JP2008132484A - Magnetostriction type float sensor-used recovery control apparatus for under-screen air chamber type wet gravity sorter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recovery control technique in an under-screen air chamber type wet gravity sorter, by which the substance to be recovered can be sorted with good precision regardless of its kind. <P>SOLUTION: A recovery control apparatus, which is arranged in the under-screen air chamber type wet gravity sorter (10) provided with: a sorting chamber (12) in which the substance to be sorted is thrown; a pulsating chamber (14) positioned below the sorting chamber; and a screen (16) positioned between the sorting chamber and the pulsating chamber, is provided with a magnetostriction type float sensor (22) arranged to be extended substantially vertically in the sorting chamber. A float sliding along a rod of the magnetostriction type float sensor is formed to have desired specific gravity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention generally relates to a recovery control technique in a reticulated air chamber type wet specific gravity sorter. More specifically, the present invention relates to a recovery control device used for a reticulated air chamber type wet specific gravity sorter using a magnetostrictive float sensor.

  Plastic is used in a wide variety of fields such as automobiles, home appliances, various devices, containers, and the like, and in modern society, it cannot be realized without plastic. The amount of plastic used continues to increase year by year, and the amount of mixed plastic particles generated is increasing enormously. Under such circumstances, the use of mixed plastic particles is an important issue in forming a recycling society. In order to promote the use of mixed plastic particles as resources, it is necessary to establish a technology for selecting and reusing them as resources, and the need to select mixed plastic particles of different materials is increasing. There are a wide variety of plastic materials, which have the characteristics of low specific gravity and small difference in specific gravity.

  On the other hand, a reticulated air chamber type wet specific gravity sorter is known as a machine that selectively recovers high quality coal mainly from raw coal. With reference to FIG. 9, the principle of operation of the reticulated air chamber type wet specific gravity sorter will be briefly described. The screened air chamber type wet specific gravity sorter has a sorting chamber in which the substance to be sorted is placed above and a pulsation chamber filled with water located below, and a mesh is placed between the sorting chamber and the pulsation chamber. Has been. An air chamber for entering / exiting air is arranged in the pulsation chamber, and the water level in the sorting chamber can be raised / lowered by raising / lowering the water level in the air chamber by entering / exiting air. . Then, by applying an appropriate water pulsation to the substance placed in the sorting chamber, a layer of substances with specific gravity is formed in the sorting chamber.

  Various techniques for recovering a desired substance using a reticulated air chamber type wet specific gravity sorter have been proposed (Patent Documents 1 to 5). For example, a method for detecting and controlling the layer thickness of the recovered material by creating a float that approximates the specific gravity of the recovered material, attaching a shaft above the float, and measuring the height of the shaft that swings up and down ( A shaft oscillation type float sensor) and a method of manually controlling the recovery device by observing the recovered substance are known.

JP-A-64-43355 JP 2000-185241 A JP 2001-220192 A JP 2004-034674 A JP 2004-143575 A

However, the above-described method using the shaft swing type float sensor has the following problems.
(1) When the buoyancy including the shaft weight is required and it is going to be used for sorting materials with a low specific gravity such as plastic, the float shape becomes too large and the float cannot be accommodated in the sorting chamber. Can occur.
(2) Since the weight of the float increases and the inertial force increases, the sensitivity tends to decrease as a reaction.
(3) Since the shape of the float becomes large, it is extremely difficult to capture small pulsations.
(4) Since the shape of the float becomes large and the projected area becomes large, a large turbulent region is generated around the float, and depending on the type of the substance to be collected, there is a possibility of adversely affecting the sorting accuracy.
(5) Since the shape of the float becomes large, it is possible to cope with the case where the substance to be recovered is a large substance such as coal, but it is satisfactory when the substance to be recovered is a small one such as plastic particles. It is difficult to sort with sorting accuracy.
In addition, there is a problem that the accuracy of control is not guaranteed in the method that relies on the observation of the recovered material.
As described above, it is the actual situation that no satisfactory items can be found in the recovery control technique in the conventional reticulated air chamber type wet specific gravity sorter.

