Abstract: Disclosed is a slit valve gate. The slit valve gate includes a base portion configured to couple to a slit valve actuator. The slit valve gate further includes a seal portion coupled to the base portion. The seal portion is configured to create an airtight seal between the slit valve gate and a sealing surface of a slit valve opening. The slit valve gate further includes a clamp portion coupled to the base portion. The clamp portion retains the seal portion at least partially between the clamp portion and the base portion.

Abstract: A connecting fitting is disposed on an upper face of a valve plate and is fixed to the connecting shaft. A first close-contact mechanism portion is formed at a portion where the connecting fitting and the connecting shaft are in contact with each other, a second close-contact mechanism portion is formed at a portion where the connecting fitting and the valve plate are in contact with each other, and a third close-contact mechanism portion is formed at a portion where the lower end of the valve plate and the lower end of the connecting shaft are in contact with each other. By bringing the valve plate and the connecting shaft toward each other with the close-contact mechanism portions of three vertical positions, a hole front face of a connection hole and a shaft front face of a connecting shaft are brought into close contact with each other.

Abstract: An injector is described for injecting a fluid, in particular a fuel, comprising a solenoid actuator for operating a closing element, which releases and closes a through opening, the solenoid actuator including an armature which is connected to the closing element, an internal pole and an external magnetic circuit component, and the magnetic circuit component is a rolled magnetic sleeve made from a strip material.

Abstract: The present disclosure relates to systems, apparatuses, and methods for assembling cartridges for aerosol delivery devices. The cartridges may be assembled by coupling a base of the cartridge to a carriage that is transported via a track. The track transports the carriages between various substations at which one or more parts are added to the base. The carriage may be lifted from the track by a lifter mechanism at each substation in order to perform assembly operations on the base. An inspection system may inspect the cartridges at various stages of completion at or between the various substations.

Abstract: Described herein are pipette driven well plates for nano-liter droplet storage and methods of using same. Embodiments may include an inlet, an outlet, a bypass channel, and a fluidic trap containing a valve covered by a removable covering, in which the fluid enters the fluidic trap when the removable covering is removed. The fluid enters either the fluidic trap or the bypass channel, depending on which of the fluidic trap or bypass channel has the lower hydrodynamic resistance. Embodiments may be used by closing the valve, introducing a first fluid to fill the fluidic trap and partially fill a bypass channel, opening the valve, removing the first fluid surrounding the valve, and introducing a second fluid into the fluidic trap, in which the introducing results in a mixture of the first and second fluids.

Abstract: In a throttle body for reducing the fluid pressure, particularly at a control valve, preferably for arranging in a process fluid line, of a process plant, such as a chemical plant, particularly a petrochemical plant, a power plant, a brewery or the like, with a plurality of channels extending from an upstream channel inlet to a downstream channel outlet, it is foreseen that an at least section-wise curved course of at least one of the plurality of channels between the channel inlet and the channel outlet deviates from a two-dimensional extension.

Abstract: A method for producing a pneumatically actuatable microfluidic analysis cartridge includes closing a joining side of a fluidic part of the analysis cartridge with a first fluid-tight elastic membrane and/or closing a joining side of a pneumatic part of the analysis cartridge with a second membrane. The fluidic part is configured to perform fluidic basic operations of a biochemical analysis process, and the pneumatic part is configured to control the basic operations using air pressure. The joining side of the fluidic part and the joining side of the pneumatic part are aligned, and the fluidic part and the pneumatic part are connected to form the analysis cartridge.

Abstract: Fabrication method of microfluidic devices consisting of a sheet (1) which is 200 micrometer thick or less and a rigid part (3), both made of thermoplastic polymeric material includes degasification of a polymeric sheet of thermoplastic material (1), an auxiliary rigid part (2), and a polymeric rigid part of thermoplastic material (3). A temporary bonding procedure, of the degassed thermoplastic polymeric sheet (1) to a degassed auxiliary rigid part (2), is conducted producing a sheet-auxiliary part set (4). A permanent bonding procedure bonds the thermoplastic polymeric sheet (1) of the sheet-auxiliary part set (4) obtained in the previous temporary bonding stage, to the thermoplastic polymeric rigid part (3) which was initially degassed. The auxiliary rigid part (2) of the thermoplastic polymeric sheet (1) permanently bonded to the thermoplastic rigid part (3), is detached to produce a final part which is completely polymeric (5).

