Abstract: The present application concerns a valve, and particularly position indicating assembly for use therewith. The position indicating assembly comprises a first end engageable with a valve member of the valve, an opposite second end displaceable with respect to a body of the valve in response to displacement of the first end, and an elongate bendable portion, extending between the first end and the second end, configured, upon movement of the valve member, to transmit forces operating along the elongate bendable portion, at least from said first end to said second end, so as to displace said second end, the elongate bendable portion being further configured for damping forces operating transversely thereto by reversibly bending.

Abstract: A diaphragm assembly for a pressure relief valve can include a disc guide that is configured to receive a portion of a disc holder, a bonnet adapter, and a diaphragm that is clamped at an outer edge between the disc guide and the bonnet adapter. The diaphragm assembly can be positioned between a bonnet of the pressure relief valve and a valve body of the pressure relief valve to convert the pressure relief valve to a backpressure-balanced pressure relief valve by counterbalancing a backpressure that acts upon the disc holder.

Abstract: A device and method for treating a wound of a patient with negative pressure is provided. The device comprises a heat-assisted pump system. The pump system can be powered in part by heat derived from the patient. The pump system may be configured to be highly planar, light weight, and portable. The pump system may comprise a Stirling engine or a thermal acoustic engine.

Abstract: A compression pump has a bladder that is supported during the compression stroke on the low-pressure side of the bladder, and that can have a compression cavity that is fully evacuated during each stroke. The compression pump can have a housing with an entrance section, a center section, and a crown section. The entrance and center sections define seats to receive bridge bearings (of bridges each having a rod and a bearing). A piston can have an inlet section, a middle section, and a head section. The inlet and middle sections define seats to receive groove bearings. The bridges and groove bearings structurally hold a support structure, which supports the bladder. The support structure can be a slide support that changes shape as the piston moves within the housing. The piston head can have a valve seat that the inlet valve head is received within when it is closed.

Abstract: Disclosed herein are various embodiments of a pump mechanism comprising a rigid structure having an open end and a closed end, a plunger disposed in the open end of the rigid structure, and a flexible, fluid-proof sheet of material attached to an inner wall of the rigid structure and bonded to the head of the plunger such as to form a fluid barrier between the interior of the rigid structure and the plunger. Movement of the plunger toward the closed end of the rigid structure causes a rolling corner to be formed between the head of the plunger and the rigid structure and a fluid contained within the pump chamber to be forced out of the pump chamber via a fluid port defined in the closed end of the rigid structure.

Abstract: A diaphragm for use in a pump includes a cover configured to contact fluid to pump the fluid and a backing disposed at least partially within the cover. The backing includes a flexible plate that extends outward relative to a core of the backing, the flexible plate configured to flex during reciprocation of the diaphragm. The cover is formed from a first polymer and the flexible plate is formed from a second polymer.

Abstract: An interface between an adapter push rod and a parking brake diaphragm seal includes an axial projection at one end of the push rod, a thread extending axially between a free end of the projection and a remainder of the push rod, and a washer having an approximately conical wall extending radially inwardly from an outer circumference of the washer towards a central mounting connection having a radial flange. A nut is threaded over the free end of the projection, and an opening in a hardened element is aligned axially with the projection to receive the projection. A circumferential groove defined in a side of the radial flange forms a boundary between the approximately conical wall and a remainder of the washer, and a portion of the diaphragm seal is pressed by the nut and the hardened element into the circumferential groove to produce a sealing bead.

Abstract: A fluid device including a fluid chamber which is designed for receiving a fluid and which is commonly delimited by a device housing and a bending-elastic membrane element. The membrane element with a peripheral edge section is fixed to the device housing in a fluid-tight manner and has a membrane working section which is framed by the peripheral edge section and which for the change of the volume of the fluid chamber can be elastically deflected by a piezoactuator. The membrane element consists of a rubber-elastic material, wherein the piezoactuator comprises a drive section which extends along the membrane working section, is embedded into the membrane element and is enveloped by the rubber-elastic material of the membrane element.

Abstract: A vehicle height adjustment system includes: an input housing part having a space in which working fluid is stored; an input piston part positioned in the input housing part, the input piston part configured to move along a lengthwise direction of the input housing part; a lead screw inserted into the input piston part, the lead screw configured to move in response to receiving external power; and a connection part fastening the input piston part with the lead screw.

