ARI-PREsys® (Type PRS)

The pressure reducing station is a direct acting proportional regulator for regulating the pressure of fluid, gas and vapour media of Fluid Group II pursuant to Pressure Equipment Directive 2014/68/EU.
No auxiliary energy is needed.
In a pressureless state the valves (pos. 4 and 6) before and behind the pressure reducing valve are fully open, the bypass valve (pos. 8) is closed.
The media passes through the plant from the inlet to the outlet.
The pressure behind the pressure reducing valve is converted to the actuator over the control line (see Fig. 1).
For operating pressures above the allowable actuator temperature, for media (e.g. water for steam) a water seal pot is inserted in the control line.
The downstream pressure is converted over the actuator diaphragm of the pressure reducing valve in a force working in the disc closing direction.
The spring force is attained in the spindle over a pin and coupling and is opposed through the diaphragm force, therefore works in the disc open direction.
When both forces are equal, the valve is balanced, and the downstream pressure is maintained constant.
When the downstream pressure is altered the disc either „opens“ or „closes“.