Electrical grade magnesium oxide powder is the main filling material in electric heating tubes and has good thermal conductivity, insulation and high temperature resistance. The following matters should be noted during use:
Choose the right magnesium oxide powder
Electrical-grade magnesium oxide powder can be divided into ordinary type, low-temperature moisture-proof type, medium-temperature moisture-proof type and high-temperature type according to its use. When selecting magnesium oxide powder, the appropriate type should be selected based on the operating temperature and working environment of the electric heating tube.
Pay attention to the hygroscopicity of magnesium oxide powder
Magnesium oxide powder is a highly hygroscopic material. If left in the air for too long, it will absorb moisture and affect its thermal conductivity and insulation. Therefore, it should be dried before use, and the magnesium oxide powder should be heated to about 800°C to completely dehydrate it.
Avoid contact between magnesium oxide powder and acid
When magnesium oxide powder comes in contact with acid, it will react to form magnesium hydroxide, which affects its thermal conductivity and insulation. Therefore, contact with acid should be avoided when using electric heating tubes.
Pay attention to the bending of the electric heating tube
The electric heating tube may need to be bent during use, and the bending radius should be greater than 2 times the tube diameter. For longer electric heating pipes, they should be annealed before bending.
Specifically, for stainless steel components with relatively long tubes (such as 4 to 6 meters), they must be annealed at a high temperature of 900°C before bending. In this case, the resistance wire should be made of nickel-chromium wire instead of iron-chromium wire as much as possible. Wire, because aluminum (Al) is particularly easy to steal oxygen from MgO powder at 900°C (aluminum has a strong affinity with oxygen). As a result, part of the magnesium oxide turns black, the insulation resistance decreases, and the voltage resistance or thermal performance is poor.
In addition, the following matters should be paid attention to when using electric heating tubes:
Electric heating pipes should be installed in a well-ventilated area to avoid the generation of harmful gases.
Electric heating tubes should be inspected regularly and replaced in time if any abnormalities are found.
Correct use of electrical grade magnesium oxide powder can extend the service life of electric heating tubes and improve safety.