Gas-operated valve

A gas-operated valve for a fire suppression system, the gas-operated valve comprising:

• a body, a piston, and an integrated plug valve,
• the body configured to receive the piston axially therein, and
• the piston being movable within the body between a first axial position in which the piston is configured to seal a valve opening when pneumatic pressure provided by a non-flammable gas is applied to the piston and a second axial position in which the piston is configured to be withdrawn from the valve opening such that a pressurised fire suppression material can enter the body through the valve opening,
• wherein the piston comprises a machined flange which defines volumes for non-flammable gas and pressurised fire suppression material respectively separated by the machined flange,
• the integrated plug valve configured to control application and release of the pneumatic pressure and indirectly discharge of the fire suppression material,
• wherein the plug valve comprises a rotatable plug comprising a stem with a transverse bore for passage of the non-flammable gas, a blind bore in the body configured to receive the stem, and a stem seal between the stem and blind bore providing a fluid-tight seal between the stem and the blind bore thereby to prevent reduction of the pneumatic pressure by escape of the non-flammable gas between the stem and blind bore and allowing the stem to rotate within the blind bore, and
• wherein the blind bore comprises at least one or two annular grooves on an inside surface of the blind bore for receiving a portion of the stem seal thereby providing a further fluid-tight seal.