BLOW-OFF VALVE

Typical Number in Hospital:

Cost Bands:

References: 2

This is a pressure relief valve intended to prevent the build-up of pressure beyond safe limits. It normally consists of a plunger and a spring of adjustable tension. Such valves are found in anaesthetic equipment and, incidentally, in any steam pressure apparatus (e.g. autoclaves). An example of the use of a pressure relief valve in an anaesthetic circuit would be to limit the pressure which can be applied to the patient's lungs by an anaesthetic machine to (say) 60 cmH2O. Sometimes blow-off valves are used as pressure regulators by allowing them to vent surplus gases, thereby retaining the circuit pressure at the blow-off pressure.