JP5709166B2 - Small air table - Google Patents

Description

  The present invention relates to an air table, and more particularly to a small air table suitable for a separation and selection test in the recycling field.

  The air table was developed in the United States about a hundred years ago and has been developed mainly as a dry coal preparation unit. It demonstrates its power in the separation of particles with relatively low specific gravity that are close to each other in specific gravity. In recent years, this technology has been diverted and established in Japan as a sorting technology for plastic recycling. Several ideas for improving the air table have been devised. For example, a separation promoting piece is arranged on the deck to promote the selection of a looped sample (see Patent Document 1), and a baffle plate is provided on the deck. The sample is deposited at a predetermined height to improve the accuracy by extending the residence time (see Patent Document 2), and the use of various deck shapes enables the selection of minute specific gravity differences (patents) There are some which aim to improve accuracy by observing the particle lamination state on the deck surface with a CCD camera and appropriately adjusting the movable partition plate (see Patent Document 4). However, these are all ideas for improving accuracy in actual operation.

JP-A-6-285432 JP 2000-126693 A JP 2002-136924 A JP 2009-125706 A

Since the air table separates the separated particles themselves as a fluidized bed, and there is only a continuous type device due to its structure, many samples are required even for a relatively small device. For example, in the lineup of Triple s Dynamics Co., Ltd. (USA), which is a development manufacturer, even the smallest device with a deck area of 0.1376 m ² requires a sample of several liters in the usual method. However, many other batch-type R & D separation test apparatuses that do not employ a fluidized bed can be tested with a sample of 100 g or less. Therefore, as a test apparatus used in a research institution, an existing air table requires a considerably large amount of sample even for the smallest apparatus. In the case where only a small amount of sample is obtained for research, this does not allow verification of the sorting effect by the air table, which is a detrimental effect in judging whether sorting by the air table is possible. In the past, small air tables have been manufactured for exhibition purposes, but this is simply a reproduction of the movement of the device and does not have a function to verify sorting characteristics for research purposes. In addition, the motion of particles thrown into the air table is very complicated, and the motion cannot be accurately predicted by calculation. For this reason, it is difficult to easily calculate machine conditions and sorting conditions for miniaturization while maintaining the same separation accuracy as existing equipment, and there is a need for miniaturization. There is no.

  In order to solve the above problems, the small air table of the present invention is characterized by having a function of verifying sorting characteristics for research.

  According to the small air table of the present invention, it becomes possible to perform an air table sorting test with a small amount of sample of 100 g or less, and for an object for which only a few samples have been available so far, Applicable characteristics can be evaluated.

The figure which showed the typical small air table deck design of this invention. The perspective view explaining the principal part of the small air table of this invention. The figure which showed the example of creation of the small air table deck of this invention.

The present inventors conducted a sorting test using the smallest air table (deck area 0.1376 m ² ) of Triple S Dynamics (USA) and a smaller deck obtained by dividing a part of the deck. . In this test, in which a part of the deck was separated and sorted, the separation accuracy equivalent to that obtained when sorting was performed with the standard sample amount using the entire deck was satisfied. It was verified whether it was possible to select
One of the particle conditions in which air table sorting works most effectively, a standard sample of flat cylindrical resin particles having a particle size of about 3 mm and a specific gravity of 0.9 to 1.4 is used. 1376m ²⁾ and the deck area of about 0.08 m ^2, separated a part of the ^{deck, 0.05m 2, 0.04m 2, 0.03m} 2, 0.02m 2, 0.01m 2, 0.0016m 2, Several hundreds of in-depth separation tests were performed on various small decks of 0.0004 m ² .

As a result, it has been found that there is a selection condition that can achieve a separation efficiency of 95% if the area is 0.02 m ² or more, and a separation efficiency of 90% if the area is 0.01 m ² or more. That is, if the following certain sorting conditions are prepared, even a small deck having a deck area of 0.02 m ² having a deck area of 1/6 or less of the original, a commercially available minimum type deck (deck area 0.1376 m ^2). ) And a sample amount at this time can be 100 g or less (the required minimum sample amount is about 60 g when tested with various resin particles having a specific gravity of 0.9 to 1.4). I found. However, if the deck area is smaller than about 0.01 m ² , the area where the particles are sized becomes insufficient, the region of heavy products and light products becomes unclear, and the separation efficiency decreases. For example, we are in the experimental example in which the separation efficiency of 40% at 0.0016M ^2, was a separation efficiency of 17% at 0.0004m ^2.
In addition, when considering the shape of the deck, in the size of about 0.03 m ² , the trapezoidal shape of the upper base: lower base: height = 1: 3: 2 similar to the original, slightly horizontal 1: 3 : 1.4, the separation efficiency was found to be 95% or more, but the separation efficiency decreased when it became longer than the similar shape, and at 1: 3: 9.5, the maximum separation efficiency decreased to about 80%. Thus, it was concluded that the difference in deck shape does not have a significant effect on the separation efficiency, but that an extremely vertically long shape is inappropriate.
For example, typical sorting conditions for a separation efficiency of 95% or more in a 0.03 m ² deck are as follows. This is the optimum selection condition for the resin particles having a particle diameter of about 3 mm (specific gravity: 0.9 to 1.4), which is the best at the air table. These conditions vary depending on the physical properties of the selected particles, but a range of about ± 50% around the following values may be considered as the movable conditions.
(1) Deck conditions Minimum area 0.03m ²
Side slope: 2 °
End slope: 6.3 °
(2) Vibration conditions Displacement: 7 mm (Amplitude: 3.5 mm)
Vibration angle (angle between installation plane) 48 °
Frequency 10Hz
(3) Airflow condition Wind speed 1.7 ~ 2.1m / sec

