Abstract: An artificial venous valve with unidirectional flow, for insertion into the human venous system, biocompatible with the receiver, comprises a hollow elongated support and a plate carried by and within the hollow elongated support and movable relative to the support between a position to permit flow of blood in one direction and a position in which to prevent flow of blood in an opposite direction through the support. The plate is movable to open and close over a pressure differential range on opposite sides of the plate of 1-50 mm Hg.

Abstract: An exhaust tube having an internal butterfly valve is coupled to the exhaust end of a conventional exhaust pipe extending from an internal combustion engine. The valve plate is mounted for swinging about an axis offset from the axis of the exhaust tube. The valve plate is spring-biased to a normal position substantially obstructing the exhaust tube. At high exhaust flow conditions, the valve plate is automatically swung to an open position in which flow through the exhaust tube is essentially unrestricted. Under back pressure conditions, the valve plate swings oppositely but still constitutes a substantial obstruction to exhaust flow. Consequently, the valve automatically opens at high flow conditions and automatically closes at low flow and back pressure conditions for more efficient operation of the internal combustion engine.

Abstract: An improved heart valve prosthesis arranged for permanent implantation to replace a defective natural heart valve, wherein the improved prosthesis device includes an annular body or ring designed to retain a pair of rotatable flat plate occluders. The structure of the present invention contains modifications which improve the flow dynamics therethrough, and reduce if not eliminate the formation of eddies or areas of stasis in and along the flow pattern. The annular ring is provided with oppositely disposed pairs of spherical segments which form pivot areas for the occluders, with the occluders being provided with concavities engageable with the spherical segments. Stops are provided for controlling the degree of arcuate travel or rotational skirt of motion. The abutment surfaces are arranged at positions spaced from the axis of rotation so as to improve the distribution of stresses created during closure.

Abstract: Heart valves are shown which utilize pivot arrangements that create prompt response to flow reversal and minimize resistance to blood flow in the open position. Illustrated are valves having a pair of identical leaflets that can assume an orientation in the fully open position near maximum blood flow rate that is precisely parallel to the centerline of the passageway. The ability of the leaflets to assume a precisely parallel or low energy position in the bloodstream reduces pressure drop across the valve and results in improved flow characteristics. A camming action adjacent the upstream edges of the leaflets in combination with interengagement at downstream locations on the valve body, spaced from the locations where the camming action with said upstream edges occurs, positively guide the leaflets to assure effective closing movement regardless of momentary deviations in the dynamics of the reverse flow of blood through the valve.

Abstract: A hermetically sealed electric motor compressor, comprising a hermetically sealed casing, a reciprocating compressor unit mounted within the casing and compressing a working fluid, the compressor unit having a first discharge passageway, a valve assembly mounted within the casing and opening and closing the first discharge passageway, the valve assembly having a second discharge passageway, a discharge port mounted to the second discharge passageway within the casing and including a muffler. The muffler defines a plurality of resonance chambers. The discharge port includes a base plate having a projection. The valve assembly includes a reed valve assembly including a reed valve and a valve backer mounted behind the reed valve.

Abstract: A prosthetic heart valve assembly of the type having a ring member and pivotable leaflet structure is provided. Each individual leaflet pivots on a pair of peripheral flat ear members that oscillate in mating respective spherical bearing recesses. These recesses are formed in separate bearing blocks that radially seatingly engage mid-wall holes in a rigid, cross-sectionally C-configured ring member. Retaining means holds the bearing blocks in association with the ring member. Edge portions of the ear members and adjacent leaflet edges wipe the recesses and adjacent bearing block surfaces, thereby to avoid blood stagnation and clotting.