Abstract: A foam dispenser includes a housing, a drive motor, and a foam pump. The foam pump includes a pump housing, and a molded multi-chamber diaphragm. The molded multi-chamber diaphragm includes a liquid pump diaphragm having a liquid pump stem and two or more air pump chambers each having an air pump stem. The length of the liquid pump stem is longer than the air pump stem. The foam pump further includes one or more outlet valves, a mixing chamber, an outlet for dispensing foam wherein the outlet is in fluid communication with the foam cartridge; and an actuator for sequentially actuating the liquid pump chamber and the two or more air pump chambers, wherein there is lost motion between the actuator and the liquid pump diaphragm.

Abstract: A pressure vacuum vent is disclosed which has a pressure plate having an opening, a diaphragm positioned on the pressure plate, a sealing ring for holding the diaphragm to the pressure plate, a sealing plate positioned on the diaphragm, a retaining ring for retaining the sealing ring, a screw having a cap having a vent opening, and a spring positioned between the cap and the sealing plate.

Abstract: Hydraulic cylinders and methods of fabricating hydraulic cylinders, including long-stroke rolling diaphragm cylinders with any stroke length. In some embodiments, the cylinders are manufactured to have a stroke length to bore diameter (“stroke-to-bore”) ratio optionally greater than 1:1. Various embodiments are suitable for use in a passive hydraulic body-powered wearable robot, for example.

Abstract: A spring brake actuator having a push rod plate and a diaphragm. A rim projects from the diaphragm for engaging a housing containing the push rod plate. A sidewall is connected to the rim, which is connected to a bottom surface, forming an outer diameter of the diaphragm. Flanges, perpendicular to the diaphragm, extend from the diaphragm forming an inner diameter for which the push rod plate is inserted into. An adhesive is placed between the diaphragm and the push rod plate, wherein the adhesive maintains an attachment and a seal between the diaphragm and the push rod plate keeping the diaphragm and the push rod plate in line with each other.

Abstract: A roll-diaphragm compressor and a roll-diaphragm compressors system, including methods for manufacturing and using same. The roll-diaphragm compressor includes a compressor body having a concave portion that defines a rounded interface wall and an apex portion adjacent to the concave portion that comprises an inlet and outlet port. The roll-diaphragm compressor also includes a flexible roll-diaphragm coupled to the compressor body about a compressor body edge and a compression chamber defined by the concave portion, apex portion and roll-diaphragm. The roll-diaphragm compressor further includes a piston head rigidly coupled to a central portion of the roll-diaphragm and configured to drive the roll-diaphragm to a first configuration where the roll-diaphragm engages the interface wall as part of a compression cycle.

Abstract: A turbocharger (1) includes a wastegate valve (30) supported on the turbine housing (8), and a pneumatic actuator (100) configured to actuate the wastegate valve (30). The pneumatic actuator (100) includes a housing (101) separated into compartments (104, 108) by a separating member (110, 112). The actuator (100) includes a piston (112) disposed in the housing (101) that defines at least a portion of the separating member (110, 112), a piston-biasing spring (120) disposed in the housing (101), a first in let (126) that is in fluid communication with the first compartment (104), the first inlet configured to be connected to a non-zero-pressure fluid source (8), and a second inlet (116) that is in fluid communication with the second compartment (108), the second inlet (116) configured to be connected to a non-zero-pressure fluid source (104).

Abstract: A diaphragm pump (1) which has in at least one pump head (2) a working or pump diaphragm (3) which, by means of a clamping zone (4) arranged at its outer circumference, is clamped between two housing parts (5, 6) of a pump housing and which, between itself and a pump head part (6), borders a working or delivery chamber (8) and which, in a central zone (10), surrounds a diaphragm armature (11) which, on a side facing away from the working or delivery chamber (8) of the at least one pump head (2), is connected to a reciprocating drive (12) which is provided for generating an oscillating stroke movement of the working or pump diaphragm (3).

Abstract: A simplified pump system may include a bellow having a suction valve, a stem, and a fluid lock wherein the product flow into and out of a pump chamber formed by the bellow and stem is controlled by the suction valve and fluid lock.

