JPS581609B2 - precision filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microfilter for fluids such as liquids and gases.

In a clarifying filter using a metal mesh as a filter medium, if the filtration accuracy is to be improved, the mesh will inevitably become finer.

However, due to the structure of the wire mesh and filter, the following problems (1) to (4) arise as counterbalancing conditions that are difficult to solve, and there is a limit to the refinement of the mesh and therefore the improvement of filtration performance. It's coming.

(1) The finer the wire mesh is made (for example, the higher the performance is from 100 microns to several microns), the greater the resistance to the flow of the filtration stock solution becomes.

Therefore, the pressure applied to the wire mesh increases, but on the other hand, the wire mesh becomes thinner and its pressure resistance decreases.

(2) In order to reinforce the wire mesh, a simple method that can be considered is to stack the wire mesh on top of a reinforcing plate with through holes drilled in its smooth surface.

However, in this case, the wire mesh comes in close contact with the smooth surface and is occluded, reducing the effective filtration area.

Therefore, if you try to have the same area, it is inevitable that you will increase the size.

(3) It becomes difficult and complicated to handle the end face of the wire mesh, assemble it, disassemble it, and prevent leakage of filtrate during operation.

(4) When a configuration that implements a filtration process and a configuration that implements a treatment process using powder, such as deodorization through the adsorption effect of activated carbon, are combined individually, the entire configuration becomes even larger and more complex. .

The present invention has been made in view of these conventional problems, and its main purpose is to provide a precision filter with improved filtration performance.

FIG. 1 is a cross-sectional view of one embodiment of the present invention, and FIG. 2 is a partial cross-sectional view taken along the section line (■--■) shown in FIG.

The precision filter F is used for precision filtering a filtration stock solution that is pumped under pressure of, for example, 200 atmospheres or more, and from the top to the bottom of FIG. The net 2 and another circular flat perforated plate 3 are stacked in this order to form a sandwich-like structure.

These members 1, 2.3 are all made of stainless steel.

The stock solution to be filtered is pumped as indicated by the arrow 4, and the filtrate flows out through the perforated plate 1 upward in FIG.

In order to backwash the microfilter, wash water is pumped from the top to the bottom in the direction opposite to the arrow 4 in FIG.

The perforated plate 1 has sufficient strength to support the filter net 2 which is pressurized by the raw water pumped under high pressure in a flat plate shape and prevent deformation. It has sufficient strength to prevent the filter net 2 from being deformed by the washing water pumped by the filter.

The opening of the mesh of the filter net 2 may be fine, for example, less than 50 microns, and the pore size may be about 0.1 micron to 10 microns.

The plurality of filter nets 2 are stacked so that the weave directions of the filter nets 2 intersect with each other, thereby making the mesh or pore diameter uniform over the entire surface.

The number of laminated filter nets 2 is selected depending on the filtering performance.

The perforated plate 1 is formed with a recess at its center, and the filter net 2 and the perforated plate 3 having a diameter smaller than that of the perforated plate 1 are housed in this recessed part.

The surface of the perforated plate 1 facing the filter screen 2 consists of a support surface 5 that supports the filter screen 2, and a fixing surface 6 that fixes the filter screen 2 together with the perforated plate 3. As shown in FIGS. 6 and 7, it is provided with an annular outer circumferential portion 24 for sealing or multi-stage use.

The filter net support surface 5 supports the portion of the filter net 2 that is to perform the filtration action between it and the filter net support surface 11 formed on another porous plate 3 without deforming it, and for this purpose, the filter net 2 is It is formed in a concave shape so that it can be accommodated, and also has a concentric groove 8 in the circumferential direction.
and radially extending grooves 9 are carved.

At the intersections of these grooves 8 and 9, fluid passage holes 10 that penetrate in the thickness direction of the perforated plate 1 are bored every other in the circumferential direction and the radial direction.

A relatively large number of these grooves 8 and 9 are provided, so that the contact area between the support surface 5 of the perforated plate 1 and the filter screen 2 is small.

Therefore, the filtration surface of the filter net 2 is not blocked, and there is no possibility that the effective filtration area will be reduced or the pressure loss will be undesirably large.

Thus, the support surface 5 functions to uniformly support the entire surface of the filtrate passing through the filter screen 2 by the stock solution flowing in the direction of the arrow 4, and also serves to support the filtrate that has passed through the filter screen 2 to the perforated plate 1. It works to collect liquid evenly into 5.