Abstract: A fluid check valve of the two flapper variety which has replaceable seat flapper assembly. The assembly comprises a tubular ring having a seating area on the surface of one end and a reduced diameter portion on the other end. A pair of pin keepers are attached to opposite sides of the seat ring and the flappers are pivotably attached to a pin that passes through elongate holes in the keepers. The seat ring is a sliding fit in the bore of the valve body and abuts against an annular rib in the valve body bore. The reduced diameter portion of the seat ring extends through the annular rib. A retaining ring is attached to the reduced diameter portion by threaded engagement, bolts, or other means and tightened until it abuts against the other side of the annular rib thus holding the seat ring in tight assembly in the valve bore against the rib.

Abstract: A heart valve prosthesis having an annular valve housing or base and two leaflets supported for pivotable movement within the annular valve housing. Each valve leaflet possesses a composite curvature shape with pivoting hinges being purposely offset to the hydraulic force center of the annular valve housing to provide fast response of the leaflets to flow direction change. The hinge mechanism includes modified serpentine curved hinge recesses in the annular valve housing for receiving elongated leaflet ears allowing the leaflets to change their motion modes approaching the closed position to reduce leaflet-edge tangential velocity and impact of the minor edges against one another and the major edges against the housing seat upon closure. The composite curvature leaflets allow maximal central flow with consequent lower pressure drop during the open phase and minimal regurgitation during the closing phase.

Abstract: A flapper valve assembly for use in a flow conduit in a subterranean well, the assembly having a valve closure member pivotally connected to a floating hinge assembly that slidably engages a sleeve comprising the valve seat. A strut assembly comprising circumferentially spaced struts pivotally connected to the valve closure member away from the floating hinge member and pivotally connected to a spring guide surrounding the flow conduit is also provided, and is biased to force the valve closure member toward the closed position.

Abstract: Bi-leaflet heart valves have valve body contours and pivot arrangements that create quick valve response to flow reversal. Valve members or leaflets, which can have flat or curved inflow and outflow surfaces, are slidably and pivotally mounted in a heart valve body of contoured profile so they can be aligned precisely parallel to blood flow in the open position. The leaflets engage either projections extending radially inward from flat wall sections in the valve body sidewall or grooves in these flat wall sections. The shape and relationship of these interengaging surfaces, together with a centrally directed surge of backflowing blood which results from the strategic location of a pair of downstream recesses in the annular valve body, cooperate to provide prompt closing rotation of the leaflets from a parallel open orientation.

Abstract: An eccentric disk valve has return springs and indicators located outside of the valve housing. The valve disk is directly seated on the housing and the valve seat of the housing is described as a section of a right circular cone whose central axis is aligned with the axis of flow through the valve housing.

Abstract: A venting apparatus for a bubble contactor used to dissolve oxygen in water prior to introducing the water into a biological fluid bed reactor that, under aerobic conditions, removes potentially combustible contaminants from the water for removing fuel constituents from water. The venting apparatus includes a float-operated valve wherein the float senses the existence of a gas space in the upper part of the bubble contactor and is operable to open the valve to vent the gas space. Such a space is potentially capable of supporting a combustible mixture of oxygen and fuel constituents which could be ignited by a source, such as a static electric discharge. The valve remains closed under normal conditions when no significant gas space exists to prevent the needless waste of oxygen.

Abstract: A venting apparatus for bubble contactor employed in liquid treatment apparatus for removing fuel constituents from water. The liquid treatment apparatus includes an oxygenator for dissolving oxygen in the water prior to its introduction into a biological fluid bed reactor to support biological action in the reactor. The oxygenator includes a bubble contactor having a bubble contact chamber, and a venting apparatus for venting the bubble contactor when the bubble swarm in the contact chamber grows too large. The venting apparatus includes a lower valve assembly including a valve having a float mechanism for sensing unacceptable accumulations of gas bubbles in the lower part of the bubble contactor, below the desired lower level of the contact zone. The float also functions to open the valve to release the excess undissolved gas.

