Pressure difference regulator with switching valve control - has externally triggered valve in low pressure orifice line closed to provide closure of regulator

摘要

A pressure difference flow regulator for use in heating system has a built in facility or electrical system. An orifice plate located in a supply line provides a pressure differential between two lines coupled to the diaphragm stage of a regulating valve. The low pressure downstream line has an on-off control valve and a by-pass has a restrictor before being connected to the output of the regulator. In operation, when the control valve is open a normal differential pressure controls the regulator. When the control valve is actuated by either a pneumatic or electrical signal, the pressure on the top side of the diaphragm falls at a rate fixed by the resistrictor and eventually the regulator closes. Typically the closing time is 30 seconds.