ESP Pressure Sensors and Relays

Complete line of pressure monitoring and control valves


In addition to our broad range of actuators, we offer a complete line of pressure monitoring and control valves, including ESP pressure sensors (stick pilots or hi-lo pilots) and PRV relays.

ESP pressure sensors are designed to detect abnormal operating conditions in a safety system and transmit a signal to perform a specific shutdown. The Axelson™ stick pilots have long been an industry favorite due to a sensing range of 0.25 to 20,000 psig and repeatability within 3% of the set point.

Along with the Axelson ESP, we offer a PRV relay device to control high pressure with lower pilot pressure, and we provide these as a three-way or two-way block and bleed.

NOV ESP pressure sensors and PRV relays are used in conjunction with the ESPHL high-low pressure controller, a basic safety system unit that provides a means for programming the automatic operation of a surface safety valve.

The ESP pressure sensors (stick pilots) in the unit sense predetermined high and low-pressure limits selected by the installation requirements. On sensing either of these limits, the unit is designed to close the surface safety valve. The sensing range of the ESPHL controller is 0.5 to 10,000 psi, the maximum instrument pressure through the sensors to the bottom of the relay is 200 psi, and the maximum control pressure through the relay is 375 psi.

One alternative to the ESP pressure sensor is the our ECS pressure sensor. The ECS pressure sensor may be used as a high- or low-pressure sensor by selecting the proper instrument pressure inlet and setting the desired operating pressure. Preselected pressure settings are made by adjusting the spring force acting against the sensor stem. Once in operation, the sensor is designed to allow instrument pressure to flow from the inlet to the outlet until the sensing pressure rises or drops beyond predetermined settings. Once the threshold is broken, the sensor blocks the incoming instrument pressure and back-bleeds the downstream pressure to the atmosphere through the alternate port.

  • Surface Safety Products Catalog

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