JPH0211309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to recycle agricultural waste film made of thermoplastic synthetic resins such as polyvinyl chloride and polyethylene, the present invention provides a method for recycling agricultural waste film made of thermoplastic synthetic resins such as polyvinyl chloride and polyethylene. The present invention relates to a separation and dehydration treatment apparatus for waste film used as a recycled raw material, for separating and removing foreign substances such as foreign film pieces and floating substances, and dewatering the same.

In recent years, with the spread of greenhouse horticulture, the usage of agricultural films, mainly made of polyvinyl chloride, has been increasing, and the disposal of unnecessary films has been forced to be reconsidered from both resource conservation and pollution issues.
Recycling of waste film has been cited as one of the promising measures to effectively solve the problem.

Various processing devices have been developed for recycling, and processing is generally performed in the following manner. In other words, the waste film is crushed by a coarse crusher.
After crushing to a size of about m/m, it is placed in a rough cleaning tank and agitated with air bubbles or mechanically agitated from below the water flow to remove sand and mud. The washed waste film pieces are further crushed in a crushing process to a size of about 10 to 30 m/m and supplied to a foreign matter separation tank, where the mixed polyethylene film, etc. is separated from the polyvinyl chloride. only is fed to the next dehydration step. In the dewatering process, a vertical centrifugal dehydrator is usually used, which consists of a rotating screw inside a rotating cylinder. It is pressed against the wall and dehydrated. The dehydrated waste film pieces are scraped up by a screw and dried in the next drying step to become a final product and used as a recycled material.

However, the conventional processing apparatus described above has the following drawbacks.

(1) The separation action of the foreign matter separation process uses the difference in specific gravity in water to separate the polyethylene film mixed in the polyvinyl chloride film while causing the water to migrate. That is, by precipitating polyvinyl chloride film, which has a higher specific gravity than water,
The polyethylene film, which has a lower specific gravity, is floated and separated, but since the difference in specific gravity between the two is small, sufficient time must be taken for sedimentation and separation, and therefore the separation tank must be made larger.

(2) If the concentration of waste film fragments in the water in the separation tank is increased, the two pieces will adhere to each other, and the polyethylene film will not float and separate, but will settle together with the polyvinyl chloride, which has a high specific gravity, resulting in poor separation efficiency and a loss of recycled raw material. This results in a decrease in quality. Furthermore, if the concentration of waste film fragments in water is lowered in order to increase the separation efficiency, the separation capacity per volume of the separation tank will be significantly reduced.

(3) In the dewatering process, conventional vertical centrifugal dehydrators rotate a cylinder with water holes at high speed in a horizontal plane.
When a piece of waste film is fed from above, it is dehydrated by centrifugal force on the inner surface of the cylinder. The waste film fragments that have been dehydrated and adhered to the inner surface of the cylinder are scraped up by a screw rotating inside the cylinder, but this may clog the water holes or deposit sand and mud on the inner wall of the cylinder. The film pieces get caught between the screw and the wall, causing problems such as bending and damaging the screw blades, making it difficult to take out the waste film pieces continuously. Therefore, the present invention has been achieved as a result of intensive research to solve the problems of the prior art. Namely, the first object of the present invention is to solve the problems of the prior art. Separation of waste film for recycled raw materials, which can effectively separate and remove foreign substances such as foreign film pieces and floating substances, dehydrate it, and continuously take out waste film pieces for recycling with a low foreign substance contamination rate and water content. The purpose of the present invention is to provide a dehydration treatment device.

Therefore, in order to achieve this first object, the waste film separation and dehydration treatment apparatus for recycled raw materials of the present invention includes an ultrasonic cleaning tank for carefully cleaning waste film pieces, and an ultrasonic cleaning tank that cleans the waste film pieces. Foreign matter such as different kinds of film pieces and floating matter adhering to the waste film pieces that have been thoroughly washed are separated and floated in water due to the difference in specific gravity, and the settled waste film pieces are removed. It is comprised of a foreign matter separation tank for taking out, an adjustment tank for adjusting the concentration of the waste film pieces taken out from the foreign matter separation tank, and a horizontal centrifugal dehydrator for dewatering the waste film pieces supplied from the adjustment tank by a transfer pump. It is characterized by

In addition, in order to separate and remove foreign substances such as foreign films and floating substances from waste film pieces, the time required for sedimentation and separation is longer because the difference in specific gravity between the two is small, and in order to cope with this, the separation tank must be made larger. As already mentioned, simply increasing the size of the separation tank does not significantly improve separation efficiency, making it impossible to quickly and efficiently separate and dehydrate waste film, and avoid increasing the size of the entire device. There are no drawbacks.