Abstract: A linear peristaltic pump with fingers includes a membrane positioned between the pumping fingers (250) and the tube. A part of the membrane against which the fingers (250) press, which part is called the track (212), is kept in permanent contact with the end of the fingers (250) throughout the duration of the pumping cycle, even in the absence of any tube. This material will be more rigid than the rubber conventionally used but, by virtue of the permanent contact, the track will not remain pressed against the tube but will, by contrast, be lifted by the finger (250). It will thus be possible to select a stronger material that will suffer less wear for the track. The precision of the pump will be guaranteed for longer and membrane changes that are painstaking and costly in terms of time and in terms of labor will be avoided.

Abstract: An air-driven dual diaphragm pump comprises a pump body with a first air passage leading to a first air cavity with a first diaphragm, a second air passage leading to a second air cavity with a second diaphragm, and a reciprocating shaft which connects the first and second diaphragms. A diaphragm installation tool for the dual diaphragm pump comprises a plate which fits atop the pump body. A groove in a surface of the plate opposite from and nonadjacent to the pump body extends from the location of the first air passage to the location of the second air passage. A hole located within the groove at the location of either the first air passage or the second air passage extends through the plate. Pressurized air entering the pump body is redirected by the groove and the hole to always enter the first air passage, rather than the second, thereby slowly filling the first air cavity and positioning the second diaphragm for installation.

Abstract: In a hydraulic fluid pump, in particular for a vehicle brake system, having a housing and a piston that is mounted in an axially movable manner in the housing in a piston chamber. A drive moves the piston and a sealing element seals off the piston chamber in the direction of the drive. The sealing element is designed as a diaphragm that extends through the piston chamber transversely with respect to the movement direction of the piston.

Abstract: A pump includes a pump body defining a fluid chamber and inlet and outlet ports in fluid communication with the fluid chamber, an inlet check valve connected to the inlet port, an outlet check valve connected to the outlet port, and a piston housing coupled to the pump body and defining a piston chamber. A piston assembly is disposed at least partially within the piston chamber and at least partially within the fluid chamber and includes a piston and a poppet connected to the piston in proximity to the pump body. In addition, the pump includes a gland disposed between a portion of the piston housing and the pump body. Further, the pump includes the poppet having a poppet head axially connected to a diaphragm coupled to a poppet flange. The poppet head is connected to the piston.

Abstract: A blow valve comprises at least one blow valve body, an environmentally controlled first receiving space constructed in the blow valve body and having at least one entry opening and at least one exit opening for receiving and conveying an operating gas, and a second receiving space constructed in the blow valve body for the guidance of a pressure distribution member such as, for example, a piston element. A sealing component prevents exchange of gas between the first receiving space and the second receiving space and is arranged between the first and second receiving spaces. The sealing component has a stationary part for fixing to the blow valve body and a movable part for changing the flow rate of the operating gas, wherein the setting member is surrounded in part by the sealing component and is coupled to the movable portion in order to move it.

Abstract: A flush valve diaphragm is provided. The diaphragm includes at least two by-passes orifices. Each by-pass orifice in the diaphragm has a by-pass associated therewith. Each by-pass having a passage therethrough, allows communication with the control chamber above the diaphragm with an inlet chamber below the diaphragm. The diaphragm also integrates the function of locating and providing sealing means to the flush valve system's aux valve mechanism.

Abstract: An apparatus can include a piston movably disposed within a pressure vessel and defines a first interior region and a second interior region. The piston has a first position in which the first interior contains a gas having a first pressure and has a volume greater than the second interior region, and a second position in which the second interior region contains a gas having a second pressure and has a volume greater than the first interior region. A seal member is attached to the piston and to the pressure vessel. The seal member has a first configuration in which at least a portion of the seal member is disposed at a first position when the piston is in its first position, and a second configuration in which the portion of the seal member is disposed at a second position when the piston is in its second position.

Abstract: A brake actuator having a plurality of actuator housing portions includes a diaphragm seal partially delimiting a parking brake de-actuation chamber and retained between adjacent portions of the housing. To produce brake actuation upon depressurization of the parking brake de-actuation chamber, a push rod extends into and out of a service brake actuation chamber upon release of fluid pressure from and supply of fluid pressure to the chamber. A clip or similar element receivable over the end section of the push rod is securable on the end section to compress the diaphragm seal axially relative to the push rod against a seat carried by the push rod while permitting a radial inner edge of the diaphragm seal to remain spaced from an outer surface of the end section.

