JPH0368154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for removing fiber layers from rotating disk filters. The present invention is suitably applied to filters used in the textile industry and paper manufacturing industry.

Disc filters are used in the textile and paper industries for cleaning backflow water and concentrating fiber suspensions. Such filters have a horizontal shaft with an axial passage for discharge at one end of the shaft and a plurality of disc-shaped filter plates mounted radially on the shaft.
Each filter plate consists of several sections, each connected to a respective flow path in the shaft. The filter plate is placed in the trough and immersed in the suspension of fibers to be filtered to about 50%. Said one end of the shaft is usually connected to a pressure reducing tube, a so-called suction head.

When the filter plate is rotating in the trough, the fiber suspension in the trough is filtered through the filter plate by the pressure difference between the fiber suspension in the trough and the inside of the filter. Ru. This pressure difference is created by a pressure drop tube. A fibrous layer is formed on the side of the filter plate that is immersed in the suspension. To obtain continuous treatment, the layer of fibers is removed from the filter plate after it emerges upwardly from the gutter, so that when the filter plate descends back into the gutter it is free of fibers.

The fiber layer can be removed by liquid spraying. The spray loosens the fiber layer at the periphery of the disc filter and the fiber cake falls by gravity onto the screw conveyor. Most of the liquid from the liquid spray falls into the fibrous layer, thereby diluting it with water and resulting in a high moisture content, which is clearly disadvantageous in many cases. One way to prevent this is to use air or compressed air instead of liquid. What is therefore necessary in advance is to maintain the air pressure and amount of air used at reasonable levels. This is because compressed air is a relatively expensive medium in this case. This means, among other things, that the air spray must be placed as close to the filter plate as possible. This is because the effectiveness of the air emitted from the spray decreases primarily inversely as the square of the distance. The difficulty here is that disc filters always have some axial runout around their filter plates. Eliminating this runout would require an unreasonably expensive construction.

A further disadvantage of having compressed air nozzles placed at a relatively large distance from the filter plate and the associated blowing pressure is that fibers from the filter plate can be blown around and deposited on various parts of the filter. There is a risk of interfering with the operation of the equipment.

A solution to the above problem is to allow the nozzle to follow the axial runout around the filter plate.
One solution is described in US Pat. No. 4,131,548. This is intended to pull the slurry-like platelets away from the filter. In order to scrape the cake evenly despite the axial deflection of the filter plates, a sliding shoe to which the scraper is firmly fixed can slide toward a guide rail located approximately around the periphery of each filter plate. forgiven. However, this solution results in considerable wear on the sliding shoes and guide rails and usually results in equipment shutdown due to the formation of filter cake on the guide rails and sliding shoes. The difficulty when using such equipment within the textile and paper industry is that the environment in which it has to operate is characterized by high atmospheric temperatures, corrosive atmospheres with temperatures above 90°C and usually low PH values. That's why it's so troublesome.

The object of the invention is to provide a device for removing the fiber layer by means of a gas and/or liquid spray device, which spray device adds the fiber layer at a close distance in a guaranteed manner; This solves the aforementioned problems regarding operational interference and economy.

A device according to the invention for removing a layer of fibers from a rotating disk filter having a plurality of filter plates mounted side by side on a common axis is provided for removing the fiber layer and located close to the periphery of the disk-shaped filter plates. a gas and/or liquid spraying device for spraying, a sliding shoe fixed relative to the spraying device, and a guiding device positioned around the periphery of the filter disc for guiding said sliding shoe, achieving the above object. For this purpose, the device according to the invention is characterized in that the sliding shoe is arranged with a clearance relative to the guide device and is suspended like a pendulum device.

