JPS61268315A - Filter material - Google Patents

Abstract

PURPOSE:To extend the life of a filter material and to enhance filtering capac ity, by forming at least the three-stage change in density to the surface direction of a filter material and stepwise advancing clogging by the collection of dust. CONSTITUTION:By stepwise forming unevenness to the surface of a base mate rial 1 corresponding to the thickness of the base material 1, a low density part having relatively large voids 2a, a medium density part having medium size voids 2b and a high density part having small voids 2c are formed. By this method, the collection of dust is stepwise advanced and the flow speed ratio of the uneven part is adequately changed to enhance filtering capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a filter material, and particularly to a filter material suitable for oil filters, air filters, etc. of internal combustion engines.

[Technical background of the invention]

The requirements for a filtration material used in automobile oil filters and air filters are to have filtration performance that effectively removes dust and other particulates present in the fluid to be filtered, and to maintain good filtration over a long period of time. It is especially important to continue to maintain performance.

From this point of view, various filtration media have been proposed in the past, but conventional filtration media are not always fully satisfactory in terms of simultaneously improving filtration performance and reducing lifespan. It's not something I can do.

For example, filter media in which a density gradient is created in the thickness direction of the filter paper by combining filter papers with different #AN density and thinness have been known (for example, Japanese Patent Publication No. 54-40778).
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These density gradient type filter media are formed so that they change from coarse to dense in the direction from the upstream side to the downstream side of the flow of the fluid to be filtered, so large particles are captured in the low density layer and the density increases. Although fine particles are captured in the layer, a good sieve fraction is excellent in that it is effective and can improve the life to some extent, but it has the following drawbacks.

(b) In the conventional compact gradient type filtration method, the flow velocity when passing through the filter material is high, and dust adhesion (trapping) due to mere contact is difficult to occur, and the dust is firmly captured so that it penetrates into the deep layer. (So-called deep filtration), there is a problem that the filter medium is easily clogged and the pressure loss increases considerably.

(b) In conventional filter media, the porosity of the surface of the filter media on the upstream side of the fluid to be filtered is large, so dust is easily incorporated into the surface layer of the filter media, resulting in the formation of a dust cake layer on the surface layer of the filter media. The drawback is that it is difficult. Therefore, it is not possible to expect a filtration function (that is, a primal filter function) by the cake layer, and there are major limitations in the 1L that aims to extend the life.

[Summary of the invention]

The present invention is an IC made in view of the above-mentioned points,
Our aim is to provide filter media that is superior in both filtration performance and long life.

In order to achieve the above object, the filter medium of the present invention is characterized in that it has a density gradient in the surface direction of the filter medium, and the density gradient is formed by at least three stages of density change.

[Embodiments of the invention]

EMBODIMENT OF THE INVENTION Hereinafter, the filter material of this invention will be explained in detail based on the Example shown in an accompanying drawing.

As shown in the cross-sectional conceptual diagram of FIG. 1, the filter material of the present invention is
The base material 1 has a density gradient in its surface direction, for example, a low-density portion having relatively large pores 2a, a medium-density portion having medium-sized pores 2b, and a high-density portion having smaller pores 2C. are formed in stages. It is important to provide three or more stages of such density changes.

In addition, the density change in this case may be in a manner in which it changes continuously from high density → medium density → low density, or it may be in a manner in which the density configuration of three or more stages changes intermittently or randomly. good.

As described above, since the filter medium of the present invention has at least three stages of density change in the 100 directions of the filter medium,
The clogging of the filter medium due to the capture of Gess 1 to 1 can be progressed in stages. For example, if the density changes in three stages, clogging due to dust trapping progresses first in the high density part, then moves to the medium density part, and then to the low density part. Therefore, compared to the case where the density in the plane direction is constant, the effect of the preferential sieving is exerted by the difference in the density in the plane direction, and the increase in pressure loss due to clogging can be made gradual and gradual. This makes it possible to achieve even longer life. Furthermore, since the removal of fine particles is carried out in the high-density part, and the removal of Okawa particles is more likely to be carried out in the layer of the low-density part, by appropriately selecting the distribution of density change, the density range, and its area ratio. , it is possible to achieve not only a longer life but also an improvement in filtration performance.

