Date of manufacture:
The Ritchie Whistle senses pressure that has become significantly reduced below 4 bar in the oxygen supply. It is designed to be used as an oxygen failure alarm on an anaesthetic machine where it is connected to the 4 bar oxygen circuitry. Low pressure causes the remaining gas to be directed through a whistle. This alarms momentarily every time a machine is disconnected from the pipeline supply. If it heralds the emptying of a cylinder, the whistle is prolonged. It cannot be disabled and has no other function. It is powered by the pressure that it senses. Once that pressure has fallen to the point that the whistle no longer sounds, no further alarm will occur.
Pressure Failure Alarm