JP2001070718A - Filter medium of disk filter machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the strength of a filter plate, to prevent the damage of the filter plate caused by high squeezing pressure and to easily attach and detach the filter plate by constituting the filter plate of a metal disk filter medium wherein a wedge wire screen and an annular support frame having radial ribs are integrally bonded. SOLUTION: In a filter machine wherein a filter chamber is formed from two disk-shaped filter plates 1, 1 and an outer peripheral ring and a freely rotatable impeller is arranged in the filter chamber, each of the filter plates 1 is constituted of a metal disk filter medium wherein a wedge wire screen and an annular support frame 6 having radial ribs 5 are integrally bonded and increased in strength and not damaged by high squeezing pressure and suitable for obtaining a cake low in water content. This filter plate also becomes easy to attach and is convenient from an aspect of maintenance and control. The wedge wire screen consists of horizontally arranged wedge wires and support rods 3 vertically arranged in order to fix the wedge wires and the mesh size of the wedge wire screen is 100-200 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter medium for filtering hard-to-filter sludge such as sewage sludge, and more particularly to an improvement in a filter medium for a disk filter in which an impeller is provided in a filtration chamber.

[0002]

2. Description of the Related Art Conventionally, as a filter medium of a disk filter, a thin punching metal having a hole having a diameter of 0.25 mm to 0.5 mm is mounted in a disk frame in which a punching plate is reinforced. Further, as a filter medium used in the dehydrator, for example, as described in JP-A-6-233906, a filter wire having a flat surface and a fixed cross section is fixed to a non-square plate-like body, A filter medium having many linear slits is known. Also, as described in JP-A-6-210114, a wedge wire screen in which a continuous slit of a V-shaped opening is formed between each wire in parallel with a wedge wire is well known.

[0003]

However, in such a conventional metal filter medium, when concentrated sludge such as sewage sludge is condensed with a polymer and filtered, a part of solid matter that has come out of a hole in the filter medium is removed. The filtrate remained in the reinforcing disc frame, the flow of the filtrate became poor, the filtration was hindered, and the frequency of washing the filter medium was increased. Further, such a metal filter medium cannot be applied with high pressure due to insufficient strength, and when squeezing sludge containing inorganic substances, it is quickly worn and damaged. In addition, there is a problem that the replacement of the filter medium in the case of breakage requires a great deal of labor and time.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and a filter chamber is formed by two disc-shaped filter plates and an outer peripheral ring. In the filter provided with a rotatable impeller in the chamber, the filter plate is a metal disk filter medium in which a wedge wire screen and an annular support frame having radial ribs are joined and integrated. The wedge wire screen is composed of horizontally aligned wedge wires and vertically aligned support rods for fixing the wedge wires, and the aperture of the wedge wire screen is 100 μm.
To 200 μm.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The filter medium of the disk filter according to the present invention is constructed as described above, and a filter plate forming a filtration chamber is integrally joined to a wedge wire screen and an annular support frame having radial ribs. By doing so, the strength is increased, there is no breakage even under high pressure, and a cake with a low moisture content can be obtained. And the installation of the filter media becomes easy,
This is convenient for maintenance. In addition, the wedge wire screen arranges the wedge wires in a horizontal line,
Since the support rods that fix the wedge wires are arranged in parallel in the vertical direction, the pool of the filtrate and some solid matter is reduced,
The frequency of washing the filter medium is low.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter medium of a disk filter according to the present invention will be described in detail with reference to the drawings.
Is a filter plate made of a pair of metal disc filter media. The filter plate 1 has a wedge wire screen 4 in which a large number of support rods 3 are fixed vertically from a back surface to a large number of wedge wires 2 arranged in parallel in a horizontal direction. The annular support frame 6 having the radial ribs 5 is joined and integrated. The solid material that has passed through together with the filtrate in the horizontal slit of the wedge wire 2 is washed away with the filtrate flowing down along the vertical slit of the support rod 3 on the back side. There is no accumulation of filtrate and solid matter in the eyes, and the frequency of washing the filter medium is reduced. As shown in FIG. 3, the pair of filter plates 1 and 1 have outer peripheral ends connected to an outer peripheral ring 7 and inner peripheral outer walls connected to a pair of inner ring support cylinders 8 and 8 to form an annular filtration plate. The room 9 is composed,
The attachment and detachment of the filter plate 1 are facilitated.

[0007] A support cylinder 10 is connected to the inner ring support cylinder 8, and as shown in FIG.
10 is supported on the frames 12, 12 via bearings 11, 11. A drive shaft 13 is inserted through the inside of the support cylinder 10, and a drive pulley 14 fitted to one end of the drive shaft 13 is operatively connected to a drive device 15. A supply path 16 for the stock solution is provided inside the drive shaft 13, and a plurality of supply ports 17 communicating with the filtration chamber 9 are opened on the peripheral surface of the drive shaft 13. Between the filtration chamber 9 and the drive shaft 13, a stock solution supply chamber 18 surrounded by the inner ring support tube 8 and the support tube 10 is formed. An undiluted supply pipe 20 is connected to one end of the drive shaft 13 via a universal joint 19, and the supply pipe 20 is connected to the supply pump 2.
The sludge tank 22 is connected to the sludge tank 22 through a plurality of feed ports 1 of the drive shaft 13.
7, the sludge flows into the undiluted solution supply chamber 18, and the sludge is uniformly pressed into the filtration chamber 9 from the undiluted solution supply chamber 18.