FIG. 2 shows an example in which a stepwise change in density is created by forming irregularities on the surface of the filter material. That is, by forming unevenness in stages = 4 - on the surface of the base material 1, a low density part having relatively large pores 2a and a medium density part 2b are formed according to the thickness of the base material.
A medium-density portion having pores 2C and a high-density portion having small pores 2C are formed. Therefore, the configuration as shown in FIG. 2 is advantageous in that a difference in density can be created at the same time by providing unevenness using means such as a roller in the manufacturing process of the filter medium.

Further, by providing a number of concave and convex portions on the surface of the filter material, the flow resistance changes between the four portions and the convex portions, which has the effect of allowing dust to be captured in stages. Furthermore, it is advantageous to improve filtration performance by appropriately changing the flow velocity ratio of the uneven portions. In general, large particles gather in low-density areas, and small particles tend to be trapped in high-density areas, so creating a structure like the one shown in Figure 2 maintains the level of the dust cake layer at a constant level, thereby preventing irregularities. This is advantageous in maintaining a constant flow rate ratio and improving filtration performance.

FIG. 3 shows another embodiment of the present invention, in which a three-stage density change is achieved by forming irregularities on both the front and back surfaces of the base material 1.

Moreover, the density change in the above-mentioned plane direction may be provided so that a lattice pattern is formed when viewed from the surface of the filter medium. For example, as shown in the conceptual diagram of FIG. 4, density changes can be formed in a checkered pattern by intersecting high-density areas (solid line areas) and low-density areas (broken line areas).

The filter material shown in FIG. 5 is an embodiment in which a raised layer constituted by raised fluff 3 is formed on the surface of the filter material on the upstream side of the flow of the fluid to be filtered (in the direction of the arrow in the figure). In this way, by forming a raised layer on the surface of the base material so as to face the flow of the fluid, dust in the fluid is easily captured on the raised layer like a rime and a dust cake layer is formed. By utilizing the filtration effect of this Goo 4 layer, the filtration performance can be further improved.

As constituent materials of the filter medium, natural fibers, synthetic fibers, and mixtures thereof, which are conventionally used as raw materials for filter paper, are used, and additives such as binders and colorants can also be used as necessary.

In addition, as a method for raising the surface of the filter material, for example, by supplying a papermaking raw material slurry flow to one side of the papermaking net and simultaneously sucking it from the other side of the papermaking net, the longitudinal direction of the fibers is directed against the papermaking surface. A raised layer can be effectively formed by vertically oriented.

When using the filter material of the present invention for an air filter or oil filter of an internal combustion engine, in order to expand the filtration area,
It is preferable to form the filter into a cylindrical shape with a chrysanthemum-like cross section, and the filter structure is formed by joining a disc-shaped metal plate to the rough edges, or by integrally molding or gluing a resin plate.

Filtration performance test example Regarding the filter material of the present invention and the conventional filter material B, JIS-
The results of the filtration performance test described in D1611 are shown in FIG.

At this time, the effective filtration area of the filter material was 1000 C11, the flow rate (2) was 10 ρ/min, and the oil temperature was 80°C.

As is clear from FIG. 6, the filter medium of the present invention can gradually increase the pressure loss caused by dust capture in the fluid to be filtered without any change in filtration efficiency, further extending the life of the filter medium. can be improved.

(Effects of the Invention) The filter medium of the present invention has at least three stages of density change in the plane direction of the filter medium, so it is highly effective in sieving out dust and the filter medium is improved by trapping dust. It can progress the clogging in stages, and is excellent in both filtration performance and long life.

[Brief explanation of drawings]

FIGS. 1 to 5 are conceptual diagrams of cross-sections of filter media according to fruit examples of the present invention, and FIG. 6 is a graph showing test results of filtration performance. 1... Base material, 2... Pores, 3... Raised. −8=

Claims (1)

[Scope of Claims] 1. A filtering material having a density gradient in the surface direction of the filtering material, the density gradient being formed by density changes in at least three stages. 2. The filter material according to claim 1, wherein the density change in the surface direction is formed in a lattice pattern. 3. The filter material according to claim 1, wherein a raised layer is formed on the surface of the filter material on the upstream side of the flow of the fluid to be filtered.