SIMPLIFIED EXPLOSION-PROOF SYSTEM IN HAZARDOUS PLACE

摘要

PROBLEM TO BE SOLVED: To realize the explosion-proofness in a so-called 2nd grade hazardous place simply and securely with a low cost construction. ;SOLUTION: An electric apparatus 21 and a gas detector 22 which detects a hazardous atmosphere produced in a 2nd grade hazardous place are installed in a 2nd grade hazardous place where there is the possibility of producing a hazardous atmosphere in an abnormal state. A backup power supply 23 composed of a secondary battery such as a lead storage battery, etc., for the backup of power supply interruption is installed in a non-hazardous place. Further, a protective box 24 which is made to operate by the output of the gas detector 22 and cuts off the power supply route for the electric apparatus 21 is installed in the non-hazardous place. In a normal state, a commercial power supply current is rectified by a power supply circuit 25 to obtain a DC current which is supplied to the electric apparatus 21 and the gas detector 22 and, at the same time, supplied to the backup power supply 23 as a charging current. In a power supply interruption state, the electric apparatus 21 and a gas detector 22 are driven.;COPYRIGHT: (C)2000,JPO