Considerable advantages over the prior art are achieved by the present invention. The sliding shoe does not slide against the guide except in the case of very extreme run-outs around the circumference of the disc, so that wear and operational problems are largely eliminated. The spray device follows the fiber layer at a very close distance so that the gas or liquid pressure can be kept at a low level. However, perhaps the most essential benefit is that sliding
Even though the relatively large runout around the disc filter exceeds the size of the gap between the sliding shoe and the guide device, the guide will not work except in exceptional cases due to reaction forces acting on the spray device from the air or liquid jet. Do not come into contact with the equipment. These reaction forces are often offset by the fact that the spray device is suspended in a pendulum-like configuration, allowing the distance to the fiber layer to be adjusted in the event of wobbling. By this, the sliding shoe may be more or less superfluous in most cases, but it is used together with the guiding device to ensure that very fast and large circumferential swings are avoided, and unsuitably large sprays. This is to ensure that a distance between the fiber layer and the fiber layer cannot occur.

Tests on known disc filters in use have shown that the stationary spring mouth should be located an average distance of approximately 20 mm to 30 mm laterally from the periphery of the disc filter plate. This has been proven. In this case, the air pressure required to remove the fiber layer was 500-600 kPa. If said spray device were arranged to follow the axial runout around the disk, it would be
It can be placed at a position of ~3 mm, and the required air pressure is approximately 50 kPa. This means that there is a difference in air consumption on the order of 1:10 for the same spray mouth area. Thus, a condition for economical use of gas to remove the fibrous layer is to position the spray device close to the periphery of the disk and regardless of the axial runout of the disk. In order to keep the air consumption at a reasonable level and to avoid the fibers being blown around and causing the disadvantages mentioned above, this distance should not exceed 5 mm, and in a preferred example it should not exceed 3 mm. Must not be. When using liquid as a spray material, there should be a corresponding distance. In the present invention, it is ensured that such distances are maintained when using disc filters.

According to one embodiment of the invention, said spray is located in front of the sliding shoe in the direction of rotation of the filter disc. The sliding surfaces of the guide device can thereby be cleaned before the sliding shoe passes through, eliminating the risk of interference due to deposits on the sliding surfaces. Embodiments of the invention will now be described in more detail with reference to the accompanying drawings.

In FIG. 1, a bracket 2 is attached to a main tube 1 for gas, e.g., air, or for liquid, e.g., water.
is attached, and the spring 3 is preferably a leaf spring and is attached to the bracket. The spring 3 has a movable fixing device for the sliding shoe 4 attached to the opposite end of the spring 3. The sliding shoe is provided with a gap on a guide rail 5 mounted around the periphery of a disc-shaped filter plate 6, and the disc filter has a plurality of such filter plates mounted side by side on a common axis. ing. The spring 3 acts as a pendulum whose lateral movement is limited by the sliding shoe being in contact between the sides of the guide rail 5. Spray nozzles 8 and 9 on each side of the periphery of the filter plate 6 are fixed to the sliding shoe 4, for example, through connecting tubes 7 for the spray material as shown. When the filter plate 6 rotates, it moves in the direction of the axis (arrow). This deflection causes the spray nozzles 8 and 9 to follow this movement. This is mainly due to the recoil from the spray, but
In some cases, the sliding shoe will momentarily move against the guide rail 5.
This is due to the fact that it comes into contact with This pendulum suspension of the sliding shoe and the spray nozzle connected thereto allows the sliding shoe and the spray nozzle to maintain their relative position with respect to the filter plate 6 during rotation thereof. FIG. 1 also shows a tube connection for the spray gas or liquid and an elastic hose 11 between this connection and the tube connection 7 for the spray nozzle.

Figures 2 and 3 show the device of Figure 1 from both sides, with the sliding shoe and spray nozzle suspended as a pendulum, so that the deflection occurs in the direction of the axis of the filter disc. It clearly shows what is possible. In the embodiment shown in FIGS. 1 to 3, suspension is achieved by means of leaf springs 3. When using such a spring, the force of the spring should be small relative to the reaction force from the spray nozzle or the difference between the reaction forces when they are opposed to each other. This is because otherwise the sliding shoe could come into contact with the guide rail for a long time.

4 and 5 show another embodiment of a pendulum suspension, in which the leaf spring of the embodiment of FIGS. 1 to 3 is omitted. A sliding shoe with a spray nozzle is suspended and swings from an elastic hose 11 which serves as a supply means for spray gas or spray liquid. In FIGS. 4 and 5, the sliding shoe and the spray nozzle are combined into one device 12, the sliding shoe having a perforated passage 13 for the spray gas or spray liquid.

