Ongoing air supply
August 1st 2006 Draeger's Automatic Switch Over Valve (ASOV) enables users to connect compressed air breathing apparatus (CABA) to an external air supply such as a factory ring main. Should the external supply fail, the valve automatically, and without interruption, switches to the back-up CABA.
The ASOV is connected between the output of the CABA first-stage pressure reducer and lung demand valve, and is attached to the primary airline supply by an additional input connection. If the primary air source fails, or the input pressure drops below the ASOV's switching pressure of 4 to 5 bar, the valve automatically switches over and an alarm alerts the user.
The warning sounds until the wearer leaves the hazardous area and removes the equipment or switching pressure is exceeded, at which point the valve will automatically switch back to the airline supply. The ASOV is designed to maintain positive pressure within the facemask at all times. More articles from Draeger Safety UK Limited: | 
