Abstract: A pressure regulating valve for an inkjet printhead. The valve includes: a fluid flow path defined between a valve inlet and a valve outlet; an orifice positioned in the flow path; a movable valve member configured for regulating a fluid flow rate through the orifice; a regulator chamber having the valve outlet and including a diaphragm operatively connected to the valve member, such that movement of the diaphragm moves the valve member relative to the orifice; and a biasing mechanism for resiliently biasing the diaphragm away from the orifice. An outer surface of the valve member is non-linearly flared away from the diaphragm.

Abstract: Hydraulic valves for dampening pressure spikes and associated methods are disclosed herein. In one embodiment, a hydraulic valve for dampening pressure spikes includes: a spool configured to move axially inside the hydraulic valve; and a sleeve configured to at least partially house the spool. A location of the spool with respect to the sleeve may determine a flow of a working fluid through the hydraulic valve. A viscous damper is at least partially housed inside an opening in the spool, and a viscous friction between the viscous damper and the opening in the spool slows a motion of the spool.

Abstract: An example valve includes: an external component having a longitudinal cavity therein, wherein the external component comprises a first annular groove disposed on an interior peripheral surface of the external component, and wherein the first annular groove is bounded by two annular surfaces; an internal component disposed, at least partially, in the longitudinal cavity of the external component, wherein the internal component comprises a second annular groove disposed on an exterior peripheral surface of the internal component, wherein the second annular groove is bounded by two respective annular surfaces, wherein the second annular groove is aligned with the first annular groove, such that the first annular groove and the second annular groove form an annular space therebetween; and a retention O-ring disposed in the annular space formed between the first annular groove and the second annular groove.

Abstract: A fluid valve has a valve plug configured as follows. In order to control a flow rate of a fluid between a first pressure chamber and a second pressure chamber, the valve plug is provided so as to be openable and closable in accordance with a difference between forces generated by pressures in the pressure chambers and resilience of an elastic member. The fluid valve includes an opening motion promoting portion. The opening motion promoting portion promotes an increase in degree of opening of the valve plug after the valve plug has been opened.

Abstract: A dual stage pressure relief valve for relieving pressure. The pressure relief valve includes a main body, a poppet bulb, a pilot piston, and a poppet cap. The main body defines a main channel that extends from a first opening to a second opening. The poppet bulb defines a first flow channel being in fluid communication with the main channel. The pilot piston defines a reset channel in fluid communication with the first flow channel of the poppet bulb. The cap channel has a diameter that is greater than a diameter of the reset channel. The poppet cap defines a cap channel in fluid communication with the reset channel of the pilot piston and with a pressure cavity defined by the poppet cap and an end of the main body.

Abstract: An example valve includes: an external component having a longitudinal cavity therein, wherein the external component comprises a first annular groove disposed on an interior peripheral surface of the external component, and wherein the first annular groove is bounded by two annular surfaces; an internal component disposed, at least partially, in the longitudinal cavity of the external component, wherein the internal component comprises a second annular groove disposed on an exterior peripheral surface of the internal component, wherein the second annular groove is bounded by two respective annular surfaces, wherein the second annular groove is aligned with the first annular groove, such that the first annular groove and the second annular groove form an annular space therebetween; and a retention O-ring disposed in the annular space formed between the first annular groove and the second annular groove.

Abstract: An example valve includes: (i) a pilot seat member comprising: (a) one or more channels fluidly coupled to a first port of the valve, (b) a pilot seat, and (c) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and (iii) a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion, wherein the solenoid actuator sleeve includes a first cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve and a second cross-hole disposed in the exterior peripheral surface of the solenoid actuator sleeve axially spaced from the first cross-hole.

Abstract: A pilot-controlled directional control valve, in particular a directional poppet valve, has a valve housing (10), at least three fluid connection points (12, 14, 16), a main control stage (18) and a pilot control stage. A further fluid-controlling intermediate stage (22) is arranged between the main control stage (18) and the pilot control stage (20). The main control stage (18) has a longitudinally movable main control piston (24). The pilot control stage has a longitudinally movable pilot control piston (26).

Abstract: A hydraulic cartridge valve includes a sleeve with a longitudinal bore that forms a working port via an end opening. A plunger is accommodated for linear motion in the longitudinal bore. The sleeve is penetrated in an inlet port region by a first radial bore that extends radially with respect to a longitudinal axis of the hydraulic cartridge valve. The sleeve is penetrated in a return port region by a second radial bore that extends radially with respect to the longitudinal axis. A first fluid flow path extends from the inlet port to the working port and a second fluid flow path extends from the working port to the return port. The plunger has third and fourth radial bores that extend radially with respect to the longitudinal axis and form part of the first and second fluid flow paths, respectively.

