How to prevent electrostatic hazards in industrial production
Anti-static experts pointed out: To prevent static electricity, first of all, try not to generate static electricity; the generated static electricity should be limited as much as possible so that it is not dangerous. Secondly, the generated charge is leaked or neutralized as soon as possible, thereby eliminating the large accumulation of charge. The following are common measures we often take to prevent electrostatic hazards in industrial production:
1. Reduce friction and electrification
At present, all countries in the world have no unified standards for flow control.
In short, when determining the flow rate, not only the inner diameter of the pipeline should be considered, but also the influence of various factors such as the nature of the fluid, the composition and amount of impurities contained, and the material of the pipeline. .
Even if the flammable liquid flowing in the pipeline has a higher average charge density, it usually does not show a higher voltage due to the larger capacitance in the pipeline, and it does not cause combustion and explosion due to the absence of air in the pipeline. . In this case, although static electricity will not cause danger to the inside of the pipeline, its serious harm is mainly concentrated at the outlet of the pipeline, and attention must be paid.
2. Static grounding
The role of static grounding is to release the charge that may accumulate on the conductor, make the conductor equipotential with the earth, and make the potential difference between the conductors zero.
3. Reduce resistivity
When the resistivity of a substance is less than 106Ω.cm, the accumulation of static charge can be prevented. Methods to reduce resistivity: A. Add conductive fillers; B. Use antistatic agents.
4. Increase air humidity
When the relative humidity of the air is higher than 65-70%, a very thin water film is usually formed on the surface of the object. The water film can dissolve CO 2 in the air, which greatly reduces the surface resistivity and is not easy to accumulate static charge. If the relative humidity of the surrounding air drops to 40% to 50%, static electricity will not dissipate easily and may form a high potential. A common method to increase air humidity is to spray water mist into the air. A rotary fan sprayer is usually used. However, this machine is not explosion-proof and must be blown in from the outside of the wall.
5. Air ionization method
Using a static eliminator to ionize oxygen and nitrogen ions in the air and turn the air into a conductor can effectively eliminate static charge on the surface of the object. Commonly used static eliminators are: (a) induction static eliminator; (b) high-voltage static eliminator.