JPH06226127A - Crushing device - Google Patents

Abstract

PURPOSE:To provide a damage-free ring segment structure and thereby achieve the stable operation of a mill for a long time to increase the reliability of the mill. CONSTITUTION:The crushing device is composed of a crushing ring segment which is mounted on a rotary table rotating around a vertical shaft on a horizontal plane and is split in the circumferential rotating direction of the rotary table, and crushing rollers which rotate in such a manner that their peripheral surfaces are pressed against the outer circumferential side upper surface of the crushing ring segment or crushing balls which rotate in such a state that their outer surfaces are pressed, to crush raw material. Each segment 14, 15 of the crushing ring is split in so many pieces of part in the radial direction of the rotary table 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical roller mill (crushing device), which is not damaged by vibration of a roller or generation of abnormal impact pressure, and is a segment of a highly reliable crushing ring. It is about structure.

[0002]

2. Description of the Related Art Even in a coal-fired boiler, low-pollution combustion (low NOx, reduction of unburned matter) and wide-area load operation (change in coal supply amount) are carried out, and accordingly, high-performance pulverized coal machine (mill)
Came to be requested.

As one type of crusher for finely crushing solid fuels typified by coal, cement raw materials such as limestone or new raw materials, a vertical roller mill having a crushing table and a plurality of crushing rollers is used. It has been used and recently it is solidifying its position as one of the representative models.

This type of mill has a disk-shaped grinding table which rotates at a low speed on a horizontal plane which is driven by a motor having a speed reducer at the bottom of a cylindrical housing (container).
A plurality of crushing rollers are provided on the upper surface thereof, which are rotated by being hydraulically or pressurized by springs or the like at positions where the outer peripheral portion is equally divided in the circumferential direction.

The raw material to be pulverized supplied to the central portion of the pulverizing table moves to the outer peripheral portion in a spiral shape on the table due to the rotation of the pulverizing table and the centrifugal force generated thereby, and the pulverizing of the table. It is crushed by being caught between the race surface and the crushing roller.

The hot air sent through the duct is guided to the lower part of the mill housing, and the hot air is blown up from the air throat between the outer peripheral portion of the crushing table and the inner peripheral portion of the mill housing. There is.

The crushed powder particles are dried while rising in the mill housing by the hot air blown from the air throat. The granular material transported to the upper part of the housing falls from the coarse one due to gravity (primary classification), and the slightly fine granular material penetrating therethrough is classified again by the cyclone separator or rotary classifier installed at the upper part of the housing. The fine powder having a predetermined particle size or less is conveyed by hot air and sent to the pulverized coal burner or the fine powder storage bin in the boiler.

Coarse particles having a predetermined particle size or more, which do not penetrate the classifier, are dropped on the crushing table and are crushed again together with the raw material just supplied into the mill. In this way, the crushing roller repeats crushing.

[0009]

For example, when a tire type roller mill is to be operated under a low load, it is vibration of the mill that is a problem in reducing the load. This vibration phenomenon is complicated and its detailed mechanism has not been clarified. However, it is a kind of frictional vibration caused by the slip between the coal bed and the roller (a discontinuity, a non-linear vibration known as a stick-slip motion). Is considered to be. As the type of vibration, it can be said to be a kind of self-excited vibration because the excitation source cannot be identified as sticky and the vibration waveform has a spike shape.

In general, as shown in FIG. 10, this vibration becomes severe during low load operation (a condition in which there is little coal holdup in the mill). However, FIG.
The vibration characteristics such as are also greatly different depending on the type of coal, and some types of coal may cause severe self-excited vibration during operation under a fairly high load (condition with a lot of coal hold-up in the mill). .

11 and 12 show two examples of the supporting structure for the crushing roller. The example shown in FIG.
This is a type of roller mill in which the roller bracket 1002 that supports the end portion of the first shaft 1003 from behind is used as a pressure roller from above by using the roller pivot 1008 as a rotation spindle and a load transmission point.

Reference numeral 1004 denotes a roller rotating shaft, 1005
Is a central axis of the cross section, 1006 is a vertical axis, 1007 is a pivot box, 1009 is a pressure frame, 1010 is a pressure spring, 1011 is a spring frame, 1012.
Is a rotary table, 1013 is a grinding ring, 1014 is a grinding race, 1015 is a compressed powder layer, 1016 is a grinding raw material,
Reference numeral 1017 is a table rotation shaft.

The example of FIG. 12 is a roller mill of a type in which each crushing roller 1101 in the mill is independently held like a cantilever if the roller arm 1103 is a beam.