Abstract: Water leakage and damage to the electric motor of a diaphragm type pressurized pump are avoided by providing the diaphragm with integral hollow cylinders which are inserted through ladder holes of piston head pushing chunks and deformed into sealing engagement with the pushing chunks and their corresponding wobble plates by screws extending through the cylinders and threadedly engaged within corresponding threaded holes of the wobble plates.

Abstract: A flush valve diaphragm of a flush valve includes a body having a segmented insert within a flexible body portion and a central passageway. The body further includes a peripheral sealing portion with the flexible body portion within the peripheral sealing portion. The peripheral sealing portion can include an integral filter, an exit chamber and a bypass arrangement, such that water flowing through the filter flows through the bypass arrangement. The integral filter version will retard clogging of the bypass arrangement. The segmented insert includes a plurality of trapezoidal members with outward protrusions. The plurality of trapezoidal members are connected to each other on their outermost edge by a runner.

Abstract: An air-operated diaphragm brake, more particularly a brake actuator assembly containing a diaphragm with a rib or ring design for centering and maintaining the location of a piston or push plate and for reducing debris build up in the brake actuator assembly. The diaphragm includes a projecting rim for engaging a housing containing a piston, a bottom wall having an interior surface for engaging the piston, a sidewall connecting the projecting rim with the bottom wall; and a plurality of ribs or a ring disposed on the interior surface of the bottom wall. The ribs or ring structure extends in a direction away from the intersection between the sidewall and the bottom wall, toward the center of the interior surface, and revolving around the center point of the interior surface.

Abstract: The invention relates to a system of bellows and co-acting part, including a co-acting part which comprises a stiff outer wall, and a bellows co-acting therewith which comprises a flexible wall of a predetermined shape and thickness, wherein the flexible wall of the bellows is movable along the stiff outer wall of the co-acting part, wherein the bellows includes at least two separately deformable flexible wall parts' which each co-act with a different part of the stiff outer wall of the co-acting part.

Abstract: An apparatus can include a piston movably disposed within a pressure vessel and defines a first interior region and a second interior region. The piston has a first position in which the first interior contains a gas having a first pressure and has a volume greater than the second interior region, and a second position in which the second interior region contains a gas having a second pressure and has a volume greater than the first interior region. A seal member is attached to the piston and to the pressure vessel. The seal member has a first configuration in which at least a portion of the seal member is disposed at a first position when the piston is in its first position, and a second configuration in which the portion of the seal member is disposed at a second position when the piston is in its second position.

Abstract: A diaphragm for use in a gas meter that includes an expansion section having a series of convolutions. During repeated use of the diaphragm, the expansion section flexes to allow the center section of the diaphragm and the attached diaphragm disk to move between a retracted position and extended position. The convolutions formed in the expansion section include a series of curved peaks and curved troughs joined by web sections. The multiple convolutions in the expansion section allows for more consistent and repeatable movement and volume displacement of the diaphragm between the extended and retracted positions. The action of the convolutions also contributes to extended life by eliminating wrinkling of the diaphragm material.

Abstract: A spring brake actuator having a push rod plate and a diaphragm is provided. A rim projects from the diaphragm for engaging a housing containing the push rod plate. A sidewall is connected to the rim, which is connected to a bottom surface, forming an outer diameter of the diaphragm. Flanges, perpendicular to the diaphragm, extend from the diaphragm forming an inner diameter for which the push rod plate is inserted into. An adhesive is placed between the diaphragm and the push rod plate, wherein the adhesive maintains an attachment and a seal between the diaphragm and the push rod plate keeping the diaphragm and the push rod plate in line with each other.

Abstract: In a motor generator pulley 122, a mechanical clutch 105 and a switching unit 132 are provided such that the mechanical clutch 105 is interposed between a first power transmission unit 104A and a second power transmission unit 104B and can transmit power even when an engine 102 serves as a drive element and a motor generator 103 serves as a drive element and when the motor generator 103 serves as the drive element and the engine 102 serves as the driven element, and that the switching unit 132 can switch, when at least one of the engine 102 and the motor generator 103 serves as a drive element, the mechanical clutch 105 so as to inhibit the engine 102 and the motor generator 103 from being connected to each other.

Abstract: A variable displacement piezo-electric pump which includes a pump housing having a side housing wall defining a pump chamber, an inlet line and an outlet line communicating with the pump chamber, a flexible pump diaphragm spanning the side housing wall in the pump chamber, a diaphragm-stroking mechanism such as a piezo-electric stack engaging the pump diaphragm and a diaphragm support provided between the diaphragm-stroking mechanism and the side housing wall of the pump housing.

