JPH0317540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vertical pulverizer that pulverizes cement raw materials, coal, chemicals, etc. through cooperation between a rotary table and rollers.

[Prior art]

BACKGROUND ART A vertical crusher equipped with a rotary table and rollers is widely used as a type of crusher for finely crushing granules such as cement raw materials, coal, and chemicals into powder. This type of crusher consists of a disk-shaped rotary table that is driven by a motor with a reducer to rotate at low speed in the lower part of a cylindrical casing, and a part that divides the outer circumference of the upper surface into equal parts in the circumferential direction, which is pressed by hydraulic pressure or the like. It is equipped with a plurality of rollers that are driven to rotate. The granules as raw materials supplied to the center of the rotary table through the supply pipe are subjected to centrifugal force in the radial direction of the table due to the rotation of the table, and as they slide on the table, they receive a force in the rotational direction from the table. The table rotates somewhat slower than the table rotation speed. The above two forces, ie, the radial and rotational forces, are combined, and the powder moves to the outer periphery of the rotary table while drawing a spiral trajectory on the table. Since a roller is pressed into contact with this outer periphery and rotates, the particles with spiral lines enter between the roller and the rotary table from a direction forming a certain angle with the roller axis direction, and are bitten and crushed. Ru. On the other hand, hot air is guided to the base of the casing by a duct, and as this hot air blows up from the annular space between the outer circumferential surface of the rotary table and the inner circumferential surface of the casing, the fine powder is dried. It rises inside the casing, and is discharged from the outlet as a mixture with hot air and sent to the next process.

FIG. 1 is a plan view of a rotary table for explaining in what proportion the supplied granules go to the rollers in a conventional crusher in which granules are supplied to the center of the rotary table through a supply pipe. In the figure, reference numeral 1 indicates a rotary table rotating in the direction shown by arrow A in the figure, and reference numeral 2 indicates four rollers that are in line contact with the upper surface of the rotary table 1. As mentioned above, as a result of centrifugal force acting in the radial direction due to the rotation of the rotary table 1, the granules receive a force outward, and also receive a force in the direction of rotation due to the rotation of the table 1, and the granules attempts to move in the direction that is the result of the two forces. Furthermore, when the table rotation speed is constant (that is, the table angular velocity is constant), the centrifugal force differs depending on the position (radial distance) of the placed particles, so this combined direction also changes every moment. for example,
If particles are dropped at 10 points on the radius of table 1 in Fig. 1, the radius at two or three points near the center is small, so the static friction force acting on the table and particles is greater than the centrifugal force. There is no relative movement between the table and the grains, and they just rotate around together with the table, but the remaining 7 to 8 points each move spirally toward the outer periphery, tracing trajectories as shown by the dotted lines in the figure. do.
Note that the trajectory of the particles shown in the figure changes depending on parameter variables such as the table diameter, the table rotation speed, the coefficient of dynamic friction between the particles to be dropped and the table, and the falling position (radius and angle of the falling position). Needless to say. The trajectory in FIG. 1 shows an example where coal stone particles are dropped by a vertical crusher that is conventionally manufactured and sold on a commercial basis.

In addition, in Figure 2, Figure 1 shows the falling position of the particles r _i
= (0.05 to 0.5) R, φ _i = 0° for only 10 points in a row, r _i = (0.05 to 0.5) R, φ _i = 0°, 10°, 20°, ...8
The trajectory of the grain is shown when 90 points at 0° are drawn.

As is clear from FIG. 2, in the conventional crusher, among the particles falling at the 10 points, those closest to the center are bitten by the first roller 2 that they encountered, or pass through the inside of the roller 2, and the second one is crushed. The particles may be bitten by the third roller 2, but the particles falling at a position away from the center are not bitten by the roller 2, but come off the periphery of the rotary table 1 and fall outside the table. As mentioned above, the fallen particles are lifted up by the hot air that blows up the annular space between the rotary table 1 and the casing, and are returned directly onto the rotary table 1, or are classified by the upper separator and placed on the rotary table. However, the air volume and wind pressure loss consumed for blowing up and circulating the particles become a problem. In other words, since the granules overflowing from the rotary table 1 are granules before being crushed, they are usually coarse particles with a diameter of 30 to 50 mm.
Requires wind speed on the order of m/s. On the other hand, considering the degree of pulverization of the raw material and the degree of classification of the separator, 300 μm, which is twice the maximum particle size of 150 to 200μ, is sent to the inlet of the separator.
It is meaningless for particles with a diameter of ~400μ or more to reach the target, and even considering the difficulty of classification on the rotary table 1, it is sufficient to blow up particles with a diameter of 2mmmm, which is 10 times the maximum particle size of 200μ. The wind speed required for this is
A speed of about 20 to 30 m/s is sufficient.

