LOW SUPPLY PRESSURE ALARM FOR GAS SUPPLY

摘要

The invention provides an in-line low supply pressure alarm device (3) which includes a hollow housing (1) with a gas inlet (2), a gas outlet (9), and an elongate internal chamber (6). A piston (7) within the chamber (6) for axial sliding between an alarm-on and an alarm-off position. The piston (7) includes a piston head (12) sealed in sliding engagement with an actuating compartment (13) of the chamber (6). The piston (7) includes an axially extending valve stem (16) with a lateral alarm port (17) in flow communication with the gas inlet (2). The valve stem (16) is in sliding engagement with an alarm plenum (6, 19, 20) within the chamber (6). The alarm port (17) of the valve stem (16) is in flow communication with the alarm plenum (6, 19, 20) when the piston (7) is in the alarm-on position. A biasing spring engages the piston (7) to bias against the pressure of gas in the actuating compartment (13) to the alarm-on position. The alarm is activated when low pressure is detected.