Abstract: A brake actuator having a plurality of actuator housing portions includes a diaphragm seal partially delimiting a parking brake de-actuation chamber and retained between adjacent portions of the housing. To produce brake actuation upon depressurization of the parking brake de-actuation chamber, a push rod extends into and out of a service brake actuation chamber upon release of fluid pressure from and supply of fluid pressure to the chamber. A clip or similar element receivable over the end section of the push rod is securable on the end section to compress the diaphragm seal axially relative to the push rod against a seat carried by the push rod while permitting a radial inner edge of the diaphragm seal to remain spaced from an outer surface of the end section.

Abstract: A diaphragm pump for a pumped shower waste, comprises a diaphragm housing (12), a diaphragm (34) removably held in the diaphragm housing (12), an openable cover (16) on the diaphragm housing (12) for accessing the diaphragm (34), an electric motor (14), a connecting member (40) positioned in the diaphragm housing (12) and movable by the electric motor (14), and a non-screw-threaded twist and lock fastener (62) which releasably engages the diaphragm (34) with the connecting member (40). The diaphragm (34) can thus be disengaged and removed from the connecting member (40) without the use of a screwdriver.

Abstract: A pneumatic brake booster with a booster housing, which comprises a first and a second housing shell and is subdivided into a working chamber and a vacuum chamber by an axially movable wall to which a pneumatic differential pressure can be applied, with the movable wall being formed of a diaphragm plate and a diaphragm abutting thereon that includes a radially inward sealing bead and a radially outward sealing bead for sealing the two chambers and the radially outward sealing bead is compressible between the housing shells. To improve the compression of the radially outward sealing bead, the radially outward sealing bead has a circumferential, uniform rib structure.

Abstract: A diaphragm for a pressure-medium-actuated brake cylinder includes a radially outer fastening edge for fixing the diaphragm to the brake cylinder. At least one centering ring, which extends in an axial direction and is offset radially inward in relation to the fastening edge, is formed on the diaphragm. Via the centering ring, the diaphragm can be centered against a radially inner peripheral surface of a wall of the brake cylinder.

Abstract: Apparatus to seal a shaft to a diaphragm in a diaphragm actuator are disclosed. An example apparatus for use in a diaphragm actuator has a central aperture and an integral sealing protrusion disposed about a circumference of the central aperture. The sealing protrusion is configured to sealingly engage a shaft of the diaphragm actuator.

Abstract: A diaphragm for a diaphragm valve in particular for liquid fluids includes a backing membrane and a primary membrane which are supported by a central connection pin. Disposed axially between the backing membrane and the primary membrane is a reinforcing element.

Abstract: A piston-cylinder unit configured to provide a level adjustment function based on internal pressure includes a working cylinder, a piston rod, a working piston mounted on the piston rod, and fastening elements coupled to the piston rod and the working cylinder. Each fastening element is configured to attach to a chassis or a vehicle body. One of the fastening elements is mountable with freedom of axial movement relative to the piston rod or the working cylinder and includes a cylindrical bore and a chamber disposed between the cylindrical bore and an end surface of the piston rod or a journal of the working cylinder. The end surface of the piston rod or the journal includes a first effective pressure-actuated cross-sectional area approximately the same as a second effective pressure-actuated cross-sectional area of the piston rod. The first and the second cross-sectional areas are actuated by system pressure.

Abstract: The invention relates to a tandem pneumatic brake booster (1) for a vehicle. The objective is to prevent a blocking of a booster thrust rod (4) in the maximum travel position. The blocking appears following a sealed adhesion of a first plate skirt (12) on a seal (22) of the tandem booster. This seal blocks a vacuum in a first front chamber (5). To prevent this blocking, provision is made to crenelate a first lip (23) pressed against the pneumatic piston (3) of a seal. Merlons prevent a sealed adhesion of the plate skirt (12) over the whole seal (22). This absence of adhesion creates a leakage of air to the first front chamber (5) and allows a return to a rest position.

Abstract: In an actuator for a brake system or a method for making a brake actuator, an attachment mechanism for attaching a diaphragm to a piston includes a plurality of protrusions on one of the piston and diaphragm and a plurality of cavities on the other of the piston and diaphragm, each protrusion being insertable into a corresponding cavity to attach the diaphragm to the piston. Alternatively, a retaining ring is provided that need not be precisely made and yet can attach the diaphragm to the piston securely and sealingly.

