METHOD FOR CUTTING IN CLOSED WORKING SPACE FOR HANDLING HARMFUL SUBSTANCE

摘要

[PROBLEMS] To improve a working environment for cutting a member, to be cut, containing a harmful substance in a closed space by thermal cutting, which is relatively easily in work, and thus to ensure safety for workers. [MEANS FOR SOLVING PROBLEMS] A member to be cut is flame-cut with a flame torch (16) within a close working house. The construction of the flame torch (16) is such that a preheating flame (52) of a hydrogen gas, a propane gas, or an oxygen gas, which increases the susceptibility of the member to burn, is produced around the outer peripheral part, and an oxygen gas is blown out to the center part to produce a cutting oxygen gas stream (53). Cutting is carried out by heating the member (4) to be cut to the ignition temperature with the preheating flame (52), spraying an oxygen gas against that part to burn the member (4), melting the member (4) by the heat, and, at the same time, blowing off limewash and slag produced by the combustion by blowing force of the cutting oxygen gas stream (53). In this state, the flame torch (16) is moved in a direction indicated by an arrow to successively remove the member (4) by the preheating flame (52) and the cutting oxygen gas stream (53) and thus to cut the member (4) into a groove shape.