JPH0857331A - Vertical crushing mill - Google Patents

Abstract

PURPOSE: To reduce the crushing power by feeding optimum crushed coal of pulverized coal content to a combustion furnace by reducing the quantity of raw coal to be crushed by a roller (the quantity of raw coal falling onto a table). CONSTITUTION: Since when raw coal falling from a coal feeding pipe 2 comes into collision with a conical raw coal distributing plate 13 and is distributed and falls toward a table 1, fine coal in the raw coal is blown up by transporting air 6 and pneumatically transported upwards, fine coal content in crushed coal discharged form an outlet pipe 10 is restrained to about that in the raw coal 3 plus 3% to feed optimum crushed coal of pulverized coal content to a combustion furnace (a PFBC(pressurized fluidized bed combustion) boiler). Therefore, the quantity of raw coal to be crushed by a roller 4 (the quantity of raw coal falling onto the table) is lessened to reduce crushing power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical mill for coarse grinding.

[0002]

2. Description of the Related Art A conventional vertical mill for coarse crushing will be described with reference to FIG. 12, in which 1 is a table which is rotationally driven by a motor (not shown), and 2 is a coal feeding pipe hanging above the center of the table 1. 3 is raw coal, 4 is a roller which rotates in contact with the table 1, 5 is crushed coal, 6 is conveying air, 7 is a mill mill casing, 8 is a support plate attached to the lower part of the coal feeding pipe 2, Reference numeral 11 is a fixed type classification blade whose one end is supported by the support plate 8, 9 is a deflector plate fixed to the inner wall surface of the mill casing 7 around the table 1, and 10 is a side of the mill casing 7 surrounding the coal feeding pipe 2. Is the outlet pipe of.

In the vertical mill for coarse grinding shown in FIG.
The raw coal 3 is supplied from the coal feeding pipe 2 to the central part of the table 1 which is rotationally driven, and on the table 1, it is blown to the outer peripheral side of the table 1 by centrifugal force and is caught between the roller 4 and It is crushed into crushed charcoal 5. The crushed coal 5 is blown up into the inside of the mill casing 7 by the conveying air 6 blown up from the lower side of the mill and rises, and the extremely coarse coal in the crushed coal 5 collides with the fixed classification blade 11 and is cut. The pulverized coal 5 that has passed through the fixed type classification blade 11 is the outlet pipe 1
0 to a combustion furnace (PFBC (pressurized fluidized bed) boiler) (not shown) through a transport pipe (not shown), where it is burned, and the combustion gas is further subjected to a dust filter (not shown). Etc., and is sent to a gas turbine (not shown) for reuse.

At this time, the conveying air 6 blown up from below the mill by the flow diverter plate 9 located around the table 1.
Is deflected, the crushed coal 5 is inertially classified, and the coarse particles are returned to the central portion of the table 1 to be crushed again. FIG.
3 shows another conventional example of a vertical mill for coarse crushing. 1
Is a table driven to rotate by a motor (not shown),
Reference numeral 2 denotes a coal feeding pipe hanging above the central portion of the table 1, and the coal feeding pipe 2 is also rotationally driven.

3 is raw coal, 4 is a roller which rotates in contact with the table 1, 5 is crushed coal, 6 is conveying air, 7 is a mill casing, 9 is an inner wall surface of the casing 7 around the table 1. The fixed drift plate 10 is an outlet pipe on the casing 7 side surrounding the coal feeding pipe 2. In the vertical mill for coarse crushing shown in FIG. 13, the table 1 and the coal feeding pipe 2 are rotationally driven, and the raw coal 3 is fed from the coal feeding pipe 2 to the central portion of the table 1, and on the table 1. The particles are blown to the outer peripheral side of the table 1 by the centrifugal force, are caught between the rollers 4 and are crushed into crushed carbon 5.