FIG. 6 shows a part of the periphery of section 6 of the filter plate in a larger view. The filter plate part is usually made of synthetic wire cloth15
Covered. This cloth 15 has the shape of a so-called cloth bag and covers all parts of the filter plate. This results in a cloth covering the periphery of the filter plate, which also forms a layer of fibers that is usually very difficult to remove. Due to the fact that the guide rail 5 lies on the fabric 15 at its periphery, the layer 16 of fibers adjoining the guide rail 5 can be removed therefrom very easily by means of a jet of gas or liquid from the spray nozzles 8 and 9. This is an advantage. The jet of spray readily penetrates the underside of the fibrous layer to decake from the fabric without the need to penetrate the entire fibrous layer.

FIG. 6 also shows the normal position of the sliding shoe 4 with respect to the guide rail 5. The gap between the sliding shoe and the guide rail is preferably 2 on each side of the guide rail in air spraying.
-3 mm, and 2-5 mm is good for water spray. The axial runout of the filter plate can be larger, but the oscillating suspension of the sliding shoe allows good tracking.

The invention is not limited to the use of only liquids or gases as spray materials. In some cases, the use of mixtures of gases and liquids, such as air and water, has proven to be very effective.

The above describes the implementation of the invention for removing layers of fibers from a filter. Here, the filter cake, due to its content of longitudinally extending substances, has a surprising cohesive strength and cannot be broken down very easily. If a cake attached to such a filter is loosened at one end of the filter, the entire mass will fall under its own weight. Filter cakes produced within the textile and paper industries have such characteristics, but
Similar cakes may also be formed in other technology industries. The invention can also be applied within such fields.

[Brief explanation of drawings]

FIG. 1 is a side view of one preferred embodiment of the invention; FIG. 2 is a view taken in the direction of line - of FIG. 1;
Figure 3 is a view seen in the direction of line - in Figure 1; Figure 4
The figure is a side view of another embodiment; FIG. 5 is a view taken in the direction of the line - in FIG. 4; FIG. 6 is a partially sectional view and an enlarged view taken in the direction of the line - in FIG. It is. In the figure, 4... sliding shoe, 5... guide rail, 6... filter disk, 8, 9... nozzle,
11...Elastic hose.

Claims (1)

[Scope of Claims] 1. An apparatus for removing a fiber layer from a rotating disc filter having a plurality of disc-shaped filter plates mounted side by side on a common shaft, the apparatus comprising: a plurality of filter plates for removing the fiber layer; a gas and/or liquid spray device located close to the periphery of the spray device; a sliding shoe fixed relative to the spray device, with a guide rail located around the periphery of the filter plate for guiding the sliding shoe; A device for removing a fiber layer from a rotary filter plate, wherein the sliding shoe is arranged with a gap with respect to the guide device and suspended by a swinging member. 2. The apparatus according to claim 1, wherein the distance between the gap and the periphery of the filter plate of the spray device is approximately the same size. Device. 3. An apparatus for removing a fiber layer from a rotary filter plate according to claim 1 or 2, wherein the gap is from 2 mm to 5 mm. 4. The device according to any one of the preceding claims, wherein the swinging member includes a spring element. 5. The device according to claim 4, wherein the spring element is a leaf spring. 6. The device according to any one of the preceding claims, characterized in that the rocking member includes an elastic hose for supplying gas and/or liquid to the spray device. More fiber layer removal equipment. 7. The apparatus according to any one of the preceding claims, characterized in that the spray device is located in front of the sliding shoe in the direction of rotation of the filter plate. Layer removal equipment. 8. The device according to any one of claims 1 to 6, characterized in that the spray device and the sliding shoe are integrated into one unit, and a spray passage is provided therein. Fiber layer removal device from the board. 9. Apparatus according to claim 3, wherein the gap is further maintained between 2 mm and 3 mm.