Abstract: There is provided a method of producing a fluid channel device including laminating a plurality of polyimide films including at least one polyimide film having a port and at least one polyimide film having a channel, the polyimide films including at least one thermoplastic polyimide film; and adhering a plurality of the polyimide films by applying heat such that the ports are communicated with the channels. There is also provided the flow channel device produced by the method.

Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a memory cell and a select gate transistor formed on a semiconductor substrate. The memory cell includes a first gate insulating film, a first charge storage layer, a first intergate insulating film, and a first control gate. The first gate insulating film, the first charge storage layer, the first intergate insulating film, and the first control gate are formed on the semiconductor substrate in order. The select gate transistor includes a second gate insulating film, a first gate electrode, a second intergate insulating film, and a second control gate. The second gate insulating film, the first gate electrode, the second intergate insulating film, and the second control gate are formed on the semiconductor substrate in order. The second intergate insulating film different first and second thicknesses.

Abstract: A ram-type blowout preventer including an operating piston assembly isolated from wellbore pressure effects is provided. In one embodiment, a blowout preventer includes piston coupled to a ram by a connecting rod, and the connecting rod is inserted into a recess in the ram. A pressure-isolating seal may be provided in the recess between the connecting rod and the ram to isolate the end of the connecting rod within the recess from wellbore pressure in the blowout preventer. Additional systems, devices, and methods are also disclosed.

Abstract: An irrigation valve has a valve body with an inlet passage, an outlet passage, a valve seat intermediate the inlet passage and the outlet passage and a control chamber exit or bypass passage terminating in a surface that defines a portion of the outlet passage, the valve body including at least one of a recess and a rib for hindering clogging of the bypass passage. Related methods for hindering clogging of the control chamber or exit bypass passage are also disclosed.

Abstract: A fluid flow resistance assembly includes a fluid pathway. A width of the fluid pathway orthogonal to a flow of fluid through the fluid pathway varies along its length. Positioning of one or more ports at different locations over the fluid pathway at different locations controls a flow rate of fluid.

Abstract: Methods are presented that provide a thin, biocompatible, high-strength, composite material that is suitable for use in prosthetic valves. The composite material maintains flexibility in high-cycle flexural applications, making it particularly applicable to prosthetic valve leaflets. The composite material includes more than one porous expanded fluoropolymer layer and an elastomer present in the pores of the porous expanded fluoropolymer.

Abstract: A multi-layer one-way valve (100) includes: a first layer (10) having at least one first opening (12) formed therein; a second layer (20) having at least one second opening (22) formed therein; and, a third layer (30). The first and second layers are joined together such that at least one first channel (14) is defined therebetween, and the second and third layers are joined together such that at least one second channel (24) is defined therebetween. Additionally, an amount of flow-able liquid is deposited in the first channel between the first and second openings. Suitably, the valve selectively opens to permit gas flow through the first and second channels in response to a pressure differential, the rate of gas flow through the valve is exponentially proportional to the pressure differential.

Abstract: A valve assembly has a valve body, a lower bushing, a valve seat, a lower stem, a disc, and an upper stem. The valve body defines a bi-directional flow path therethrough; wherein the valve body has an inner surface, two flange faces, and further defines an upper orifice and a hemispherical lower orifice along an axis perpendicular to the flow path. The lower bushing is housed in the lower orifice, and the lower bushing is configured to tilt within the lower orifice away from the axis. The lower bushing defines a bushing cavity. The valve seat has an outer surface configured to encapsulate the inner surface and the two flange faces of the valve body. The lower stem is housed in the bushing cavity, and the lower stem is configured for tilting away from and towards the axis perpendicular to the flow path. The disc has a seating surface on at outer circumference, defines a stem receptacle to house the lower stem, and the stem receptacle extends less than a diameter of the disc.

Abstract: In an electromagnetic control valve configured to cancel out forces acting on a valve body by differential pressure using a diaphragm, pressure tightness and durability of the diaphragm are improved. A needle-shaped projection is formed on a lower end of a piston section of a valve rod that is a drive shaft. An insertion hole is formed in the center of a diaphragm guide. The center of the diaphragm is stuck on the needle-shaped projection to make it pass through it. The needle-shaped projection is inserted into the insertion hole in the diaphragm guide. An end of the needle-shaped projection is spot-welded. The diaphragm is stuck with the needle-shaped projection to fix it to the valve rod without cutting a base fabric of the diagram. A needle-shaped projection may be formed on the diaphragm guide and an insertion hole may be formed in the valve rod.

