JP2001009303A - Roller mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously cut coarse powder strayed into during finely classifying of a product by making easy an inspection and repair operation of a classifier mounted in a roller mill. SOLUTION: A classification part comprises a cylindrical dashboard 14 fixed to a ceiling 15, an outer peripheral side stationary fin 9 and an inner peripheral side rotary fin 11 which are concentrically arranged via the dashboard 14, and a cone open to a rotary table 3 by being supported by a lower end of the stationary fin. A part of the stationary fin 9 is segmentalized to be made detachable, and a manhole 25 capable of being opened and clossed is provided in the cone 10. When the classification part is inspected and repaired, the manhole 25 and a part of the stationary fin 9 are opened to secure an extrance and exit. An operator enters the inside of the classification part from the entrance and exit thereof, and executes the inspection repair operation concerning to the classifier such as the stationary fin 9, the rotary fin 11 or the like as well as an exchange operation for a wearing plate 14b of the dashboard 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller mill for finely pulverizing a solid fuel or a solid raw material such as coal, and more particularly, to a technique for maintaining and inspecting a classifier mounted in the roller mill or replacing parts.

[0002]

2. Description of the Related Art In coal-fired boilers, low-pollution combustion (low NO
x, low-ash unburned matter) and wide-area load operation, and accordingly, pulverized coal machines (mills) are also required to have high grinding performance and reliability. Recently, as a type of mill for finely pulverizing lump materials such as coal, cement raw materials, or new raw materials, rigid roller mills that use a rotating table and a plurality of tire-type rollers to perform pulverization have been widely used. In particular, it has solidified its position as a representative model in Japan.

FIG. 7 is a diagram showing the configuration of a general roller mill. The rotary table 3 has a substantially circular truncated shape and is disposed below a cylindrical casing 8. A plurality of crushing rollers 4 are provided which rotate by applying a load to the position equally divided in the circumferential direction by a hydraulic pressure or a spring. The turntable 3 is driven by a motor (not shown) and rotates at a low speed via a speed reducer. Hot air (primary air) 6 which is also a part of the combustion air is guided through a duct to a lower portion of the casing 8, and the hot air 6 is supplied to a throat vane 7 of an air throat between the rotary table 3 and the casing 8. Blowing through the gap. A feeder supply pipe (center chute) 2 and a coal feed pipe 13 are provided in a distributor 12 at the upper end of the casing 8, and a classifier is provided below the feeder pipe. This classifier is provided with stationary fins 9 arranged in a cylindrical shape on the outside, a conical cone 10 supported by the lower end of the fixed fins 9 and opening toward the rotary table 3, and a rotating direction on the inside. And a rotating fin 11 in which a fin row rotates.

The raw material 1 is supplied from the raw material supply pipe 2 at the upper part of the casing 8 to the center of the rotary table 3 and moves to the outer periphery on the rotary table 3 by drawing a spiral locus by centrifugal force. It is caught between the crushing race 5 of the rotary table 3 and the crushing roller 4 and crushed. The powder and granules after being pulverized in this manner are dried while rising in the casing 8 by the hot air (primary air) 6 blowing up from the air throat. The granular material transported to the upper part of the casing 8 falls from a coarse material by gravity (primary classification) and is pulverized again in a pulverizing unit. The slightly fine powder that has passed through the primary classifier is classified again by a classifier provided at the upper part of the casing 8. In this classifier, a swirl is added to the mixed flow of the granular material and the airflow by the fixed fins 9,
By performing centrifugal classification with the inner rotating fins 11, only fine particles are transported together with the airflow through the coal feeding pipe 13, and in the case of a coal-fired boiler, are sent to a burner for pulverized coal combustion. The coarse powder larger than a predetermined particle size, which has been repelled by the rotating fins 11, falls by gravity onto the rotating table 3 through the cone 10, and is pulverized again with the raw material 1 just supplied into the mill. In this way, in the roller mill, pulverization and classification are repeated, and product fine powder is produced.

[0005] In such a roller mill, if the amount of coarse powder in the pulverized coal produced by the classifier is reduced, the burnout is accelerated, the unburned content in the ash is reduced, and the boiler furnace can be made compact. A classifier that cuts coarse powder in pulverized coal has been proposed.

FIG. 8 is an explanatory view showing an example of such a classifier. This type of classifier has a cylindrical partition plate 14 interposed between a fixed fin 9 and a rotating fin 11. The partition plate 14 is fixed downward from the ceiling plate 15 of the mill. As indicated by arrow 16, casing 8
The granular material rising in the inside passes through the space between the fin rows of the fixed fins 9 and flows into the secondary classification section, and collides with the partition plate 14 in the secondary classification section, whereby the coarse powder 17 is moved downward. flow,
The fine powder 18 flows to the rotating fin 11 side. The coarse powder 17 flows down in the cone 10 and is pulverized again in the pulverizing section. The fine powder 18 is centrifugally classified by the rotation of the rotating fins 11, and the coarse powder is pulverized down the cone 10 and re-pulverized. After the flow of the fine powder 18 collides with the partition plate 14,
Once the direction is changed downward, the gap between the rotating fin 11 and the ceiling plate 15 (where the seal ring 19 is provided) is avoided, and the coarse powder 17 is prevented from being mixed during product differentiation. Can be reduced.

