JPH05305271A - Crushed sand dust removing device - Google Patents

Abstract

PURPOSE:To provide a crushed sand dust removing device capable of removing dust (fine powder) contained in crushed sand easily and to a required grain size with other advantages such as low initial cost, low running cost and easy operation. CONSTITUTION:The subject crushed sand dust removing device consists of a charging pipe 230 for crushed sand dust/particles provided in the upper center of a single barrel cylindrical casing 210, a conical device 240 and an inverted conical coarse particle guide cone 220 of perforated plate, expanded metal or metal netting fixed below the charging pipe 230 to a casing 210, and an air inflow pipe 260 arranged at the bottom of the casing 210. In addition, an air discharge pipe 270 is provided at the top of the casing 210, and a cyclone 300, an air control valve 410 and a suction fan 400 are connected to the air discharge pipe 270.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crushed sand dust removing device used to remove fine particles (dust) in crushed sand produced by a crusher used in a crushing sand plant.

[0002]

2. Description of the Related Art In recent years, due to depletion of natural sand (river sand, mountain sand, land gravel, sea sand), the amount of crushed sand in the crushed stone industry has been increasing year by year, and the demand is strong in the future. .. In the crushed stone production method, there has been a crushing sand plant that uses a crusher for cutting the mined rock into small pieces, and in the crushing work using the crusher, it is inevitably necessary to generate fine powder smaller than a desired size. FIG. 3 shows a flow sheet of a conventional sand crushing plant, in which the raw material in the raw material bottle 10 is cut out by a vibrating feeder 20 and then crushed by a corn crusher 30.
Is crushed by, and is sieved by a vibrating sieve 40, and the oversize having a desired particle size or more is recycled to the cone crusher 30 again. The undersized crushed sand is sent to the air separator 50, and is classified into crushed sand and fine particles (dust) smaller than the crushed sand by classification. Qf, Qc, Qr, Qp, Qd, Qs in the figure
Indicates the amount produced per hour.

On the other hand, FIG. 4 shows a particle size distribution curve diagram in each step of the flow sheet of FIG. 3, in which the material particle size is crushed and the undersize after sieving is. This crushed sand contains about 5-10% of dust, and as a result of classification, the final product is obtained (is the particle size distribution of dust), but it falls within the range of the two dotted lines which is the JIS crushed sand standard. Therefore, the crushed sand satisfies the standard. See J
The IS standard stipulates that the amount of dust contained in aggregate of 74 μm or less should be 7% or less of the total amount, and dust contamination adversely affects the quality, so it must be eliminated as much as possible.

The dust contained in the crushed sand in the crushed sand plant is about 400 μm or less, and a startate type air separator 100 is used as the air separator 50 for removing the dust from the crushed sand. FIG. 5 is a vertical cross-sectional view of the startate type air separator 100, in which a dispersion plate c is provided on a vertical rotation axis n that is rotationally driven by a variable speed electric motor M on the central axis of a can body composed of an outer casing i and an inner casing f. , The main blade e and the auxiliary blade d are fixed and rotate. The raw material introduced into the dispersion plate c from the raw material supply port a through the chute b is given a centrifugal force by the dispersion plate c, and is discharged radially toward the inner casing f in a radial direction evenly around the circumference. The circulating swirling airflow generated by the rotation of e becomes an ascending swirling airflow in the inner casing f and carries fine powder among the dispersed raw material powder particles upward and passes through the auxiliary blade d. At this time, the granular material is subjected to centrifugal force and inertial force by the auxiliary blade d, separated into coarse particles and fine particles, and only the fine particles are sucked into the main blade e,
The coarse particles having a large inertial force collide with the inner surface of the inner casing f, settle along the wall surface, and are discharged from the coarse particle discharge port I. on the other hand,
The fine powder sucked into the main blade e is the inner casing f
It is carried into the annular space m between the outer casing i and the outer casing i, is given a centrifugal force by the annular downward swirling airflow, is spirally conveyed downward along the inner wall surface of the outer casing i, and is discharged from the lower fine powder outlet K by gravity. To be done. Annular space m in the figure
The annular swirling airflow that has passed through is sucked inward from the guide vanes J provided in the intermediate portion of the inner casing f and becomes the swirl rising airflow, and repeats the separating action while circulating. The number of rotations of the rotation axis n is set by the specific gravity of the granular material, the shape of the fine particles and the classification point (Cut Point), and the number of the prosthetic ribs d also contributes to the setting of the classification point by design, but the classification point is delicate. Such adjustment is controlled by adjusting a horizontally expandable valve plate g provided between the main blade e and the auxiliary blade d. P and Q are air inlets and outlets for heat exchange.

