JPH05285411A - Removing device for dust of crushed sand - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a crushed sand dust removing device that can easily and arbitrarily remove dust (fine powder) in crushed sand, has low initial cost, low running cost, and easy operation. [Structure] A central shaft 240 of a casing 210 having a single barrel shape
Distributor plate 250 is rotatably mounted on the dispersion plate 250, a raw material feeding pipe 270 for supplying crushed sand is provided on the disperser plate 250, and a rotor 280 is supported above the casing 210 by a support 280.
A valve plate 2 which is fixed to the dispersion plate 250 via a and is composed of a horizontal flat plate which is movable inward and backward and protrudes inside the casing.
90 is arranged immediately below the rotor 280, and the casing 210
The bottom plate 210b of the crushed sand and the bottom plate 21
The casing 210 was equipped with a scraper for sweeping through 0b, and a connecting pipe and a cyclone for discharging the swirling upward airflow were connected to the upper 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 produced in the quarry 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.
Are crushed by, and sieved by a vibrating screen 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 aggregates, which is less than 74 m and less than 7%, is 7% or less of the total amount. Since dust contamination adversely affects the quality, 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 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 given a centrifugal force and an inertial force by the prosthetic blade d to be 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 conveyed spirally 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 to become the swirl rising airflow, and repeats the separating action while circulating. The rotation speed of the rotation axis n is set by the specific gravity of the powder or granules, the shape of the particles, and the cut point, and the number of auxiliary blades d in the design also contributes to the setting of the cut point, but 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 has the effect of fine adjustment, and the smaller the opening (protruding more toward the inside), the finer the classification point.

[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 apparatus for removing crushed sand dust of the present invention, a horizontal disk is attached to a rotary shaft that hangs down to the central axis in a single-body cylindrical casing. Distributor plate is rotatably arranged and
An input pipe for supplying powdered particles of crushed sand is provided on the dispersion plate, and a rotary blade composed of a plurality of vertical flat plates on the circumference of the casing is fixed to the dispersion plate via a support. A plurality of valve plates, each of which is composed of a horizontal flat plate that can move back and forth inward from a casing directly below the casing, are provided around the casing. A discharge pipe for discharging the swirl upward airflow in the casing in the cutting line direction at the uppermost part of the casing, connecting a cyclone for collecting dust to the discharge pipe, and exhausting the cyclone. A configuration is provided in which an airflow circulation path connecting the port and the air intake port at the bottom 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 and are evenly distributed in the circumferential direction horizontally. Is radiated to the air, is introduced from the air intake, and the swirl upward airflow flowing in the casing by the rotation of the rotor blades causes
Due to the classification effect due to the difference between the upward drag force exerted by the air flow and gravity, the coarse particles overcome the drag force of the air flow and fall to the bottom of the casing by their own weight, and are swept over the bottom by the scraper rotating with the dispersion plate. Is discharged from the discharge port to the outside of the machine. Further, dust (fine powder) contained in the crushed sand rides on the swirl upward airflow and goes to the cyclone through the discharge pipe together with the swirl upward airflow, and at this time, the protrusion length of the valve plate arranged immediately below the rotor blade The coarse particles in the fine powder are removed by the secondary classification effect of the adjustment, and the coarse particles are discharged to the coarse particle discharge port. The dust in the dust-containing gas thus entering the cyclone is collected by the cyclone, and the clean air after the dust collection is reintroduced into the casing from the air inlet via the circulation path.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 and 2 show an embodiment of the present invention,
FIG. 1 is an overall vertical cross-sectional view of the crushed sand dust removing device, and FIG. 2 is a plan view of the crushed sand dust removing device. In the figure, a crushed sand dust removing device 200 is a horizontal shaft fixed to a rotatable rotary shaft 240 via a variable speed electric motor 220 and a chain (or V-belt) 230 on the upper central axis of a single-body cylindrical casing 210. A disk-shaped dispersion plate 250 is attached, and a raw material supply pipe 270 having a charging port 270a for charging the raw material onto the dispersion plate 250 is provided around the rotary shaft 240, and further above the casing 210, the diameter is larger than the diameter of the casing 210. By providing an upper casing 210a having a diameter,
A support 28 in which a plurality of rotary blades 280, which are vertical flat plates and are arranged at an equal pitch around the circumference, are fixed to the dispersion plate 250, is provided.
It is arranged via 0a. A bearing 280b is disposed between the support 280a and the lower end of the raw material feeding pipe 270. In addition, the casing 210 is provided directly below the rotor 280.
A plurality of valve plates 290 having a protruding plate 290a formed of a horizontal flat plate that can be moved inward and backward from (the lower end portion of the upper casing 210a actually) are arranged around the circumference. 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 adopted.