Double annular projections 17 and 18 surrounding the support surface 5 are provided on the fixed surfaces 6 and 12 of the perforated plate 1 at intervals in the radial direction of the perforated plate 1.

The width of the projections 17,18 tapers towards the top.

Like the perforated plate 1, the perforated plate 3 has a support surface 11 and a fixed surface 12.
A large number of annular grooves 13 and a large number of radial grooves 14 are formed in the support surface 11, and the fluid passage holes 15 are formed in the grooves 1.
3.14 at the intersection.

The fixed surface 12 of the perforated plate 3 is provided with double annular projections 19 and 20 corresponding to the projections 17 and 18.

FIG. 3a is an enlarged sectional view of the vicinity of projection 17.19 of FIG. 2.

FIG. 3b shows the pressure distribution acting on the filter screen 2 by the projections 17,19.

The horizontal axis in FIG. 3b indicates the radial direction of the perforated plates 1 and 3, and the vertical axis indicates the magnitude of the pressure acting on the filter screen 2.

The pressure distribution acting on the filter screen 2 produces a sharp contact pressure distribution over the compression width of the filter screen 2 by the protrusions 17.19, that is, the radial width of the perforated plates 1, 3.

Since the filter net 2 is compressed by such a sharp pressure distribution, liquid leaking from the support surfaces 5, 11 in the left and right directions in FIG. 1 at the compressed portions is effectively prevented.

The fluid passage holes 10, 15 formed in the perforated plates 1, 3 are formed to be larger than the width of the grooves 8, 9; 13, 14, so that the liquid can be smoothly distributed.

The amount of liquid allowed to pass through the fluid passage hole 10.15 is the filter net 2.
is equal to or greater than the flow rate of the effective filtration area, thereby avoiding undesirable pressure losses of the filtrate.

Referring again to FIG. 1, a filter is provided in a portion 23 between an inner wall 21 of the perforated plate 1 in the axial direction that is connected to the protrusion 18 of the perforated plate 1 and an outer wall 22 of the perforated plate 3 that opposes this inner wall 21. The periphery of the net 2 is pinched, and the protrusions 17, 18; 19 of the perforated plates 1, 3
, 20, the filter screen 2 remains compressed and welded in a fluid-tight manner in this section 23.

This welding completely prevents liquid from leaking outward through the fixing surfaces 6, 12 from the portion of the filter screen 2 sandwiched between the supporting surfaces 5, 11.

The upper and lower surfaces of the annular outer circumferential portion 24 of the perforated plate 1 are finished to be parallel and uniformly flat by cutting, polishing, etc. to facilitate sealing or multi-tiering.

The outer periphery 24 has an outer surface 2 formed with fluid passage holes 10.15.
5.26, and therefore serves to distribute liquid in the case of multi-stage formation, which will be described later.

When the outer circumferential portion 24 is formed to have a smooth surface as described above, for example, when the present filter is multi-staged,
This has the great advantage of eliminating the need for packing material.

FIG. 4 is a sectional view of another embodiment of the invention.

In this embodiment, in order to tighten the perforated plates 1a and 3a of the same shape with a large force, bolt holes 28 are drilled to commonly pass through the perforated plates 1a and 3a and the filter screen 2a.
, 3a are integrally screwed together.

These members 1a, 2a, 3a are integrally liquid-tightly welded at the outer circumferential portion 19a of the members 1a, 2a, 3a, and bolts (not shown) inserted through the bolt holes 28 are connected to the perforated plates 1a, 3 shown in the third figure.
A are fastened in a direction close to each other and screwed into a nut.

Rivets may be used in place of this combination of bolts and nuts, or connecting bolts may be used to fasten the multi-stage filters together in the case where the filters shown in the third figure are combined into one unit. good.

FIG. 5 shows yet another embodiment of the invention.

In this embodiment, a protrusion 17 for performing the above-mentioned sealing,
18; In place of 19 and 20, an annular projection 29 and an annular recess 30 that abuts the projection 29 via the filter screen 2b are formed on the perforated plates 1b and 3b, respectively.

The curvature of the outer circumferential surface of the protrusion 29 and the curvature of the inner circumferential surface of the recess 30 are different from each other, so that the contact surface pressure distribution over the compression width of the filter screen 2b can be sharpened, thereby ensuring leakage prevention. It can be prevented.

