JPH10202139A - Method and apparatus for removing light substances mixed in gravel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove a light substance such as a wood chip, roots of plants and pumice which are mixed into gravel (train diameter mainly is 5-25mm) sorted in an aggregate production plant and are unsuitable for an aggregate and are lighter than gravel but sink in water. SOLUTION: Gravel 13 mixed with a light substance 15 is settled into water in a classification tank 1 like a curtain having a constant layer thickness. The light substance 15 mixed into gravel 13 being settled is purged together with air bubbles to the outside of a gravel layer by sending a jet air bubbles flow which perforates the gravel layer at a prescribed angle in a rage within 45-135 degrees for the settling direction. Thereafter, light substance 15 is raised by buoyance of the air bubbles and the upwelling current of water being caused in the classification tank and overflowed together with water from an overflow weir 5. Gravel grains, which have been purged from light substance 15 and have large specific gravity, are allowed to fall in the lower part of the classification tank 1. Gravel free from light substance 15 and becoming an aggregate 14 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a gravel (having a particle size of mainly 5 to 25) which is washed and sorted in an aggregate production plant.
mm) that are not suitable as aggregates and are lighter than the gravel, such as wood chips, plant roots, pumice stones, etc., but can efficiently remove even light substances that sink into water. The present invention relates to a removal method and an apparatus suitable for performing the method.

[0002]

2. Description of the Related Art Among aggregates used for concrete in the civil engineering and construction industries, gravel having a particle size of mainly 5 to 25 mm is the most in demand. The production of such aggregates is roughly classified into a method of crushing and sorting mountain rock to obtain crushed stones, and a method of collecting natural gravel and sand, washing and sorting. Of these, natural gravel and sand raw materials have been mostly collected from rivers in the past.However, from the viewpoint of protection of rivers, most rivers are now banned from collecting natural gravel and sand. The mainstream is gravel collected from gravel layers of mountains formed from old rivers and seabed uplifts.

[0003] In collecting these natural gravel, various foreign substances that are unsuitable as aggregates due to their properties, such as debris of driftwood, plant roots, pumice stones, and small pieces of plastic and sheets, are mixed due to the characteristics of the collection site. You can't avoid doing it. Such foreign substances include not only those that are lighter than water and float on water, but also light substances that are lighter than gravel but sink in water.
The use of gravel with such foreign matter mixed therein will cause deterioration in the quality and strength of concrete. In recent years, aggregate production plants using natural gravel as raw materials
In order to improve the quality of gravel, dust removal machines have been installed to remove these foreign substances, but they are all lighter than water and only foreign substances that float on water are separated and removed using buoyancy against water. This method has the drawbacks that its removal efficiency is limited and that light substances that are lighter than gravel but sink in water cannot be removed.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, improves the efficiency of removing light substances as foreign substances mixed into natural gravel, and reduces light substances which are lighter than gravel but sink in water. It is an object of the present invention to provide a method for removing light substances mixed in gravel having a function of removing the same and a device suitable for carrying out the method.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the gravel mixed with light substances is provided with an overflow weir at the top. Is settled in the form of a curtain with a certain thickness in the water in the classification tank where the water is overflowing.
After sending a jet bubble flow through the gravel layer at a predetermined angle within the range of ~ 135 degrees to expel light substances mixed in the settling gravel out of the gravel layer together with the bubbles, the buoyancy and classification of the bubbles The light substance is raised by the upward flow of water generated in the tank and overflows from the overflow weir together with the water, and the gravel particles having a high specific gravity that have expelled the light substance are dropped below the classification tank to remove the light substance. It was completed by investigating that light substances mixed into the gravel can be effectively removed by a method of obtaining the removed gravel.

In this method, when the gravel from which light substances have been removed is carried out from the water, the gravel falling below the classification tank is carried out by a gravel carrying conveyor facing the gravel outlet opening. Gravel from which light substances have been removed can be easily discharged out of the classification tank as aggregate, and water overflowed from the overflow weir is supplied to the classification tank after removing the light substances contained therein. It was also determined that if used as circulating water for wastewater treatment, it could be economically treated.