[0007]

As described above, the cylindrical partition plate 1 is provided between the fixed fin 9 and the rotating fin 11.
Although the effect of coarse powder cutting can be remarkably enhanced by providing the intervening member 4, the ascending powder particles collide with the partition plate 14, and the lower outer surface portion of the partition plate 14 is worn over time. If the partition plate 14 is worn out by use for a long period of time, the rising and flowing powder will no longer collide with the partition plate 14, but of course the effect of coarse powder cutting will also disappear. In short, the partition plate 14 is a consumable and needs to be updated periodically.

However, since this kind of partition plate 14 is located between the fixed fins 9 and the rotating fins 11 and is fixed to the lower surface of the ceiling plate 15 of the mill, there is a problem that it is difficult for an operator to access during inspection and repair. appear. It is also possible to separate the upper part of the casing 8 from the lower pulverizing part together with the classifying part and remove the fixing fins 9 and the cones 10. However, such a method is an extremely large-scale operation, so that maintenance at the time of updating is required. To make it easier, some ingenuity is needed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to improve the maintainability and workability while effectively cutting coarse powder mixed during product differentiation. An object of the present invention is to provide a roller mill capable of keeping the overall operation cost low.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a fine powder produced by a classifier is provided by interposing a cylindrical partition member between a fixed fin row and a rotating fin row of a classifier mounted in a roller mill. In addition to making it possible to effectively cut coarse powder mixed in the coal, there is no entrance and exit that can open and close at least a part of the cone member or fixed fin.If the partition member is worn out over a long period of use, the entrance and exit during inspection and repair To allow the worker to approach in the circumferential direction of the partition member.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a roller mill according to the present invention, a pulverizing section comprising a rotary table and rollers, a classifying section disposed above the pulverizing section, and a cylindrical casing containing the pulverizing section and the classifying section are included. In a roller mill that pulverizes the solid raw material in the pulverizing section and conveys the pulverized raw material to the upper side of the casing by the action of an air current, and classifies the pulverized raw material in the classification section to produce product fine powder, the classification section includes the A cylindrical partition member fixed to the ceiling plate of the casing, an outer peripheral side fixed fin and an inner peripheral side rotating fin arranged concentrically via the partition member, and joined to a lower portion of the fixed fin. A substantially cone-shaped cone member having a lower end opening toward the rotary table, and an entrance capable of opening and closing at least a part of the cone member or the fixed fin. , Worker opens the doorway during inspection repair is configured to close the circumferential direction of the partition member.

The entrance is preferably formed of a manhole or a detachable segment. In this case, when the manhole is opened or the segment is removed at the time of inspection and repair, and the operator enters the inside of the classifying section, the entire circumference of the partition cylinder is removed. Can work on the department.

The entire partition member worn during the inspection and repair may be replaced. However, since the portion where the particle group collides and wears is the lower outer surface of the partition member, the lower portion or lower outer portion of the partition member may be replaced. It is preferred that the surface be a wear ring plate as a consumable member, and that the wear member be worn at the time of inspection and repair be replaced with a new wear ring plate to regenerate the partition member.

Further, the wear ring plate may be a segment member divided in the circumferential direction of the partition member. Such a wear ring plate is suitable for use in a large roller mill.

[0015]

Embodiments will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a roller mill in a cross section in a longitudinal direction, and FIG.
Is an explanatory view showing a mounting structure of a partition plate provided in a classifier, FIG. 3 is an explanatory view showing a worn state of a wear plate, FIG. 4 is an explanatory view showing an attached state of a wear plate to the partition plate, and FIG. FIG. 6 is an explanatory view schematically showing the inspection and repair work of the partition plate. FIG. 6 is an explanatory view schematically showing the loading or unloading work of the wearing plate.
Are given the same reference numerals.

As shown in FIG. 1, a raw material 1 is supplied into a mill through a raw material supply pipe (center chute) 2, falls on a rotary table 3, and is conveyed outward by the centrifugal force of the rotary table 3. , Are compressed and crushed by the crushing roller 4. The crushing roller 4 includes a roller bracket 22 that supports the shaft of the crushing roller 4 from the outside, a pivot 24 that is a support shaft of a pendulum operation of the crushing roller 4, and a pressing frame 23 that presses these from above.
And the grinding load is transmitted. The raw material broken in this crushing section is blown up by hot air 6,
Some coarse materials fall by gravity (gravity classification or primary classification), and fine ones flow into a classification part mounted above the casing 8.