Abstract: A valve diffuser (3) for a valve (1), wherein the valve diffuser (3) has a valve seat (8) to make contact with a valve body. The valve seat (8) has a bushing (10) for making contact with a valve body. The bushing is formed from a different reinforced material wherein the valve diffuser (3) and preferably stellite.

Abstract: The present invention is directed to pressure relief devices and to corresponding pressure relief assemblies that have improved vacuum resistance, improved fragmentation resistance, and/or improved burst control while maintaining low mass. The pressure relief device includes a substantially flat flange section and a domed section. The domed section may include a transitional line that defines a change in the shape of the domed section. The pressure relief device may also include a bracket for securing or aligning a domed section to a flange section. The pressure relief device may further include a stress distribution feature that is disposed transversely to a line of weakness in the domed section. The pressure relief assembly may include a fastener having a wire that is configured to break and release the pressure relief device when subject to a predetermined tensile load.

Abstract: A multipoint injector for a turbomachine according to which any risk of fuel coking is eliminated is disclosed. The multipoint fuel which is liable to stagnate inside the circuit thereof is cooled uniformly, due to the formation of continuous baffles which each communicate with at least one separate circulation channel and of which the peripheral baffles open out into a fuel admission chamber arranged in a zone diametrically opposing the circulation channels and which communicates with the injection nozzle for pilot fuel in order to achieve uniform supply and cooling of the injector.

Abstract: An apparatus such as for a solenoid valve assembly includes a substantially annular flux collector (12) that has a first arced portion (10) and at least one additional arced portion (14). The first arced portion and the at least one additional arced portion are cooperatively configured to interlock with one another to form the substantially annular flux collector. A method (200) of manufacturing a solenoid valve assembly using the annular flux collector is also provided.

Abstract: A solenoid actuated valve assembly includes a valve body (122) comprising a fluid inlet (132) and fluid outlet (134), a valve member (128) disposed within the valve body, wherein a position of the valve member controls a fluid flow between the fluid inlet and fluid outlet, and a fluid chamber (140) above the valve member, wherein the fluid chamber is fluidly isolated from the fluid inlet and outlet. The solenoid actuated valve assembly further includes a solenoid actuator coupled to the valve body comprising a solenoid plunger (102) proximate the fluid chamber, wherein a force multiplying ratio of a surface area of the valve member exposed to the fluid chamber to a surface area of the solenoid plunger exposed to the fluid chamber is at least 1.5:1.

Abstract: Exemplary embodiments are directed to systems and methods used to minimize force variation from a solenoid through an operating stroke. The systems and methods generate a near constant or substantially constant force solenoid assembly which can be used in a force driven device, such as, for example, a pressure regulator for accurately controlling pressure in a pressurized flow system. The systems and methods are based on an initial solenoid characterization and include an application of springs and placement of the solenoid within the system at a gap distance to minimize variation in force in the operating stroke of a commercially available solenoid.

Abstract: A ball valve has trunnions that comprise shaft portions and larger diameter bearing portions. The larger bearing portions ensure that bearing pressures will be low. Smaller shaft portions reduce material costs and minimize the overall size of the valves. Preferably the bearing portions are formed out of a different material than are the shaft portions. This allows the bearing portions to be formed out of a lower strength (and therefore lower cost) material. Conversely, it also allows the shaft portions to be formed out of a higher strength material to thereby minimize the size of the trunnion shafts without impacting the bearing size and cost. Additionally, each bearing portion is preferably a cylindrical sleeve and is preferably heat-shrunk around part of the shaft portion.

Abstract: A valve has trunnions that comprise shaft portions and larger diameter bearing portions. The larger bearing portions ensure that bearing pressures will be low. Smaller shaft portions reduce material costs and minimize the overall size of the valves. Preferably the bearing portions are formed out of a different material than are the shaft portions. This allows the bearing portions to be formed out of a lower strength (and therefore lower cost) material. Conversely, it also allows the shaft portions to be formed out of a higher strength material to thereby minimize the size of the trunnion shafts without impacting the bearing size and cost. Additionally, each bearing portion is preferably a cylindrical sleeve and is preferably heat-shrunk around part of the shaft portion.