Further, as an apparatus for carrying out this method, a sedimentary passage for gravel mixed with light substances settled in a curtain shape is formed, and the gravel mixed with light substances in the sedimentation passage is settled in a curtain shape. A jet bubble that penetrates the gravel layer at a specified angle within a range of 45 to 135 degrees to the sedimentation direction of the gravel layer that sinks down the settling path over the entire width of the gravel that is settled on one side across the gravel layer A bubble flow generating device for generating a flow is installed, and a bubble path in which bubbles from the jet bubble flow float is formed on the other side with a gravel layer to be settled down the settling path, and water is constantly provided at the top. A spill overflow weir is provided, a classification tank with a gravel exit opening at the bottom of the sedimentation channel, and a curtain with a certain layer thickness above the sedimentation channel of the classification tank. hand And a flooding gutter for draining the water overflowing from the overflow weir of the classification tank, and a gravel exit device for introducing the gravel mixed with the pollutants into the classification tank. It has also been found that an apparatus having a gravel carrying conveyor installed facing the surface is suitable.

Further, if two sedimentation paths are formed in the classification tank, and a bubble flow generator, a bubble path, and an overflow weir are provided in each of the sedimentation paths, the classification processing capacity can be increased. In this case, if the gravel outlet opening at the bottom of each sedimentation path is shared, two sedimentation paths can be formed with a simple configuration, and a large number of bubble flow generators are provided at predetermined intervals in the longitudinal direction. An orifice pipe having an orifice is installed in parallel with and horizontal to the gravel layer to be settled, and the orifice pipe is provided with a check valve and at least a flow control valve. The light substance can be easily removed from the gravel mixed with the light substance in correspondence with the gravel of various sizes, and furthermore, a plurality of orifice pipes are provided in the sedimentation direction of the gravel layer settling down the sedimentation passage. interval When separated, the jet bubble stream can be sent over a wide area to the sedimentary gravel layer to increase the classifying capacity, and the sedimentary channel is adjacent to the sedimentary gravel layer in its longitudinal direction. If an orifice tube is installed in which the orifices eject bubbles at different angles, a large amount of fine bubbles can be sent without interfering with the jet bubble flows ejected from adjacent orifices. They also found that light substances could be removed efficiently.

Further, a foreign matter removing sieve for removing light substances contained in the overflow water drained from the overflow water gutter is provided, and the overflow water from which the light substances have been removed by the foreign matter removing sieve is placed in a classification tank. If an overflow water circulation mechanism is installed, the amount of water used can be saved, and the gravel mixed with light substances input from the gravel input device will immediately flow into the overflow weir from the upper part of the bubble channel. If the partition plate for preventing is provided at the position that regulates the thickness of the gravel layer in the upper part of the classification tank, the gravel layer can be reliably formed into a curtain with a certain thickness, and the classification processing capacity If the circulating water tank of the overflow water circulation mechanism is provided with a make-up water valve for replenishing water, the water level in the classification tank can be maintained at a desired level and the classification tank can be maintained. To maintain the mud concentration in the water at a low level. That it is also to that investigation combined that can be easily performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for removing light substances mixed in gravel and an apparatus suitable for carrying out the method according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory longitudinal sectional view schematically showing an embodiment of the apparatus of the present invention suitable for carrying out the method of the present invention, FIG. 2 is an enlarged sectional view of a portion A in FIG. 1, and FIG. FIG. 4 is a sectional view corresponding to FIG. 3 showing another embodiment of the apparatus of the present invention, and FIG.
Is a sectional view corresponding to FIG. 2 showing still another embodiment of the apparatus of the present invention, FIG. 6 is a front view showing an example of an orifice pipe used in a bubble flow generator, and FIG. FIG.

In the drawing, reference numeral 1 denotes a classification tank for removing light substances 15 from gravel 13 collected from a place where the light substances 15 are mixed, such as driftwood fragments, plant roots, pumice stones, plastic and sheet fragments, and the like. A settling path 2 is formed in which the gravel 13 mixed with the light substance 15 is settled in a curtain shape.

Reference numeral 3 denotes a gravel 13 in which a light substance 15 is mixed in the sedimentation passage 2 and which is provided on one side of the gravel layer which is settled in a curtain shape. The gravel 13 extends over the entire width of the settled gravel layer. 45-135 to the settling direction of the layer
Bubbles for sending a jet bubble flow through the gravel layer at a predetermined angle in the range of degrees to generate a jet bubble flow for pushing out light substances mixed in the settling gravel with the bubbles out of the gravel layer A flow generator, and a plurality of orifices 3a at predetermined intervals in the longitudinal direction as in the illustrated embodiment.
An embodiment is shown in which the orifice pipe 3a forming a is installed parallel and horizontal to the gravel layer to be settled.

