What is the problem with uneven heating of electric heaters?

The heating principle of the electric heater is that the internal resistance wire passes current, and the resistance wire heats and conducts heat through the internal insulating magnesium oxide powder, thereby generating heat. Factors affecting uneven heating:

1. Improper selection of resistance wire. Resistance wire directly affects the effect of the electric heater during use. Non-standard resistance wire, it is difficult to distinguish good from bad by appearance. However, it can be found from the efficiency of use that if inferior materials are used to achieve the effect of conductive performance, some heat dissipation effects are good and some heat dissipation effects are poor. Improper design of resistance wire. The universal electric heater in the wire is designed in a spiral shape, that is a spring shape. If the ratio of the diameter of the core wire, the winding diameter D1, and the wire diameter D is D1/D > 8, the powder will produce sagging when the electric coil is densely packed with thin layers.

2. Resistance wire gap and uneven material hardness. The conductor resistance wire is a resistance wire with slender winding according to the design requirements. Try to ensure that the gap between the resistance wires is even, and when energizing, ensure that the objects on the tube are evenly heated. Otherwise, the density of regional temperatures will be higher than the density of small regions. Due to the uneven hardness of the resistance wire material, the spiral pitch after the wire is wound is uneven. This situation usually occurs in the drawing of electric heating wire using the well-type process. Uneven tension in the spiral heating wire winding also affects the unevenness of the spiral pitch.

3. Improper filling of magnesium oxide powder. The electric heater inside the filling is magnesium oxide powder. If it is filled manually, it will lead to filling and the internal tightness cannot be grasped. The heat of the part that is too tight will be slower, and the heat of the part that is too loose will hurry up.

4. The electric heater and powder-adding equipment are defective. If the amplitude of the powder equipment is unstable, the lifting speed of the guide rod is uneven, and the powder leaks quickly and slowly, etc. Even if all parameters are normal, magnesium oxide powder will be dense at the next thin level.

5. The electric tube process operation is inappropriate. When the lead rod is exposed, the amount of powder increases. If it does not meet the requirements, add an extension wire to the edge of the vibration side and the edge of the tube to extend the electric heating wire, or add pressure to the vibration side of the tube if it is too long. side. This will cause the local electric heating wire to be too thin or the local area to be too close to the electric heating coil and even cause a short circuit. Improper operation during the reduction process will also affect the uniformity of the heating wire distribution, resulting in uneven heating of the electric heater.

6. Environmental voltage caused by external use of electric heater: When the voltage used externally is different from the rated voltage, uneven heating of the internal resistance wire will occur. Service life: Electric heaters have a certain life span. After long-term use, the electric heater wires will become damaged, the internal resistance wires will age, the internal resistance wires will deform, and the internal components will age, which may also lead to uneven electric heaters. Combination of electric heaters: Use a combination of electric heaters. If the failure is evenly distributed, the heating effect will be different.