JPH0418937A - Method and device for improving shape of crushed stone - Google Patents

Abstract

PURPOSE:To efficiently improve the shape of a crushed stone by moving the compressed surface so that the compression ratio is practically uniformized at the respective spots of the layer of the accumulated crushed stones with a compressive force limited to crush only the surface contact part between the crushed stones. CONSTITUTION:A hollow drum 1 is horizontally set with the center line inclined to horizontal. A rotary roller 17 piercing the hole part of the drum 1 and having an axis deviated from the center line of the drum 1 is provided. The pressure on the crushed stone between the inner surface of the drum 1 and the surface of the roller 17 is adjusted by a pressing down cylinder 15, and the drum 1 is rotated by a motor 19, etc. The supply means 9 and discharge means 10 for crushed stones are provided on one and the other end face sides of the drum 1. Namely, the shape of the crushed stone is efficiently, surely and easily improved by using the most economical compression method.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to crushed stone, particularly a method and apparatus for improving the particle shape of crushed stone suitable as aggregate for concrete, and more specifically,
This invention relates to a method and device for improving the surface of crushed stone to a shape with fewer sharp protrusions, like gravel naturally produced in rivers.

[Conventional technology]

Gravel naturally produced in rivers has few sharp protrusions on its surface, making it ideal as an aggregate for concrete.Using such aggregate increases the strength of concrete and improves the strength of cement. The amount used can be reduced.

However, in recent years, it has become difficult to obtain gravel naturally produced in rivers, and as an alternative, crushed stone, which is obtained by mining rock, crushing it, and granulating it, is used as aggregate. However, as shown in Figure 5, aggregates manufactured in this way often have sharp protrusions or flat shapes, and as a result, concrete is less effective than gravel produced naturally in rivers. There are problems in terms of strength and amount of cement used.

Gravel naturally produced in rivers has an ideal particle shape, so a method that approximates the friction caused by flowing rivers is to place crushed stones in a drum-shaped container and rotate them to agitate each other. . However, this method is not practical because it is difficult to apply large amounts of energy to the crushed stone in a short time to remove sharp protrusions on the surface of the crushed stone, and it takes a long time to achieve the objective.

So, what is currently in use?

There are the following methods.

■ A method that forces each part of the crushed stone layer to move in different directions, generating strong shearing force within the layer, and crushing and removing protrusions on the crushed stone surface.

■ A method of applying a mild impact to crushed stone to remove protrusions on its surface.

■ A method of filling the crushing chamber of a compression type crusher with crushed stones so that they are in contact with each other, and crushing the protrusions on the surface during compression.

[Problem to be solved by the invention]

Regarding method (2) above, there are two practical machines: one in which the screw is rotated in a sealed crushed stone, and another in which the crushed stone is placed in the middle of a double cylinder that rotates in different directions. However, all of these methods have the problem that strong friction occurs between the screw or cylindrical folds that transmit energy to the crushed stone and the crushed stone, and the cost of improving grain shape is high due to wear of the device, making it uneconomical. 6 Regarding method ① above, an impact crusher with a rotor attached to a vertical or horizontal shaft is used as a practical machine, and crushed stones collide with the rotor and accelerated crushed stones collide with other crushed stones. By doing so, the protrusions on the surface of the crushed stone are removed, but in some cases, these collisions may destroy not only the protrusions on the surface of the crushed stone but also the crushed stone itself.

In this case, not only will the size of the crushed stone become smaller than the desired size, but due to the characteristics of the crushed stone raw material, the shape of the crushed stone may be regenerated into one that is flat and has protrusions. There is a limit to Also.

When the high-speed rotor comes into contact with the crushed stone, the rotor wears out significantly, causing problems such as being uneconomical.

Furthermore, for the method (2) above, there are show crushers and cone crushers as practical machines.

However, this method is used to improve the particle shape of the crushed product when the main purpose is crushing, but it is rarely used when the purpose is to improve only one particle shape. In other words, in a crushing chamber where the compression surface oscillates, the compression ratio differs depending on the location, resulting in large differences in the compression force generated, and the layer that has been compressed to a certain degree is compressed again without being crushed much. Therefore, it is difficult to preferentially crush only the protrusions on the surface without crushing the inside of the crushed stone, and therefore there are problems such as the effect of improving grain shape is small.

The present invention was made in view of the above circumstances, and its purpose is to improve the particle shape of crushed stone by using the most economical compression method. The purpose is to provide an improved method and device.

[Means to solve the problem]

In accordance with the present invention, a method for improving the particle shape of crushed stone is provided, in which crushed stone is supplied between two facing compression surfaces, and when compressed by reducing the distance between the compression surfaces, the crushed stone is free-falling or A feeding process in which the crushed stones are fed in a flying state and deposited, and a compression surface is moved so that each layer of the accumulated crushed stones has a nearly constant compression ratio, so that only the surface contact areas between the crushed stones are crushed. It has a compression process of compressing with a limited compression force, and a crushing process of crushing and accumulating a layer of compressed crushed stone.

