The Cla-Val Model CRD18 Pressure Reducing Control automatically reduces a higher inlet pressure to lower outlet pressure. It is a direct-acting, spring-loaded, diaphragm type control regulator that operates hydraulically or pneumatically. This valve is held open by the force of the compression spring above the diaphragm and closes when the downstream pressure acting on the underside of the diaphragm exceeds the spring setting. The CRD18 senses downstream pressure directly.

Flow through the control responds to changes in downstream pressure. Turning the adjusting screw clockwise increases the delivery pressure, and turning it counterclockwise decreases the pressure. A resilient disc assures tight shut-off on dead-end service.