The bottom plate 210b at the bottom of the casing 210
An outlet 210c for the coarse particles of crushed sand is provided at one position on the circumference of, and a scraper 242 for sweeping the upper surface of the bottom plate 210b is attached to the rotary shaft 240. Reference numeral 240a
Is a bearing that supports the rotating shaft 240. Further, as shown in FIG. 2, the upper casing 210a is provided with an opening at the uppermost circumference, and the swirling airflow flowing by the rotation of the rotor blades 280 is discharged in the tangential direction of the upper casing 210a, and the cyclone is installed downstream. A connecting pipe 292 leading to 300 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 at the bottom of the casing 210. Although the air inflow pipe 282 is provided orthogonal to the casing 210 toward the center of the casing 210, it may be attached tangentially in the direction of the swirling airflow generated in the casing 210, that is, in the rotating direction of the rotor 280. .. In this embodiment, cyclone 3
Although the circulation pipe 310 is provided between the exhaust port 300a of No. 00 and the air inflow pipe 282 to circulate the air, the clean air after the dust collection of the cyclone 300 is released to the atmosphere as it is, and is naturally discharged to the casing 210. A method of inflowing the atmosphere may be used.

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 blades 280 rotate integrally via the chain 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 are gravitationally dropped to the bottom plate 210b and swept by the scraper 240 toward the coarse particle discharge port 210c, while the dust (fine powder) is contained in the air stream. It becomes a dust air flow and a swirling air flow. Immediately before going to the connecting pipe 292, the secondary classifying action is performed by the protruding plate 290a of the valve plate 290 below the connecting pipe 292. The second classifying action is that the coarse particles in the dust are distributed relatively toward the outer periphery of the upward swirling airflow, and the protruding plate 29
It is blocked by the lower surface of 0a and falls, and only the fine powder in the dust is discharged from the connecting pipe 292 together with the swirling airflow. Connecting pipe 2
The dust of the dust-containing gas flowing into the cyclone 300 from 92 is collected and discharged from the dust discharge port 300b, and the clean air is circulated again in the casing 210 via the circulation pipe 310. 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.
No. 20 is required, and unlike the startate type air separator described in the conventional example, the structure is simple without using a double pipe for the casing, easy to assemble, inspect, and disassemble, and to contain the target crushed sand. The dust inside can be easily removed. In addition, the classification point of the dust to be removed can be changed easily, and it does not require any skill in 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 device of the present invention has a simple structure and a low initial cost, and also 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, and 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 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 a vertical cross-sectional view of a 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 removing device 210 Casing 210a Upper casing 210b Bottom plate 210c Discharge port 220 Variable speed electric motor 230 Chain (or V belt) 240 Rotating shaft 240a Bearing 242 Scraper 250 Dispersion plate 270 Raw material input pipe 270a Input port 280 Rotor blade 280a Support 280b Bearing 282 Air intake pipe 290 Valve plate 292 Communication pipe 300 Cyclone 300a Exhaust 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 m Annular space n Rotating shaft I Coarse grain discharge port J Guide vane K Fine powder outlet M Speed motor P cold air inlet Q warm air outlet

Claims (1)

[Claims] 1. A dispersion plate composed of a horizontal disk is rotatably arranged on a rotary shaft hanging down from a central axis in a single-body cylindrical casing, and powdered particles of crushed sand are supplied onto the dispersion plate. A charging pipe is provided, and a rotor composed of a plurality of vertical flat plates around the circumference of the casing is fixedly mounted on the dispersion plate via a support, and a horizontal blade that can move back and forth inward from the casing immediately below the rotor. A plurality of flat valve plates are arranged around the circumference, a crushed sand discharge port is provided on the bottom surface of the casing, and a scraper for sweeping the top surface of the bottom surface is fixed to the rotary shaft, and the casing is provided on the top of the casing. A discharge pipe for discharging the swirling upward airflow in the direction of the cut line is provided, and a cyclone for collecting dust is connected to the discharge pipe, and an exhaust port of the cyclone and an air intake port under the casing are connected. Of the air flow Crushed sand dust remover equipped with a circulation path.