JPH0714397Y2 - Foreign substance separation device in pulp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a device for separating and removing fine foreign matter made of plastic, rubber or the like mixed in pulp.

(Prior Art) Generally, various foreign substances are contained in wood chips, which are raw materials of pulp, and in particular, artificial foreign substances such as plastics and rubber have been increasing in recent years. Then, these foreign substances such as plastics and rubber are finely pulverized in the pulp manufacturing process or the like and mixed into the pulp, which may cause troubles in the subsequent paper making process or significantly deteriorate the paper quality. Is desired.

Conventionally, as a means for separating and removing foreign matter from pulp, a flotation separation method, which utilizes the difference in specific gravity between pulp and lightweight foreign matter such as plastic or rubber, has been widely used. This is a method in which the pulp slurry is introduced into a horizontally long separation tank from one end side, the lightweight foreign matter is floated in the process of the slurry flowing to the other end side, and the pulp is allowed to settle, and the separated two are separately discharged from the tank. is there. The applicant has implemented a foreign matter separating device capable of significantly increasing both the foreign matter removal efficiency and the processing speed by providing an extruding tool that pushes the sedimented pulp after the floating separation of the lightweight foreign matter to the discharge side in such a floating separation system. It was realized as Kosho 59-40438 (utility model registration No. 1601212).

(Problems to be solved by the invention) However, even with the above-mentioned foreign matter separating device, the removal efficiency of light weight foreign matter is about 90%, and higher removal efficiency is demanded from the recent tendency of increasing lightweight foreign matter, while pulp manufacturing With the introduction of the oxygen delignification method, the screen process is being replaced by a closed system, and it is no longer possible to apply a long separation tank to the closed system. Further, in the conventional separation tank, the required foreign matter separation efficiency could not be achieved unless the pulp concentration was diluted to 0.1% or less.

In view of the above circumstances, the present invention has an object to provide a foreign matter separating device that can achieve extremely high lightweight foreign matter removal efficiency and is excellent in applicability to a closed system.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the apparatus for separating foreign matter in pulp according to the present invention has an overflow port forming a selected pulp take-out section at the peripheral portion of the upper portion of a vertical cylindrical tank. In addition to the above, an overflow port is provided in the center of the upper part of the tank to form a lightweight foreign matter extraction part, and an inlet pipe for pulp slurry and dilution water is provided in the side plate part of the tank in the direction of introduction of at least one of the liquids. The configuration is adopted in which the connection is made in a substantially tangential direction with respect to the cylindrical shape.

Further, according to the present invention, in the separating device, a baffle plate for diverting the liquid flow from the overflow port is provided in the vicinity of the overflow port in the peripheral portion, and the circulation flow is formed in the tank. The preferred embodiments are the configuration of claim (3) in which a rotary blade that assists the above is provided, and the configuration of claim (4) in which the settling foreign matter outlet is provided at the bottom of the tank.

(Operation) In the vertical cylindrical tank, the amount of pipe slurry continuously introduced from the introduction pipe and the amount of liquid corresponding to the amount of diluting water are discharged from the peripheral and central overflow ports. Since at least one of the diluting water is introduced in a direction substantially tangential to the cylindrical shape, a constant liquid flow is generated in the tank along the circumferential direction due to the introduced liquid pressure. Due to this circulating flow, the liquid in the tank becomes a vortex with its center as the center, and the suspended matter on the liquid surface behaves so as to gather at the center of the vortex by the principle of vortex. Therefore, the lightweight foreign matter mixed in the pulp slurry separates from the pulp in the tank, floats, reaches the liquid surface, and moves to the center of the tank. The liquid is discharged from the overflow port to the outside of the tank, and the liquid containing almost no lightweight foreign matter is discharged from the overflow port at the peripheral portion, so that this can be collected as a carefully selected slurry. Normally, bubbles are generated in the liquid, but since the bubbles enclose the lightweight foreign matter toward the center of the vortex, the removal efficiency is further enhanced.

Here, the dilution water has a slurry concentration of about 0.4 in the tank.
% To lessen the entanglement between pulp fibers and increase the fiber spacing to facilitate the release of foreign substances.