The jet bubble flow generated by the bubble flow generator 3 is such that the energy of a single bubble is large and the gravel suitable for the aggregate 14 is greatly affected by the bubbles when sent to the gravel layer. Since the action of pushing out the light substance 15 out of the gravel layer becomes small only by changing the orbit of the gravel layer which settles in the vertical direction, the bubbles are preferably fine, so that the orifice 3aa has a circular shape,
It is preferable to adopt a shape having a small opening area such as a square shape and to form a large number of them at predetermined intervals in the longitudinal direction.
Also, as described above, it is not preferable that the gas ejected from the orifice 3aa coalesce into large bubbles, so that the orifice 3a adjacent in the longitudinal direction of the orifice tube 3a is not preferable.
If an orifice tube 3a is formed so that a can emit bubbles at different angles, a large amount of fine bubbles can be sent without interfering with the jet bubbles flowing from the adjacent orifices 3aa. As shown in FIGS. 6 and 7, two rows of orifices 3a parallel to the longitudinal direction can be efficiently removed.
It is preferable that the group a is formed in a staggered state so that the orifice 3aa is shifted between the adjacent orifices 3aa of the group of orifices 3aa in the other row. Also, as in the illustrated embodiments, the plurality of orifice pipes 3a are installed at intervals in the direction of sedimentation of the gravel layer settling down the sedimentation path 2, which causes a large amount of jet bubble flow to the settling gravel layer. It can be sent and is preferred.

The bubble flow generating device 3 generates a jet bubble flow having a desired energy capable of driving the light substance 15 mixed in the gravel 13 out of the gravel layer together with the water. When the supply pressure of the compressed air is extremely high, it is necessary to provide a pressure adjusting valve 3d for adjusting the pressure of the compressed air, but regardless of the presence or absence of the pressure adjusting valve 3d, at least the compressor 3b supplies the compressed air supplied to the orifice pipe 3a. It is preferable that a flow control valve 3c for adjusting the flow rate of air be provided and a check valve 3e be provided. When a plurality of orifice pipes 3a are arranged in parallel, as shown in FIG. The orifice pipe 3a is provided with a flow control valve 3c. When the flow control valve 3c is provided in this manner, the flow control valve 3c can be used without replacing the orifice pipe 3a provided in the classification tank 1.
The size of the particles to be classified can be changed by the above operation, so that it is possible to easily cope with gravel 13 of various sizes, and if the check valve 3e is provided, When the operation is stopped, it is possible to prevent foreign matter from entering the orifice 3aa and closing the orifice 3aa.

Reference numeral 4 denotes a gravel layer formed on the other side of the gravel layer of the sedimentation passage 2 in which the gravel 13 mixed with the light substance 15 is settled in a curtain shape. This is a bubble path in which bubbles penetrating through the bubble float. The inner surface of the sedimentary channel 1 forming the bubble channel 4 opposite to the bubble flow generator 3 across the gravel layer of the sedimentation channel 1 is formed as an inclined surface which is inclined in a direction away from the gravel layer as going upward. Light substances displaced from the gravel layer
It is preferable because the bubble path 4 can be surely raised and overflowed from the overflow weir 5 described later together with water.

Reference numeral 5 denotes an overflow weir provided above the bubble path 4 in the sedimentation passage 2, and reference numeral 6 denotes a gravel 13 mixed with light substances 15 introduced from a gravel charging device 8 described below to settle the sedimentation passage 2. This is a partition plate for preventing the water from immediately flowing into the overflow weir 5 from the upper part of the bubble passage 4 without being provided. The partition plate is provided at the upper part of the classification tank 1 at a position defining the layer thickness of the gravel layer as in the illustrated embodiment. Have been.

Reference numeral 8 denotes a gravel loading device installed above the classification tank 1 for introducing the gravel 13 mixed with the light substances 15 into the sedimentation passage 2 of the classification vessel 1. As shown in FIG. 1, the gravel 13 mixed with the light substance 15 is put in the classification tank 1 in the width direction so that the gravel 13 put into the tank 1 forms a curtain having a certain layer thickness and sinks down the settling path 2. A feeder 8a that feeds the gravel 13 mixed with the light substance 15 into the feeder 8a, and a feeder 8b that feeds the gravel 13 mixed with the light substance 15 to the feeder 8a.
A structure in which a vibrator is installed and the gravel 13 supplied in a non-uniform state in the width direction from the gravel carrying conveyor 8b can be evenly leveled by the applied vibration can be shown. The gravel 13 mixed with the light substance 15 may be directly charged into the sedimentation passage 2 of the classification tank 1 by the gravel charging device 8, but as shown in FIG.
It is preferable that a holding portion for the gravel 13 is formed near the upper portion, and that the gravel 13 inserted in the holding portion is temporarily held to loosen the momentum of falling, and then guided to the sedimentation path 2.