Thus, the main blade e is used for adjusting the air volume, and the air volume increases as the number of blades of the main blade e increases. Further, although the air volume also increases by increasing the number of rotations of the rotating shaft n, the classification point is also changed at the same time. The auxiliary blade d is used for adjusting the fineness (classification point), and becomes finer when the number of blades is increased. The valve plate g has a handle h
It is also used to adjust the fineness by operating, and it is effective for fine adjustment, and if the opening is made small (protruding inward much), the classification point becomes fine.

[0006]

Dust removal of crushed sand in the crushing stone industry has a relatively short history, and there is currently no definitive classifier for dryly removing fine particles (dust) in crushed sand. Therefore, as described above, existing high-class classifiers such as the startate type air separator are used, but the initial cost is higher than the purpose, the power consumption is large, and the classification operation is relatively difficult. There was a need for the advent of a crushed sand dust removal device suitable for dust disposal, which has drawbacks, low classification accuracy, low power consumption, and low initial cost. In addition, the wet method of cleaning the dust contained in the crushed sand with water results in a crushed sand plant that additionally includes the steps of cleaning, drying, and wastewater treatment, which has the drawback of increasing the initial cost and running cost and increasing the production cost. there were.

[0007]

In order to solve the problems described above, in the crushed sand dust removing apparatus of the present invention, a crushed sand powder or granular material is supplied to the center of the upper end of a single-body cylindrical casing. In addition to providing a charging pipe, a conical body that disperses the charged powder particles around the charging pipe is arranged under the charging pipe, and a conical rough shape consisting of a perforated plate, expanded metal or wire mesh is provided below the conical body. A grain guide cone is fixed to the casing, an air inflow pipe is provided at the lower part of the casing, an exhaust pipe is provided at the upper part of the casing, and a cyclone for collecting dust in dust-containing gas, an air flow control valve, and a suction fan are provided. It was connected downstream of the exhaust pipe.

[0008]

Since the present invention is constituted as described above, the crushed sand powder particles of the raw material supplied from the charging pipe into the casing come into contact with the conical body and are scattered in four directions and fall to the coarse-grained guide cone. Move down along the slope. At that time, the air introduced into the casing from the air inflow pipe becomes an updraft due to the suction force of the suction fan, passes through the coarse-grain guide cone, and goes to the exhaust pipe. Associated with it becomes dust-containing gas and enters the cyclone, where dust is collected. The adjustment of the classification points of coarse particles and dust is adjusted by the flow rate of the ascending airflow flowing in the casing, and its operation is controlled by opening and closing the air volume adjustment valve in front of the suction fan.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an overall vertical sectional view of a crushed sand dust removing apparatus according to an embodiment of the present invention, and FIG. 2 is an overall vertical sectional view of a crushed sand dust removing apparatus according to another embodiment of the present invention. Figure 1
In the above, the crushed sand dust removing device 200 is composed of a casing 210 having a single barrel shape, a cyclone 300 connected to the casing 210, an air flow control valve 410, and a suction fan 400. The casing 210 is provided with a charging pipe 230 at the center of its upper end.
A cone-shaped conical body 240 is arranged immediately below the cone-shaped conical body 240, and an inverse cone-shaped coarse-grained guide cone 220 is fixed to the inner surface of the casing 210 below the periphery of the conical body 240. Coarse-grained guide cones are made by forming perforated steel plates, expanded metal and wire mesh. The size of the through holes of the perforated plate is set to be 5 to 10 times the size of the dust particles in consideration of the size of the dust particles to be removed. The center of the coarse-grain guide cone 220 has a coarse-grain discharge pipe 2
50 are connected. An air inflow pipe 260 is provided at a lower side of the casing 210, and an exhaust pipe 270 is provided at an upper end of the casing 210 diagonally opposite to the air inflow pipe 260.
The subsequent cyclone 300, the air flow control valve 410, and the suction fan 400 are connected, and the suction fan 400 and the air inflow pipe 2 are connected.
A circulation path 500 is provided between the circulation path 500 and 60.