Further, the dilution water and the pulp slurry may be introduced into the tank through separate introduction pipes, or both may be mixed in advance and introduced into the tank through a single introduction pipe. When using separate introduction pipes, only one of the introduction pipes may be connected in a substantially tangential direction with respect to the cylindrical shape of the tank in order to form a circulation flow. If so, there is an advantage that the strength of the circulating flow, that is, the vortex can be easily adjusted by the change in the liquid amount. Needless to say, it is most desirable that both the introduction pipes are connected in the substantially tangential direction.

By providing a baffle plate in the vicinity of the overflow port at the peripheral edge to deflect the liquid flow from the overflow port, it is possible to more completely prevent the lightweight foreign matter from flowing out from the overflow port. In this case, a lightweight foreign matter removal efficiency of 95% or more can be achieved.

Further, by providing a rotary vane inside the tank and rotationally driving the rotary vane by a motor or the like, it is possible to assist the formation of the above-mentioned circulating flow, and it becomes easy to stabilize the flow and adjust the strength.

On the other hand, by providing an outlet for the settling foreign matter at the bottom of the tank, it is possible to remove heavy foreign matter such as soil and sand mixed in the pulp together with the lightweight foreign matter. When using the equipment of the present invention,
The installation place is not particularly limited, but it is most effective to treat the rectified raw material at the final stage of the screen process. In this case, even if a piece of wood-like undigested material coexists in the pulp, there is no problem in the light weight foreign matter separation efficiency.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the first embodiment shown in FIGS. 1 and 2, reference numeral 1 denotes a vertical cylindrical tank having a bottom portion constricted in an inverted conical shape, and a side plate portion 1a thereof has a dilution water introducing pipe 2 and a pulp slurry introducing pipe 3 Are connected to each other in a substantially tangential direction to the cylindrical shape, and an overflow port 5 that communicates with an upper end opening of the carefully selected slurry outlet pipe 4 and constitutes a carefully selected pulp take-out portion is laterally bulged out at one place in the upper peripheral edge. It is provided in a shape. Then, a single lightweight foreign matter outlet pipe 6 is provided along the center axis of the tank 1, and the funnel-shaped opening at the upper end thereof is located in the upper portion of the tank 1 to serve as a lightweight foreign matter extraction portion. It constitutes the overflow port 7 at the center. This outlet pipe 6
The upper part 6a of the is connected to the lower part 6b of the separate body through the connecting tube 8 with the fixing screw.
Is connected so that the vertical position can be adjusted. The bottom of the tank 1 is connected to a settling foreign matter outlet pipe 10 via a blow valve 9.

The tank 1 is hermetically sealed by mounting a lid plate 1b on the upper portion thereof as shown in FIG. Reference numeral 1c is an opening / closing port for inspection provided on the cover plate 1b.

In the separation device having the above structure, the tank 1 is connected by the outlet pipes 2 and 3.
The dilution water W and the pulp slurry S are continuously introduced into the inside at a constant flow rate, and the liquid corresponding to the introduced amount overflows from the overflow ports 5 and 7 and is continuously discharged from the outlet pipes 4 and 6. However, since the introduction directions of the two introduction pipes 2 and 3 are substantially tangential, a counterclockwise circulating flow shown in the drawing is generated in the tank 1. Therefore, the minute lightweight foreign matter A such as plastic or rubber in the pulp slurry S is separated from the pulp fibers by the dilution of the slurry S and floats, and is gathered toward the center side of the tank 1 by the centripetal force of the vortex and overflow port. 7 and then discharged from the outlet pipe 6. As a result, the liquid containing almost no lightweight foreign matter A flows out from the overflow port 5 in the peripheral portion,
The selected slurry is discharged from the outlet pipe 4.

Then, as shown in FIG. 3, the selected slurry recovered from the outlet pipe 4 is dehydrated by the dehydrator 11 and provided to the next step. The liquid containing the lightweight foreign matter discharged from the outlet pipe 6 is separated into the foreign matter A and the liquid by the inclined net 12. Since the liquid after separation of the foreign matter A contains pulp, it is usually mixed with water separated by the dehydrator 11 and mixed again in the pulp slurry S for the purpose of improving the yield for reprocessing. Be served.

On the other hand, heavy foreign matter such as soil and sand contained in the pulp slurry S settles in the tank 1 and is buried in the bottom, so that the blow valve 9 is opened and withdrawn from the outlet pipe 10 every predetermined time.