The classifying section includes a stationary fin 9 arranged in a cylindrical shape on the outside, a conical cone 10 supported by the lower end of the fixed fin, and having a lower end opening toward the rotary table 3.
A fin row arranged inside in the rotation direction is constituted by a rotating fin 11 that rotates, and a hoist suspension hook member 28 is provided between the fixed fin 9 and the casing 8. The outer fixed fins 9 are fixed so as to be inclined in the circumferential direction, so as to add a swirl to the mixed flow of the particles and the air current. In the present embodiment, a part of the fixed fin 9 is segmented to be detachable (broken line 27 in FIG. 1).
As shown later, a portable temporary scaffold is inserted, or an operator can enter and exit the classifier. The inner rotating fins 11 perform centrifugal classification, and only fine particles are sent to the pulverized coal burner in the case of the pulverized coal fired boiler through the coal feeding pipe 13 together with the airflow. The coarse powder repelled by the rotating fins 11 flows down on the inner wall of the cone 10 and falls on the rotating table 3 to be reground. A manhole 25 that can be opened and closed is provided in a part below the cone 10,
A footrest 26 is provided inside the cone 10. At the time of inspection and repair, the worker can enter the inside of the cone 10 from above the pressurizing frame 23 by opening the manhole 25, and use the footrest 26 to
You can go up and down inside.

Outer fixed fin 9 and inner rotating fin 1
1, a cylindrical partition plate 14 is interposed therebetween. As shown in FIG. 2, an upper end of the partition plate 14 is a flange portion 14c, and the flange portion 14c is fixed to a fixing member such as a bolt. The upper end of the partition plate 14 is fixed to the ceiling plate 15 by being mechanically joined to the ceiling plate 15 at 30. The ceiling plate 15 inside the flange portion 14c has
The backup locking member 29 is fixed using a welding stopper or the like in order to avoid the trouble of the partition plate 14 being dropped. The locking member 29 is provided with an opening 29a for inserting a bolt head of the fixing member 30 or a screwing device from below. Further, a cylindrical plate-shaped wear plate 14b is fitted and fixed in a concave portion 21 provided on the lower outer surface of the partition plate 14, and the wear plate 14b can be replaced with a new one during inspection and repair. .

That is, the lower outer surface of the partition plate 14
As shown in FIG. 3 (a), the wear ring plate 14b fitted into the classifying portion is worn and deformed over time, as shown in FIG. The wear of the wear ring plate 14b is more remarkable toward the lower end, because the wear due to the collision of the particle groups is more severe near the lower end of the partition plate 14. If the worn ring plate 14b is continued to be used as it is, the wear ring plate 14b becomes thinner, and the partition plate 14 serving as a back support is also damaged, so that the original function of the partition plate 14 cannot be performed. Therefore, when the wear plate 14b is worn, as shown in FIG. 3B, the partition plate 14 can be regenerated by replacing the worn wear plate 14b with a new one.

In the case of a small-sized roller mill, the above-mentioned partition plate 14 has an integral cylindrical structure or a butt structure of a half cylinder which is equally divided in the circumferential direction, and a wear ring plate 14b having the same structure is used as the partition plate 14. Although it can be mounted, in the case of a large roller mill, as shown in FIG. 4, it is desirable that the partition plate 14 and the wear ring plate 14b are each divided into a plurality of segments in the circumferential direction. In this case, each new wear ring plate 14b segmented at the time of inspection and repair may be fitted into the recess 21 of the partition plate 14 and fixed. When the partition plate 14 and the wear ring plate 14b are segmented in this manner, a large roll Since molding is not required, the manufacturing cost of the partition plate 14 and the wear ring plate 14b can be reduced, and the soundness inspection of the partition plate 14 and the work of attaching and detaching the wear ring plate 14b can be facilitated.

When performing the inspection and repair work on the classifying section, first, as shown in FIG. 5, the manhole 25 which is transmitted through the stepladder 32 provided between the roller bracket 22 and the casing 8 or the manhole 25 opened in the cone 10 and the cone is used. 1
0, each of the workers 3
3,34 enters the classification section. Thereafter, a part of the segmented fixed fins 9 is removed to secure an entrance (see reference numeral 9a), and a temporary scaffold 35 is passed between the fixed fins 9 and the rotating fins 11, whereby the worker 36 is classified. Perform inspection and repair work on parts. In this case, the worker 36 performs an inspection and repair work on the classifier such as the fixed fins 9 and the rotating fins 11, including a work of replacing the wear ring plate 14 b of the partition plate 14. When the wear ring plate 14b is worn out, as shown in FIG. 6, the hoist 38 is fixed to the hoist suspension hook member 28, and the wear ring plate 14b to be replaced is lifted by the wire 39b, and the hoist 38 is lifted from the entrance 9a. By loading or unloading, the wear plate 14b worn out as described above is replaced with a new one, and the partition plate 14 is regenerated.

