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Requirements for explosion-proof cable explosion-proof electrical appliances used in explosive dust environment

by:AAA     2020-03-21
At present, with the rapid development of industrialization in our country, dust explosions occur many times in the production process of enterprises, which affect the property losses of enterprises and cause unsafe factors for enterprises. Enterprises must raise their awareness of safety, only in this way can unnecessary losses of enterprises be reduced. How much harm will dust explosion do? How can we prevent it? First, the main hazards of dust explosion, for the environment where explosive dust, combustible conductive dust, combustible non-conductive dust and explosive dust mixture formed by combustible fibers and air appear or may appear during production, processing, treatment, transportation or storage, it is an explosive dust environment. Dust in explosive dust environment should be divided into the following four types. (1) Explosive Dust: this kind of dust can catch fire even in an environment with little oxygen in the air, and can produce violent explosion in a suspended state, such as magnesium, aluminum, aluminum bronze and other dust. (2) Combustible conductive dust: conductive dust burning with oxygen in the air, such as graphite, carbon black, coke, coal, iron, zinc, titanium and other dust. (3) Combustible non-conductive dust: non-conductive dust burning due to thermal reaction with oxygen in the air, such as polyethylene, phenol resin, wheat, corn, sugar, dye, cocoa, wood, rice bran, sulfur and other dust. (4) Combustible fiber: a fiber that burns with the oxygen in the air, such as cotton fiber, hemp fiber, silk fiber, wool fiber, wood fiber, man-made fiber, etc. Second, dust explosion is prone to secondary explosion. The first explosive air wave blows up the dust deposited on the equipment or the ground. In a short time after the explosion, the explosion center will form a negative pressure, and the surrounding fresh air will be filled in from outside to inside, the so-called 'return wind' is formed, which is mixed with the raised dust and causes the second explosion under the ignition of the residual fire of the first explosion. In the second explosion, the dust concentration is generally much higher than that in the first explosion, so the power of the second explosion is much larger than that in the first explosion. It will affect the explosive combustion of electrical and equipment circuit control systems, and the generation of different toxic gases will often cause a large number of casualties after the explosion, which must be paid full attention. Three, how to prevent dust explosion (1)Is to reduce the concentration of dust in the air. Adopt equipment with good sealing performance to minimize dust flying and escaping, and at the same time install effective ventilation and dust removal equipment to strengthen cleaning work. (2)Is to control the indoor temperature. (3)It is to improve the equipment and control the fire source. For places with dust explosion hazard, fourth, dust-producing enterprises must choose national quality standards for explosion-proof electrical, explosion-proof motor, explosion-proof switch, explosion-proof light, explosion-proof axial flow fan, etc. Intrinsically safe explosion-proof cable is more important, bi Guohua, manager of Tianjin cable General Factory, reminded customers that explosion-proof IA grade must be adopted when using intrinsically safe explosion-proof cables. ( Explosion-proof control cable, explosion-proof signal cable, explosion-proof computer cable, explosion-proof coaxial cable) Under normal working conditions, when there is one or two faults in the explosion-proof Cable, the explosive gas mixture cannot be ignited. In Type IA explosion-proof Cable, the working current is limited to less than 100mA, which is suitable for chemical industry, dust enterprises, etc. Information Source: Tianjin cable plant a branch manager, Guohua advisory hotline 0316- 5960003/5962582
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