JPH04358509A - Drum filter type filter device - Google Patents

Abstract

PURPOSE:To provide a device of simple structure with good filtering power by attaching a nozzle means for generating the stock solution flow reverse to the rotating direction of a stream along a curved flow path starting from a filter terminal point at an inflow inlet of stock solution. CONSTITUTION:A curved flow path 22 is formed along the peripheral face of a drum filter 28 at the bottom face of a treatment tank 21. An inflow inlet 15 of stock solution is formed in communication with the curved flow path 22 in the vicinity of a filter terminal point A. A nozzle means 23 for generating the flow of stock solution reverse to the rotating direction of a drum 28 along the curved flow path 22 starting the filter terminal point A is attached under a stock solution inflow inlet 25. A solid floatation material in the stock solution can be easily caught when passing through the opening of the filter 28 by said arrangement, and in addition the stock solution flowed in from the nozzle means 23 is guided first to an area below the filtrate level where adhesion force (suction force) is highest. A secondary flow along the curved flow path 22 starting from the point A is generated by the flow from the nozzle means 23 and fine solid floatation materials not adhering in the vicinity of point A and remaining as they are can be carried along the flow path 22.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a filtration treatment device for filtering solid suspended matter such as sludge, sludge, pulp stock solution, etc. containing pulp fibers using a drum-shaped filter that rotates. Drum filter type filtration processing that has processing ability and eliminates the accumulation of fine suspended matter including short pulp fibers at the filtration end point where the drum filter desorbs from the surface of the raw solution to above the liquid surface, which has been a problem in the past. It is related to the device.

0002

2. Description of the Related Art FIG. 4 is an explanatory diagram showing the structure of a conventional drum filter type filtration processing apparatus. As shown in the figure, the processing tank 1 has a raw water inflow chamber 3 divided by a weir plate 2, a liquid level detection chamber 4 and a liquid level detector 16 connected to each other by a conduit. The height of the weir plate 2 is adjusted to maintain a higher liquid level than in the processing tank 1, and the raw water sent from the inlet 5 is supplied to the separation filter 6 over the top of the weir plate 2. First, solid suspended matter in the liquid is separated into coarse and fine particles. Fine suspended matter containing short pulp fibers passes through the separation filter 6, collides with the baffle plate 7, and is sent into the processing tank 1, while coarse suspended matter containing coarse fibers passes through the separation filter 6 and is sent directly to the drum. It is sent onto filter 8.

[0003] This drum filter 8 has a wire mesh with a large mesh formed on its circumferential surface, and is driven and rotated by a motor 10. Therefore, the above-mentioned coarse suspended matter such as coarse fibers is filtered by the drum filter 8, and the filtered treated water 11 is taken out from the opening 12 of the take-out pipe and is reused or discharged. Note that a shower 9 is provided inside the separation filter 6.
This prevents the filter 6 from clogging.

[0004] Fine suspended matter containing pulp short fibers that could not be removed by the separation filter 6 is removed from the treatment tank 1 by a partition plate 1.
The partition plate 13 is curved along the circumferential surface of the drum filter 8, and is attached to the metal surface of the drum filter 8 while floating at the end of the partition plate 13. It helps to average the concentration of raw water within 1 and increase the filtration efficiency. Then, oil and the like in the raw water adhere to the drum filter 8 near the liquid surface.

As mentioned above, since the wire mesh of the drum filter 8 has a large mesh size, the degree of adhesion is high at first, and the coarse pulp, coarse particles, etc. that were previously separated by the separation filter 6 could not be separated thereon. Short pulp fibers, fine particles, etc., and finally oil, etc. adhere, forming three layers on the surface of the filter 8.

Pulp and the like adhering to the outer peripheral surface of the drum filter 8 are transferred to the peeling roll 14 which is in contact with the drum filter above the water surface and removed from the filter 3. Pulp and the like adhering to the peeling roller 14 are finally removed and recovered by a scraping knife 15 provided at the tip of the roll. As the drum filter 8 rotates, that part of the drum filter 8 from which deposits such as pulp fibers and particles have been removed by contact with the peeling roll 14 enters the raw solution again.

[0007]

[Problems to be Solved by the Invention] As described above, coarse pulp fibers and coarse particles adhere to the peripheral surface of the drum filter 8 that enters the raw solution as it rotates, and then short pulp fibers and fine particles that cannot be separated in advance Particles are attached, and finally suspended matter such as oil is adsorbed to the solid suspended matter containing attached pulp fibers.

