The Petro Controls “RHB” is a 2 way, normally open or normally closed, automatic, hydraulic, pressure sensing device.
By choosing the appropriate inlet, the sensor can detect pressure above (PSH) or below (PSL) any desired
pressure setting. By selecting the correct piston assembly & spring combination (See Pressure Chart), and either loosening or tightening the adjustment bolt, the sensor may be set between 3 and 10,000 PSI. It is normally installed on a process vessel, process flow line, or in a control panel. The sensor receives sensing pressure (Port P) from the component which it is monitoring and hydraulic supply pressure (Port A or B) from the safety system which it will shutdown.
During normal operation, the sensing pressure (Port P) should remain either above or below the desired setting.
This will allow supply pressure (Port A or B) to be blocked and the exhaust (Port A or B) open to the reservoir.
When the sensing pressure (Port P) rises above or falls below the set pressure, the sensor will bleed the supply pressure (Port A or B) through the exhaust (Port A or B); thus closing the actuator or system.
When the sensing pressure (Port P) returns to normal operating limits, the sensor will automatically reset.