Explosion-proof electrical equipment according to standard GB 3836 requirements, explosion-proof electrical equipment of explosion-proof marks include:

Explosion-proof type + + equipment category (gas group) + temperature classes

1 the explosion-proof type

According to the explosion protection measures, can be divided flameproof explosion-proof electrical equipment, increased safety, intrinsically safe, positive pressure,

Oil-immersed type, sand mold filling, encapsulation type, n type, special type, dust explosion-proof type, etc. The stickers as shown in table 1.

Explosion-proof basic types in table 1

Explosion-proof type

Explosion-proof type of logo

Explosion-proof type

Explosion-proof type of logo

flameproof

The Ex d

Sand mold filling

The Ex q

Increased safety type

The Ex e

Encapsulation type

The Ex m

Positive pressure type

The Ex p

n

The Ex n

The Ann model

E x ia

The Ex ib

Special type

The Ex s

Oil-immersed type

The Ex o

Dust explosion proof

DIP A

DIP B

2 equipment category

Electrical equipments used in explosive gas environment is divided into:

Class I: the coal mine electrical equipment;

Class II: in addition to the coal mine of other electrical equipments used in explosive gas environment.

Class II flameproof "d" and "I" intrinsically safe electrical equipment is divided into type IIA, IIB, IIC and class.

Combustible dust environment with electrical equipment is divided into:

Type A dust tight equipment; B type dust tight equipment;

Type A dustproof equipment; B type dust equipment.

3 gas group

Explosive gas mixture detonating capability, marks its explosion hazard degree of high and low, an explosive mixture of detonating capacity is more big, the higher risk. Explosive mixture detonating capacity available maximum test security said on the sidelines. At the same time, the wild fire, to the difficulty of the liquid vapor, the mist was lit also marks its explosion hazard degree of discretion, it USES the minimum ignition current than said. Class II flameproof electrical equipment or intrinsically safe electrical equipment, according to the applicable to the biggest test of explosive gas mixture security clearance or minimum ignition current ratio, further divided into type IIA, IIB, IIC class.

As shown in table 2.

Table 2 biggest test of explosive gas mixture groups with the security clearance or the relationship between the minimum ignition current ratio

Gas group

Biggest test security clearance MESG (mm)

Minimum ignition current than MICR

Type IIA

MESG 0.9 or higher

MICR > 0.8

IIB

0.9 > MESG > 0.5

0.8 MICR acuity 0.45 or higher

IIC

0.5 or greater MESG

0.45 > MICR

4 temperature classes

The ignition temperature of explosive gas mixture is the temperature limit value can be lit.

Electrical equipment according to its maximum surface temperature can be divided into T1 ~ T6 group, makes the corresponding T1 ~ T6 group of electrical equipment of the highest surface temperature cannot exceed the corresponding temperature classes permitted. Temperature classes, the equipment surface temperature and the degree of the ignition temperature of combustible gas or vapour of the relationship between as shown in table 3.

Table 3, the equipment surface temperature and temperature classes the relationship between the ignition temperature of flammable gas or vapor

IEC/EN/GB 3836 temperature level

Equipment of the highest surface temperature of T (℃)

The lighting temperature of combustible material (℃)

T1

450

T > 450

T2

300

450 p T > 300

T3

200

300 p T > 200

T4

135

200 p T > 135

T5

100

135 p T > 100

T6

85

100 p T > 8

5 explosion-proof marks were illustrated

In order to further clear the representation method of explosion-proof marks, for examples of gas explosion proof electrical equipment as follows:

As for the I type flameproof electrical equipment: explosion-proof marks for ExdI

As for class II flameproof electrical equipment, gas group for group B, temperature classes for T3, explosion-proof marks as: ExdIIBT3.

Such as electrical equipment for class II intrinsically safe ia, gas group for group A, T5 temperature classes, explosion-proof marks as: ExiaIIA T5.

For special type: type I ExsI.

For use in mine besides biogas, under normal circumstances for group B, and class II gas group for inflammable gas T3 body temperature classes is the flameproof electrical apparatus, explosion-proof marks as: ExdI/IIBT3.

In addition, for the following special circumstances, explosion-proof marks content can be appropriately adjusted:

(1) if the electrical equipment using more than one compound type, explosion-proof type should be marked first subject, after noting other explosion-proof type. Such as: class II group B subject type flameproof and increased safety box T4 motor, explosion-proof marks for: its ExdeIIBT4. [JP3 〗

(2) if only allowed to use in a combustible gas or steam environment electrical equipment, the logo can use the gas or vapor chemical formula or name said, at this time, but don't have to indicate the category and the temperature of the gas group. Such as: class II for ammonia environment of flameproof electrical equipment, explosion-proof marks for: ExdII (NH 3) or ExdII (ammonia).

In turn, the use of table 2, manufacturer can be determined in accordance with the explosion-proof electrical products using the environment the temperature of the product categories, according to the design of electrical equipment temperature classes is the shell surface temperature or internal temperature. Explosion-proof electrical equipment users can according to the place that may occur in the types of explosive gas or steam, convenient to choose the temperature of the explosion-proof electrical products category. Known environment, for example, to save on isobutane ignition temperature (460 ℃), can choose the T1 group explosion-proof electrical products; If the environment of butane and ether ignition temperature (160 ℃), must choose the T4 group explosion-proof electrical products.

For dust explosion-proof electrical equipment:

Such as type A device can be used for 21 area, maximum surface temperature T A is 170 ℃, the explosion-proof marks for: DIP A21 TA170 ℃ or DIP A21TA, T 3;

Such as type B equipment, can be used in zone 21 in the highest surface temperature of T B is 200 ℃, the explosion-proof marks for: DIP B21 T B200 ℃ or DIP B21TB, T 3

6 set up the logo requirements

(1) local Settings should be in the main part of electrical equipment obvious signs;

(2) the logo must be considered under the possible chemical etching, still clear and durable. Such as marking the Ex, explosion-proof type, category, temperature classes available in relief or indented standard in the obvious place of shell,

Sign on the material of corrosion resistance of material should be adopted, such as bronze, brass or stainless steel.

7 on the international commonly used marker of explosion-proof electrical equipment, for example

Table 4

The international electrotechnical commission (IEC)

The Ex d [1] IIC T5

Among them:

The Ex - explosion-proof

D - (flameproof) protection way

[1], the Ann output device context

II - equipment category

C - gas group

T5 - [] temperature classes

CENELEC (European electrotechnical commission)

EEx d [1] IIC T5

Among them:

Logo EEx - Europe

D - (flameproof) protection way

[1], the Ann output device context

II - equipment category

C - gas group

T5 - temperature classes

US 505 (NEC) * (US)

Class I, Zone 1, A Ex d [1] IIC T5

Among them:

Class I - allow the category of the

Zone 1 - allows the use of places

A - the American national standards

The Ex - explosion-proof

D - (explosion-proof) protection way

[1] - this Ann

II - equipment category

C - gas group

T5 - temperature classes

US 500 (NEC) (United States)

Explosionproof with I.S. Outputs, Cl ɑ ss I, Division 1, Group A, B, C, D, T5

Among them:

Explosionproof

With I.S. Outputs - protective methods (optional) besides I S

Cl ɑ ss I - allows the category

Division 1 - allows the level (in addition to level 2, optional)

Groups A, B, C, D - allow gas group

T5 - temperature classes

* NEC electrical code for the United States, in 1996, the United States increased in the electrical code chapter 505, to I EC is generally used to with the international standard system for the dangerous sites coordinated division method. NEC 500 expressed as dangerous sites suitable for north American division system