JPH0214753A - Improvement of grain shape - Google Patents

Abstract

PURPOSE:To obtain a roundish grain shape by releasing stock to be crushed in a rotor for release in the peripheral direction by centrifugal force applied by the rotor rotating at a high speed and by receiving the released stock in a rotor for repulsion to form a deposited bed. CONSTITUTION:Stock charged from the feed hole 15 of a hopper 16 enters a rotor 21 for release through a lower hopper 17, the rotor 21 is rotated to capture the stock by the perpendicular wall 31 and the stock is released in the peripheral direction through a release path 33 by centrifugal force. The released stock enters the recess 11 of a rotor 5 for repulsion rotating in the same direction as the rotor 21 for release and deposits successively by centrifugal force applied by the rotor 5 to form a stock deposited bed 34 in the rotor 5. After the bed 34 is formed, released stock collides against the rotating bed 34, so the corners to the stock are rubbed off and a roundish grain shape is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for improving the crushed material, such as crushed stone, which has been secondarily crushed by a cone crusher or the like, into a rounded particle shape similar to that of natural aggregate. be.

[Prior Art] Artificial aggregate for civil engineering and construction is generally a crushed product obtained by first crushing rocks using a show crusher and then secondly crushing them using a lawn crusher. has a department.

When the above-mentioned crushed product is used as aggregate for concrete, the strength of the concrete is lower than that of the original natural aggregate due to the influence of its particle shape, and therefore, more cement is required to achieve the same strength. However, in recent years, there has been a desire for something with a roundness similar to that of natural aggregate.

An example of a method for adjusting the particle shape of the crushed product is disclosed in Japanese Patent Publication No. 53-33785.

In FIG. 3, a discharge rotor q is provided in a housing d consisting of a bottom plate a, a vertical wall, and an upper disk C, and rotates via a rotation shaft f supported by a bearing e.
is rotated at high speed by a drive motor h.

Therefore, the material to be crushed (hereinafter referred to as raw material) fed into the rotor q by the material to be crushed supply device i provided at the upper center of the rotor is moved by centrifugal force through a discharge path consisting of blades (not shown). Then, it is ejected from the rotor 9 in a horizontal direction. The discharged raw material is deposited in the housing d,
A dead stock j is formed from the raw material at a predetermined angle of repose.

After that, the ejected raw material collides with the dead stock surface formed with an inclination, and the raw material is sized (grain shape correction).
is carried out. The sized particles are discharged outside the machine through a discharge locator.

[Problems to be Solved by the Invention] However, according to the above method, the pile collision surface made of the piled raw materials forms a certain slope, and a grinding effect that is effective for crushing and improving grain shape cannot be obtained. do not have.

Furthermore, the rotor discharges the raw material at a high speed, so that
High speed rotation is required, which causes problems such as mechanical imaging, damage to the rotor tip, and increased power.

Therefore, an object of the present invention is to provide a method that reduces the mechanical imaging and the like, increases the number of collisions of raw materials, and improves the grain shape to have a rounded shape similar to that of -layer natural aggregate.

[Means for Solving the Problem] In order to achieve the above object, the grain shape improving method of the present invention includes the following steps:
A centrifugal force is applied to the material to be crushed, which is introduced from the upper center of the center, through the high-speed rotating discharge port to the outer circumferential direction, and the material to be crushed is concentrically placed outside the discharge rotor at an appropriate interval. The material to be crushed is housed in a repulsion rotor with a concave cross section, and a centrifugal force of 0.5 to 3 G is applied to the crushed material by the rotation of the repulsion rotor to form a deposition bed within the concave cross section. , the particles to be crushed connected to the pile bed are made to collide with each other to improve the grain shape.

[Operation] Raw materials are introduced from the top center of the high-speed rotating discharge rotor.

The input raw material is given centrifugal force by the discharge rotor and is discharged in the outer circumferential direction.

The discharged raw material enters the concave cross-section of the repulsion rotor.

The raw material is deposited and filled in the concave cross-section by a centrifugal force of 0.5 to 3 G due to the rotation of the repulsion rotor, and a bed of the raw material is formed, the inner surface of which is a substantially vertical surface.

Next, the following raw material collides with the inner surface of the deposition bed, and this causes the corners of the raw material to be dropped and the grain shape is improved, and the raw material after the collision is temporarily attached by the centrifugal force caused by the rotation of the repulsion rotor. Since it moves together with the repulsion rotor while maintaining its condition, it collides with the following raw material again, and the grain shape of the layer is improved.

Further, by setting the centrifugal force acting on the raw material to 0.5 to 3 G, the deposition bed is relatively soft, and the collision of the raw materials replaces the raw materials in the deposition bed.

[Example code] Embodiments of the present invention will be described based on the accompanying drawings.

In FIGS. 1 and 2, 1 is a housing placed on a pedestal 2 and has an upper open port 3 and a lower discharge port 4, and 5 is a rotatable repulsion rotor disposed at the top of the housing 1. It is.

The repulsion rotor 5 has a concave cross section 11 in which an upper disk 7 having an opening 6, a vertical cylindrical wall 8, and a lower disk 10 having an opening 9 are integrally formed, and is mounted on a support roller device on a pedestal 2, that is, It is supported by a lower roller 12 and side rollers 13.

A cylindrical frame 14 is provided in the upper opening 6 of the repulsion rotor 5.
is provided with an upper hopper 16 having a supply port 15 therein.
is attached, and a lower hopper 17 is attached roughly below it. A pulley 18 is attached to the outside of the cylindrical frame 14, and a repulsion rotor motor 20 is connected via a belt 19.
connected to. The lower opening 9 of the repulsion rotor 5 and the opening 3 of the housing 1 communicate with each other.