FIG. 4 shows a foreign matter separating device according to a second embodiment of the present invention. This device is constructed in the same manner as the separating device of the first embodiment except that it has a baffle plate 13 extending inward from the side plate part of the tank 1 in the vicinity of the overflow port 5 in the peripheral part. There is. The baffle plate 13 is arranged so as to project slightly above the liquid surface above the liquid surface and to deflect the flow direction of the circulating flow from the overflow port 5. Therefore, in this separation device, the lightweight foreign matter that has floated to the liquid surface is more reliably prevented from flowing out to the overflow port 5, and the lightweight foreign matter removal efficiency is further improved compared to the first embodiment.

FIG. 5 shows a separating device according to a third embodiment of the present invention. This device is the device of the second embodiment additionally provided with paddle type rotary blades 14. By rotating the rotary blades 14 in the forward direction with the circular flow by a motor or the like, the circular flow is formed. The circulation flow can be stabilized and the strength of the circulation flow can be adjusted by the change in the rotation speed.

In the foreign matter separating apparatus of the present invention, the detailed configuration such as the connection position of the outlet pipes 2 and 3 with respect to the tank 1 and the structure of the overflow port 5 at the peripheral portion can be variously modified in addition to the examples.

(Effects peculiar to the invention) The foreign matter separating device for pulp according to the present invention can significantly improve the efficiency of removing light foreign matter such as plastics and rubber, so that the quality of the product paper can be greatly improved and the oxygen desorption It is possible to fully cope with the closed system of the screen process accompanying the adoption of the lignin method, and since the vertical tank is used, the space efficiency in the foreign substance separation process can be improved as compared with the case where a conventional long horizontal separation tank is used.

Further, according to the separation device of the second aspect of the present invention, the removal efficiency can be further enhanced.

Similarly, according to the separation device of claim (3), there is an advantage that a stable circulating flow can be reliably formed and that the circulating flow can be easily adjusted to a strength that maximizes the removal efficiency.

According to the separation device of claim (3), there is an advantage that heavy foreign matter such as soil and sand can be easily separated and removed together with the light weight foreign matter.

[Brief description of drawings]

FIG. 1 shows an embodiment of a device for separating foreign matter in pulp according to the present invention. FIG. 1 is a perspective view of a peripheral device of the first embodiment, FIG. FIG. 4 is a schematic diagram showing the arrangement configuration of a processing system using the same device, FIG.
FIG. 5 is a perspective view of the same device of the third embodiment, and FIG. 5 is a perspective view of the same device of the third embodiment. 1 ... Tank, 2 ... Diluting water introducing pipe, 3 ... Pulp slurry introducing pipe, 5 ... Peripheral overflow port, 7 ... Central overflow port,
10 ... Sedimentation foreign matter outlet pipe (sedimentation foreign matter extraction part), 13 ... Baffle plate,
14 ... Paddle type rotary blade, A ... Light weight foreign matter, S ... Pulp slurry, W ... Diluting water.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Katsuyoshi Yamashita, 1 Yoshida, Toyomae-cho, Anan-shi, Tokushima Kanzaki Paper Co., Ltd. Tomioka Mill (72) Toshio Sakaguchi, 1 Yoshida, Toyoma-cho, Anan-shi, Tokushima Kanzaki Paper Manufacturing Co., Ltd., Tomioka Mill (56) Reference JP-A-60-90054 (JP, A) JP-A-54-142305 (JP, A)

Claims (4)

[Scope of utility model registration request] 1. A vertical cylindrical tank is provided with an overflow port serving as a selected pulp take-out portion at a peripheral portion of the upper portion thereof, and an overflow port serving as a lightweight foreign matter take-out portion is provided at a central portion of the tank, Further, an apparatus for separating foreign matter in pulp, wherein an introduction pipe of pulp slurry and / or dilution water is connected to a side plate portion of the tank so that at least one liquid introduction direction is substantially tangential to the cylindrical shape. 2. The apparatus for separating foreign matter from pulp according to claim 1, wherein a baffle for diverting the liquid flow from the overflow port is provided in the vicinity of the overflow port at the peripheral portion. 3. An apparatus for separating foreign matter from pulp according to claim 1, wherein the tank is provided with a rotary blade for assisting the formation of a circulating flow. 4. An apparatus for separating foreign matter from pulp according to any one of claims (1) to (3), wherein an outlet for the sedimented foreign matter is provided at the bottom of the tank.