Abstract: A by-pass valve is affixed to the housing of a self-propelled submersible swimming pool cleaner. The pool cleaner includes a head having a suction chamber in which a propulsion mechanism is located for operation by water flow into the suction chamber. The head incorporates a by-pass inlet to the suction chamber downstream from the propulsion mechanism. A leaf spring biases the closure member over the by-pass inlet. The tension of the spring is overcome by the suction in the suction chamber when water flow into the chamber is blocked. Water flow is thus allowed into the suction chamber via the by-pass inlet. By placing the spring controlled by-pass inlet into the system flow stream between the cleaner propulsion mechanism and the system weir in the typical pool system, there is a small probability of the by-pass becoming blocked.

Abstract: A bypass damper for a forced air system comprising a freely pivotable damper blade with bent portions at the ends thereof and having an adjustment mechanism for adjusting the pressure set point of the damper.

Abstract: Bi-leaflet and single occluder heart valves have improved pivot arrangements that create quick valve response to flow reversal and minimize impact. Valve members or occluders, which have curved inflow and outflow surfaces, are slidably and pivotally mounted in a heart valve body and can be aligned precisely parallel to blood flow in the open position. Lugs on the valve members engage surfaces on projections extending radially inward from flat wall sections in the valve body sidewall, and the shape and relationship of these interengaging surfaces provide prompt initial rotation, low wear and reduced impact upon closing. Laterally directed ears engage the valve body arcuate sidewall and assist in defining the path of closing movement.

Abstract: A toggle linkage check valve includes a housing having an inlet and an outlet, and a valve assembly disposed within the housing. The valve assembly includes (i) a sealing plug adapted for movement between a first, closed position for preventing flow of liquid between the inlet and the outlet, and a second, open position for substantially permitting flow of liquid between the inlet and the outlet, and (ii) a spring assembly removably disposed within the valve assembly. The spring assembly contacts the sealing plug and biases the sealing plug towards the first, closed position. The spring assembly comprises a rod member and means for biasing the rod member toward the sealing plug. In the second, open position of the sealing plug, the rod member lies at an acute angle to a plane of the sealing plug.

Abstract: Bi-leaflet heart valves have improved flow characteristics in their open position as a result of employing valve bodies of elongated axial dimension. By elongating the axial dimension of valve bodies which have straight, smooth interior wall surfaces oriented parallel to the centerline through the valve and to the flow path of blood, and by employing a pair of occluders which have major surfaces that are rectilinear and can assume an orientation that is substantially parallel to the centerline in the open position, a streamlining of blood flow occurs. The pivot arrangements avoid the use of acute angular surface orientations and cause the occluders, although aligned substantially parallel to blood flow in the open position, to promptly pivot toward the closed position upon reversal of blood flow. This streamlining substantially reduces turbulence and results in low head loss, both significant advantages in bi-leaflet heart valve performance.

Abstract: Sewer check valve and cleanout apparatus including a valve body, substantially inverted-T in shape, said valve body provided with a horizontal conduit and an upright external riser; an internal riser receivable within the external riser; and a flapper. The horizontal conduit of the valve body is provided with opposing end hubs for attachment to existing sewer and drainage lines and is provided, on its upstream portion with an annular valve seat about the conduit. The flapper is pivotally attached to the lowermost end of the internal riser to sealingly engage the valve seat. The internal riser, with flapper, are readily accessible for maintenance or replacement by a simple retraction of the internal riser from the external riser. The internal riser is provided with a curved bore, cooperating with a curved bore in the external riser for directing cleanout cables downstream and away from the flapper valve.

Abstract: A backflow preventor which permits adjustment of the outflow direction is provided. A conduit provides fluid communication between the two valves of the backflow preventor. The conduit can be separated, e.g., by cutting along a groove, leaving annular flat regions. The annular flats are configured to engage with a coupler to provide leak-free connection between the separated portions of the conduit. The separated portions of the conduit can be rotated to adjust the outflow direction. Preferably, an infinite number of outflow directions are possible, all of which lie in a plane parallel to the inflow direction.

