JPS6223552Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an apparatus for pulverizing and classifying materials to be pulverized, such as coal, and particularly relates to a pulverizing and classifying apparatus that reduces wear on the classifying section.

Figures 1a and b show a ball mill for crushing and classifying coal. In the figure, the raw coal to be crushed falls down the coal feed pipe 21 and reaches the crushing section 22.
It is pulverized by the lower roller 24 and the ball 23 which rotates as the roller 24 rotates. The pulverized coal rises inside the ball mill body by air A, which dries the coal and transports the air, and passes through the guide vane 2.
5. In the guide vanes 25, the pulverized coal is given a swirling force, and the pulverized coal is classified in the mill hopper 1. In other words, coarse coal that requires re-pulverization descends while swirling around the peripheral wall of the mill hopper 1, falls into the crushing section 22, and is re-pulverized, while pulverized coal rises inside the mill hopper 1 together with air A.
Transported by airflow to a predetermined location. The vane 25 and hopper 1 that classify the pulverized coal are subject to severe wear due to the friction of the pulverized coal, and therefore anti-wear measures are required. FIG. 2 shows an example of this anti-wear measure. In the figure, a shows a countermeasure applied to the mill hopper 1, in which a large number of hardened build-up beads 5 are formed in the direction of the generatrix of the mill hopper 1, thereby forming a layer of pulverized coal on the inner circumferential wall of the mill hopper to reduce wear. It is configured to allow b shows the state in which this bead 5 is formed on the guide vane 25. However, this method requires a long time for welding work, and furthermore, it is difficult to form the desired pulverized coal layer, and there are problems in that sufficient wear resistance cannot be exhibited.

FIG. 3 shows a structure in which a wear-resistant block plate 6 made of a wear-resistant steel plate or ceramic is attached to the hopper surface by direct insertion. In the case of wear-resistant steel plates, the top and bottom can be fixed to the hopper surface by spot welding 7, but in the case of ceramic plates, holes must be drilled and bolts must be used to fix them. On the other hand, ceramics have sufficient wear resistance, but steel plates do not have sufficient wear resistance. Next, the hopper surface is curved, and the block must also have a shape that corresponds to this.While it is easy to manufacture wear-resistant steel plates that fit this curved surface, it is extremely difficult to manufacture ceramics. It is not possible to process items that are too large. In other words, there are advantages and disadvantages no matter which material is used.

Figure 4 shows a procedure for directly attaching ceramic pieces to a steel plate, which compensates for the shortcomings of the method shown in Figure 3. By using ceramics, wear resistance is improved and the molding of ceramics is simplified. The structure is designed to reduce manufacturing costs. That is, as shown in FIGS. 4a to 4d, a ceramic piece formed into a rectangular, triangular, circular, etc. shape, that is, an uncurved plate, is glued to the periphery of the ceramic piece using a heat-resistant adhesive 9 as shown in figure 4e. They are directly bonded to the inner circumferential wall of the hopper 1 with a space between them. According to this method, since the ceramics are small pieces, it is possible to attach the ceramic plate even if the inner peripheral wall of the hopper is curved.
Moreover, since it is a small piece of flat plate, the manufacturing cost is also relatively low. However, heat-resistant adhesives can be heated up to 100℃~300℃ after bonding.
℃, but in the method of directly bonding the ceramic plate to the mill hopper, the entire hopper must be heated, making post-heat treatment very difficult, and compared to attaching the steel plate by spot welding, it requires more work. Efficiency will deteriorate significantly.

The purpose of this invention is to eliminate the above-mentioned problems and provide a crushing and classifying device with a wear-resistant structure that maintains high wear resistance by using ceramic plates and greatly improves the work efficiency of attaching ceramic plates. It's about doing.

In short, this idea involves bonding small pieces of ceramic to a metal plate formed into a block with a heat-resistant adhesive or the like with a gap of 11 between them around the periphery, and spotting the metal plate to which the small pieces of ceramic have been glued onto the inner peripheral surface of the mill hopper. This is a crushing and classifying device that can be installed by means such as welding, eliminating the need for post-heat treatment in the mill hopper, work for attaching small pieces in the mill hopper, etc., and greatly improving workability.

