JP2000312832A - Vertical mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the height of the whole vertical mil to miniaturize the vertical mill, to form a rotary shaft of a rotary classifier with a solid small- diameter shaft to eliminate the necessity of a special large-diameter bearing, and to reduce the costs as a whole. SOLUTION: A coal supply pipe 30 is disposed at the side of a casing 2, and a conveyance device 34 is mounted at the side of the casing 2 to supply a granular material such as coal fed from the coal supply pipe 30 onto a table 5 in the easing 2. Rotary vanes 28 are arranged on a rotary shaft 20 so that the rotary vanes 28 project radially from the rotary shaft 20 to the direction of its radius, thereby forming a rotary classifier 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a mill for pulverizing a granular material such as coal supplied to a coal-fired boiler to obtain a fine powder such as pulverized coal, there is a conventional mill as shown in FIG.
In FIG. 4, reference numeral 1 denotes a vertical mill.

[0003] In the lower part of the casing 2 of the vertical mill 1, a table 5 which is rotationally driven by a driving device 3 such as a motor via a speed reducer 4 is arranged. The pivot bracket 6 is attached to the casing 2
The pivot bracket 6 is provided with a roller 8 that rotates about an axis O extending in a direction substantially perpendicular to the horizontal shaft 7 at the tip of the pivot bracket 6. A fluid pressure cylinder 9 using a fluid such as oil is attached to the journal cover 2 a of the casing 2, and a rod 9 a of the fluid pressure cylinder 9 is extended to fit into the plunger housing 10. By pressing the pressing portion 6a of the pivot bracket 6 via the plunger 11, the roller 8 is pressed against the upper surface of the horizontally rotating table 5, and the roller 8 and the table 5 cooperate, and the coal or the like on the table 5 Can be crushed.

In the casing 2, an annular body 12 is disposed so as to surround the table 5, and the annular body 12 has
An air port 14 is provided so that the primary air 13 introduced into the casing 2 from a position below the table 5 of the casing 2 can be blown into the upper portion of the casing 2.

A head frame 15 is provided outside the upper portion of the casing 2 so as to communicate with the inside of the casing 2, and a bearing tube 16 is fixed in the head frame 15 so as to extend vertically. Bearings 17 and 18 are fitted in the bearing cylinder 16 at a predetermined interval A in the vertical direction, and fine powder such as pulverized coal is burned into a side portion of the head frame 15 by a burner (not shown) of a boiler. A fine powder feed pipe 19 for feeding the powder is connected.

A hollow cylindrical rotary shaft 20 extending vertically is fitted into the bearings 17 and 18, and a rotary classifier 21 is mounted on a portion of the rotary shaft 20 extending into the casing 2.
A pulley 22 is fitted to a portion of the rotary shaft 20 extending above the bearing tube 16.
A pulley 25 is fitted to an output shaft 24 of a driving device 23 such as a motor with a speed reducer installed outside the upper portion of the casing 2. The pulley 25 and the pulley 22 fitted to the rotary shaft 20 are connected to each other. An endless belt 26 is looped between them.

In the rotary classifier 21, a rotary plate 27 is fitted to the lower end of the rotary shaft 20, and an outer peripheral portion of the rotary plate 27 is
The rotary classifier 21 has a configuration in which a large number of flat blades 28 extending upward are provided, and the weight of the rotary classifier 21 is supported by a bearing 17 disposed above the bearing cylinder 16. On the other hand, when the rotary classifier 21 rotates, the radial load acting on the rotating classifier 21 is reduced by the bearing 18 located below the bearing cylinder 16.
Therefore, a bearing such as a conical roller bearing is used as the bearing 17, and a bearing such as a cylindrical roller bearing is used as the bearing 18. In FIG. 4, reference numeral 29 denotes a support beam that protrudes radially from the rotation shaft 20 to support the rotor 28.

Also, inside the rotary shaft 20, a coal feed pipe 30 having an upper end connected to a chute of a coal feeder (not shown).
Are arranged to open slightly above the roller 8 in the casing 2.

Further, a truncated inverted conical reject chute 31 is provided in the casing 2 so as to be located below the rotary classifier 21. A slit 32 extending along the inclined surface is formed so that a powder obtained by pulverizing a granular material such as coal blown up by the air 13 can pass therethrough.

In the vertical mill 1 shown in FIG. 4, granular material such as coal cut out from a coal hopper (not shown) to a coal feeder is supplied from a chute of the coal feeder via a coal feed pipe 30 to a casing. 2, the table 5 which is dropped on the table 5 and is driven by the driving device 3 via the speed reducer 4 to rotate in the horizontal direction, and the roller 8 which is in contact with the table 5 and rotates. The powder such as coal, which has been pulverized by the cooperative operation of the above, rises in the casing 2 as shown by the arrow, accompanied by the primary air 13 blown out from the air port 14, and the slit 32 of the reject chute 31
Through the reject chute 31, the coarse powder is classified by the rotary classifier 21 driven by the driving device 23 and rotating together with the rotary shaft 20,
Fine powder such as pulverized coal obtained by classifying coarse powder is supplied to a rotary classifier 21.
Into the head frame 15, is sent out from the head frame 15 to the fine powder feed pipe 19, is sent to a burner (not shown) of the boiler, and is coarsely classified by the rotary classifier 21. Is slid down the reject chute 31 and returned to the table 5.