In the above embodiment, when inspecting and repairing the classifying section, the manhole 25 provided in the cone 10 is opened or a part of the segmented fixed fins 9 is removed, so that the worker can access these entrances. Can easily reach the classifying section from the above, and even in the classifying section having a small working space, a series of maintenance work such as inspection, repair, parts replacement, etc. of the entire classifier including the partition plate 14 can be smoothly performed. . Therefore, it is not necessary to remove the upper casing in which the classifier is inserted and to attach and detach the two fins 9 and 11, thereby shortening the time required for inspection and repair, reducing costs, and ensuring the safety of the operation. it can. In addition, since a part of the partition plate 14 where wear occurs is formed as a replaceable wear ring plate 14b,
The operation of reproducing the partition plate 14 can be easily performed.

[0023]

The present invention is embodied in the form described above and has the following effects.

Since a cylindrical partition member is interposed between the fixed fin row and the rotary fin row of the classifier mounted in the roller mill, coarse powder mixed into the pulverized coal produced by the classifier is effectively cut. In addition, since the operator can easily reach the inside of the classifier at the time of inspection and repair, maintenance and workability, including the work of regenerating worn partition members, are improved, and overall operating costs are reduced. It can be kept low.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a roller mill according to an embodiment in a longitudinal section.

FIG. 2 is an explanatory view showing a mounting structure of a partition plate provided in a classifier.

FIG. 3 is an explanatory view showing a wear state of a wear ring plate.

FIG. 4 is an explanatory diagram showing a state in which a wear ring plate is attached to a partition plate.

FIG. 5 is an explanatory view schematically showing inspection and repair work of a partition plate.

FIG. 6 is an explanatory diagram schematically showing a loading or unloading operation of a wear ring plate.

FIG. 7 is a configuration diagram of a roller mill according to a conventional example.

FIG. 8 is an explanatory diagram of a classifier proposed earlier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material 2 Raw material supply pipe 3 Rotary table 4 Crushing roller 8 Casing 9 Fixed fin 9a Doorway 10 Cone 11 Rotary fin 14 Partition plate 14b Wearing plate 15 Ceiling plate 21 Depression 25 Manhole

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroaki Kanemoto 3-36 Takara-cho, Kure-shi, Hiroshima Pref. Inside Kure Research Laboratories Co., Ltd. (72) Inventor Nobuyasu No. 3-36 Takara-cho, Kure-shi, Hiroshima Pref. (72) Inventor Hideo Mitsui 6-9 Takaracho, Kure-shi, Hiroshima Prefecture Babkotsuk Hitachi, Ltd. Kure Factory (72) Inventor Kotaro Sakota 6-9 Takaracho, Kure-shi, Hiroshima Prefecture Babkotsuk Hitachi, Ltd. Kure Factory (72) Inventor Takashi Harada 6-9 Takara-cho, Kure City, Hiroshima Prefecture Inside Babkotsuk Hitachi Kure Factory (72) Inventor Tadashi Hasegawa 6-9 Takaramachi Kure City, Hiroshima Prefecture Babkotsuk Hitachi Kure Factory F-term ( Reference) 4D063 EE03 EE12 EE21 GC05 GC12 GC16 GC32 4D067 EE01 EE23 EE45 GB02

Claims (4)

[Claims] 1. A crushing section comprising a rotary table and rollers, a classifying section provided above the crushing section, and a cylindrical casing including the crushing section and the classifying section,
In a roller mill that pulverizes the solid raw material in the pulverizing section and conveys the pulverized raw material to the upper side of the casing by the action of an air current, and classifies the pulverized raw material in the classification section to produce product fine powder, the classification section includes a ceiling plate of the casing. A cylindrical partition member fixed to the outer peripheral side fixed fins and an inner peripheral side rotating fin arranged concentrically via the partition member; A substantially conical cone member that opens toward the table, and an entrance that can open and close at least a part of the cone member or the fixed fin. A roller mill characterized by being configured to be able to approach in the circumferential direction of a partition member. 2. The roller mill according to claim 1, wherein the entrance comprises a manhole or a detachable segment. 3. The wearable plate according to claim 1, wherein a lower part or an outer surface of the lower part of the partition member is a wear ring plate as a consumable member, and the wear ring plate worn at the time of inspection and repair is replaced with a new wear ring plate. A roller mill characterized by regenerating a partition member by means of a roller mill. 4. The roller mill according to claim 3, wherein said wear plate comprises a segment member divided in a circumferential direction of said partition member.