JPS5836652A - Crushing apparatus - 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 roller mill used for pulverizing mineral resources such as iron ore, limestone, and coal, and for pulverizing intermediate products.

In general, roller mills consume less electricity than ball mills, make less noise, and provide a better working environment.

It has characteristics such as short residence time of raw materials and quick response to load fluctuations, and has been used for a long time especially for pulverizing coal in pulverized coal-fired power plants.Reflecting the recent trend toward energy conservation, roller mills have been introduced. It is being reviewed in various industries.

The biggest drawback of roller mills is that the rollers are worn out by the materials being crushed.In order to maintain the mill's throughput, rollers that are worn out beyond a certain limit must be replaced with new rollers. Replacement requires considerable skill, and the replacement work is also time-consuming.

(Compared to ball mills, where you only need to replenish the balls).

A conventional roller mill of this type will be explained based on FIG. 1. In FIG. 1, 1 is a bowl, 2 is a shaft that supports and rotates the bowl 1, and 3 is a drive motor (not shown) that rotates the bowl I. A gear for transmitting rotational power, 4 is a roller, 5 is a bearing that supports the roller, and the roller 4 is given rotation by the bowl 1 via the object to be crushed. 6 is a hydraulic cylinder that presses the roller 4 against the bowl 1, and the arm 7
The roller 4 is pressed against the bowl 1 via the roller 4. Step 8: The crushed material is classified to a predetermined degree, and the fine powder is taken out as a product.

The classifier has the function of returning the coarse powder to the bowl again, 9 is a fine powder outlet from which 0.10 of the crushed material is taken out as a product, and 11 is a coarse powder inlet to be returned to the bowl.

Further, reference numeral 11 is also a raw material inlet that is supplied from a raw material supply pipe 12.

To explain the pulverizing action of this roller mill, the pulverized raw material is supplied from the supply pipe 12 and is supplied onto the bowl 1 together with the coarse powder from the first classifier coarse powder outlet 11.

The raw material and coarse powder are crushed between the rollers 4 and the bowl 1 while moving toward the outer periphery of the bowl 1.

On the other hand, the air necessary for classifying the pulverized material is supplied to the mill from a blower (not shown) 9 through an air introduction pipe 13, and a bowl l.
The powder is supplied to the grinding chamber 16 from a jet ring 15 formed by the outer periphery of the mill and the mill cruising 14 at a wind speed of 50 to 80 m/-.

The pulverized material is blown up by a high-speed airflow 17 from the jet ring 15 and is supplied to the classifier 8 through the inlet 9. The classifier 8 uses gravity and inertia to separate fine powder and coarse powder, and the coarse powder is returned onto the bowl 1. The fine powder is taken out as a product from the fine powder outlet 10 and passed through a bag filter (
(not shown), etc. In a roller mill that performs such a grinding action.

Wear of the roller 4 and bowl 1 is unavoidable, but even relatively soft materials such as coal, for example, often wear quickly and cause performance deterioration. This is caused by the highly hard stone substance contained in the pulverized raw material.

Moreover, the substance of one stone is difficult to crush and has a relatively high specific gravity.

Compared to coal, the specific gravity of 1 coal is about 1.2, while quartz has a specific gravity of 2.7. Taking these into consideration, when classifying pulverized material with the 9 classifier 8, quartz has a higher specific gravity than coal even with the same particle size. The proportion of coarse powder mixed into coarse powder increases. Therefore, a large amount of quartz is present in the crushed material on the bowl l.

According to actual operational data, in the case of pulverizing coal containing about 1% of quartz, the quartz content in the pulverized material on bowl I is as high as 5 to 10 parts. In addition, in the case of pulverizing coal with a hard globe number of 55, the hard globe number of the crushed material on the bowl 1 is about 30 to 35 ()\-The smaller the hard globe number, the harder it is. Things.

For example, in the case of coal pulverization, it has been found that it is present in a very large amount in a certain particle size distribution, such as 20 to 30% in particles of 100/l to 300μ.

