Operating principle – General
The direct acting PRV has 3 essential elements:
A – Main Valve Unit
B – Pressure Measuring Element (Bellows)
C – Adjust Spring
Changes in downstream pressure are sensed by the bellows, which expands or contracts depending on the pressure change.
The movement of the bellows will be directly transferred to the spring, which will open or close the main valve, thus keeping the downstream pressure at a certain level.