Classification method of explosion-proof grade of electric heater

Classification method of explosion-proof grade of electric heater

First of all, explosion-proof electric heaters are divided into two categories: Category I is electrical equipment used in coal mines; II is electrical equipment used in places other than mines. Class II electrical equipment is divided into three categories: IIA, IIB, and IIC.
Secondly, to know the classification of explosion-proof grades, you must first know the grouping of explosive gas mixtures according to ignition temperature: the groups are indicated by T1.T2.T3.T4.T5.T6, the ignition temperature is indicated by t (℃), and the T1 group In addition, the ignition temperature is: 450℃＜t; T2 is: 300℃＜t≤450℃; T3 is: 200℃＜t≤300℃; T4 is: 135℃＜t≤200℃; T5 is: 100℃＜ t≤135℃; T6 is: 85℃＜t≤100℃.
Once again, we must know the explosion-proof type of explosion-proof electrical, the types are divided into: flameproof type, symbolized as d; increased safety type, symbolized as: e; positive pressure type, symbolized as P; intrinsically safe type, symbolized as i; and: Oil-filled, sand-filled, encapsulated, etc.
After knowing these points, I have a good understanding of the classification of explosion-proof grades. Explosion-proof electrical equipment is distinguished according to the type of equipment used; the temperature group of explosive gas mixtures; and the type of explosion-proof electrical equipment. For example, the symbol for explosion-proof is dIIBT4 means that the type of explosion-proof electrical products is explosion-proof, which is the IIB class (category) used in Class II places, and the ignition temperature of explosive gases is T4.

Precautions for electric heater thermocouple

1. The electromotive force of a thermocouple is the difference between the temperature functions of the two ends of the thermocouple, not a function of the temperature difference between the two ends of the thermocouple; 2. The size of the electromotive force generated by the thermocouple, when the thermocouple data is uniform, and the length of the thermocouple The diameter has nothing to do with the composition of the thermocouple and the temperature difference between the two ends; 3. When the composition of the two thermocouple wires of the thermocouple is determined, the electromotive force of the thermocouple is only related to the temperature difference of the thermocouple; if the cold end of the thermocouple is The temperature must be maintained. The electromotive force of the thermocouple is only a single value function of the temperature at the working end.

www.superbheater.com