Bolt electric heater is suitable for the installation and removal of bolt heating rods in steam turbines. Large bolt electric heaters for other pressure vessels can also be used as a reference.

The bolt heater is made by inserting electric heating wires into seamless metal pipes (carbon steel pipes, titanium pipes, stainless steel pipes, copper pipes), filling the gaps with magnesium oxide powder with good thermal conductivity and insulation properties, and then shrinking the pipes into various shapes required by users. It has a simple structure, high thermal efficiency, good mechanical strength, and I have good adaptability to harsh environments. The bolt heating rod can be used for heating various liquids and acid-base salts, and is also suitable for heating and melting low melting point metals. Due to its low price, easy use, convenient installation, and no pollution, it is widely used in various heating scenarios.

Test Methods and Acceptance Rules

After each electric heater is assembled, its insulation resistance shall not be less than 50M Ω measured with a 500V megohmmeter at room temperature. It shall also undergo a 1500V withstand voltage test for 1 minute without breakdown or flashing. Then, heat the electric heater in the air at the rated working voltage for 2-3 minutes without overheating, and the insulation resistance should not be lower than 0.5M Ω. The leakage current per kilowatt should not exceed 0.5mA. Check its power to see if it meets the ordering requirements (deviation ± 5%). After the test, check if all parts of the electric heater are intact.