US Patent 7121298 Reducer valve for pressurized gas

A reducer valve for pressurized gas includes a piston (2) displaceably mounted in a valve housing (3) against the force of a pressure spring (8). At one end, the piston (2) is subjected to pressure by the back pressure via a control pressure line (20) whereby the gas, which flows in from a pressurized gas source via a gas inlet (17), is throttled. The reducer valve is improved so that a specific gas volume remains in the connected pressurized gas source below a minimum pressure. A directional valve (24, 25) is provided in the control pressure line (20) and opens above a predetermined limit pressure.