JP2766734B2 - White water recovery system with fiber classifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white water recovery system with a fiber classifier used in the paper industry.

[0002]

2. Description of the Related Art Water containing fine fibers and fillers (white clay) generated in a wire squeezing section of a paper making machine is called white water, but surplus white water that is no longer required in the paper making section is sent to a raw material preparation section. It is sent and the fine fiber content of the white water is collected by the white water recovery device,
It is sent out to a seed box and a papermaking raw material box to make paper again.

[0003] On the other hand, the clarified filtrate recovered in the process of recovering the fine fibers in the excess white water by the white water recovery device is used for shower water for papermaking machines, dilution water in the system, and the like. FIG. 5 shows a representative example of a white water recovery system including a recovery device.

In FIG. 5, surplus white water generated in a papermaking machine section is supplied to a white water mixing tank 2 by an excess white water line 1. 7 is a white water recovery device, which is the most important device in the white water recovery system. FIG. 5 shows the most commonly used disk-type white water recovery device. A net is provided on the surface of the disk, a fiber layer is formed on the surface of the net, and filtration is performed through the fiber layer. This is a device that collects excess white water. Also, in order to filter through the fiber layer formed on the surface of the net, a part of the raw material having a long fiber length and high drainage of the raw material line is taken out as a fiber layer forming medium and mixed with excess white water. It needs to be supplied to the white water recovery device. Also, one part of the crude material is taken out of the distribution box 4 and
The treated white water supplied to the white water mixing tank 2 through the fiber layer forming medium transport pipe 5 and mixed with the surplus white water is supplied to the white water recovery device 7 by the white water transport pipe 6 to be treated.

[0005] In the white water collecting device 7, the fine fiber component in the excess white water is collected in a mat shape together with the fiber layer forming medium conveyed by the fiber layer forming medium conveying pipe 5, and is subsequently disintegrated by the disintegration conveying machine 8. It is transported and stored in the recovery tank 9. After the fiber content is agitated in the recovery tank 9 to achieve a uniform concentration, the fiber can be sent to the mixing tank 11 through the recovery fiber transport pipe 10 in order to return to the main line in which the crude material flows.

[0006] In the mixing tank 11, the fiber layer forming medium transport pipe 5
The remaining crude material after extracting a part of the crude material with the recovered fiber fed by the recovered fiber transport pipe 10 is mixed, and after mixing necessary chemicals and the like, the papermaking supply layer 1 is mixed.
2. In the order of the seed box 13, the paper is fed out to the papermaking machine wire section through the papermaking supply line 14, and papermaking is performed.

[0007] The filtrate recovered by the white water recovery device 7 is:
It can be divided into clear water and semi-turbid water,
The ends of the semi-turbid water pipe 15 and the clear water pipe 16 are opened below the seal pit liquid level so that the semi-turbid water can be guided to the seal pit 17 by the semi-turbid water pipe 15 and the clarified water can be sealed by the clarified water pipe 16. ing. The recovered semi-turbid water is reused by a pump device 18 and the clarified water is reused as shower water or dilution water of a papermaking machine in various parts of the system by a pump device 19.

Next, FIG. 6 shows an external appearance of an example of a disc-type white water recovery apparatus which is a main apparatus of the white water recovery system. FIG. 9 is a cross-sectional view of a shaft portion, and FIG. 10 is a side view of the shaft portion. Rings 24 are arranged at equal intervals in the longitudinal direction of the shaft on the surface of the ring 24, and an opening 25 is arranged in the ring 24 in a region where the ring 24 and the flow path 22 intersect. FIG. 11 shows a disk portion, in which a sector 26 covered with a net 27 corresponding to the opening 25 is disposed in the groove of the ring 24, and a shaft 28 is fixed by a stopper 28 so that the sector becomes disk-shaped. 20.

FIG. 12 is a side view of the white water collecting apparatus, in which a shaft with a sector sector 26 is provided at the center of the container 23 so as to be rotatable. A treated white water inlet 32 is provided at one end of the container 23, and the surface of the treated white water supplied to the container 23 is maintained at the center of the container, while the surface of the sector-shaped sector network 27 submerged below the liquid surface is provided. Forms a fiber layer. The filtrate having passed through the fiber layer is divided into the sector 26 shown in FIG.
7 through the opening 25 shown in FIG. 9 and the sliding valve device 29 shown in FIGS. It can be led out.

The filtrate in the early stage of forming the fiber layer passes through the semi-turbid water pipe 15 from the semi-turbid water port 30 of the sliding valve device 29, while the filtrate in the later stage passes from the clarified water port 31 through the clarified water pipe 16 to the seal pit 17, respectively. And can be collected separately.
After the fiber layer formed on the mesh 27 provided on the surface of the sector sector 26 is lifted above the liquid surface by the rotation of the shaft 20, the fiber layer is removed by the stripping shower device 33 shown in FIG. 27, is stripped off, falls in the area of the collection gutter 34, and is sent to the collection tank 9 by the disaggregation transporter 8.

