JPH0593386A - Screen device - Google Patents

Abstract

PURPOSE:To obtain the subject apparatus, capable of applying a pressure to a paper stock, passing the paper stock through a screen, feeding a prescribed amount of water, readily removing unnecessary parts collecting on the inlet side of the screen and useful for recycling laminated paper, etc. CONSTITUTION:The objective screen device 38 is equipped with a screen having small holes, e.g. 15/1000 inch diameter formed therein and capable of filtering a paper stock obtained by disaggregating mutilayered paper containing metallic foils such as Al. In the above-mentioned screen device, an impeller 40 is rotated to pressurize the paper stock, which is passed through the screen 42. At this time, water is added from the outside to produce convection. Thereby, impurities such as the Al incapable of passing through the holes are efficiently removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen device for use in a used paper recycling system, which enables pure pulp to be taken out from a laminated paper containing a layer of metal foil such as aluminum and reused as paper. It is a thing.

[0002]

2. Description of the Related Art In recent years, environmental problems on a global scale such as global warming have been highlighted, and it has become an international concern to investigate the cause and take countermeasures. For example, if the amount of paper used continues to increase as it is, the amount of dust will also increase, and by incinerating this, a large amount of carbon dioxide will be emitted. This also accelerates the destruction of the natural environment.

On the other hand, in recent years, the amount of paper used has been increasing due to the popularization of office automation equipment and the development of various paper products, and it is difficult to suppress the amount of pulp used. Therefore, the recycling of used paper is drawing attention, and efforts are being made to recycle used paper into usable paper. Recycled waste paper has been used for many years. Paper containers, such as milk cartons, use good quality pulp, and it is very valuable to recycle paper products for various uses from them.

By the way, some paper containers are made of laminated paper having a metal layer such as aluminum foil.
A typical one of such laminated paper is a paper in which five layers of polyethylene and aluminum foil are stacked in addition to the paper. By providing a layer of aluminum foil inside the container in this way, the contents can be sealed in the same manner as canned goods, so that oxygen and light are completely shielded. Therefore, when the product is sterilized and filled in such a container, it can be stored for a long period of time. Taking advantage of these advantages, this kind of container is widely used as a container for juice, long-life milk, liquor, coffee and the like.

[0005]

However, in the case of the paper container having the aluminum foil layer as described above, the pulp has not been recycled so far even though it contains many pulp raw materials. The reason is that when pulp is regenerated in the same way as a container that does not contain aluminum foil, the aluminum foil crushed in the pulp regeneration process mixes with the pulp, and the final paper has a large amount of aluminum foil. This is because it will not be put to practical use.

Therefore, the treatment of such a paper container becomes a problem. In the case of such a container, even if incinerated, only the part other than aluminum burns, and if the aluminum is forcibly burned to a high temperature, the incinerator itself may be damaged. Further, the method of incineration is not preferable from the viewpoint of releasing carbon dioxide and reusing resources. Further, a method of burying in the ground was also adopted, but aluminum is not easily decomposed in the ground, which leads to new environmental damage. For this reason, in Europe and America, there is a movement to ban the use of paper containers containing aluminum.

Therefore, if possible, it is desirable to recycle such a container, but as described above, in the conventional used paper recycling system, in the case of a paper container having a layer of aluminum foil, pulp can be recycled. could not. One of the causes is a screen device. That is, in the screen device used in the conventional used paper recycling system, the metal foil such as aluminum having a predetermined size or more is removed from the stock solution obtained by disintegrating the laminated paper containing the metal foil such as aluminum. In that case, there is a problem that clogging occurs and the fine aluminum cannot pass through the screen and the metal foil cannot be removed.

The present invention has been made based on the above circumstances, and from a stock solution obtained by disintegrating a laminated paper containing a metal foil such as aluminum, a metal foil such as aluminum having a predetermined size or more, etc. It is an object of the present invention to provide a screen device capable of easily removing the unnecessary substances.