  The present invention has been devised in view of such circumstances, and recovery control in a reticulated air chamber type wet specific gravity sorter capable of sorting with good accuracy regardless of the type of substance to be collected. The purpose is to provide technology.

  The inventor of the present invention pays attention to the fact that, in the magnetostrictive float sensor conventionally used for measuring the liquid level, the float shape can be reduced from the operating principle, and the reticulated air chamber type wet specific gravity is used. A technology using a magnetostrictive float sensor for recovery control in a sorter has been developed.

An example is now given of the case where the substance 1 is selectively recovered from the material to be sorted consisting of the substance 1 (specific gravity γ ₁ ) and the substance 2 (specific gravity γ ₂ <γ ₁ ). When the float is formed so that the specific gravity γ _F of the float of the magnetostrictive float sensor becomes the average specific gravity (= (γ ₁ + γ ₂ ) / 2) of the substance 1 and the substance 2, sorting by the pulsation of water When substance 1 and substance 2 are gradually stratified by the work, the float of the magnetostrictive float sensor is theoretically positioned at the boundary surface between substance 1 and substance 2, so that substance 1 is selected with good accuracy. It becomes possible to do. In the sorting operation, it is not always necessary to place the float on the boundary surface of the substance.

  According to various experiments conducted by the present inventor, when the weight of the material to be sorted is too different (for example, when it is an order of magnitude such as 10 g and 1 kg), the material is not necessarily stratified according to the specific gravity difference. found. Therefore, in order to avoid the occurrence of such a situation, prior to the sorting work, pre-processing is performed so that the weight of the work to be sorted is not too different (specifically, the particle sizes are very different). It has been found that a good sorting operation can be carried out by eliminating the influence of the weight difference of the substances to be sorted as much as possible by removing the substances in advance).

  A recovery control device for a reticulated air chamber type wet specific gravity sorter according to claim 1 of the present application includes a magnetostrictive float sensor arranged so as to extend substantially vertically in the sorting chamber, and the magnetostrictive float sensor The float that slides along the rod is formed to have a desired specific gravity.

  The recovery control device for a reticulated air chamber type wet specific gravity sorter according to claim 2 of the present application prevents the material to be sorted from being caught in the gap between the rod and the float in the device of claim 1. Therefore, the rod is shaped so that the cross-sectional shape of the rod is a triangle.

  The recovery control device for a reticulated air chamber type wet specific gravity sorter according to claim 3 of the present application, in the device of claim 1, prevents entry of a substance to be sorted into a gap between the rod and the float. Therefore, a cylindrical tube is attached to the upper part and / or the lower part of the float so as to surround the rod.

  The recovery control device for a reticulated air chamber type wet specific gravity sorter according to claim 4 of the present application is the device according to any one of claims 1 to 3, wherein the magnetostrictive float sensor is disposed in the sorting chamber. The material to be collected is disposed in the vicinity of a discharge port through which the collected substance is discharged.

  According to the collection control device of the present invention, a desired substance to be collected can be selectively collected from a substance to be sorted with good accuracy. More specifically, in the recovery control device of the present invention, the signal can be output to the arithmetic controller while following the small (about 20 mm) and fast (about 45 Hz) pulsation well.

  In the recovery control device of the present invention, since the magnetic float sensor is small, a large turbulent region is not generated around the float, and the sorting accuracy is not adversely affected. Furthermore, in the collection control apparatus of the present invention, since the float is small, even if the material to be sorted is a small one such as glass beads, the sorting operation can be carried out satisfactorily.

