JPS60238169A - Air filter - Google Patents

Abstract

PURPOSE:To attain to prolong the life of an air filter by preventing the lowering in collection efficiency, by alternately changing over the voltage apply direction of the DC high voltage power source in the charging part in the upstream side to perform + discharge and - discharge while availably utilizing both of the dipole and the polarizer of an electret filter material. CONSTITUTION:A charging part 20 for charging dust particles in gas such as air is provided and a collection part 21 for collecting charged dust particles is provided in the downstream side of said charging part 20 while a change-over apparatus 24 for changing over a discharge direction is arranged in the charging part 20 and an electret filter material 26 is used in the collection part 21. That is, by changing over the apply direction of a DC high voltage power source with respect to a discharge wire in the charging part by a change over switch 24, both polarized plus and minus sides of the electret filter material in the collection part can be availably utilized and, therefore, highly efficient collection effect is obtained and high collection efficiency can be held for a long time as compared with a conventional filter and long life is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an air filter for collecting dust particles in the air. In particular, an electret filter Pa is used in the collection part, and a dust filter is installed on the upstream side of the air filter. This invention relates to an air filter equipped with a charging section that charges particles.

Conventional configurations and problems There have been many types of dust collectors in the past for removing dust particles from gases such as air. The device used is already known, and its configuration is shown in FIG. Reference numeral 1 denotes a charging section, which has a discharge wire 2 and a ground parallel plate electrode 3, and a DC high voltage power source 4 between the discharge wire 2 and the ground parallel plate electrode 3.
is connected. A collection section 6 is provided on the downstream side of the air flow of the charging section 1. The collection section 6 is composed of an electret filter P-shaped 6. As shown in FIGS. 2 and 3, the electret filter Fa6 is fibrous and has a dipole polarizer structure.

In the above configuration, when the air flow 10 containing dust particles flows in due to the action of a blower or the like, the dust particles become fully charged due to the corona discharge occurring between the discharge wire 2 and the ground parallel plate electrode 3 in the charging section 1. be done. Next, in the collection section 5, the dust particles are attracted to one side of the dipole polarizer of the electret filter Pa6 by electrostatic force and are collected.

As is clear from the above description, the adhesion of dust particles is concentrated only on one side of the electret filter Pa6. That is, if the corona discharge of the charging section 1 is ten discharges,
If the electret filter is collected only on one side of the P pillow, and if the corona discharge is one discharge, it will be collected only on the + side of the electret filter, and therefore only one of the dipole polarizers of the P cane will be used. The disadvantages are that the efficiency decreases quickly, the amount of dust collected is small, and the lifespan is short.

OBJECT OF THE INVENTION Therefore, an object of the present invention is to eliminate the drawbacks of the conventional examples, maintain dust collection efficiency for a long period of time, and extend the life.

Structure of the Invention In order to achieve this object, the present invention has a charging section on the upstream side and a collection section using an electric left filter F shape on the downstream side. By alternating the direction of the applied voltage, ten discharges or one discharge is performed, and by effectively utilizing both dipole polarizers of the electret filter Pa, the collection efficiency is prevented from decreasing and the service life is extended. It is something.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. Fourth
In the figures to FIG. 6, 20 is a charging section and 21 is a collection section. The charging section 2o includes a discharge wire 22 and a parallel plate electrode 2.
3, and a DC high voltage power source 26 is connected between the discharge wire 22 and the parallel plate electrode 23 via a changeover switch 24. A collection section 21 is disposed downstream of the charging section 20, and the collection section 21 is constituted by an electret F crosspiece 26. The electret Pa26, as shown in Figures 2 and 3, is made of fibers that have been treated with high voltage in advance so that the inside is always polarized, and then turned into a mat shape and then folded and molded. This is what I did.

In the above configuration, when the gas flow 30 such as air containing dust particles first flows into the charging section 20 due to the action of a blower or the like, if the changeover switch 24 is set in the direction a, the discharge wire 22 and A DC high-voltage power supply 26 is connected between the parallel plate electrode 23 and a DC + voltage is applied to the discharge wire 22, so that a positive corona discharge is performed and the dust particles are positively charged. The charged dust particles are collected in the collection section 2
1 and is attracted to the polarized negative side of the electret F crosspiece 26 as shown in FIG. 5 and collected. In this state, only the negative side of the electret Pa26 contributes to collection.

Next, when the changeover switch 24 is set in the direction b, the discharge wire 22 performs negative corona discharge in the charging section 2o, and the dust particles are negatively charged. As shown in the figure, the electret is attracted to the positive side of the electret P crosspiece 26 and collected.

Naturally, the collection of dust particles passing through the electret Pa involves normal mechanical collection effects such as collision and blocking.
In addition to obtaining even higher collection efficiency through the collection action of the electrostatic force mentioned above, by appropriately switching the direction of application of the DC high voltage power supply 26 using the changeover switch 24, high collection efficiency can be maintained for a longer period of time than before. can be maintained and have a long lifespan.

Note that although the charging section 20 has been shown as an example using the discharge wire 22 and the parallel plate electrode 23, a combination of a needle-like electrode and a cylindrical electrode or a rectangular electrode, or a combination of a discharge wire and a rope-like electrode may be used.

The P-shaped electret of the collecting section can be folded to obtain higher efficiency, but it may also be in the form of a flat plate.

Effects of the Invention As is clear from the above explanation, the present invention has a charging section and a collection section, and the charging section can collect the discharge wire by switching the direction of application of high voltage DC power to the discharge wire using a switch. Since the polarized positive and negative sides of the electret P crosspiece can be effectively used, a highly efficient collection effect can be obtained, and the high collection efficiency can be maintained for a longer time than before.
This has the effect of providing a long life.

[Brief Description of the Drawings] Figure 1 is a schematic diagram showing the configuration of a conventional air filter, and Figures 2 and 3 illustrate the structure of the conventional example and the structure of the electret P crosspiece used in the present invention. FIG. 4 is a schematic diagram showing the configuration of an air filter in an embodiment of the present invention, and FIGS. 5 and 6 are perspective views of the reservoir for explaining the present invention in detail. 2o... Charge part, 21... Collection part, 22...
...Discharge wire, 23...Parallel plate electrode, 24.
......Selector switch, 26...DC high voltage power supply, 26...Electret P crosspiece. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (1)

[Claims] A charging unit that charges dust particles in a gas such as air, and a collection unit downstream of the charging unit that collects the charged dust particles, and the charging unit includes a switching device that switches the discharge direction. , the collection section is an air filter using electret Pa.