The Vanginot respirator, which is coming into increasing use in the mines of France, has been in service several years in the Paris fire department. This respirator, being of the compressed air type, furnishes the user with a continuous supply of fresh air and thus without the old of any cooling device. The explanation of this is the large absorption of heat due to the expansion of the air, which lowers the temperature of the containing flasks considerably and keeps them cool even in a heated atmosphere.
The Vanginot apparatus consists of three parts—a battery of accumulators, an indicating reducing gauge and a respiratory mask or helmet. The battery of air accumulators, which is composed of two steel desks, is charged at a pressure of 2,130 to 3,150 pounds per square inch by means of it compressor constructed specially for the service. The volume of air thus stored is sufficient for on hour to an hour and a quarter’s use.
The indicating reducing gauge, as its name indicates, lowers the pressure of the air contained in the desks to an ordinary tension and supplies the user with a volume of expanded air which may be further regulated by means of a so called regulating valve, supplying a greater or less volume, according to respiratory needs. This reducer recorder is also employed to operate an alarm whistle wanting the rescuer of the reduction of pressure and of the approaching exhaustion of the compressed air supply.