Reference numeral 1102 denotes a roller rotating shaft, 1104.
Is an arm lever, 1105 is a pressure device, 1106 is a housing, 1107 is a journal, 1108 is a stopper,
1109 is a rotary table, 1110 is a crushing ring, 11
11 is a crushing race, 1112 is a compressed powder layer, 1113 is a crushing raw material, 1114 is a throat vane, 1115 is a table rotating shaft, 1116 is hot air, and 1117 is a ring groove.

In any type of roller mill,
Severe self-excited vibration may occur in the low load operation range.

On the other hand, in a ball type ring mill (often called an E mill), the structure of which is shown in FIG. 13 as a cross-sectional view passing through the central axis, it is severe due to slippage (internal collapse) of the powder layer in the crushing part. May cause vibration. In this type of mill, the vibration level tends to increase under the condition that the crushing section in the mill has a relatively high load (coal holdup increases).

Reference numeral 1201 is a crushing ball, 1202 is a yoke, 1203 is a lower ring, 1204 is a rotary shaft, 1205 is a rotary shaft, 1206 is hot air, 1207 is a throat nozzle, 1208 is a housing, 1209 is an upper ring, and 1210 is a spider. An arm, 1211 is a cyclone classifier, 1212 is a raw material, 1213 is a center shout (raw material supply pipe), 1214 is a vane, and 1215 is a product fine powder discharge duct.

In any of the above-mentioned types of mills, vibration is generated, which hinders stable operation of the mill. If the equipment inside the mill is damaged due to the vibration of the mill, there is a possibility that the operation of the plant will stop and a big problem will occur.

As shown in FIG. 12, a grinding ring 1110 is provided.
Is mounted in a ring groove 1117 having a rectangular cross section which is engraved in an annular shape on the outer circumference of the rotary table 1109. here,
There is a problem with processing accuracy, etc., and it is shown in Figure 6 (exaggerated).
The ring segment 501 in the ring groove 506.
Will not be mounted well and only the center bottom of the ring segment 501 will be in contact with the surface (icicle) of the ring groove 506.

502 is a rotary table yoke, 5
Reference numeral 03 is a crushing roller, 504 is a roller rotating shaft, and 505 is a raw material compressed powder layer.

In this case, as shown in FIG. 7, the beam 602 simulating the ring segment has a central support point 60.
3, the crushing load of the pressure distribution 601 is added.

In such a case, as easily inferred, the ring segment is likely to be broken with the center support point of the beam as a branch point.

On the other hand, as in the example of FIG. 8, when the ring segment 701 is mounted with its center bottom not contacting the bottom surface of the ring groove 706, the ring segment is simulated as in the model of FIG. The beam 802 is of a type that supports both ends.

Reference numeral 702 denotes a rotary table yoke, 7
Reference numeral 03 is a crushing roller, 704 is a roller rotating shaft, 705 is a raw material compressed powder layer, 801 is a pressure distribution, and 803 is a beam support point.

Even in this case, the ring segment is easily broken at the center. After all, if the ring segment or the ring groove is not processed with sufficient accuracy, or if the ring segment is not properly attached to the ring groove, the ring segment is likely to be broken from the center.

An example of the prior art [JP 58-79553 A (Ube Industries)] is introduced in FIGS. 14, 15 and 16. As shown in FIG. 15, when the liner 1301 and the crushing roller 1304 wear in a concave shape having a rounded cross section, a concentrated load 1307 is applied to both ends of FIG. In this case, the liner 1301 is easily broken, so that the liner 1301 has stepped portions 1302 and 1303 as shown in FIG.
Is provided in order to compensate for the decrease in reliability of the liner 1301 due to the concave wear (wear parts 1305, 1306).
It wasn't perfect.

An object of the present invention is to provide a ring segment structure free from the above-mentioned breakage troubles, achieve stable long-term operation of the mill, and enhance the reliability of the mill.

[0028]

In order to solve the above problems, the present invention adopts the following structure for the crushing ring segment. In the rotary table, the segment that constitutes the crushing surface is divided into two parts, the outer peripheral side and the central axis side, and the connecting portion is provided with an uneven portion on either side,
It should not come off during operation, and the fibrous substance should be press-fitted into the connecting gap between the two divided segments. With such a structure of the ring segment, even when the crushing roller vibrates, the impact transmitted from the crushing roller to the ring segment is alleviated and dissipated.