The crushed coal 5 is blown up upward in the mill casing 7 by the conveying air 6 blown up from the lower side of the mill and ascends, and from the outlet pipe 10 to a transport pipe (not shown).
To a combustion furnace (PFBC (pressurized fluidized bed) boiler) (not shown) through which the combustion gas is combusted, and the combustion gas is further passed through a dust filter (not shown) and the like to a gas turbine (not shown). ) To be reused.

At this time, the conveying air 6 blown up from the lower side of the mill by the deflector 9 located around the table 1.
Is deflected, the crushed coal 5 is inertially classified, and the coarse particles are returned to the central portion of the table 1 to be crushed again. Rotation of the coal feeding pipe 2 is carried out in order to scrape off pulverized coal components deposited and accumulated on the wall of the coal feeding pipe 2 with a fixed scraping rod (for example, a scraper: see 2'in FIG. 14). Is.

[0008]

The conventional vertical mill for coarse grinding shown in FIGS. 12 and 13 has the following problems.
That is, (1) the average particle size of the crushed coal 5 required in a combustion furnace (PFBC (pressurized fluidized bed) boiler) is about 1 to 2 mm, and there is a problem such as adhesion to a short-pass (blowing) pipe in a boiler. It is desirable that the particle size of the fine powder contained in the crushed coal 5 is 0.3 mm or less as much as possible. However, in the raw coal supplied from the coal feeding pipe 2 to the table 1, 5 or less fine particles of 0.3 mm or less are contained. The content of the fine powder in the raw coal 3 supplied from the coal feeding pipe 2 to the table 1 is increased by the roller 4 because the content of the fine powder is 15% and further pulverized by the roller 4 to increase the content rate of the fine powder of 0.3 mm or less. It is necessary to prevent crushing and suppress an increase in fine powder content. (2) If the content of the fine powder in the pulverized coal 5 supplied to the combustion furnace (PFBC (pressurized fluidized bed) boiler) is too high, blow-through occurs in the combustion furnace and complete combustion does not occur in the combustion furnace. It becomes unburned and finally adheres to the dust filter.
There was a problem that the dust filter was burnt and burned out.

The present invention is proposed in view of the above problems, and an object thereof is to supply the optimum pulverized coal having a small pulverized coal content to a combustion furnace and to use the amount of raw coal pulverized by rollers. The point is to provide a vertical mill for coarse crushing, which can reduce (amount of raw coal falling on the table) and reduce crushing power.

[0010]

In order to achieve the above object, a vertical mill for coarse crushing of the present invention has a raw material dispersion plate disposed below a coal feeding pipe. In the vertical mill for coarse crushing, the raw material dispersion plate may be a dispersion plate having a conical upper surface, and the dispersion plate may be attached to the lower part of the coal feeding pipe via a connecting rod (claim 2).

In the vertical mill for coarse crushing, the raw material dispersion plate may be attached to the center of the upper surface of the table via a support tube so that the plate can be rotated together with the table (claim 3). Further, in the vertical mill for coarse pulverization of the present invention, the conical dispersion plate is arranged below the coal feeding pipe, and the casing is provided with the multistage tapered portion.

[0012]