Abstract: A valve for a cold gas generator for an airbag in a vehicle includes: a valve chamber; a control chamber; a control piston; an overflow channel; a retaining element; and a shutoff element. The valve chamber includes an inlet from the cold gas generator and an outlet to the airbag. The control piston separates the control chamber and the valve chamber. The control piston is movable between an open position and a closed position, the control piston releasing the outlet in the open position and closing it in the closed position. The control piston has (i) a first active piston surface on the side of the valve chamber, and (ii) a second active piston surface on the side of the control chamber. The first piston surface is smaller than the second piston surface. The overflow channel fluidically connects the valve chamber and the control chamber to one another.

Abstract: A pilot-controlled pressure control valve is disclosed. The pilot-controlled pressure control valve has a pilot control stage, a spool valve, and an overload spring. The pilot control stage includes a pilot control piston which has a pilot control spring. The pilot control spring acts in a closing direction of the pilot control stage. The pilot control spring is supported on the spool valve which can be positioned by a control pressure against the force of the overload spring. The control pressure is configured to set a preload of the pilot control spring. At the same time, in a loaded position, in which the pilot control valve has minimum preload, the spool valve rests against a stop. A preload of the overload spring and a position of the stop can be set independently of one another.

Abstract: A pressure relief valve for a hydraulic press tool, the pressure relief valve having a valve body, a fluid return channel, a needle and a seat, and the needle is movable between a closed position, in which the needle is in contact with the seat to block the channel, and an open position, wherein the needle is at a distance from the seat to allow fluid to flow in the channel, and the fluid flow then causes movement of the seat away from the needle and completes the opening of the fluid return channel.

Abstract: A counterbalance valve is provided with load-sensing, hydro-mechanically setting, features. The counterbalance valve relief setting changes dynamically based on the load pressure at the load port of the counterbalance valve.

Abstract: A vapor isolation valve includes a first chamber in fluid communication with a fuel tank and a second chamber disposed with respect to the first chamber. A diaphragm is disposed between the first and second chambers, has an orifice allowing fluid communication therebetween, and is moveable between a diaphragm open position and a diaphragm closed position. A third chamber is disposed adjacent the first chamber, relative to the diaphragm, and is in fluid communication with an exit passage. The diaphragm open position allows fluid communication between the first and third chambers, and the diaphragm closed position substantially restricts fluid communication therebetween. A pilot valve is disposed between the second and third chambers and is selectively moveable between a pilot open position configured to allow fluid communication between the second and third chambers and a pilot closed position configured to block fluid communication therebetween.

Abstract: The invention relates to a sanitary insert part (1) having an insert housing (2), which (2) includes in a housing interior thereof a functional element (3) that controls throughflow and that has at least one throughflow orifice (4). The insert part according to the invention is characterized in that at least one throughflow opening (4) is delimited by a peripheral wall, the shape of which can be changed against a restoring force as a result of the pressure of the inflowing water in such a manner that the at least one throughflow orifice (4) has a variable orifice cross section which can be changed, in dependence on the pressure of the inflowing water, between an open position and a minimized position having a reduced orifice cross section by comparison.

Abstract: A proportional throttle valve includes a valve piston (2) displaceably guided in the longitudinal direction in a valve housing (3) having a fluid inlet (4) and a fluid outlet (5) and pretensioned by an energy accumulator, in particular in the form a pressure spring, against a stroke stop (6) defining the closure position. A pressure limiting valve (7) is integrated in the proportional throttle valve (1). The side (8) of the valve piston (2) to allow the piston to move away from the stroke stop (6) in opposition to the pretensioning force when a predefinable pressure is exceeded at the fluid inlet (4).

Abstract: A pressure control valve is provided, which includes a stopper having a flow path for preventing damping that is provided in a contact portion that is adjacent to an inner flow path of a main piston so that hydraulic fluid in the main piston is smoothly drained through a gap between stopper contact surfaces.