Therefore, the second object of the present invention is to mechanically force the waste film pieces supplied into the foreign matter separation tank to promote separation, thereby significantly improving the separation efficiency.
By increasing the separation capacity per volume and downsizing the separation tank, it is possible to extremely effectively separate and remove foreign substances such as foreign film fragments and floating matter adhering to waste film fragments to be recycled, as well as to dehydrate them. ,
It is an object of the present invention to provide a separation and dehydration processing apparatus for waste film for recycling raw materials, which can continuously take out recycled film pieces with a low foreign matter contamination rate and a low water content, and also allows the processing apparatus to be made compact.

Therefore, in order to achieve this second purpose,
The separation and dehydration treatment apparatus for waste film for recycled raw materials of the present invention includes an ultrasonic cleaning tank for carefully cleaning waste film pieces, and a waste film piece that is purified by cleaning the waste film pieces supplied from the ultrasonic cleaning tank. a foreign matter separation tank that separates and floats foreign matter such as different types of film fragments and floating substances adhering to each other in water based on a difference in specific gravity, and removes the settled waste film fragments;
It is composed of an adjustment tank that adjusts the concentration of the waste film pieces taken out from the foreign matter separation tank, and a horizontal centrifugal dehydrator that dehydrates the waste film pieces provided from the adjustment tank by a transfer pump, and the foreign matter separation The tank includes a guide wheel that submerges the waste film pieces supplied into the foreign matter separation tank, a water injection nozzle that disperses and transfers the submerged waste film pieces to a separation area, and a waste film piece that migrates in the water. Two separation plates with adjustable inclination angle and vertical mounting position that collide to promote separation and sedimentation, a discharge gate that can be opened and closed to allow separated and floated foreign matter to flow out, and waste film pieces that have settled to the bottom of the foreign matter separation tank. It is characterized by having a scraping device for taking out.

The present invention will be explained below with reference to an illustrated embodiment.

FIG. 1 shows an apparatus for separating and dehydrating waste film for recycled raw materials according to the present invention.
Then, from the carefully cleaned waste film pieces supplied from the ultrasonic cleaning tank 1, foreign substances such as foreign film pieces and floating substances adhering to the waste film pieces are removed in water, for example, in warm water, due to the difference in specific gravity. a foreign matter separation tank 2 which separates and floats the waste film pieces to be removed and takes out the settled waste film pieces; and an adjustment tank 3 which adjusts the concentration of the waste film pieces taken out from the foreign matter separation tank 2.
and a transfer pump 4 and a transfer pipe 5 from the adjustment tank 3.
a horizontal centrifugal dehydrator 6 for dewatering the waste film pieces supplied by the above, a floating object draining conveyor 7 for receiving foreign objects floating in the foreign object separation tank 2 and draining the floating objects, and a floating object draining conveyor 7 for removing the floating objects after the water has been drained. It is roughly composed of a floating object storage tank 8 for storing.

Next, each component of the processing device will be explained in detail.

The ultrasonic cleaning tank 1 has hot water, for example, 40
Hot water of about ~50℃ is stored, and waste film pieces (for example, polyvinyl chloride film pieces) of about 10 to 30 mm in size are irradiated with ultrasonic waves to remove the waste film pieces. It is equipped with a net conveyor 1a which can carry out thorough washing and also supplies the washed waste film pieces to the polyseparation tank 2 in the next stage after draining.

Next, the foreign matter separation tank 2 is
As shown in FIGS. 3 and 3, there is a tank 9 filled with hot water and containing waste film pieces, and a tank 9 that is rotationally driven by an entrance guide wheel drive motor 10 to force the waste film pieces supplied by a draining conveyor 1a into the hot water. an inlet guide wheel 11 that allows the waste film pieces to sink, a water spray nozzle 12 that sprays water toward the inlet guide wheel 11 to promote settling of the waste film pieces, and generates a water flow in the tank 9 to cause the waste film pieces to sink in the warm water. A water injection nozzle 13 is provided at intervals in the separation area P in the tank 9, and the waste film pieces migrated by the water injection nozzle 13 are collided with each other to separate different types of waste film from the waste film pieces. First and second separation plates 14 and 15 that promote the separation of foreign matter such as film and floating matter, and promote the settling of only waste film pieces to the bottom of the tank due to the difference in specific gravity, and a floating matter discharge guide wheel drive electric motor 16
a floating object discharge guide wheel 17 which is rotationally driven to collect separated and floated foreign objects, and a discharge gate 18 whose floating object outlet 18a can be opened and closed freely by sliding and which guides the collected floating objects (foreign objects) to the draining conveyor. A scraping device 19 takes out the waste film pieces settled at the bottom of the tank 9 and guides them to the next stage adjustment tank 3.
It is composed of.