[0029]

The impact pressure applied from the crushing roller to the segment can be alleviated by forming the segment of the rotary table into the above-described two-division structure and by press fitting the fibrous substance between the segment. It will be possible. As a result, the impact pressure on the crushing table base such as the yoke sheet for mounting the segment on the upper surface is also significantly reduced. Since the two divided segments are connected to each other by the engagement of the concave and convex portions, they do not separate from the base of the rotary table during operation.

In the present invention, although the segments are divided, the attachment and detachment work of the segments is performed only by fixing the respective end portions of both the divided segments with bolts (since the connecting portions of the divided segments are engaged with each other by projections and depressions, they are used for joining. No mechanical parts are required), and as far as bolt fixing work is concerned, the work time is almost the same as the conventional segment.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the structure of a roller mill having a crushing ring segment according to the present invention as a sectional view passing through a central axis.

This roller mill is of a type in which a tire type crushing roller 4 as a crushing medium is supported by independent roller arms 6 in a cantilever manner.

1 is a crushed raw material, 2 is a raw material supply pipe (center shout), 3 is a rotary table, 5 is a roller rotary shaft, 7 is an arm lever, 8 is a pressure device, 9 is a journal, and 10 is a stopper. , 11 is a housing, 12 is a throat vane, 13 is hot air, 14 is a divided segment of the crushing ring (inner side), 15 is a divided segment of the crushing ring (outer side), 16 is a fibrous packing, 17 is a holding plate of the divided segment , 18 is a joining member, 19 is a pressing plate for divided segments, 20 is a joining member, 21 is a table rotating shaft, 22 is a rotary classifier, 23 is a dam ring, and 24 is a product fine powder discharge duct.

The feature of the present invention resides in that the crushing ring segment is constructed as a divided body on the inner side (table rotation center axis side) and the outer side (mill housing side). Therefore, first, the structure of the crushing ring segment will be described. I will do it.

FIG. 2 is a sectional view showing the structure of a crushing ring segment embodying the present invention. In this figure, the powder layer compressed and ground between the grinding roller 210 and the grinding ring is omitted. That is, it means that the crushing section is drawn with no crushing raw material. The crushing ring is divided into a crushing ring divided segment (outside) 201 and a crushing ring divided segment (inside) 202.

In the connecting portion of the divided segments, the divided segment (outer side) 201 has a wedge-shaped concave portion, and the divided segment (inner side) 202 is also engraved with a wedge-shaped convex portion. It has come to engage. The fibrous filler 203 is inserted and pressure-bonded into the gap of the connecting portion, and the connecting portion is securely fixed with no play, and at the same time,
The vibration applied to the crushing roller 210 reduces the impact applied to the ring segment.

Split segment (outer) 20 of the grinding ring
1, the outer peripheral edge is a pressing plate 204 of the segment.
It is fixed to the rotary table 208 via the joining member 205. Similarly, the divided segment (inner side) 202 of the crushing ring has its peripheral end portion formed by the pressing plate 206 of the divided segment and the joining member 207 so that the rotary table 2 can be rotated.
It is fixed at 08.

Numeral 211 is the central axis of the cross section of the roller, and 21
2 is a rotation center axis of the roller, 213 is a housing, 214
Is a seal ring and 215 is a throat vane.

FIG. 3 is a diagram showing the installation situation of the divided segments as viewed from above. The state where the connecting portion of the divided segment (outer side) 201 of the crushing ring and the divided segment (inner side) 202 of the crushing ring is formed in an arc shape at the center of the crushing ring with the fibrous filler 203 attached is shown. It is a thing.

4 and 5 show examples in which the crushing medium in the crushing section is different from the example shown in FIG.

In FIG. 4, a plurality of crushing balls 410 as a crushing medium are circulated while rotating on the crushing ring.
This is an example in which the segment segment according to the present invention is applied to a so-called ring ball mill (often called an E mill).

Split segments 401 and 40 in this example
2. Further, the structure in which the fibrous filler 403 is used for the connecting portion is the same as that shown in FIG.

In addition, 404 is a holding plate for the divided segments, 405 is a joining member, 406 is a holding plate for the divided segments, 407 is a joining member, 408 is a rotary table, and 40.
9 is the central axis of the rotary table, 411 is the housing, 41
2 is a throat nozzle.

FIG. 5 shows an example in which the segment segment according to the present invention is applied to a ring roller mill having a different tire-roller support structure from the example of FIG. In this ring roller mill, a plurality of crushing rollers 416 are provided under a pressure frame (frame body) 441 of an integral structure via a roller bracket 417 and a roller pivot 422 which is a load transmission point and a fulcrum of a pendulum operation. They are centrally held in a mutually balanced state. Also in this type of roller mill, the structure of the connecting portion using the applied divided segments 431 and 432 and the fibrous filler 433 is as shown in FIG.
It is similar to the example shown in.