The purpose of providing the interval 11 between the circumferential edges of the small pieces is that the pulverized coal that is flowing along with the swirling flow and scraping the surface of the ceramic is drawn into the groove by the small vortex flow in the groove, and the pulverized coal is drawn into the groove by the small swirl flow in the groove. In addition to protecting the buried mill hopper steel plate from this abrasion, it also acts as a buffer zone that absorbs the difference in thermal expansion between the mill hopper steel plate and the small ceramic pieces.

Examples of this invention will be described below with reference to the drawings.

In FIGS. 5a to 5d, reference numeral 10 denotes a block-shaped metal plate, which is curved to match the curved surface of the mill hopper when used in a mill hopper. To this metal plate (for example, an iron plate made of carbon steel), a flat ceramic piece 8 formed into a rectangular, triangular, etc. shape is adhered with a heat-resistant adhesive 9 as shown. After these ceramic pieces 8 are bonded to each block-shaped metal plate 10 with a heat-resistant adhesive 9, a post-heat treatment is performed for each metal plate.

The post-heat treated block metal plates 10 are each attached to the inner surface of the mill hopper by spot welding 7 in the same manner as in the conventional method shown in FIG. 6th
The figure shows the metal block attached to the inner surface of the hopper 1 in this manner.

If formed in this manner, bonding and post-heat treatment of the ceramic plates can be freely performed for each block at a location other than the mill hopper 1, and the blocks can be easily attached to the mill hopper by spot welding. In addition, the part of the mill hopper that is subject to severe wear is approximately one height from the upper edge of the hopper, and by attaching a block-shaped metal plate to this part, most of the objectives can be achieved.

The above explanation has focused on attachment to the mill hopper, but it is also possible to attach it to the guide vane in the same way, and it can also be installed in a wide range of areas other than the illustrated crushing and classifying device where wear resistance needs to be increased. .

By implementing this idea, the wear resistance of the device can be maintained at a high level by attaching the ceramic plate, and since the small pieces of ceramic can be bonded and post-heat treated outside the hopper, the work of attaching the ceramic plate can be facilitated. , ceramics are small pieces that form grooves at intervals around their periphery, and pulverized coal fills these grooves to protect the steel plates in the gaps from wear, and also serves as a buffer zone for thermal expansion of the mill hopper. It has the following effects.

[Brief explanation of the drawing]

Figure 1 a is a cross-sectional view of the crushing and classifying device, b is A-A
Figure 2a is a perspective view of the mill hopper, Figure 3b is a perspective view of the guide vane, Figure 3a is a perspective view of the mill hopper with wear-resistant blocks, Figure 3b is a perspective view of the mill hopper.
is a partially cut away perspective view of figure a, Figures 4a and 4b are partial views of the inner wall surface of the hopper with small ceramic pieces attached, figure e is a cross-sectional view taken along line B-B of figure a, and Figure 5. Figures a to c are perspective views of metal blocks with small ceramic pieces attached, and d is C of figure a.
6 is a partially cutaway perspective view of the mill hopper to which the metal block shown in FIG. 5 is attached. 1...milhopper, 7...spot welding, 8...
... Ceramics small piece, 9 ... Heat-resistant adhesive, 10
...Block-shaped metal plate, 11 ... intervals.

Claims (1)

[Claims for Utility Model Registration] 1. A plurality of block-shaped metal plates formed to closely engage with the inner surface of a mill hopper for classifying materials to be crushed, with small pieces of ceramics adhered in advance along the periphery thereof at intervals, These block-shaped metal plates are attached to the inner surface of the mill hopper by welding to form a ceramic lining on the inner surface of the mill hopper, thereby improving wear resistance. 2 Utility Model Registration Scope of Claim 1. The crushing and classifying device with improved wear resistance as set forth in claim 1, in which a block-shaped metal plate to which the ceramic pieces are adhered is also attached to a guide vane attached to the upper end of the mill hopper.