Abstract: A heart valve assembly includes a heart valve, a self-expandable and collapsible stent, and a sealing member. The stent includes an inflow end and an outflow end and is configured to support the heart valve internally. The sealing member is connected to and extends circumferentially around the stent. The sealing member includes a plurality of radially outward extending protrusions comprising a fold of material of the sealing member.

Abstract: According to one embodiment, a cladding portion is integrally formed on a sliding-contact surface of a valve rod or a valve body, which serves as a movable member, wherein the cladding portion is formed by inducing a pulsed discharge between an electrode which is formed of a molded body consisting mainly of a metal and a treatment target portion of the valve rod or the valve body, so as to weld and deposit a material of the electrode on a surface of the treatment target portion. A surface layer is integrally formed on a sliding-contact surface of a bushing or a sleeve, which serves as a stationary member, wherein the surface layer is formed by forming a first coating film by surface-hardening heat treatment using a metallic cementation.

Abstract: A tube assembly for a solenoid operated cartridge valve includes an adapter having an axially extending central bore along a longitudinal axis of the tube assembly for receiving an armature; a plug axially aligned with the central bore of the adapter; a nonmagnetic tube having a central bore along the longitudinal axis and aligned with the central bore of the adapter, the tube having a pair of respective annular axially-facing end surfaces abutting the adapter and the plug, the end surfaces being obliquely angled with respect to the longitudinal axis; and filler material positioned between and joining the adapter and the tube, and the tube and the plug.

Abstract: A vehicle brake hydraulic pressure control apparatus includes a base body and a solenoid valve. The solenoid valve is attached to an attachment hole which opens on one surface of the base body. A plurality of press-fitting portions that are press-fitted to an inner peripheral surface of the attachment hole are provided on an outer peripheral surface of the solenoid valve at an interval in a hole axis direction. Contact lengths, in the hole axis direction, between the inner peripheral surface of the attachment hole and two of the press-fitting portions are different from each other.

Abstract: An embodiment is directed to pressure plate for attachment to an infusion pump, where the pressure plate includes a tubing support surface at least partially surrounded by a raised perimeter support. The pressure plate includes a plurality of guide structures extending from the raised perimeter support that define a passageway for an infusion pump tube. Additionally an attachable flow stop assembly is included that includes an attachable occlusion arch and an attachable flow stop arm. The attachable occlusion arch includes a plurality of tab structures that couple to the raised perimeter support. The occlusion arch further includes an aperture configured to surround an infusion pump tube threaded therethrough. The attachable flow stop arm is operatively coupled to the raised perimeter support adjacent the attachable occlusion arch in a spring-biased fashion such that the aperture in the occlusion arch may be selectively occluded by the flow stop arm.

Abstract: Provided is a valve module for a stream selector that includes first and second pistons axially movable against a biasing force by fluid from an actuation passage acting on undersides of the respective pistons to move a valve head from a closed position to an open position where fluid flows from an inlet passage into a control chamber portion to an outlet passage. Thereby, the stream selector operates at significantly lower actuation air pressures, while providing a valve module that is backwards compatible.

Abstract: A hydraulic damper includes at least one valve assembly (9, 19) provided with rebound (11, 21) and compression (12, 22) valves and at least one resilient deflective disk covering flow channels (13, 23) of the valve assembly and preloaded by a spring (16, 26). The hydraulic damper includes means for clamping together the components of the at least one valve assembly and for preloading the spring. In order to increase the repeatability coefficient among dampers of the same production batch and render it independent on the geometrical tolerances of the valve assembly components, the means have a form of an adjustable nut assembly (17a, 27a) comprising a clamp nut (171, 271) and a shoulder sleeve (172, 272) fixed on the perimeter of the clamp nut. The clamp nut clamps together the components of the valve assembly and the shoulder sleeve preloads the spring with a predetermined force. method of assembling such a damper.