Abstract: A valve unit for a hermetic reciprocating compressor comprises a valve plate adapted to be attached to the end of a piston cylinder. A discharge passage is formed through the valve plate, and a valve assembly is mounted within a stepped recess formed in an outer side of the valve plate for opening and closing the discharge passage. The outlet end of the discharge passage is situated within the recess and is spaced inwardly from the outer side so that the length, and hence the volume, of the discharge passage is reduced. Hence, the amount of compressed gas remaining in the discharge passage at the end of a piston stroke is correspondingly reduced, so that a vacuum can be formed in the piston chamber more quickly as the piston is retracted.

Abstract: A head (10) for mounting a replaceable spin-on fuel filter element (12) for use in a vehicle fuel system, includes an inlet (18) and outlet (76). The inlet is connected in the head to a second chamber (24) through a first check valve (26). The first check valve enables flow only from the first chamber to the second chamber. The second chamber includes a manually actuated pump (28). The second chamber is connected to a fluid in-flow area (64) of the element through a second check valve (62). The second check valve enables flow only from the second chamber to the in-flow area. The first chamber is also connected to the in-flow area of the element through a third check valve (84). The third check valve enables flow only from the first chamber to the in-flow area of the element. To remove air from a newly installed element and to prime the fuel system of the vehicle, the manual pump is cycled.

Abstract: An internal combustion engine system having reduced high speed emissions comprising an exhaust driven supercharger having turbine pressure dependent control means for regulating turbine pressure and turbine speed to a substantially constant value to produce a decreasing compressor pressure profile with increasing engine speed and to reduce mass air flow through the engine during high speed operation, thereby reducing engine emissions and improving durability.

Abstract: In an oil field tubular assembly, a flapper valve permitting downward flow and blocking upward flow is closed by down-hole pressure. A pivotally mounted flapper is urged to the closed position by a spring force, which may be moderated approaching the open position to reduce flow resistance, and an offset valve inlet passage provides clearance for flapper opening and room for the pivotal mounting.

Abstract: A cardiac valve prosthesis comprising an annular body housing a closure member in the form of two cusps. The cusps open and close freely and rotate simultaneously around the body axis, checking the forward and reverse blood flows through the prosthesis to simulate the operation of the cardiac valve. To have the operation of the prosthesis resemble that of the natural valve, the lateral surface of at least one cusp is provided with a recess to produce a controlled blood backflow through the prosthesis by causing the blood flow through the prosthesis to swirl.

Abstract: The heart valve prosthesis has a generally annular base that has an annular body and diametrically opposite chordal segments having generally parallel flat surfaces. Each chordal segment has a pair of spherical recesses opening through the flat surface, the spherical recesses having ears of a pair of leaflets pivotally extending therein for movement between valve open and closed positions. For improving blood flow characteristics, each chordal segment has an upstream conical surface that is tapered generally radially inwardly in a downstream direction and a downstream conical surface that is tapered generally radially inwardly in an upstream direction. The conical surfaces intersect the flat surfaces.

Abstract: A discharge valve for a compressor includes a valve plate having a recessed portion formed around a discharge port with a valve seat. A channel having a raised bottom surface is formed at the recessed portion. A valve reed is positioned at the recessed portion, having a circular portion for engaging with the valve seat and a base portion supported on the raised bottom surface of the channel. A valve spring is resiliently mounted over the valve reed to hold the valve reed. The valve spring has an inwardly bent section for press-contacting with the valve reed and an outwardly bowed section with a bent tip, which is resiliently deformable for adapting to the opening movement of the valve reed.

Abstract: A bi-leaflet heart valve having pivot ears comprising frusto-conical segments, located substantially at a diametral edge of leaflet occluders of the valve. Pivots on adjacent edges of both occluders share a common recess in an annular body of the valve.

