JP6475389B2 - Wet classification method - Google Patents

Description

  The present invention relates to a wet classification method.

  When classifying relatively small soil particles containing clay, silt, etc., in order to suppress the diffusion of the soil particles in the air, the soil particles are mixed with the liquid and the soil particles are classified in the liquid. Yes. As a wet classification method used in such liquid classification (wet classification), a liquid containing soil particles is placed in a classification water tank, and the soil particles in the liquid are sieved into fine small-sized and coarse large-sized soil particles. Those that sort out are known.

  In such a wet classification method, the soil particles receive a force in the direction of passing through the sieve due to gravity, centrifugal force, etc., while the small-diameter sort passes through the sieve, while the large-diameter soil particles accumulate on the surface of the sieve. There is a risk of clogging. Therefore, it is possible to reduce the concentration of soil particles in the classification tank, install the screen obliquely with respect to the passing direction of the small-diameter soil particles, or enlarge the surface area of the sieve to increase the size of the large-diameter soil particles deposited per unit area. The clogging of the sieve is suppressed by reducing the capacity.

  However, the wet classification method for reducing the concentration of soil particles has a problem that the classification efficiency is remarkably lowered because the amount of soil particles that can be classified at a time becomes small.

  Further, in the wet classification method using a large surface area sieve, there is a problem that the size of the soil particles becomes large.

  Therefore, technical problems to be solved to realize a wet classification method that can be efficiently performed in liquid and can be applied in a space-saving manner arise, and the present invention solves this problem. With the goal.

The present invention has been proposed to achieve the above object, and the invention according to claim 1 is characterized in that a liquid containing soil particles is accommodated in a classification water tank, and the soil particles are larger in diameter than the classification boundary particle size. A wet classification method for selecting soil particles and small-diameter soil particles less than the classification boundary particle size, and vibrating the mesh basket provided in the classification water tank with a vibrating body, the small-diameter soil particles in the classification water tank Provided is a wet classification method in which suction is performed by a suction means provided in the mesh cage, the mesh cage is allowed to pass, and the mesh basket is discharged out of the classification tank.

  According to this configuration, the suction means sucks small-diameter soil particles from the outside to the inside of the mesh cage, and the vibrating body attracts large-diameter soil particles that tend to adhere to the surface of the mesh cage by the suction force of the suction means. Therefore, the clogging of the mesh cage caused by the accumulation of the large-diameter soil particles on the surface of the mesh cage can be suppressed, and classification in water can be performed efficiently. The “classified boundary particle size” is a lower limit value of the particle size of the large-sized soil particles to be left in the classified water tank.

  In addition, small-diameter soil particles can pass through the mesh cage without increasing the size of the equipment by allowing small-diameter soil particles to pass through the side and bottom of the mesh cage formed in a bottomed column shape and then into the mesh cage. An area can be secured.

  According to a second aspect of the present invention, in the first aspect of the present invention, the suction force of the suction means is set so that the large-diameter soil particles adsorbed on the surface of the mesh cage settle in the classification water tank by gravity. A wet classification method is provided.

  According to this configuration, the suction force of the suction means, that is, the force generated by the water flow generated by the suction means, is the sum of the buoyancy acting on the large-diameter soil particles and the frictional force according to the suction force is less than gravity. Therefore, large-sized soil particles that tend to be attracted by the suction means and adhere to the surface of the mesh basket are likely to settle due to gravity, thus further suppressing clogging of the mesh basket and classification in water Can be implemented efficiently.

  Invention of Claim 3 provides the wet classification method which produces the stirring water flow which goes to the said mesh cage in the said classification water tank in the invention of Claim 1 or 2.

  According to this structure, since the stirring water flow of the stirrer stirs the soil particles in the classification water tank, the small-diameter soil particles can easily pass through the mesh basket, and thus the classification in the liquid can be performed efficiently. it can.

  The invention according to claim 4 is the wet classification according to claim 3, wherein the stirring water flow is set so as to separate large-diameter soil particles adsorbed on the surface of the mesh cage from the surface of the mesh cage. Provide a method.

  According to this configuration, the clogging of the mesh basket is further suppressed by separating the large-diameter soil particles that tend to adhere to the surface of the mesh basket, so that the classification in the liquid can be performed more efficiently. Can be implemented.

  A fifth aspect of the present invention provides the wet classification method according to any one of the first to fourth aspects of the present invention, wherein the mesh basket is attached to the classification water tank via a vibration isolating means.

  According to this configuration, since the vibration isolating means suppresses the vibration of the mesh basket being transmitted to the classification water tank and the peripheral equipment, the separation distance to be secured between the wet classifier and the peripheral equipment is reduced. A wet classifier can be installed in a space-saving manner.

  The present invention can efficiently perform classification in a liquid and can perform wet classification in a space-saving manner.

