A furnace system includes a heating chamber, a retort assembly, and a waveguide. The heating chamber includes a shell encompassing an insulation layer and a working volume, where the working volume is configured to receive at least one part for heat treatment. The retort assembly is supported within the insulation layer and includes an inner retort surface facing the working volume. The inner retort surface is formed of at least one carbon compound reflective of microwave radiation, and the retort assembly defines a retort aperture. The waveguide is configured to direct microwave radiation from a microwave source to the retort aperture.

The invention relates to a dental pressing furnace for producing a dental restoration element in a muffle (8) by heating and pressing a blank (14). The dental pressing furnace comprises a combustion chamber (6), comprising at least one guide opening (11) that is opened towards the outside and a pressing stamp (4) guided in the guiding opening (11) and protruding into the combustion chamber (6) for applying pressing force to the heated blank (14) in the muffle (8). A temperature transmitter (36) guided at least in part by the pressing stamp (4) is configured to guide a temperature (50) of the blank (14) in the combustion chamber (6) from said combustion chamber, and a temperature sensor (34) connected to the temperature transmitter (36) outside of the combustion chamber captures the temperature (50).

The invention relates to a dental pressing furnace for producing a dental restoration element in a muffle (8) by heating and pressing a blank (14). The dental pressing furnace comprises a combustion chamber (6), comprising at least one guide opening (11) that is opened towards the outside and a pressing stamp (4) guided in the guiding opening (11) and protruding into the combustion chamber (6) for applying pressing force to the heated blank (14) in the muffle (8). A temperature transmitter (36) guided at least in part by the pressing stamp (4) is configured to guide a temperature (50) of the blank (14) in the combustion chamber (6) from said combustion chamber, and a temperature sensor (34) connected to the temperature transmitter (36) outside of the combustion chamber captures the temperature (50).

A process for the production of potassium sulphate by conversion of potassium chloride and sulphuric acid using a muffle furnace, said furnace comprising a reaction chamber and a combustion chamber, wherein in the reaction chamber potassium chloride (KCI) and potassium hydrogen sulfate (KHSO.sub.4) are reacted to form potassium sulphate while supplying heat to the reaction chamber from the combustion chamber, wherein the combustion chamber has at least a pair of regenerative burners and wherein the process comprises the steps of alternatingly causing one of the regenerative burners to perform a combustion operation in the combustion chamber to heat the reaction chamber and another of the regenerative burners to perform a heat-regenerating operation in a regenerator, wherein the pressure in the combustion chamber is kept at a pressure of between 0.2 and 3 mbarg.

A process for the production of potassium sulphate by conversion of potassium chloride and sulphuric acid using a muffle furnace, said furnace comprising a reaction chamber and a combustion chamber, wherein in the reaction chamber potassium chloride (KCI) and potassium hydrogen sulfate (KHSO.sub.4) are reacted to form potassium sulphate while supplying heat to the reaction chamber from the combustion chamber, wherein the combustion chamber has at least a pair of regenerative burners and wherein the process comprises the steps of alternatingly causing one of the regenerative burners to perform a combustion operation in the combustion chamber to heat the reaction chamber and another of the regenerative burners to perform a heat-regenerating operation in a regenerator, wherein the pressure in the combustion chamber is kept at a pressure of between 0.2 and 3 mbarg.

A furnace may include a furnace muffle that can accommodate relatively larger workpieces than other furnaces. The furnace muffle may include a cover that includes one or more sets of plates. The plates may be configured to prevent sag during extended runtimes while still enabling the furnace to reach a temperature (e.g., a temperature between 1590 C. and 1650 C.) for sintering a workpiece. In some examples, the cover may include a first set of plates of a first material (e.g., a first alumina refractory material) and a second set of plates of a second material (e.g., a second alumina refractory material). The second material may have greater thermal conductivity than the first material. Accordingly, plates of the second set may be located in higher temperature zones of the furnace to enable efficient heat transfer from heater elements through the furnace muffle to a contact plate where a workpiece is heated.

A furnace may include a furnace muffle that can accommodate relatively larger workpieces than other furnaces. The furnace muffle may include a cover that includes one or more sets of plates. The plates may be configured to prevent sag during extended runtimes while still enabling the furnace to reach a temperature (e.g., a temperature between 1590 C. and 1650 C.) for sintering a workpiece. In some examples, the cover may include a first set of plates of a first material (e.g., a first alumina refractory material) and a second set of plates of a second material (e.g., a second alumina refractory material). The second material may have greater thermal conductivity than the first material. Accordingly, plates of the second set may be located in higher temperature zones of the furnace to enable efficient heat transfer from heater elements through the furnace muffle to a contact plate where a workpiece is heated.

A method for heat treatment, a heat treatment apparatus, and a heat treatment system that is capable of performing highly precise and efficient control of heat treatment. A heat treatment furnace has in-furnace structures made of graphite and has a heat-treatment chamber in which heat treatment of materials to be treated is performed. A value of G.sup.0 (standard formation Gibbs energy) is computed with reference to the sensor information from respective sensors, and an Ellingham diagram, a control range, and a status of the heat treatment furnace in operation expressed by G.sup.0 are displayed on a display device. A control unit controls a flow rate of neutral gas or inactive gas as atmosphere gas or a flow velocity of the gas so that G.sup.0 is within the control range.

A method for heat treatment, a heat treatment apparatus, and a heat treatment system that is capable of performing highly precise and efficient control of heat treatment. A heat treatment furnace has in-furnace structures made of graphite and has a heat-treatment chamber in which heat treatment of materials to be treated is performed. A value of G.sup.0 (standard formation Gibbs energy) is computed with reference to the sensor information from respective sensors, and an Ellingham diagram, a control range, and a status of the heat treatment furnace in operation expressed by G.sup.0 are displayed on a display device. A control unit controls a flow rate of neutral gas or inactive gas as atmosphere gas or a flow velocity of the gas so that G.sup.0 is within the control range.

A heat treatment device includes: a heating chamber inside which a treatment object is contained; a lower heater that heats the lower section of a receiving area that is an area inside the heating chamber in which the treatment object is contained; and an upper heater that heats the upper section of the receiving area.