JP2016087544A - Vertical roller mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical roller mill capable of more reliably preventing the penetration of rough particles into a classifier without providing a complicated mechanism such as a reject chute.SOLUTION: A vertical roller mill comprises: a cylindrical housing; a grind part which is provided in a bottom section within the housing and which grinds a matter to be ground; a classifier which is provided above the grind part within the housing; and a transportation mechanism which forms an upward flow for transporting the ground matter which has been ground by the grind part to the classifier, and comprises an annular guide part which is provided to have an annular shape along an inner wall surface of the housing between the grind part and the classifier, and which has an upward flow guide flow passage guiding the upward flow and a fallen ground matter guide passage guiding the ground matter falling from the classifier side while avoiding the upward flow guide flow passage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vertical roller mill.

  For example, as shown in Patent Documents 1 to 3, a vertical roller mill has been used as an apparatus for pulverizing and classifying an object to be crushed such as lump coal or cement into a desired particle diameter. This vertical roller mill pulverizes the object to be crushed in the pulverization unit, puts the pulverized product on an air stream, raises the pulverized material, and classifies the raised pulverized material with a classifier provided above the pulverization unit.

  By the way, in such a vertical roller mill, the classification performance for classifying the pulverized material by the particle diameter is important. Since the classification performance is judged to be lower as the proportion of coarse particles mixed into fine particles increases, it is required to prevent the coarse particles from being mixed into fine particles. For this reason, the vertical roller mill is devised to take in only fine particles from which coarse particles have been removed by a classifier, and the coarse particles are again dropped into the pulverizing section.

  For example, in Patent Document 1, a rectifying mechanism using fixed wings is installed on the outer periphery of a rotary classifier, and a baffle plate is installed between the fixed wings and the rotary wings. By lowering the value, the coarse particles are prevented from having a large inertial force, and the coarse particles are prevented from entering the classifier. Moreover, in patent document 2, the inside of a mill is divided by the funnel-shaped structure called a guide cone, and the circulation by the upward flow which blows up the outer periphery inside a mill and the flow which descends in the mill center vicinity is formed. Further, in Patent Document 3, the flow is reversed at the reversing unit, and coarse particles are returned by the reject chute.

JP 2000-51723 A JP 2009-189909 A JP 2014-54585 A

  However, in Patent Document 1, since the range where the baffle plate can be installed is narrow, a downward flow is not generated as a whole, and the flow velocity is high in the vicinity of the break of the baffle plate. For this reason, the probability that coarse particles enter the classifier remains in the region where the flow velocity is high. Moreover, since the structure which reverses a flow and returns coarse particle | grains by a rejection chute is employ | adopted in patent document 1 similarly to patent document 3, an apparatus structure becomes complicated. Moreover, since Patent Document 3 also has a configuration in which a reject chute is provided, the configuration of the apparatus becomes complicated.

  On the other hand, Patent Document 2 has a simple device configuration provided with only a guide cone, but when the upward flow velocity is low, coarse particles that accumulate on the inner wall surface side of the housing due to classification are outside the guide cone. It is interfered with the upward flow that flows through and is blown up again. For this reason, the possibility that coarse particles enter the classifier increases as the coarse particles are repeatedly blown up by the upward flow. Further, when the upward flow velocity is high, coarse particles are also lifted up to the upper end of the guide cone, and there is a possibility of entering the classifier with a large inertial force. This is an event that is also a concern in Patent Document 1. In Patent Document 1, a configuration in which a baffle plate is installed is used to prevent this.

  The present invention has been made in view of the above-described problems, and in a vertical roller mill, without providing a complicated mechanism such as a reject chute, more reliably prevents coarse particles from entering the classifier, and The purpose is to return the coarse particles to the pulverization section more reliably.

  In order to achieve the above object, in the present invention, as a first solving means, a cylindrical housing, a pulverizing portion provided at the bottom of the housing and pulverizing an object to be crushed, and the pulverization in the housing A vertical roller mill comprising: a classifier provided above a section; and a transport mechanism that forms an upward flow in the housing for transporting the pulverized material pulverized by the pulverizer to the classifier, the pulverizer And the classifier are provided annularly along the inner wall surface of the housing, and fall from the classifier side avoiding the upflow guide channel for guiding the upflow and the upflow guide channel. A means is provided that includes an annular guide portion having a falling pulverized material guide path for guiding the pulverized material.

  As a second solution means, in the first solution means, the falling ground material guide path is provided on the upper surface side of the annular guide part, and the upward flow guide channel is provided on the lower surface side of the annular guide part. In the plan view, a means is employed in which a plurality of the upward flow guide passages and the falling pulverized material guide passages are arranged alternately and annularly.

  As a third solving means, in the first or second solving means, the falling pulverized material guide path includes a descending inclined surface that narrows and descends radially inward of the housing, and the descending inclined surface. A means is adopted in which the housing has a side wall surface that is disposed between both sides in the circumferential direction of the housing and protrudes upward.

  As a fourth solving means, in any one of the first to third solving means, the upward flow guide channel includes a rising inclined surface that squeezes and rises radially inward of the housing, and the rising inclination A means is adopted in which the surface is disposed between both sides of the housing in the circumferential direction and has a side wall surface projecting downward.

