Static electricity is an invisible fire "killer"
The concept of static electricity and electrostatic hazards:
Static electricity is relatively static in the macroscopic range, and static electricity is a positive or negative charge that temporarily loses equilibrium. In the case of dangerous static electricity generated and accumulated, if there is an explosive mixture in the space, it may cause a fire and explosion due to static sparks, whether it is combustible solids, powder materials or gas materials; whether it is machine operation or manual operation, An electrostatic fire or explosion is caused by static electricity.
In terms of process classification, the solid material has a large area of friction, and the solid materials are in contact with each other under pressure and then separated, and the solid material is extruded, and the friction occurs between the pipe wall and the filter wall, and the solid material. The process of crushing, grinding, stirring, etc. can cause dangerous static buildup. Processes such as filtration, sieving, pneumatic conveying, agitation, spraying, and transport of powder materials may also cause dangerous static buildup. Liquid materials can generate dangerous static buildup during high-speed flow, filtration, agitation, spraying, spraying, scouring, splashing, pouring, and even precipitation. Flammable liquid vapors and flammable gases can also pose dangerous electrostatic buildup when they are entrained in solids or liquids, when they are ejected at high speeds from slits or valves or at high speeds in the pipe.
In addition, people wearing synthetic chemical fiber garments may have dangerous static buildup during flight. Therefore, many fires and explosions are caused by static electricity accumulation.
It is well known that friction can generate static electricity. Generally, friction includes complex processes of contact, separation, breaking, piezoelectric, thermoelectric, etc., and the most important one is the contact-separation process. The contact/separation theory has been widely used to explain the generation of solid static electricity. Liquid static electricity is different from the generation of vapor and gas static electricity. Liquid statics are accompanied by electroosmosis, batteries, and electrolysis effects, as well as the presence of an electric double layer at the interface between the solid and the liquid. The vapor and gas static electricity is essentially the electricity contained in the solid impurities or liquid impurities contained therein. Although there are many ways to generate static electricity, the motor is not the same, but one thing is the same, that is, the static electricity generation is not related to electricity.
Electrostatic voltages sometimes reach tens of thousands of volts or even hundreds of thousands of volts, and the energy required to generate high-voltage static electricity is extremely small and limited. The direct cause of electrostatic fires and explosions is electrostatic discharge sparks.
Measures for static electricity prevention:
Static electricity has its special characteristics. When strengthening prevention, it should correctly understand the static temper. There are four conditions for static or fire:
1. The space has an explosive mixture present;
Second, there are process conditions and operating procedures for generating static electricity;
3. The accumulation of static electricity reaches or exceeds a considerable extent, causing the local electric field between the dielectrics to be broken down;
4. The electrostatic discharge spark energy reaches the minimum point energy of the explosive mixture. These four conditions are indispensable for fire and explosion.
So anti-static needs to be done:
First, eliminate the danger of explosion in the surrounding environment. Ventilation conditions are usually used to reduce the concentration of the explosive mixture or to fill in an inert gas to reduce the oxygen content. At the same time, explosion-proof measures should be taken to replace the combustible medium with a non-combustible medium. This is an indirect preventive measure.
Second, the material can be appropriately selected, the manufacturing process equipment can be reformed, and the friction speed or relative motion speed of the production tool can be reduced, impurities and additional static electricity can be eliminated, and static electricity generation can be suppressed. This is a direct measure to prevent static fires.
Third, limit the accumulation of static electricity through leakage and neutralization. Such as grounding, humidification, antistatic measures, static eliminators, etc. In order to prevent static electricity from becoming disaster-free, in addition to taking the above-mentioned precautionary measures, it is also necessary to establish strict process rules and regulations, and simultaneously adopt electrostatic static measurement, monitoring and other technologies to truly make the danger of electrostatic disasters in the production environment and living places. Go to your heart and get preventive.
Fourth, the on-site operators wear anti-static clothing, you can choose anti-static joint work clothing, anti-static split suit, anti-static big coat, and so on according to different needs.