JPH05285455A - Ground sand dust removing apparatus - Google Patents

Abstract

PURPOSE:To provide a ground sand dust removing apparatus capable of easily and arbitrarily removing the dust (fine powder) in ground sand, low in both of initial cost and running cost and easy to operate. CONSTITUTION:A dispersing plate 250 is arranged to the cylindrical center shaft of a casing 210 consisting of a cylindrical pipe 210a and a conical part 210b and a charging pipe 270 supplying ground sand is provided above the dispersing plate 250 and rotary blades 280 each composed of a vertical flat plate are fixed to the dispersing plate 250 through a support 260 at the upper part of the cylindrical pipe 210a. A plurality of valve plates 290 each composed of a freely advancing and retreating horizontal flat plate are arranged directly under the rotary blades 280 and a revolving air stream discharge pipe 292 and a dust collecting cyclone 300 are connected to the casing 210 and an air inflow pipe 282 is provided to the lower part of the casing 210.

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. 5 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 is then crushed by a cone 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. 6 shows a particle size distribution curve diagram in each step of the flow sheet of FIG. 5, 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. 7 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 which 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 middle portion of the inner casing f and becomes the swirl rising airflow, and repeats the separating action while circulating. The rotation speed of the rotary shaft n is set by the specific gravity of the powder or granules, the shape of the particles and the classification point (Cut Point), and the number of auxiliary blades d in the design also contributes to the setting of the classification point. The main blade e
It is controlled by adjusting a horizontally expandable valve plate g provided between the auxiliary blade d 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. FIG. 8 is an explanatory view showing the flow of powder and air in the startate type air separator 100, and FIG. 9 is a perspective view of the startate type air separator 100.

[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 above-mentioned problems, in the crushed sand dust removing device of the present invention, a horizontal pipe which is rotatable around a vertical axis and a charging pipe for supplying powdered particles of crushed sand. A single-body and tubular casing having a dispersion plate made of a plate, a rotor blade for generating a swirling upward airflow, and a valve plate made of a horizontal flat plate disposed directly below the rotor blade and capable of moving back and forth in the horizontal direction. The casing is provided with a discharge pipe through which the swirl upward airflow of the casing is discharged in a cutting line direction, a cyclone for collecting dust is connected to the discharge pipe, and an air intake port is provided at a lower portion of the casing. Is provided.

[0008]

Since the present invention is configured as described above, the powder and granules supplied from the raw material feeding pipe onto the dispersion plate are subjected to centrifugal force by the rotating dispersion plate so that they are substantially evenly circumferentially aligned in the horizontal direction. The swirling ascending airflow that is radiated to the air and introduced from the air inlet and flows in the casing due to the rotation of the rotor blades is subjected to classification due to the difference between the upward drag force exerted by the air flow and gravity, and the coarse particles overcome the drag force. It falls by its own weight and is discharged from the coarse-grain discharge port along the inner wall surface of the casing. In addition, the fine powder in the raw material rides on this rising air flow and goes to the cyclone from the casing outlet along with the swirling air flow.
At this time, the coarse particles in the fine powder are eliminated due to the secondary classification effect due to the protruding length of the valve plate below the rotor blades.
Head to the coarse grain outlet. The dust contained in the dust-containing gas thus exiting the casing is collected by the cyclone.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 4 show an embodiment of the present invention,
1 is an overall vertical cross-sectional view of the crushed sand dust removing device, FIG. 2 is a plan view of the crushed sand dust removing device, FIG. 3 is a vertical cross-sectional view of a main part of the crushed sand dust removing device, and FIG. It is a perspective view.
In the figure, the crushed sand dust removing device 200 is shown as a cylindrical pipe 21.
0a and a conical tube 210b connected to the variable speed electric motor 220 on the upper central axis of the casing 210.
Also, a dispersion plate 250 formed of a horizontal disk is attached to the lower end of a rotary shaft 240 that rotates via a speed reducer 230, and a raw material supply pipe 270 having a charging port 270a for charging a raw material onto the dispersion plate 250 is provided with a raw material supply pipe 270. A cylindrical pipe 210a of the casing 210 is provided on the periphery, and the upper part of the cylindrical pipe 210a is made larger to a size larger than that of the rotary pipe. It is solidified and placed. Further, a plurality of valve plates 290 each having a protruding plate 290a formed of a horizontal flat plate that can be moved back and forth are disposed inside the casing 210 (cylindrical tube 210a) immediately below the rotary blade 280. As the means for moving the valve plate 290 back and forth, in addition to manual operation, power means such as an air cylinder, a hydraulic cylinder or an electric motor can be used.

