JP2002059017A - Vertical roller mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical roller mill equipped with an air stream blow-in system reduced in the pressure loss caused by the collision of air streams and capable of being adapted even to a vertical roller mill having such a system that a roller support mechanism for supporting a grinding roller is provided so as to pierce a mill casing. SOLUTION: An annular upwardly turned outside blow-up nozzle 6a is provided to the periphery of an annular upwardly turned blow-up nozzle 5a provided to the periphery of a grinding table 2 and a revolving stream blow-in port 11a for blowing in revolving air streams along the inner periphery of the mill casing 1 is provided at a position above the grinding roller 3 of the casing 1. The air pressurized by a mill fan 8 is supplied through the revolving stream blow-in port 11a, the outside blow-up nozzle 6a and an air supply duct 7, and the air pressurized by a pressure fan 10 is supplied to the blow-up nozzle 5a through an air dividing duct 9 branched from the downstream side of the air dividing position to the revolving stream blow-in port 11a of the air supply duct 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for crushing a raw material between a rotating table and a roller, transporting the generated powder in an air flow, and transferring the powder product from an upper discharge duct. For more details on the improvement of the vertical roller mill to be taken out,
The pressure loss due to the collision of the airflow is small, and the roller support mechanism that supports the crushing roller has an airflow blowing method that can be applied to a vertical roller mill of a type provided through the mill casing. It belongs to the technical field of vertical roller mills.

[0002]

2. Description of the Related Art As is well known, a vertical roller mill has excellent grinding efficiency of raw material per power, a small installation area,
It is easy to increase the size,
It is a system in which the powder is conveyed by a 00% air stream and taken out of the mill, and is often used because it has an advantage that the powder can be dried in the mill by supplying hot air.
As such a vertical roller mill, for example, Japanese Patent Publication No. Sho 62
What is disclosed in -16693 is known. Hereinafter, the outline of the vertical roller mill according to this conventional example,
With reference to FIG. 5 of the overall side sectional view and FIG. 6 of the enlarged sectional view of the periphery of the crushing table, the same names and the same reference numerals described in the same publication will be used for the description.

[0003] Reference numeral 1 shown in the figure denotes a mill casing which is a main body of a pulverizing apparatus, in which a pulverizing table 3 rotated by a motor (not shown) via a speed reducer 2 is provided. A crushing groove 4 formed in the crushing table 3 is supported in the mill casing 1 so as to be movable up and down, and a frame 7 to which a downward pressing force is applied by a hydraulic cylinder 8.
The tire portions 5 of the plurality of crushing rollers 6 rotatably supported in contact with each other. An annular blow-up nozzle 9 is provided around the crushing table 3 and through a slight gap with the outer periphery of the crushing table 3. This blowing nozzle 9 is attached to the mill casing 1,
It is divided at regular intervals by a number of obliquely upward wings.

[0004] Reference numeral 10 shown in the drawing denotes an air introduction hole for supplying air to the blow-up nozzle 9, which communicates with the blow-up nozzle 9 via an air passage 11. On the upper side of the blow-up nozzle 9 of the mill casing 1, an air ring 12 protruding from the outer periphery of the mill casing 1 is provided. This air passage 12 is connected to a lift chamber 1 in the mill casing 1 through a number of air outlets 14 partitioned by a number of vanes 13 deflected in the same direction as the blowing nozzle 9.
It is in communication with 5. Reference numeral 16 denotes the air circulation path 12.
And an external air duct (not shown).

[0005] Reference numeral 18 shown in the figure is a separator (hereinafter referred to as a separator).
It is called a classifier. ), Has a number of rotors 19 on the peripheral surface,
The rotating blade 1 is rotated by a motor (not shown) on the upper part of the main body.
The centrifugal force is applied to the powder ascending in the wind-up chamber 15 by the rotation of 9 to classify the powder. An input pipe 20 for supplying raw material, which enters the lift chamber 15 obliquely from the mill casing 1.
Are open toward the upper surface of the pulverizing table 3 and further open to the top of the mill casing 1.
1 is for discharging the powder product classified by the classifier 18 to the outside together with air.