The present invention was made in view of the above-mentioned conventional drawbacks, and
A suction nozzle is connected to the suction fan and directs the deposits deposited on the bowl disposed inside the roller mill to the outside of the roller mill. According to the present invention, a cyclone is provided on the downstream side of the suction fan to introduce the deposits other than the predetermined particle size into the roller mill. By separating it with a cyclone, removing those containing a large amount of high hardness such as stone grains, and returning the other materials to the roller mill, the high hardness, which is the main cause of roller and bowl wear, is removed. Since hard substances are easily removed from the top of the bowl, accelerated wear of the rollers and bowl is suppressed, which in turn prevents deterioration of crushing capacity, and the need for replacing rollers, etc. is extremely reduced. Due to its action, loss of necessary components can be minimized to an extremely low level.

It has excellent effects, including great economic effects.

Embodiments of the present invention will be described below based on FIGS. 2 to 4.

In the figure, 18 is a bowl, 19 is a rotating shaft that supports and rotates the bowl 18, and 20 is a gear connected to a drive motor (not shown) that rotates the bowl 18.

21 is a roller, 22 is a bearing that supports the roller 21, and the roller 21 is rotated by the L pawl 18 through the object to be crushed.

A hydraulic cylinder 23 presses the roller 21 against the bowl 18, and the pressing force of the hydraulic cylinder 23 is transmitted to the roller 21 via an arm 24.

25 classifies the crushed material to a predetermined degree.

This is a classifier that takes out fine powder as a product and returns coarse powder to the bowl. 26 is an inlet for the pulverized material, 27 is an outlet for fine powder taken out as a product, and 28 is an outlet for coarse powder that is returned to the bowl 18.

The coarse powder outlet 28 is also a raw material input port supplied from the raw material supply pipe 27.

Reference numeral 30 denotes an air introduction pipe for introducing air necessary for classifying the pulverized material, and the air introduction pipe 3o is connected to a blower (not shown).

32 is a jet ring formed by the outer periphery of the bowl 18 and the mill casing 31, 33 is a grinding chamber, and the arrow 34 indicates a high-speed airflow generated in the jet ring.

And 35. is a suction nozzle provided facing above the pawl 18, the nozzle 35 is connected to a suction conduit 36 for suction air (or gas), and a plurality of suction holes 39 are provided on the opposite surface of the pawl 18. .

37 is an outer cylinder that guides the suction conduit 36.

A sealing member 38 seals a gap between the outer cylinder 37 and the suction conduit 36, and the outer cylinder 37 is located inside the raw material supply pipe 29.

A suction fan 40 is connected to the suction conduit 36, and a first cyclone 42 is connected to the downstream side of the suction fan 40 via a communication conduit 41.

A second cyclone 43 is connected to the downstream side of the first cyclone 42 via the fine powder discharge pipe 42 of the 41 cyclone 42, and the coarse powder discharge pipe 42 of the first cyclone α 42 and the The fine powder discharge pipes 43% of the two cyclones 43 are respectively connected to the inlet 26 of the pulverized material of the classifier 25 described above.

α Incidentally, the coarse powder discharge pipe 43M) of the second cyclone 43 is connected to a recovery section (not shown), and
Both are configured so that the separation particle size can be adjusted.

4. Cooling water spray nozzles are provided at several locations on the side wall of the grinding chamber 33.

According to this embodiment configured in this way, 1. During normal operation, the suction nozzle 35 is raised to position A shown by the broken line in FIG. In this state, the pulverized raw material is supplied from the raw material supply pipe 29 and is supplied together with the coarse powder from the first classifier coarse powder outlet 28 onto the bowl 18.

The raw material and coarse powder are crushed between the rollers 21 and the bowl 18 while moving toward the outer periphery of the bowl 18. On the other hand, the air necessary for classifying the pulverized material is supplied to the mill through an air introduction pipe 30 from a blower (not shown), and is passed through a jet ring 32 formed by the outer periphery of the bowl 18 and the mill casing 31 at a distance of 50 to 80 m/-. It is supplied to the grinding chamber 33 at wind speed.

