Patent ID: 7632453

Claim:
A gas quenching method, of the type in which a quenching cell (V 1 ) receives objects to be quenched with a quenching gas, and comprising means for supplying pressurized quenching gas, connected to this cell, means for supplying gas comprising a buffer tank (V 2 ) for containing quenching gas, characterized in that, after a quenching operation, all or part of the gas contained in the cell (V 1 ) is recycled as follows: a) a main line connects the cell (V 1 ) to said buffer tank (V 2 ) via a compressor or booster set comprising one or more compressors/boosters in parallel (C 1 , C 2 , etc.); b) a first intermediate storage tank (V 3 ) receives quenching gas from the cell and feeds the compressor/booster set, and is located on a bypass of the main line; c) after a quenching operation, the contents of the cell (V 1 ) are emptied in one or more operations into the first intermediate storage tank (V 3 ) by partial or complete pressure balancing between the two volumes of the cell (V 1 ) and of the first intermediate storage tank; d) the gas stored in said first intermediate storage tank (V 3 ) is transferred to the buffer tank (V 2 ) via the compressor/booster set; and if necessary, part of the content of the cell (V 1 ) is released to the atmosphere.