[0006]

Briefly, the vertical roller mill according to the above-mentioned conventional example blows up the powder once pulverized from a blowing nozzle on the outer periphery of a pulverizing table and blows up the powder. By dividing a part of the air flow to be supplied to the nozzle and blowing it from a number of air vents provided on the inner periphery of the mill casing, it is carried to a classifier provided at an upper position inside the mill casing. It is. As a result, the amount of air from the blow-up nozzle having a large pressure loss can be reduced, and the power required for pulverizing the raw material is reduced.

However, the powder that has reached the outer periphery of the pulverizing table is carried upward by an air flow blown up from the blow-up nozzle and an air flow blown from the blowing port 14, and is discharged out of the system as a product. Therefore, in order to maintain this effect, an airflow having a certain upward direction and flow velocity is required. However, in the vertical roller mill according to the above-described conventional example, the directionality of the airflow blown up from the blowup nozzle is hindered by the airflow blown from the blower port. Therefore, the effect of reducing the power required for grinding is not always sufficient, and in addition, the powder cannot be efficiently transported upward, and the amount of powder retained inside the mill increases, resulting in a decrease in the raw material supply. It is necessary to control the amount, and there is a fear that the production capacity of the powder product is reduced.

In the case of the above-mentioned conventional example, in order to return the coarse powder having a relatively coarse particle size to the pulverizing table, the direction of the air flow blown up from the blow-up nozzle and the direction of the air flow blown from the blowing port are changed. Since the adjustment is made within a range of approximately 90 °, the two air streams collide with each other and cause a pressure loss of the air streams, so that the power required for pulverizing the raw material is not sufficiently reduced. In addition to this, an increase in the amount of retained powder is a factor that causes abnormal vibration during pulverization, and further reduces the production capacity of powder products. In order to prevent this, it is necessary to increase the ratio of the air flow rate blown up from the blow-up nozzle, but this significantly reduces the effect of reducing the pressure loss, which contradicts the purpose of the conventional example of reducing the pressure loss. become.

Further, as described above, since the air circulation path for introducing the air flow into the air blowing port is provided on the outer peripheral portion of the mill casing, for example, a roller support mechanism for supporting the pulverizing roller passes through the mill casing. In the vertical roller mill of the type provided, it is difficult to arrange the air circulation path, and it is not possible to adopt the air flow blowing method as in the above-described conventional example. In other words, since the type of the vertical roller mill that can adopt the air flow blowing method as in the conventional example is limited,
There is also a problem that versatility is poor.

Accordingly, the object of the present invention is also applied to a vertical roller mill of a type in which a pressure loss due to the collision of an air flow is small and a roller supporting mechanism for supporting a pulverizing roller is provided through a mill casing. It is an object of the present invention to provide a vertical roller mill provided with a possible air flow blowing system.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in order to solve the above-mentioned problems, the means adopted by the vertical roller mill according to claim 1 of the present invention is as follows. A rotating crushing table is provided at the lower portion inside the mill casing, an upward blowing nozzle surrounding the crushing table is provided, and a crushing roller is pressed against the crushing table to be supplied onto the crushing table. In a vertical roller mill for pulverizing the raw material, an upward outward blowing nozzle surrounding the blowing nozzle is provided outside the blowing nozzle, and an inner periphery of the mill casing is provided above the grinding roller of the mill casing. A swirl flow inlet for blowing a swirling air flow along the air flow, and an air supply duct is connected from the mill fan to the outer blowing nozzle and the swirl flow inlet. , It is characterized in that the pressurized fan is communicated with the downstream side of the air bypass location of the air diversion duct made is interposed into the swirling flow blowing port of the air supply duct to the upflow nozzle.