FIG. 2 shows a crushed sand dust removing apparatus according to another embodiment of the present invention. Explaining only the points different from FIG. 1, the first coarse particles are located below the lower end of the conical body 240 inside the casing 210. The guide cone 220a is extended and provided,
Next, an air inflow pipe 260 is provided by fixing the second coarse grain guide cone 220b in the shape of an inverted cone to the inner surface of the casing 210 and surrounding the coarse grain discharge pipe 250 connected to the lower center of the coarse grain guide cone 220b. The vertical casing is provided with a lower casing 210a having substantially the same shape as the coarse-grain guide cone 220b, and the exhaust pipe 270 is also provided so as to surround the input pipe 230.
It is intended that the rising of air is performed symmetrically with respect to the central axis as compared with the above-mentioned one.

The operation of the crushed sand dust removing device of the present invention constructed as above will be described. Suction fan 400
When crushed sand powder particles are supplied from the charging pipe 230 in a state in which the ascending air current is formed in the casing 210 by driving, the particles collide with the conical body 240 and are dispersed in four directions, and each particle is coarse-grained guide cone 220 (or 220a). And 220b) and moves on the slope. At this time, the fine powder (dust) in the granular material rides in the rising air flow blown up from the through hole of the coarse-grain guide cone 220 on the slope and is discharged from the exhaust pipe 270 as dust-containing gas, and the coarse particles fall on the slope as they are. Coarse grain discharge pipe 25
It is taken out from the casing 210 from 0. Exhaust pipe 270
The dust-containing gas that has come out enters the cyclone 300 where dust is collected, and the cleaned air comes out from the exhaust pipe 300c and passes through the air volume control valve 410 and the suction fan 400 and again into the casing 210 from the air inflow pipe 260. Enter and circulate. Three
00a is an inlet pipe of the cyclone 300, and 300b is a fine powder discharge pipe. The adjustment of the classification points of the coarse particles and the fine particles (dust) is controlled by the air volume of the ascending airflow flowing in the casing, and is adjusted by adjusting the opening degree of the air volume control valve 410 in front of the suction fan 400.

The apparatus for removing crushed sand dust of the present invention has no moving parts other than the formation of an air flow in the casing by a suction fan, has a simple structure, is easy to assemble, inspect, disassemble, and repair, and classifies dust to be removed. It is easy to change points and easy to handle. Also, since the air flow is one-way in the casing and there is no internal circulation, the pressure loss in the device is small and the fan power cost is small.

[0013]

The crushed sand dust removing device of the present invention is not only simple in structure and inexpensive in initial cost, but also has low power cost and easily removes dust contained in the crushed sand produced to a required particle size. be able to. Therefore, high-quality crushed sand with less dust can be manufactured at low cost, and the device can be easily assembled, inspected, and disassembled, so that the maintainability is excellent.

[Brief description of drawings]

FIG. 1 is an overall vertical cross-sectional view of a crushed sand dust removing device according to an embodiment of the present invention.

FIG. 2 is an overall vertical sectional view of a crushed sand dust removing device according to another embodiment of the present invention.

FIG. 3 is a flow sheet of a conventional crushing sand plant.

FIG. 4 is a particle size distribution curve diagram in each step of the crushed sand plant.

FIG. 5 is an overall longitudinal sectional view of a conventional startate type air separator.

[Explanation of symbols]

 10 Raw material bottle 20 Vibratory feeder 30 Cone crusher 40 Vibrating sieve 50 Separator 100 Startevanto type air separator 200 Crushed sand dust remover 210 Casing 210a Lower casing 220 Coarse grain guide cone 220a Coarse grain guide cone 220b Coarse grain guide cone 230 Input pipe 240 Cone 250 Coarse grain discharge pipe 260 Air inflow pipe 270 Exhaust pipe 300 Cyclone 300a Inlet pipe 300b Fine powder discharge pipe 300c Exhaust pipe 400 Suction fan 410 Air volume control valve 500 Circulation path a Raw material supply port b Chute c Dispersion plate d Auxiliary blade e Main blade f Inner casing g Valve plate h Handle i Outer casing m Annular space n Rotation axis I Coarse grain discharge port J Guide vane K Fine powder outlet M Variable speed motor P Cold air inlet Q Air outlet

Claims (1)

[Claims] 1. A charging pipe for supplying crushed sand powder and granules is provided at the center of the upper end of a single-body cylindrical casing, and a cone is arranged below the charging pipe to disperse the powder and granules into the surroundings. Installed below the cone, a reverse cone-shaped coarse-grained guide cone made of a perforated plate, expanded metal or wire mesh is fixed to the casing, an air inflow pipe is provided at the lower part of the casing, and an exhaust gas is provided at the upper part of the casing. A crushed sand dust removing device in which a pipe is provided and a cyclone for collecting dust in dust-containing gas, an air flow control valve, and a suction fan are connected downstream of the exhaust pipe.