In this way, conventional crushers require air blowing equipment with an air volume several times the required air volume in order to blow up and circulate the overflow granules, and the increased circulation volume requires large air volume and wind pressure. This method not only significantly increases equipment cost and power consumption, but also has the drawback that the granules returning from the separator do not return to the rotary table and repeat a flow unrelated to crushing, consuming wasted energy. .

[Summary of the invention]

The present invention has been made in view of the above points, and consists of branching the raw material supply pipe into the same number of crushing rollers above the center of the rotary table, and connecting the discharge ports of these branched pipes to adjacent ones of the plurality of crushing rollers. The upper surface of the rotary table between the two crushing rollers is located close to the center of the rotary table, and is opened only in the vicinity of the starting point of the trajectory that contacts the crushing rollers out of the trajectory drawn by the rotary table as it slides outward. rate approximately
We have eliminated as much as possible the overflow of large-grain raw stone (raw material granules that have never been crushed by rollers) from the table, which has been left unattended since 100%, and the machine casing is placed above the rotary table. By constricting and forming a drum shape, it is possible to add an inward component to the rising airflow, improving the rate at which coarse particles fall to the center of the table, and reducing the air volume and pressure required for blowing up, thereby reducing the power of the blower. To provide a vertical crusher that significantly reduces the amount of waste, etc., improves crushing efficiency by improving crushing probability, and eliminates wasteful transportation energy such as overflow of green stone and circulation of coarse particles above the rotary table. It is something. Embodiments of the present invention will be described in detail below with reference to the drawings.

[Example] Fig. 3 and Fig. 4 show an example of the vertical crusher according to the present invention, Fig. 3 is a longitudinal cross-sectional view thereof, and Fig. 4 is an arrangement of a rotary table, a grinding roller, and a raw material supply pipe. FIG. In the figure, the crusher 11
is equipped with a casing 12 that houses the entire crushing unit such as a rotary table 15, which will be described later, and stands upright on the floor.The lower half of the casing 12 is formed into a cylindrical shape, and a motor with a speed reducer is installed in the center of the casing 12. 13 is fixed. Further, the upper half of the casing 12 is formed into an hourglass-shaped cylinder with a circular cross section by being drawn at the center in the height direction. An inclined wall 12a having a truncated conical shape is formed. A rotary table 15 formed in a disc shape and having a liner 14 adhered to its horizontal upper surface is attached to the rotating shaft facing upward of the motor 13.
It rotates horizontally at low speed in the direction shown by arrow B in the figure. Reference numeral 16 denotes four arm shafts that are horizontally supported by the casing 12 in close proximity to the outside of a portion that divides the peripheral edge of the rotary table 15 into four equal parts in the circumferential direction. An L-shaped arm 17 is rotatably mounted on the arm shaft 16, and a crushing roller 19 having a truncated conical shape is mounted on a roller shaft 18 that is fixedly supported by its bearing. Each of them is rotatably mounted on a shaft, and its peripheral surface is brought into contact with the upper surface of the outer peripheral portion of the rotary table 15. The operating end of a pressure cylinder (not shown) that is pivotally supported on the casing 12 side is pivotally connected to each arm 17. By operating this pressure cylinder, the arm 17 swings and the roller 19 is moved toward the rotary table 15. The pressing force of the rotary table 1 changes.
5 and rollers 19 so that the crushing force for the object to be crushed is adjusted. Note that the roller 19 and the rotary table 15 are in line contact (actually, a surface contact with a very small width), and in FIG. 4, this contact line is indicated by the reference numeral 19a. An annular air passage 20 is provided below the outer periphery of the rotary table 15 and is connected to a hot air generator through a duct (not shown). , an annular blow-up passage 21 is provided that communicates the air passage 20 with the inner chamber of the casing 12. Also,
An annular armor ring 12b is attached to the inner circumferential surface of the inclined wall 12a facing the blowing passage 21 to rectify the blowing hot air.

On the other hand, at the upper end flange of the casing 12,
An upper casing 22 formed in a cylindrical shape is joined to the upper casing 22, and a bearing 23 including a pair of upper and lower ball bearings is fixed to the upper end of the upper casing 22. A separator designated by the reference numeral 24 is a separator for classifying the pulverized material rising by the hot air blown up from the blow-up passage 21, and is pivotally supported by the bearing 23 and located at the center of the upper casing 22 and the upper inclined wall of the casing 12. It is formed of a cylindrical body 24a that hangs down from the upper end of the cylindrical body 24a, and a plurality of tilting rotary blades 24d that are supported by supporting members 24b and 24c at the center and lower ends of the cylindrical body 24a, and are pivoted to the upper end of the cylindrical body 24a. The pulled pulley 25 is drivingly connected to a pulley 27 of a motor 26 by a belt 28. Reference numeral 29 denotes a discharge port which is connected to the next step (not shown) through a duct and discharges the pulverized material.

