Balanced single port thermostatic expansion valve

摘要

A thermostatic expansion valve for large-capacity refrigeration systems has a pressure-balanced valve pin and no means of communicating inlet pressures to the underside of the diaphragm. The valve pin has a coaxial bore, a pair of end faces, a pair of cylindrical portions fitting slideably in a feed bore leading to an outlet chamber, a reduced stem portion of small diameter between the pair of cylindrical portions, and a pair of shoulders connecting the reduced stem portion to the pair of cylindrical portions. The shoulders are exposed to the same pressure so that the valve pin is balanced.