DR20 Direct-Acting Pressure Reducing Valve

The DR20 regulates pressure via the adjustment of a valve that constricts the flow of steam. When the adjustment handle is fully loosened, there is no force acting on either the adjustment spring (the larger of the two) or the valve stem. In this configuration, the main valve will remain sealed by the force of the small spring situated beneath.

Turning the adjustment handle clockwise will cause the screw to exert force on the adjustment spring, compressing it. As this compression pushes the stem downward, the smaller spring under the main valve begins to compress, allowing the main valve to open.

When the main valve is open, steam is able to flow through. By operating the adjustment handle, it is possible to achieve the specific pressure required for your system.

During operation, the secondary pressure exerts force on the adjustment spring via the bellows, causing the spring to compress or expand in response to fluctuations in secondary pressure.

When secondary pressure drops, the amount of force acting on the larger spring is reduced, causing it to expand and allow the main valve to open. This allows more steam to flow through, restoring secondary pressure back to higher levels.

When secondary pressure rises, the force acting on the larger spring grows stronger, causing it to compress and further constrict the flow of steam. As a result, the secondary pressure is reduced.