A feeder 30 connected to a raw material hopper (not shown) is installed horizontally above the upper casing 22, and a conveyor 31 for conveying the loaded raw material is stretched inside the feeder 30. A main pipe 32a of the raw material supply pipe 32 is connected to the downward flange portion of the feeder 30, and extends through the cylindrical body 24a of the separator 24 and hangs down concentrically therewith. The main pipe 32a is formed in a cylindrical shape, and four branch pipes 32b, 32c, 32d, and 32e, the same number as the rollers 19, are branched from the lower end thereof. Each of the branch pipes 32b to 32e is inclined so that the distance between them becomes wider toward the lower end, and the branch pipes 32b to 32e are arranged close to the upper surface of the rotary table 15 at a position near the center of the rotary table 15 between adjacent rollers 19. The outlet of each branch pipe 32b to 32e is open. Therefore, the raw material falling down the main pipe 32a passes through the branch pipes 32b to 32e and is distributed and supplied to four locations on the rotary table 15 from the openings thereof.

The operation of the pulverizer configured as above will be explained using coal pulverization as an example. After starting the motors 13 and 26, when granular coal is fed into the raw material hopper as a raw material, the coal is conveyed by the conveyor 31 of the feeder 30 and falls from the conveyance terminal end into the main pipe 32a of the raw material supply pipe 32. After that, each branch pipe 3
It is divided into 2b to 32e and distributed and supplied to four locations on the rotary table 15. At this time, the rotary table 15 is driven by the motor 13 and rotates horizontally, and the roller 19 is also pressed against the rotary table 15 and rotates as a result, so the fallen granular coal is
It slides on the table 15 in response to the centrifugal force caused by the rotation of the rotary table 15, and at the same time receives a force in the rotational direction from the rotary table 15, slides between it and the table 15, and rotates somewhat slower than the table rotation speed, which will be described later. It moves to the outer periphery of the rotary table 15 while drawing a spiral trajectory. Most of the moved granular coal is caught between the rotary table 15 and the rollers 9, and is crushed into pulverized coal by compression, impact, and shearing action. Further, the pulverized coal that has been bitten by the roller 19 or a part of the granular coal that has not been bitten by the roller 19 for some reason is transferred to the rotary table 15.
tries to fall off the periphery. At this time, hot air sent through the air duct and air passage 20 is blown up from the blow-up passage 21 between the rotary table 15 and the casing 12 while being rectified by the armor ring 12b, so that the crushed fine powder that has overflowed. The charcoal and the granular charcoal are connected to the passage 21
It is blown up by hot air in the vicinity of , and sent into the sparator 24 on the updraft. Since the separator 24 is driven and rotated by the motor 26, centrifugal force is applied to the particles by the swirling airflow generated by the rotation of the rotating blades 24d, and coarse granular coal is blown outward and rotated. After falling onto the table 15, pulverization is repeated until it becomes a fine powder with the required particle size. Further, the pulverized coal having a particle size below the required particle size passes through the separator 24 and is discharged from the discharge port 29 together with hot air, and is recovered after being conveyed through the duct to the next process, such as a fuel system or a dust collector.

Therefore, the behavior of the object to be crushed on the rotary table 15 will be explained. FIG. 5 shows the behavior of granules on the rotary table 1 in a conventional pulverizer, corresponding to FIG. FIG. 3 is a plan view for explaining how much of the particles passing through encounters the roller 2; As is clear from the figure, only the particles passing between points P ₁ and P ₂ encounter the roller 2, but all of the particles closer to the outer circumference and some of the particles closer to the inner circumference All of them deviate from the rotary table 1. On the other hand, FIG. 6 shows the behavior of the grains in the device shown in FIG. 4, corresponding to _{FIG .} The branch pipes 32b to 32e of the raw material supply pipe 32 are opened between the rollers and the granules are supplied thereto, and almost all of the granules encounter the rollers 19.