The first and second separation plates 14 and 15 are both adjustable in angle of inclination and vertical mounting position, and the first separation plate 14 is made of a perforated plate with a diameter of about 5 m/m, for example, and the upper end of the plate is Although it protrudes above the water surface, cutouts are provided at both ends of the separation plate 14 to allow floating objects to pass through, and the second separation plate 15 has a diameter of approximately 3 m/m, for example. It is made from a perforated board, and the top end of the board is submerged in water.

Further, the scraping device 9 has a scraping belt 23 stretched between a scraping transmission pulley 21 and a scraping driven pulley 22 which are rotationally driven by a drive motor 20. A scraping rake 24 is attached to the bottom of the container 9 for scraping up the accumulated waste film pieces and transporting them to the outside, and the scraping speed is set at a speed that does not generate water flow that inhibits the settling of the waste film pieces. There is. A scraped material outlet 26 is provided on the scraping conduction pulley 21 side, and a drainage nozzle 27 is provided on the scraping driven pulley 22 side. A floating object mixing prevention plate 25 is attached to prevent this.

Next, the adjustment tank 3 has a structure in which a water flow is applied in the tangential direction inside the tank, and the waste film pieces can be adjusted to a constant concentration by this hydraulic power. Further, as shown in FIG.
and a screw 6b rotating on the inner surface of the cone 6a.
It is composed of.

Incidentally, at a subsequent stage of the horizontal centrifugal dehydrator 6, there is provided a step (not shown) for drying the dehydrated waste film pieces.

Next, the operation of the above configuration will be explained.

The waste film pieces that have already been crushed in the previous process are subjected to ultrasonic irradiation in hot water and thoroughly cleaned. On this occasion,
Many pieces of waste film with wrinkles and folds are mixed in. However, simply submerging the film in water does not remove the trapped air, but irradiating the waste film with ultrasonic waves in warm water softens the waste film and stretches the wrinkles and folds, allowing the trapped air to be removed. is removed. The waste film pieces that have been thoroughly washed and from which air has been removed are fed into the tank 9 of the foreign matter separation tank 2 after being drained by the net conveyor 1a. The waste film pieces supplied into the tank 9 already filled with hot water are
The water spray nozzle 1 is submerged in warm water by the inlet guide wheel 11 while being sprayed with water by the water spray nozzle 12.
The water is dispersed and transported by the water flow sent from 3 and collides with the first separation plate 14. The waste film pieces that collide with the separation plate 14 are rapidly separated, and most of the film pieces, which have a higher specific gravity than water, settle while migrating in the downward water flow and are deposited on the upper part of the scraping driven pulley 22. Also, some of the waste film pieces, which have a specific gravity lower than that of water, float up and pass through the notch of the first separating plate 14. Furthermore, the waste film pieces that migrated in the water and could not float or settle are removed from the separation plate 14.
, and collides with the second separating plate 15 . Then, the waste film pieces that collided with the separation plate 15 are separated again, the floating material passes through the upper part of the separation plate 15, and the sediment is deposited at the lower part.

At this time, the crushed waste film pieces are usually mixed with wrinkled and double-folded film pieces, and even when these waste film pieces are submerged in water, the air trapped between them is not removed, so conventionally In the present invention, film pieces with a large specific gravity float up and are not separated, resulting in poor separation efficiency.However, in the present invention, the ultrasonic cleaning tank 1
Since the air contained in the waste film pieces has already been removed in the process, the separation and removal due to the difference in specific gravity will not be affected by air bubbles. That is, there is no possibility that the waste film pieces, which have a higher specific gravity than water, float up due to the influence of air bubbles and impair the separation efficiency from floating objects (foreign objects).

The floating objects that have passed through the second separation plate 15 in this manner are guided by the floating object discharge guide wheel 17, pass through the discharge gate 18, and are discharged from the floating object outlet 18a to the floating object drainage conveyor. On the other hand, the waste film pieces to be recycled, which are sediments from which foreign substances such as foreign films and floating matter have been separated and removed, slide down the slope of the bottom of the tank 9 and are deposited and collected on the upper part of the scraper driven pulley 22. The water is continuously taken out from the tank 9 by the device 19 and guided to the adjustment tank 3. The waste film pieces adjusted to a constant concentration in the adjustment tank 3 are supplied to the horizontal centrifugal dehydrator 6 through the transfer pipe 5 by the transfer pump 4, and are fed into the center of the cone 6a where they are subjected to the action of centrifugal force. The waste film pieces are dehydrated by being pressed against the inner wall of the cone 6a, and the dehydrated waste film pieces are transferred to the screw 6b.
It is scraped out continuously in the horizontal direction by Thus, the dehydrated waste film pieces are dried in the next drying step to become a final product for reuse with low foreign matter contamination and low water content.