The vertical mill for coarse crushing of the present invention is constructed as described above and has the following functions. That is, (1) In the vertical mill for coarse crushing according to claim 1, when the raw coal falling from the coal feeding pipe collides with the conical raw material dispersion plate and is dispersed and drops toward the table, the raw coal is Since the fine powder inside is blown up by the transport air and pneumatically sent upward, the content of the fine powder in the pulverized coal discharged from the outlet pipe is the content of the fine powder in the raw coal supplied from the coal feeding pipe. The optimum pulverized coal having a small pulverized coal content rate is suppressed to about + 3% and is supplied to a combustion furnace (PFBC (pressurized fluidized bed) boiler).
Further, the amount of raw coal crushed by the rollers (the amount of raw coal falling on the table) is reduced, and the pulverization power is reduced. (2) In the vertical mill for coarse crushing according to claim 2, when the raw coal falling from the coal feeding pipe collides with the conical portion formed on the upper surface of the raw material dispersion plate, is dispersed, and drops toward the table. ,
The fine powder in the raw coal is blown up by the transport air and pneumatically sent upwards, so even with this vertical mill for coarse pulverization, the optimum pulverized coal with a small pulverized coal content is supplied to the combustion furnace,
The grinding power is reduced. (3) In the vertical mill for coarse crushing according to claim 3, the raw coal dropped from the coal feeding pipe once collides with the raw material dispersion plate and the conical portion which are rotating together with the coal feeding pipe, and centrifugalizes these parts. It is blown radially outward by force, and the fine powder in the raw coal is blown up by the carrier air and pneumatically sent upwards. Is supplied to the combustion furnace, and the grinding power is reduced. (4) In the vertical mill for coarse crushing according to claim 4, when the raw coal falling from the coal feeding pipe collides with the conical dispersion plate and drops along the dispersion plate, fine powder in the raw coal is generated. Since it is blown up by the conveying air and pneumatically sent upward, even in this vertical mill for coarse crushing, the optimum crushed coal with a small pulverized coal content is supplied to the combustion furnace and the crushing power is reduced. . In addition, among the crushed coal coarsely crushed on the table, large coarse powder and medium coarse powder collide with the steep taper part at the bottom of the mill casing around the table, and the large coarse powder falls again on the table and is conveyed. Medium coarse powder, which easily separates from the working air, collides with the flat part under the dispersion plate, drops onto the table, and is re-ground.
Coarse powder (product) is pneumatically sent upward, while the gentle taper in the middle of the mill casing gradually increases the airflow velocity, causing the coarse powder (product) to stall and drop onto the table. Then, it is not over-pulverized and the generation of fine powder is reduced. From this point as well, the optimum pulverized coal having a small content of fine powder is supplied to the combustion furnace.

[0013]

【Example】

(First Embodiment) Next, a vertical mill for coarse crushing of the present invention will be described with reference to a first embodiment shown in FIG. 1. 1 is a table driven by a motor (not shown) to rotate-and 2 is the same table. 1
Of the coal feeding pipe hanging above the center of the table, 3 is raw coal, 4 is a roller which rotates in contact with the table 1, 5 is crushed coal, 6 is conveying air, 7 is a mill casing, 8 is the above coal feeding A support plate attached to the lower portion of the pipe 2, 11 is a fixed type classification blade whose one end is supported by the support plate 8, 9 is a deflector plate fixed to the inner wall surface of the mill casing 7 around the table 1, and 10 is the above. It is an outlet pipe on the mill casing 7 side that surrounds the coal feeding pipe 2.

Reference numeral 13 is a conical raw material dispersion plate, which is the most characteristic feature of the present embodiment. The raw material dispersion plate 13 is composed of a plurality of (four in this embodiment) connecting rods 12 from the lower end of the coal feeding pipe 2. And a vertical distance δ of about 50 to 150 mm between the lower end of the coal feeding pipe 2 and the apex of the raw material dispersion plate 13. Next, the operation of the vertical mill for coarse grinding shown in FIG. 1 will be specifically described.

The raw coal 3 falling from the coal feeding pipe 2 collides with the conical raw material dispersion plate 13, is dispersed, and drops toward the table 1. During this process, fine powder in the raw coal 3 is conveyed. It is blown up by the air 6 and is pneumatically sent upwards to the table 1.
The raw coal 3 falling upward contains only a small amount of fine powder of 0.3 mm or less. For example, if the content rate of the fine powder contained in the raw coal 3 falling from the coal feeding pipe 2 is 10%, the raw coal 3 falling onto the table 1 contains about 1% of fine powder. It's just that.

