Hydraulic Relay with Shastomit or Galit valve
A relay installed on the valve in the field is activated by a solenoid at the control station.
Ooval valves are piloted hydraulic valves activated by line pressure. The pilot
valve has a spring-loaded diaphragm that is sensitive to downstream pressure. The pilot's spring is preset to the desired reduced pressure. The pilot valve maintains a constant downstream pressure by gradually opening and closing the Ooval valves at any flow rate.