(1) strictly vacuum seal. Metal products for sintering or heat treatment are conducted in airtight vacuum furnace, so the furnace to obtain and maintain the original air leakage rate, ensure vacuum degree of vacuum furnace, and to ensure the quality of the products have very important significance. To ensure the vacuum performance of vacuum furnace, in vacuum furnace design must follow the basic principle is: furnace should use airtight welding; Opening or less as far as possible on the furnace body is not opening; Less use or avoid use dynamic seal structure to minimize the vacuum leak; Installed on the furnace accessories, such as water-cooled electrodes, thermocouple device must be designed sealing structure is deduced.
(2) heating and insulation material can only be used in the vacuum state. Vacuum resistance furnace heating and insulation work under high temperature and vacuum, resistance to high temperature, low steam are put forward for the material, radiation effect is good, and the requirements of small coefficient of thermal conductivity, the hangzhou oxidizing request is not high. Vacuum resistance furnace is widely used tungsten, aluminum, tantalum, and heating and thermal insulation materials such as graphite, and the material under the atmospheric conditions extremely easy oxidation, generally do not use them as regular resistance furnace heating material.
(3) the cooling unit. Vacuum furnace, furnace shell, furnace cover, electric heating element guiding device (water-cooled electrodes), middle vacuum hot insulation parts are in the condition of vacuum, heating work, in order to guarantee the structure deformation of parts, vacuum sealing ring heat, not burning, not all the parts should be set according to different situations water-cooling device, in order to ensure the normal operation of the furnace and have enough life.
(4) with low voltage, high current. When the vacuum degree within the scope of 0.1 a IO0Pa, under the high voltage electric conductor can produce glow discharge phenomenon, serious can produce arc discharge that burned electric heating element, insulation, etc. As a result, the working voltage of vacuum furnace electric heating element is generally not more than 80-100 - v. At the same time, the electric heating element structure design to take some effective measures, such as to avoid a cutting-edge parts, electrode spacing cannot be too small.
(5) requires a high degree of automatic.
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