For example, there are electrostatic induction electrostatic vacuum cleaners, electrostatic spraying, electrostatic spinning, electrostatic flocking, electrostatic copying, electrostatic medical treatment, etc. For details, see:
Gases that use electrostatic induction and high-voltage electrostatic fields Discharge and other effects and principles enable a variety of processing techniques and processing equipment. It is widely used in electric power, machinery, light industry, textile, aerospace and high-tech fields.
Electrostatic precipitating and sorting Electrostatic precipitating uses the effect of electrostatic field to charge the dust particles suspended in the gas and be adsorbed, and separate the dust particles from the flue gas and remove them. This is the main aspect of electrostatic applications and can be used for flue gas dust removal in various factories.
Electrostatic spraying uses electrostatic adsorption to apply polymer coating particles to grounded metal objects, and then sends them into an oven to form a coating of uniform thickness. The corona discharge electrode charges paint particles with a diameter of 5 to 30 microns. Under the action of air transport and electrostatic force, the paint particles fly towards the object to be coated. The adsorption force between the charge of the particles and the induced charge on the object to be coated Make the paint adhere firmly to the object being coated. Generally, after 2 to 3 seconds, the coating can reach 40 to 50 microns thick.
Electrostatic spray painting is to charge the paint mist sprayed from the spray gun under the action of high-voltage electrostatic field. This charged paint mist is adsorbed to the surface of the workpiece with different charges and deposited into a uniform layer. Coating film. The paint liquid utilization rate of electrostatic spraying is very high, reaching 80-90%. Mainly used in automobile, machinery, household appliances and other industries.
Electrostatic sprayers and electrostatic powder sprayers that spray pesticides are equipped with electrostatic sprinkler heads. They use hundreds to thousands of volts of high-voltage DC power to energize the sprinkler heads to charge the liquid or powder particles, thereby preventing and controlling pesticides. The target induces charges of opposite polarity due to electrostatic induction, causing the liquid or powder particles to run towards the prevention target under the action of the electrostatic field. The use of electrostatic interaction can significantly improve the hit rate, reduce the loss of chemicals and environmental pollution, and spray chemicals onto the back of the target to enhance the control effect.
Electrospinning uses the force of the electrostatic field on the fibers during the spinning process to straighten, arrange and condense the fibers, and plays a balancing role when the free end strips are twisted. Spinning can be carried out continuously. It is a new spinning technology that belongs to the category of open-end spinning. The United States first conducted research in 1949. It is still in the theoretical discussion and experimental stage in the world and has not yet reached the scale of industrial production. China began research in 1958 and has now established a pilot workshop and can stably produce dozens of varieties. The electrospinning device is composed of four parts: a single fiber supply mechanism, an electrostatic field generator, a twister and a winding mechanism. The main process flow is drawing and moisture feeding, low-speed licker-in carding, air-flow stripping and conveying, directional arrangement in the electric field of a closed container and high-speed rotation to twist the yarn. The problem is that there are many yarn defects, and labor productivity and economic benefits cannot keep up with traditional spinning technology. But its advantages are high output, large forming, combining the three processes of roving, spun yarn and bobbin into one, and saving electricity. Especially when used in the production of core-spun slubs, colorful slubs and blends, the advantages of electrostatic spinning can be shown.
Electrostatic flocking uses the force of an electrostatic field to polarize the villi and arrange them along the direction of the electric field. At the same time, they are attracted to a base coated with adhesive to form villi products. The device consists of two parallel plate electrodes. The lower electrode is grounded, and base material and short fibers are placed on it; high-voltage direct current is applied to the upper electrode plate, and a strong electric field is formed between the two electrodes. Taking imitation suede products as an example, the working process is: connect the negative electrode of the 35-60 kV high-voltage power supply to the metal mesh frame equipped with fluff, and place the base material coated with adhesive on the metal bracket. And connect it to the positive pole of the power supply to form an electrostatic field between the metal mesh frame and the metal bracket. After the shaped fluff passes through the metal mesh, it enters the electric field and is polarized, causing it to rotate parallel to the direction of the electric field, sink to the base and be adhered, forming a flocked article. At present, the main product types include: fiber products such as carpets, cushions, artificial fur and printed velvet; plastic products such as decorative fabrics, protective sound-absorbing fabrics and products with surface elasticity; metal products including decorative materials, protective materials and heat insulation Materials, etc.; others include wooden shells and paper shells used for decoration.