[0012] The means adopted by the vertical roller mill according to the second aspect of the present invention is that a rotating crushing table is provided at the lower portion inside the mill casing, and an upward blowing nozzle surrounding the periphery of the crushing table is provided. At the same time, in a vertical roller mill that presses a pulverizing roller against the pulverizing table to pulverize the raw material supplied on the pulverizing table, an upward outward blowing nozzle surrounding the blowing nozzle is provided outside the blowing nozzle. A swirl flow blow-in port for blowing a swirling air flow along the inner periphery of the mill casing is provided above the pulverizing roller of the mill casing, and the outer blow-up nozzle and the swirl flow blow-in port are provided from a mill fan. An air supply duct is connected to the air supply duct, and an air distribution duct, in which a pressurizing fan is interposed, is connected to the air flow duct to the swirl flow inlet of the air supply duct. The above-mentioned pulverizer is connected to the blow-up nozzle from the downstream side of the apparatus, and the pulverizing is performed by sucking coarse powder having a relatively coarse particle size dropped from the air distribution duct into an outer air passage for introducing air into the outer blow-up nozzle. It is characterized in that a coarse powder return duct returning to the center of the table is branched.

The means employed by the vertical roller mill according to claim 3 of the present invention is the vertical roller mill according to any one of claims 1 and 2, wherein the blow-up nozzle and the outer blow-up nozzle are used. Alternatively, a guide vane for imparting a predetermined direction to the air flow is provided in one of the blowing nozzle and the outer blowing nozzle.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vertical roller mill according to a first embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 shown in FIG. 1 designates a mill casing which is a main body of a crushing apparatus. A crushing table 2 which is rotated by a motor via a speed reducer (not shown) is provided in a lower part of the inside of the mill casing 1. A plurality of crushing rollers 3 for crushing the above crushed object are provided. A classifier 4 is provided above the crushing roller 3, and a discharge duct 1 a for discharging a powder product is provided at the top of the mill casing 1. Although not shown, a crushing groove is formed on the upper surface of the crushing table 2 and a tire portion is formed on the outer periphery of the crushing roller 3. As is well understood from the above description, the above configuration relating to the vertical roller mill is the same as the vertical roller mill according to the above-described conventional example.

Around the crushing table 2, there is provided an annular upwardly directed blowing nozzle 5a. Outside the blow-up nozzle 5, an annular upward blow-out nozzle 6a is provided, and the outer blow-up nozzle 6a is provided above the pulverizing roller 2 of the mill casing 1 and below the classifier 4. A swirling air blowing port 11a for blowing a swirling air flow along the inner periphery of the mill casing 1 is open. An air supply duct 7 for supplying air pressurized by a mill fan 8 communicates with an outer air flow path 6 for introducing an air flow to the outer blowing nozzle 6a. A swirling air supply duct 11 having a damper therein for supplying swirling air to the air blowing port 11a is branched.

Further, an air distribution duct 9 provided with a pressurizing fan 10 is branched from a downstream side of the branch of the swirling air supply duct 11 of the air supply duct 7. The air distribution duct 9 communicates with the inner air flow path 5 that introduces air to the blowing nozzle 5a. In addition,
The one protruding downward from the outer air passage 6 is a coarse powder discharge port 12 for discharging coarse powder having a relatively coarse particle size that cannot be a powder product to the outside of the system. The coarse powder having a relatively coarse particle size, which cannot be a powder product discharged from 12, is supplied again from above the mill to the pulverizing table 2 through a charging chute (not shown) together with new raw material so that it is pulverized. It is configured.

The mode of operation of the vertical roller mill having the above configuration will be described below.
Raw materials such as coal, coke, bauxite, phosphate rock, barite, magnesite, and gypsum are supplied to the upper surface of the crushing table 2 from a charging chute (not shown). Grinding table 2
The raw material supplied to the upper surface of the crushing roller sequentially rolls into the crushing grooves on the crushing table 2 and is sandwiched between the rotating crushing table 2 and the crushing roller 3 which is pressed against the crushing table 2 and rolls. After being crushed into powder, the powder is moved in the outer peripheral direction of the crushing table 2 by centrifugal force generated by the rotation of the crushing table 2 and sequentially overflows from the upper surface of the crushing table 2.

The air sent from the mill fan 8 to the air supply duct 7 passes through the swirling air supply duct 11 and blows out from the swirling air inlet 11a into the mill casing 1 to form a swirling flow. The air is blown from the outer blowing nozzle 6a into the mill casing 1 through the passage 6 as an outer airflow. At the same time, pressurizing fan 1
The air pressurized at 0 passes through the air distribution duct 9 and the inside air flow path 5 and is blown up from the blowing nozzle 5a into the mill casing 1 as an inside air flow.