In addition, since the horizontal centrifugal dehydrator 6 is used for the above-mentioned dehydration, unlike when using a conventional vertical centrifugal dehydrator, the water holes may become clogged or sand and mud may accumulate, causing the screw To allow waste film pieces to be continuously dehydrated and taken out without causing troubles such as bending and damage of screw blades due to waste film pieces being caught between wall surfaces.

As explained above, according to the present invention, pulverized waste film pieces are softened in an ultrasonic cleaning tank and thoroughly cleaned while removing the air contained therein, and then recycled in a foreign matter separation tank due to the difference in specific gravity. The waste film pieces to be used and foreign matter are separated, only the foreign matter is removed, and the waste film collected at the bottom of the tank is dehydrated using a horizontal centrifuge after concentration adjustment, so before separating the waste film from foreign matter. Since the air contained in the waste film pieces is removed, the waste film and foreign matter can be effectively separated and removed in the foreign matter separation tank, and the horizontal centrifugal dehydrator allows dehydration without the troubles of conventional methods, thus removing foreign matter. This has the effect of being able to continuously take out recycled waste film pieces with low contamination and moisture content.

Further, according to the present invention, the foreign matter separation tank is configured such that the waste film pieces supplied from the ultrasonic cleaning tank are submerged by a guide wheel and forcibly transferred to a separation area with a separation plate using a water injection nozzle. Conventionally, waste film pieces and foreign matter are separated by colliding with each other, and the settled waste film pieces are taken out by a scraping device and the foreign matter is separately discharged. Compared to the previous method, which separates foreign matter from the foreign matter, it is possible to use mechanical force to promote separation and perform separation and removal treatment in a short time.The separation capacity per volume can be extremely increased, and the foreign matter separation tank can be made smaller. Therefore, it is possible to very effectively separate and remove foreign substances such as foreign film pieces and floating matter that are mixed on the waste film pieces to be recycled, and dehydrate them, resulting in recycling with a low foreign substance contamination rate and water content. This has the effect that film pieces can be taken out continuously and the processing apparatus can be made more compact.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a separation and dehydration treatment apparatus for recycled raw material film according to the present invention, FIG. 2 is a plan view of a foreign matter separation tank that forms the main part of the present invention, and FIG. FIG. 2 is a cross-sectional view of the polyseparation tank in a plane perpendicular to the longitudinal direction in FIG. 2; 1... Ultrasonic cleaning tank, 2... Foreign matter separation tank, 3...
...Adjustment tank, 4...Transfer pump, 6...Horizontal centrifugal dehydrator, 11...Guide car, 13...Water injection nozzle,
14, 15...first and second separation plates, 18...discharge gate, 19...raking device.

Claims (1)

[Claims] 1. An ultrasonic cleaning tank for carefully cleaning waste film pieces;
From the carefully cleaned waste film pieces supplied from the ultrasonic cleaning tank, foreign substances such as foreign film pieces and floating substances adhering to the waste film pieces are separated and floated in water due to the difference in specific gravity and removed. a foreign matter separation tank for taking out the waste film pieces that have settled together; an adjustment tank for adjusting the concentration of the waste film pieces taken out from the foreign matter separation tank; and a horizontal type for dewatering the waste film pieces supplied from the adjustment tank by a transfer pump. 1. A separation and dehydration treatment device for waste film for recycled raw materials, characterized by comprising a centrifugal dehydrator. 2. An ultrasonic cleaning tank that thoroughly cleans waste film pieces;
From the carefully cleaned waste film pieces supplied from the ultrasonic cleaning tank, foreign substances such as foreign film pieces and floating substances adhering to the waste film pieces are separated and floated in water due to the difference in specific gravity and removed. a foreign matter separation tank for taking out the waste film pieces that have settled together; an adjustment tank for adjusting the concentration of the waste film pieces taken out from the foreign matter separation tank; and a horizontal type for dewatering the waste film pieces supplied from the adjustment tank by a transfer pump. The foreign matter separation tank includes a guide wheel that submerges the waste film pieces supplied into the foreign matter separation tank, and a guide wheel that disperses and transfers the submerged waste film pieces to a separation area. A water injection nozzle, two separation plates whose inclination angle and vertical mounting position can be adjusted to promote separation and sedimentation by colliding waste film fragments migrating in the water, and a discharge gate that can be opened and closed to allow separated and floated foreign matter to flow out. and a scraping device for taking out waste film pieces settled at the bottom of a foreign matter separation tank.