Abstract: A toggle linkage check valve includng a housing having an inlet and an outlet and a sealing plug disposed within the housing and adapted for movement between a first, closed position for preventing flow of liquid between the inlet and the outlet, and a second, open position for substantially permitting flow of liquid between the inlet and the outlet. The check valve includes a spring assembly removably disposed within the housing. The sealing plug is mounted upon the spring assembly. The spring assembly includes a rod member and a means for biasing the rod member toward the sealing plug. In the first position of the sealing plug, the rod member lies substantialy perpendicular to a plane of the sealing member across the inlet, and in the second position of the sealing plug, the rod member lies at an acute angle to the plane of the sealing member.

Abstract: A cardiac valve comprises a ring, one or more flaps, the pivoting axis of the latter including two balls partly extending into a ring cavity and a conical flap cavity. This arrangement improves the life of the valve by reducing wear, stresses, friction and facilitates the assembly thereof if the ring is constituted by two concentric members and if the ring cavity extends on either side of the inner member. The invention more particularly applies to artificial valves installed in the heart in place of defective natural valves.

Abstract: A flapper valve assembly when closed permits flow through in one direction and prevents flow in the opposite direction. When open, two way flow may occur and the flapper valve member is biased toward closed position, to sealingly engage an annular seat, by one or more springs in the wall of the flapper valve housing. This structure provides a greater closing force applied to the flapper valve through a tension member connected to the flapper valve hinge. Three forms of tension members are disclosed.

Abstract: A valved catheter is disclosed having an elongated, flexible tubular element extending along a central axis and a flow portion of a valve assembly which controls fluid flow in the tubular element. The element is adaptable for bidirectional flow of fluid between its proximal and its distal ends, with a bidirectional valve assembly coupled to the interior of the tubular element. The bidirectional assembly generally defines a control plane which intersects the central axis at an oblique angle. The assembly has an inflow portion and an outflow portion nominally disposed to lie in the control plane. The inflow portion includes an inflow vane positioned between the intersection of the control plane with the central axis and the distal end and which is adapted to be deflected out of the control plane toward the distal end in response to the establishment of a relatively high fluid pressure at the proximal end and a relatively lower fluid pressure at the distal end.

Abstract: An integrated induction system for providing fluids to the cylinders in an engine comprises a casing adapted for mounting on the engine. The casing has an air inlet and a plurality of fluid outlets. A plurality of air tubes are disposed within the casing so that air entering the air inlet flows through the air tubes and respective fluid outlets to the cylinders. A fuel injection assembly is mounted within the casing to inject fuel into the air exiting the air tubes adjacent each of the fluid outlets causing a mixture of air and fuel to enter the respective cylinders. Provision is made for venting the casing when the pressure therein reaches or exceeds a predetermined limit.

Abstract: A check valve assembly adapted for use in a fire protection system includes a housing defining an inlet, an outlet, a seat and a chamber. A clapper or valve element is mounted within the chamber for movement towards and away from the seat. A parallelogram linkage supports the clapper. A pair of draw bars extend diagonally between opposed links. Each draw bar defines a stop. A coil spring encircles the draw bars and engages the stops. Expansion of the coil spring forces the draw bars apart and resiliently biases the clapper or valve element against the valve seat.

Abstract: A casing shut-in valve system (74) having a flapper valve assembly (34) and a shift head assembly (76); the flapper valve assembly (34) having an upper body member (36), lower body member (38), flow sleeve (40), valve seat sleeve member (42), flapper (54), flapper hinge assembly (56), and a plurality of spring strut assemblies (58) disposed on opposite sides of the flapper hinge assembly; the shift head assembly (76) having key housing (134) with bit sub (144) rotatably mounted in bearing (152), a plurality of outwardly biased shift keys (80), and a load equalizer plate (138) at each end of the key housing; the shift head assembly (76) being adapted to selectively open or close the valve by engaging and moving the flow sleeve (40) between defined upper and lower positions, thereby controlling the movement of flapper (54) through an angle (128) of rotation that is less than 90 degrees, and preferably about 45 degrees.

Abstract: A wellhead stuffing box for a polished rod includes a body with an elongated opening extending through it to receive the polished rod. Packing in the body makes a sliding seal around the polished rod and a static seal against the interior of the body. Internal pushers are provided for compressing the packing with the required force for appropriate sealing, and the internal pushers cannot be changed without disassembling the body.

