The materials used for sealing (moisture-proof) electric heating tubes mainly include glass, epoxy resin, silicone oil, etc. Among them, the electric heating tube sealed with silicone oil will evaporate due to heating, and the insulation of the electric heating tube will decrease. The temperature resistance of epoxy resin materials is not high, and they cannot be used in high-temperature electric heating pipes such as barbecues and microwave ovens with high nozzle temperatures. Glass has high temperature resistance but high price, and is commonly used for sealing high-temperature pipes.

1. Medium and low temperature pipes can have no sealing;

2. Places with moisture must be sealed.

The inner core of the electric heating radiation tube is composed of resistance wires and ceramic support frames welded at the U-shaped axial end. There is no shielding between the inner core and the outer protective sleeve, which provides good heat dissipation. In an electric heating radiation tube with a rated working temperature of 1000 degrees, the material of the resistance wire is Cr20Ni80 or 0Cr21Al6Nb, and the surface working temperature can reach 1200 degrees. The maximum working temperature of the electric heating radiation tube using this material can reach 1000 degrees, and the support frame is a high aluminum ceramic component. The outer protective sleeve is a cold drawn seamless thin-walled heat-resistant steel pipe, made of 1Cr25Ni20Si2 or 1Cr25Ni35Si2. This material has good high-temperature oxidation resistance, high high-temperature creep strength, and certain anti carburizing performance. The design and material selection of this radiation tube have a high safety factor.

An electric heating radiation tube with a rated working temperature of 1200 degrees, the material of the resistance wire is 0Cr27Al7Mo2, and the surface working temperature can reach 1400 degrees. The maximum short-term working temperature of the electric heating radiation tube using this material is 1250 degrees, and the support frame is made of steel jade porcelain parts. The outer protective sleeve is a cold drawn seamless thin-walled heat-resistant steel pipe made of Fe Ni Cr Al Re alloy, which has ultra-high oxidation resistance. It can work for a long time at 1300 degrees Celsius in an oxidizing atmosphere and has short-term oxidation resistance at 1360 degrees Celsius. Suitable for working in high temperature, low oxygen partial pressure, and environments containing S and C.