The pulverized material is blown up by a high-speed airflow 34 from the jet 32 and is supplied to the classifier 25 from the pulverized material 26. The classifier 25 uses gravity and inertia to separate fine powder and coarse powder, and the coarse powder is returned onto the bowl 18. The fine powder is taken out as a product from the outlet 27,
O is collected by a bag filter (not shown), etc. When a predetermined operating time has elapsed and highly hard impurities such as quartz are accumulated on the bowl 18, which is the main cause of wear of the rollers and the bowl. , the supply of raw materials is stopped, and the suction nozzle 3
5 is gradually lowered, and the deposits in the bowl 18 are suctioned and discharged from the suction hole 39 by the suction fan 40. At this time, by stopping the supply of raw materials, the temperature inside the mill, the mill, and the mill exhaust gas are controlled to be below a predetermined temperature.

Note that the discharge time interval is changed as appropriate depending on the content of high hardness substances such as quartz in the raw materials.

Then, the bowl 18 is sucked and discharged by the suction fan 40.
The upper deposits are transferred to the first cyclone 42 through the connecting conduit 41.
guided by. For example, in the case of coal pulverization, the cyclono 42 collects particles of 300μ or more and sends them to the coarse powder discharge pipe 42.
& is returned to the pulverized material inlet 26 of the classifier 25 inside the mill, and these particles of 300μ or more are pulverized again by the mill.

In addition, particles of 300μ or less that are not collected by the first cyclone 42 are sent to the second stage cyclone 4 via the fine powder discharge pipe 42b.
3 (separation limit particle diameter is 100 μm), and particles of 300 μm to 10 −0 μm are collected by the same cyclone 43.

On the other hand, air or gas containing particles of 100 μm or less is returned to the crushed material inlet 26 of the classifier 25 inside the mill via the fine powder discharge pipe 43b of the second cyclone 43. Incidentally, since the particles collected by the second stage cyclone 43 contain a large amount of highly hard quartz, etc., they are discharged from the coarse powder discharge pipe 43m of the cyclone 43 to a collecting section (not shown).

In this way, according to this embodiment, with simple operation in a short time,
The wear-promoting substances accumulated on the bowl 18 can be discharged to the outside of the mill without raising the temperature inside the mill or the mill exhaust gas, suppressing the wear of the rollers 21 and the bowl 18, and extending the grinding capacity of the mill. It can be maintained for a long period of time, and the work to replace the row 221 etc. is extremely reduced, making maintenance work more efficient.

Moreover, the deposits on the bowl 18 that have been suctioned and discharged by the suction fan 40 are removed by the first cyclone 42. The second cyclone 43 separates and removes only the particles containing a large amount of high-hardness substances such as stone grains, and the other particles are returned to the mill, which significantly reduces the loss of necessary components and is economical. It has various excellent effects such as excellent performance.

The embodiments of the present invention have been described below, but of course the present invention is not limited to these embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the main parts showing a conventional roller mill, Fig. 2 is an explanatory diagram of main parts showing an embodiment of the present invention, and Fig. 3 is an explanatory diagram of the main parts of a conventional roller mill.
The bowl in the figure is a plan view, and FIG. 4 is an enlarged view of the main part of the suction nozzle in FIG. 2. 18 Baul, 35: Suction nozzle. 42: 1st Cyclone, 43: 2nd Cyclone

Claims (1)

[Claims] A suction nozzle connected to a suction fan to guide the deposits deposited on a bowl disposed inside the roller mill to the outside of the roller mill is provided facing above the bowl, and also to introduce the deposits guided to the outside of the roller mill. A pulverizing device characterized in that a cyclone is provided downstream of the suction fan to return the deposits having a particle size other than a predetermined size to the inside of the roller mill.