Reference numeral 9 denotes an overflow water gutter for draining water overflowing from the overflow weir 5, and reference numeral 10 denotes an overflow water circulation mechanism for repeatedly circulating the water drained by the overflow gutter 9 as circulation water for the classification tank 1. Yes, foreign matter removing sieve 10 for removing light substances 15 contained in overflow water drained from overflow water gutter 9
a, a circulating water tank 10b for storing overflow water from which light substances 15 have been removed by the foreign matter removing sieve 10a, and a circulating pump 10c for supplying water from the circulating water tank 10b to the classification tank 1.

Reference numeral 11 denotes a classification tank which is installed facing the position just below the gravel outlet opening 7 of the classification tank 1 and whose upper part is exposed above the water surface and from which light substances 15 are removed, as aggregates 14. 1. A conveyor for gravel discharge to be discharged outside,
Since the lower end thereof is installed so as to face directly below the gravel outlet opening 7 of the classification tank 1, the rotating shaft in a portion existing in the water is mounted on the classification tank 1 via a water sealing mechanism. Various conveyors such as a belt conveyor, a screw conveyor, and a bucket conveyor can be used as long as they can carry out only the gravel as the aggregate 14 from which the light substances 15 have been removed. Reference numeral 12 denotes a replenishing water valve for replenishing water when the water level in the circulating water tank 10b is lower than a desired water level or when the mud concentration of water in the classification tank 1 becomes high.

In the apparatus of the present invention configured as described above, it is preferable that two settling paths 2 are formed in the classification tank 1 as described above because the classification processing capacity can be increased. As shown in FIG. 4, for example, as shown in FIG. 4, a large number of partition plates are provided to guide the gravel 13 mixed with the light substance 15 introduced from the feeder 8a of the charging device 8 into the center of the classification tank 1 in the width direction. 2c 8c
Are formed, and the sedimentation passages 2 are formed on both sides in the width direction of the classification tank 1, or the sedimentation passages 2 are partitioned at positions spaced from the rear end in the longitudinal direction as shown in FIG. A partition plate 2a is provided, and a two-way divider 8c composed of a large number of partition plates for guiding the gravel 13 mixed with the light substance 15 is formed on the rear end side in the longitudinal direction and the partition plate 2a side. Thus, it is possible to show an embodiment in which the sedimentation paths 2 and 2 are formed at intervals in the rear end portion in the longitudinal direction. In this case, each settling path 2 is provided with a bubble flow generator 3, a bubble path 4, and an overflow weir 5, respectively. Also, the classification tank 1
When two sedimentation paths 2 and 2 are formed therein, it is preferable that the gravel outlet opening 7 at the bottom of the sedimentation paths 2 and 2 is shared because the structure can be simplified.

The operation of carrying out the method of the present invention using the above-described apparatus of the present invention will be described in detail below. First, gravel 13 collected from a collection site mixed with light substances 15 such as driftwood debris, plant roots, pumice stones, plastic and sheet fragments, etc., is supplied to a feeder 8a from a gravel carrying conveyor 8b of a gravel input device 8. Then, it is put into the sedimentation passage 2 of the classification tank 1 and settled in a state where it is evenly distributed in the width direction by the feeder 8a. At this time, if a storage part is formed near the upper part of the sedimentation path 2 of the classification tank 1, the gravel 13 injected from the gravel charging device 8 is temporarily relaxed in the storage part and then settles down the sedimentation path 2. The sediment 13 can be settled substantially vertically and at a low speed.
13 can be reliably settled in the form of a curtain having a constant layer thickness.

