INDIAN RAILWAYS – SAFETY VALVE

SAFETY VALVE

DESCRIPTION

This “Pop” type safety valves are fitted in the pneumatic systems relieve Components form excess pressure. The setting pressure (blow – off pressure) is adjustable within certain limits with a given design of the spring. The closing pressure can be adjusted to give the required range. Between blow – off and closing pressures.

OPERATION

When air pressure below valve (9) is sufficient to overcome the pressure of spring (6), the valve lifts from its seat, exposes a larger area to the air pressure and is quickly moved up wards. In doing so it closes the two vertical ports A and opens ports B, which are drilled through the bush and the body, to atmosphere.

As the air pressure below the valve decreases, so that the spring is able to force the valve towards its seat, the valve downwards and uncovers the two vertical ports A in the bush. This allows the discharged air pressure to communicate with the spring chamber and, since communicate the spring chamber with atmosphere are the holes, which restricted by chock (5), the date valve chamber enters more rapidly than it can escape thorough these holes.