The above is a result of partial use of the smallest air table deck of Triple S Dynamics, Inc. (USA), but the device of the present invention has a deck area of 0.0004 to 0.08 m ² that embodies it. It is a small air table having a notebook-sized installation area with a deck (see FIG. 1). Since it has a movable range that can cover the above selection conditions, when particles with a specific gravity of about 0.9 to 1.4 are targeted, a separation test can be performed even with a sample amount of 100 g or less (the required sample amount is 0.0004 m ² ). The separation efficiency is approximately 1 g), and the separation efficiency is equivalent to that of a commercially available minimum type air table. Each condition is as follows.

(1) Deck conditions Deck area 0.0004 to 0.08m ²
Side slope: 2 ° ± 50% (movable from 0 to 10 °)
End slope: 7 ° ± 50% (movable from 0 to 10 °)
(2) Vibration conditions Displacement: 7mm ± 50% (Amplitude: 3.5mm ± 50%)
Vibration angle 48 ° ± 50%
Frequency 10Hz ± 50%
(3) Airflow conditions Wind speed 1.7m / sec ± 50%
Note that the side slope is the left oblique side of the trapezoidal deck in FIG. 2 (in FIG. 1, the angles formed by the upper base, the lower base, and the left oblique side are all right angles, but they are not necessarily perpendicular). The slope angle and end slope are the slope angle between the bottom of the trapezoidal deck and the horizontal plane in Fig. 2. The trapezoidal deck as a whole is horizontal with respect to the horizontal plane so that the lower left corner of the trapezoidal deck in Fig. 2 is the lowest position. Inclined. Then, the sample is supplied to the upper bottom side of the trapezoidal deck, separated on the lower bottom side, and discharged. In addition, as shown in FIG. 2, the vibration angle of 48 ° is an angle that the vibration direction of the deck surface makes with the installation horizontal plane when viewed from the bottom side, and the airflow is from below the deck surface made of wire mesh. It spouts upwards. Further, the riffles A to C in FIG. 1 have a height similar to that of the vibration displacement, and serve to provide a time for temporarily damming the particles to promote stratification by flow. In addition, a clearance for promoting the discharge of light products is provided on the left oblique side, and a clearance for promoting the discharge of heavy products is provided on the right oblique side. Here, most of the light products are discharged over the riffle, so the gap on the left oblique side can be omitted, but the gap on the right oblique side is the only discharge (recovery) route for heavy products. Because it is, it cannot be omitted.

FIG. 3 is a design example of a small air table that satisfies all the above conditions.
Note that the deck area, in a standard sample of the previous year, as a range obtained 95% separation efficiency has been set to 0.02～0.08M ^2, you can clear this condition as long 0.08 m ² or more If it is obvious and the separation efficiency is not 95%, an optimum separation result corresponding to each deck area can be obtained under the above-described sorting conditions even in a deck area of 0.02 m ² or less. On the other hand, paying attention to the minimum required sample amount based on the standard sample, the smaller the deck area, the smaller the sample amount, and it is possible to determine the sorting accuracy with a sample of 100 g or less stably with a deck area of approximately 0.02 m ^2. It becomes possible.

  Since the present invention is small and can select a small amount of sample of 100 g or less, it can be used as a test apparatus in a university or a research institution, and can be used for separation characteristic evaluation for a small amount of sample of 100 g or less. it can.

Claims (1)

A small air table for separation and sorting having a trapezoidal deck with a deck area of 0.01 to 0.05 m ² , characterized in that it has the following conditions (1) to (3): .
(1) Deck conditions Upper base: Lower base: Height = 1: 3: 2 to 1: 3: 1.4 trapezoid Side slope: 2 ° ± 50%
End slope: 7 ° ± 50%
(2) Vibration conditions Displacement: 7 mm ± 50%, that is, amplitude: 3.5 mm ± 50%
Vibration angle 48 ° ± 50%
Frequency 10Hz ± 50%
(3) Airflow conditions Wind speed 1.7m / sec ± 50%