What issues should be considered when using AC and DC ionization devices?
Ionizing fans and other ionization devices can be divided into two main categories based on the high voltage used in their discharge electrodes (discharge needles): AC and DC. AC ionization devices are further divided into high-frequency and ordinary AC (commercial frequency) types, while DC ionization devices are divided into continuous DC and DC pulse types.
The difference between AC and DC ionization devices lies in the fact that AC ionizers can alternately generate positive and negative air ions on a single discharge needle, and the discharge electrode consists of both the discharge needle and a grounding electrode. DC ionizers, on the other hand, do not require a grounding electrode, and their discharge electrodes consist of independent positive and negative discharge needles. In situations without external airflow (such as fans or compressed gas), DC ionizers have a longer ionization distance than AC ionizers. In situations with external airflow, the ionization distance mainly depends on the structure of the ionizer, the airflow rate, and the strength of the high-voltage power supply. The key difference between AC and DC ion removal devices lies in their ion balance. AC ion removers generate both positive and negative ions on the same discharge needle, so even with wear and tear over time, the ion balance remains relatively stable, resulting in better performance. DC ion removers, however, have separate positive and negative electrodes. This leads to poorer ion balance when used in close proximity. Furthermore, environmental factors and varying degrees of contamination on the needles can affect ion balance, especially over time when the positive and negative electrodes wear at different rates, which cannot be corrected even after cleaning.
Because the discharge needles become contaminated over time, directly impacting the ion removal performance and ion balance of the ion fan, ion gun, and ion bar, regular cleaning of the electrode surfaces is essential. This is particularly important for DC ion removers, which are more susceptible to contamination and require more frequent cleaning than AC ion removers. The different wear rates of the positive and negative electrodes necessitate periodic ion balance checks, and the discharge needles should be replaced when severely worn.