Reference numeral 21 denotes a discharge rotor disposed concentrically within the repulsion rotor 5 at an appropriate interval, and this rotor is rotatably fitted in a bearing 22 disposed at the center of the housing 1.
A pulley 24 is attached to the lower end of the rotating shaft.
is attached, and the discharge rotor seventh rotor 2 is connected via the belt 25.
It is connected to 6.

The discharge rotor 21 has an upper disk 2B having a central opening 27 and a lower disk 29 which are integrated through a vertical wall 30.31° 32, and the discharge path 33 is formed by the vertical wall 30.31.
(three passages in the illustrated example), and the lower end of the lower hopper 17 is located close to the central opening 27 of the upper disk 28.

Next, to explain the operation of the embodiment, the raw material input from the supply port 15 of the upper hopper 16 enters the discharge rotor 21 via the lower hopper 17, and is captured by the vertical wall 31 due to the rotation of the rotor 21. Centrifugal force is applied to discharge path 3
After 3, he is thrown outward.

The thrown raw material enters the recess 11 of the repulsion rotor 5 which is rotating in the same direction as the discharge rotor 21, and is successively deposited by the centrifugal force caused by the rotation of the repulsion rotor. In other words, it is deposited up to the edge of the opening 9 of the lower disk 10 to form a deposition bed 34 on the rotor 5.

The inner surface 35 of the formed deposition bed 34 becomes a substantially vertical surface.

The raw material accumulation bed 34 is formed by the centrifugal force acting on the raw material due to the rotation of the repulsion rotor 5 and the layered action of the lower disk 10. Therefore, the rotation of the rotor 5 is caused by the rotation of the raw material. The speed is set close to the critical speed that temporarily maintains the adhered deposition state. The centrifugal force due to the rotation cannot be uniquely determined depending on the diameter of the repulsion rotor and the properties of the raw material, but it may be within the range of approximately 0.5 to 3G. 0
．． If the pressure is less than 5G, the falling edge due to the weight of the raw material will overcome the adhesion force due to centrifugal force, so the inner surface of the deposition bed will not be approximately vertical.On the other hand, if it is more than 3G, a vertical surface will definitely be formed. The adhesion forces become large, resulting in a strong sediment bed, impairing the replacement of raw materials.

Thus, by determining the centrifugal force as described above, after the raw material accumulation bed 34 is formed as if a ring liner was attached to a constant thickness, the raw material that is subsequently discharged rotates in the same direction as the raw material discharge direction. As a result of this collision, the angular corners of the raw material are removed and the raw material becomes rounded into grains.

In addition, the raw material that has collided with the accumulating bed moves along the inner surface 35 of the accumulating bed 34 of the repulsion rotor 5 while maintaining the - time adhesion state, so that it does not collide again with the encroaching raw material. This process is repeated many times to further improve grain shape.

In addition, since the deposition bed maintains the required adhesion force due to the centrifugal force generated by the rotation of the repulsion rotor 5, there is little reduction in the impact force caused by the collision of discharged raw materials, and the cough bed 34 Collision between the raw material and the released raw material causes displacement of both raw materials.

As described above, the scraped raw material falls under its own weight, passes through the housing 1 through the opening 9, and is discharged from the discharge port 4.

In addition, since the inner surface 35 of the deposition bed 34, that is, the collision surface, is almost vertical and the thickness with the vertical wall 8 is constant,
Since there is almost no wear on the vertical wall 8 and almost no collision of the rebounded raw material against the top disk 7, there is also very little wear on the top disk 7.

Furthermore, when the repulsion rotor 5 is stopped, the centrifugal force on the sedimentation bed disappears, so the formed vertical surface breaks and falls down to become an inclined surface, and on the other hand, when the repulsion rotor 5 is started, it accumulates again and becomes a vertical surface.
During this time, the raw material in the deposition bed is replaced, and the crushing effect can be enhanced.

Furthermore, in the embodiment described above, the repulsion rotor 5 rotates in the same direction as the discharge rotor 21, but it may rotate in the opposite direction.

Further, although the present invention does not aim at aggressive crushing, it goes without saying that flat raw materials can be crushed into small pieces.

[Effects of the Invention] As described above, the present invention accommodates the discharged materials to be crushed in the repulsion rotor, which is concentrically provided at appropriate intervals outside the discharge rotor and has a concave cross section. Since a centrifugal force of 0.5 to 3 G is applied to the object to be crushed by the rotation of the repulsion rotor to form a pile bed within the concave cross-section, the angular corners of the object to be crushed are reliably removed and extremely rounded particles are formed. It is possible to obtain aggregate for concrete with a high degree of shape improvement, and at the same time, since the inner surface of the accumulation bed is substantially vertical, there is little scattering of raw materials and extremely little wear on the repulsion rotor.

Furthermore, by rotating the repulsion rotor, the rotational speed of the discharge rotor can be reduced to approximately 2/3 of that of a conventional deposition rotor that stops the deposition bed, which reduces mechanical vibration. Wear of members and power consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the apparatus according to the grain shape improvement method of the present invention, FIG. 2 is a cross-sectional view of knee I in FIG. 1, and FIG. 3 is a longitudinal cross-sectional view showing a conventional example. is.

Claims (1)

[Claims] A discharge rotor that rotates at high speed applies centrifugal force to the material to be crushed, which is introduced from the upper center, and releases it in the outer circumferential direction. The material to be crushed is housed in a repulsion rotor with a concave cross section, and a centrifugal force of 0.5 to 3 G is applied to the crushed object by the rotation of the repulsion rotor to form a deposition bed within the concave cross section. . A method for improving grain shape, characterized in that the grain shape is improved by colliding the subsequent crushed material with the pile bed.