Abstract: Artificial heart valve structures and methods of their fabrication are disclosed. The heart valve structures may be fabricated from a biocompatible polymer and include one or more heart valve leaflet structures incorporated within a conduit. The valve structures may incorporate one or more conduit sinuses, as well as a gap between the lower margin of the valve leaflets and the interior of the conduit. In addition, the valve structures may include one or more valve sinuses created in a space between the valve leaflets and the conduit inner surface. Computational fluid dynamics and mechanical modeling may be used to design the valve leaflets with optimal characteristics. A heart valve structure may also incorporate a biodegradable component to which cells may adhere The incorporated cells may arise from patient cells migrating to the biodegradable component, or the component may be pre-seeded with cells prior to implantation in a patient.

Abstract: In accordance with an exemplary embodiment, a method for manufacturing a bypass valve of a turbine engine control system is described. The bypass valve includes a proportional valve and an integrator valve and the integrator valve includes an integrator spring assembly. The method includes forming the integrator spring assembly using an additive manufacturing technique. The integrator spring assembly comprises first and second end portions with a spring portion disposed between the first and second end portions. The first and second end portions and the spring portion are formed as an integral unit without welding or brazing using the additive manufacturing technique. The method further includes assembling the integrator spring assembly, the integrator valve, and the proportional valve into a complete bypass valve assembly.

Abstract: An exemplary valve seal assembly is provided that includes a valve body with one or more relief volumes that may extend circumferentially and positioned in or adjacent one or both an upper and lower member of the valve body. A compression seal positioned adjacent an opening of a relief volume and a seal that is provided primarily in a volume between the upper and lower members. In an uncompressed state, the compression seal is maintained adjacent the opening of the relief volume. In a compressed state when the valve seal assembly compressively engages a valve seat, the compression seal is compressed against the relief volume, and may be either fully or partially compressed into the relief volume. A relief volume primary angle may be provided at a desired angle, and a seal retention volume primary angle may be provided at a desired angle.

Abstract: A device for treating a patient suffering from obstructive sleep apnea or snoring can include an expiratory valve connected to a manifold. The expiratory valve can include a body portion including a feedback port configured to be connected to an air flow generator. The expiratory valve can include a plunger at least partially disposed in the body portion. The expiratory valve can include a pressurizing chamber positioned between an end of the plunger and an end of the expiratory valve. The pressurizing chamber can be configured to receive air from the air flow generator through the feedback port.

Abstract: A valve having a metal insert with a fluid passage formed in the metal insert. A composite valve body is disposed at least partially around the metal insert and having at least one port in fluid communication with the fluid passage with the metal insert. A valve member is partially disposed in the metal insert and operable to control the fluid flow through the fluid passage of the metal insert and parts of the valve body.

Abstract: A solenoid valve (200) is provided. The solenoid valve (200) comprises a fixed core (206) and a movable armature (420). The solenoid valve (200) further comprises a metallic tube bobbin (308) surrounding at least a portion of the fixed core (206) and/or the movable armature (420). A wire coil (203) is wrapped around the metallic tube bobbin (308).

Abstract: A method of making a replacement heart valve device whereby a fragment of biocompatible tissue material is treated and soaked in one or more alcohol solutions and a solution of glutaraldehyde. The dried biocompatible tissue material is folded and rehydrated in such a way that forms a two- or three-leaflet/cusp valve without affixing of separate cusps or leaflets or cutting slits into the biocompatible tissue material to form the cusps or leaflets. After the biocompatible tissue material is folded, it is affixed at one or more points on the outer surface to the inner cavity or a stent.

Abstract: A repeater system may control a pump by using a repeater and a user interface. An adhesive patch system may be used for affixing a pump or other object to a human body. Such an adhesive patch system may include two sets of adhesive members, each member including an adhesive material on at least one side so as to attach to the body. The members of the first set are spaced to allow the members of the second set to attach to the body in spaces provided between the members of the first set, and the members of the second set are spaced to allow members of the first set to detach from the body without detaching the members of the second set. Also, fill stations and base stations are provided for personal pump systems.

Abstract: A method for the production of a valve is provided comprising molding a valve body with a first mold, preloading the valve body with a second mold, molding a sealing portion in an open position onto the valve body, and releasing the preloaded valve body. The sealing portion enters a closed position when the preloaded valve body is released. When the valve is in use, the sealing portion opens when under a fluid pressure, and closes when the pressure is released.