Therefore, the powder overflowing from the upper surface of the crushing table 2 is first blown upward by the inner airflow blown up from the inner blowing nozzle 5a. Among the blown powders, coarse powder having a relatively coarse particle size falls onto the pulverizing table 2 or moves in the direction of the outer blowing nozzle 6a, and falls down the vertical portion of the outer air flow path 6 to be coarse. The powder is discharged from the powder outlet 12 to the outside of the system. The discharged coarse powder having a relatively coarse particle size is again supplied to the pulverizing table 2 from above the mill and pulverized along with a new raw material through a charging chute (not shown) as described above.

On the other hand, the powder having a relatively fine particle size is carried upward by the inside and outside air flows blown up from the blow-up nozzle 5a and the outside blow-up nozzle 6a. In this way, the powder having a relatively fine particle size carried upward is supplied to the inner and outer air blown up from the blow-up nozzle 5a and the outer blow-up nozzle 6a, and to the swirling air blow-in port 1.
It is carried into the classifier 4 together with the swirling airflow blown from 1a. The powder having a relatively fine particle size carried into the classifier 4 is classified by the classifier 4, and the powder passing through the classifier 4 is discharged from the discharge duct 1a. It will be collected as a product.

According to the vertical roller mill according to the first embodiment, the raw material is pulverized and classified into powder products as described above. There is no possibility that the directionality of the inner airflow blown up from the raising nozzle 5a is hindered by the outer airflow blown up from the outer blowing nozzle 6a. Therefore, in addition to enabling a further reduction in the power required for pulverizing the raw material, the powder can be efficiently transported to the upper side without increasing the amount of powder retained in the mill. Since there is no need to control the amount, there is no danger that the production capacity of the powder product will decrease.

According to the vertical roller mill according to the first embodiment, as described above, the direction of the inner airflow blown up from the blow-up nozzle 5a is changed to the outer blow-up nozzle 6a.
Since there is no impediment due to the outer airflow blown up from the airflow, the pressure loss of the airflow due to the collision of the airflows is eliminated, so that the power required for pulverizing the raw material is further reduced and the powder Since there is no abnormal vibration at the time of pulverization caused by an increase in the accumulated amount of powder, a decrease in the production capacity of the powder product due to the abnormal vibration is effectively prevented.

Further, in the vertical roller mill according to the first embodiment, unlike the vertical roller mill according to the conventional example, no air circulation path is provided on the outer periphery of the mill casing to introduce an air flow into the air blowing port. Since the inner air flow path 5 and the outer air flow path 6 are all located inside the mill casing 1 and around the crushing table 2, the roller support mechanism that supports the crushing roller penetrates the mill casing. There is an effect that the technical idea of the present invention can be applied to a roller mill of a type that is provided.

The vertical roller mill according to the second embodiment of the present invention will be given the same reference numerals as those of the vertical roller mill according to the first embodiment with reference to FIG. In addition, the vertical roller mill according to the second embodiment is provided with an outer guide vane 6b for deflecting the direction of the outer air flow in the outer blowing nozzle 6a. It has the same configuration as the vertical roller mill according to the first embodiment.

According to the vertical roller mill according to the second embodiment, the direction of the outer airflow blown up from the outer blowing nozzle 6a is changed obliquely along the inner periphery of the mill casing 1 by the outer guide vanes 6b. By deflecting,
Than the case of the vertical roller mill according to the first embodiment,
There is an effect that it is possible to improve the powder carrying performance and the classification performance of the entire mill. By the way, in the vertical roller mill according to the second embodiment, as described above,
Although the outer guide vanes 6b for deflecting the direction of the outer airflow are provided only in the outer blow nozzles 6a, the same effect can be obtained by providing the guide vanes only in the blow nozzles 5a.

