JP2709672B2 - Crushed sand dust removal equipment - Google Patents

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 apparatus used for removing fine powder (dust) in crushed sand produced by a crusher used in a crushed sand plant.

[0002]

2. Description of the Related Art In recent years, the production of crushed sand in the quarrying industry has been increasing year by year due to the depletion of natural sands (river sand, mountain sand, land gravel, sea sand), and the demand for such sand is continually increasing. . In the crushed stone production method, there has conventionally been a crushing sand plant that uses a crusher that divides mined rock, and the crushing operation by the crusher necessarily inevitably produces fine powder smaller than a desired size. FIG. 3 shows a flow sheet of a conventional sand crushing plant.
, And sieved by the 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 classified into crushed sand and fine powder (dust) smaller than the crushed sand by classification. Qf, Qc, Qr, Qp, Qd, Qs in FIG.
Indicates the production amount 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 raw material particle size is crushed and the undersize after sieving is as follows. This crushed sand contains about 5 to 10% dust, and as a result of classification, the final product is obtained (the particle size distribution of dust), but falls within the range of two dotted lines specified in JIS crushed sand standard. Crushed sand that meets the standard. Also J
According to the IS standard, the amount of dust of 74 m or less contained in the aggregate should be 7% or less of the total amount. Since the contamination of dust 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 approximately 400 μm or less, and a startervant type air separator 100 is used as the air separator 50 for removing the dust from the crushed sand. FIG. 5 is a longitudinal sectional view of the starter band type air separator 100. A dispersion plate c is mounted on a vertical rotation axis n driven by a variable speed motor M on a central axis of a can body composed of an outer casing i and an inner casing f. , A main blade e and an auxiliary blade d are fixed and rotate. The raw material supplied from the raw material supply port a to the dispersion plate c via the chute b is applied with a centrifugal force by the dispersion plate c, and is radially and horizontally discharged radially and evenly toward the inner casing f. The circulating swirling airflow generated by the rotation of e becomes an ascending swirling airflow in the inner casing f, carries fine powder among the dispersed raw material particles upward, and passes through the auxiliary blade d. At this time, the granular material is given centrifugal force and inertia force by the rib rib 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 inertia force collide with the inner surface of the inner casing f, settle down 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 removed from the inner casing f.
And the outer casing i is conveyed to the annular space m, where centrifugal force is given by the annular descending swirling airflow, the helical air is conveyed downward along the inner wall surface of the outer casing i, and discharged from the lower fine powder outlet K by gravity. Is done. Annular space m in the figure
The circular swirling airflow that has passed through is sucked inward from the guide vanes J provided at the intermediate portion of the inner casing f, and repeats the separation operation while circulating as the above-described swirling ascending airflow. The number of revolutions of the rotating shaft n is set by the specific gravity of the powder and the shape of the fine particles and the classification point (Cut Point), and the number of auxiliary blades d in the design is also involved in the setting of the classification point. Adjustment is the main blade e
This is controlled by adjusting a horizontally expandable and contractible valve plate g provided between the auxiliary blade d. P and Q are air inlets and outlets for heat exchange.

As described above, 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. In addition, although the air volume is increased by increasing the rotation speed of the rotating shaft n, the classification point is also changed at the same time. The auxiliary blade d is used for adjusting fineness (classification point), and becomes finer as the number of blades is increased. The valve plate g is the handle h
Is used for adjusting the fineness in the same way, and it is effective for fine adjustment. If the opening is made small (it projects much inward), the classification point becomes fine.

[0006]

The removal of dust from crushed sand in the crushing industry has a relatively short history, and there is currently no definitive classifier for dry removal of fines (dust) in crushed sand. Therefore, as described above, an existing high-class classifier such as a startervant type air separator is used, but the initial cost is higher than the purpose, the power consumption is large, and the classification operation is relatively difficult. There has been a demand for the development of a crushed sand dust removal apparatus suitable for dust processing, which has disadvantages, low classification accuracy, low power consumption unit, and low initial cost. In addition, the wet method of washing the dust contained in the crushed sand with water has the disadvantage that the washing, drying and wastewater treatment processes are newly added to the crushed sand plant, increasing initial costs and running costs, and increasing production costs. there were.