[0011]

In the case of the conventional vertical mill 1 as described above, the rotary shaft 2 of the rotary classifier 21 is used.
Since the rotary wings 28 are arranged in the vertical direction so as to extend substantially parallel to 0, the height at the rotary wing 28 portion of the rotary classifier 21 increases, and accordingly, the rotary classifier 2
The position G of the center of gravity of the rotating blade 28 of the
Since the distance B from the bearing 18 such as a cylindrical roller bearing for supporting the radial load of the rotary classifier 21 which is located below the rotary classifier 21 becomes longer, the rotary classifier 21 is stably supported. To do this, the lower bearing 18
The distance A between the bearing 17 and a conical roller bearing or the like for supporting the weight of the rotary classifier 21 and the load in the radial direction located above the bearing cylinder 16 must also be increased. However, the height of the entire vertical mill 1 is increased, which leads to an increase in cost. In addition, the building of the vertical mill 1 has to be enlarged, which is disadvantageous in terms of layout and the like.

A coal feed pipe 30 is disposed at the center of the vertical mill 1, and a rotary classifier 21 is provided around the feed pipe 30.
Is disposed, the rotating shaft 2 of the rotary classifier 21 is
Numeral 0 denotes a hollow large-diameter shaft, which requires special large-diameter bearings as the bearings 17 and 18. This also leads to an increase in cost and has a problem that maintenance of the bearings 17 and 18 is not easy. .

In view of such circumstances, the present invention can reduce the height of the vertical mill as a whole to achieve downsizing, reduce the size of the vertical mill building, and rotate the rotary shaft of the rotary classifier. To provide a vertical mill that can eliminate the need for a special large-diameter bearing as a solid small-diameter shaft, facilitate its maintenance, and reduce the cost and increase the degree of freedom in layout and other aspects as a whole. Things.

[0014]

According to the present invention, there is provided a table which is disposed in a lower part of a casing so as to be rotatable in a horizontal direction, a coal feed pipe for supplying a granular material onto the table, and a granular material which is pressed against the upper surface of the table. , A powder crushed by the roller and blown up by a rotating wing that is driven to rotate about a rotating shaft extending in the vertical direction, and a coarse powder falling on a table and passing through the rotating wing. In a vertical mill equipped with a rotary classifier that classifies fine particles into fine powder, a coal feed pipe is arranged on the side of the casing, and the granular material supplied from the coal feed pipe is fed onto a table in the casing. A vertical classifier is formed by disposing a rotating blade on the rotating shaft so as to radially project from the rotating shaft in the radial direction while attaching the transfer device to the casing side. Those relating to the mill.

In the vertical mill, the transfer device may be a screw feeder.

According to the above means, the following effects can be obtained.

The granular material is fed into the conveying device from the coal feed pipe, is fed onto the table in the casing by the operation of the conveying device, and comes into contact with the horizontally rotating table and the table to rotate. The powder is pulverized and blown up in cooperation with a roller, and the pulverized and blown-up powder is classified into coarse powder by a rotating blade of a rotary classifier rotating together with a rotating shaft, and the coarse powder is classified. Fine powder
The coarse powder that has been sent to a boiler or the like after passing through a rotary classifier, and that has been classified by the rotating blades of the rotary classifier, is returned to the table.

In the case of the vertical mill according to the present invention, the height of the rotary blade portion of the rotary classifier is set so that the rotary blades are arranged so as to radially project in the radial direction with respect to the rotary shaft extending in the vertical direction. Since the coal feed pipe is not located at the center of the vertical mill, there is no need to arrange a rotary classifier around the feed pipe. The rotating shaft is a solid small-diameter shaft, eliminating the need for special large-diameter bearings.

[0019]

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

FIGS. 1 to 3 show an embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIG. 4 represent the same components, and the basic configuration is shown in FIG. The present embodiment is the same as the conventional one shown in FIG. 1, but the feature of the illustrated example is that, as shown in FIGS. A conveying device 34 for feeding the supplied granular material such as coal onto the table 5 in the casing 2 is attached to the side of the casing 2, while the conveying device 34 radially projects from the rotating shaft 20 radially from the rotating shaft 20. The point is that the rotary wings 28 are provided to form the rotary classifier 21.

In the illustrated example, a screw feeder in which a screw blade 36 is driven to rotate by a driving device 35 such as a motor equipped with a speed reducer is used as the transfer device 34.