The perforated plates 1b and 3b may be fastened together by welding,
Alternatively, it may be tightened with a bolt inserted into the bolt hole 31, or may be tightened with an adhesive.

Support surfaces 8, 1 of perforated plates 1, 1a, 1b, 3, 3a, 3b
4 may be formed with a very large number of small irregularities by knurling or the like over the entire surface, so that the support surfaces 9 and 11 support the filter screen 2 at a very large number of points, which reduces the flow resistance of the filtrate. can be made even smaller.

The bottoms of the concave and convex portions formed by knurling or the like communicate in common, and also communicate with the fluid passage holes 10.15.

Instead of the above-mentioned filter net, a porous filter medium such as a ceramic plate or a sintered metal plate may be used, and a filter cloth made of woven fabric or non-woven fabric such as plain weave or twill weave may be used. It may also consist of

FIG. 6 shows an example of the use of the filter F shown in FIG.

The filter F is interposed in the pipe line 40.41 through which the liquid flows,
They are attached by flanges 42, 43 of their conduits 40, 41.

In this way, the present filter 10 can be added to an existing pipe line or the like very easily.

FIG. 7 shows another example of use of the invention.

In this filtration device, the filters F are stacked as a unit in three stages, for example, in order to improve the filtration performance, and mounting aids 44 and 45 are provided on the filtration stock inflow side and the filtrate outflow side, and these members F, 44 and 45 are integrally assembled using bolts or the like.

One of the mounting aids 44 is a disc 44 having a through hole in the center.
a and a short tube 44b communicating with the through hole.
A screw is engraved on the outer periphery of the open end of 4b to facilitate installation.

The other additional auxiliary tool 45 is similarly configured.

As described above, according to the present invention, a flat filter medium such as a filter net is sandwiched by a flat perforated plate, and the peripheral edges of the three members are integrally fixed to each other in a liquid-tight manner. Filtration is performed and leakage of the filter is prevented.

In addition, since the flat perforated plate supports the flat filter medium over the entire surface with a small contact surface, the filter medium is reliably supported without deformation or damage even when the filtration resistance is large, and the effective filtration area is It does not block or undesirably increase liquid pressure losses.

Furthermore, since the present filter can be formed as a flat unit, it can be combined in various ways and can be made into a small block by itself, and has many excellent effects.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a view taken from the section line 1-1 in FIG. 1, with the filter screen 2 omitted. FIG. 3a is an enlarged sectional view along the radial direction of the perforated plates 1, 3 showing the protrusions 17.19 of FIGS. 1 and 2;
FIG. b is a diagram showing the pressure distribution of the protrusions 17 and 19. 4 and 5 are sectional views showing a part of other embodiments of the present invention, FIG. 6 is a front view showing one mode of use of a precision filter according to an embodiment of the invention, and FIG. 7 1 is a cross-sectional view of an example of the use of the present invention when performing multi-stage filtration. 1, 1a, 1b, 3, 3a, 3b... flat perforated plate,
2, 2a, 2b... filter net, 5... support surface, 6...
Fixed surface, 8, 9, 13, 14... Groove, 10.15...
-Fluid passage hole, 17, 18, 19, 20, 29...Seal protrusion, 30...Seal recess.

Claims (1)

[Scope of Claims] 1. A flat filter medium having a pore diameter of less than 50 microns for performing precision filtration, and a pair of flat perforated plates sandwiching the filter medium from both sides and reinforcing it by sandwiching the filter medium, comprising: The perforated plate has a filter medium support surface that faces the filter medium and a fixed surface that surrounds the filter medium support surface, and the filter medium support surface has pores that are larger than the diameter of the pores that penetrate in the thickness direction of the perforated plate. A large fluid passage hole is bored therein, the bottom thereof is in common communication, and unevenness communicating with the fluid passage hole is formed over the entire surface of the filter medium supporting surface, and the fixing surface of either one of the perforated plates A seal protrusion is formed in an annular shape, the width of which tapers toward the top, and the seal protrusion is in contact with the protrusion via the filter medium and is provided on the other fixing surface of the perforated plate. An annular seal contact area is formed that produces a sharp contact pressure distribution over the compressed width of the filter medium and effectively prevents leakage.
A precision filter comprising: such a perforated plate; and means for integrally fixing the filter medium and the perforated plate.