Abstract: A high flow pressure regulator valve is disclosed having an integral pilot valve. The disclosed valve includes a pressure regulating portion including inlet and outlet ports, a valve seat, valve disc and a spring for biasing the valve disc into engagement with the valve seat. The valve also includes a pilot valve portion positioned on the flow regulating portion. The pilot valve portion includes a pilot spring, a diaphragm and a pusher post. One end of the pusher post is positioned toward the diaphragm and a second end is disposed within an annulus region. The valve further includes a pressure path that enables selective fluid communication between the outlet port, the annulus, an inner chamber region disposed beneath the diaphragm, and an intermediate chamber disposed above the valve disc. Other embodiments are disclosed and claimed.

Abstract: A pressure control valve is provided, which can variably control the set pressure of a relief valve in accordance with pilot signal pressure that is controlled in an operator's seat and so on when the set pressure of the relief valve required in a replaced working device is changed.

Abstract: A pressure limiting valve has a control element (10) which can be acted on in an opening direction, against a first control face, by a pressure which is to be limited, and which can be acted on in a closing direction by a spring (16) and, against a second control face, by a control pressure prevailing in a control pressure space (14). The pressure prevailing in the control pressure space can be limited by means of a pilot control valve (21). A control fluid can be supplied to the control pressure space through the control element via a control fluid nozzle (48). Upstream of the first control face, a plate (38) is held on the control element. Formed between the plate and the first control face is a gap with a predefined gap dimension. Said gap is situated upstream of the control fluid nozzle.

Abstract: A pressure regulating device, a compressed air supply system and a motor vehicle are provided. The pressure regulating device comprises a first valve seat (301), a first valve plug (302), a second elastic body (314) and a first gas pipeline (307). A sliding sealing fit is provided between the first valve plug (302) and the first valve seat (301), and the first valve plug (302) divides the first valve seat (301) into a first chamber (305) and a second chamber (306). The second elastic body (314) is arranged in the second chamber (306) and supports the first valve plug (302). The first chamber (305) is connected with the first gas pipeline (307). The first valve plug (302) has at least two branch airways (323), each of which having a gas outlet (325). The first valve plug (302) has at least two third positions in which at least one gas outlet (325) is closed by the inner wall (321) and at least one of other gas outlets (325) leaves the inner wall (321).

Abstract: A hydraulic circuit of an option device for an excavator is disclosed, which can constantly supply hydraulic fluid to an option device, such as a breaker and so on, selectively mounted on the excavator, irrespective of the size of a load occurring when the option device operates, and control respective flow rates required for various kinds of option devices. The hydraulic circuit includes a variable hydraulic pump, an option device, a first spool shifted to control hydraulic fluid fed to the option device, a poppet and a piston, an option spool shifted to control hydraulic fluid fed to the option device via the first spool, a second spool shifted to control hydraulic fluid fed to a back pressure chamber of the poppet, and a control means installed in the poppet and controlling hydraulic fluid passing through an orifice of the poppet when the piston and the poppet are pressed by the hydraulic fluid fed from the hydraulic pump, through the shifting of the second spool.

Abstract: A hydraulic soft-start system includes a first flow valve in fluid communication with a pressure source and an inlet of a motor. A first restricting orifice is disposed between the first valve and the inlet. A second flow valve is in fluid communication with the first valve and the inlet. A pilot for actuating the second valve is in fluid communication with the inlet. A second restricting orifice is disposed between the pilot and the inlet. Upon actuation of the first valve, a first flow is passed from the pressure source via the first orifice to the inlet, placing the motor in a partially-actuated state. The second valve being actuated after a threshold pressure of the pilot is reached allowing a second flow to pass from the pressure source to the inlet. The second flow being higher than the first flow, thereby placing the motor in a fully-actuated state.

Abstract: The invention relates to a sequence valve for use in a hydraulic plant, which sequence valve has a pressure-controlled slide valve (5) with a spring return and in a starting position defines a first cavity (10), which cavity is connected with a tank and the hydraulic plant, and in a second, pressurized position closes off the connection with the tank. The cavity is connected to a second cavity (18) via a channel (15, 16, 17) in the slide valve, and the second cavity is adapted to be connected with a pump via a throttle (20) and is positioned on the same side of the slide valve as the spring (7). The sequence valve has a third cavity (19), which is adapted to be connected with the pump and is positioned on the opposite side of the slide valve from the spring, and the second and the third cavity are connected with each other via a fixed throttle with a short flow channel. The invention also relates to downhole tractor with the sequence valve.

Abstract: There is disclosed a variable metering orifice arrangement for a current divider and current adding device, the metering orifice arrangement including one or more working terminals by each of which a consumer can be supplied with pressure fluid. The metering orifice arrangement includes a metering orifice piston to which control pressure tapped off between two throttles of a pressure divider can be applied, wherein at least one of the throttles is variable.