When the gravel 13 mixed with the light substance 15 which settles down in the sedimentation path 2 to form a curtain-like gravel layer and reaches the bubble flow generator 3, the orifice pipe 3a of the bubble flow generator 3 From the orifice 3aa, compressed air having a predetermined pressure higher than the water pressure at that position is sent as a jet bubble stream having a predetermined flow rate penetrating the gravel layer at a predetermined angle within a range of 45 to 135 degrees with respect to the sedimentation direction of the gravel layer. Gravel settling
The light substance 15 mixed in 13 together with air bubbles outside the gravel layer,
That is, it is driven out to the bubble path 4 formed on the side of the gravel layer opposite to the bubble flow generator 3. Here, the angle of the jet bubble flow with respect to the sedimentation direction of the gravel layer is set to the predetermined angle within the range of 45 to 135 degrees. If the angle is smaller than 45 degrees, the vertically downward component of the energy of the jet bubble flow is large, and Since the effect of accelerating the sedimentation velocity of the sand is large and the horizontal component necessary for penetrating the gravel layer is small, not only the jet bubble flow cannot efficiently penetrate the gravel layer, but also the light substance 15 to be expelled to the bubble path 4 This is because the phenomenon of sedimentation occurs, and if it is greater than 135 degrees, the energy of the jet bubble flow has a large vertical upward component, so the effect of slowing down the sedimentation speed of the settling gravel is large and penetrates the gravel layer This is because the required horizontal component is small and the jet bubble flow cannot efficiently penetrate the gravel layer.

That is, the gravel 13 mixed with the light substance 15 is settled in the form of a curtain having a certain layer thickness in water, and settles. When the jet bubble flow penetrating through the gravel layer at a predetermined angle within the range described above, the gravel that becomes the aggregate 14 having a large specific gravity settles substantially in the vertical direction, and the light substance 15 having a specific gravity smaller than the gravel that becomes the aggregate 14 Is driven out of the gravel layer in the process of subsidence with the bubble stream by the energy of the jet bubble stream.

The light substance 15 expelled out of the settling gravel layer passes through the bubble path 4 formed on the side of the curtain-shaped gravel layer opposite to the side where the jet bubble flow is generated. The water is raised by the upward flow of water generated therein and overflows together with the water from the overflow weir 9 provided at the upper part of the bubble passage 4 together with the water.

The inner surface of the bubble passage 4 on the opposite side of the bubble flow generating device 3 across the gravel layer of the sedimentation channel 2 is formed in an inclined surface which is inclined away from the gravel layer as going upward. When the number of orifice tubes 3a is plural, the bubble amount increases from the bottom to the top, so that the rising speed of water and bubbles is lower than the sedimentation speed of the light substance 15 so that the rising flow rate due to the bubble amount becomes substantially constant. Can be slightly increased, so that the light substance 15 can be surely overflown from the overflow weir 5.

Here, the orifice 3aa of the orifice tube 3a
The flow rate of the compressed air to be ejected from is a flow rate that can expel the light substance 15 out of the gravel layer together with the jet bubble flow without hindering the sedimentation of the gravel serving as the aggregate 14 in a substantially vertical direction, The pressure of the compressed air corresponding to the water depth where the orifice pipe 3a is installed, the size of the gravel as the aggregate 14,
It is appropriately set according to conditions such as the specific gravity and size of the light substance 15 and the size of the orifice 3aa formed in the orifice tube 3a.

If a plurality of orifice pipes 3a are installed at intervals in the vertical direction as the bubble flow generating device 3, the jet bubble flow can penetrate a wide range with respect to the settling gravel layer. Therefore, the light substance 15 can be reliably and efficiently driven out of the gravel layer. In this case, in order to keep the energy of the jet bubble flow from each of the orifice pipes 3a constant at any depth, the flow rate regulating valve 3c is used to set a small flow rate in the orifice pipe 3a installed on the shallow side of the water depth, By setting a large flow rate in the orifice pipe 3a installed on the deep side of the water depth, a jet bubble flow having a constant energy can be generated at any depth, so that lightness classified by the depth can be obtained. The size of the substance 15 is not different, and only the predetermined light substance 15 can be removed,
You can get high quality gravel as 14.

When the orifice pipe 3a is formed such that the orifice 3aa, which is adjacent to the gravel layer settling down the sedimentation channel 2 in the longitudinal direction, ejects bubbles at different angles, the orifice 3a is adjacent to the gravel layer. Since it is possible to prevent the jet bubble flows injected from the orifice 3aa from interfering with each other to form large bubbles, a large amount of fine bubble jet bubble flows can be generated, and the gravel suitable for the aggregate 14 is substantially vertically. Only the light substances 15 can be driven out of the gravel layer without sinking and changing the trajectory of the gravel layer.

