JPS61138550A - Air filter - Google Patents

Abstract

PURPOSE:To prolong a collection life of an air filter by providing both an electrical charge part on the windward side and a collection part on the leeward side and impressing an electric field to a filter medium of the windward side between the electret filter medium of two layers by means of an electrical discharge wire and a lattice-shaped electrode. CONSTITUTION:When a dust-laden gas stream 28 is flowed into an electrical charge part 20, DC voltage is impressed between the electrical discharge wires 21 and the parallel plane electrodes 22 by a DC high voltage power source 23 and the dust is charged and thereafter entered into a collection part 24. In an electret filter medium 25 of the windward side, the polarization is strengthened by the electric field between the electrical discharge wires and a lattice-shaped electrode 27 and the charged particles are collected. Furthermore the dust particles are collected by an electret filter medium 26 of the leeward side and the purified air is discharged. Even when the collection of dust particles is advanced, the deterioration of the collection efficiency is made less because the static electric force of the filter medium 26 is subjected to the backup by the electric field.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air filter for collecting dust particles in the air.

BACKGROUND OF THE INVENTION There are many types of air filters used to remove dust particles from gases such as air. 1 of them
An air filter in which a charging portion is provided on the windward side and an electret filter medium is used on the leeward side will be described based on FIG. 3.

In the figure, discharge wires 2 and parallel plate electrodes 3 are arranged alternately and in a row on the windward side of the charging section 1t, and a DC high voltage power source 4 is connected between the discharge wires 2 and the parallel plate electrodes 30. A collection section 5 made of an electret filter material is provided on the downstream side of the airflow of the charging section 1.

In the above configuration, the air flow 6 containing dust particles flows into the charging section 1 by the action of a blower or the like. In the charging section 1, since a DC high voltage (■) is applied to the discharge wire 2 and a DC high voltage (○) is applied to the parallel plate electrode 3, a corona discharge (■) is generated between the discharge wire 2 and the parallel plate electrode 3. The dust particles that have flowed into the charging section 1 are charged to ■ by corona discharge. These charged dust particles then flow into the collection section 5,
Dust particles are attracted to the θ side of the dipole polarizer of the electret filter medium by electrostatic force, and are efficiently collected.

Problems to be Solved by the Invention As shown in FIG.
When the charged particles layer, the electric charge on the filter medium and the electric charge on the dust particles appear to be cancelled, and the electrostatic force on the electret filter medium 7 weakens. This caused a decrease in collection efficiency. That is, although high dust collection efficiency can be obtained initially, the collection efficiency gradually decreases and the collection life is short.

The present invention was made in view of the conventional problems, and an object of the present invention is to provide an air filter that can suppress the decrease in dust collection efficiency and extend the dust collection life.

Means for Solving the Problems In order to achieve this object, the present invention has a charging section consisting of a discharge wire, a parallel plate electrode, and a DC high voltage power supply on the windward side, and a two-layer electret filter filter medium and its electret on the leeward side. It consists of a collection part in which a grid-like electric @A is provided in the middle of the filter medium, and the discharge wire is attached to the windward side of the electret filter medium of the two layers of electreno 14' material,
With the above-described structure, the electret filter media on the windward side applies an electric field using discharge wires and grid electrodes, which prevents a decrease in electrostatic force and allows long-term use. Highly efficient dust collection can be carried out & Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In Figure @1, the charging section 20 consists of a discharge wire 21, a parallel plate electrode 22, and a DC high voltage power source 23 connected between the eccentric wire 21 and the parallel plate electrode 22.0 The collecting section 24 consists of an electret f provided between the filter medium 25.26 and this electret filter medium 25.26
An electret filter medium 25 consisting of hexagonal electrodes 27 and full on llL is provided between the charging section 21 and the grid electrode 27 connected to the DC high voltage power source 23. Electret filter media 2 on the leeward side
6 is provided on the leeward side of the grid electrode 27.

In the above configuration, a gas flow 28 such as tr air containing dust particles
However, due to the action of the feeder etc., the load WL section 20 is first
When flowing into the discharge wire 21, a DC high voltage power supply 23 is connected between the discharge wire 21 and the parallel plate electrode 22, and the eccentric wire 21 has a
Since a DC voltage is applied, a positive corona discharge occurs throughout the process, and the dust particles are positively charged. The charged dust particles then reach the collection section 21 . In the collecting section 21, first, the electret filter medium 25 provided between the discharge wire 21 and the grid electrode 27 is further polarized by the electric field between the eccentric wire 21 and the grid electrode 27, and becomes charged. This will collect the dust particles. The air light that has passed through the electret filter medium 25 and has been purified is further filtered by the electret filter medium 26 on the leeward side.
As the dust particles are collected, the air becomes clean and flows out in the direction of the arrow 29. This collection is mainly performed by the filter medium 25, and even if the collection of dust particles progresses, the discharge wire 21 and the lattice-shaped Since the electrostatic force of the electret filter medium 26 is backed up by the electric field of the electrode 270, the drop in collection efficiency is reduced. Furthermore, the electret filter medium 26 on the leeward side can prevent a decrease in collection efficiency.

In Figure 2, a represents the air filter in this embodiment;
b is the air filter of the conventional example shown in FIG. 3, and C is the electret filter 2 on the lower side of the air filter of this embodiment.
There is no 6.

As is clear from the figure, the air filter of this embodiment can maintain high dust particle collection efficiency for a long time compared to conventional air filters.

In addition to the effects of the invention, as is clear from the description of the embodiments, the present invention provides the entire electret filter medium on the windward side, and the electret filter medium is provided between the eccentric wire and the grid electrode.

By installing two layers of electret filter media on the leeward side, it is highly efficient at collecting dust particles than before, and can completely prevent any decrease in collection efficiency, making it a longer-lasting air filter. be.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the one-row air filter of the present invention, Figure 2 is a graph for comparing the change in fruit thinning efficiency of the present invention with the conventional example, and Figure 3 is a diagram of the conventional air filter. Diagram,
FIG. 4 is a structural diagram of the same electret p material. 2o...Charging part, 21...Discharging wire, 2
2...Parallel plates are poles, 23...DC high pressure retrograde source, 24...Collection section, 25.26...
・Electret filter media, 27... Lattice electric wire, etc. Name of agent: Patent attorney Satoshi Nakao, male, and 1 other person 11 cigarettes - Fuku,!

Claims (1)

[Scope of Claims] A charging section consisting of a discharge wire that applies high DC voltage on the windward side and parallel plate electrodes, two layers of electret filter media on the leeward side, and a grid-like electrode provided between the electret filter media. an air filter comprising: a collecting section; the air filter is configured to apply an electric field to the windward side of the two layers of electret filter media by the discharge wire and the grid electrode; (2) The air filter according to claim 1, wherein the grid electrode is a breathable conductive electrode.