Reference numeral 413 is a crushed raw material, 414 is a raw material supply pipe (center shout), 415 is a rotary table, 4
18 is a roller shaft, 419 is a roller rotating shaft, 420
Is a vertical axis, 421 is a sectional center axis, 423 is a roller pivot, 424 is a pressing spring, 425 is a spring frame, 426 is a rotary classifier, 427 is a table rotary shaft, 428 is a housing, 429 is hot air, 430 is a throat vane, 434 is a holding plate for the segment, 43
Reference numeral 5 is a joining member, 436 is a pressing plate for divided segments, 4
37 is a joining member, 438 is a seal ring, 439 is a dam ring, and 440 is a product fine powder discharge duct.

Returning to FIG. 1, the overall structure of the roller mill equipped with the segment of the crushing ring according to the present invention will be described. The crushed raw material 1 is supplied from a raw material supply pipe (center shout) 2 located on the central axis of the upper part of the mill, and drops onto a rotary table 3 rotating at the lower part of the mill. Centrifugal force acts on the raw material on the rotary table 3, is supplied onto the crushing ring segment on the outer periphery of the rotary table 3, is engraved on the upper surface of this crushing ring segment, and has a substantially arc-shaped cross section. Then, it is crushed by the crushing roller 4.

This roller mill comprises three crushing rollers 4
Is supported by an independent roller arm 6 in a cantilever manner. The crushing load is transmitted from the pressure device 8 to the crushing roller 4 via the arm lever 7 and the journal 9. The roller arm 6 is restrained by the stopper 10 against the downward movement. As a result, the crushing roller 4 and the ring segment will not be metal-touched, but due to the vertical vibration of the crushing roller 4, a shock is repeatedly applied to the ring segment.

As described above, in this roller mill, the crushing ring segment is composed of the crushing ring divided segment (inner side) 14 and the crushing ring divided segment (outer side) 15 as the structure in the sectional view.
The connecting portion of the two divided segments has a structure in which a step in the shape of a protrusion in the lateral direction, that is, a convex projection is formed on the divided segment (inside) 14 and a concave recess is formed on the divided segment (outside) 15. I'm running.

A heat-resistant fibrous filler is provided in the gap between the meshing portions so that the divided segments 14 and 15 do not come into direct contact with each other, and the impact between the divided segments is reduced. It is becoming like this. The pulverized powder is pierced between the throat vanes 12 and is transported to the upper side of the mill while being dried by the hot air 13 blown into the mill. The coarse particles fall on the rotary table 3 due to gravity (primary classification), and are crushed again in the crushing section.

The particles passing through the primary classification section are centrifugally classified by the rotary classifier 22 (secondary classification). The relatively coarse particles penetrate between the blades of the rotary classifier 22 and are discharged from the product fine powder discharge duct 21 as product fine powder. When the target is a coal-fired boiler, it is sent directly to the pulverized coal burner (the hot air 13 becomes the primary air for combustion) or is collected in the storage bin.

The function produced by applying the present invention to a mill will be further described.

First, since the ring segment mounted on the rotary table is divided into two and the cushioning material is press-fitted into the gap between the connecting portions of the divided segments, vibration of the crushing roller or crushing ball causes vibration. Even so, the impact will be greatly reduced. This eliminates the accidental damage to the ring segment and various rotary table components, which was a problem when no countermeasure was taken. In addition, the connecting part of the split segment has a stepped structure with a convex shape on one side and a concave shape on the other side, and they are engaged with each other.Therefore, there is a problem that the divided segment may come off from the rotary table during operation of the mill. Does not happen.

By embodying the present invention with the above functions, the reliability and durability of various types of ring roller mills using tire type rollers or ring ball mills using crushed balls can be improved. Like

The crushing ring segment having the structure according to the present invention is not limited to the ring roller mill using the tire type roller described as the embodiment so far, but is also called a ring ball mill (E mill) having a structure shown in FIG. Can be applied directly to).

In this ring ball mill, the balls roll between the lower ring that rotates and the upper ring that is fixed under pressure (rotation and circulating motion on the ring).
However, when the amount of raw material (hold-up) increases in the crushing part, the balls slip and cause severe frictional vibration (stick / slip motion). Vibration is more severe on ring ball mills than on ring roller mills.