The casing 210 facing the rotor 280
An opening is provided at one circumference of the (cylindrical tube 210a), and as shown in FIG. 2, the swirling airflow flowing by the rotation of the rotor 280 is tangentially discharged from the cylindrical tube 210a and guided to the cyclone 300 installed downstream. A connecting pipe 292 is provided. As the cyclone 300, a cut-line inflow type cyclone or a spiral cyclone that is normally used is used. A circulation pipe 310 is connected between the exhaust port 300a of the cyclone 300 and the air inflow pipe 282 provided in the lower portion of the conical pipe 210b. The air inflow pipe 282 is provided orthogonally to the casing 210 toward the center of the casing 210. However, as shown in FIGS. It is preferable to attach tangentially to (the same). In the illustrated embodiment, the round pipe 282 is connected to the square duct 280a attached to the casing 210, and the circulation pipe 310 is a circular pipe. In this embodiment, the circulation pipe 310 is provided between the exhaust port 300a of the cyclone 300 and the air inflow pipe 282 to circulate the air.
A method may be adopted in which clean air after dust collection of 0 is directly discharged to the atmosphere and the atmosphere is introduced into the casing 210.

The operation of the crushed sand dust removing device of the present invention constructed as above will be described. Variable speed electric motor 22
By driving 0, the rotary shaft 240, the dispersion plate 250, and the rotary blade 280 rotate integrally via the speed reducer 230. The powder particles (crushed sand) of the raw material supplied from the input port 270a of the raw material input pipe 270 are subjected to centrifugal force by the dispersion plate 250 and are radiated from the dispersion plate 250 to the surrounding space substantially horizontally in a spiral shape. On the other hand, in the casing 210, the air introduced from the air inflow pipe 282 forms a swirling upward airflow due to the rotation of the rotary blades 280, and the powdery particles discharged around the dispersion plate 250 by this airflow perform a classification action. Upon receipt of the coarse particles, the coarse particles overcome this air flow and fall due to the action of gravity, and the coarse particle discharge port 210c.
On the other hand, the dust (fine powder) rides on this air flow and becomes a dust-containing air flow and becomes a swirling air flow. And the rotor 2
Immediately before going to 80, the secondary classifying action is performed by the protruding plate 290a of the valve plate 290 located below the rotary blade 280. The second classifying action is that the coarse particles in the dust are distributed relatively to the outer periphery of the upward swirling airflow, and are blocked by the lower surface of the projecting plate 290a and fall, and only the fine particles in the dust communicate with the swirling airflow. It is discharged from the pipe 292. The dust of the dust-containing gas flowing into the cyclone 300 from the connecting pipe 292 is collected and discharged from the dust discharge port 300b,
The clean air is passed through the circulation pipe 310 and again to the casing 21.
It is circulated within 0. The classification point of this device is operated by the number of rotations of the rotating shaft and the opening of the valve plate (the protruding length of the protruding plate).

As described above, in the crushed sand removing apparatus of the present invention, the power means used is a single variable speed electric motor 2.
It has only 20 and has a simple structure without using a casing as a double tube like the startate type air separator described in the conventional example, and is easy to assemble, inspect, and disassemble, and contains the target crushed sand. The dust inside can be easily removed. In addition, the classification point of the dust to be removed can be easily changed, and it does not require any skill in driving operation, so handling is easy. In addition, since the air flow is one flow in the casing and there is no internal circulation, the pressure loss in the device is small and the power cost is reduced accordingly.

[0013]

The crushed sand dust removing apparatus of the present invention has a simple structure and a low initial cost, has a low power cost, and can easily remove the dust contained in the crushed sand produced to a required particle size. it can. Therefore, high quality crushed sand can be manufactured at low cost. In addition, it is easy to assemble, inspect, and disassemble the equipment, so it has excellent maintainability.

[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 a plan view of a crushed sand dust removing device according to an embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a main part of a crushed sand dust removing device according to an embodiment of the present invention.

FIG. 4 is a perspective view taken along line XX of FIG.

FIG. 5 is a flow sheet of a conventional sand breaking plant.

FIG. 6 is a particle size distribution curve diagram in each step of the crushed sand plant.

FIG. 7 is a vertical sectional view of a startate type air separator.

FIG. 8 is an explanatory diagram showing the flow of powder and air in the startate type air separator.

FIG. 9 is a perspective view of a startate type air separator.

[Explanation of symbols]

 10 raw material bottle 20 vibrating feeder 30 cone crusher 40 vibrating sieve 50 separator 100 startate type air separator 200 crushed sand dust removing device 210 casing 210a cylindrical pipe 210b conical pipe 210c coarse particle discharge port 220 variable speed electric motor 230 reducer 240 rotating shaft 250 dispersion plate 260 support 270 raw material supply pipe 270a input port 280 rotor blade 282 air inflow pipe 290 valve plate 290a protruding plate 292 communication pipe 300 cyclone 300a exhaust port 300b dust discharge port 310 circulation pipe 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 Rotating shaft I Coarse grain discharge port J Guide vane K Fine powder outlet M Variable speed electric motor Cold air inlet Q warm air outlet

Claims (1)

[Claims] 1. A charging pipe for supplying crushed sand powder and granules, a dispersion plate composed of a horizontal disk rotatable around a vertical axis, a rotary blade for generating a swirling upward air flow, and a horizontal plate arranged directly below the rotary blade. A single cylinder provided with a valve plate composed of a horizontal flat plate that can move back and forth in a direction, and a tubular casing, and the casing is provided with a discharge pipe through which a swirl upward airflow of the casing is discharged in a cut line direction. A crushed sand dust removing device in which a cyclone for collecting dust is connected to the discharge pipe, and an air inlet is provided at a lower portion of the casing.