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Wire-wound spiral electric heating radiant tube: This type of electric heating radiant tube consists of a heat-resistant alloy steel sleeve and a heater. The heater is generally made by winding φ3-5 mm heating wire around a heat-resistant insulating ceramic core with spiral grooves. Operating voltage: 220V, power: generally 5-7KW.
2. Ribbon-wound spiral electric heating radiant tube: The structure of this heater is basically the same as the first type, except that the heating element is made of resistance ribbon. The resistance ribbon is generally 1-3 mm thick and 10-20 mm wide. The core is also mostly composed of multiple segmented cores. Under the same surface load, the heat radiation area is larger, and material can be saved. Generally, high-power point heating radiant tubes adopt this form.
Description of electric heating radiant tubes:
1. Wire-wound spiral electric heating radiant tube: This type of electric heating radiant tube consists of a heat-resistant alloy steel sleeve and a heater. The heater is generally made by winding φ3-5 mm heating wire around a heat-resistant insulating ceramic core with spiral grooves. Operating voltage: 220V, power: generally 5-7KW.
2. Ribbon-wound spiral electric heating radiant tube: The structure of this heater is basically the same as the first type, except that the heating element is made of resistance ribbon. The resistance ribbon is generally 1-3 mm thick and 10-20 mm wide. The core is also mostly composed of multiple segmented cores. Under the same surface load, the heat radiation area is larger, and material can be saved. Generally, high-power point heating radiant tubes adopt this form.
3. Axial zigzag cage-type electric heating radiant tube (commonly known as squirrel-cage type): Its structure involves bending the resistance wire (ribbon) of the heating element into a "U" shape, inserting it into multiple insulating high-temperature-resistant ceramic support plates, and fixing it with a heat-resistant rod in the middle. Typical effective length: 900-2400; typical sleeve outer diameter: φ80-φ280. Single tube power: 2kW-40kW; single tube voltage: 30V-220V. This type of radiant tube has a longer service life.
The inner core of the electric heating radiant tube consists of U-shaped axially arranged resistance wires welded at the ends and ceramic support frames. There is no shielding between the inner core and the outer protective sleeve, ensuring good heat dissipation. For electric heating radiant tubes with a rated working temperature of 1000°C, the resistance wire material is Cr20Ni80 or 0Cr21Al6Nb, with a surface working temperature up to 1200°C. The maximum working temperature of electric heating radiant tubes using this material can reach 1000°C. The support frames are made of high-alumina ceramics. The outer protective sleeve is a cold-drawn seamless thin-walled heat-resistant steel tube, made of 1Cr25Ni20Si2 or 1Cr25Ni35Si2. This material has excellent high-temperature oxidation resistance, high creep strength, and certain carburization resistance. The design and material selection of this radiant tube have a large safety factor. For electric heating radiant tubes with a rated working temperature of 1200°C, the resistance wire material is 0Cr27Al7Mo2, with a surface working temperature up to 1400°C. The maximum short-term working temperature of electric heating radiant tubes using this material is 1250°C. The support frames are made of corundum ceramics. The outer protective sleeve is a cold-drawn seamless thin-walled heat-resistant steel tube, made of Fe-Ni-Cr-Al-Re alloy. This material has ultra-high oxidation resistance, capable of long-term operation at 1300°C in an oxidizing atmosphere and short-term oxidation resistance at 1360°C. It is suitable for operation in high-temperature, low-oxygen partial pressure environments and environments containing S and C. The electric heating radiant tubes designed and manufactured by our company are available for high, medium, and low-temperature furnaces as well as special atmosphere furnaces, with various specifications to choose from. The outer sleeve is made of seamless high-temperature alloy tubes, plate-coiled tubes, centrifugal cast tubes, non-metallic special carburization-resistant sleeves, etc. Considering that when radiant tube heating elements are used in various atmospheres and harsh cyclic conditions, general resistance alloys may not be suitable. Our company's researchers have developed a new resistance alloy material specifically for radiant tubes. This material has stable performance, high resistivity, low temperature coefficient, and is suitable for various radiant tube heating elements, replacing expensive imported materials with unique performance characteristics.
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
