Pressure boost attachment for pilot valves

摘要

A fluid pressure boost attachment (18) is attached to a pilot valve (16) which senses the fluid pressure in a main flow line F. Upon restriction or blockage of fluid flow through inlet line (32) to pilot valve (16) the correct static fluid pressure is sensed in auxiliary fluid chamber (126) of boost attachment (18). Boost attachment (18) is actuated upon a predetermined pressure differential being reached between chambers (100) and (126) thereby to move actuator (120) and place intermediate fluid chamber (24) of pilot valve (16) in fluid communication with outlet fluid chamber (28) thereof.