This is achieved by repeating the compression step and the crushing step a predetermined number of times to improve the surface of the crushed stones to a shape with fewer protrusions, and then discharging the crushed stones.

Furthermore, the present invention provides a device for improving the particle shape of crushed stone to achieve the above object, and includes a hollow drum horizontally installed with its center line inclined with respect to a horizontal plane, and a hollow drum that penetrates the hollow portion of the drum and has a center line extending from the center line of the drum. a rotatable roller having an axis offset from the
Means for adjusting the pressure on the crushed stone between the inner surface of the hollow drum and the roller surface, and a driving means for rotating the hollow drum, and means for supplying crushed stone to one end face side and the other end face side of the hollow drum, respectively. We propose a configuration in which a discharge means is arranged.

[For production]

In the above-mentioned structure, crushed stone supplied in a natural falling state is first piled up in an unconsolidated state, and the deposited layer is compressed within a compressive force range that does not cause internal fragmentation of the crushed stone to remove only the surface protrusions. Selective crushing is performed, and the resulting consolidated layer of crushed stone is allowed to fall naturally again, crushed, and deposited in an unconsolidated state. This is repeated a predetermined number of times to improve the crushed stone surface to a shape with fewer protrusions, and the crushed stone is discharged by the discharge means.

Therefore, grain shape can be improved efficiently, reliably, and easily using the most economical compression method.

Note that the above configuration of the present invention and its effects will be more clearly understood from the following description.

Figure 4 shows the value obtained by dividing the distance traveled by the compression surface by the initial thickness of the crushed stone (compression ratio) when crushed stone is placed between two compression surfaces located approximately parallel to each other and compressed. FIG. 2 is a diagram showing the relationship between the reaction force (compression force) and the reaction force (compression force) on the compression surface.

Curves 5 and 5 in the figure represent different types of crushed stone, and the curves differ depending on the compressive fracture strength and initial grain shape of the crushed stone, but they all have similar trends.

Crushed stones placed on a compressed surface in free fall contact each other with relatively few surface protrusions (corresponding to point A in the figure, see Figure 5). When compression is started, even if the reaction force on the compression surface is small, it easily becomes a large stress on the protrusions on the surface of the crushed stone, and the contact portion is crushed. As the density of crushed stone increases as compression progresses, the number of contact points also increases, and even if the stress that causes one crushed stone surface protrusion to fracture remains constant, the reaction force of the entire crushed stone layer increases, resulting in Approach point (B, , B2). As the compression continues and reaches the right side of point B, the resultant force acting on the contact point of the crushed stone reaches a sufficient magnitude to crush the inside of the crushed stone depending on the location, and internal crushing begins partially. be done. In this case, the rate of increase in the reaction force with respect to the increase in the compression ratio becomes more rapid than when the surface protrusions are crushed.

The present invention aims to carry out compression crushing under conditions that do not cause internal penetration of the crushed stone as much as possible and also effectively crush the surface protrusions, and the conditions are within a range not exceeding point B in Figure 1. This can be met by crushing with According to Figure 4, in order to carry out crushing under conditions near point B, there is a method of setting the compression ratio to 6 points (C□, C2) and a method of setting the compression force to point D (D, D2). There are possible ways. However, even if the compression surface is retreated from point B, the thickness of the crushed stone does not return to the original point A, and due to the elasticity of the crushed stone, E
It only stays at point (E, ,E,), and when that layer is compressed again without crushing, the reaction force increases rapidly, so it is difficult to control crushing by the compression ratio alone, and the compression It is easier to control the force directly. Nevertheless, in order to efficiently improve the grain shape, it is necessary to generate an almost uniform compression force over a wide range of the compression surface, and to do this, it is necessary to crush the compressed layer each time. It is necessary to compress the data at a substantially uniform compression ratio.

Therefore, in order to crush only the surface protrusions rather than the inside of crushed stones, first the crushed stones that have flown in free fall or similar conditions are piled up in an unconsolidated state, and a nearly uniform compressive force is applied to the layer. In order to generate crushed stone, the compressed stone is compressed at a nearly uniform compression ratio, and the compressive force is limited to a certain level using a hydraulic cylinder etc. to prevent crushing inside the crushed stone.The resulting compacted layer of crushed stone is then crushed again. This is carried out by allowing the particles to fall freely so as to make contact only with the surface protrusions, crushing and depositing them, and repeating this operation.

