A fluid flow control unit, in a preferred embodiment, mounted on a section of pipe having a tubular wall forming a fluid flow passage with a flow axis, the unit having a gate section, and a gate pivot section, the pivot section having a body portion mounted on the pipe outer wall surface, a gate mounting cavity formed in the body portion and opening through the pipe wall and providing an access port for the gate section to the mounting cavity, a pivot shaft positioned in the cavity and mounted on bearing structure on the body portion, the diameter of the shaft being dimensioned to allow a laterally curved gate which is affixed to a surface portion of the shaft to pivot up against a ceiling of the pipe to thereby be out of the flow passage main stream at a full open, non-blocking position of the gate, and a gate position control structure on the unit for allowing predetermined degrees of rotation of the pivot shaft in response to the magnitude of fluid flow pressure forces directed against the gate.

A plunger-type diaphragm valve is disposed in an accommodation trough of a flush device. The accommodation trough communicates with an inlet passage and an outlet passage. The valve includes a control unit. One end of the control unit is provided with a diaphragm member and an engaging member, and another end leans against the outlet passage to block the inlet passage and the outlet passage. An outer wall of the diaphragm member is fixed to the accommodation trough. The diaphragm member has a curved portion. When the valve is actuated, the curved portion is deformed by water pressure to bring the control unit to move away from the inlet passage for the inlet passage to communicate with the outlet passage. The stressed area of the diaphragm member is small and the deformation is less, so the diaphragm member won't wear. The valve is durable and has a long life.

A hydraulic actuator to which a limit-adjustable mechanical lock device is applied, comprising: a housing having a first hole; side covers coupled at both sides of the housing, and having holder insertion holes formed to be opened toward the first hole side of the housing, and plugs; a first holder of which one side of the outer peripheral surface is inserted into the holder insertion hole at the plug side of the side cover by screw coupling; a second holder fitted and coupled to the inner peripheral surface of the side cover and having one end thereof screw-coupled to the second hole of the first holder; a locking means into which a rod is inserted so as to be movable in an axial direction at a predetermined distance across the second hole of the first holder and the third hole of the second holder.

A pressure reducing valve has a seal member, which is mounted on a side wall of a piston. The seal member is arranged between a first ring and a second ring. Consequently, depending on the direction of displacement of the piston, the first ring or the second ring is positioned on one of a displacement direction upstream side or a displacement direction downstream side of the seal member. The first ring and the second ring are made of a resin material, for example a polytetrafluoroethylene resin or a polyetheretherketone resin, having lower coefficient of friction compared with that of the seal member.

Fluid control valve assemblies for use in fire protection sprinkler systems to control the flow of firefighting fluid to the system sprinklers. The assemblies include a pressure-operated fluid control valve having an internal fluid chamber in which fluid contained therein acts on an internal diaphragm to control the flow of fluid from an inlet to an outlet of the valve. An environment-responsive control device in fluid communication with the internal fluid chamber along a first fluid communication line controls the flow of fluid out of the fluid chamber to initiate actuation of the valve. A fluid-flow latch in fluid communication with the outlet of the valve along a second fluid communication line subsequently controls the simultaneous flow of fluid out of the fluid chamber and the actuation of the valve.

The pressure-type flow control device includes: a main body provided with a fluid channel communicating between a fluid inlet and a fluid outlet and an exhaust channel communicating between the fluid channel and an exhaust outlet; a pressure control valve fixed to a fluid inlet side of the main body for opening or closing the upstream side of the fluid channel; a first pressure sensor for detecting the internal pressure of the fluid channel on the downstream side of the control valve; an orifice provided in the fluid channel on the downstream side of the point of branching of the exhaust channel; an on/off valve for opening or closing the fluid channel on the downstream side of the first pressure sensor; and an exhaust valve for opening or closing the exhaust channel.

The pressure-type flow control device includes: a main body provided with a fluid channel communicating between a fluid inlet and a fluid outlet and an exhaust channel communicating between the fluid channel and an exhaust outlet; a pressure control valve fixed to a fluid inlet side of the main body for opening or closing the upstream side of the fluid channel; a first pressure sensor for detecting the internal pressure of the fluid channel on the downstream side of the control valve; an orifice provided in the fluid channel on the downstream side of the point of branching of the exhaust channel; an on/off valve for opening or closing the fluid channel on the downstream side of the first pressure sensor; and an exhaust valve for opening or closing the exhaust channel.

A tray is provided between a supply air port member and an exhaust port member. A peripheral edge portion of an opening portion of an exhaust port of the exhaust port member that faces an output chamber side is a conical guiding portion. A spherical body is disposed between the guiding portion and an inner bottom face of a tray. The inner peripheral wall of the tray fits slidably into the outer peripheral surface of the end portion of the exhaust port member positioned within the output chamber. The other end of the poppet valve is caused to contact the outer bottom face of the tray. Thus, the exhaust port and the spherical body are centered automatically at the position of the center of the exhaust port, regardless of the position of the shaft axis of the poppet valve, so that there will be essentially no sliding friction.

To avoid formation of surface sag formed when an internal flow path of a valve element is processed and to ensure a maximum flow rate in a fluid control valve where a seating surface of the valve element is formed of a resin layer, in a fluid control valve that includes a valve seat, and a valve element including resin layers provided in concave grooves formed on a facing surface facing the valve seat, the valve element further includes internal flow paths whose inflow ports are opened in a back surface facing away from the facing surface and whose outflow ports are opened in portions around the concave grooves on the facing surface, and counterbored portions are formed on sides of the inflow ports of the internal flow paths.

To avoid formation of surface sag formed when an internal flow path of a valve element is processed and to ensure a maximum flow rate in a fluid control valve where a seating surface of the valve element is formed of a resin layer, in a fluid control valve that includes a valve seat, and a valve element including resin layers provided in concave grooves formed on a facing surface facing the valve seat, the valve element further includes internal flow paths whose inflow ports are opened in a back surface facing away from the facing surface and whose outflow ports are opened in portions around the concave grooves on the facing surface, and counterbored portions are formed on sides of the inflow ports of the internal flow paths.