On the other hand, the fine powder that is blown up by the above-mentioned carrying air 6 and is sent upward is not crushed, but is discharged into the outlet pipe 1.
Since it is discharged from 0 to the transportation pipe, the content of fine powder of the crushed carbon 5 in the transportation pipe can be minimized. In the vertical mill for coarse pulverization of the first embodiment, (1) when the raw coal falling from the coal feeding pipe 2 collides with the conical raw material dispersion plate 13 and is dispersed and drops toward the table 1, Since the fine powder in the raw coal 3 is blown up by the conveying air 6 and is pneumatically sent upward, the content ratio of the fine powder in the pulverized coal discharged from the outlet pipe 10 is supplied from the coal feeding pipe 2. The content of fine powder in 3 is suppressed to about + 3%, and optimum pulverized coal having a small content of pulverized coal is supplied to the combustion furnace (PFBC (pressurized fluidized bed) boiler). (2) The amount of raw coal crushed by the roller 4 (the amount of raw coal dropped on the table) is reduced, and the pulverization power is reduced.

(Second Embodiment) Next, a vertical mill for coarse grinding according to the present invention will be described with reference to a second embodiment shown in FIGS. 2 and 3.
1 to 7, 9 and 10 are the same parts as described above, 13a is a raw material dispersion plate which is the most characteristic of this embodiment, and 13b is a conical portion formed on the upper surface of the raw material dispersion plate 13a.
A plurality of 3a are provided from the lower end portion of the coal feeding pipe 2 (in this embodiment, 4
It is suspended and supported by a connecting rod 12.

Next, the operation of the vertical mill for coarse crushing shown in FIGS. 2 and 3 will be specifically described. The raw coal 3 falling from the coal feeding pipe 2 is a conical portion 1 formed on the upper surface of the raw material dispersion plate 13a.
3b is collided and dispersed, and falls toward the table 1. On the way, the fine powder in the raw coal 3 is blown up by the transport air 6 and is pneumatically sent upward to fall on the table 1. 3 contains only a small amount of fine powder of 0.3 mm or less.

For example, if the content of the fine powder contained in the raw coal 3 falling from the coal feeding pipe 2 is 10%, about 1% of the fine powder is contained in the raw coal 3 falling on the table 1. Is only included. On the other hand, the fine powder blown up by the transport air 6 and sent upward is discharged to the transport pipe from the outlet pipe 10 without being crushed. Therefore, the fine powder content of the crushed carbon 5 in the transport pipe is minimum. It can be suppressed to the limit.

FIG. 4 shows that the same average particle size (1 mm) was 0.
The result of comparing the ratio of fine powder of 3 mm or less between the conventional example and this example is shown. In the conventional example, it was improved from about 25% to about 18% in this example. In the vertical mill for coarse crushing of the second embodiment, the coal feeding pipe 2
When the raw coal 3 falling from the collision collides with the conical portion 13b formed on the upper surface of the raw material dispersion plate 13a and is dispersed and drops toward the table 1, the fine powder in the raw coal 3 is blown up by the transport air 6. Then, even in this vertical mill for coarse crushing, the optimum crushed coal having a small pulverized coal content is supplied to the combustion furnace and the crushing power is reduced.

(Third Embodiment) Next, a vertical mill for coarse crushing of the present invention will be described with reference to a third embodiment shown in FIGS. 5 and 6.
1 to 7, 9 and 10 are the same parts as described above, 13a is a raw material dispersion plate which is the most characteristic of this embodiment, and 13b is a conical portion formed on the upper surface of the raw material dispersion plate 13a.
3a is attached to the center of the upper surface of the table 1 via a support tube 14, and the support tube 14, the raw material dispersion plate 13a, and the conical portion 13b rotate together with the table 1. The upper surface height of the raw material dispersion plate 13a is hmm higher than that of the roller 4.
(H = 10 to 50 mm).

Next, the operation of the vertical mill for coarse grinding shown in FIGS. 5 and 6 will be specifically described. The support tube 14, the raw material dispersion plate 13a, and the conical portion 13b rotate together with the table 1. At this time, the raw coal 3 falling from the coal feeding pipe 2 collides with the conical portion 13b formed on the upper surface of the raw material dispersion plate 13a, and is blown outward in the radial direction by the centrifugal force. Is dispersed by the carrier air 6, so that the fine powder rides on the flow of the carrier air, heads toward the outlet pipe 10, drops onto the table 1, and is not crushed.
The proportion of fine powder in the pulverized coal supplied to the combustion furnace is reduced.