For example, three orifice pipes 3a each having an outer diameter of 34 mm are provided on a vertical surface in the sedimentation passage 2 of the classification tank 1 at a water depth of 30 mm.
0 mm, 425 mm and 550 mm are arranged side by side with their longitudinal directions horizontal. Each orifice pipe 3a has an orifice 3aa with a diameter of 1.0 mm in the direction of sedimentation of gravel as aggregate 14.
Orifices 3aa formed in two rows with different ejection angles of 7.5 degrees and 112.5 degrees, and adjacent in the longitudinal direction in each row
Are located at a distance of 60 mm, and the orifice 3 of the other row is positioned at the center between adjacent orifices 3aa of one row when viewed from above.
aa are formed in a staggered position, and the inner surface on the opposite side of the gravel layer of the sedimentation channel 2 of the classification tank 1 is inclined in a direction away from the gravel layer as it goes upward at an angle of 20 degrees. The distance from the orifice tube 3a to this inner surface is 270 mm, 225 mm and 18 mm, respectively, from the shallower water depth.
Each orifice when a gravel 13 mixed with a light substance 15 is introduced into a sedimentation passage 2 of a classification tank 1 configured to be 0 mm in order to obtain a gravel serving as an aggregate 14 having a particle size of 5 mm or more. The pressure of compressed air ejected from tube 3a is 4.9 × 10 ⁴ Pa
When the flow rate is adjusted by the flow rate control valve 3c at a constant rate, the gravel serving as the aggregate 14 is settled substantially vertically as a jet bubble flow from the bubble generating device 3 and only the light substances 15 are driven out of the gravel layer and the bubble path 4 is formed. Together with the bubbles.

Here, not only the light substance 15 but also small-size gravel is expelled out of the gravel layer together with the bubble flow, but the substance expelled out of the gravel layer has its sedimentation velocity and rising velocity of water. And those that settle and those that rise in relation to the buoyancy of the bubbles. The gravel particles having a large specific gravity that have been expelled from the light substances 15 in this manner, that is, the gravel particles that have settled while forming a gravel layer and the gravel particles that have been driven out of the gravel layer and subsequently settled are placed below the classification tank 1. It falls and removes the light substances 15, and becomes gravel suitable for the aggregate. Also, small particles rising in the bubble path under the influence of the rising velocity of the water and the buoyancy of the bubbles are caused to overflow from the overflow weir 5 together with the rising water flow of the water, and to the classification tank 1 by the overflow water gutter 9.
It is discharged outside.

If the two sedimentation paths 2 are formed in the classification tank 1, the classification processing capacity can be doubled, so that the classification processing efficiency is very excellent. Gravel exit opening 7 provided at the bottom of the sedimentation path 2
Is preferably shared.

Light substances 15 introduced from the gravel introduction device 8
The partition plate 6 for preventing the gravel 13 mixed with the sediment from flowing into the overflow weir 5 immediately from the upper part of the bubble channel 4 without sinking down the sedimentation path 2 is provided with a thickness of the gravel layer at the upper part of the classification tank 1. When it is provided at the prescribed position, the gravel layer can have a constant thickness, so that the jet bubble flow generated by the bubble flow generator 3 can penetrate the gravel layer in a constant state, and The substance 15 can be reliably pushed out of the gravel layer, and the gravel serving as the aggregate 14 can be prevented from being discharged from the overflow weir 5 without sinking down the sedimentation passage 2.

Further, a foreign matter removing sieve 10a for removing light substances 15 contained in the overflow water drained from the overflow water gutter 9 is provided, and the overflow water from which the light substances 15 have been removed by the foreign matter removing sieve 10a is removed. Overflow water circulation mechanism to supply to classification tank 1
If 10 is installed, the light substance 15 is removed by the foreign matter removing sieve 10a, stored in the circulating water tank 10b, and then supplied to the classification tank 1 by the circulating pump 10c, so that water can be used repeatedly. It is.