Incidentally, Table 1 shows an example of the effect of grain shape improvement according to the present invention, and the actual area ratio represents the degree of grain shape improvement. Conventionally, it was considered difficult to achieve an actual area ratio of 60 or more using a method that uses compression force, but according to the method of the present invention, compression force and number of compressions can be adjusted depending on the type of rock and particle size distribution. By making appropriate selections, it can always be 60 or more.

Note that Table 1 was conducted using crushed stone having a particle size distribution of 20 to 5 square meters. Therefore, after grain shape improvement, 5I
The percentage of crushed stone that maintained a particle size of II1 or more was defined as the yield.

If you are trying to improve the actual rate.

The yield decreases, although the degree varies depending on the conditions.

According to the method of the present invention, the compression force and the number of times of compression can be set according to the aggregate demand situation, and the most economical conditions can be selected in the combination of actual volume ratio and yield.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In the apparatus for improving the particle shape of crushed stone shown in FIGS. 1 and 2, a hollow drum 1 has a liner 2 attached therein, and a receiving roller 6
is rotatably supported. 4 is a rib provided on the outer periphery of the hollow drum 1. A chain wheel 5 is attached to the outer periphery of the hollow drum 1, and the hollow drum 1 is rotated by a drive motor 19 via a roller chain 21 that engages with the chain wheel 5. Note that the rotation of the hollow drum 1 is not limited to this, and may also be performed using, for example, a gear attached to the periphery of the hollow drum 1, a friction wheel, or the like. Further, both ends of the hollow drum 1 are open, and an ore feeding chute 9 is arranged at one open end side, and a large number of discharge ports 8 are bored along the curve of the hollow drum 1 at the other open end side. An ore discharge hopper 10 is arranged at the lower part of the outer periphery of the hollow drum 1 where the discharge port 8 is located.

The receiving roller 6 and the drive motor 19 are attached to a tilting frame 11.

The feed side of the ore chute 9 is lifted from the bed 12 by the tilting cylinder 13, making it possible to tilt the hollow drum 1 at a predetermined angle with respect to the horizontal plane. Further, a reduction roller 17 and a roller shaft 18 pass through the hollow part of the hollow drum 1, and slidable roller bearings 14 are attached to both ends of the roller shaft 18, and the roller shaft 18 is tilted via a bearing bracket 16. It is fixed to the frame 11.

Note that the roller bearing 14 can be pushed down by a reduction cylinder 15.

Next, a grain shape improvement method using the above device will be explained.

First, the hollow cylinder 1 is set so that its center line is inclined at a predetermined angle with respect to a horizontal plane. This operation is carried out by lifting the tilting frame 11 from the bed 12 by means of the tilting cylinder 13 and raising the feed side.

The crushed stone is supplied from one open end of the hollow drum 1 using the ore feed chute 9, and is discharged to the ore discharge hopper 10 from the discharge port 8 at the other open end. Here, the crushed stone supplied from the ore feed chute 9 is transferred to the liner 2 of the hollow drum 1.
It is compressed between the roller 17 and the reduction roller 17, and is subsequently lifted up by the rotation of the hollow drum 1, and then falls halfway and advances toward the discharge side. As the hollow drum 1 rotates in this manner, the crushed stone sandwiched between the liner 2 and the reduction roller 17 moves together with the liner 2, and as the crushed stone moves, the reduction roller 17 and the roller shaft 18 also rotate.

Here, by appropriately selecting the rotational speed of the hollow drum 1, the locus of crushed stones in the hollow drum 1 can be made as shown in FIG. 3. In addition, in FIG. 3, a is a compression zone, b is a lifting zone, C is a falling zone, and d is a deposition zone.

The supplied crushed stone falls into the hollow drum 1 and is deposited in the deposition zone d), moves with the rotation of the hollow drum 1, and is compressed between the hollow drum 1 and the reduction roller 17 (compression zone a). The compressed crushed stone is lifted while being pressed against the inner surface of the hollow drum 1 by the centrifugal force caused by the rotation of the hollow drum 1 (lifting zone b), and the point at which the effect of gravity becomes greater than the effect of the centrifugal force is reached. hollow drum 1
Fall zone C), hollow drum 1, which is released from the inner surface and falls in a parabola while being regulated by the initial conditions at that point.
It collides with the inner surface or the surface of the reduction roller 17, or collides with crushed stones that have already been deposited.

Eventually it is deposited in an unconsolidated state (deposition zone d
). The accumulated crushed stone is moved by the rotation of the hollow drum 1 to a reduction roller 17 whose axis is below the center line of the drum 1.
and is compressed again.

The method and apparatus for improving the particle shape of crushed stone according to the present invention are generally configured as described above.

