Patent ID: 8858688

Claim:
An intrinsically safe, self-contained toxic gas removal and air conditioning system for use in an underground mine survival chamber to continuously remove contaminant CO 2 or CO or both from the air sealed in the survival chamber as introduced by the respiratory exhalations of chamber occupants, said system comprising: an explosion proof and flame proof external shell rated to withstand a 15 psi external explosive force; an internal battery capable of at least 96 hours of continuous operation, said battery having insufficient water to provide the lowest explosive level of hydrogen under the worst conditions; a fan motor mounted inside said external shell and driven by a fan motor/driver control circuit, said fan motor operatively coupled to a driveshaft that extends to the outside of said external shell; and a power supply circuit in communication with said fan motor/driver control circuit, said power supply circuit including an AC power loss circuit to detect the loss of externally-provided AC power, and automatically starting operation of said fan motor when the loss of externally-provided AC power is detected.