JPS5992038A - Crushing ring - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grinding ring mounted on a rotary table VC of a coal grinding mill, in particular a grinding ring consisting of a ductile substrate and a highly wear-resistant surface layer. More particularly, the present invention relates to a grinding ring comprised of a highly ductile substrate and a Krogmu carbide alloy covering the top surface of the substrate to form a highly wear resistant roll contact surface.

Coal grinding mill and pulverized coal, for example, US Pat.
Evening and IQO issue and 3rd. As disclosed in U.S. Pat. No. 3,333,333, a housing for a bowl mill includes a housing in which a rotary table is rotated by a vertical shaft. The rolls, which are the grinding elements, are urged downwardly by springs or hydraulic means towards the top of the rotary table. The coal to be crushed is fed between the surface of the roll and the surface of the table and is crushed. Air is introduced into the housing and conveys the crushed coal to the desired size and removal from the unung.

To explain in more detail, the rotary table straddle bowl ta,
The top surface provides the grinding working surface by the grinding ring, which is called the "male ring". This grinding or male ring has a track that is in direct contact with the surface of the roll that is biased downwardly. This grinding ring is made independently and fixed on a rotating table. The grinding ring is exposed to very high wear because it cooperates with the surface of the grinding rolls to grind the coal.

Therefore, various methods have been developed for a long time to completely eliminate the wear problem of the grinding rings, and as a solution, improvements have been made to the base bodies and surfaces of these grinding rings.

At the beginning of its development, crushing rings were formed from a single piece made from forged steel. Such forged steel grinding rings have satisfactory strength and ductility, but their wear resistance has not always been satisfactory.

Therefore, according to the subsequent development, the crushing ring is N1
- Made of a single piece made from hard (Nj -hard), its wear resistance is improved. This N]-hard material is a material well known as a special alloy containing a large amount of nickel as a component. The grinding ring formed from a single member of the N1-node has satisfactory wear resistance t't', '
&' [However, unfortunately, it has been found that the brittleness is not necessarily satisfactory as it is brittle, and there is a problem that it is easy to collapse and be destroyed.

In order to deal with the problem of N1-...-do being easily destroyed, the crushing ring is formed into several parts,
As a result, the problem of easy breakage of N]-hard materials has been solved to some extent, and progress has been made in the development thereof. However, with such a divided crushing ring, each divided part must be fixed on a rotary table made of ductile material, which makes installation complicated, and there is a risk of damage due to breakage of each part. There was a problem that the number of replacements increased.

Therefore, continuous development efforts are being made to solve the material problems while forming the crushing ring from a single member without dividing it.

However, the ductility required for such a grinding ring is
It is clear that it can only be obtained by steel. Additionally, the base of a grinding ring made of such steel must be coated with an alloy that has satisfactory wear resistance and must be made of ductile material such that it can be easily mounted on a full rotating table or bowl. It has to be something.

The present invention was made in view of the above circumstances, and the alloy forming the entire wear-resistant surface of the single substrate of the grinding ring is preferably made of chromium λ, S%*.
W element "-'%, manganese 6.3% and silica/,
Contains t4f. This alloy is bonded to the upper surface of the cast metal base of the grinding ring by welding or by instant bonding in powder form.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings, but first an outline of a coal crushing mill will be described.

The rotating bowl or table of a coal grinding mill has a surface that is in direct contact with the balls or rolls that cooperate with the table to grind the coal to the desired size. This surface ha. It is formed by a separate grinding ring called the male cylinder °'.

This crushing or male ring may, for example, have an outer diameter of 23 I
Approximately I cm (/ 00 in.) (7) Thick @ T ant, Mff-50, g cm (Equipped with a track that has a width of about θ inch and comes into direct contact with the roll. Desired The pulverized coal is conveyed upwardly inside the mill by air and exits the mill.A device for feeding all the coal to be crushed, a device for recirculating the coal for further pulverization, and a device for recirculating all the pulverized coal. Since the apparatus for transporting by air is not directly related to the gist of the present invention, a detailed explanation thereof will be omitted.

The gist of the invention lies in the structure of a grinding ring attached to a rotary table. Therefore, the device for attaching the grinding ring to the top surface of the rotary table is also not directly related to the gist of the present invention, so a detailed explanation thereof will be omitted.

Now, one embodiment of the present invention will be described with reference to FIG. 7. The coal and pulverizing mill include...Using/.

Housing/C, internal frame member on which the motor connected to the pinion gear λ is mounted 7. W 1~.

The pinion gear λ meshes with a gear on a vertical shaft 3, and a rotating bowl or table tag is mounted on the upper end of the vertical shaft 3. One or more grinding rolls S, according to the embodiment illustrated here, are mounted on trunnions and biased downwardly toward a surface provided by table lvc.

The chute is connected to a coal supply located outside the mill and directs the coal to be ground from this supply to the central part of the table. This coal to be crushed is introduced and crushed by centrifugal force between the surface of the roll 5 and the surface of the crushing ring/λ provided by the invention on the table q. When the coal is crushed to the desired size, air enters the mill through the openings 1] 10 and then flows upwardly to transport the crushed coal into the fine particles.

Thus, the crushing or male ring/2 of the present invention is attached to the upper surface of the rotary table g by suitable means. The contact surfaces of the ring/2 and the table q are made very large so that the base body of the ring/2 does not bend excessively and cause cracks due to the extremely large force applied by the roll S. It is precisely adapted to. The base of ring/2 is made of cast steel to meet the ductility required for such a ring, while the base of ring/2
The upper surface of 2 is made of a wear-resistant material that can withstand the coal crushing action that takes place between this upper surface and the surface of the roll t(7).

FIG. 1 is a partially enlarged sectional view of the crushing ring shown in FIG. Shown in full details.

The base isB of the crushing ring/a, and its lower surface/A
(The upper surface of the table q (see FIG. 1) comes into contact with the upper surface of the base 15. A wear-resistant material /7 is bonded to the upper surface of this base body 15. Thus, the entire grinding ring has a novel structure according to the present invention.

The gist of the present invention is, as mentioned above, that the grinding ring/-! This is due to the structure of the grinding ring, and not to the method of manufacturing such a grinding ring. The steel base 15 of the grinding ring/2 is covered on its upper surface with a wear-resistant material, alloy 77. This alloy 17 is preferably chromium u? Contains 0g% of carbon, 3% of manganese, and silica/J%. Alloy 77 can be attached to the top surface of substrate/S by welding, or alloy 77 can be attached in powder form to the top surface of substrate/S by "sintering." As shown in Figure 1, it is formed to have a surface or track [a1.g] that contacts the surface of the rotor (see figure) and has a full angle.

Although the actual case of the present invention has been described above with reference to all the attached drawings, the present invention is in no way limited to this specific example, and various modifications can be made without departing from the scope of the present invention. Of course, transformation is possible.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of the main parts of a coal crushing mill that uses a rotary table equipped with a crushing ring according to the present invention, and FIG. 2 shows an example of the crushing ring according to the present invention shown in FIG. It is a partially sectional view. /II fist mill housing, co-pinion gear, 3.
・Vertical shaft, ri・0 rotation table, 5...roll
6...Shoot, 10..."Z Qi 4 person 1gF1 mouth,
//... Outlet duct, /2... Grinding ring, /S... Substrate, /6-- Its lower surface, /7... Alloy, 7g... Its M surface in contact with the roll.

Claims (1)

[Claims] A crushing ring mounted on a rotary table of a coal crushing mill, comprising a base made of cast steel and fixed to the upper part of the rotary table, and a crushing ring made entirely of cast steel.