For example, if the content rate of the fine powder contained in the raw coal 3 falling from the coal feeding pipe 2 is 10%, about 1% of the fine powder is contained in the raw coal 3 falling on the table 1. Is only included. On the other hand, the fine powder blown up by the transport air 6 and sent upward is discharged to the transport pipe from the outlet pipe 10 without being crushed. Therefore, the fine powder content of the crushed carbon 5 in the transport pipe is minimum. It can be suppressed to the limit.

FIG. 7 shows that the same average particle size (1 mm) was 0.
The result of comparing the ratio of fine powder of 3 mm or less between the conventional example and this example is shown. In the conventional example, it was improved from about 25% to about 18% in this example. In the vertical mill for coarse crushing of the third embodiment, the coal feeding pipe 2
The raw coal 3 dropped from the colliding once collides with the raw material dispersion plate 13a and the conical portion 13b which are rotating together with the coal feeding pipe 2, and is blown outward in the radial direction by the centrifugal force of these parts. Since the fine powder is blown up by the carrier air 6 and pneumatically sent upward, even in this vertical mill for coarse pulverization, optimum pulverized coal having a small pulverized coal content is supplied to the combustion furnace.
The grinding power is reduced.

(Fourth Embodiment) Next, a vertical mill for coarse crushing of the present invention will be described with reference to a fourth embodiment shown in FIGS. 8 to 11. 1 to 4, 7 and 10 are the same parts as described above. Reference numeral 13 denotes a conical dispersion plate, which is disposed below the coal feeding pipe 3 and is attached to the mill casing by a stee 13a as shown in FIG.

The reference numeral 7a designates a steep taper portion formed in the lower portion of the mill casing 7, and 7b designates a gentle taper portion formed in the middle portion of the mill casing 7.
a and 7b. Next, the operation of the vertical mill for coarse grinding shown in FIGS. 8 to 11 will be specifically described. The raw coal 3 falling from the coal feeding pipe 2 collides with the conical dispersion plate 13 and drops along the distribution plate 13, but at that time, it is blown up by the transport air (hot air) 6 and the primary drying is performed. As shown in FIG. 10, fine powder 5d having a size of 0.3 mm or less and coarse powder having a size of about 1 mm (product) are included in the raw coal 3 as shown in FIG.
5c is pneumatically sent upward and discharged from the outlet pipe 10 to the outside of the mill.

On the other hand, the large coarse powder 5a of 5.7 mm or more and the medium coarse powder 5b of several mm to 5.7 mm have a larger gravity than the buoyancy caused by the air flow, so they drop onto the table 1 and the load device. It is coarsely crushed by the pressing force applied from 14 to the table 1 via the roller 4. The crushed coal is blown to the outer peripheral portion of the table 1 by the centrifugal force of the rotating table 1, contacts the conveying air (hot air) 6, and is subjected to secondary drying.

The lower portion of the mill casing 7 around the table 1 forms a steep taper portion 7a, which protrudes above the outer peripheral portion of the table 1 and is larger than the crushed coal roughly crushed as described above. The coarse powder 5a and the medium coarse powder 5b have a sharp taper portion 7
When it collides with a, the large coarse powder 5a falls onto the table 1 again, and the medium coarse powder 5b easily separates from the conveying air (hot air) 6, collides with the lower part of the dispersion plate 13, and also onto the table 1. It falls, is pulverized again, becomes coarse powder 5c (product), and is sent upward by air.

At this time, the middle portion of the mill casing 7 is
Since it is a gentle taper portion 7b and the airflow velocity gradually increases, the coarse powder (product) 5c stalls, falls onto the table 1 and is not overcrushed, and fine powder 5d is also generated. Less. FIG. 11 shows the dimensions and angles of the dispersion plate 13 and the mill casing 7. Test result, d / D
= 0.25 to 0.75, θ ₁ = 40 ° to 70 °, θ ₂ =
40 ° to 70 ° and θ ₃ = 5 ° to 30 ° were appropriate.