During this vibration, the ball vibrates up and down, and an impact force is also applied to the segment of the lower ring. Therefore, the ring segment having the structure according to the present invention is particularly advantageous when the breakage of the lower ring is to be prevented and the life of the lower ring is to be increased.

[0057]

The effects of the present invention can be summarized as follows.

(1) Since it is a divided type segment, the problem of segment breakage naturally disappears. Further, this can reduce the cost of purchasing and exchanging a new segment.

(2) Since the applied impact is absorbed and dissipated in the ring segment, the load on the liner portion (yoke portion) of the table is reduced. The reliability and durability of the rotary table device are improved. In other words, the service life of the mill can be greatly extended.

(3) Conventionally, in order to prevent breakage of the segment, the segment mold is processed with high precision, and special high hardness cast steel (cast iron) is finished with high precision (grinding).
However, according to the present invention, these manufacturing costs can be significantly reduced.

(4) Although related to the above effect (1), the number of mill stops for inspection or replacement of damaged parts can be reduced. Therefore, the operating cost of the entire plant can be significantly reduced.

(5) Although related to the above effect (2), since the equipment damage trouble due to vibration is eliminated, it becomes possible to operate the mill with a wide range of loads and using various coal types.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a roller mill according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a grinding ring segment.

FIG. 3 is a partial plan view of a divided segment.

FIG. 4 is a cross-sectional view showing an example in which divided segments are applied to a ring ball mill.

FIG. 5 is a configuration diagram of a roller mill according to another embodiment of the present invention.

FIG. 6 is a sectional view centering around a conventional crushing ring segment.

7 is a schematic diagram showing a state of a load applied to the crushing ring segment shown in FIG.

FIG. 8 is a sectional view centering on a crushing ring segment according to another conventional example.

9 is a schematic diagram showing a state of a load applied to the crushing ring segment shown in FIG. 7. FIG.

FIG. 10 is a vibration characteristic diagram of the roller mill.

FIG. 11 is a configuration diagram showing an example of a roller supporting and pressing mechanism to which the present invention is applied.

FIG. 12 is a configuration diagram showing another example of a roller supporting and pressing mechanism to which the present invention is applied.

FIG. 13 is a configuration diagram of a ring roller mill to which the present invention is applied.

FIG. 14 is a cross-sectional view of a main part of a conventional example.

FIG. 15 is a sectional view of a main part of a conventional example.

FIG. 16 is a cross-sectional view of a main part of a conventional example.

[Explanation of symbols] 1 crushing raw material 2 raw material supply pipe 3 rotary table 4 crushing roller 5 roller rotating shaft 6 roller arm 7 arm lever 8 pressurizing device 9 journal 10 stopper 11 housing 12 throat vane 13 hot air 14 splitting segment of the crushing ring ( Inner) 15 Split segment of crushing ring (outer) 16 Fibrous filler 17 Holding plate of divided segment 18 Joining member 19 Holding plate of divided segment 20 Joining member 21 Table rotating shaft 22 Rotating classifier 23 Dam ring 24 Product dust discharge duct

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroaki Kanemoto 6-9 Takaracho, Kure-shi, Hiroshima Babkotuku Hitachi Co., Ltd. Kure Factory (72) Yoshinori Taoka 6-9 Takaracho, Kure-shi, Hiroshima Babkotsu Hitachi Stock Company Kure Factory (72) Inventor Tadashi Hasegawa 6-9 Takaracho, Kure City, Hiroshima Prefecture Babkotuku Hitachi Co., Ltd. Kure Factory (72) Inventor Hiroshi Yuasa 6-9 Takaracho, Kure City, Hiroshima Prefecture Babkotuku Hitachi Co., Ltd. Kure Factory

Claims (3)

[Claims] 1. A crushing ring segment which is mounted on a rotary table which rotates around a vertical axis on a horizontal plane and which is divided in the circumferential rotation direction of the rotary table, and a peripheral surface is pressed against the outer peripheral side upper surface of the crushing ring segment. In a crushing device for crushing a raw material with a plurality of crushing rollers rotating in a state of being rotated or a plurality of crushing balls rolling with an outer surface being pressed, each segment of the crushing ring is divided into a radial direction of a rotary table. On the other hand, the crusher is characterized by being divided into a plurality of parts. 2. The crushing device according to claim 1, wherein the connecting parts of the divided segment parts are formed in a concavo-convex shape so that the segment parts are meshed with each other. 3. The crushing device according to claim 1, wherein a buffer body made of a fibrous substance or the like is press-fitted into the connecting portion gap of the divided segment parts.