The water discharged out of the classification tank 1 together with the light substances 15 and the gravel as the conveyer 11 for carrying out the gravel and the gravel as the aggregate 14 carried out by the conveyor 11 for carrying out the gravel are put out of the classification tank 1. The overflow water circulation mechanism 10
When the water level in the circulating water tank 10b drops, the make-up water valve 12 is opened to supply water into the circulating water tank 10b, and when the mud of the gravel 13 mixed with the light substance 15 is large, the circulating water Water is replenished to prevent an increase in the attached mud content of the product aggregate 14 due to an increase in the concentration.However, if the circulating water tank 10b is provided with a make-up water valve 12 for refilling water, Operations can be performed. Here, the surplus circulating water overflows from the circulating water tank 10b and is discharged from the overflow water circulating mechanism 10 to the outside.

The gravel that has been removed from the light material 15 and settled to the bottom in the classification tank 1 is removed from the classification tank 1 by, for example, the gravel discharge conveyor 11 facing the gravel exit opening below the settling path 2 of the classification tank 1. The gravel suitable for the aggregate 14 from which the light substances 15 have been removed can be obtained.

[0036]

As described in detail above, the method for removing light substances mixed in gravel according to the present invention is characterized in that a gravel mixed with light substances is provided with an overflow weir at the top, and the overflow weir is always provided from the overflow weir. A jet that penetrates the gravel layer at a predetermined angle within a range of 45 to 135 degrees with respect to the direction of settling in a curtain with a certain layer thickness and settles in the water in the classification tank where the water is overflowing. After sending the bubble stream to expel the light substances mixed in the settling gravel out of the gravel layer together with the bubbles, the light substances are raised by the buoyancy of the bubbles and the upward flow of water generated in the classification tank. As the gravel particles with a high specific gravity, which has expelled light substances, are dropped below the classification tank, the specific gravity is higher than that of water. Not only small light substances, but also as aggregate Unsuitable substances such as driftwood chips, plant roots, pumice stones, plastics and sheet chips that contain water can be efficiently removed. Since the material is removed, the gravel is rewashed, so that very high quality gravel can be obtained.

As an apparatus of the present invention suitable for carrying out the method of the present invention exhibiting the above-mentioned excellent effects, if an overflow water circulation mechanism is provided, water can be used effectively and it is economical. is there. In addition, the overflow water circulation mechanism is constituted by the water adhering to the light substances and discharged out of the classification tank and the gravel carrying conveyor and the water adhering to the gravel carried out by the conveyor and discharged out of the classification tank. Although the water level in the circulating water tank falls, if a make-up water valve is installed, it is possible to operate this make-up water valve to supply water until the water level in the circulating water tank reaches a desired water level, Gravel light substances can be efficiently removed with little water.

Furthermore, even when the concentration of mud in the classification tank becomes high, water can be supplied by operating this make-up water valve, so that gravel can be classified with clean water having low mud concentration and settled. Since the jet bubble flow penetrates the gravel layer that is sinking down the road, the gravel is washed by the energy of the bubbles, so that high-quality gravel can be obtained.

The method and apparatus for removing light substances mixed in gravel according to the present invention having such excellent effects are of great industrial value.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view schematically showing one embodiment of a device of the present invention suitable for carrying out a method of the present invention.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 2;

FIG. 4 is a sectional view corresponding to FIG. 3, showing another embodiment of the device of the present invention.

FIG. 5 is a cross-sectional view corresponding to FIG. 2, showing still another embodiment of the device of the present invention.

FIG. 6 is a front view showing an example of the orifice pipe when the orifice pipe is used as a bubble flow generator.

FIG. 7 is a sectional view taken along line CC in FIG. 6;

[Explanation of symbols]

 1 Classification tank 2 Sedimentation path 2a Compartment plate 3 Bubble generator 3a Orifice pipe 3aa Orifice 3b Compressor 3c Flow control valve 3d Pressure control valve 3e Check valve 4 Bubble path 5 Overflow weir 6 Partition plate 7 Gravel outlet opening 8 Gravel Feeding device 8a Feeder 8b Gravel loading conveyor 8c Separator 9 Flood water gutter 10 Flood water circulation mechanism 10a Foreign matter removal sieve 10b Circulating water tank 10c Circulation pump 11 Gravel discharging conveyor 12 Makeup water valve 13 Gravel 14 Aggregate 15 Light substances

Claims (12)