[0007]

In order to solve the above-mentioned problems, in the crushed sand dust removing apparatus according to the present invention, a horizontal disk is attached to a rotating shaft hanging down from a central axis in a single cylindrical cylindrical casing. Dispersing plate is rotatably arranged,
A feed pipe for supplying the powdered granules of the crushed sand is provided on the dispersion plate, and a rotating blade made up of a plurality of circumferential flat plates is fixed to the dispersion plate via a support at an upper portion of the casing. A plurality of valve plates, each of which is a horizontal plate that is movable inward and backward from the casing immediately below the casing, are provided on the circumference thereof, and a discharge port for crushed sand is provided on the bottom surface of the casing, and the scraper for sweeping the top surface of the bottom surface is connected to the rotary shaft. A discharge pipe is provided at the top of the casing for discharging the swirling airflow in the casing in the direction of the dashed line, a cyclone for collecting dust is connected to the discharge pipe, and the exhaust of the cyclone is performed. An airflow circulation path connecting the mouth and the air intake at the lower part of the casing was provided.

[0008]

Since the present invention is constructed as described above, the powder and granules supplied onto the dispersing plate from the raw material charging pipe are centrifugally applied by the rotating dispersing plate to be substantially evenly distributed in the circumferential direction. Is swirled up by the swirling airflow that is radiated into
Due to the classification effect due to the difference between the upward drag and gravity caused by the airflow, the coarse particles fall down to the bottom of the casing by their own weight, overcoming the drag of the airflow, and are swept over the bottom by the scraper rotating with the dispersion plate. Is discharged out of the machine through the discharge port. The dust (fine powder) contained in the crushed sand rides on the above-mentioned swirling updraft and travels through the discharge pipe to the cyclone together with the swirling updraft. At this time, the projecting length of the valve plate disposed immediately below the rotor blades is reduced. The coarse particles in the fine powder are removed by the secondary classification by the adjustment, and are directed to the coarse particle discharge port. The dust in the dust-containing gas entering the cyclone in this way is collected by the cyclone, and the clean air after the dust collection is again introduced into the casing from the air inlet through the circulation path.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show an embodiment of the present invention.
FIG. 1 is an overall vertical 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 horizontally mounted on a rotatable rotating shaft 240 via a variable speed motor 220 and a chain (or V belt) 230 on an upper central axis of a single cylindrical cylindrical casing 210. A disk-shaped dispersion plate 250 is attached, and a raw material supply pipe 270 having an inlet 270a for charging the raw material onto the dispersion plate 250 is provided around the rotary shaft 240. By providing an upper casing 210a having a diameter,
A support 28 in which a plurality of rotating blades 280 formed of vertical flat plates and arranged at equal circumferential intervals is fixed to a dispersion plate 250.
0a. A bearing 280b is provided between the support 280a and the lower end of the raw material introduction pipe 270. The casing 210 is located immediately below the rotor 280.
A plurality of valve plates 290 having a protruding plate 290a made of a horizontal flat plate that can move inward and backward from the (actually, the lower end portion of the upper casing 210a) are provided. As the means for moving the valve plate 290 forward and backward, a power means such as an air cylinder, a hydraulic cylinder, or an electric motor can be employed in addition to manual operation.

The lowermost bottom plate 210b of the casing 210
A discharge port 210c for coarse particles of crushed sand is provided at one location on the circumference of the circle, and a scraper 242 for sweeping the upper surface of the bottom plate 210b is attached to the rotating shaft 240. Code 240a
Is a bearing that supports the rotating shaft 240. Further, an opening is provided at one location on the uppermost circumference of the upper casing 210a, and as shown in FIG. 2, the swirling airflow flowing by the rotation of the rotary blade 280 is discharged in the tangential direction of the upper casing 210a, and the cyclone installed downstream is provided. A communication pipe 292 leading to 300 is provided. As the cyclone 300, a cut-line inflow type cyclone or a spiral cyclone which is usually used is used. A circulation pipe 310 is connected between an exhaust port 300a of the cyclone 300 and an air inflow pipe 282 provided at a lower portion of the casing 210. Although the air inflow pipe 282 is provided orthogonal to the casing 210 toward the center of the casing 210, the air inflow pipe 282 may be attached tangentially in the direction of the swirling airflow generated in the casing 210, that is, in the direction of rotation of the rotor 280. . In this embodiment, the cyclone 3 is used.
A circulation pipe 310 is provided between the exhaust port 300a and the air inflow pipe 282 to circulate the air. However, the clean air after the cyclone 300 is collected is discharged to the atmosphere as it is, and is naturally discharged to the casing 210. A method of flowing air may be used.

