The charging effect of contact charging method is very good, but in the working process, due to the direct contact between the nozzle and the discharge electrode, it is easy to cause leakage, endanger the operator or other electronic equipment, and have very high requirements for insulation. Figure 1 frontiersin Figure 1. Contact charge schematic diagram. 2.1.2. Corona type At present, corona charging is one of the most widely used methods in electret charging. It is composed of a needle-shaped electric level, a flat electric level and a metal grid. The corona charging method is to install the discharge electrode near the nozzle.
A released, the tip discharge phenomenon will be generated, so as to ionize the air near the nozzle (as shown in Figure 2) and generate charged particles. When the ejected droplets pass through the ionized area, they will collide with the charged particles and take charge. The voltage of corona charging mode is Spain phone number list usually above 20 kV to achieve better charging effect, and has high requirements for voltage. Figure 2 frontiersin Figure 2. Corona charging schematic diagram. 2.1.3. Inductive Inductive charging is to connect the electrostatic power supply with the inductive electrode to form an inductive electric field, as shown in Figure.
Under the action of the induced electric field, the charge distribution of the ejected droplet will change, and the charge with the same polarity as the induced electrode will be introduced into the earth, so the droplet will carry the charge with the opposite polarity to the induced electrode. Inductive charging has low voltage requirements and is widely used. Figure 3 frontiersin Figure 3. Inductive charging schematic diagram. 2.2. Charging mode selection The principles of the above three charging modes are quite different, so the most suitable charging mode should be found out in the design.