In the rotary classifier 21, a driving device 23 such as a motor with a speed reducer is installed at a central portion on the head frame 15 via a support 37, and the output shaft 24 of the driving device 23 is An annular body 33 having an outer diameter slightly smaller than the inner diameter of the casing 2 while directly connecting the rotating shaft 20 is
As shown in FIG. 2, the rotary blade 20 is arranged so as to be concentric with the rotary shaft 20, and the rotary shaft 20 and the annular body 33 are connected by a rotary blade 28.
8 is provided with a required inclination angle α with respect to the horizontal direction based on the rotation direction of the rotating shaft 20, as shown in FIG. Needless to say, in the rotary classifier 21, the annular body 33 may be eliminated and the rotary blade 28 may be formed simply like a normal ceiling fan. Also, in FIG.
Numeral 38 denotes a fine-powder-prevention sealing device provided on the rotary shaft 20 for preventing the fine powder pulverized in the vertical mill 1 from blowing out.

Next, the operation of the illustrated example will be described.

Granules such as coal cut out from a coal hopper (not shown) to a coal feeder are fed from a chute of the coal feeder to a transfer device 34 through a coal feed pipe 30, The table 5 is fed by the operation onto the table 5 in the casing 2, is driven by the drive unit 3 via the speed reducer 4, and rotates in the horizontal direction, and the roller 8 is in contact with the table 5 and rotates. The powder such as coal pulverized by the cooperative operation of the casing 2 is entrained by the primary air 13 blown out from the air port 14 and the casing 2
The coarse powder is classified by the rotating blades 28 of the rotary classifier 21 which is driven by the driving device 23 and rotates together with the rotary shaft 20 as shown by the arrow, and the coarse powder is classified. The fine powder passes through a rotary classifier 21 and is sent from a fine powder feed pipe 19 to a burner (not shown) of a boiler.
The coarse powder classified by the rotating blades 28 of the rotary classifier 21 is returned to the table 5.

In the case of the vertical mill 1 in the illustrated example, the rotary blades 28 are disposed so as to project radially in the radial direction with respect to the rotary shaft 20 extending in the vertical direction.
The height of the rotor 28 portion does not increase, and
Since the coal feed pipe 30 is not arranged at the center of the vertical mill 1, the rotary classifier 21 does not need to be disposed around the coal feed pipe 30, and the rotation of the rotary classifier 21 is thereby reduced. Axis 20
Is a solid small diameter shaft, and special large diameter bearings are not required.

Thus, the height of the entire vertical mill 1 can be reduced to achieve downsizing, the building of the vertical mill 1 can be reduced in size, and the rotary shaft 20 of the rotary classifier 21 can be reduced to a solid small diameter. A special large-diameter bearing may not be required as the shaft, and its maintenance can be easily performed. As a result, the cost can be reduced and the degree of freedom in layout and the like can be increased as a whole.

It should be noted that the vertical mill of the present invention is not limited to the illustrated example described above, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0028]

As described above, according to the vertical mill of the present invention, the height of the entire vertical mill can be reduced to achieve downsizing, and the building of the vertical mill can be downsized. In addition, a special large-diameter bearing can be unnecessary because the rotary shaft of the rotary classifier is a solid small-diameter shaft, the maintenance thereof can be easily performed, and the overall cost can be reduced and the degree of freedom in layout and the like can be increased. This can provide an excellent effect.

[Brief description of the drawings]

FIG. 1 is an overall schematic side sectional view of an example of an embodiment of the present invention.

FIG. 2 is a plan view of an example of an embodiment of the present invention, and is a view corresponding to the direction of arrows II-II in FIG.

FIG. 3 is a view taken in the direction of arrows III-III in FIG. 2;

FIG. 4 is an overall schematic side sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical mill 2 Casing 5 Table 8 Roller 18 Bearing 20 Rotating shaft 21 Rotary classifier 28 Rotating blade 30 Coal supply pipe 34 Conveyor

Claims (2)

[Claims] 1. A table disposed at a lower part in a casing so as to be rotatable horizontally, a coal feed pipe for supplying granular material onto the table, a roller pressed against the upper surface of the table to crush the granular material, and the roller A rotary classifier that classifies the powder crushed and blown up by the rotary wing that is driven to rotate around a rotating shaft extending in the vertical direction into coarse powder that falls on a table by being repelled by a rotary wing and fine powder that passes through the rotary wing. In a vertical mill equipped with a machine, a coal feeding pipe is arranged on a side of a casing, and a conveying device for feeding a granular material supplied from the coal feeding pipe onto a table in the casing is provided on a side of the casing. A vertical mill, wherein a rotary classifier is formed by disposing a rotary blade on a rotary shaft so as to radially project from the rotary shaft in a radial direction. 2. The vertical mill according to claim 1, wherein the conveying device is a screw feeder.