Outline and research trend of electrostatic precipitator and particulate removal technology for household air purifier

Abstract

The technology of removal of fine particles suspended in the air, is central to the functions of dust collection, deodorization, and sanitization expected from household air purifiers used to improve air quality in living spaces. The filtering mechanism, which is a filter-type technology that is the majority of devices on the market, operates by the action of inertia, interception, diffusion, gravity, and electrostatic forces. Mechanical collection such as inertia is advantageous for large particle size, and electrostatic collection is advantageous for small particle size. In a household air purifier, an electret filter in which fibers are charged in advance is used to collect fine particles while reducing pressure loss. However, the charge of the fibers disappears when the combustion-generating particles are collected. In order to maintain this, improvement is being attempted by means of the fiber surface modification and recharging by friction. On the other hand, there is an electrostatic precipitating technology that maintains electrostatic force by supplying power. When the indoor air is circulated for cleaning, the processing air volume has a large effect on the performance, and therefore, an electrostatic precipitator having a low airflow resistance is advantageous in this respect. Electrostatic precipitator has power consumption by discharge and ozone generation, which are not aspects of filters. To improve this, charging by induction charging or gradient force, high-density pulse ion charging by insulation breakdown of coated ground electrodes, etc. has been studied. This paper gives an overview of the technology for removing particulates, and then describes an overview of the electrostatic precipitator technology and the research trends.