Knowledge of vacuum brazing furnace
Vacuum brazing furnace is divided into cold-wall vacuum furnace and hot-wall vacuum furnace from the basic structure. The hot-wall vacuum furnace has a simple structure and is mostly used in experiments. Most of the industrially used cold-wall vacuum furnaces are cold-wall vacuum furnaces.
Cold wall vacuum furnaces can be divided into many types according to structure and function. According to the structural layout, it is divided into vertical and horizontal; according to the number of vacuum chambers, it is divided into single, double and three chambers; according to the type of heating element material, it is divided into metal heating body furnaces, graphite heating body furnaces, etc.; according to the cooling method, it is divided into none Fast cooling function furnace, gas quenching vacuum furnace, oil quenching vacuum furnace, etc. In addition, vacuum furnaces can also be classified according to use function, cooling structure, vacuum level, temperature level, etc., such as aluminum brazing furnace, external circulation vacuum air quenching furnace, ultra-high vacuum brazing furnace, etc.
The cold wall vacuum brazing furnace consists of a vacuum furnace body, a vacuum system, a control system, a heating power supply, a water cooling system and a fast cooling system.
The furnace body of the cold wall vacuum furnace is mainly composed of heating elements, heat insulation elements and water-cooled furnace walls. Heating elements are mostly made of metal molybdenum belt or molybdenum wire, tungsten, tantalum, nickel-chromium, iron-chromium-aluminum and other metal electric heating elements and graphite electric heating elements. The heat insulation element is usually a reflective screen structure composed of multiple metal sheets and a graphite felt or ceramic felt structure. Its function is to maintain the high temperature of the internal heating zone and limit the heat in the heating zone to keep the furnace wall low heat input , So that the furnace wall is at a lower temperature under the action of water cooling.