Explosion-proof products generally have the following marks on the shell, the specific meanings are as follows:
Ex d II C T6 or Ex ia II C T6
1 234 5 1 234 5
1Ex----CQST certification mark
2d----Flameproof type: means that the instrument housing can withstand the internal explosion of the flammable mixture that has entered the inside of the enclosure without being damaged, and does not ignite through one or more of the interfaces and holes on the enclosure. Externally explosive atmosphere of electrical equipment formed by gas or steam.
Ia----intrinsically safe type: refers to a circuit system in which the sparks and thermal effects generated under normal operation or specified fault conditions do not ignite the specified explosive mixture of instruments and equipment.
3 Electrical equipment that does not cause the surrounding explosive atmosphere to ignite under the specified conditions falls into two categories:
I—Coal mine, underground electrical equipment
II - Factory Electrical Equipment
4 Type II According to the maximum experimental safety clearance or minimum ignition current of explosive gas atmosphere, it is divided into ABC level III. The equipment marked IIB can be applied to the conditions of use of IIA equipment; the equipment marked IIC can be applied to the conditions of use of IIA and IIB.
5 Maximum surface temperature T6: 85°C. According to the maximum surface temperature of the equipment, it is divided into six groups of T1 to T6, which refers to the maximum temperature reached by any component of the electrical equipment that may cause the surrounding explosive atmosphere to ignite when the instrument is operating under the most unfavorable operating conditions within the specified range. Should be lower than the flammable temperature.
Temperature Group Auto-ignition Temperature T (°C) Common Explosive Gas Equipment Permissible Surface Temperature (°C)
T1 T≥450 Hydrogen, acrylonitrile and other 46 species 450
T2 450>T≥300 Acetylene, Ethylene and other 47 species 300
T3 300>T≥200 Gasoline, crotonaldehyde and other 36 species 200
T4 200>T≥135 Acetaldehyde, tetrafluoroethylene, 6 kinds 135
T5 135>T≥100 Carbon disulfide 100
T6 100>T≥85 Ethyl Nitrate and Ethyl Nitrite 85
Take Xi'an Instrument Factory 1151 series transmitter as an example, the 1151 explosion-proof transmitter is a variant of the 1151 base transmitter. Its working principle and basic structure are the same as the basic model. The main differences are:
1. The terminal base is made of arc resistant plastic.
2. Use a nut-type pull-in device at the outlet.
3. Explosion-proof structures and parts are strictly inspected and tested according to explosion-proof standards.
1151 series explosion-proof transmitter passed the national explosion-proof electrical product quality supervision and inspection center (CQST) certification, flameproof and intrinsically safe two. Flameproof and intrinsically safe instruments meet the requirements of GB3836.1-83 "General Requirements for Explosion-proof Electrical Equipment for Explosive Atmospheres".
Flameproof type: Conforms to GB3836.2-83 "Explosion-proof electrical equipment explosion-proof electrical equipment "d"" provisions, its mark is Ex dsIIBT5.
Intrinsically safe type: It conforms to GB3836.2-83 "Intrinsically safe electrical circuit and electrical equipment "i"" for explosion-proof electrical equipment. Its symbol is Ex iaIICT5. And equipped with the provisions of the explosion-proof safety barrier (Xi'an Instrument Factory I series ISB safety retainer).
When selecting a model, the model specification is the same as the base product. In addition, for the explosion-proof type, the word Da is added. For the intrinsic safety type, the word Fa should be added. The application examples are as follows:
Base transmitter: DP4E22M1B1
Flameproof transmitter: DP4E22M1B1Da
Intrinsically safe transmitter: DP4E22M1B1Fa