Abstract: The invention relates to a method for the heat treatment of workpieces in a heat treatment furnace, wherein the treatment atmosphere in the heat treatment furnace is circulated. According to the invention, a propellant is injected into the heat treatment furnace in such a manner that the treatment atmosphere is essentially circulated by the injected propellant.

Abstract: The invention relates to a method for the heat treatment of workpieces in a heat treatment furnace, wherein the treatment atmosphere in the heat treatment furnace is circulated. According to the invention, a propellant is injected into the heat treatment furnace in such a manner that the treatment atmosphere is essentially circulated by the injected propellant.

Abstract: The invention relates to a gas generator, especially for generating treatment gas containing CO and H2, for heat treating metallic material at high temperatures. Said gas generator comprises at least one catalytic retort and has means for heating at least partial areas of the catalytic retort(s). According to the invention, the catalytic retort is divided into at least two retort areas (1, 2a, 2b, 2e) and at least one of the retort areas (1), preferably the retort area (1) located first in the direction of flow-through, is configured so that it can be removed from the gas generator.

Abstract: The invention relates to a process and apparatus for preparation of treatment gas used in heat treatments, whereby the treatment gas is produced in a furnace disposed catalyst retort at a temperature of that of the furnace in which the retort is positioned.With such processes, when using lower furnace temperature ranges, problems occur with respect to the reaction of the feed gas in the catalyst retort. To provide an improvement, the catalyst retort in the furnace is surrounded by a shield, and the treatment gas generated in and leaving the catalyst retort is first fed into a space defined by this shield and thereafter released into furnace space. By this, an isolation of the catalyst retort from the interior of the furnace is provided, and relatively higher retort temperatures are available.