The schematic diagram which shows one Example of the wet classification apparatus which concerns on this invention. It is a figure which shows a selection means, (a) is a side view, (b) is a top view which shows the selection means of the state which removed the vibration body, (c) is a selection means of the state which attached the vibration body. FIG. It is a figure which shows a mesh cage | basket, (a) is a side view, (b) is a top view. It is a figure which shows a vibrating body, (a) is a side view, (b) is a top view. It is a figure which shows a suction means, (a) is a side view, (b) is a top view. The schematic diagram which shows the force by the buoyancy, gravity, frictional force, and water flow which act on a soil particle.

  The wet classification method according to the present invention efficiently performs classification in a liquid, and achieves the purpose of realizing a wet classification method that can be applied in a space-saving manner, in order to achieve the purpose of realizing a wet classification method in a classification water tank. A wet classification method of sorting the soil particles into large-sized soil particles having a classification boundary particle size or larger and small-sized soil particles having a particle size smaller than the classification boundary particle size, the mesh basket provided in the classification water tank This was realized by sucking the small-diameter soil particles in the classification water tank with a suction means, passing through the mesh basket, and discharging it out of the classification water tank while vibrating with a vibrating body.

  Hereinafter, a wet classifier 1 according to an embodiment of the present invention will be described with reference to the drawings. In the following, the terms “upper” and “lower” correspond to the upper and lower parts in the vertical direction.

  As shown in FIG. 1, the wet classifier 1 includes a classified water tank 10 and a sorting means 20.

  The wet classifier 1 hydrates the soil particles, sorts them into small-sized and large-sized soil particles in the classified water tank 10, removes the small-sized soil particles from the classified water tank 10, and converts the large-sized soil particles into the classified water tank 10. It will be left behind.

  The soil particles classified by the wet classifier 1 are relatively small particles that are difficult to classify in the air, for example, soil containing clay or silt adsorbed with radioactive substances. Further, in this example, the small-diameter soil particles are exemplified below as small-diameter soil particles having a large specific surface area, and the large-diameter soil particles are exemplified by large-diameter soil particles having a small specific surface area. The particles, small-diameter soil particles, and large-diameter soil particles are not limited to these.

  The classification water tank 10 stores mud water formed by adding water to soil as soil particles. Moreover, the large-diameter soil particles deposited on the bottom of the classification water tank 10 after classification are discharged to the outside.

  The selection means 20 includes a mesh cage 21 having a mesh size corresponding to the classification boundary particle size, a vibrating body 22 that vibrates the mesh cage 21, and a pumping pump 23 as a suction means that sucks mud water to generate the suction water flow f1. And. Here, the “classified boundary particle size” is a lower limit value of the particle size of the large-sized soil particles to be left in the classified water tank 10.

  In addition, the wet classifier 1 includes a stirrer 30 disposed below the mesh basket 21 in the classification water tank 10. The stirrer 30 generates the stirring water flow f <b> 2 by the rotation of the fan 31, and stirs the muddy water in the classification water tank 10. The stirring water flow f2 is formed so as to flow in order from the lower center of the classification water tank 10 to the upper center, the upper side, and the lower side. The stirring water flow f2 peels off the soil particles adhering to the surface of the mesh basket 21. Further, the stirring water flow f2 can easily collect foreign matters by causing relatively large foreign matters such as fallen leaves and branches contained in the muddy water to float on the water surface. In addition, the arrangement position of the stirrer 30 is not limited to the lower side of the mesh basket 21 and may be any place as long as the muddy water in the classification water tank 10 can be circulated.

  Next, the sorting unit 20 will be described with reference to FIGS.

  The mesh cage 21 is formed in a bottomed cylindrical shape. The mesh car 21 is provided with an opening 21a on the upper side, and the pump 23 is accommodated in the mesh car 21 through the opening 21a. The mesh cage 21 may have any shape as long as it can secure a passage area through which small-diameter soil particles can efficiently pass, and may be, for example, a quadrangular prism.

  The vibrating body 22 transmits a rotational movement of a motor (not shown) to the vibrating body 22 and vibrates horizontally, vertically, or diagonally. The vibrating body 22 is placed on a disk-shaped base portion 22a.

  The base 22 a is connected to the upper part of the mesh car 21 and is attached to the mesh car 21 integrally. Thereby, the vibrating body 22 and the mesh basket 21 vibrate together. In addition, four inverted U-shaped flanges 22b that connect the base 22a and the classification water tank 10 are provided on the periphery of the base 22a. An anti-vibration rubber 24 as an anti-vibration means is interposed between the classification water tank 10 and the flange 22b. The vibration isolating means is not limited to the vibration isolating rubber 24, and any means may be used as long as it suppresses the vibration of the mesh basket 21 from being transmitted to the classification water tank 10 and peripheral devices. It does not matter. Thus, the vibration isolation rubber 24 absorbs the vibration of the mesh cage 21 and suppresses the vibration from being transmitted to the classification water tank 10 and the peripheral equipment, so that the separation distance to be secured between the wet classifier 1 and the peripheral equipment Is reduced.