[0011]

A fibrous layer is formed on the surface of the reticulated body, and in the course of the white water to be treated passing through the fibrous layer, the fibers and fillers (white clay) in the white water to be treated are trapped in the fibrous layer. In the conventional white water collecting apparatus 7 in which the water in the white water to be treated is clarified and filtered through the fiber layer while being collected, the raw material that is the fiber layer forming medium for forming the fiber layer and the surplus to be treated Since the white water is mixed with the white water and sent to the white water recovery device 7 to form a fiber layer, the filtration performance is determined by the properties of the raw material, that is, the papermaking raw material, and the properties of the liquid processing surplus white water.

In the conventional white water treatment system, when the composition of the raw material is viewed as a fiber length distribution, it is generated from a papermaking machine such as newsprint having a high proportion of short fibers, poor drainage, and a large amount of mechanical pulp. In the case of recovering excess white water, especially when the ratio of the raw material of the fiber layer forming medium to the solid content in the excess white water to be treated is continuously increased, the filtration efficiency of the raw material is poor because the raw material has poor drainage. Rate is low, there is a problem that the amount of white water to be treated increases due to an increase in the amount of water brought in by the crude material, and an increase in the thickness of the formed fiber layer causes a decrease in filtration performance, and the filtration area of the white water recovery device is large. In addition, there is a disadvantage that the vehicle must be operated at a low speed.

The present invention has been proposed to solve the above-mentioned conventional problems.

[0014]

SUMMARY OF THE INVENTION Accordingly, the present invention relates to an apparatus for recovering surplus white water generated in a papermaking machine section, wherein a solid content recovered by the white water recovery apparatus is separated by a fiber classifier, and a long fiber separation is performed. The material is returned to the white water recovery device as a fiber layer forming medium and is circulated and used, and this is used as a means for solving the problem.

[0015]

The collected fiber content recovered by the white water recovery device can be separated into a long fiber aggregate and a short fiber aggregate by treating with a fiber classifier. In addition, the long fiber fraction aggregate separated by the fiber classifier is circulated to the white water mixing tank, mixed with the excess white water to be treated, and then processed by the white water recovery device. Can be maximized, and the filtration rate performance of the white water recovery device can be improved by improving the drainage.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an embodiment of the present invention; FIG. First, FIG. 1 shows a first embodiment of the present invention, in which a pressure-type fiber classifying device 100 is disposed in the middle of a collected fiber transport pipe 10, and the collected fiber is divided into a long fiber aggregate and a short fiber aggregate. A long fiber aggregate transfer pipe 101 is provided so as to be separated and communicate with the white water mixing tank 2 from the long fiber aggregate outlet.

On the other hand, the separated short fiber aggregate is provided with a short fiber aggregate transport pipe 10A so that the mixing tank 11 can be connected to the short fiber aggregate outlet of the fiber classifier 100. Further, a branch portion is provided in the middle of the long fiber aggregate transport pipe 101, and a branch recovery pipe 102 for the long fiber aggregate is provided so that the mixing tank 11 can be connected from the branch portion.

The long fiber fraction separated by the fiber classifying apparatus 100 is sent to the white water mixing tank 2 by the long fiber aggregate transport pipe 101, and the raw material transported by the tank forming medium transport pipe 5 to the surplus white water After being mixed with the surplus white water from the line 1, it is sent to the white water recovery device 7 by the white water conveying pipe 6 to be treated.
The amount of the long fiber from the fiber tank forming medium transport pipe 101 and the amount of the long fiber from the long fiber aggregate transport pipe 101 are controlled by the properties of the surplus white water. By optimizing the content and improving the drainage, the filtration speed performance of the white water recovery device 7, that is, the filtration area of the white water recovery device 7 can be minimized.

A part of the long fiber aggregate is sent out to the mixing tank 11 by a branch recovery pipe 102 branched from the long fiber aggregate transport pipe 101, and is transported by the fiber layer forming medium transport pipe 5. It is necessary to return the physical quantity of the long fiber aggregate corresponding to the physical quantity of the raw material to the mixing tank 11 so that the physical quantity balance around the white water recovery device 7 can be maintained.

FIG. 2 shows an embodiment of the fiber classifying apparatus 100. In the container 103, a short fiber assembly outlet 105 tangentially disposed in the upper cylindrical portion of the container, and a short fiber outlet 105 disposed below the container. A fiber aggregate outlet 106 and a dilution water inlet 107 are provided. In addition, a lid 108 is provided at the top of the container, and an air outlet 109 is provided at the center.

On the other hand, the container 103 is provided with a classification tube 110 having a large number of pores for classifying the fiber, and is fixed to the container 103 by pressing the classification tube with a fixed ring 111. A separating wall is formed between the fiber component and the short fiber component aggregate. Further, the stirring device provided at the center of the container 103 is configured as follows. A rotating body 112 having a plurality of hemispherical projections 112A on the surface of the rotating body is fixed to an upper end portion of a main shaft 113 for transmitting rotation.
It is supported by the lower two sets of bearings and is fixed to the bearing support 114. The bearing support 114 is fixed to the container 103, and forms a part of the container 103 to maintain the pressure in the container. Further, the rotating drum 112 is provided with the power transmission device 1.
15 to prevent sedimentation of the fiber in the container, clean the surface of the classification cylinder 110, and prevent clogging of the classification cylinder.

