Pressure reducing device

A pressure reducing device comprising an upstream end configured to be connected to a pressurized gas source and a downstream end configured to be connected to a coupled installation and comprising:

• an operational fluid circuit comprising a pressure reducing unit configured to reduce a pressure of a pressurized gas flow to a maximum pressure PA, an emergency shut-off valve and an outlet interface with a pressure capability PN, a relief fluid circuit comprising a first end connected to the operational fluid circuit downstream of the pressure reducing unit and a safety relief device,
• the relief fluid circuit comprising a second end connected to the emergency shutoff valve, and that the safety relief device is configured to have at least two states, a closed state where the safety relief device is inactive and the emergency shutoff valve is open, when the pressure in the fluid circuit downstream of the pressure reducing unit is lower than a predetermined pressure PL, and an open state where the safety relief device is active and the emergency shutoff valve is closed, when the pressure in the fluid circuit downstream of the pressure reducing unit is higher than the predetermined pressure PL,
• the predetermined pressure PL being between PA+5% and PA+500% and/or between PN+5% and PN+500% wherein the operational fluid circuit comprises a residual pressure valve and/or a non-return valve, further comprising a bleeding valve,
• wherein a central part of the residual pressure valve comprises a second piston, and in that a middle chamber is delimited by a first piston and the second piston, and that in the open position of the safety relief device, the bleeding valve is moved in a closed position by the second piston.