Gas quenching method using a recycling facility

Abstract

The invention relates to a gas quenching method of the type that makes use of (i) a quenching cell (V1) which is intended to receive objects to be quenched with a quenching gas and (ii) a buffer capacity (V2) which is designed to contain the quenching gas. The invention is characterised in that following a quenching operation, all or part of the gas contained in the cell (V1) is recycled in the following manner consisting in: obtaining a first intermediate storage balloon (V3) which can receive the quenching gas from the cell; after a quenching operation, performing one or more operations comprising the partial emptying of the contents of the cell (V1) into the first intermediate storage balloon (V3), by means of partial or total pressure balancing between the two volumes of the cell (V1) and the first intermediate storage balloon; transferring the gas stored in the first intermediate storage balloon (V3) to the buffer capacity (V2); and, if necessary, releasing part of the contents of the cell (V1) into the atmosphere.

Description

technical field [0001] The present invention relates to a method and an apparatus for recycling a gas or gas mixture used in a gas-cooled quenching operation. Background technique [0002] Air-cooled quenching of steels that have been vacuum heat treated (heating before quenching, annealing, stress relieving, etc.) . The gas may include nitrogen, air, argon, helium, or any other industrial gas or gas mixture. [0003] Improvements in rapid steel cooling methods in recent years have mainly involved the use of fluids with better heat transfer characteristics, such as helium and hydrogen, mixtures of inert and lighter gases (N 2 -H 2 , N 2 -He, etc.), and increasing the gas pressure and flow rate in the pressure vessel. At the same time, the quenching chamber technology has been improved: high working pressure, high heat exchange capacity, etc. [0004] Certain noble gases and gas mixtures, such as helium, require the use of a gas recovery system suitable for delivering a...

AI Technical Summary

Problems solved by technology

[0013] - With respect to gas cleaning plants: these generally make the plant more complex; moreover, conventional gas separation plants require either the use of separate compressor plants (see for example document US2002 / 0104589A1), or by running the above mentioned for recompression and transport of the gas compressor (see for example the example of document EP0450050) to compress the gas;

[0014] -Quench chamber out of service: The quench chamber is out of service for a significant portion of its duty cycle due to (limitations of) the recirculation method, making it incapable of performing load cooling functions

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