[Claims] 1. A curtain having a constant layer thickness in the water in a classification tank provided with an overflow weir at the top thereof, and water constantly flowing from the overflow weir to gravel mixed with light substances. The sediment is settled, and a jet bubble flow is sent through the gravel layer at a predetermined angle within a range of 45 to 135 degrees with respect to the settling direction, so that light substances mixed in the gravel being settled together with the bubbles and the gravel layer After the water is driven out, the light substance is raised by the buoyancy of the air bubbles and the upward flow of water generated in the classification tank and overflows from the overflow weir together with the water. A method for removing light substances mixed in gravel, wherein particles are dropped below a classification tank to obtain gravel from which light substances have been removed. 2. The gravel that has fallen below the classification tank when the gravel from which light substances have been removed is carried out from the water is carried out by a gravel carrying conveyor facing the gravel exit opening. A method for removing light substances mixed in gravel as described. 3. The gravel according to claim 1, wherein the water overflowed from the overflow weir is used as circulating water for supplying into a classification tank after removing light substances contained therein. For removing light substances mixed into ash. 4. A light substance settled in a curtain form.
A sedimentary channel (2) of gravel (13) mixed with (15) is formed, and the gravel (13) mixed with the light substance (15) of the sedimentary channel (2) is settled down in a curtain shape. The sedimentation channel (2) spans the entire width of the gravel (13) that is settled on one side across the
A bubble flow generator (3) for generating a jet bubble flow penetrating the gravel layer at a predetermined angle within a range of 45 to 135 degrees with respect to the sedimentation direction of the gravel layer is installed, and a sedimentation path is provided.
On the other side of the gravel layer that allows the sedimentation of (2) to be settled, a bubble path (4) is formed on the other side in which bubbles from the jet bubble flow rise, and water overflows constantly at the top. A classification tank (1) having a weir (5) and a gravel exit opening (7) formed at the bottom of the sedimentation channel (2);
Gravel loading device (8) for putting the gravel (13) mixed with light substances (15) into the classification tank (1) in the form of a curtain with a certain layer thickness above the sedimentation path (2) of (1) And an overflow gutter (9) for draining water overflowing from the overflow weir (5) of the classification tank (1).
A light substance mixed into the gravel, comprising: a gravel carry-out conveyor (11) installed directly below a gravel outlet opening (7) of the classification tank (1). Removal equipment. 5. A sedimentation path (2) is formed in a classification tank (1), and each of the sedimentation paths (2) has a bubble flow generator.
5. The apparatus for removing light substances mixed in gravel according to claim 4, wherein the apparatus is provided with (3), a bubble path (4) and an overflow weir (5). 6. The gravel according to claim 5, wherein the gravel outlet opening (7) at the bottom of the sedimentation channel (2, 2) formed in the classification tank (1) is shared. Light substance removal equipment. 7. A bubbling flow generator (3) is arranged parallel to and horizontal to a gravel layer in which an orifice pipe (3a) having a number of orifices (3aa) formed at predetermined intervals in a longitudinal direction thereof is settled. The orifice pipe (3a) is provided with a check valve (3e) and at least a flow control valve.
The apparatus for removing light substances mixed in gravel according to any one of claims 4 to 6, wherein the apparatus comprises (3c). 8. The air bubble generating device (3) according to claim 7, wherein a plurality of orifice tubes (3a) are installed at intervals in the sedimentation direction of the gravel layer submerging the sedimentation passage (2). For removing light substances mixed in gravel. 9. A settling path (2) as a bubble flow generating device (3).
The orifice pipe (3a) according to claim 7 or 8, wherein an orifice pipe (3a) formed so that an orifice (3aa) adjacent in the longitudinal direction of the gravel layer sinking the air ejects bubbles at different angles. A device for removing light substances mixed in gravel. 10. A foreign matter removing sieve (10a) for removing light substances (15) contained in overflow water drained from an overflow water gutter (9).
Is provided, and the light substance is removed by the foreign matter removing sieve (10a).
The light mixed with gravel according to any one of claims 4 to 9, further comprising an overflow water circulation mechanism (10) for supplying the overflow water from which the (15) has been removed to the classification tank (1). Material removal device. 11. To prevent the gravel (13) mixed with the light substance (15) supplied from the gravel charging device (8) from immediately flowing into the overflow weir (5) from the upper part of the bubble channel (4). Partition board (6)
The apparatus for removing light substances mixed in gravel according to any one of claims 4 to 10, wherein the apparatus is provided at a position defining the thickness of the gravel layer above the classification tank (1). 12. A circulating water tank (10b) of the overflow water circulating mechanism (10).
The apparatus for removing light substances mixed in gravel according to claim 10 or 11, further comprising a make-up water valve (12) for supplying water to the sand.