JPS6064645A - Crusher - 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 for pulverizing coal and the like, and more particularly to a pulverizer that can significantly reduce the amount of crushed material falling to the bottom 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. In this way, by pulverizing the coal (for example, 70% or more of the amount passing through 200 mesh), the surface area of the coal per unit amount increases and the combustibility improves, and since it burns in a short time, controllability is also greatly improved. It has the advantage of being oriented toward

FIG. 1 shows a pulverizer called a vertical ball mill among the coal pulverizers. Coal a+-i 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 fed with air (
(Usually, the coal is also dried, so the air is at a high temperature) which causes it to rise inside the device. The airflow containing the pulverized coal is given a swirling force by the guide vanes 12 of the classifier 11 and flows into the classifier 11 . In the classifier 11, large-diameter particles descend through the classifier due to the swirl of this airflow, fall into the crushing section, and are re-pulverized, while pulverized coal flows into the pulverized coal pipe 13 along with the airflow and is carried along the airflow axis to the burner. .

FIG. 2 shows details of the air injection section of this crushing device. Reference numeral 42 denotes an air injection plate attached to the casing 1, which is formed into an annular shape so as to surround the outer peripheral edge of the lower roller 1tr9. 43 is a slit formed in this injection plate 42;
Air A flows through this slit 43, this injection plate, and the lower roller 9.
It is injected from the gap 44 between. In this case, an air vortex is generated on the back surface of the air jet plate 42, and a portion of the crushed coal is caught up in this vortex and falls to the lower part of the device 6'.

The upper surface of the air injection plate 42 has a layer of pulverized coal, and since air is injected from the lower part of the pulverized coal layer, this coal layer is fluidized like a fluidized bed. For this reason, if the thickness of the layer becomes uneven, the pulverized coal will fall to the bottom of the device mainly in the areas where the air jet flow velocity is slow.

In order to prevent the pulverized coal from falling, it is also effective to reduce the opening area of the slits and gaps and increase the air injection speed, but this method increases the power cost of the blower and is uneconomical.

The pulverized coal that has fallen to the bottom of the equipment is collected in a container placed at a predetermined location, and is cooled down by water spraying to prevent it from igniting.However, this water spraying increases the viscosity of the pulverized coal, which requires a great deal of effort to discharge. shall be. After all, it is better to have as little pulverized coal 111 falling to the bottom of the device as possible, and there is a demand for a device in which the amount of pulverized coal falling is small.

This invention satisfies the following two needs ('7.7) and provides a structure for a crushing device configured to significantly reduce the amount of crushed material such as coal falling to the bottom of the device. There is a particular thing.

In short, this invention focuses on the fact that the cause of pulverized coal falling is the generation of vortices caused by the airflow on the back side of the injection plate fixed to the casing side, and the air injection member having the air injection port is placed on the lower roller side. This is a pulverizer that is attached to a pulverizer and has a nozzle shape that does not generate eddy currents.

Examples of the present invention will be described below.

3 and 4 show a first embodiment of the invention.

Reference numeral 70 in the figure is an air injection member, which is located outside the lower roller 9.
lf+, and is formed into an annular shape so as to be placed in close contact with the outer peripheral edge of the lower roller as a whole. However, since the lower roller is usually a large one with a diameter of several meters, the air injection member is formed separately to facilitate its installation. 73 is a bolt that attaches the air injection member to the lower roller. Reference numeral 71 denotes an air injection passage formed in the air injection path r'rll, lo, and this passage may be formed not only in the vertical direction but also obliquely at a certain angle θ with respect to the horizontal direction. In this case, the inclination direction is the rotation direction C side of the lower roller 9.

Next, an inclined plate 8o is attached to the casing 1 side of the device. This inclined plate 80 basically has the same 6゛η configuration as the air injection plate 42 shown in FIG. 2, and is attached annularly to the inner circumferential wall of the casing. However, this inclined plate does not have a slit for air injection and is a blind plate. Note that 81 is an adjustment bolt for moving the inclined plate in and out of the lower roller 9 in the radial direction. The overlapping area of the inclined plate and the flange portion 70a of the air injection member 70 may be adjusted using the bolts, and an optimum position may be established to prevent the crushed coal from falling. In this case, the slanted plate is of course divided ((4) so that it can be taken in and out.

In the above tIIη-configured device, the air injection member wa rotates together with the lower roller 9, and during this time air is injected from the air passage 71 to air-transport the pulverized coal to the classifier.

In this case, since the air in each air passage 71 flows smoothly and is injected without creating a vortex, the amount of crushed coal falling to the bottom of the device is significantly reduced. In this case, air is also injected from the gap between the seventh rung part '70a of the air injection member 70 and the inclined plate 80, thereby preventing the pulverized coal from falling from this f';l(minute).

FIG. 5 shows a second embodiment. In the case of this embodiment, an opening area adjusting plate 91 having an opening 90 formed therein so as to correspond to the opening [1 part 7], a of the air injection passage 71 is disposed on the surface of the air injection member 70. This adjustment plate 91 has a long hole 92
It is attached to the air injection member 70 by bolts 93 via the adjusting plate 91, and by adjusting the position of the adjustment plate 91, the opening area of the air injection passage 71 can be adjusted, and the air injection speed can be adjusted. It is something. This makes it possible to set the optimum injection speed for supplying the pulverized coal to the classifier without changing the airflow.

FIG. 6 shows a third embodiment. In this embodiment, the outer peripheral edge portion of the air injection member 70 is inclined diagonally downward, and an air injection passage 94 is also formed in this inclined portion 70b. This air injection passage 94 has an inclined part'
Since it is formed almost perpendicularly to 70b, it is positioned obliquely at a predetermined angle θ2 with respect to the horizontal plane.

In this case, the angle θ2 is preferably about 45, for example, so that the airflow is directed toward the ball 7, and the large-diameter particles are directly re-supplied to the crushing section.

By carrying out this invention, the gas such as air supplied to the crushing device is injected without creating a vortex, and almost all of the crushed coal is transported to the classifier, and the amount of coal that falls to the bottom of the device is can be reduced to extremely small amounts.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional ball mill, Fig. 2 is a sectional view showing details of the air jet plate of the ball mill shown in Fig. 1, Fig. 3 is a partial sectional view of the crushing device according to the present invention, and Fig. 4. is the third
FIG. 5 is a cross-sectional view of the air propellant material showing the second embodiment, and FIG. 6 is a cross-sectional view of the crushing device i"1" showing the third embodiment. . 7...Crushing ball 9...Lower roller 70...Air injection member 70b...Slope part 7], 94...Air injection Passage 91... Opening volume adjustment plate Fig. 3 Fig. 5

Claims (1)

[Scope of Claims] 1. In an apparatus in which a material to be crushed is crushed by balls that roll due to the rotation of a lower roller, and the crushed particles are airflow-transported to the classifier side by gas supplied into the device, an air injection member is provided. A crushing device characterized in that it is attached to a side edge of a lower roller, and an air injection passage is formed for the air injection member. 2. The crushing device according to claim 1, wherein the air injection passage is formed obliquely at a certain angle with respect to a horizontal plane. 3. Place an opening on the surface of the air injection material at a position corresponding to the opening of the air injection passage, and install an opening area adjusting plate whose position can be changed to adjust the opening area of the air injection passage. The crushing device according to claim 1, characterized in that the crushing device is configured to obtain the desired results. 4. Claim 1, characterized in that the side edge of the air injection member is formed obliquely so as to be inclined toward the grinding ball side to form an inclined part, and an air injection passage is also provided for this inclined part. Grinding equipment as described in section.