Abstract: A kit for implanting a prosthetic vascular conduit includes a prosthetic vascular conduit for coupling to a prosthetic valve having an annular portion. The conduit includes a terminal collar member for receiving the valve. The kit further includes a holder including a shaft and a hub including a receiving portion configured for housing a prosthetic valve. The conduit is fitted on the holder so that at least a portion of the conduit wraps over the receiving portion of the hub. A sleeve member fitted onto the conduit in a position corresponding to the receiving portion of the hub, and a portion of the collar member is wrapped or folded over the sleeve member. The sleeve member is slidable away from the hub to unwrap the collar member such that it is disposed around the annular portion of a prosthetic valve.

Abstract: Apparatus and methods for removing valve cover components includes a torque transfer tool that mates with an extending portion of the valve cover assembly and has a multi-faceted segment to receive a torque-supplying wrench. A hydraulically-actuated wrench has a head with a multi-faceted portion that engages the corresponding multi-faceted segment of the torque transfer tool. The wrench's hydraulic cylinder rotates the wrench head upon actuation. The multifaceted segments can be splined. Also disclosed is a reaction tube against which the wrench can be braced prior to actuation of the cylinder.

Abstract: The present disclosure relates to a microvalve using surface tension, a microfluidic chip including same and a method for manufacturing same. More particularly, the present disclosure relates to a microvalve using surface tension, a microfluidic chip including same and a method for manufacturing same, wherein the microvalve can be manufactured through a simple process and the microvalve and a coaxial sample channel are not separated, and thus the microvalve may be easily installed not only in an existing quadrangular channel but also in the coaxial channel so as to control the flow and amount of a microfluid (sample).

Abstract: A MEMS check valve includes a supporting portion having a first perforation therethrough sized to permit fluid flow and includes a displaceable portion having a second perforation therethrough sized to permit fluid flow. The displaceable portion may be moveable relative to the supporting portion between a closed position inhibiting fluid flow through the valve and an open position permitting fluid flow through the valve. The first and second perforations are offset to inhibit fluid flow when the displaceable portion is in the first position, and fluid may flow through the first and second perforations when the displaceable portion is in the second position.

Abstract: The present invention is directed to a metering valve used in both conventional and bag-on-valve aerosol container applications that allows a high flow rate of especially viscous substances. The metering valve according to the present invention including a valve housing, a valve stem, and a spring or other biasing device that allows the valve stem to move relative to the valve housing. The valve stem serves as a metering chamber with a metering device in the form of a ball or disk without other mechanisms such as springs or mechanical parts within the valve stem. Radial bores and a seal near the bottom of the valve stem provide for dispensing of pre-determined quantities of product from an aerosol container pressurized with liquefied propellants or compressed gas. The bore shape and size can be selected to facilitate a high volume flow rate for highly viscous substances.

Abstract: A valved sheath introducer for venous cannulation, including a valve, sheath, handle and cap. The valve is configured to permit safe introduction and removal of medical instruments through the sheath introducer. The valve may have one or more anchoring members and a thickened central portion through which a slit is formed. The central portion may have one or more concave surfaces and the slit can be angled with respect to the top surface of the valve. The cap is attached to the handle, compressing a portion of the valve therebetween.

Abstract: Embodiments of the present disclosure are related to devices and techniques for para-valve sealing of an expandable stent-valve implanted using a catheter. In some embodiments, a stent-valve is provided which comprises a seal cuff containing material that swells when contacted by blood. A piercing tool may be included and used to permit a user to puncture the cuff prior to introduction into a patient's body. In some embodiments, the cuff has an integral tubular structure configured to withstand balloon expansion of the stent-valve during or after implantation.

Abstract: A method of making a metered dose valve or a component including the step of forming a coating on at least a portion of a surface of the valve or the component, wherein said coating comprises a particulate material selected from the group consisting of Magnesium Stearate, Calcium Stearate, Zinc Stearate, Aluminium Stearate, Stearic acid, Magnesium Palmitate, Calcium Palmitate, Zinc Palmitate or Aluminium Palmitate, Palmitic acid, and mixtures thereof.

Abstract: An inlet valve for a fluid pump includes a movably supported tappet for closing a fluid inlet opening and an actuator for moving the tappet, wherein the actuator and the tappet are formed separately from each other and can be coupled to one another by a coupling element for transmitting an actuator driving force to the tappet. An assembly method for such an inlet valve is also disclosed.