Xerographic copying uses photoconductive sensitive materials to transfer charges according to the image during exposure to retain electrostatic latent images. After certain dry development, image transfer and fixation, a copy is obtained. The materials used are non-silver photosensitive materials. There are two types of electrostatic printing: direct method and indirect method. The former directly copies the image of the original onto photosensitive paper coated with zinc oxide, also known as a coated paper copier; the latter changes the original image into an electrostatic latent image on the photoreceptor and then transfers it to ordinary paper, so Also known as a plain paper copier. According to whether the developer is dry powder or liquid, it can be divided into two categories: dry type and wet type. At present, dry indirect electrostatic copiers are mainly produced in various countries around the world. Commonly used copying materials include inorganic photoconductive materials such as zinc oxide, selenium, and cadmium sulfide, as well as organic photoconductive materials such as polyvinylcarbazole (PVK) and trinitrofluorenone (TNF).
The process of electrostatic copying is as follows: first, the sensitive layer is evenly charged; then the original is used for reflection exposure; an electrostatic latent image is formed due to the difference in charge density of the photoconductive layer in the illuminated part, and is covered with a thermoplastic toner for dry development (development) ; Cover the white paper on the sensitive layer and charge it again to transfer the image to the paper (transfer); instantaneously heat the toner to fix it on the paper (fixing) to obtain a copy. Compared with the past wet development copying technology, the electrostatic copying system has significant advantages: simple, fast, clear, and no pollution to the operator. Xerographic copying technology has developed greatly in recent years. Modern electrostatic copying machines have high copying speeds, can expand and reduce printing, and can also copy color originals. It meets the needs of modern society for information recording and information display. In the 1970s, the copier controlled by a microprocessor came out, allowing the copier to perform complex programs and have multiple functions. For example, the self-diagnostic display system allows users or maintenance personnel to quickly troubleshoot, improving work quality and efficiency. Electrostatic copying, combined with modern communication technology, electronic computer technology and laser technology, has become an important part of the information network. As a terminal for reading and recording information during short or long distance transmission, it is a part of office automation.
Electrostatic plate making uses the principle of electrostatic copying to turn a paper plate with photoconductive properties into an electrostatic photographic plate. Compared with traditional photographic plate making, electrostatic plate making has fast speed, fewer processes, low cost, easy operation, and saves silver. Among them, the photoconductive paper plate is the key. Zinc oxide paper plate is generally used with low cost, easy production and low toxicity. It is made of zinc oxide powder dispersed in insulating resin and coated on the paper base with some other substances.
Applications in high-tech fields Static electricity has also been used in some high-tech fields, mainly including: ①Electrostatic rocket engines. It is a type of electric rocket engine. Unlike chemical rocket engines, the energy used is separated from the working medium. The characteristics of electrostatic rocket engines are high specific impulse and long life (it can be started tens of thousands of times and has a cumulative working time of tens of thousands of hours), but its thrust is very small. It is suitable for attitude control, position maintenance and interstellar navigation of spacecraft. The working fluid of the electrostatic rocket engine (such as mercury, cesium, hydrogen, etc.) passes from the storage tank through the ionization chamber and is ionized into ions, which are accelerated to form a beam under the action of the electrostatic field force of the extraction electrode. The ion beam couples with the electrons emitted by the neutralizer to form a neutral high-speed beam, which is ejected to generate thrust. The thrust is usually between (0.5~25)×10-5N, and the specific impulse is 8500~20000 seconds. ②Electrostatic bearings. A sliding bearing that uses electric field force to levitate the shaft. The combination of electric field force and magnetic field force is the combined bearing. Because electrostatic bearings require high electric field strength, their applications are limited and are only used in a few special instruments. ③Electrostatic gyroscope. Also known as electric floating gyroscope. It is a type of gyro sensor. Evenly distributed high-voltage electrodes are installed around the metal spherical hollow rotor to form an electrostatic field on the rotor, and the electrostatic force is used to support the high-speed rotating rotor. This method is a spherical support. The rotor can not only rotate around the axis of rotation, but also rotate in any direction perpendicular to the axis of rotation, so it is a free rotor gyroscope type. The electrostatic field only has suction force. The closer the rotor is to the electrode, the greater the suction force is, which makes the rotor in an unstable state. A set of support circuits is used to change the force on the rotor to keep the rotor in the center position. The electrostatic gyroscope adopts non-contact support and has no friction, so it has high accuracy. Its drift rate is as low as 10-3 to 10-5 degrees/hour. It is an important component of the high-precision inertial navigation system. But it cannot withstand larger shocks and vibrations. Another disadvantage is that the structure and manufacturing process are complex and the cost is high. ④Electrostatic lens is a type of electronic lens. A rotationally symmetric electrostatic field is formed by applying a certain DC voltage to several rotationally symmetric conductor electrodes. For example, an immersion lens composed of double cylindrical electrodes with equal or unequal radii; a single-potential lens composed of 3 cylinders or 3 apertures with equal or unequal radii; and a cathode, modulation electrode and anode. constitute a cathode lens.
Static electricity can also be used in medical treatment.
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