JPS5925613B2 - electret filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electret filter used for removing particulates mixed in gas or liquid for purposes such as air purification, dust collection, and dust removal.

Electric dust eliminators and electrostatic filters are already in use as devices to purify the air by removing cigarette smoke and dust from the air, but these devices not only have high equipment costs but also lack effective performance. The disadvantage is that it has a short lifespan.

In order to overcome the drawbacks of the conventional devices, the present invention utilizes an electret polymer film as a filter to provide an electret filter that has excellent dust collection performance and a long service life.

That is, the present invention uses an electret synthetic resin film as a nonwoven fabric made of fine metal fibers, paper, synthetic resin,
The present invention relates to an electret filter that is arranged uniformly in the thickness direction via a spacer such as aluminum foil.

The material of the film used in the present invention may be any resin that can be formed into a film by melt molding, casting, cutting, etc., such as polyolefin resin,
Thermoplastic resins such as polyester resins and polyamide resins,
Thermosetting resins such as phenol resin, formaldehyde resin, urea/formaldehyde resin, and melamine/formaldehyde resin are used.

Among these, ethylene, which has excellent electret performance,
Polymers mainly composed of α-olefins such as propylene,
For example, in addition to polyethylene, polypropylene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polystyrene, polyester resins such as polyethylene terephthalate, and polycarbonate resins are suitable. includes blended or graft copolymerized derivatives of unsaturated carboxylic acids and their anhydrides.

These resins may also contain conventionally known stabilizers, such as antioxidants 1. A heat stabilizer is added as necessary.

The synthetic resin film is usually used in a thickness of approximately 3 μm to 3 mm, and may be stretched in one or two directions as necessary.

Further, examples of the film include those subjected to foaming treatment, crosslinking treatment, etc., and non-woven films, and two or more sheets or two or more types of films may be laminated.

The synthetic resin film is made into an electret by various conventionally known methods such as a thermal electret method, an electroelectret method, a radioelectret method, a mechanoelectret method, a magnet electret method, a photoelectret method, and the like.

This electret processing is performed at the same time as the film forming, or before or after the film forming, depending on the purpose.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the structure of the filter, in which a large number of electret films 1 are arranged in the thickness direction.

The medium to be dedusted flows parallel to the plane of the film.

In terms of dust collection efficiency, it is particularly preferable that the distance between the films 1 (indicated by arrows F) be about 50 μm to 51 nrIL.

In order to arrange the films at such a distance, it is preferable to use a nonwoven fabric made of fine metal fibers as a spacer between the films.

As a result, among the dust in the passing medium, coarse dust is collected by the nonwoven fabric of the spacer, and fine dust is attracted to the film 1 and collected.

In addition, as an example of the arrangement of the film 1, other preferable embodiments include:
The sectional view of FIG. 2 is an enlarged view of the portion A in FIG. 1.

In FIG. 2, a spacer 3 having a convex portion is provided between the films 10.

As shown in FIG. 3, the spacer 3 has convex portions integrally provided on both sides.

Paper, synthetic resin, aluminum foil, etc. are used as the material for the spacer.

In the present invention, a particularly suitable spacer is one in which the convex portion has a meandering shape, as shown in the partial perspective view of Fig. 4, and the area in which the passing medium contacts the film is expanded, further improving the dust collection efficiency. do.

Further, the voids formed by these spacers 3 may be further filled with an air-permeable material such as fibers, if necessary.

In the present invention, it is preferable to have a structure in which a large number of electret films are arranged in the thickness direction, and even if the charge signs of each film are different as shown in FIG. Even the sign shows its excellent dust collection efficiency.

In particular, when the same reference numerals are placed opposite each other as shown in FIG. 5a, this structure can be obtained by sequentially folding a long film, making it easy to manufacture the filter.

For example, there is a method of stacking a long film and a spacer and folding them one after another.

FIG. 6 is a partial sectional view showing another embodiment of the present invention,
It has a structure in which the film 1 and the spacer 3 are wound into a roll.

Furthermore, the shape of the spacer is not limited to these examples; for example, there are chevron-shaped cross sections as shown in the partial cross-sectional view of FIG. 7 and the partial perspective view of FIG. By meandering as shown in FIG. 9, the contact area of the medium is expanded and the dust collection efficiency is further improved.

The filter of the present invention has extremely low pressure loss and is energy saving, and has excellent yield performance in both seasonal efficiency and aging efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the filter. FIGS. 2 and 7 are partially enlarged cross-sectional views of the portion A in FIG. 1. 3, 4, 8, and 9 are partial perspective views of the spacer. FIG. 5 is a sectional view illustrating the arrangement of films. FIG. 6 is a partial sectional view showing another embodiment of the filter. 1...Electret film, 2...
...Breathable material, 3,4...Spacer.

Claims (1)

[Claims] 1. An electret filter characterized in that an electret synthetic resin film is arranged in the thickness direction through a spacer such as a nonwoven fabric made of fine metal fibers, paper, synthetic resin, or aluminum foil.