  The pumping pump 23 discharges the muddy water in the classification water tank 10 to the outside. The pumping pump 23 is fixed to a frame 23 a that is independent from the mesh cage 21. The frame 23a is connected to the wet classifier 1 in a state where the pump 23 is accommodated in the mesh basket 21, so that the pump 23 is positioned at a predetermined position in the mesh basket 21. Yes. The muddy water containing small-diameter soil particles discharged to the outside is bagged after being dehydrated.

  Next, the operation of the wet classifier 1 will be described with reference to FIG.

  The large-diameter soil particles are present on the surface of the mesh cage 21 without passing through the mesh of the mesh cage 21. At this time, a pressing force F, gravity Fg, and buoyancy Fb directed to the mesh cage 21 are acted on the large-diameter soil particles by the water flow f1 generated by the suction force of the pumping pump 23.

The pressing force F by the water flow f1 is as shown in Formula 1 from Stokes' law.

Further, the gravity Fg is as shown in Formula 2.

The buoyancy Fb is as shown in Equation 3.

When the soil particles do not adhere to the surface of the mesh basket 21, the pressing force F generated by the water flow f1 is smaller than the resultant force of the gravity Fg and the buoyancy Fb, and therefore Equation 4 is established.

Here, when Expressions 1 to 3 are substituted into Expression 4, Expression 5 is established.

In Formula 5, the viscosity η of the fluid is 0.01 [g / cm · s], the density ρg of the soil particles is 2.6 [g / cm3], the density ρf of the fluid is 1.0 [g / cm3], gravity When the acceleration g is 980.7 [cm / s2] and the friction coefficient μ is 0.5, the flow velocity v of the water flow according to the radius r of the soil particles is as shown in Table 1.

The flow velocity v ′ of the water flow passing through the mesh cage 21 according to the suction force of the pumping pump 23 is as shown in Equation 6.

  Here, the pumping amount Q of the pump 23 is 50 [m3 / h], the effective surface area of the mesh car 21, that is, the surface area of the mesh car 21 (2.0 [m2]) and the passing rate of the mesh car 21 (40 If the product of [%]) is 0.8 [m2], the flow velocity v ′ of the water flow passing through the mesh cage 21 corresponding to the suction force of the pump 23 is 1.04 [m / min].

  That is, in the wet classifier 1, the gravity acting on the soil particles having a particle size of 0.10 [mm] or more becomes larger than the resultant force of the buoyancy Fb and the frictional force according to the pressing force F by the water flow f1, so the particle size It can suppress that 0.10 [mm] or more of soil particles accumulate on the surface of the mesh basket 21 and become clogged.

  Further, since the vibrating body 22 vibrates the mesh cage 21, the frictional force acting between the surface of the mesh cage 21 and the soil particles is further reduced, so that the mesh cage 21 can be further prevented from being clogged. .

  In this way, in the wet classifier 1 according to the present invention, the pumping pump 23 sucks small-diameter soil particles from the outside to the inside of the mesh cage 21, and the vibrator 22 adheres to the surface of the mesh cage 21. By separating the large-sized soil particles from the surface of the mesh cage 21, clogging of the mesh cage 21 is suppressed, so that classification in the liquid can be performed efficiently.

  Further, since the small-diameter soil particles can pass into the mesh cage 21 through the side and bottom surfaces of the mesh cage 21 formed in a bottomed column shape, the small-diameter soil in the mesh cage 21 is not increased in size. The passage area of particles can be secured.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

DESCRIPTION OF SYMBOLS 1 ... Wet classification apparatus 10 ... Classification water tank 20 ... Sorting means 21 ... Mesh basket 22 ... Vibrating body 22a ... Base 22b ... Flange 23 ... Pumping pump 23a ...・ Frame 24 ... Antivibration rubber 30 ... Stirrer 31 ... Fan

Claims (5)

A wet classification method in which a liquid containing soil particles is contained in a classification water tank, and the soil particles are sorted into large-diameter soil particles having a classification boundary particle size or larger and small-diameter soil particles having a particle size smaller than the classification boundary particle size.
While the mesh basket provided in the classification tank is vibrated by a vibrating body, the small-diameter soil particles in the classification tank are sucked by the suction means provided in the mesh basket and are passed through the mesh basket. A wet classification method characterized by discharging to the outside.   2. The wet classification method according to claim 1, wherein the suction force of the suction means is set so that large-diameter soil particles adsorbed on the surface of the mesh cage settle in the classification water tank by gravity.   The wet classification method according to claim 1 or 2, wherein a stirring water flow toward the mesh basket is generated in the classification water tank.   4. The wet classification method according to claim 3, wherein the stirring water flow is set so that large-diameter soil particles adsorbed on the surface of the mesh cage are separated from the surface of the mesh cage.   The wet classification method according to any one of claims 1 to 4, wherein the mesh cage is attached to the classification water tank via a vibration isolating means.