A device is provided for collecting particles from a gas for subsequent analysis with a particle analyzer. The device includes an ionizer with at least one ion-emitting unit which emits ions and a collector for collecting particles charged by the ions. An electrically conductive capturing or collecting device is electrically connected to the collector of the ionizer.

A dust is electrostatically charged using an ion-releasing device adapted to release only ionized air with occurrence of a corona discharge, thereby reducing the amount of power consumed and the amount of ozone generated to the utmost. An electric dust collector includes a charging section having a discharging electrode and an earthed electrode, a dust-collecting section having a voltage-applied electrode and an earthed electrode and an air feed fan. Dust introduced into the dust collector is electrostatically charged by breaking the air insulation by a corona discharge occurring in the charging section to produce ionized air and then removed in the dust-collecting section where an electric field is formed. However, because the corona discharge is generated, there is a problem that the discharged current is large, and the amount of power consumed and the amount of ozone generated are large.

An electrostatic precipitator type filter is combined with replaceable, polarizable trapping media. In one aspect of the invention, the media is fitted between polarizing plates. In another aspect, the media is coated in sections to form a conductive surface which serve as the equivalent to the charged plates of the precipitator. These electrodes may be alternately displaced to provide a ready means to effect electrical connections.

An electronic air filter assembly includes filter media disposed on opposite sides of an electrified charging screen. The filter media and charging screen are held between outer screens. The outer screens are held together in an assembled condition by pressure-sensitive securements and can be pulled apart to disassemble the filter assembly by applying an outer screen-separating force sufficient to overcome the holding force of the securements.

Structures for V-bank electrostatic air filters are described. The V-bank air filters are assembled from two side panels, perforated top and bottom plates, a narrow end wall and an open wide end for the intake of air to be filtered. A pair of enclosure plates are pivotally mounted to the side panels in a parallel relationship to the respective top and bottom plates to form a pair of rectangular enclosures for respectively supporting electrostatic filter pads. The enclosure plates pivot open for removal and replacement of the filter pads. The side panels, top and bottom plates and rear wall are made from sheet metal blanks using cutting, bending and stamping processes. The enclosure plates are made from sheet metal blanks or welded wire structures. The advantage is that the structures are manufactured using simple automated processes and are quickly assembled without sub-assembly, thus time and labour are saved and costs are reduced.