The reason is that when d / D> 0.25, the dispersion effect is reduced due to the insufficient wind speed at the outer peripheral portion of the dispersion plate 13 and the insufficient distance between the conical portions of the dispersion plate 13, and when d / D> 0.75 the dispersion effect is reduced. The effect is good, but the pressure loss increases significantly, and when θ ₁ <40 °, the raw coal does not fall smoothly, and when θ ₁ <70 °, the downward vector of the raw coal increases and the dispersion effect decreases. ,
When θ ₂ <40 °, it is difficult for the large coarse powder of the collision mark to return to the table, when θ ₂ <70 °, the pressure loss increases, and when θ ₃ <5 °, the airflow velocity does not increase so much. ) Is apt to stall, and the pressure loss increases when θ ₃ <30 °.

When the vertical mill for coarse crushing of this example was applied to three types of coal having different properties, as shown in Table 1, good results sufficiently satisfying the target values were obtained for all types of coal. It was This is due to the dispersion separation effect of the fine powder 5d in the coal and the coarse powder (product) 5c in the coal by the dispersion plate 13, the large coarse powder collision classification effect of the steep taper portion 7a, and the medium coarseness of the lower flat portion of the dispersion plate 13. This is due to the collision classification effect of the powder 5b and the fall prevention effect of the coarse powder (product) 5c of the gently tapered portion 7b.

In the vertical mill for coarse grinding of the fourth embodiment,
(1) When the raw coal 3 falling from the coal feeding pipe 2 collides with the conical dispersion plate 13 and drops along the dispersion plate 13,
The fine powder in the raw coal 3 is blown up by the transfer air 6,
Since it is pneumatically fed upward, even in this vertical mill for coarse pulverization, optimum pulverized coal having a small pulverized coal content is supplied to the combustion furnace, and the pulverization power is reduced. (2) Of the crushed coal coarsely crushed on the table 1, the large coarse powder 5a and the medium coarse powder 5b collide with the sharp taper portion 7a formed in the lower portion of the mill casing 7 around the table 1 to obtain the large coarse powder. The powder 5a drops onto the table 1 again, and the medium coarse powder 5b, which easily separates from the conveying air 6, collides with the flat portion below the dispersion plate 13, and again the table 1
The air flow velocity gradually increases due to the gentle taper portion 7b formed in the middle portion of the mill casing 7 while falling upward, re-pulverized into coarse powder (product) and pneumatically fed upward. , The coarse powder (product) stalls, falls onto the table,
It will not be over-milled and the generation of fine powder will be reduced,
From this point as well, the optimum pulverized coal having a small content of fine powder is supplied to the combustion furnace.

[0033]