The fiber content supplied from the inlet 104 is
In the process of passing through the area between the classification cylinder 110 and the rotating drum 112, the short fiber component passes through the pores of the classification cylinder 110, flows to the short fiber segment aggregate outlet 105, and passes through the pores of the classification cylinder 110. The long fiber that has not been obtained proceeds downward and is discharged from the long fiber liquor outlet 106. The opening of the classification cylinder 110 may be either a round hole or a slit, and there is no limitation. Also, there is no practical limit to the operating concentration of the fiber classifier 100,
Preferably, about 3% or more is an economical practical condition.

FIG. 3 shows a second embodiment of the present invention. In FIG. 3, a part of the crude material taken out from the distribution box 4 is sent to the collection tank 9 through the fiber layer forming medium conveying pipe 5 and mixed with the collected fiber from the white water collecting device 7.
Is supplied to the white water mixing tank 2 by the long fiber liquor heavy goods transport pipe 101, mixed with the surplus white water 1 to be treated, and supplied to the white water recovery device 7.
The embodiment of FIG. 3 is particularly effective when the composition of the crude material has a low content of long fibers. Others are the same as the embodiment of FIG.

FIG. 4 shows a third embodiment of the present invention, which is a modification of a part of FIG. In FIG. 4, the long fiber fraction separated by the fiber classification device 100 is stored in a long fiber fraction storage tank 15.
0, once stored, and then transported to the long-fiber segment aggregate transport pipe 101.
Is supplied to the white water mixing tank 2. Long fiber storage tank 15
The long fiber portion from 0 to 1 portion can be sent out to the mixing tank 11 by the branch collection pipe 102, and the amount of the collected long fiber corresponding to the amount in the fiber layer forming medium transport pipe 5 is transferred to the crude material line. You can go back. As described above, the embodiment of FIG. 4 is provided with the operational flexibility by disposing the long fiber storage tank 150.

[0025]

As described in detail above, according to the present invention, the recovered fiber fraction recovered by the white water recovery apparatus is separated into the long fiber fraction and the short fiber fraction by the fiber classification apparatus. The long fiber aggregate of the recovered fibers is sent to a white water recovery device and can be reused as a fiber layer forming medium. Further, since the composition of the crude material is determined depending on the type of papermaking paper, the proportion of the fiber length distribution is substantially determined. For this reason, even if the crude material has poor drainage even if the ratio of the crude material as the fiber layer forming medium is continuously increased with respect to the solid content in the excess white water to be treated, the rate of improvement of the filtration performance is particularly low, and There was a drawback that the amount of white water to be treated was increased due to an increase in the amount of water brought in, and the filtration resistance was increased due to an increase in the thickness of the formed fiber layer. Thereby, the composition ratio of the long fibers in the white water to be treated can be maximized, so that the drainage can be improved.

Accordingly, the filtration speed performance of the white water recovery device is improved, so that the filtration area of the white water recovery device is minimized and the rotation speed can be maximized. Further, the short fiber fraction aggregate separated by the fiber classification device and the amount of long fiber fractionated alcohol separated by the fiber classification device corresponding to the amount of the crude material as the fiber layer forming medium of the white water recovery device are sent to the mixing tank. Therefore, there is no circulating accumulation of fine fibers around the white water recovery device, and the operation of the white water recovery device can be continued while maintaining the physical quantity balance.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a white water recovery system according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an embodiment of a fiber classification device according to the present invention.

FIG. 3 is a flow sheet of a white water recovery system according to a second embodiment of the present invention.

FIG. 4 is a flow sheet of a white water recovery system according to a third embodiment of the present invention.

FIG. 5 is a flow sheet of a conventional white water recovery system.

FIG. 6 is a partial cutaway side view showing an example of a conventional white water recovery apparatus.

FIG. 7 is a detailed view of a main part in FIG. 6;

FIG. 8 is a perspective view of a main part in FIG. 7;

FIG. 9 is a sectional view of a main part in FIG. 7;

FIG. 10 is a view as viewed from arrows A to A in FIG. 9;

FIG. 11 is a detailed perspective view of a disk portion in FIG. 6;

FIG. 12 is a view taken in the direction of arrow B in FIG. 6;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 surplus white water line 2 white water mixing tank 5 fiber layer forming medium transport pipe 7 white water recovery device 10 recovery fiber transport pipe 10A short fiber aggregate transport pipe 100 fiber classifier 101 long fiber aggregate transport pipe 102 branch recovery pipe

Claims (1)

(57) [Claims] In a recovery apparatus for surplus white water generated in a papermaking machine section, solids recovered by the white water recovery apparatus are separated by a fiber classification apparatus, and a long fiber fraction aggregate is recovered as white water recovery medium as a fiber layer forming medium. A white water recovery system with a fiber classification device, which is returned to the device and recycled.