[0009]

In order to achieve the above object, the first invention is a screen device for filtering disintegrated stock liquid, comprising a screen having fine holes of a predetermined size formed therein. , Pressurizing means for applying pressure to the stock solution to pass through the screen, water supply means for supplying a predetermined amount of water to the inlet side of the screen, and unnecessary portions remaining at the inlet side of the screen are removed And a means for removing unnecessary substances.

A second invention for achieving the above object is the same as the first invention, wherein the pressurizing means applies a slight vibration to the screen plate by rotating a rotary blade to apply the stock solution. It is characterized by being passed through by pressure.

A third aspect of the invention for achieving the above object is, in the first or second aspect of the invention, unnecessary substances accumulated in the screen are diluted with a large amount of water, decomposed into pulp, and discharged by overflow. After passing through a tail screen having holes larger than the fine holes of the screen, it is returned to the pretreatment step.

[0012]

According to the first aspect of the present invention, the stock solution obtained after the disintegration treatment of laminated paper containing a metal foil in a pulper is diluted with a large amount of water at the entrance side of the screen to reduce the concentration. Performing a filtering operation by rapidly and continuously overflowing undesired material of a size that does not pass through the screen by pressurizing it with a pressurizing means and at the same time, for example, a metal foil such as aluminum. Therefore, unnecessary substances such as metal foil can be easily removed without causing clogging.

According to a second aspect of the present invention, the pressing means presses the stock solution by rotating the rotary blades, so that the stock solution having a predetermined size or less is used. Can be passed through the screen, and at the same time, unnecessary substances accumulated at the entrance side of the screen can be pushed to the peripheral portion of the screen.

According to the third aspect of the present invention, since the raw material concentration is diluted with a large amount of water and unnecessary substances are continuously overflow discharged together with water according to the above-mentioned constitution, the unnecessary substances can be efficiently removed, and the pulp can be efficiently removed. Some of the pulp is not finely disintegrated and is taken out to the outside together with unnecessary substances. It can be reused without waste.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a flow of a process of regenerating pulp from a used paper container or processing waste by a pulp regenerating system using a screen device which is an embodiment of the present invention, and FIG. A cross-sectional view of laminated paper used as a raw material, FIG. 3 is a schematic cross-sectional view of a pulper 20 into which a used paper container as a raw material is initially charged, and FIG. 4 is an enlarged view of the vicinity of the impeller and screen shown in FIG. 5 is a sectional view of the screen device, and FIG. 6 is a simplified sectional view of the paper making device. In this system, as a raw material, a paper container made of laminated paper of three kinds and five layers including an aluminum foil layer as a cross section is used. As shown in the figure, this laminated paper is
A polyethylene layer of about 0 microns, an aluminum foil layer of about 9 microns 12, a polyethylene layer of about 15 microns 14, a base paper (pulp) layer 16 of about 310 to 340 g / m ² , and a polyethylene layer of about 15 microns. It consists of 18 layers.

To the pulper 20 shown in FIG. 3, 5 kg of caustic soda and 20 kg of sodium hypochlorite are added to 1 ton of raw material. Here, caustic soda is for disintegrating pulp, and sodium hypochlorite is for bleaching pulp. Inside the tank 22 of the pulper 20, as shown in FIG. 3, an impeller (rotary blade) 24 for agitating the stock solution, and a stainless steel screen 26 having a large number of holes under the impeller 24 are provided. Is provided. As shown enlarged in FIG. 4, the impeller 24
The distance between the back side of the and the screen 26 is significantly smaller than that of the conventional pulper, and is about 2 mm or less.
By narrowing the gap between the impeller and the screen in this way, a turbulent flow is generated in the space between them, and the pulp that has settled on the screen can be wound up on top of the impeller without passing through the screen. It can be promoted and the screen can be prevented from clogging.

