Diaphragm control valve for heating or water system - has built in safety device in form of material plug which enters into solution if diaphragm fails and effects closure of valve

摘要

The fluid enters through a port (A) and exits through a second port (B) after passing through a controlled orifice (4). Flow is fed back through a central path (5) formed in the spool (2) and acts on one side of a control diaphragm (10). A second diaphragm (14) is positioned with a spacer unit in between. Within the lower housing is a spring (19) loaded element operating on a piston rod (20). Located between the two is an element of material (24) which separates the piston when dry. In the event of a main diaphragm failure, the material enters into solution and is forced out through a porous material and the valve closes. ADVANTAGE - Provides safe operation in the event of diaphragm failure.