The Eardley Gas Alarm
Designed by Dr A M Wilson to overcome the inadequacies of then current gas failure alarms such as the Bosun. It was directly plumbed in to the anaesthetic machine, and a shutter was held down if oxygen and nitrous oxide pressures were normal. If either dropped, the shutter rose, occluding the rotameter controls and a bell rang. No external power source was needed. It is shown rising. Murray published details in 1965.

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