Patent ID: 8465603

Claim:
A method for controlling the flow of a process gas for the heat treatment of metal materials/workpieces in an industrial furnace ( 1 ), which has at least one treatment chamber ( 2 ), at least one burnoff point ( 4 ) having a first valve ( 4 . 1 ), and a regulator ( 5 ) having a pressure meter ( 5 . 1 ), wherein the process gas comprises a gas mixture ( 6 ) and is used as a flushing gas ( 6 . 1 ) and as a fresh gas ( 6 . 2 ), the method comprising the following steps: a) in a first step, with first valve ( 4 . 1 ) open, i) supplying a flow of the flushing gas ( 6 . 1 ) through a valve ( 7 ) to the industrial furnace ( 1 ), such that at least a portion of the flushing gas exits the industrial furnace through the first valve ( 4 . 1 ), and then ii) burning off the portion of the flushing gas that exits the industrial furnace through the first valve ( 4 . 1 ); b) in a second step, performed after said first step, closing the first valve ( 4 . 1 ) when a preset flushing time has elapsed or when a preselected carbon monoxide content is detected in the treatment chamber; and then c) in a third step, detecting a gas pressure in the industrial furnace and when a target gas pressure is detected, adjusting the valve ( 7 ) in such a way that a regulated flow of the process gas is provided as the fresh gas in a quantity sufficient to maintain the gas pressure in the furnace at or above the target gas pressure.