Abstract: A piston 1 which is to be movably supported in a cylinder 11 of a pump 10 to be reciprocally driven is formed by a fluororesin so that it is not impaired by a corrosive liquid. A cylindrical outer peripheral portion 2 of the piston 1 has a thickness of 1 mm or less, and is flexible. The outer peripheral portion has a flange portion 7 in an open end portion via an approximately 180-degree folded-back portion 3. The flange portion 7 is attached to the cylinder 11. When the pump 10 is driven, the cylindrical outer peripheral portion 2 of the piston 1 smoothly rolls without producing deflections or bends in a gap between the outer peripheral face of a piston support member 15 and the inner peripheral face of the cylinder 11, while being in close contact with the two faces.

Abstract: A pneumatic servomotor (12) for power-assisted braking for a motor vehicle, which servomotor is of the type having a substantially cylindrical rigid casing (16) inside which a moving transverse partition (18) is movably mounted that has a peripheral skirt (28) which is made of sheet metal and which is covered, at least in the vicinity of its periphery (40), with a sealing diaphragm (30) made of an elastomer material and whose periphery (32) is fixed to the casing (16) in leaktight manner, said servomotor being characterized in that, in the vicinity of the periphery (40) of the skirt (28), the skirt is provided with a stamped annular recess (42) defining an internal groove (44) which serves to receive snugly a peripheral bead (46) which projects from the surface of the diaphragm (30) in order to fix the diaphragm (30) to the skirt (28) in leaktight manner.

Abstract: A diaphragm pump and method for making same, the pump having a diaphragm coupled to a wobble plate achieved using: a post (11) protruding from the wobble plate toward the diaphragm and at least partially surrounded by a collar (11a); and a pin (22) protruding from the diaphragm toward the wobble plate and having a recess (22a) for mating with the post (11) and also having an outer portion (22b) surrounding the recess (22a) and able to resiliently deform so as to squeeze through the collar (11a) when the pin (22) is pushed onto the post (11). The outer portion (22b) of the pin typically includes a locking feature (22c) for holding the pin (22) on the post (11). The pin (22) and the diaphragm are typically made from thermoplastic materials, with the pin (22) typically made from a harder material than the diaphragm.

Abstract: A vacuum unit for producing a stroke movement due to an applied vacuum. The vacuum unit includes a housing, a spring disposed in the housing, a diaphragm and a drive rod arranged on the diaphragm. The drive rod is positioned centrally on the diaphragm and is mounted in a longitudinal guide in the housing.

Abstract: A movable wall for separating an interior of a housing for a brake booster into a first chamber and a second chamber. The movable wall is characterized by a diaphragm, a backing plate and a hub member. The diaphragm has a peripheral bead secured to the housing and an axial bead located in a groove in a cylindrical body of the hub member. The groove has a front face that is separated from a rear face by an arcuate transition surface located between a bottom of the groove and the front face. The axial bead has a profile corresponding to the groove and an arcuate lip that extends from a rear surface. The lip is connected by a convolute to a radial section of the disc portion of the diaphragm while the backing plate has an axial opening surrounded by a radial surface that engages the front face of the groove. The axial bead engages the radial surface to urge the radial annular surface into engagement with the front face of the groove while sealing the front chamber from the rear chamber.

Abstract: A diaphragm pump including at least one diaphragm having an inner diaphragm surface, an outer diaphragm surface, and a projecting rim, the rim projecting from the inner diaphragm surface and having an inner circumferential surface and an outer circumferential surface, a hub positioned to lie within the inner circumferential surface of the projecting rim, a ring positioned around the outer circumferential surface of the projecting rim, where the hub and ring secure the projecting rim there between, and a reciprocating rod coupled to at least one of the hub and the ring.

Abstract: A control valve pressure actuator of the pressure-to-close type is provided with a housing in which an upper diaphragm casing thereof includes one or more air passage channels. Each of the air passage channels facilitates circulation of air above a diaphragm within the pressure actuator at all times, including when the diaphragm is in a fully open position. By permitting the circulation of air above the diaphragm even when in a fully open position, adjacent an inside surface of the top of the upper diaphragm casing, there is not a tendency for the diaphragm, biased toward the open position by springs, to stick to the inside surface of the top of the upper diaphragm casing.