The vertical mill for coarse crushing of the present invention is constructed as described above, and the following effects can be achieved. That is, (1) In the vertical mill for coarse crushing according to claim 1, when the raw coal falling from the coal feeding pipe is made to collide with the conical raw material dispersion plate to be dispersed and dropped toward the table, the raw coal is Since the fine powder inside is blown up by air for transportation and pneumatically sent upwards, the content rate of the fine powder in the crushed coal discharged from the outlet pipe is + 3% in the raw coal supplied from the coal feeding pipe. The optimum pulverized coal having a small pulverized coal content can be supplied to a combustion furnace (PFBC (pressurized fluidized bed) boiler). Further, the amount of raw coal crushed by the rollers (the amount of raw coal dropped on the table) can be reduced, and the crushing power can be reduced. (2) In the vertical mill for coarse crushing according to claim 2, when the raw coal falling from the coal feeding pipe is collided with the conical portion formed on the upper surface of the raw material dispersion plate to be dispersed and dropped toward the table. Since the fine powder in the raw coal is blown up by the conveying air and pneumatically sent upward, even with this vertical mill for coarse pulverization, the optimum pulverized coal with a small pulverized coal content can be supplied to the combustion furnace.
The grinding power can be reduced. (3) In the vertical mill for coarse crushing according to claim 3, the raw coal dropped from the coal feeding pipe is caused to once collide with the raw material dispersion plate and the conical portion which are rotating together with the coal feeding pipe, and the centrifugal force is applied to these portions. It is blown outwards in the radial direction by force, and the fine powder in raw coal is blown up by the carrier air and pneumatically sent upward.Therefore, even in this vertical mill for coarse pulverization, the optimum pulverized coal with a low pulverized coal content is burned in the combustion furnace. And the grinding power can be reduced. (4) In the vertical mill for coarse crushing according to claim 4, when the raw coal falling from the coal feeding pipe is collided with a conical dispersion plate and dropped along the dispersion plate, fine powder in the raw coal is generated. Since it is blown up by the conveying air and pneumatically sent upward, even with this vertical mill for coarse crushing, the optimum crushed coal with a small pulverized coal content can be supplied to the combustion furnace and the crushing power can be reduced. Also, of the crushed coal coarsely crushed on the table, large coarse powder and medium coarse powder collide with the sharp taper part of the lower part of the mill casing around the table, and the large coarse powder is dropped onto the table again for transportation. The medium coarse powder, which is easily dislodged from the air, collides with the flat part under the dispersion plate, drops it on the table again, and re-pulverizes it into coarse powder (product), which is pneumatically fed upward, while the middle part of the mill casing Since the airflow velocity is gradually increased by the gentle taper part, coarse powder (product) is stalled and dropped onto the table without over-pulverization, and the generation of fine powder can be reduced. It is possible to supply the optimum crushed coal with a small content of fine powder to the combustion furnace.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a first embodiment of a vertical mill for coarse crushing of the present invention.

FIG. 2 is a vertical cross-sectional side view showing a second embodiment of the vertical mill for coarse crushing.

3 is an enlarged perspective view showing an arrow A portion of FIG.

FIG. 4 is an explanatory view showing a ratio of fine powder in the second example and the conventional example.

FIG. 5 is a vertical sectional side view showing a third embodiment of the vertical mill for coarse crushing.

6 is a cross-sectional plan view taken along the line BB of FIG.

FIG. 7 is an explanatory view showing a ratio of fine powder in the third embodiment and the conventional example.

FIG. 8 is a vertical sectional side view showing a fourth embodiment of the vertical mill for coarse crushing.

FIG. 9 is a plan view showing a mounting portion of a conical dispersion plate of the vertical mill for coarse crushing.

FIG. 10 is an explanatory view of the operation of the vertical mill for coarse crushing.

FIG. 11 is an explanatory diagram showing dimensions and angles of a conical dispersion plate and a mill casing of the vertical mill for coarse grinding.

FIG. 12 is a vertical cross-sectional side view showing an example of a conventional vertical mill for coarse grinding.

FIG. 13 is a vertical cross-sectional side view showing another example of a conventional vertical mill for coarse grinding.

FIG. 14 is a vertical sectional side view showing a scraper for a coal feeding pipe in the vertical mill for coarse crushing.

[Explanation of symbols]

 1 Table 2 Coal feeding pipe 3 Raw coal 4 Roller 5 Crushed coal 6 Air for transportation 7 Mill casing 8 Support plate 9 Drift plate 10 Outlet pipe 11 Fixed type classification blade

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroki Yamaguchi 1-1 1-1 Atsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard Co., Ltd.

Claims (4)

[Claims] 1. A vertical mill for coarse crushing, wherein a raw material dispersion plate is disposed below a coal feeding pipe. 2. The vertical mill for coarse crushing according to claim 1, wherein the raw material dispersion plate is a conical dispersion plate having an upper surface and is attached to a lower portion of the coal feeding pipe via a connecting rod. 3. The vertical mill for coarse crushing according to claim 1, wherein said raw material dispersion plate is attached to the center of the upper surface of the table via a support tube, and this can be rotated together with the table. 4. A vertical mill for coarse crushing, characterized in that a conical dispersion plate is arranged below the coal feeding pipe and a multistage taper portion is formed on the mill casing.