  Next, with reference to the drawings, a recovery control device for a reticulated air chamber type wet specific gravity sorter according to a preferred embodiment of the present invention will be described in detail. FIG. 1 is a perspective view schematically showing a recovery control device according to a preferred embodiment of the present invention, which is used in a reticulated air chamber type wet specific gravity sorter 10. In FIG. 1, reference numeral 12 denotes a sorting chamber into which a substance to be sorted (hereinafter referred to as “substance to be sorted”) is charged, 12 a is an inlet for the sorted substance, 14 is a pulsation chamber filled with water, and 16 is a sorting chamber. A mesh disposed between the pulsating chamber 12 and the pulsation chamber 14, 18 an ejector for discharging a substance to be collected (hereinafter referred to as "substance to be collected"), and 20 a motor for driving the ejector. Yes.

  As shown in FIG. 2 (a) showing a cross section of the reticulated air chamber type wet specific gravity sorter 10, a discharge port 12 b through which a substance to be collected is discharged is provided at a position adjacent to the lower end of the sorting chamber 12. The ejector 18 is disposed adjacent to the discharge port 12b. As shown in FIG. 2B, the ejector 18 has a configuration in which a plurality of blades 18b (four in FIGS. 1 and 2) are attached to the shaft 18a, and is connected to the shaft 18a. By rotating and driving the motor 20, the blade 18b is rotated, whereby the substance to be collected located in the vicinity of the discharge port 12b is discharged. The ejector 18 itself is a known device.

  The collection control device includes a magnetostrictive float sensor 22 disposed in the sorting chamber 12 so as to extend in a substantially vertical direction. As shown in FIG. 2A, the magnetostrictive float sensor 22 includes a rod 22a, a float 22b arranged so as to slide along the rod 22a, and a head portion 22c arranged at the upper end of the rod 22a. And the lower end of the rod 22a is firmly fixed to the bottom of the sorting chamber 12.

  The float 22b of the magnetostrictive float sensor 22 is formed to have a desired specific gravity. Further, the specific gravity of the float 22b is selected so as to be larger than the specific gravity of the liquid (for example, water) that is the sorting medium, so that the float 22b floats on the liquid surface during the sorting operation. Is avoiding. The magnetostrictive float sensor 22 may be a commonly used one.

  During the sorting operation, the material to be sorted may be caught in the gap between the rod 22a and the float 22b, and the smooth sliding of the float 22b may be impaired. Therefore, in order to prevent such a situation from occurring, it is preferable to dispose a rod 22′a having a triangular cross-sectional shape and increase the gap between the rod 22′a and the float 22b (FIG. 3). (See (a)). Alternatively, a cylindrical tube 22b1 may be attached to the upper part and / or the lower part of the float 22b so as to surround the rod 22a so that the substance to be sorted does not easily enter the gap between the rod 22a and the float 22b. As this cylindrical tube, as shown in FIG. 3B, a tube provided with a plurality of small holes on the outer periphery may be used.

  In order to accurately grasp the boundary surface of the substance to be collected, the magnetostrictive float sensor 22 is preferably installed in the vicinity of the ejector 18 as shown in FIG. 2A, for example, but is not limited thereto. is not.

  The collection control device also includes a calculation controller 24. The arithmetic controller 24 is connected to the magnetostrictive float sensor 22 via a cable 26 and is connected to the motor 20 via a cable 28. In the arithmetic controller 24, the signal sent from the magnetostrictive float sensor 22 is converted into a control signal based on an existing arithmetic method (for example, moving average, deviation value, etc.), and this control signal is sent to the motor 20. The motor 20 is driven to rotate. As the arithmetic controller 24, a commonly used one may be used.

Next, recovery control by the reticulated air chamber type wet specific gravity sorter recovery control device configured as described above will be described. The substance A is selectively selected from the substance X composed of the substance A (specific gravity γ _A , indicated by “◯” in FIG. 4) and the substance B (specific gravity γ _B <γ _A , indicated by “△” in FIG. 4). Take the case of collection as an example.