However, since floating substances such as pulp fibers in the raw solution adhere to the drum filter circumferential surface due to the water pressure on the drum filter circumferential surface, the area with the highest adhesion force is below the water surface of the treated water. As the drum filter approaches the filtration end point where it separates from the raw solution, the water pressure decreases and the adhesion force (suction force) decreases, causing short pulp fibers and fine suspended matter to remain unattached, or The short pulp fibers and fine suspended matter that had once attached were detached, and a pool of short pulp fibers and fine suspended matter was formed at the end of filtration of the drum.

[0009] Furthermore, solid suspended matter in the stock solution is separated by the separation filter 6 into coarse and fine particles, but the structure of the device is complicated. In addition, as mentioned above, pulp and suspended particulate matter in the stock solution are attached (suctioned) by the water pressure around the drum filter, so the substances separated by the separation filter 6 are sent to the drum filter 8. However, it was once desorbed in the stock solution and then adhered again, which was a problem. Furthermore, there was a problem in that the partition plate 13 and the bottom surface of the processing tank 1 were doubled at the bottom of the processing tank, making cleaning difficult.

[0010] The present invention provides a drum filter type filtration device which has a simple structure, has good processing performance, and is particularly capable of eliminating accumulations of short pulp fibers and fine suspended matter at the end of filtration of the drum. With the goal.

[0011]

[Means for Solving the Problems] In the drum filter type filtration processing apparatus according to the invention as set forth in claim 1, a part of the peripheral filter is disposed in a processing tank that accommodates the stock solution flowing in from the stock solution inlet. A peripheral surface of the drum filter on which the raw solution in the processing tank rotates, comprising a rotationally driven drum filter immersed so as to be exposed from the surface, and a filtrate discharge means for discharging the filtrate inside the drum filter to the outside. In a drum filter type filtration treatment device configured to continuously scrape off filtration residue adhering to the surface of the peripheral filter when passing through the filter at a position above the water surface downstream in the rotational direction of the drum filter, the bottom surface of the treatment tank forms a curved flow path along the circumferential surface of the drum filter, and the stock solution inlet enters the curved flow path at a position near the filtration end point where the drum filter is detached from the surface of the stock solution above the liquid surface. The undiluted solution inlet is provided with a nozzle means for generating a flow of the undiluted solution from the filtration end point along the curved flow path in a direction opposite to the rotational direction of the drum.

More preferably, the nozzle means includes a variable nozzle that changes the cross-sectional area of the nozzle opening depending on the water head.

[0013]

[Function] In the present invention, the shape, arrangement, rotation direction of the drum, etc. of the conventional drum filter type filtration processing device are changed in various ways to achieve good processing performance with a simple structure. When we sought a configuration to eliminate the accumulation of short pulp fibers and fine suspended matter at the end point, we found that the bottom of the treatment tank forms a curved flow path along the circumference of the drum filter; Provided in communication with the curved channel at a position near the filtration end point where the undiluted solution is desorbed from the surface of the undiluted solution above the liquid surface; The best results were obtained with a nozzle means that produced a flow of the stock solution in the opposite direction.

That is, a flow occurs in the raw solution flow path in the opposite direction to the rotational direction of the drum from the filtration end point. On the other hand, the drum is rotated in a direction opposite to the flow of the stock solution channel. For this reason, pulp fibers and suspended matter in the stock solution are likely to get caught in the filter pores when passing through them, and in addition, the adhesion (suction power) of pulp fibers and suspended matter in the stock solution increases.
Since the raw solution flowing from the nozzle means is guided to the region below the surface of the treated water where the .

[0015] Also, from the filtration end point, a side stream is generated in the same direction as the rotational direction of the drum, and pulp short fibers and fine suspended matter remaining without being attached near the filtration end point are removed from the drum. The filter is carried along a curved flow path in the direction of the filtration start point where the filter begins to be immersed from above the surface of the stock solution to the surface of the stock solution,
Filtration can be performed again using a filter to which coarse pulp fibers and coarse suspended matter have adhered, and accumulation of short pulp fibers and fine suspended matter at the end of filtration can be eliminated.

