JP2783346B2 - 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 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. 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 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 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 apparatus for removing crushed sand dust according to the present invention, a supply of powdered crushed sand is supplied to the center of the upper end of a single cylindrical casing. A pipe is provided, and a cone for dispersing the granular material charged into the surroundings below the charging pipe is disposed. Under the cone, an inverted cone-shaped coarse particle made of a perforated plate, expanded metal or wire mesh is provided. A guide cone is fixed to the casing, an air inlet pipe is provided at a lower part of the casing, an exhaust pipe is provided at an upper part of the casing, and a cyclone for collecting dust in dust-containing gas, an air volume control valve, and a suction fan are exhausted. Connect downstream of the pipe, between the suction fan and the air inlet pipe
A circulation path was provided .

[0008]

Since the present invention is constructed as described above, the crushed sand particles of the raw material supplied from the charging pipe to the inside of the casing come into contact with the cone and are scattered in all directions and fall to the coarse-grain guide cone. Move down along the slope. At this time, the air introduced into the casing from the air inflow pipe becomes an ascending airflow by the suction force of the suction fan, passes through the coarse-grain guide cone, and travels toward the exhaust pipe. Is accompanied by a dust-containing gas to enter the cyclone where dust is collected. The adjustment of the classification point of coarse particles and dust is adjusted by the flow rate of the rising airflow flowing through the casing, and the operation is controlled by opening and closing the air volume control valve in front of the suction fan.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall longitudinal sectional view of a crushed sand dust removing apparatus according to an embodiment of the present invention, and FIG. 2 is an overall longitudinal sectional view of a crushed sand dust removing apparatus according to another embodiment of the present invention. FIG.
, The crushed sand dust removing device 200 includes a single cylindrical casing 210, a cyclone 300 connected thereto, an air volume control valve 410, and a suction fan 400.
Immediately below the conical body 240, a conical cone 240 is disposed, and an inverted conical coarse grain 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 perforations in the perforated plate is 5 to 10 times the size of the dust particles in consideration of the particle size of the dust to be removed. The center of the coarse-grain guide cone 220 is the coarse-grain discharge pipe 2.
50 are connected. An air inlet pipe 260 is provided at the lower side of the casing 210, and an exhaust pipe 270 is provided at one upper end of the casing 210 diagonally from the air inlet pipe 260.
The subsequent cyclone 300, the air volume 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 circulating path 500 and the circulating path 500.

FIG. 2 shows an apparatus for removing crushed sand dust according to another embodiment of the present invention. Only the points different from FIG. 1 will be described. An extended guide cone 220a is provided.
Next, an inverted conical second coarse-grain guide cone 220b is fixed to the inner surface of the casing 210, and the air inflow pipe 260 is formed so as to surround the periphery of the coarse-grain discharge pipe 250 connected to the lower center of the coarse-grain guide cone 220b. A lower casing 210a having substantially the same shape as that of the coarse-grain guide cone 220b is provided thereon, and an exhaust pipe 270 is also provided so as to surround the inlet pipe 230.
It is intended that the rise of the air be performed in a symmetrical manner with respect to the central axis.

The operation of the crushed sand dust removing apparatus of the present invention configured as described above will be described. Suction fan 400
Is driven to form a rising air flow in the casing 210, when the crushed sand particles are supplied from the charging pipe 230, they are dispersed in four directions by hitting the cone 240, and each particle is coarsely guided by the coarse guide cone 220 (or 220a). And 220b) and move down the slope. At this time, the fine particles (dust) in the granular material ride on the ascending air current which blows up from the through-hole of the coarse-grain guide cone 220 on the slope and is discharged as a dust-containing gas from the exhaust pipe 270, and the coarse particles fall down the slope as it is. And coarse discharge pipe 25
0 to the outside of the casing 210. Exhaust pipe 270
The discharged dust-containing gas enters the cyclone 300, where the dust is collected. The clean air exits through the exhaust pipe 300c, passes through the air flow control valve 410, the suction fan 400, and again into the casing 210 from the air inflow pipe 260. Enter and circulate. 3
00a is an inlet pipe of the cyclone 300, and 300b is a fine powder discharge pipe. The adjustment of the classification point of the coarse particles and the fine powder (dust) is controlled by the air volume of the rising airflow flowing in the casing, and is performed by adjusting the opening of the air volume control valve 410 in front of the suction fan 400.

The apparatus for removing crushed sand dust according to the present invention has no moving parts other than the formation of an airflow in the casing by a suction fan, has a simple structure, is easy to assemble, inspect, disassemble and repair, and classifies the dust to be removed. The points can be easily changed and the handling is simple. 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 apparatus according to the present invention has a simple structure and low initial cost, has a low power cost, and can remove dust contained in the produced crushed sand.
Control the classification point by opening and closing the air flow control valve
Thereby, the particles can be easily removed to a required particle size. Therefore, high quality crushed sand with little dust can be produced at low cost, and the apparatus is easy to assemble, inspect, and disassemble, so that the maintainability 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 an overall vertical sectional view of a crushed sand dust removing apparatus according to another 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 an overall vertical 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 Vibrating sieve 50 Separator 100 Starter band type air separator 200 Crushed sand dust removal device 210 Casing 210a Lower casing 220 Coarse guide cone 220a Coarse guide cone 220b Coarse guide cone 230 Input pipe 240 Conical 250 Coarse-particle 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 Airflow control valve 500 Circulation path a Raw material supply port b Shoot 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 axis I Coarse grain outlet J Guide vane K Fine powder outlet M Variable speed motor P Cold air inlet Q Air outlet

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B07B 4/00-11/08

Claims (1)

(57) [Claims] An injection pipe for supplying crushed sand particles is provided at the center of the upper end of a single cylindrical casing, and a conical body for dispersing the powder particles introduced below the input pipe to the surroundings is provided. A perforated plate, an inverted cone-shaped coarse-grained guide cone made of expanded metal or wire mesh is fixed to the casing below the cone, an air inlet pipe is provided at a lower portion of the casing, and an exhaust gas is provided at an upper portion of the casing. a suction fan and cyclone and air volume control valve for a dust collecting in the dust-containing gas provided with a tube connected downstream of the exhaust pipe, the suction fan and air
A crushed sand dust removal device with a circulation path between the air inlet pipe.