In this example, the float 22b is formed so that the specific gravity of the float 22b of the magnetostrictive float sensor 22 is (γ _A + γ _B ) / 2 in order to detect the boundary surface between the substance A and the substance B after sorting. It shall be.

  First, the substance X is charged into the sorting chamber 12 through the charging port 12a (see FIG. 4A). Next, a layer of substance A and a layer of substance B are gradually formed in the sorting chamber 12 by raising and lowering the water level in the air chamber by the entry / exit of air to give pulsation of water to the substance X in the sorting chamber. (See FIG. 4 (b)). When the layer of the substance A and the layer of the substance B are formed, the float 22b slides in the rod 22a and is positioned at the boundary surface between the substance A and the substance B (see FIG. 4C). Then, a signal is sent from the magnetostrictive float sensor 22 to the arithmetic controller 24 via the cable 26, and then an operation signal is sent from the arithmetic controller 24 to the motor 20 via the cable 28. As a result, the motor 20 operates to rotate the ejector 18 and the substance A is discharged from the discharge port 22b (see FIG. 4D).

The substance X is initially in a state in which the substance A and the substance B are mixed (immediately after being introduced into the sorting chamber 12), but the substance A is given a pulsation of water and approaches the discharge port 12b. And substance B are gradually separated and stratified by the difference in specific gravity. In the above example, since the magnetostrictive float sensor 22 is installed in the vicinity of the ejector 18, the specific gravity of the float 22 b is set to (γ _A + γ _B ) / 2, which is the average specific gravity of the substances A and B. The boundary surface between the substance A and the substance B in the vicinity of the outlet 12b can be accurately detected. However, when the magnetostrictive float sensor 22 cannot be installed in the vicinity of the ejector 18 due to physical reasons or the like (for example, as shown in FIG. 4 (e), the float must be installed at the center of the sorting chamber). When the specific gravity of the float 22b is [(γ _A + γ _B ) / 2] + α, the boundary surface between the substance A and the substance B can be accurately detected.

  A comparative experiment was conducted between the case of using a magnetostrictive float sensor and the case of using a conventional shaft oscillation type float sensor. In the experiment, a magnetostrictive float equipped with a spherical magnetostrictive float with a diameter of 40 mm (see FIG. 5B, volume 14.74 cc, weight 31.05 g, specific gravity 2.106) with a 20 mm through hole in the center. Shaft swinging type equipped with a reticulated air chamber type wet specific gravity sorter with sensors and a conventional wooden float (see Fig. 5 (c), volume 2070cc, weight 4.34kg, specific gravity 2.10) A reticulated air chamber type wet specific gravity sorter in which a float sensor is arranged was prepared (as can be seen from the above example, the size of the float is significantly different even if the float has the same specific gravity).

  Alumina spheres (diameter 6.0 mm, specific gravity 2.9) are introduced into the sorting chambers of the above two reticulated air chamber type wet specific gravity sorters, respectively, so that the layer thickness is 130 mm, and then the layer thickness is 70 mm. Glass beads (diameter 6.0 mm, specific gravity 2.1) were introduced into (see FIG. 5A).

  In this state, pulsation of the same scale (frequency 45 Hz, wave height 20 mm) was given to each sorter, and the results are as shown in FIGS. 6 and 7. FIG. 6 is a photograph showing a sorting chamber in which a magnetostrictive float sensor is arranged, and FIG. 7 is a photograph showing a sorting chamber in which a conventional shaft swing type float sensor is arranged. In the case of the magnetostrictive float sensor, the float is located at the boundary between the alumina sphere layer and the glass bead layer (see FIG. 6), whereas in the case of the conventional shaft swing type float, A float is located in the layer of alumina spheres (see FIG. 7). This experiment shows that the boundary surface is detected in the case of the magnetostrictive float sensor, but the boundary surface cannot be detected accurately in the case of the conventional shaft swing type float. It was.

