JPS6061045A - Crusher for preventing crushed substance - 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 pulverizer, and more particularly to a pulverizer configured to significantly reduce the amount of pulverized material falling into the 6F section of the device.

Due to recent changes in the fuel situation, the number of large boilers for business use such as large boilers for thermal power plants that use coal as fuel is increasing. Ru. By pulverizing the coal in this way (for example, 70% or more of the amount that passes through 200 meshes), the surface area of the coal per unit amount increases, improving combustibility, and since it burns in a short time, controllability is also greatly improved. There is an advantage to doing so.

FIG. 1 shows a pulverizer called a vertical ball mill among the coal pulverizers. Coal C to be pulverized falls through the coal feed pipe 8 of the pulverizer main body 1 and reaches the pulverizer. The crushing section has an upper fixed ring 6 to which a pressing force is applied by the pressurizing device 4. Lower roller wheel 9 rotated by drive device 41. It is formed from a plurality of crushing balls 7 arranged between the upper fixed ring 6 and the lower roller 9 and rolling with the rotation of the lower roller 9.

The coal that has reached the crushing section is moved to the crushing ball arrangement section by the centrifugal force generated by the rotation of the lower roller 9 and is crushed. The pulverized coal is supplied through the air port 17 and the perforated plate 15
The air (usually high temperature air is used to dry the coal) that blows out of the machine rises inside the device, and during this time, large-diameter particles fall into the crushing section as shown by arrow 14, where they are primarily classified, and the remaining crushed coal is The airflow containing the . In the classification f'fl, large-diameter particles descend through the classifier due to the swirling of this airflow, fall into the crushing section, and are re-pulverized, and the pulverized coal flows into the pulverized coal pipe 13 with the airflow and is airflow-transported to the burner. Ru.

Figures 2 and 3 show the structure of the perforated plate attached to the above device. Air injection holes are formed. The air injection hole is formed as a slit as shown in FIG. 3, and air is ejected from the slit 18 and the gap 19 between the perforated plate 15 and the lower roller 9. In this case, the slit 18 opens perpendicularly to the perforated plate 15 as shown in FIG. The pulverized coal forms a layer on the perforated plate 15, and is blown upward by the air injected from the perforated plate, but since it has vertical openings, the pulverized coal layer directly receives force fluctuations. , the air flow may momentarily stop, and at this time the pulverized coal will fall through the slit 18 to the bottom of the device. Due to the increase in the volume of the lower air chamber due to the recent increase in the capacity of the crushing equipment, the uneven flow within the air chamber becomes larger, and the amount of crushed coal that falls due to this uneven flow tends to increase.

Fallen coal is heated by high-temperature gas, making it dangerous and easily ignited, so it is cooled down by water spraying, etc. However, as the amount of falling coal is removed manually, it is difficult to remove the moisture-laden coal. will require a great deal of effort.

In addition, one method to reduce the falling of pulverized coal is to reduce the width of the slit and increase the injection speed, but this increases the pressure loss in the perforated plate and significantly increases the power cost of the blower. There is a problem with rising. Further, when the diameter is reduced, once the pulverized coal becomes clogged, it is difficult for the pulverized coal to fall down, resulting in the injection 11 being blocked for a long time.

This invention was constructed in view of the above-mentioned problems,
It is an object of the present invention to provide a crushing device that can effectively prevent falling of crushed materials without increasing the pressure loss of a perforated plate.

In short, in this invention, the air injection ports of the perforated plate are not formed into slits, but are divided into a large number of parts, and the air injection ports are opened diagonally with respect to the perforated plate.

Embodiments of the present invention will be described below based on the drawings.

In FIGS. 4 and 5, reference numeral υ20 is an air injection port formed on the perforated plate 15. In contrast to the conventional case where the injection port is formed in the shape of a long hole as a slit, the perforated plate A large number of small pieces are formed by cutting them short in the circumferential direction.

This air injection port 20 is formed 1,1 with respect to the perforated plate 15. Specifically, as shown in FIG. 5(A), the air injection ports 20 are formed and arranged at an angle of i:1 in the diametrical direction of the perforated plate 15. Reference numeral 20a denotes a wall surface of the injection port disposed opposite to this in the diametrical direction, and θJ indicates this inclination angle.

Next, in addition to being inclined as described above, the air injection ports may be further inclined with respect to the circumferential direction of the perforated plate 15.

FIG. 5(B) shows this state, where θ is the inclination angle in the circumferential direction, and 20b is the injection port wall surface located opposite in the circumferential direction.

FIG. 6 shows the results of an experiment conducted by the inventors, and is a diagram showing the relationship between the radial inclination angle 01 and the amount of falling coal when the circumferential inclination angle θ2 is changed. Note that falling coal is a relative value, so no units are given. Line diagram in the figure (
b) 02 is 0. In (b), θ2 is 5° and H is 0. is 10
The case of 200° and 200° is shown.

As is clear from the figure, the amount of falling coal is largely controlled by 0□, and it was confirmed that especially when θ becomes 10 or more, the amount of falling coal decreases significantly. Also, regarding 02, it is still 0
．． It can be confirmed that the amount of fall decreases as the value increases.
It was confirmed that the effect is particularly large when 02 is 10 or more. From this, it can be seen that a particularly large effect can be exhibited when both 0□ and 0□ are 10 or more.

In FIG. 7, the gap 19 formed between the lower roller wheel 9 and the perforated plate 15 is also formed in a shape 31, which is located obliquely at a constant angle θ with respect to the radial direction of the perforated plate.

Although the explanation has been given above using a coal pulverizer as an example, the invention is not limited to this, and relatively good results can be obtained even if the air injection holes are inclined in either the radial direction or the circumferential direction of the perforated plate.

By implementing this invention, it is possible to significantly reduce the falling amount of crushed material without increasing or decreasing the opening area of the entire air injection port, it is possible to prevent an increase in pressure loss in the perforated plate, and it is possible to reduce the power of the blower. It doesn't rise.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a ball mill, Fig. 2 is a sectional view of a perforated plate, Fig. 3 is a master view taken along line A-A in Fig. 2, and Fig. 4 is a perspective view of a perforated plate showing an embodiment of the present invention. Partial view, Figure 5 (A)
is a cross-sectional view taken along line E-B in Figure 4, (B) is a cross-sectional view taken along line O-0 in Figure 4, and Figure 6 shows the relationship between the inclination angle θ1 of the air injection port and the relative value of the amount of falling coal. A diagram showing the relationship, and FIG. 7 is a sectional view of a perforated plate showing another embodiment. 9...Lower roller 15...Perforated plate 20...Air injection port θ,...Inclination angle θ of the air injection port with respect to the radial direction of the perforated plate ,...Air injection port in the circumferential direction of the perforated plate (Lri oblique angle Fig. 1 ↓ Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] 1. In a device that injects gas from a perforated plate formed in an annular shape to air-transport the pulverized material to the upper part of the device, a large number of air injection ports are formed and arranged in the circumferential direction of the perforated plate, and each A pulverizer for preventing pulverized material from falling, characterized in that an air injection port is inclined in at least one of the radial direction and the circumferential direction of a perforated plate. 2. A pulverizer for preventing pulverized material from falling as set forth in claim 1, wherein the gap formed between the lower roller and the perforated plate is configured to be inclined in the radial direction of the perforated plate. .