US Patent 9297465 Pilot-operated regulator with balanced port

A fluid regulating device includes a regulator valve, an actuator and a pilot regulator valve assembly. The pilot regulator valve assembly provides a pressure load to a surface of a diaphragm of the actuator in response to changes in downstream pressure being applied to the opposite surface of the diaphragm. An upper cavity of the pilot regulator valve assembly is in fluid communication with a control cavity of the actuator, allowing both the actuator diaphragm and the pilot regulator valve assembly diaphragm to simultaneously sense pressure variations within the cavities. As the downstream pressure varies, the diaphragms of both the actuator and the pilot regulator valve assembly displace to regulate the downstream pressure and the pilot regulator valve assembly maintains a load pressure. The regulator further includes a balanced regulator valve applying a balancing force to offset a force of upstream pressure on a balanced valve plug.