In the pulper 20, the raw materials and the above-mentioned chemicals are charged, the temperature is kept at about 40 ° C., and the impeller 24 is set at about 1 ° C.
The pulp is disintegrated by rotating with a 50 horsepower motor and stirring the raw materials and chemicals for about 1 hour. The pulp thus disintegrated passes through a screen with a number of holes 30 1-5 mm in diameter under the impeller. On the other hand, most of the aluminum and polyethylene are taken out as unnecessary substances from the gate valve 28 provided on the side surface of the tank.

By performing the treatment with the pulper 20 in this manner, about 99.1% of aluminum can be removed. However, the aluminum finely crushed by the impeller 24, together with the pulp, has holes 30 in the screen.
Pass through. Therefore, too much aluminum is still mixed in to recycle the pulp into usable paper.

The pulp that has passed through the screen 26 of the pulper 20 enters a beating refiner 34 through a porcher 32 as shown in FIG. This beaten refiner has a structure similar to that of a stone mill, and further disintegrates pulp disintegrated with a pulper.

The pulp discharged from the beating refiner 34 passes through a porcher 36 and then enters a first screen device 38 for removing dust. As shown in FIG. 5, the screen device 38 rotates an impeller (rotary blade) 40 to pressurize the pulp raw material supplied from the left side to have a diameter of 15/1000.
A screen (trade name: FN screen) 42 having an inch hole is passed.

At this time, a great feature is that a large amount of water is supplied from the side of the impeller 40 by a water supply device (not shown). This water dilutes the stock solution to facilitate passage through the screen 42. Also, this added water convects at high speed along the surface of the screen 42, thereby washing away large aluminum debris that cannot pass through the screen 42 from the surface of the screen.
The disintegrated pulp easily passes through the screen. The washed-out waste material is continuously withdrawn from the side of the screen by overflow, but since this also contains recyclable pulp, the first tail screen is used for the purpose of taking out this recyclable pulp. Sent to device 44.

In the screen device used in the conventional laminated paper recycling system not containing a metal foil, the stock solution that has passed through the screen is immediately returned to the inlet side of the impeller 40 again, and the impeller again pressurizes the screen liquid. I was passing it. However, in the case of such a configuration in which the stock solution is immediately fed back, the pressure applied to the solution by the impeller has to be increased, and there is a problem that the amount of unnecessary strips passing through the screen increases. Therefore, in the present embodiment, a large amount of water is supplied to the screen device 38 and the screen is passed only once, and only the unnecessary substances that are continuously overflow-discharged are passed through the tail screen device described later and are upstream of the screen. It is configured to return to the porcher 36. As a result of this, it was revealed that the efficiency of removing unnecessary substances is increased.

When the material removed from the screen device 38 passes through the tail screen 44, only the pulp component is extracted and returned to the porter 36, and other unnecessary substances are discarded. This allows more pulp to be recovered. The diameter of many holes provided in the tail screen 44 is 20/1000 inches.

The stock solution that has passed through the screen device 38 is sent to the retention porter 48 via the washing machine 46, where the stock solution is retained for at least about 2 hours. This retention porter has a volume of 50 cubic meters, a propeller is provided inside the retention porter, and the propeller is rotated during the retention to stir the stock solution.

The stock solution that has passed through the staying porch 48 is sent to the second screen device 54 through the porch washer 50 and the machine chest 52. This screen device 54
The size of a large number of holes provided in the screen is smaller than that of the screen device 38 in the preceding stage of the retention porch 48, and is 10/1000 inch, but the other configurations are the same as those of the screen device 38. Therefore, the important point here is that a large amount of water can be added to cause convection to efficiently remove unnecessary substances attached to the front side of the screen. The unnecessary matter removed in the screen device 54 is the second tail screen device 5
No. 6, and the pulp component is sent to the porter washer as in the case of the tail screen device 44 to recover more pulp.

By thus performing the overflow discharge by the two screen devices 38 and 54, it is possible to remove a larger amount of unnecessary substances.