The vertical roller mill according to the third embodiment of the present invention has the same reference numerals as those of the vertical roller mill according to the first embodiment, with reference to FIG. In addition, the vertical roller mill according to the third embodiment is provided with the inner guide vanes 5b for deflecting the direction of the inner air flow in the blow-up nozzle 5a and the outer air flow nozzle 6a for the outer blow nozzle 6a. An outer guide vane 6b for deflecting the direction is provided, and all other components have the same configuration as the vertical roller mill according to the first embodiment.

According to the vertical roller mill according to the third embodiment, the direction of the inner air flow blown up from the blow-up nozzle 5a is controlled by the inner guide vane 5b and the outside air blown up from the outer blow-up nozzle 6a. Since the flow direction can be deflected obliquely along the inner periphery of the mill casing 1 by the outer guide vanes 6b, in addition to the effect of the vertical roller mill according to the second embodiment, the blow-up The effect that the classification performance of the powder in the nozzle 5a part improves is produced.

A vertical roller mill according to a fourth embodiment of the present invention is designated by the same reference numeral as the same as the vertical roller mill according to the first embodiment with reference to FIG. A description is given below. The major difference between the vertical roller mill according to the fourth embodiment and the vertical roller mill according to the first embodiment is that a coarse powder return duct 13 is provided instead of the coarse powder discharge port.

More specifically, similarly to the vertical roller mill according to the third embodiment, the blowing nozzle 5a is provided with an inner guide vane 5b for deflecting the direction of the inner air flow, and the outer blowing nozzle 6a. Is provided with an outer guide vane 6b for deflecting the direction of the outer airflow. Furthermore, coarse powder returning from the air distribution duct 9 to the outer air passage 6 for introducing air into the outer blowing nozzle 6a and having a relatively coarse particle size is sucked and returned to the center of the crushing table 2. The duct 13 is branched. As described above, in the vertical roller mill according to the fourth embodiment, the inner guide vanes 5b and the outer guide vanes 6b are provided. However, even if these are not provided, a certain function is exhibited. Obtaining can be easily assumed from the vertical roller mill according to the first embodiment.

Therefore, according to the vertical roller mill according to the fourth embodiment of the present invention, a powder classification effect equivalent to that of the vertical roller mill according to the third embodiment can be expected. In addition to this, the coarse powder having a relatively coarse particle size that has fallen in the vertical portion of the outer air flow path 6 is sucked by the coarse powder return duct 13 and is also lifted upward to be in the center of the crushing table 2. Since it is returned, as in the vertical roller mill according to the first, second, or third embodiment, an external transport device that transports a coarse powder having a relatively coarse particle size falling down the vertical portion of the outer air flow path 6 to a charging chute. There is no need to provide Therefore, there is an economic effect that it is advantageous with respect to the incidental equipment cost and can greatly contribute to reduction of the production cost of the powder product.

In the first to fourth embodiments, the case where both the blowing nozzle 5a and the outer blowing nozzle 6a are annular has been described as an example. However, there is no particular need for an annular shape. The blowing nozzles 5a are arranged at predetermined intervals around the crushing table 2, and the outer blowing nozzles 6a are arranged at predetermined intervals around the blowing nozzle 5a. The configuration is not limited to the configuration of the vertical roller mill according to Embodiments 1 to 4 described above, and design changes and the like can be freely made without departing from the technical idea of the present invention. is there.

[0033]

According to the vertical roller mill according to the first to third aspects of the present invention, unlike the vertical roller mill according to the conventional example, the direction of the inner airflow blown up from the blowing nozzle is changed to the outer blowing. It is not impeded by the outside air flow blown up from the nozzle. Accordingly, the power required for grinding the raw material can be further reduced, and in addition, the powder is efficiently transported upward and there is no need to reduce the supply amount of the raw material. There is no such fear.

Further, according to the vertical roller mill according to claims 1 to 3 of the present invention, as described above, the direction of the inner airflow blown up from the blow-up nozzle is changed to the outer air blown up from the outer blow-up nozzle. As a result, the power required for crushing the raw material is further reduced, and in addition to the crushing caused by the increase in the amount of retained powder, Since there is no abnormal vibration at the time, it is possible to effectively prevent a decrease in the production capacity of the powder product due to the abnormal vibration.