[0008] As shown in FIGS. 3 and 5,
An impeller 23 is supported on a drive shaft 13 inserted into the inside of the support cylinder 10, a side edge of the impeller 23 is brought close to the filter plate 1, and a tip end thereof is retreated backward in the rotation direction. The drive unit 15 is operated to rotate the impeller 23 in the filtration chamber 9. In the embodiment of the present invention, the impeller 23a of the impeller 23 is bent into four straight pieces to approximate a curved line, and the impeller 23 having six blades is disposed in the filtration chamber 9. It is set up. As described above, if the blade 23a is bent into a straight piece to approximate a curved line, the manufacture becomes easy. The reinforcing plate 2 is vertically arranged along the center of the blade surface on the blade 23a on the rear side in the rotation direction of the impeller 23.
4 is fixed. The height of the reinforcing plate 24 is gradually reduced from the boss 23b toward the tip of the blade 23a as a reinforcing rib disposed on the back side in the rotation direction of the blade 23a. Is minimized.

As shown in FIG. 6, a cake outlet 25 is provided in the outer peripheral ring 7 at the periphery of the filtration chamber 9.
A back pressure adjusting valve 26 disposed in 5 is operated by operating a cylinder 27 to apply a back pressure to the filtration chamber 9. Reference numeral 28 denotes a cake chute provided in the outlet 25, and reference numeral 29 denotes a cake chute.
Filtrate receiving trough, reference numeral 30 denotes a washing tube of the filter plate 1, reference numeral 3
Reference numeral 1 denotes a cover for preventing scattering of washing water or the like.

The apparatus according to the present invention is configured as described above, and the opening of the wedge wire screen 4 of the filter plate 1 is set in a range of 100 μm to 200 μm.
When sludge is supplied from the supply path 16 of the drive shaft 13 to the center of the filtration chamber 9 at a press-fit pressure of 0.1 to 0.7 kg / cm 2 while the impeller 23 is rotated at a low speed of 0.1 to 1.0 rpm, The sludge is pressed and conveyed toward the outer periphery in response to the pressing force of the sludge and the pressing force of the rotation of the impeller 23, and moisture is separated by the wedge wire screens 4 of the filter plates 1 on the left and right sides. In the vicinity of the shaft center immediately after the press-fitting, the sludge is concentrated mainly by the press-fitting pressure, and the impeller 23 presses the sludge with a force that overcomes the sliding friction resistance between the concentrated sludge and the filter plate 1,
The sludge applies a shearing action to the cake that bends and moves due to the press-fitting pressure and the rotating action force of the blades 23a. Then, the dewatered cake can be taken out while applying the back pressure by the back pressure adjusting valve 26 of the outlet 25. Since the side surface of the blade 23a of the impeller 23 rotates close to the inner surface of the filter plate 1, the filter plate 1 is rotated. Can be operated continuously without clogging. The results of a dehydration test conducted on sewage-mixed raw sludge (solid matter concentration: 1.59% W / V) agglomerated with a polymer showed that the cake moisture content was 78.7% and the SS recovery rate was 98.1%, which was good. . That is, the opening of the wedge wire screen 4 was set to 100 μm based on the injection pressure of the stock solution and the rotation speed of the impeller.
If it is set in the range from 200 μm to 200 μm, a cake having a low water content and a filtrate having a low solid content can be obtained.

[0011]

As is apparent from the above description, the filter medium of the disk filter according to the present invention is constituted as described above.
Since the filter plate is a metal disk filter material that integrates and integrates a wedge wire screen and an annular support frame with radial ribs, the strength is increased and there is no breakage even under high pressure, making it easy to install and remove the filter plate. Things. The wedge wire screen is composed of horizontally aligned wedge wires and vertically aligned support rods for fixing the wedge wires. Since the solid matter is washed away by the filtrate flowing down along the slits of the support rod on the back side, there is no accumulation of the filtrate and the solids in the slits, and the frequency of washing the filter medium is reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a wedge wire screen.

FIG. 2 is a rear view of a filter plate in which a wedge wire screen is fitted into an annular support frame.

FIG. 3 is a vertical sectional side view of a main part in which a filtration chamber according to the present invention is held on a drive shaft.

FIG. 4 is a longitudinal sectional side view of a disk filter using the filter medium according to the present invention.

FIG. 5 is a front view of an impeller disposed in the disk filter;

FIG. 6 is a vertical sectional front view of a disk filter using the filter medium according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration plate 2 Wedge wire 3 Support rod 4 Wedge wire screen 5 Radial rib 6 Ring support frame 7 Outer ring 9 Filtration chamber 23 Impeller

Claims (3)

[Claims] 1. A filter chamber (9) is formed by two disc-shaped filter plates (1, 1) and an outer peripheral ring (7).
The filter plate (1) has a wedge wire screen (4) and an annular support frame (6) having radial ribs (5) joined and integrated in a filter provided with a rotatable impeller (23). A filter medium for a disk filter, comprising a metal disk filter medium. 2. The wedge wire screen (4).
2. A filter medium for a disk filter according to claim 1, wherein the filter medium comprises a horizontally parallel wedge wire (2) and a vertically parallel support rod (3) for fixing the wedge wire (2). . 3. The wedge wire screen (4).
3. The filter medium for a disk filter according to claim 1, wherein the mesh size of the filter is in a range of 100 μm to 200 μm.