More preferably, when the nozzle means includes a variable nozzle that changes the nozzle opening cross-sectional area according to the water head, the opening cross-sectional area of the variable nozzle can be adjusted according to the water head caused by the inflow pressure of the stock solution or the change in the water level of the stock solution. Since the flow rate changes, the inflow amount and inflow speed can be changed, operation can be performed under optimal operating conditions, and a wide range of stock solution compositions can be accommodated. In the examples described later, the variable nozzle is a plate nozzle having a metal plate spring mechanism, but other mechanisms include:
A mechanism may be used in which the plate nozzle is provided with an opening/closing means so that an arbitrary opening cross-sectional area can be set.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing the structure of an embodiment of the present invention. FIG. 2 is an explanatory diagram showing the configuration of another embodiment of the present invention. FIG. 3 is an explanatory diagram showing the internal configuration of the processing tank. In FIG. 1, FIG. 2, and FIG. 3, the same reference numerals indicate the same or corresponding parts.

As shown in each figure, a drum filter 28 in which a part of a wire mesh filter with a large mesh degree is immersed on the circumferential surface is installed in the processing tank 21 that holds the stock solution 20 that has flowed in from the stock solution inlet 25. It is installed so as to be rotated in the direction of the arrow by a motor 30. drum filter 2
A filtrate discharge port 32 is provided inside the filter 8, and the treated water 31 that has passed through the filter is temporarily transferred to maintain the treated water level lower than the liquid level of the stock solution 20.

The bottom and inner surfaces of the processing tank 21 are curved along the circumferential surface of the drum filter 28 to form a curved flow path 22 composed of the curved surface 26 of the processing tank 21 and the circumferential surface of the drum filter 28. do. In addition, a conduit 27 is connected to the processing tank 21.
It has a liquid level detection tube 24 connected with.

The raw solution inlet 25 is connected to a drum filter 28.
A metal plate nozzle 23 is formed on the wall surface of the processing tank 21 in the vicinity of the filtration end point A, which is the point at which the undiluted solution is desorbed from the undiluted solution surface above the liquid surface, and covers the upper part of this undiluted solution inlet 25 and extends downward.
is removably provided along almost the entire length of the processing tank 21 in the longitudinal direction. This plate nozzle 23 is configured in the shape of a plate spring whose opening cross-sectional area changes according to the water head generated by the inflow pressure of the stock solution or the change in the water level of the stock solution. In addition, there are several air vents 37 at the top of the plate nozzle 23.
is provided so that if air accumulates inside the plate nozzle 23, it can be removed here. Since the plate nozzle 23 is formed over almost the entire length in the longitudinal direction of the processing tank 21, it is possible to uniformly supply the stock solution to the drum filter 28, and the solid suspended matter adhering to the drum filter 28 becomes uniform. Peeling onto a peeling roll 34, which will be described later, can be performed satisfactorily.

By the way, in the drum filter 28, since the adhesion force (suction force) of deposits is due to the pressure difference between the inside and outside of the drum, the region with the highest adhesion force (suction force) is the liquid of the treated water inside the drum. The area is below the surface. In this device, raw water 20 sent from an inlet 25 is guided downward by a plate nozzle 23. The undiluted solution led downward is processed into treatment tank 2.
The liquid flows along one curved curved channel 22 and is guided toward a filtration start point B, which is the point where the drum filter 28 starts to be immersed in the raw liquid surface 20 from above the raw liquid. That is, since the stock solution discharged from the plate nozzle 23 first passes through the area where the adhesion force (suction force) is highest as described above, the pulp of coarse fibers, coarse suspended matter, pulp short fibers, and fine suspended matter in the stock solution are removed. etc., solid suspended matter adheres efficiently.

The raw solution with most of the solid suspended matter attached and removed reaches the vicinity of the filtration start point B, where the coarse fiber pulp and coarse suspended matter are first filtered through the mesh of the drum filter 28 with a large mesh degree. It adheres to the filter and reduces the mesh size of the filter. After this, short pulp fibers and fine suspended matter adhere to the filter. The drum filter 28 that has passed the region where the adhesion force (suction force) is the highest is the filtration end point A.
The undiluted solution reaches the surface of the water.

Solid suspended matter such as pulp adhering to the outer peripheral surface of the drum filter 28 is transferred to the peeling roll 34 that is in contact with the drum filter on the water surface and is removed from the drum filter 28. and peeling roll 34
Solid floating matter such as pulp adhering to the roll is removed by a scraping knife 35 provided at the tip of the roll and discharged from the receiving doctor 33. As the drum filter 28 rotates, that portion of the drum filter 28 from which deposits such as pulp fibers and particles have been removed by contact with the stripping roll 34 enters the raw solution again. A shower 29 is provided above the drum filter 28, and the drum filter 28
prevent clogging.