The stock solution that has passed through the screen device 54 is sent to the paper making device 58. FIG. 6 is a simplified cross-sectional view of the paper making device (product name bat) 58. The stock material liquid sent from the screen device 54 is supplied from the right side of the drawing. At this time, a large amount of water is passed to dilute the pulp concentration. A vacuum suction unit 62 is provided in the center of the net 60, and the vacuum suction sucks the stock liquid 66 around the net 60. At this time, by simultaneously rotating the net 60 in the direction of the arrow, only the pulp fibers are adsorbed along the circumference of the net. A large amount of water containing the remaining fine waste and pulp is vigorously overflowed to be discharged so that the waste does not adhere to the paper. The pulp thus adsorbed is couch roll 64 on top of the net 60.
It is rolled up to obtain a sheet of paper.

As described above, aluminum is removed according to each situation through several steps, and finally, pulp containing practically no aluminum is put into practical use, but the screen is regenerated. The overflow device of the devices 38 and 54, and the overflow device of the papermaking device 58 can make it actually reusable.

[0029]

As described above, according to the first aspect of the present invention, for example, from a stock solution obtained after disintegrating a laminated paper containing a metal foil in a pulper, unnecessary materials such as a metal foil such as aluminum can be easily obtained. Since it is possible to remove, it is possible to significantly reduce the amount of metal contained in the paper obtained by making pulp in the papermaking step which is a post-process, from a laminated paper containing a layer of a metal foil such as aluminum. It is possible to recycle high-quality paper with almost no impurities.

According to the second aspect of the invention, in addition to the above effects, by rotating the rotary blades to give a slight vibration to the screen plate to pressurize the stock solution, a predetermined amount of the stock solution can be obtained. For the following things, you can pass through the screen, and at the same time, you can push the unwanted matter accumulated at the entrance side of the screen to the peripheral part of the screen,
It is possible to improve the efficiency of removing unnecessary substances, and to significantly reduce unnecessary substances such as metals contained in the finally obtained recycled paper.

According to the third invention, in addition to the above effects,
The raw material concentration was diluted with a large amount of water, and unnecessary substances were continuously overflow discharged together with water, which enabled efficient removal of unnecessary substances and was taken out as unnecessary substances without passing through the fine holes in the screen. It is possible to provide a screen device capable of efficiently reusing the raw material by passing the product through a tail screen having pores larger than the fine pores and returning to the pretreatment step.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of a process of regenerating pulp from a used paper container or processing waste by a pulp regenerating system using a screen device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of laminated paper used as a raw material in an example of the present invention.

FIG. 3 is a schematic sectional view of a pulper.

FIG. 4 is an enlarged cross-sectional view showing the impeller and the vicinity of the screen shown in FIG.

FIG. 5 is a cross-sectional view of a screen device.

FIG. 6 is a simplified cross-sectional view of a papermaking device.

[Explanation of symbols]

 10, 14, 18 Polyethylene layer 12 Aluminum foil 16 Base paper layer 20 Pulper 22 Tank 24 Impeller 26 Screen 28 Gate valve 32, 36 Retaining porter 34 Refining refiner 38, 54 Screen device 40 Impeller 42 Screen 46 Washing machine 48 Retaining porter 58 Paper making device 60 circle net

Claims (3)

[Claims] 1. A screen device comprising a screen in which fine holes of a predetermined size are formed and filtering disintegrated stock solution, and pressurizing the stock solution by passing pressure through the screen. A screen device comprising: a means, a water supply means for supplying a predetermined amount of water to the inlet side of the screen, and an unnecessary substance removing means for removing an unnecessary portion remaining at the inlet side of the screen. 2. The screen device according to claim 1, wherein the pressurizing means applies a slight vibration to the screen plate by rotating a rotary blade to pressurize / pass the stock solution. .. 3. An unnecessary substance accumulated in the screen is diluted with a large amount of water, decomposed into pulp, and discharged by overflowing, and passed through a tail screen having holes larger than the fine holes of the screen. The screen device according to claim 1 or 2, wherein the screen device is configured to return to a pretreatment step later.