Abstract: Bi-leaflet heart valves have improved flow characteristics in their open position as a result of employing valve bodies of elongated axial dimension. By elongating the axial dimension of valve bodies which have straight, smooth interior wall surfaces oriented parallel to the centerline through the valve and to the flow path of blood, and by employing a pair of occluders which have major surfaces that are rectilinear and can assume an orientation that is substantially parallel to the centerline in the open position, a streamlining of blood flow occurs. The pivot arrangements avoid the use of acute angular surface orientations and cause the occluders, although aligned substantially parallel to blood flow in the open position, to promptly pivot toward the closed position upon reversal of blood flow. This streamlining substantially reduces turbulence and results in low head loss, both significant advantages in bi-leaflet heart valve performance.

Abstract: A unidirectional flow heart valve includes a passageway having an inlet side and an outlet side. A disk occluder is disposed within the passageway. The disk occluder has a closed position wherein the disk occluder occludes fluid flow through the passageway and an open position wherein the disk occluder permits fluid flow through the passageway. A fulcrum causes the disk occluder to pivot off center between the open and closed positions. An electromagnetic control mechanism forces the disk occluder to remain closed when energized until a predetermined net pressure is reached against the disk occluder. When the electromagnetic control mechanism is either selectively deenergized or the force on the occluder disk is greater than the holding force of the electromagnetic control mechanism, the disk occluder is released from the closed position to pivot on the fulcrum in response to fluid pressure.

Abstract: A subsurface safety valve has a resilient valve seat and an upwardly closing flapper plate whose sealing surfaces each have a match spherical radius of curvature. The sealing surface of the valve seat is a concave spherical segment of elastomer material and the sealing surface of the flapper plate is a convex spherical segment. The matching spherical surfaces are lapped together to provide a metal-to-metal seal along the interface between the nested convex and concave sealing surfaces. This permits angular displacement of the flapper plate relative to the valve seat without interrupting positive sealing engagement. The concave spherical seating surface of the resilient valve seat will tolerate a limited amount of misalignment of the flapper plate which may be caused by operation in low differential pressure, sandy well conditions.

Abstract: A backflow preventor with increased performance, and increased ease of installation is provided. The check valves are configured to assist in redirecting flow along the desired pathway, when they are in the open position. The pathway is designed so that the number of changes of flow direction of the average streamline flow is reduced, preferably being about 180.degree.. The check valves are configured to reduce or eliminate divergent flow around the edges of the valve disks. A check valve with a reduced hold-open pressure includes a biasing device, such as a spring, directly connected to a pivoting clapper at one end and to the valve body at the other end. No intervening pivoting links are used between the spring and the clapper. Preferably, the clapper is connected only by being pivoted to the valve body and by the spring connecting it to the valve body.

Abstract: A cantilever leaf spring (1) attached to a fixed frame or movable member of a gas isolator is acted on by a bias spring (2) and an additional similar, but not identical, bias spring (12).

Abstract: A closure element for use in circular ducts for controlling the flow of material in the duct. The element has a unique unitary shape which allows installation within the confines of the duct with minimum distortion of the duct cross-section when the valve is open. This results in a very low pressure drop through the valve. Because the closure element geometry is such that the element pivots from the duct wall solely within the confines of the duct, the valve is well suited as a check valve.

Abstract: Disclosed is a heart valve of the pivotal bi-leaflet or single occluder type having improved washing characteristics in the region of the support arrangement. The leaflets include cylindrical, or other circular cross-sectional, pivot enlargements at opposite sides of the leaflets, and the valve body includes a number of projections extending inward from its sidewall. The leaflets are mounted in the valve body such that the projections encircle the pivot enlargements at the opposing ends of the leaflets, thereby confining their movement to substantially pivotal rotation between open and closed positions. The projections are spaced from one another, with the region between adjacent projections defining channels through which blood can flow. Some blood flows through these channels both when the valve is in its open position and its closed position, thereby providing blood flow across the pivot enlargements and projections and, thus, minimizing stagnation in the region of the support arrangement.

