1. The principle of electric heat tracing
After the heating belt is powered on, the current flows from one core to another core through the conductive PTC material to form a loop. The electrical energy heats up the conductive material, and its resistance increases immediately. When the temperature of the core strip rises to a certain value, the resistance is so large that it almost blocks the current, and its temperature does not increase. At the same time, the electric strip is heated to the lower temperature. System heat transfer. The power of the electric heating belt is mainly controlled by the heat transfer process, and the output power is automatically adjusted with the temperature of the heated system, while the traditional constant power heater does not have this function.
2. Installation precautions for electric heat tracing
1）When laying, do not discount, do not bear excessive pulling force, and prohibit impact hammering, so as to avoid short circuit after damage to the insulation. During installation, no welding, hoisting and other operations are carried out above the installation site to prevent the welding slag from splashing onto the heating tape and damaging the insulating layer. Make sure that the pipes or equipment to be traced have been leak tested and cleaned, and that the surfaces are free of thorns and sharp edges have been polished and smoothed.
2）When laying by winding, do not bend or fold the cable beyond the minimum bending radius, which may cause breakdown of the local molecular structure and cause fire.
3）The cable should be close to the surface of the pipe to facilitate heat dissipation, and the cable should be fixed with aluminum foil tape. The method is: first remove the oil stains and water in the way of the cable, fix the heating cable with the fixing tape, then lay the cover with the aluminum foil tape, and finally wipe and press the cable with a cloth to make the cable flat and stick on the surface of the pipe.
4）The construction of the thermal insulation layer and the waterproof layer must be done after the cable is installed and debugged, and the thermal insulation material must be dry. The wet thermal insulation material not only affects the thermal insulation effect, but also may corrode the ordinary heating cable and shorten the service life. After the thermal insulation material is installed, the waterproof layer must be wrapped immediately, otherwise the thermal insulation performance will be reduced and the normal operation of the heat tracing system will be affected.
5）The installation length of the cable should not exceed its “maximum allowable length”, and the maximum allowable length varies with different models.
6）When the shielded cable is connected, the electric heat tracing system shall not only have reliable grounding protection for the medium pipeline system, but also shall connect the braided layer together and install reliable grounding, and the conductive wire core at the end of the cable shall not collide with the shielded network.
7）The end of the cable is sealed with a terminal box, and two parallel wires cannot be connected to avoid short circuit.
8）The junction box must be firmly fixed on the pipe wall to avoid short circuit and fire.
9）The installation cable should be equipped with an over-dissolving protection device. Reliable over-dissolving protection measures must be set in the circuit. A fuse should be set for each heat tracing cable insulation system, so that the power distribution system has overload, short circuit and leakage protection functions.
10）After the electric heat tracing system is installed, the electrical test must be carried out one by one: check the insulation resistance of the system with a 500V ohmmeter, and the resistance between the core of the cable and the ground wire or the neutral wire should not be less than 5MΩ.
Jiangsu Weineng Electric Co.,Ltd is profession manufacturer of various types of industrial electric heater, everything is customized in our factory, could you please kindly share your detailed requirements, then we can check in details and make the design for you.
Contact: Lorena
Email: inter-market@wnheater.com
Mobile: 0086 153 6641 6606 (Wechat/Whatsapp ID)
Post time: Apr-11-2022