Abstract: A flow control valve includes a pressure compensating valve and a first switching valve. The pressure compensating valve is configured to enlarge an opening area of a variable orifice between a load pressure line and a compensating pressure line when a pressure of working fluid of the compensating pressure line is smaller than a first set pressure, and narrow the opening area of the variable orifice when the pressure of the working fluid of the compensating pressure line is larger than the first set pressure. The first switching valve is configured to switch between a meter-out operation and a neutral operation by an external operation, wherein the working fluid of the compensating pressure line is drained in the meter-out operation, the working fluid of the compensating pressure line is not drained in the neutral operation. The load pressure line guides the working fluid to be supplied to an actuator.

Abstract: Pressure relief valves are described herein. An example pressure relief valve includes a body having external threads to threadably engage another body having a pressurized chamber. Additionally, the pressure relief valve includes a relief valve orifice that is threadably engaged with the body via internal threads of the body. The relief valve orifice includes a seating surface. Further, the pressure relief valve includes a pressure-balanced piston assembly that is slidably movable within the body relative to the relief valve orifice and the seating surface to control the flow of fluid between the pressurized chamber and the relief valve orifice.

Abstract: A holding control valve of the present invention is configured such that: a spool is configured to perform strokes by a piston configured to operate by introduction of pilot pressure and have a larger diameter than the spool; the piston is divided into a pilot piston configured to receive the pilot pressure and a relief operation piston disposed adjacent to the spool to receive pressure of relief oil discharged when a relief valve operates; and the relief oil is introduced to between the pilot piston and the relief operation piston.

Abstract: What is disclosed is a pilot-controlled pressure feed valve comprising a main stage and a pilot control stage, wherein the main stage comprises a piston that is biased into a closed position. The piston is provided with a piston bore through which an input port may be connected with a rear-side spring chamber. To this piston bore a throttle valve means is associated which provides a comparatively small cross-section of flow for the control oil in the pressure limiting function of the pressure feed valve, and a comparatively large cross-section of flow in the anti-cavitation function.

Abstract: A device for regulating a pressure and/or a volume flow of a fluid, including a cavitation chamber having a ram device, to generate a ram pressure region, and having at least one outlet orifice for a discharge of the fluid from the cavitation chamber, at least one cavitation region being able to be generated in the cavitation chamber, and the outlet orifice being situated so that the fluid flows between the cavitation region and the ram pressure region to the outlet orifice. Also described is a method for regulating a pressure and/or a volume flow.

Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system and tank pressure spikes. Because the pilot ball downstream of the damping orifice is held off the pilot seat in the normal starting condition by a pilot return spring, the main piston will open immediately when system pressure overcomes the low bias pressure of the main spring. A pilot pressure bypass port, which selectively deactivates the pilot chamber features, may also be included.

Abstract: An automotive vehicle includes a vehicle body and at least one reservoir containing a fire suppressant agent. A distribution system receives the fire suppression agent from the reservoir and conducts the agent to at least one location about the vehicle's body in response to the determination by a sensor system and controller that the vehicle has been subjected to a significant impact. The reservoir includes a discharge port controlled by a piloted spool valve actuated by pressure generated by a propellant device.

Abstract: A valve 100 comprising a magnetic circuit comprising a first member 101 and a pivotably mounted armature 102 the armature being movable between a position in which the valve seal 104 engages the valve seat 105 of valve port 103 to block the valve port 103, and a position away from the first member 101. A coil 106 surrounds the armature 102 which, when supplied with an electric current, creates a magnetic field in the armature 102 attracting the free end to the first member 101. Dampening pads 110 are provided on the armature 102. Each dampener pad 110 comprises a layer of viscoelastic material covered by a protective layer of polyetheretherketone (PEEK). During use, as there is wear between the armature 102 and the first member 101, and/or non magnetic section 107, the dampening pad 110 is compressed on impact by an increasing degree, thus the more worn the valve becomes, the more the dampening and thus the greater the protection against further wear.

Abstract: A pilot-operated pressure shut-off valve having a main control piston which, when an upper system limit pressure in the hydraulic system is reached, connects an inlet, via which pressure medium can be fed to a hydraulic system, to an outlet by taking up a first switching position and, when a lower system limit pressure is reached, separates from the outlet by taking up a second switching position. The pressure shut-off valve has a pilot valve arrangement by which the fluidic connection of a control space adjacent to the main control piston can be changed in order to control the main control piston, and which has a valve housing, with a first pilot piston and a second pilot piston accommodated within the first pilot piston for compact construction and capability to adjust the two pilot pistons mechanically completely independently of each other.