Abstract: An improved heart valve prosthesis (20) suited for replacement of any of the four valves in the heart. The invention includes a generally annular orifice ring (22) having a fluid flow bore with a smooth inner wall (26) through which blood flows, controlled by two pivoted leaflet occluders (40), supported at the downstream edge of the orifice ring.The occluders are supported at the outboard edges of the orifice ring, overlapping the fluid flow bore and generally about each other to seal backflow and regulate flow in one direction only. Occluder travel is limited by bending moment resistance of the occluder hinge and lateral blood flow. Occluder hinges are unloaded at a point between fully opened and fully closed.The bearing surfaces between the occluder means and the annular orifice are wide enough to allow the valve to be constructed from materials of different hardnesses.

Abstract: A method and apparatus for improving mixing of fluids has at least two static mixing stages connected in series with a bypass valve connected in parallel across each but the last of the mixing units. The capacity of each downstream mixing unit should be such that its minimum flow requirements overlap the opening point for the check valve of the preceding mixing unit. Pressure drops exceeding predetermined limits cause the bypass valves to open allowing fluid flow therethrough thereby preventing further pressure drop through the mixing unit.

Abstract: A toggle linkage check valve including a housing having an inlet and an outlet and a sealing plug disposed within the housing and adapted for movement between a first, closed position for preventing flow of liquid between the inlet and the outlet, and a second, open position for substantially permitting flow of liquid between the inlet and the outlet. The check valve includes a spring assembly removably disposed within the housing. The sealing plug is mounted upon the spring assembly. The spring assembly includes a rod member and a means for biasing the rod member toward the sealing plug. In the first position of the sealing plug, the rod member lies substantially perpendicular to a plane of the sealing member across the inlet, and in the second position of the sealing plug, the rod member lies at an acute angle to the plane of the sealing member.

Abstract: A prosthetic heart valve of the type that includes an annular support ring and at least one valving member. The valving member includes a pair of rotational members and the annular support ring includes a pair of apertures that each support a releasable insert. The releasable inserts include axle members that have a predefined rotational contact surface and the rotational members include depressions having a predefined rotational support surface. The geometries of the rotational contact surface and rotational support surfaces are such that a substantial point contact of rotation exists when the two surfaces are rotationally engaged. The invention may be conversely practiced with the releasable inserts including a depression and the rotational members including axle members.

Abstract: A controlled valve with clack valve and a clack valve including a controlled valve, as well as an aircraft with a controlled valve of this type, are disclosed. The disclosed controlled valve has a clack valve on its surface. The controlled valve is used for the "fine" regulation of pressure or flow rate. The clack valve enables safety balancing of pressure. The incorporation of the clack valve in the controlled valve or of the controlled valve in the clack valve makes it possible to have only one opening in the partition surface and, thus, to reduce the weight and cost while increasing security. The disclosed device can be applied to any device for the regulation of pressure and/or flow rate between a chamber and the exterior or between two chambers having a safety balancing device. The disclosure can be applied notably in aeronautical construction, the construction of petroleum refineries, of fluid distribution devices and of chemical reactors.

Abstract: A differential loading fluid check valve, including a unitized valve body having a single service port in its sidewall for selective access to the interior chamber of the check valve. Check valve subassemblies are installed and removed through the service port for valve assembly and service. The same valve body can be configured for either single or double check valve operation by adding or removing check valve subassemblies. Each check valve subassembly includes a base with an aperture, a pivotally mounted clapper, and an overlying pivotally mounted cam arm, spring biased against the movable end of the clapper. An arcuate surface on the cam arm is engaged by the clapper as it moves from a closed position to an open position, providing a beneficial differential reduction in the pressure drop, or loading, through the check valve.

Abstract: An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.