According to the vertical roller mill according to the first to third aspects of the present invention, unlike the vertical roller mill according to the conventional example, an air passage for introducing an air flow into an air blow port is provided on the outer periphery of the mill casing. Since the inner air flow path and the outer air flow path are all disposed inside the mill casing and around the grinding table, a roller support mechanism that supports the grinding roller is provided through the mill casing. There is an effect that the technical idea of the present invention can be applied to a roller mill of the type described.

Further, according to the vertical roller mill according to the second aspect of the present invention, the coarse powder having a relatively coarse particle size that has fallen in the vertical portion of the outer air flow path is sucked by the coarse powder return duct and upwardly. Since it is not necessary to provide an external transport device that transports coarse powder having a relatively coarse particle size that has been returned to the center of the grinding table and dropped down the vertical There is an economic effect that it is advantageous in terms of cost and can greatly contribute to reduction of the production cost of the powder product.

[Brief description of the drawings]

FIG. 1 is a schematic sectional configuration explanatory view of a vertical roller mill according to Embodiment 1 of the present invention.

FIG. 2 is a schematic sectional configuration explanatory view of a vertical roller mill according to Embodiment 2 of the present invention.

FIG. 3 is a schematic sectional configuration explanatory view of a vertical roller mill according to Embodiment 3 of the present invention.

FIG. 4 is a schematic sectional configuration explanatory view of a vertical roller mill according to Embodiment 3 of the present invention.

FIG. 5 is a side sectional view of the entire vertical roller mill according to a conventional example.

FIG. 6 is an enlarged sectional view of a peripheral portion of a pulverizing table of a vertical roller mill according to a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mill casing, 1a ... Discharge duct 2 ... Grinding table 3 ... Grinding roller 4 ... Classifier 5 ... Inner air flow path, 5a ... Blowing nozzle, 5b ... Inner guide vane 6 ... Outer air flow path, 6a ... Outer blowing Up nozzle, 6b Outside guide vane 7 Air supply duct 8 Mill fan 9 Air distribution duct 10 Pressurizing fan 11 Swirl air supply duct 11a Swirl air inlet 12 Coarse powder outlet 13 Coarse Powder return duct

Claims (3)

[Claims] 1. A rotating grinding table is provided at a lower portion inside a mill casing, an upward blowing nozzle surrounding the periphery of the grinding table is provided, and a grinding roller is pressed against the grinding table to form a grinding table. In a vertical roller mill for pulverizing the raw material supplied above, an upward outward blowing nozzle surrounding the blowing nozzle is provided outside the blowing nozzle, and the mill is provided above the grinding roller in the mill casing. A swirl flow inlet for blowing a swirling air flow along the inner periphery of the casing is provided, and an air supply duct is communicated from the mill fan to the outer blowing nozzle and the swirl flow inlet, and a pressurized fan is interposed. Characterized in that the air distribution duct is connected to the blow-up nozzle from the downstream side of the air distribution position to the swirl flow inlet of the air supply duct. Vertical roller mill. 2. A crushing table, which is rotatable at a lower portion inside the mill casing, is provided with an upward blowing nozzle surrounding the periphery of the crushing table, and a crushing roller is pressed against the crushing table. In a vertical roller mill for pulverizing the raw material supplied above, an upward outward blowing nozzle surrounding the blowing nozzle is provided outside the blowing nozzle, and the mill is provided above the grinding roller in the mill casing. A swirl flow inlet for blowing a swirling air flow along the inner periphery of the casing is provided, and an air supply duct is communicated from the mill fan to the outer blowing nozzle and the swirl flow inlet, and a pressurized fan is interposed. The air distribution duct is connected to the blow-up nozzle from the downstream side of the air distribution position to the swirl flow inlet of the air supply duct. From the air diverting duct, a coarse powder return duct that branches into the outer air passage that introduces air into the outer blowing nozzle and sucks coarse powder having a relatively coarse particle size and returns the coarse powder to the center of the crushing table is branched. Vertical roller mill. 3. A guide vane for imparting a predetermined direction to an air flow is provided in one of the blowing nozzle and the outer blowing nozzle, or one of the blowing nozzle and the outer blowing nozzle. The vertical roller mill according to any one of claims 1 and 2, characterized in that: