JP2724652B2 - 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. 4 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. 5 shows a particle size distribution curve diagram in each step of the flow sheet of FIG. 4, 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 μm 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. 6 shows a longitudinal sectional view of the starter band type air separator 100, in which 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 inertial force by the auxiliary blade d, separated into coarse particles and fine powder, and only the fine powder is 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 rotations 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 the supporting ribs d is involved in the setting of the classification point by design. The adjustment is controlled by adjusting a horizontally expandable and contractible 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.

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 rib rib 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 crushed sand in the crushing industry has a relatively short history, and there is currently a decisive device for efficiently and efficiently removing fine powder (dust) contained in crushed sand. do not do. Therefore, it is a fact that existing high-class classifiers such as the above-mentioned startervant type air separators are unavoidably used, but the initial cost is lower than the purpose of removing the gust in the crushed sand. It has disadvantages such as high power consumption, large power consumption, and relatively difficult classification operation. Classification accuracy is not so high, power consumption is low, and the initial cost is low. The advent of a dust removal device has been desired. 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]

According to a first aspect of the present invention, there is provided an apparatus for removing crushed sand dust according to the present invention. A dispersing plate consisting of a horizontal disk is disposed in the middle of the shaft, and a supply pipe for supplying the powdery material of the crushed sand is provided on the dispersing plate. A plurality of dust-containing gas discharge pipes are provided on the upper side wall of the casing, and a cyclone for collecting dust is connected to the discharge pipe. And an airflow circulation path connecting the air inflow pipe provided in the above. Also,
In the second invention, a guide cone made of a perforated plate, a conical crushed sand powder body formed by expanded metal or a wire mesh is disposed below the dispersion plate in the casing of the apparatus of the first invention.

[0008]

Since the present invention is constructed as described above, the dispersion plate and the rotating blades are rotated by rotating the rotating shaft, so that an upward swirling airflow vertically rising from the lowermost portion of the casing is formed. In the meantime, the crushed sand granules of the raw material supplied from the input pipe onto the dispersion plate are centrifugally applied by the rotating dispersion plate, are radiated almost uniformly in the circumferential direction, fall down in a parabolic shape, and fall into the casing. Fall near the surrounding wall.
At this time, the dust in the crushed sand encounters the upward swirling airflow, is carried by the airflow, is discharged together with the airflow from a discharge pipe on a side wall at an upper portion of the casing, and is collected by a cyclone. On the other hand, the coarse particles in the crushed sand are not affected by this upward swirling airflow, and the gravity of the coarse particles themselves falls below the drag of the airflow, and is discharged from the coarse particle outlet at the bottom of the casing. You. The above is the operation of the crushed sand dust removing device according to the first invention. In the second invention, the dispersion is guided by a guide cone formed of a perforated plate, expanded metal, or a wire mesh below the dispersion plate. Since the crushed sand particles that have overflowed from the plate fall and roll or slide, there is more chance to encounter an updraft from below, and more dust is removed. Although coarse particles and dust are separated as described above, the classification point is controlled by the rotation axis, that is, the rotation speed of the rotor, and the higher the rotation speed, the larger the particle size of the removed dust.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 relate to an embodiment of the present invention.
FIG. 1 is an overall vertical sectional view of a crushed sand dust removing device, FIG. 2 is a plan view of the crushed sand dust removing device, and FIG. 3 is an overall longitudinal sectional view of another embodiment of the crushed sand dust removing device. In the figure, a crushed sand dust removing device 200 is a single-body cylindrical casing 210.
And a cyclone 300 connected thereto. The casing 210 comprises a cylindrical tube 210a and a conical tube 210b connected to the cylindrical tube 210a. An input tube 270 is disposed below the center of the top plate 210c of the casing 210, and a rotary shaft 240 is mounted at the center thereof via a bearing 240b. Chain wheel (or V pulley) attached to the upper end
Roller chain (or V-belt) 230 through 40a
Thus, the rotary drive is performed by a chain wheel (or V pulley) 220a attached to the output shaft of the variable speed motor 220.

A dispersing plate 250 made of a horizontal disk is fixedly mounted in the middle of the rotating shaft 240, and rotating blades 280 made of a vertical flat plate are uniformly arranged around the lower end of the rotating shaft 240 to support the support 280a. And the rotation shaft 240 and the dispersion plate 250 can be integrally rotated. A dust-containing gas discharge pipe 212 is attached tangentially at one circumferential position on the upper side wall of the cylindrical pipe 210a of the casing 210, and a coarse-grain discharge port 210d is provided at the lower end of the conical pipe 210b of the casing 210. At the same time, an air intake pipe 260 that stands vertically upward is provided. On the upper end of the air intake pipe 260, a conical garbage cap 262 is provided for reversing the introduced airflow and rising along the inner peripheral wall of the conical pipe 210b, and attached to the falling coarse particles. It plays the role of sowing dust. On the other hand, the discharge pipe 2
12 is an inlet pipe 300 of a cyclone 300 for collecting dust.
The exhaust gas after dust collection is connected to the casing 210 via the circulation path 400 connected to the air intake pipe 260 via the exhaust port 300c.

