The most common reason for termination heating element is contamination. During cycles of warming and cooling, sheath heater expands and contracts allowing impurities to enter the material. This can cause damage to the mantle and penetration of electro material in the heater. Therefore, it is important to keep the organic and other conductive materials away from the heater.
The ends of the heating elements should be protected from high temperature, as well as against mechanical damage if the heater is mounted on the movable part of the machine. Negrejna zone heaters will greatly protect the contact connections from overheating.
If it is provided that the heating element is placed in a groove or mold, do so to leave as little free space to be more efficient heat transfer and thus reduce overheating.
It is always advisable to ground the equipment in which it is embedded heater to reduce the chance of damage to the machine and the violation of workers.
Temperature cycles a very unfavorable influence on the durability of the heater, particularly those which allow for full expansion and contraction of the resistance wire in a rapid cycle of 1 min, and the like. This causes severe stress and oxidation resistance wire in the heater.
The choice of materials mantle should be compatible with the temperature and the desired Watt load. Carbon steel and aluminum are sufficient if the temperature does not exceed a few hundred degrees, but as the temperature rises, so does the choice of sheath pipe heating element decreases. For higher temperatures must be used stainless steel. As temperatures rise, so we must reduce the watt load, in order to prevent the resistance wire oxidizes and prematurely fail.
Heaters immersed in the liquid to be set up to ensure maximum convection. The heating element should not be set so that it causes excessive collection of lime or other material around them, or that restricts the flow of fluid around. Heater must be submerged at all times, not to remain without fluid and can not be set in a way that will cause partial boiling and trapped pockets of steam.
Scale, cooking oil and other materials that accumulate on the surface of the heater, reduces the efficiency of heat transfer, causing the heating element works at high temperatures, and this situation shortens the life of the heater. To prevent this situation, it is necessary to periodically clean the heating element of scale, oil and other impurities.