Abstract: A valve arrangement in a hydraulic circuit comprises a longitudinal duct 3 and a transverse duct 2. A throttle slide 10 can be displaced in the direction of the longitudinal duct 3. Arranged in the throttle slide 10 is a valve piston 25, by means of which the flow through the hollow throttle slide 10 can be enabled or blocked. The flow of hydraulic fluid takes place through two groups of passage holes 33a, 35a, which are arranged in the throttle slide 10. The interaction of pressure and flow direction of the hydraulic fluid, and also the restoring force of a slide spring 20 and a piston spring 30, achieves a situation where hydraulic fluid can flow through the valve arrangement in both directions but that a throttling action occurs only when the hydraulic fluid flows from the transfer duct 2 to the longitudinal duct 3 under increased pressure.

Abstract: Disclosed is a relief valve, in which a flow rate of hydraulic fluid is not greatly changed even when temperature is changed, and thus providing smooth operation and preventing foreign materials contained in the hydraulic fluid from being introduced into the relief valve. The relief valve is comprised of a sleeve provided with a high-pressure inlet and a tank fluid channel; a main poppet provided with an inflow fluid passage and a back pressure chamber; an annular fluid passage provided on a front end of the main poppet; a seat provided with a seat fluid channel communicating with the back pressure chamber; and a pilot poppet communicating the seat fluid channel with the tank fluid channel.

Abstract: A gas pressure regulator has an inlet for connection to an upstream gas line for flow of gas into the regulator under pressure and an outlet for connection to a downstream gas line for flow of gas out of the regulator at a reduced pressure. A pilot mechanism delivers a desired pilot gas pressure through a pilot passage. A main valve mechanism regulates the flow of gas through a main flow passage connecting the inlet and outlet of the regulator. The regulator has a piston chamber, and a piston operatively connected to the main valve mechanism and movable in the piston chamber. The main valve mechanism has a passageway between the piston chamber and the pilot passage whereby the pilot gas pressure is adapted to move the piston and thereby position the main valve mechanism to regulate the gas pressure at the outlet of the regulator.

Abstract: A spring-loaded pressure relief valve, particularly for containers of pressurized fluids, comprising a valve body that is associable with a container and forms a discharge port that is controlled by a main piston; an auxiliary valve is further provided, which controls a venting port and drives the intervention of the main piston, such main piston being accommodated in a cavity that is formed in the valve body and is open in an axial direction on the opposite side with respect to the venting port.

Abstract: A cartridge relief valve uses a piston design. The piston replaces a tube used in prior art relief valves. The piston makes the inventive relief valve easier to manufacture and more stable than prior art relief valves. This is due to the fact that, for a given size valve, the diameter of the piston is smaller than the diameter of the tube that it replaces. Furthermore, the diameter of the pilot seat of the inventive relief valve is also smaller than the diameter of the pilot seat of many prior art valves.

Abstract: Disclosed is a pilot operated relief valve, in which a balance system is provided to offset a tank pressure exerted on a piston, so that a setting pressure of a pilot poppet is not changed even when the tank pressure is changed, and thus a function of the relief valve can be stably performed. The pilot operated relief valve is comprised of a sleeve, a main poppet provided to be movable in the sleeve, a seat provided in the sleeve, a housing connected to a rear end of the sleeve, a pilot poppet provided to be movable in the housing, a piston moved by a pilot signal pressure, and the balance system offsetting the tank pressure exerted on the piston.

Abstract: The object of the present invention is to provide a solenoid control valve simple in construction and low in cost, realized by reducing the number of component parts, eliminating screw-joined portions, and minimizing the use of rubber O rings. A valve hole of a pilot valve, a hole of a bearing for supporting one end of a shaft of a solenoid, and a fitting hole in which is fitted one end of a sleeve, are formed along the same axis in a body. This makes it possible to accurately establish the concentricity of movable components of the solenoid when the sleeve is fitted in the fitting hole, and hence, a pilot valve element can be integrally formed with the shaft. Set values for a main valve and the pilot valve are adjusted by adjusting the amounts of insertions of a press-fit member and a bearing by press-fitting.