  The above-mentioned recovery control device was applied to a screened air chamber specific gravity sorter for waste fluorescent tube separation and purification composed of a coarse sorting section and a fine sorting section. Magnetostrictive float sensors each having a float specific gravity adjusted to 2 to 4 were arranged in the vicinity of the respective outlets of the coarse sorting section and the fine sorting section. As a result of the recovery work, it was verified that the separation and purification of lead glass, soda glass, quartz and hard glass were carried out effectively.

  The recovery control device described above was applied to the separation and purification of plastic in shredder dust. Shredder dust with a particle size of 80 mm or less in advance was removed with a net air chamber type specific gravity sorter for rough sorting, and metal, earth and sand, floated material, etc. were removed, and only plastic was put into a crusher and sized to about 10 mm. . Then, the sized plastic is put into a reticulated air chamber type specific gravity sorter in which the collection control device of the present invention is installed, and is collected under a quiet sorting condition with a pulsation of 10 to 40 Hz and a wave height of about 30 to 100 mm. As a result, it was possible to confirm complete recovery of plastic having a heavy specific gravity (about 1.3 or more).

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say, it is something.

  For example, in the above embodiment, a collection control device applied to a specific gravity sorter having a single sorting chamber has been described. As shown in FIG. 8, a plurality of (three in FIG. 8) sorting are selected. You may apply to the specific gravity control machine with which the chamber was connected in series. In such a specific gravity controller, a plurality of types of substances to be recovered can be continuously recovered.

It is the perspective view which showed typically the collection | recovery control apparatus based on preferable embodiment of this invention used for a reticulated air chamber type wet specific gravity sorter. FIG. 2A is a cross-sectional view of the reticulated air chamber type wet specific gravity sorter of FIG. 1, and FIG. 2B is a perspective view of the ejector. FIG. 3A is a view showing a modified form of the magnetostrictive float sensor, and FIG. 3B is a view showing another modified form of the magnetostrictive float sensor. It is a figure for demonstrating a series of processes of the collection | recovery operation performed using the collection | recovery control apparatus of this invention. It is the figure which showed the outline | summary of the experimental apparatus in the comparison experiment in the case where a magnetostriction type float sensor is used, and the case where a conventional shaft oscillation type float sensor is used. It is the photograph which showed the position of the float in the selection chamber at the time of using a magnetostriction type float sensor. It is the photograph which showed the position of the float in the selection chamber at the time of using the conventional shaft rocking | fluctuation type float sensor. It is the figure which showed the example applied to the specific gravity controller with which the some sorter | casing room was connected in series. It is a figure for demonstrating the operating principle of a reticulated air chamber type wet specific gravity sorter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reticulated air chamber type wet specific gravity sorter 12 Sorting chamber 14 Pulsating chamber 16 Mesh 18 Ejector 20 Motor 22 Magnetostrictive float sensor 24 Arithmetic controller 26 Cable 28 Cable

Claims (4)

A reticulated air chamber type wet specific gravity sorter comprising a sorting chamber into which a substance to be sorted is charged, a pulsation chamber located below the sorting chamber, and a mesh located between the sorting chamber and the pulsation chamber A recovery control device arranged in
A magnetostrictive float sensor is disposed so as to extend substantially vertically in the sorting chamber, and a float that slides along a rod of the magnetostrictive float sensor has a desired specific gravity. A device characterized by that. The apparatus according to claim 1, wherein the rod is formed so that a cross-sectional shape of the rod is a triangle in order to prevent a material to be sorted from being caught in a gap between the rod and the float. . In order to prevent the material to be sorted from entering the gap between the rod and the float, a cylindrical tube is attached to the upper part and / or the lower part of the float so as to surround the rod. The apparatus according to claim 1. The said magnetostriction type float sensor is arrange | positioned in the vicinity of the discharge port in which the to-be-collected substance provided in the said selection chamber is discharged | emitted, The Claim 1 characterized by the above-mentioned. apparatus.