JPH03137904A - Adsorption filter - Google Patents

Abstract

PURPOSE:To permit the quantity of liq. flow to be increased by dispersively attaching the fine particles of an adsorption substance to the porous wall of a filter medium having pores extending through its cross section. CONSTITUTION:The fine particles 14 of diatomaceous earth or the like capable of adsorbing the superfine particles of graphite contained in a liq. are dispersively attached to a porous filter medium 12 having a number of pores 10 through which the liq. can be based. The filter medium 12 is an aggregate of fibers, between each of which voids 10 exist to permit the passage of the liq. there- through. The fine particles 14 dispersively attached to each fiber adsorb the superfine particles contained as contaminant in the liq. passing through the filter medium to obtain a clean liq. This permits a reduction in the size and cost of a filter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adsorption filter capable of adsorbing and removing fine particles mixed in a liquid. Therefore, for example, graphite fine particles of a graphite electrode in electric discharge machining have a particle size of about 0.1 to 0.5 μm, and can be used as a filter for machining fluid mixed with graphite fine particles.

(Prior Art) Conventionally, there is a precipitation method as one of the methods for removing fine particles from a liquid. In this method, a liquid containing fine particles is left in an apparatus for several hours to several days, and the fine particles are allowed to precipitate during this period. There are also centrifugal separation methods that utilize centrifugal force. However, if the size of the particles is less than about 1 μm, in the former method, each particle undergoes Brownian motion based on the movement of liquid molecules, and does not settle permanently. Nor can they be separated by the latter method.

Therefore, a layer of an adsorbent material such as activated carbon that has the ability to adsorb fine particles is sometimes formed on the surface of a fibrous filter element and used as a filter.

Further, Japanese Utility Model Publication No. 61-5926 discloses a high-density adsorption filter made of wound and laminated fibrous activated carbon yarns.

[Problem to be solved by the invention]

However, in filters with a layer of adsorbent material formed on the surface of the element, particles can only be adsorbed on the surface, so it is necessary to use a filter with a fine mesh. difficult to do. Moreover, clogging occurs after a small amount of liquid has been filtered, and the filter is likely to become unusable. If an attempt is made to increase the flow rate, the entire device will become larger.

Furthermore, in the method of using yarns of fibrous activated carbon, such fibrous activated carbon cannot be said to be inexpensive, and there are problems in terms of cost.

Therefore, in order to solve this problem, the present invention aims to provide an inexpensive adsorption filter for ultrafine particles that can increase the flow rate even if it is small and can be used for a long time without clogging. .

[Means for Solving the Problems] In view of the above object, the present invention provides a filter comprising a porous filter medium and an adsorbent material, in which fine particles of the adsorbent material extend to the inside of the cross section of the filter medium. Dispersed in the porous pore walls,
To provide an adsorption filter characterized by adhesion.

[For production]

Adsorbed fine particles are dispersed and attached to the pore walls throughout the cross section of the porous filter medium, so while the liquid mixed with ultrafine particles such as graphite passes through the filter medium through the porous pores,
The fine particles of the adsorbent adhering to the pore walls adsorb the ultrafine particles, and perform a liquid filtration action not only on the surface of the filter medium but also inside the filter medium.

Therefore, a considerable amount of liquid can be filtered before clogging occurs and the filter becomes unusable, and since the liquid passes through the pores of the filter medium, a large flow rate can be achieved.

〔Example〕

The present invention will be described in more detail below based on embodiments shown in the accompanying drawings. FIG. 1 is an enlarged partial sectional view of a filter according to the present invention, in which ultrafine particles such as graphite mixed in the liquid are inserted into a porous filter medium 12 having a large number of holes 10 through which the liquid to be filtered can pass. This diagram schematically shows how fine particles 14 of diatomaceous earth or the like having adsorption characteristics are dispersed and attached. The filter medium 12 is an aggregate of fibers, and is made of a nonwoven fabric, a thread-wound layered body, or the like.

In such an aggregate of fibers, there are voids (used interchangeably with pores) 10 between each fiber, and these voids 10 allow liquid to pass through, and fine particles of diatomaceous earth 14 are dispersed in each fiber.
Because it is attached, it adsorbs ultrafine particles as dust components mixed into the passing liquid, thereby making it possible to regenerate the liquid cleanly.

FIG. 2 schematically shows a cross section of a conventional filter using diatomaceous earth, in which a carcass made of fine particles 14 of diatomaceous earth is formed only on the surface of a filter medium 12 made of an aggregate of fibers. In this case, as can be inferred from the figure, the filter is easily clogged by dust components in the liquid, and becomes unusable after filtering a small amount of liquid.

Therefore, a work process is required in which fine particles such as diatomaceous earth are dispersed and adhered to the constituent fibers of the filter medium that define the voids 10 inside the filter medium 12. The initial stage of this process is shown in Fig. 3, and the final stage The state is shown in FIG. That is,
A liquid mixed with diatomaceous earth is flowed through the layered filter medium 12 at a low flow rate, and the fine particles of diatomaceous earth are allowed to penetrate and adhere to the inside of the filter medium 12. Since diatomaceous earth has the property of adhering to fibers, it is easy to disperse and adhere to the entire filter medium once it is allowed to penetrate inside.