Abstract: A fuel supply apparatus having a fuel pressure regulator (60) for regulating the pressure of fuel discharged from a fuel pump (4) to a predetermined pressure, the fuel pressure regulator (60) including: a first chamber (62), formed in a case (61), into which fuel discharged from the fuel pump (4) flows, and a second chamber (63), into which the fuel flows via the first chamber (62); a fuel limiting means (64) disposed between the first chamber (62) and the second chamber (63), for limiting fuel flowing from the first chamber (62) into the second chamber (63); a pilot valve unit (65) having a passageway for opening to discharge fuel tank (2), when the fuel pressure in the second chamber (63) is more than a first set pressure (Pp); and a main valve unit (66) having a passageway for opening to discharge fuel into the fuel tank (2) when the fuel pressure in the first chamber (62) is equal to a second set pressure (Pm) between the first set pressure (Pp) and the predetermined pressure (Pi), whereby, in cases where

Abstract: The internally piloted dome loaded pressure reducing regulator includes a regulator body with a main valve portion and a pilot valve portion. The inlet is fluidly connected to the main valve bore which in turn is connected to the pilot valve bore. Each of the pilot and main valve members are spring urged to a closed position while the pilot valve is moved to an open position by a diaphragm when there is a decrease of pressure in the pilot chamber. A continuous fluid connection is provided from the pilot chamber, including through the main valve member, to a control chamber portion below a piston which is moved under pressure to open the main valve member. The piston has a bleed hole bottom chamber portion to the top control portion which in turn is fluidly connected to the outlet.

Abstract: A cartridge relief valve uses a piston design. The piston replaces a tube used in prior art relief valves. The piston makes the inventive relief valve easier to manufacture and more stable than prior art relief valves. This is due to the fact that, for a given size valve, the diameter of the piston is smaller than the diameter of the tube that it replaces. Furthermore, the diameter of the pilot seat of the inventive relief valve is also smaller than the diameter of the pilot seat of many prior art valves.

Abstract: The fitting, in particular a safety valve, operates according to the relief principle or according to the loading principle. The fitting is opened and closed by a plurality of control parts. The control parts are connected in series in the control line of the fitting and are each actuated by a control valve. The control parts open the fitting only when all the control parts are in a position which opens the fitting. The fitting closes as soon as even only one of the control parts is in a position which closes the fitting.

Abstract: A fluid flow regulator having a chamber comprising a port opening and a tapered pin disposed within the opening, for controllably restricting the cross-sectional flow area through the port. The tapered pin moves relative to the bore of the port that it is disposed in, under the influence of a pressure responsive diaphragm. A spring biases the pin towards the diaphragm. The diaphragm's movement is unaffected by any misalignment of the diaphragm with respect to the tapered pin and port, and the tapered pin's movement is unaffected by any diaphragm movement not in line with the port.

Abstract: The fitting, in particular a safety valve, operates according to the relief principle or according to the loading principle. The fitting is opened and closed by a plurality of control parts. The control parts are connected in series in the control line of the fitting and are each actuated by a control valve. The control parts open the fitting only when all the control parts are in a position which opens the fitting. The fitting closes as soon as even only one of the control parts is in a position which closes the fitting.

Abstract: There is described a demand valve for a breathing apparatus wherein a pilot jet of the demand valve is controlled by a pivoting lever resiliently held against a planar face in which the pilot jet is formed. The pilot jet is preferably formed in a land surface surrounded by a recessed area of the planar face, and opening of the pilot jet is effected by movement of a control projection mounted on the pivoting lever. The area of the control projection is preferably greater than the area of the land surface.

Abstract: In a hydraulic relief valve having a main poppet draining into a pressure-oil tank hydraulic fluid flowing into a sleeve from a hydraulic pump and a pilot poppet draining into the oil tank the hydraulic fluid upon the occurrence of a high pressure over a pressure value set in a back-pressure chamber of the sleeve, an annular interference-preventing projection is provided to be formed in an outer periphery of the sleeve to be placed at boundary portions of feedback paths of feedback fluid on the side of the main poppet which is drained past a throttle of the sleeve and feedback fluid on the side of the pilot poppet which is drained past a feedback fluid path formed outside the sleeve.

Abstract: A spring-loaded pressure relief valve, particularly for containers of pressurized fluids, comprising a valve body that is associable with a container and forms a discharge port that is controlled by a main piston; an auxiliary valve is further provided, which controls a venting port and drives the intervention of the main piston, such main piston being accommodated in a cavity that is formed in the valve body and is open in an axial direction on the opposite side with respect to the venting port.