Explosion-proof refers to preventing explosions. We all know that no matter it is chemical crude oil, coal mining, warehouses, etc., there are places where fire cannot be seen. Once it encounters fire, it will explode, causing huge harm to human life and property. , Usually we will classify explosion-proof according to relevant standards to make corresponding explosion-proof strategy, then what is the classification standard of explosion-proof classification? In this article, the editor of Xianji.com will introduce the classification standards and explosion-proof types of explosion-proof grades, and the differences between explosion-proof grades ct6, ct4 and bt4. Let's take a look.

Explosion-proof classification standard

my country divides explosion-proof electrical appliances into three categories:

Class I explosion-proof electrical is suitable for underground coal mines;

Class II explosion-proof electrical is suitable for explosive gas environment;

Class III explosion-proof electrical is suitable for explosive dust environment.

Most of the explosion-proof electrical equipment used by petrochemical enterprises is Class II explosion-proof electrical equipment.

When explosion-proof electrical equipment operates in an explosion-hazardous place, it has the performance of not igniting explosive substances, and the maximum temperature of its surface shall not exceed the ignition temperature of hazardous substances in the workplace.

① Flameproof type (d)

This kind of electrical equipment has a flameproof enclosure, even if an explosive mixture enters and causes an explosion, it will not cause an explosion of an external explosive mixture. It is designed according to the principle of the maximum non-explosion gap, with a solid shell, can withstand 1.5 times the actual explosion pressure without deformation; the temperature of the equipment can not ignite explosive mixtures when it is running continuously. This type of equipment has high safety performance and can be used in hazardous locations at all levels outside Zone 0.

②Increased safety type (e)

Also known as explosion-proof safety type, under normal operating conditions, it will not produce sparks that ignite explosive mixtures or reach dangerous temperatures, suitable for Class 1 and Class 2 hazardous areas.

③Intrinsically safe (i)

Sparks or thermal effects in normal operation or under standard test conditions will not ignite explosive mixtures. Intrinsically safe equipment is divided into grade ia and grade ib according to its safety degree: grade ia - mixture of explosive gases cannot be ignited during normal operation and one fault and two faults, mainly used in zone 0; grade ib - in Mixtures of explosive gases that cannot be ignited during normal operation and a malfunction, mainly for use in zone 1.

④Positive pressure type (p)

This kind of electrical equipment has a protective casing, and the casing is filled with protective gas (inert gas), and its pressure is higher than the pressure of the surrounding explosive gas mixture, so as to prevent the external explosive gas mixture from entering the casing and causing explosion.

⑤Oil-filled type (o)

Immerse parts that may generate sparks, arcs or dangerous temperatures in oil to extinguish arcs, insulate, dissipate heat, and prevent corrosion, so that explosive mixtures above the fuel surface and around the casing cannot be ignited.

⑥ Sand filling type (q)

The shell is filled with fine sand granular material, so that under the specified conditions of use, the arc generated in the shell, the spread of flames, and the overheating temperature of the shell wall or the surface of the granular material cannot ignite the surrounding explosive mixture. Suitable for use in Class 1 and Class 2 hazardous areas.

⑦Non-sparking type (n)

Under normal operating conditions, there is no arcing or sparking, no hot surfaces or hot spots that could ignite surrounding explosive compounds, and generally no igniting failures occur. It is mainly used in Class 2 hazardous areas and has a wide range of applications.

⑧Explosion-proof special type (s)

Explosion-proof electrical equipment whose explosion-proof measures are outside the provisions of the national standard, especially explosion-proof electrical equipment designed for Zone 0 or Zone 1, must be approved by the relevant competent authorities and tested by the designated appraisal unit.