Most of the early designs of vacuum furnaces used the approach of all-metal shielding the heating modules. This type of screen-vacuum thermal insulation is a set vzaimoudalennyh apart metal sheets. The gaps between the sheets are approximately 5 mm. Typically, the first two or three layers are made of refractory materials (molybdenum, tantalum or tungsten - depending on the desired nominal temperature), followed by additional layers of stainless steel sheet. A specific feature of the use of screen-vacuum thermal insulation is its buckling. One of the reasons - the interaction of the internal screen with a heated evaporating material products. Moreover, this process is uneven, which affects the emission characteristics of the screen surface when heated at high temperatures. Therefore, one of the causes of non-uniformity of the heated articles the temperature is uncontrolled change the emissivity of certain areas of the screen insulation. This phenomenon is necessarily lead to a spread of properties of products in a heated cage.
As a material of the heating elements is used: molybdenum, tantalum, tungsten, nichrome, fechral.
These materials are available in the form of strips of broad bands or rods (circle). For insulators used various kinds of high-temperature ceramics. Screen-vacuum insulation, heating elements and electrical insulators are attached to the stainless steel core. The core can be in the form of a cylinder or box. There are many different types of all-metal construction of the heating modules. Such a variety of structural forms of all-metal heating module is not due to the improvement of the technical data, and, in general, the desire to circumvent the patents of competing companies. The heating unit is used in metal construction of the vacuum electric furnace at a nominal temperature of 2500 ° C. In such electric arc heaters basic material is tungsten. The higher the temperature, the shorter the service life of heaters. Reduced heater life happens for many reasons. Fig. 1 as an example shows the image of an all-metal heating module for the original design of the vacuum chamber furnaces trademark "NITTIN". In such an electric cage loaded horizontally (frontal).
These materials are available in the form of strips of broad bands or rods (circle). For insulators used various kinds of high-temperature ceramics. Screen-vacuum insulation, heating elements and electrical insulators are attached to the stainless steel core. The core can be in the form of a cylinder or box. There are many different types of all-metal construction of the heating modules. Such a variety of structural forms of all-metal heating module is not due to the improvement of the technical data, and, in general, the desire to circumvent the patents of competing companies. The heating unit is used in metal construction of the vacuum electric furnace at a nominal temperature of 2500 ° C. In such electric arc heaters basic material is tungsten. The higher the temperature, the shorter the service life of heaters. Reduced heater life happens for many reasons. Fig. 1 as an example shows the image of an all-metal heating module for the original design of the vacuum chamber furnaces trademark "NITTIN". In such an electric cage loaded horizontally (frontal).
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