Breathing gas heater for use by a diver comprising double walled cylinder and inner container filled with hot liquid prior to use

Claim 1

A portable gas heating apparatus for attachment to a pressurized gas source to help maintain diver comfort in a cold aqueous environment by producing heated breathing gas, comprising: a heat exchanger comprising metal tubing in an insulated walled chamber adapted to contain a hot liquid used to heat the breathing gas which circulates through said metal tubing; a heated liquid at 124°-160° F in said chamber which is charged to said chamber just preceding a dive by the diver, said liquid selected from the group consisting of fresh water, seawater, glycerol, ethylene glycol and mixtures of glycerol or said glycol with water; the volume of said liquid based upon the kind of breathing gas which is selected from the group consisting of air, oxygen, helium-air mixture and helium-oxygen mixture and delivering for every three pounds of heated fluid at 124° F a breathing temperature of between about 75° to 90° F for at least 90 minutes; and, inlet and outlet tubes to supply compressed gas to the heater and lead heated breathing gas from said metal tubing from said heat exchanger to the diver.