve also includes a valve stem, a bonnet connected to the valve body and adapted to receive the valve stem therethrough, and a plurality of sealing assemblies operably connected to the valve stem.

Abstract: Several downhole flow control devices are disclosed which are meterable and are also capable of shutting of a particular zone in a well. The several embodiments include a multiple valve body, a toroidal inflatable valve, and a series of related choke systems. The downhole flow control choke mechanisms each include a downhole electronics package to provide programming or decision making capacity as well as motor actuation systems. Each choke mechanism also includes a system whereby the device can be converted to manual operation and actuated by a conventional shifting tool.

Abstract: A gas-valve assembly has a housing having an inlet port, an outlet port, and a passage extending between the ports and defining an axis, a valve plug rotatable about the axis in the housing in the passage between a closed end position blocking flow between the ports and an open end position permitting flow between the ports, and a control knob rotatable on the housing and angularly coupled to the valve plug. Structure engaged between the knob and the housing prevents the knob from moving axially relative to the housing while permitting rotation of the knob about the axis relative to the housing. A safety valve in the housing has a valve body displaceable axially between a closed position blocking flow through the passage and an open position permitting flow through the passage.

Abstract: The invention refers to an actuating device for a double seat valve with cleanable seat, provided with two individually moveable closure members, which can be brought, additional to the open position, independent from each other, to a partial open position, wherein it shall be secured that the partial stroke movement to be carried out during the seat cleansing of the dependently actuated closure member is possible with relatively low pressures of the pressure medium, without the necessity to take pressure compensation measures at the respective closure member or for the increase of the diameter of the actuating piston. Furthermore it shall be possible, if required, to effect also the opening movement of the double seat valve with the conditions named above.