The structure of the graphite heating rod of the heating element of the vacuum heat treatment furnace directly affects the efficiency and service life of the vacuum heat treatment furnace, and the structural form of the graphite heating rod of the heating element of the vacuum heat treatment furnace is also one of the key issues in the design of the vacuum heat treatment furnace. According to the different structural forms of graphite heating rods of the heating elements of the vacuum heat treatment furnace, they can be divided into sheet, plate, ribbon, filament, squirrel cage rod, net, rod, etc.
In order to avoid the discharge of the heating element of the nickel-chromium alloy vacuum furnace in the vacuum, low voltage is generally used, and the spiral heating wire structure cannot be used at the same time, because the spacing of the spiral structure is small, which is easy to produce discharge and thermal deformation and cause short circuit. High melting point metal molybdenum, tantalum, tungsten in the form of wire, strip, plate as heater, its structure is many, but the general hope is to minimize the contact with refractory materials, insulating materials, so as to avoid chemical reactions, reduce the life of the heater. In order to improve the radiation surface of tungsten wire and give full play to the characteristics of tungsten wire material, a single tungsten wire can be wound into a tungsten wire mesh, and then form a cylindrical heater.
Due to the good processing performance of graphite, it can be made into plates, tubes, rods, tubes, cloths, belts and other shapes, so the structural types of graphite heaters are more diverse. For most of the heaters made of graphite tubes, rods and cylinders are connected with graphite connection blocks, which should be considered in terms of structure, convenient installation and maintenance, and most of them are currently developed and matched. Heaters made of graphite cloth or graphite tape can be fixed with graphite splints or graphite wedges. The connection of heaters made of graphite sheets is even simpler, and the graphite sheets can be connected directly to the water-cooled electrodes by means of molybdenum screws.