A pneumatic trip valve that may include a valve structure, a switch plate air path and an internal check valve. In various aspects, the pneumatic trip valve may be connected to a valve positioner, an actuator, or a combination thereof to control the operation of a fluid process control valve. In operation, the Pneumatic trip valve acts to put the actuator in a preset fail-safe position when the actuator loses sufficient pressure or communication from a main air supply, stored pressurized air from an actuator air reservoir, and/or an external air reservoir.

An intermittent air blow gun (10a) has a switching valve (26) including a switching-valve case (27) and a valve assembly (31), and the valve assembly (31) includes: a valve body (53) configured to open and close a valve hole; a small-diameter piston (33) partitioning so as to form a small-diameter pilot chamber (34); and a large-diameter piston (37) partitioning so as to form a large-diameter pilot chamber (38). The valve body (53) is switched to a closed position when air discharged from an inside of the switching-valve case (27) to an air discharge section (24) is supplied to the large-diameter pilot chamber (38) through a bypass flow path (77), and the valve body (53) is switched to an open position when air is exhausted.

An intermittent air blow gun (10a) has a switching valve (26) including a switching-valve case (27) and a valve assembly (31), and the valve assembly (31) includes: a valve body (53) configured to open and close a valve hole; a small-diameter piston (33) partitioning so as to form a small-diameter pilot chamber (34); and a large-diameter piston (37) partitioning so as to form a large-diameter pilot chamber (38). The valve body (53) is switched to a closed position when air discharged from an inside of the switching-valve case (27) to an air discharge section (24) is supplied to the large-diameter pilot chamber (38) through a bypass flow path (77), and the valve body (53) is switched to an open position when air is exhausted.

A pneumatically operated gas valve mounted on a vessel containing pressurized gas. The gas valve includes a piston positioned in a cylinder with one closed end so that the piston seats against a gas outlet to close the gas valve. A control reservoir is formed in the cylinder between the piston and the closed end of the cylinder. Upon filling vessel, some of the pressurized gas enters the control reservoir to provide a control pressure behind the piston. Actuating the control mechanism vents the control reservoir, resulting in the gas valve opening rapidly to release the pressurized gas in the vessel through an exhaust port of the gas valve.

A pneumatically operated gas valve mounted on a vessel containing pressurized gas. The gas valve includes a piston positioned in a cylinder with one closed end so that the piston seats against a gas outlet to close the gas valve. A control reservoir is formed in the cylinder between the piston and the closed end of the cylinder. Upon filling vessel, some of the pressurized gas enters the control reservoir to provide a control pressure behind the piston. Actuating the control mechanism vents the control reservoir, resulting in the gas valve opening rapidly to release the pressurized gas in the vessel through an exhaust port of the gas valve.

A combination valve includes a valve seat, a diaphragm valve element, a pilot system to automatically bring the diaphragm valve element into or out of contact with the valve seat by use of air pressure, and a manual system to hold the diaphragm valve element in contact with the valve seat even while air pressure is supplied. In the combination valve, a piston rod is provided such that, when the handle is turned to move the manual stem in a seating direction while the diaphragm valve element and the valve seat are separated from each other, the piston rod moves in the seating direction relative to a first piston and a second piston that are pushed by the air pressure in a separating direction.

A combination valve includes a valve seat, a diaphragm valve element, a pilot system to automatically bring the diaphragm valve element into or out of contact with the valve seat by use of air pressure, and a manual system to hold the diaphragm valve element in contact with the valve seat even while air pressure is supplied. In the combination valve, a piston rod is provided such that, when the handle is turned to move the manual stem in a seating direction while the diaphragm valve element and the valve seat are separated from each other, the piston rod moves in the seating direction relative to a first piston and a second piston that are pushed by the air pressure in a separating direction.

To prevent a defect in which particles such as impurities flow into a liquid that flows in from an inlet flow path and discharged from an outlet flow path. Provided is a suck-back valve including: a housing part; a valve element part; a diaphragm part; an open-close mechanism that brings the valve element part and a valve seat part into contact or separates the valve element part and the valve seat part from each other to switch between a closed state and an open state; and a suck-back mechanism that moves the diaphragm part in a direction in which the diaphragm part separates from the valve seat part to increase a volume of a valve chamber. The valve element part and the diaphragm part are molded integrally, the open-close mechanism is disposed in an adjacent space, and the valve element part and the open-close mechanism are coupled in the adjacent space.

To prevent a defect in which particles such as impurities flow into a liquid that flows in from an inlet flow path and discharged from an outlet flow path. Provided is a suck-back valve including: a housing part; a valve element part; a diaphragm part; an open-close mechanism that brings the valve element part and a valve seat part into contact or separates the valve element part and the valve seat part from each other to switch between a closed state and an open state; and a suck-back mechanism that moves the diaphragm part in a direction in which the diaphragm part separates from the valve seat part to increase a volume of a valve chamber. The valve element part and the diaphragm part are molded integrally, the open-close mechanism is disposed in an adjacent space, and the valve element part and the open-close mechanism are coupled in the adjacent space.

An operating structure of a pilot-operated solenoid valve is provided. The pilot-operated solenoid valve includes a valve body having a main valve orifice and a pilot valve orifice to open and close the main valve orifice. The pilot valve orifice communicates with an accommodating chamber of the valve body. The operating structure includes a knob, an adjustment rod, and a water stop nut. The knob is positioned and fitted to an opening of the accommodating chamber. The adjustment rod is hermetically fitted in the accommodating chamber. One end of the adjustment rod is threadedly connected to the knob, and the other end of the adjustment rod is connected to the water stop nut. The adjustment rod is driven to move axially by rotation of the knob for driving the water stop nut to control the opening and closing of the main valve orifice.