The operation of the crushed sand dust removing apparatus of the present invention configured as described above will be described. Variable speed motor 22
By the drive of 0, the rotating shaft 240, the dispersion plate 250, and the rotating blade 280 rotate integrally via the chain 230. The raw material powder (crushed sand) supplied from the input port 270a of the raw material input pipe 270 receives centrifugal force by the dispersing plate 250 and is radiated from the dispersing plate 250 substantially horizontally in a spiral shape to the surrounding space. On the other hand, in the casing 210, the air introduced from the air inlet pipe 282 forms a swirling upward airflow by the rotation of the rotary blade 280, and the powder particles discharged around the dispersion plate 250 by this airflow have a classifying effect. The coarse particles overcome this air flow and fall to the bottom plate 210b by the action of gravity and are swept by the scraper 240 toward the coarse particle discharge port 210c, whereas dust (fine powder) rides on this air flow and is contained. It becomes dust flow and turns to swirl flow. Immediately before heading to the connecting pipe 292, the second classifying operation is performed by the projecting plate 290a of the valve plate 290 below the connecting pipe 292. In the second classifying operation, the coarse particles in the dust are distributed relatively near the outer periphery of the upward swirling airflow.
Oa is blocked by the lower surface, and only the fine powder in the dust is discharged from the communication 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 through the circulation pipe 310 into the casing 210. The operation of the classification point of the present apparatus is performed based on the rotation speed of the rotating shaft and the opening degree of the valve plate (projection length of the projection plate).

As described above, in the apparatus for removing crushed sand dust of the present invention, the power means used is a single variable speed motor 2.
Unlike the startervant type air separator described in the conventional example, the casing is simple, the structure is simple, the assembly, inspection, and disassembly are easy. The dust inside can be easily removed. Further, it is easy to change the classification point of the dust to be removed, and it is easy to handle because there is no need for skill in operation. In addition, since the air flow is a one-way 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, low initial cost, low power cost, and can easily remove dust contained in the produced crushed sand to a required particle size. it can. Therefore, high quality crushed sand can be produced at low cost. In addition, the equipment is easy to assemble, inspect, and disassemble, so that maintenance is excellent.

[Brief description of 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.

FIG. 2 is a plan view of the crushed sand dust removing device according to the embodiment of the present invention.

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

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

FIG. 5 is a longitudinal sectional view of a startervant type air separator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Raw material bottle 20 Vibration feeder 30 Cone crusher 40 Vibrating sieve 50 Separator 100 Starter band type air separator 200 Crushed sand dust removal device 210 Casing 210a Upper casing 210b Bottom plate 210c Discharge port 220 Variable speed 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 Connecting 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 Rotary axis I Coarse grain outlet J Guide vane K Fine powder outlet M Speed motor P cold air inlet Q warm air outlet

Claims (1)

(57) [Claims] 1. A dispersing plate made of a horizontal disk is rotatably disposed on a rotating shaft hanging down from a central axis in a single cylindrical cylindrical casing, and powdered granules of crushed sand are supplied onto the dispersing plate. A charging pipe is provided, and a rotating blade made of a plurality of vertical flat plates is fixed to the dispersion plate via supports at the upper part of the casing, and a horizontal wing that can move inward and backward from the casing immediately below the rotating blade is provided. A plurality of valve plates made of flat plates are arranged around the circumference, a discharge port for crushed sand is provided on the bottom surface of the casing, and a scraper for sweeping the upper surface of the bottom surface is fixed to the rotating shaft. A discharge pipe is provided for discharging the swirling upward airflow in the cut line direction, a cyclone for collecting dust is connected to the discharge pipe, and an exhaust port of the cyclone is connected to an air intake port at a lower portion of the casing. Of the flowing air A crushed sand dust removal device equipped with a circulation path.