Design Selection of Ionization Static Electricity Eliminators
In the electronic industry, static electricity is constantly generated and accumulated during production processes. Even if the design of other chapters in this specification is well done, static potentials exceeding the specified limits will still form in certain parts of the anti-static work area. Therefore, using ionization static electricity eliminators to neutralize static charges on local surfaces and in the air is an effective means.
Ionization static electricity eliminators come in many types, with varying operating principles, product forms, elimination efficiency, environmental requirements, and prices.
Ionization static electricity eliminators can be classified into several types according to the air ionization principle, including self-induction type, high-voltage type, isotope type, and photoelectronic type.
1. Self-induction type static electricity eliminators do not require an external power supply, have a simple structure, are easy to install, and are suitable for use in confined spaces, but have a weak elimination effect.
2. High-voltage ionization static electricity eliminators come in various forms, including power frequency high voltage, high frequency high voltage, pulse high voltage, and DC voltage.
(1) Power frequency high voltage type has high emission density and uniformity, but has a good elimination effect. (2) High-frequency high-voltage type achieves simple coupling corona discharge through capacitors, resulting in low short-circuit current at the needle electrode and good explosion-proof performance.
(3) Pulse high-voltage type has low requirements for airflow coordination, good consistency, and is suitable for full ion protection in indoor environments. It can also be used in conjunction with ion spray guns, ion air showers, and ion purification workbenches.
(4) DC high-voltage type is suitable for applications requiring a greater static elimination distance, but should be equipped with a controllable device for power output voltage rise/fall and polarity changes.
3. Isotope ionization static eliminator does not require an external power supply, has a simple structure, and is easy to maintain. The design should be based on the radioactive intensity and half-life of the isotope, as well as the ionization and penetrating power of the radiation.
4. Photoelectron ionization static eliminator has good static elimination effect and is suitable for certain high-requirement environments.
Ionization static eliminator consists of three parts: a high-voltage power supply, a corona discharger, and a ventilation system. The design should consider the reasonable configuration of the power supply, air source, and corona discharger. Ionization static eliminators can also be classified by form, including: pedestal-type ion fans, tubular ion nozzles, cabinet-type ion fans, ion guns, and electrostatic ion bars.
By application location, they include: in-unit laminar flow hood type, cleanroom type, air-conditioned room type, workbench type, and compressed gas type.
By arrangement, they include: needles, fine rods, grids, emitters, and ion air.
Therefore, the design should comprehensively utilize different types of ionization elimination methods according to different locations and process requirements. It should also consider the corona discharge, discharge corrosion, and electrostatic shielding issues generated by the ionization static eliminator itself, as well as the resulting environmental problems such as dust, ozone, radioactivity, and noise, to minimize the negative impacts of the ionization static eliminator and achieve better static elimination performance and overall performance.