What are the applications of static electricity that can turn waste into treasure?

It removes the tiny dust floating in the gas by electric method, the dust collecting electrode is grounded, and a DC voltage (-40 ~-200 kV) is applied to the discharging electrode to form a corona discharge. Dust-containing gas enters the discharge area from below the dust collecting electrode, and the dust will be charged with negative polarity. The negatively charged dust is adsorbed by the dust collecting electrode under the action of electric field, thus removing the dust in the airflow. In addition, when the discharge electrode is negative, the discharge voltage between the electrodes is higher than that when the discharge electrode is positive, so higher electric field intensity can be used. However, for small dust collectors for indoor air purification, in order not to produce harmful ozone, positive corona discharge is usually used. In recent years, efficient and economical electrostatic precipitator has been developed and applied. For example, the widespread installation of electrostatic precipitator in thermal power plants has made outstanding contributions to preventing air pollution.

(2) Electrostatic spraying

Using the principle of electric dust collection, it can spray efficiently. For example, if the coating is micronized and negatively charged, and the coated metal object is grounded, the ejected particles will move along the power line, so that the coating can be firmly attached to the surface of the object. Electrostatic coating has the following advantages: ① Less paint waste; ② It can be sprayed evenly and firmly; ③ It can be used for mass production of assembly lines and conveyor belts, and is widely used for spraying automobiles, household appliances and motors.

(3) Electrostatic photography

Electrostatic photography uses static electricity to record images, and there are various methods. The following is a method: first, put the metal plate with selenium film evaporated in a dark room and make it positively charged by corona discharge. Then exposed, a part of the selenium film irradiated by light will lose its positive charge. The negatively charged colorant (colored ions) will be sprinkled on the selenium film, and the remaining positively charged part of the selenium film will be attached with the colorant. The positively charged paper will be attached to this surface, copied to the pattern of the colorant, and heated to fix the colorant. Electrostatic photography, also known as electronic photography, is widely used in copiers and laser printers.

(4) electrostatic separation

Using electrostatic force to separate components from two particle mixtures with different conductivity is called electrostatic separation. For example, the mixed particles are placed on a metal plate, the particles are charged by corona discharge, and then the metal plate is tilted. At this time, because the particles with good conductivity lose more charge, the adhesion between them and the metal plate decreases, so that they can quickly slide off the metal plate, so that particle sorting can be carried out, such as electrostatic seed sorting used in agricultural production. Electrostatic separation has been applied to ore separation. Removal of foreign matter and separation of tea in food processing.

(5) the generation of 5)DC high voltage

Van der Graf electrostatic generator generates DC high voltage by charging the high voltage ball with corona discharge. It can do insulation inspection tests such as leakage current test, and is widely used in power equipment manufacturers and power systems.

(6) High voltage measurement

Electrostatic voltmeter and pulse voltage recorder are devices that use electrostatic phenomena to measure high voltage, which are widely used in electric power high voltage test and other fields.

(7) Ignition of fuel gas

Gas water heaters and gas stoves can be ignited by tiny current discharge, and the peak voltage of discharge pulse is tens of thousands of volts (discharge energy is about 1mJ). Automobile ignition also uses tiny current discharge to make the gas in the engine cylinder explode and gain power. When the gas is ignited, the peak pulse voltage is 10 ~ 100 kV.