FIG. 3 shows a crushed sand dust removing apparatus showing another embodiment. The difference from the embodiment shown in FIG. 1 will be described. The perforated flat plate, expanded metal, wire mesh, or the like is provided beside or below the dispersion plate 250. A guide cone 290a, 290b having a molded conical shape is provided, and the dispersion plate 25 is provided.
The crushed sand particles overflowing from the inside of the casing 210 are prevented from falling along the inner peripheral wall of the casing 210, and the guide cone 290 is prevented.
When rolling or sliding on a and 290b sequentially, the dust swirled up by the upward swirling airflow introduced into the casing and separated from the coarse particles is separated and removed from the coarse particles. Therefore, in the case of FIG.
The guide cones 90a and the conical guide cones 290b are arranged alternately. However, the shape of the guide cones is not limited to these shapes, and any shape may be used as long as the powder particles falling from the dispersion plate 250 descend sequentially. It may be something like that. Also,
In the embodiment of FIG. 3, a suction fan 500 is provided in the middle of the circulation path 400 via the air volume control valve 510 to make the circulation airflow between the casing 210 and the cyclone 300 stronger.

The operation of the crushed sand dust removing apparatus of the present invention configured as described above will be described. Variable speed motor 22
0 drives the roller chain (or V belt) 230
, The rotating shaft 240, the dispersion plate 250, and the rotating blade 280 rotate integrally. The raw material (crushed sand granules) supplied from the input port 270a of the input pipe 270 receives the centrifugal force from the dispersion plate 250, moves spirally to the outer peripheral side, and is discharged substantially horizontally from the dispersion plate 250 to the surrounding space. You. On the other hand, in the casing 210, the airflow flowing from the air intake pipe 260 at the lower end of the casing 210 flows toward the discharge pipe 212 on the upper side wall of the casing 210 as a swirling ascending airflow due to the rotation of the rotary blade 280. Of the particles that fall freely around 250, the coarse particles move to the lower coarse particle discharge port 210d as they are, while the dust (fine powder) contained in the particles is included along with this air flow. Dust gas is introduced into the cyclone 300 through the discharge pipe 212, collected, and taken out from the fine powder discharge port 300b. In this way, the powder supplied onto the dispersion plate 250 is
In the space around 50, coarse sand and dust (fine powder) are separated, and crushed sand consisting of only coarse particles from which dust has been removed can be obtained from the coarse particle outlet 210d. Adjustment of the classification point of coarse particles and dust is performed by increasing or decreasing the number of revolutions of the rotor 280, and the higher the speed, the more the gust having a larger particle size can be removed. That is, when the rotation speed is increased to increase the flow rate of the circulating airflow in the casing, the classification point is raised. Conversely, when the rotation speed is reduced, the maximum particle size of dust mixed into the coarse particles is increased.

As described above, in the crushed sand dust removing apparatus of the present invention, only a single variable speed motor is used as the power means, and two casings are used as in the startervant type air separator described in the conventional example. The structure is simple without using heavy pipes, easy to assemble, inspect, disassemble and repair, and easily remove dust contained in crushed sand. Further, the classification point of the dust to be removed can be easily changed, and no skill in operation is required, so that the handling is easy. In addition, the flow of air is one-way in the casing, and since there is no internal circulation, the pressure loss in the device is small and the power cost can be reduced accordingly.

[0014]

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 an overall longitudinal sectional view of a crushed sand dust removing apparatus according to another embodiment of the present invention.

FIG. 4 is a flow sheet of a conventional sand crushing plant.

FIG. 5 is a particle size distribution curve diagram in each step of the crushed sand plant.

FIG. 6 is an overall longitudinal sectional view of a conventional startervant type air separator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Raw material bottle 20 Vibration feeder 30 Cone crusher 40 Vibration sieve 50 Separator 100 Starter band type air separator 200 Crushed sand dust removal device 210 Casing 210a Cylindrical tube 210b Conical tube 210c Top plate 210d Coarse grain discharge port 212 Discharge pipe 220 Variable speed motor 220a Chain foil ( Or V pulley) 230 Roller chain (or V belt) 240 Rotary shaft 240a Chain wheel (or V pulley) 240b Bearing 250 Dispersion plate 260 Air inflow pipe 262 Jinkasa 270 Input pipe 270a Input port 280 Rotating blade 280a Support 290a Guide cone 290b Guide cone 300 Cyclone 300a Inflow pipe 300b Fine powder discharge port 300c Exhaust port 400 Circulation path 500 Suction fan 510 Flow control valve 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 Rotary shaft I Coarse grain outlet J Guide vane K Fine powder outlet M Variable speed motor P Cold air inlet Q Hot air outlet

Claims (2)

(57) [Claims] 1. A dispersing plate composed of a horizontal disk is disposed in the middle of a rotating shaft hanging down from a central axis in a single cylindrical casing, and a powdery material of crushed sand is supplied onto the dispersing plate. A pipe is provided, and a plurality of rotating blades made of a vertical flat plate are attached to the lower end of the rotating shaft evenly around the circumference, and a discharge pipe for dust-containing gas is provided on an upper side wall of the casing. Sand dust removing device having an air flow circulation path connecting a cyclone for air and connecting an exhaust port of the cyclone and an air inlet pipe provided vertically at a lowermost portion of the casing. 2. A perforated plate under a dispersion plate in a casing,
2. The crushed sand dust removing device according to claim 1, further comprising a guide cone of a conical crushed sand powder formed by expanded metal or wire mesh.