In addition, at the stage of spinning the fibers 20a to form the yarn 20, a liquid mixed with diatomaceous earth fine particles 14 is sprayed to make the diatomaceous earth fine particles 14 adhere to the inside of the yarn 2 shown in FIG.
0 to form a thread wound body 12' shown in FIG. 6, which can be used as a filter. In addition, in order to make the diatomaceous earth fine particles 14 penetrate into the inside of the thread 20,
This can also be achieved by a method similar to that described in FIGS. 3 and 4 above. In addition, a cylindrical body 12' (see Fig. 8) is a cylindrical body 12' (Fig. ) can also be used as a filter. The cylindrical filter shown in FIGS. 6 and 8 can be easily inserted into a pipe member and provided as a cartridge.

The effect of the filter according to the present invention was tested in comparison with the conventional filter shown in FIG. 2, and the results are shown in FIG. This test is carried out using a circulation pipe in which a 201 processing fluid mixed with 3 cc of ultrafine graphite particles is put into a tank, sucked up by a pump, passed through a filter, and returned to the tank. A pressure gauge was provided just before the filter, and the gauge pressure P supplied to the filter was measured. The conventional type filter has 50 g of diatomaceous earth attached to the surface of the thread-wound element, and the type according to the present invention has the same 50 g of diatomaceous earth dispersed and attached to the pore walls extending into the cross section of the same thread-wound element. I used the same thing.

FIG. 9 shows the supply gauge pressure P on the vertical axis and the elapsed time on the horizontal axis. Line LO is for the conventional type filter, and lines L1 to L5 are for the filter according to the present invention. In this test, it is assumed that the filter has become clogged to the limit of use when the liquid supply gauge pressure P reaches 2.6 kgw/cnl. In the conventional filter, the limit was reached after the elapsed time t was 3 minutes, but in the filter according to the present invention, as shown by the line Ll, the rising slope of the pressure P is considerably smaller than the line LO, and the elapsed time t is 3 minutes. The supply pressure P at the time of 3 minutes is about 0.7 kgw/ca, and the limit pressure is 2.6 k
There is plenty of room until gw/cd.

In addition, in this test, the pressure P hardly increased after the elapsed time t was about 3 minutes, which indicates that the filtration of the liquid by the filter according to the present invention was completed, and the
After a minute has passed, use the same amount of Graphite Ultrafine Particles 3c as before.
c was added to the processing liquid in the tank, and the test was continued. In that case, the pressure increase line is L3, and when the filtration is completed again, it becomes line L4. When the elapsed time reaches 20 minutes, 3 cc of Graphite ultrafine particles are added to the processing fluid again, and the pressure increase line at that time is L5. It is. In this way, the critical supply pressure was reached.

When the conventional filter was used, the supply gauge pressure reached the limit pressure of 2.6 kgw/c4 after 3 minutes, but the liquid in the tank at that time was almost filtered and became transparent. However, if further filtration is to be performed, the filter must be replaced with a new one. Furthermore, when the filter according to the present invention was used, it was almost completely filtered and became transparent after 3 minutes had elapsed, and the machining fluid to which ultrafine graphite particles had been added was also almost filtered and became transparent about 4 minutes after it was added. . Furthermore, after adding ultrafine graphite particles, the supply gauge pressure reached the critical pressure in about 1 minute, and about half of the processing liquid was filtered. In other words, it can be seen that between the conventional filter and the filter according to the present invention, the filter according to the present invention has a filtration ability to trap slightly more than twice as much graphite ultrafine particles.

The filtration filter used in the above test was cut and the adsorption state of graphite inside it was observed under magnification, and the filter according to the present invention was able to adsorb graphite to a greater extent, demonstrating its effectiveness. . Also, before the exam,
The degree of contamination of the processing fluid at the test stage was evaluated using photographs.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the entire volume of the filter filters the liquid, so it can be used for a long time without clogging, and it can be made smaller.Furthermore, since the filter medium is porous, it is possible to filter the liquid. It can provide a large flow rate and is practical. As long as diatomaceous earth is used as the adsorbent, its cost is low, and an inexpensive adsorption filter can be provided.

[Brief explanation of the drawing]

FIG. 1 is an enlarged partial cross-sectional view of a filter according to the present invention, FIG. 2 is a schematic partial cross-sectional view of a conventional filter, and FIG. 3 is a cross-sectional diagram of the filter shown in FIG. 1 at an initial stage of the manufacturing process. Figure 4 is a cross-sectional diagram of the final stage of the manufacturing process of the filter shown in Figure 1. Figure 5 is a diagram of the process of dispersing the adsorbent inside the thread. Figure 6 is a spool using the thread shown in Figure 5. Fig. 7 is a schematic perspective view of a case where an adsorbent substance is dispersed and adsorbed on a band-shaped nonwoven fabric; Fig. 8 is a perspective view of a filter in which the band-shaped nonwoven fabric of Fig. 7 is wound into a roll; FIG. 9 is a graph showing the effect of the filter of the present invention. IO...pore (void), 12...filter medium, 14
...Fine particles of diatomaceous earth, 20...Thread, 22...
Band-shaped non-woven fabric. 12' P (kgW/cm2) Real name map

Claims (1)

[Claims] 1. A filter comprising a porous filter medium and an adsorbent substance, wherein fine particles of the adsorbent substance are dispersed and adhered to the pore walls of the pores extending to the inside of the cross section of the filter medium. An adsorption filter characterized by: 2. The adsorption filter according to claim 1, wherein the porous filter medium is made of fabric. 3. The adsorption filter according to claim 1, wherein the porous filter medium is a thread-wound body. 4. The adsorption filter according to any one of claims 1 to 3, wherein the adsorption substance is made of diatomaceous earth.