Next, among the raw materials that overflow from the rotary table 15 and are blown back by the updraft, coarse particles that do not reach the final product are crushed along the inner wall of the casing in a conventional crusher in which the casing 12 is cylindrical. A large amount of energy was lost due to the vertical reciprocating motion, but in this device, by drawing the casing 12 into an hourglass shape, the coarse particles are given an inward component from the time they pass through the blow-up passage 21. Since the coarse particles rise toward the center of the casing 12 along the inclined wall 21a, the probability of falling to the center of the rotary table 15 increases significantly, and the vertical reciprocating movement of the coarse particles is drastically reduced. Furthermore, the granular coal struck by the rotating blades 24d of the separator 24 falls along the inner circumferential surface of the casing 12, but since the casing 12 at this point is also narrowed down to a smaller diameter, By falling along this slope, most of the particles fall to the center of the rotary table 15, and the above-mentioned up and down reciprocating movement disappears. Even if some circulation occurs due to reciprocating motion, it is a circulation of relatively small particles excluding coarse particles that fall parabolically onto the rotary table 15 due to gravity overcoming the force of the airflow. Loss is extremely small.

In this embodiment, an example is shown in which four rollers 19 and four branch pipes 32b to 32e are provided, but two
Any number is acceptable as long as it is greater than or equal to 1. Further, in this embodiment, an example was shown in which the raw material supply pipe 32 was penetrating and hanging down inside the separator 24, but for example, the raw material supply pipe 32
2 may be passed through the upper casing 22 in an inclined manner from the side of the body to face above the center of the rotary table 15, and then branched into a plurality of branch pipes.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, in a vertical crusher, the raw material supply pipes are branched into the same number of crushing rollers above the center of the rotary table, and are distributed upward toward the center of the rotary table between adjacent crushing rollers. By opening the opening and selecting an appropriate position calculated backwards from the particle trajectory as the particle falling position at the opening,
Almost all of the particles that pass through the raw material supply pipe, pass through each branch pipe, and fall from the opening position reach the crushing rollers and are crushed, and then reach the outer periphery of the rotary table. Therefore, the amount of so-called green stone that overflows without being bitten by the rollers is drastically reduced, and the gas flow velocity and air volume required for blowing up the green stone can be significantly reduced.

Furthermore, by drawing the casing in the middle and forming it into an hourglass shape, the coarse particles blown up by the rising air are given an inward component toward the center of the casing by the inclined walls of the casing, and are directed toward the center of the rotary table. The probability of the coarse particles falling down after classification is greatly increased, and the probability that the coarse particles fall down to the center of the rotary table along the sloped wall where the diameter becomes smaller downwards is greatly increased. The wasteful circulation of reciprocating movements is drastically reduced. Therefore, together with the drastic reduction in the amount of overflowing raw rock, the wind pressure and volume of the blower can be significantly reduced, and as a result, the power of the blower can be reduced, and running costs can be expected to be significantly reduced. Equipment costs can be reduced. In addition, regarding the rotational power of the crusher table, it is possible to eliminate invalid work from the granule transport work that forms part of the crushing work, and as a result of reducing the crushing power per unit production amount, the crushing efficiency is improved. Running costs are reduced.

[Brief explanation of the drawing]

Figures 1, 2, and 5 are plan views of the rotary table for explaining the behavior of particles on the rotary table in a conventional vertical crusher. A plan view showing the movement trajectory of the raw material supplied to 10 points, Figure 2 shows the feeding of the raw material at an angle
Figure 5 is a plan view showing the locus of movement of the raw materials over a range of 90°, and the raw materials are dropped in a line with a pitch of 0.05R in a radius that bisects the space between adjacent rollers. FIG. 3, FIG. 4, and FIG. 6 show an embodiment of the vertical crusher according to the present invention, and FIG. 3 is a longitudinal cross-sectional view thereof.
FIG. 4 is a schematic plan view showing the relationship between the rotary table, the rollers, and the raw material supply branch pipe, and FIG. 6 is a plan view of the rotary table for explaining the behavior of the raw material on the rotary table. 11...Crusher, 12...Casing, 12a
... Inclined wall, 15 ... Rotating table, 19 ... Roller, 32 ... Raw material supply pipe, 32a ... Main pipe, 3
2b, 32c, 32d, 32e... branch pipes.

Claims (1)

[Claims] 1 Above the center of a rotary table that rotates with a plurality of crushing rollers in pressure contact with the upper surface of its outer circumference, raw material supply pipes are branched into the same number as the crushing rollers, and the discharge ports of these branch pipes are connected to adjacent ones of the crushing rollers. The upper surface of the rotary table between the two crushing rollers near the center, and the starting point of the trajectory of the granules falling onto the rotary table as they slide outward from the rotary table, where the trajectory comes into contact with the crushing roller. The cylindrical casing is concentric with the rotary table that houses the entire crushing device, and the cylindrical casing is concentric with the rotary table that houses the entire crushing device. A vertical crusher characterized by being shaped into a shape.