In addition, if the apparatus of the above embodiment is used, the inner surface of the hollow drum 1 and the surface of the reduction roller 17 reduce the mutual distance by rotation, and constitute a crushing mechanism that performs compression crushing, and its operation is also such that the crushing stone is free. By falling and accumulating in an unconsolidated state, by tilting the center line of the hollow drum 1 with respect to the horizontal plane, the crushed stone gradually moves from the ore feed chute 9 side to the discharge port 8 side, and the center of the hollow drum 1 By changing the slope of the line according to the amount of ore supplied, it is possible to control the thickness of the crushed stone sediment layer almost uniformly.

At this time, if the center line of the hollow drum 1 and the axis of the roll-down roller 17 are maintained almost parallel, the compression ratio in each part of the hollow drum 1 will be approximately equal. The compressed stone is lifted by the hollow drum 1 and begins to fall, but the layer of crushed stone is Because the speeds are different, the falling trajectories are different, and they collide at different positions,
The crushed stone is crushed and, therefore, its particle shape is improved while it moves from the ore feed chute 9 side to the discharge port 8 side.Therefore, it is suitable as an apparatus for carrying out the method of the present invention. be. However, the present invention is not limited to this embodiment, and can be modified within a range that can achieve the intended purpose of the present invention.

Incidentally, for example, in a show crusher or a cone crusher where the compression surface swings, the slope of the swinging surface is set to a value close to the angle of repose of the crushed stone, and the swinging compression surface at the bottom dead center of the swinging,
The compression ratio can be kept almost constant by making the three surfaces, the surface formed by the angle of repose of the accumulated crushed stone and the upper compression surface corresponding to the oscillation compression surface, pass through the center of oscillation. I can do it. Furthermore, the compressed surface is supported by a hydraulic cylinder, etc. to limit the compressive force, and the vertical component of the rocking acceleration is made to be greater than the gravity, thereby crushing the compressed layer of crushed stone.
It can be deposited on a rocking compression surface in free fall or in flight impact. In addition, 5 pieces of crushed stone are placed in a constant layer thickness between a compression surface where each part vibrates almost in the same way due to eccentric drive or rotation of an eccentric load, and a corresponding compression surface located parallel to that surface. This can also be carried out by transporting at a constant speed, supporting the compressed surface with a hydraulic cylinder, etc., and making the vertical component of the acceleration of vibration greater than the force of gravity.

[Effects of the Invention] As is clear from the above explanation, the present invention has the following effects.

In the invention of a method for improving the particle shape of crushed stone, the particle shape of crushed stone can be efficiently, reliably, and easily improved using the most economical compression method, and the crushed stone with improved particle shape can be used in concrete. Increase the strength of concrete by using it as aggregate.

The amount of cement used can be reduced.

In the invention of the apparatus for improving the particle shape of crushed stone, the above method can be carried out efficiently by the combination of the configurations set forth in claim 2.

[Brief explanation of drawings]

Fig. 1 is a side view showing a part of the apparatus for improving the particle shape of crushed stone according to the present invention in cross section, Fig. 2 is a partial sectional view taken along the nn arrow in Fig. 1, and Fig. 3 is a hollow view of the crushed stone. FIG. 4 is a diagram showing the relationship between the compression ratio and compression force, and FIG. 5 is a diagram showing the state in which crushed stone to be improved in grain shape is piled up without being compressed. 1... Hollow drum 2... Liner 3... Tire 4... Rib 5... Chain wheel 6... Receptacle Roller 7... Thrust receiving roller 8...
Discharge port 9...Ore feed chute 11...Tilt frame 13...Tilt cylinder 15...Reduction cylinder 17...Reduction roller 19... ... Drive motor 21 ... Roller chain 10 ... Ore discharge hopper 12 ... Bed 14 ... Roller bearing 16 ... Bearing bracket 1-8 ... Roller Shaft 20... Drive chain wheel...=shi, 7

Claims (2)

[Claims] (1) A supply step of supplying crushed stone between two facing compression surfaces and compressing it by reducing the distance between the compression surfaces, supplying and depositing the crushed stone in a free-falling or flying state; , a compression process in which a layer of accumulated crushed stones is compressed by moving the compression surface so that each part of the layer has a nearly constant compression ratio, and compressing with a limited compression force so that only the surface contact areas between the crushed stones are crushed; a crushing step of crushing and depositing a layer of crushed stone;
A method for improving the particle shape of crushed stone, characterized in that the compression step and the crushing step are repeated a predetermined number of times to improve the surface of the crushed stone to a shape with fewer protrusions, and then the crushed stone is discharged. (2) a hollow drum horizontally installed with its center line inclined with respect to a horizontal plane; a rotatable roller passing through the hollow portion of the drum and having an axis deviated from the center line of the drum; and an inner surface of the hollow drum. and a drive means for rotating the hollow drum, and a means for supplying crushed stone and a means for discharging crushed stone on one end face side and the other end face side of the hollow drum, respectively. A device for improving the particle shape of crushed stone.