By the way, as mentioned above, the adhesion force of pulp fibers and suspended matter in the raw solution on the peripheral surface of the drum filter 28 is due to the pressure difference between the inside and outside of the drum, so the area with the highest adhesion force is the treated water. As the drum filter approaches the filtration end point A where it separates from the stock solution, the water pressure decreases and the adhesion (suction force) decreases.
Pulp short fibers and fine suspended matter may remain unattached, or pulp short fibers and fine suspended matter once attached may be detached, and pulp short fibers and fine suspended matter may be removed at the filtration end point A of the drum filter 28. Although a pool is formed, the plate nozzle 23
The water flow guided downward by the drum filter generates a side flow along the same direction, and the drum filter removes pulp short fibers and fine suspended matter that remain unattached near the filtration end point A from above the undiluted liquid surface to the undiluted solution surface. It can be carried along a curved flow path in the direction of the filtration start point where it begins to be immersed, and then filtered again through a filter to which coarse pulp fibers and coarse suspended matter are attached. can be resolved.

Furthermore, since the plate nozzle 23 is removable and there is no special protrusion or double coating inside the processing tank 21,
Cleaning of the processing tank 21 has become easier. When changing the collection of solid suspended solids for each lot of stock solution, it is easy to dispose of the previous stock solution and wash it, and even if the stock solution of a new lot is introduced and processed, the solid suspended solids of the previous stock solution can be removed. It also has the feature of not being contaminated. In addition, the amount of adhesion increases and the drum filter 28
When the filtration capacity of the processing tank 11 decreases, the liquid level in the processing tank 11 rises, so this liquid level is checked by the liquid level detection chamber 14 and the detector 36,
This result is sent to the motor 20 and the drum filter 28
Adjust the rotation speed. In addition, the plate nozzle with a plate spring mechanism changes the opening cross-sectional area of the variable nozzle in accordance with the inflow pressure of the undiluted solution and the water head caused by changes in the undiluted solution water level, so the inflow volume and speed can be changed to achieve optimal operation. It can be operated under various conditions and can handle a wide range of stock solution compositions.

[0026]

[Effects of the Invention] As explained above, in the present invention, the bottom surface of the processing tank forms a curved flow path along the circumferential surface of the drum filter; Provided in communication with the curved flow path at a position near the filtration end point where desorption occurs; the stock solution inlet is provided with a flow of the stock solution from the filtration end point along the curved flow path in a direction opposite to the rotational direction of the drum. Since the filter is equipped with a nozzle means that generates Since the raw solution flowing from the nozzle means is guided to the area below the surface of the treated water, where the adhesion force (suction force) of objects is highest, efficient adhesion can be achieved, and the simple structure makes it easy to use. processing performance can be obtained.

[0027] Further, from the filtration end point, a side stream is generated in the same direction as the rotation direction of the drum, and pulp short fibers and fine suspended matter remaining without being attached near the filtration end point are removed from the drum. The filter is carried along a curved flow path in the direction of the filtration start point where the filter begins to be immersed from above the surface of the stock solution to the surface of the stock solution,
It is possible to perform filtration again using a filter to which coarse pulp fibers and coarse suspended matter have adhered, and there is an effect that accumulation of short pulp fibers and fine suspended matter at the end of filtration can be eliminated.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the configuration of another embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the internal configuration of the processing tank shown in FIG. 1 or 2. FIG.

FIG. 4 is an explanatory diagram showing the configuration of a conventional drum filter type filtration processing device.

[Explanation of symbols]

Claims (2)

[Claims] 1. A rotatably driven drum filter immersed in a processing tank containing a raw solution flowing in from a raw solution inlet so that a part of the peripheral filter is exposed from the surface of the raw solution, and and a filtrate discharge means for discharging the filtrate to the outside, when the raw solution in the treatment tank passes through the peripheral filter of the rotating drum filter, the filter residue attached to the surface of the peripheral filter is removed in the rotation direction of the drum filter. In a drum filter type filtration treatment device configured to continuously scrape water at a downstream position above the water surface,
The bottom surface of the processing tank forms a curved flow path along the circumferential surface of the drum filter, and the stock solution inlet is located at a position near the filtration end point where the drum filter is detached from the surface of the stock solution above the liquid surface. A nozzle means is provided in communication with the curved channel, and the stock solution inlet is provided with a nozzle means for generating a flow of the stock solution from the filtration end point along the curved channel in a direction opposite to the rotational direction of the drum. A drum filter type filtration device characterized by: 2. The drum filter type filtration treatment apparatus according to claim 1, wherein the nozzle means includes a variable nozzle that changes a nozzle opening cross-sectional area according to the water head. .