1.EX: EX is the exclusive symbol of explosion-proof products, and all domestic explosion-proof products must be marked with this symbol;
2. The letter D stands for the explosion-proof type of the product, so there are many types of explosion-proof, such as D is flameproof, I is intrinsically safe, E is increased safety, and M is sealed.
3.Ⅱ; II indicates the classification of explosion-proof areas, * * * has zones I, II and III, and each zone has different requirements for products;
4.c； C means that flammable and explosive gas in hazardous environment is Class C gas (representing gas is 3 1% hydrogen), and there are three kinds of gases: A (representing gas is propane), B and C (representing gas is acetylene and 3 1% hydrogen);
5.T4: indicates the temperature grade of explosion-proof products. * * There are six grades, namely T 1≤450℃, T2≤300℃, T3≤200℃, T4≤ 135℃, T5≤ 100℃ and T6≤85℃.
To sum up, an explosion-proof mark is composed of temperature group (T) of explosion-proof equipment+explosion-proof area (zone 0, 1 zone 2)+use environment of explosion-proof equipment (zone I, zone II and zone III)+explosion-proof type, and then passes strict standard testing and certification, and finally obtains the explosion-proof certification certificate.
Explosion-proof electrical equipment (D): Electrical equipment that encloses the components that can ignite explosive mixture in a shell, which can withstand the explosive pressure of the internal explosive mixture and prevent it from spreading with the surrounding explosive mixture.
Electrical equipment with enhanced safety (E): Electrical equipment that does not generate sparks or dangerous temperatures to ignite explosive mixtures under normal operating conditions, and structural measures are taken to improve its safety to avoid ignition under normal and specified overload conditions.
Intrinsically safe electrical equipment (I): Electrical equipment that will not ignite explosive mixture due to sparks or thermal effects under normal operation or standard test conditions.
Spark-free electrical equipment (n): Electrical equipment that does not produce arc or spark under normal working conditions, nor does it produce high-temperature surfaces or hot spots that can ignite the surrounding explosive mixture, and generally has no ignition failure.
Special explosion-proof type: when electrical equipment or components adopt explosion-proof types not included in GB3836-20 10, the competent department shall formulate interim regulations. Send it to the Ministry of Labor and Personnel for filing, and dispose of it as "S" special electrical equipment after inspection by the designated appraisal unit.
Category, grade and temperature group of explosion-proof electrical equipment
According to the minimum ignition current ratio, gas and steam dangerous substances are divided into class IIA, class IIB and class IIC in China. The minimum ignition current ratio is ≤ 1.0, and > 0.8 is class IIA; ≤0.8, & gt0.45 is Class Ⅱ B; ≤0.45 is Class Ⅱ C. For example, ethane, ethylene and acetylene are classified as Class IIA, Class IIA and Class IIA respectively.
Class I: underground electrical equipment in coal mines;
Category II: All electrical equipment used in explosive gas environment except coal mine and underground.
Class Ⅱ can be divided into Class Ⅱ A, Class Ⅱ B and Class Ⅱ C, and the equipment marked with Class Ⅱ B can be suitable for the use conditions of Class Ⅱ A equipment; Ⅱ c can be used for Ⅱ a and Ⅱ b.
Category III: Electrical equipment in explosive dust environment except coal mine.
Class Ⅲ A: combustible fly ash; Class ⅲ b: non-conductive dust; Class ⅲ c: conductive dust.
The above content comprehensively analyzes the meaning of each symbol letter of explosion-proof grade D Ⅱ CT4, and I hope you like it.