Most petrochemical companies stipulate that employees cannot use mobile phones in the factory because mobile phones are a kind of radio communication tools. Radio waves emitted by radio transmitters (radio frequency electromagnetic radiation) can induce radio frequency currents from antennas that accept radios. When the RF current circulates between the metal conductors, it will generate RF sparks if it is rusted or poorly contacted. The radio frequency spark generated by the mobile phone encounters the mixture gas in the chemical plant area and is easily caused to explode, resulting in disasters. In response to the above situation, explosion-proof mobile phones came into being. It is no different from the shape of an ordinary mobile phone, but it is very different from the normal model in terms of materials and physical properties. Manufacturers use a variety of explosion-proof technologies, such as intrinsically safe circuits, limit the maximum surface temperature of the enclosure, use a "dust-tight" or "dust-proof" enclosure to limit dust entry, etc., to prevent the explosive mixture from being ignited, making the explosion-proof mobile phone in the chemical plant. It can be used safely in flammable and explosive environments. We know what an explosion-proof phone is, and then companies need to know how to choose an explosion-proof phone that suits their business. Mainly from two aspects: explosion-proof signs and explosion-proof mobile phone types.
One. Explosion-proof mark
According to the requirements of GB 3836 for explosion-proof electrical equipment, the explosion-proof markings of explosion-proof electrical equipment include: explosion-proof type + equipment category + (gas group) + temperature group
Explosion-proof type
According to the explosion-proof measures taken, the explosion-proof electrical equipment can be divided into explosion-proof type, increased safety type, intrinsically safe type, positive pressure type, oil immersion type, sand filling type, encapsulation type, n type, special type, dust explosion-proof type. Wait. Their identification is shown in the table below. 2. Most of the petrochemical enterprises in the equipment category belong to the flammable and explosive mixed gas environment. The explosion-proof type of explosion-proof electrical equipment generally requires intrinsic safety type to meet.
Electrical equipment for explosive gas environments is divided into:
Class I: Electrical equipment used in coal mines;
Class II: Electrical equipment for use in other explosive atmospheres other than coal mines.
Class II flameproof "d" and intrinsically safe "i" electrical equipment are further classified into IIA, IIB, and IIC.
Electrical equipment for flammable dust environment is divided into:
Type A dusttight equipment; Type B dusttight equipment; Type A dustproof equipment; Type B dustproof equipment.
Therefore, the equipment category of explosion-proof mobile phones in petrochemical enterprises is generally intrinsically safe type IIA, IIB, and IIC. The IIC class on the market can meet most chemical plant requirements. 3. Gas group
The explosive capacity of an explosive gas mixture indicates the degree of explosion hazard. The greater the explosive capacity of an explosive mixture, the higher the risk. The explosive capacity of an explosive mixture can be expressed by the maximum test safety clearance. At the same time, the difficulty of igniting explosive gases, liquid vapors, and mists also indicates the degree of explosion hazard, which is expressed by the Too small ignition current ratio. Class II explosion-proof electrical equipment or intrinsically safe electrical equipment are further classified into categories IIA, IIB and IIC according to their maximum test safety clearance or Too small ignition current ratio applicable to explosive gas mixtures. 4. Temperature group
The ignition temperature of an explosive gas mixture is the temperature limit at which it can be ignited. The electrical equipment is divided into T1~T6 groups according to its highest surface temperature, so that the highest surface temperature of the corresponding T1~T6 group electrical equipment cannot exceed the allowable value of the corresponding temperature group. The relationship between the temperature group, the surface temperature of the equipment, and the ignition temperature of the flammable gas or vapor is shown in the table below. Combined with the above, what kind of explosion-proof mobile phone should be used by petrochemical enterprises, the answer is clear at a glance.