  According to the present invention, the annular guide portion that is annular along the inner wall surface is provided on the inner wall surface of the housing between the pulverization unit and the classifier. Further, the annular guide portion has an upward flow guide channel for guiding the upward flow formed by the transport mechanism, and a falling pulverized material guide path for guiding the pulverized material falling from the classifier side, A falling ground material guide path is provided to avoid the upward flow guide path. For this reason, the upward flow is guided by the upward flow guide channel, and the fall pulverized product is guided by the fall pulverized product guide path, so that the upward flow and the fall pulverized product interfere with each other in the vicinity of the inner wall surface of the housing. Can be prevented. Coarse particles that are not taken into the classifier fall from the classifier as a fall pulverized product. Therefore, according to the present invention, it is possible to prevent the falling coarse particles from interfering with the upward flow, and the coarse particles are blown up again. Can be suppressed. Therefore, according to the present invention, in the vertical roller mill, it is possible to more reliably prevent coarse particles from entering the classifier without providing a complicated mechanism such as a reject chute or a louver type fin.

It is a longitudinal cross-sectional view which shows schematic structure of the vertical roller mill which concerns on one Embodiment of this invention. (A) is a top view of the annular guide part with which the vertical roller mill which concerns on one Embodiment of this invention is provided, (b) is the front view which looked at a part of annular guide part from the radial inside of the housing. It is a perspective view which shows a part of annular guide part with which the vertical roller mill which concerns on one Embodiment of this invention is provided. (A) is AA sectional drawing of FIG.2 (b), (b) is BB sectional drawing of FIG.2 (b). (A) is a perspective view which shows a part of annular guide part with which the 1st modification of the vertical roller mill which concerns on one Embodiment of this invention is equipped, (b) is a vertical roller mill which concerns on one Embodiment of this invention. It is a perspective view which shows a part of annular guide part with which the 2nd modification is provided.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A vertical roller mill 1 according to the present embodiment pulverizes a lump coal (raw coal) as an object to be pulverized, classifies and discharges pulverized coal (pulverized material) having a desired particle diameter, and has a cylindrical housing 2. A supply unit 3 for supplying a lump (raw coal) as a material to be crushed into the housing 2, a pulverization unit 4 provided at the bottom of the housing 2, and a rotational classification provided at the top in the housing 2. A machine 5, a transport mechanism 6 that forms an upward flow for transporting the pulverized material to the rotary classifier 5, and an annular guide portion 7 provided on the inner wall surface of the housing 2.

  The housing 2 has a substantially cylindrical shape that is erected along the vertical direction, and has a lid 2a that covers the upper opening. A cylindrical supply unit 3 is inserted through the center of the lid 2a. The supply unit 3 is arranged along the vertical direction, and an upper opening thereof is arranged outside the lid body 2a, and a lower opening is arranged below the rotary classifier 5 in the housing 2. . A raw coal supply device such as a shooter (not shown) is connected to the upper opening of the supply unit 3 so that a predetermined amount of lump coal (object to be crushed) is automatically supplied into the housing 2. It has become.

  The crushing unit 4 rotates the crushing table 4 a along the circumferential direction of the housing 2, a crushing table 4 a provided at the bottom of the housing 2, a plurality of rotating rollers 4 b that roll on the crushing table 4 a, and the crushing table 4 a. And a drive device (not shown). The crushing table 4a is formed by combining a plurality of table segments (not shown) in a disk shape, and is configured such that the disk rotates at a relatively low speed on a horizontal plane. The rotating roller 4b is brought into pressure contact with the outer peripheral portion of the crushing table 4a by hydraulic pressure or a spring, and rolls on the crushing table 4a by rotation of the crushing table 4a in this state.

  Such a pulverizing unit 4 moves the lump coal (object to be crushed) supplied from the supply unit 3 to the central portion of the pulverizing table 4a to the outer peripheral side thereof by the centrifugal force of the pulverizing table 4a, and the upper surface of each table segment. And the rotating roller 4b, and are pulverized by a compressive force and a shearing force.

  The rotary classifier 5 is attached to the bottom surface side of the lid 2a. This rotating classifier 5 is a rotating rotor (not shown) provided at the center of the lid 2a, and a large number of rotating classifying blades 5a are arranged at equal intervals in the circumferential direction of the rotating rotor. By rotating the rotating rotor by means of (not shown), the rotating classification blade 5a is rotated in the same direction at a predetermined rotating speed, for example, about several tens to hundred rpm.

  Such a rotary classifier 5 pushes coarse particles larger than a predetermined particle size (hereinafter referred to as coarse coal) to the outside of the rotary classifier 5 by the centrifugal force of the airflow generated by the rotation of the rotary classifying blade 5a. This large coarse coal is dropped by gravity. Further, particles smaller than a predetermined particle size (hereinafter referred to as pulverized coal) are passed between the rotary classification blades 5a and passed therethrough. And as shown in FIG. 1, it passes the discharge pipe 5b provided in the cover body 2a, and discharges it as the product pulverized coal outside the housing 2.

  An airflow guide 10 is provided below the rotary classifier 5 below the rotary classifying blade 5a. The airflow guide unit 10 has a truncated cone shape with a small diameter on the lower side and a large diameter on the upper side, and guides an updraft described later along the outer circumferential surface to the outer circumferential side of the rotary classifier 5. .

  The transport mechanism 6 includes an intake portion 6a provided on the bottom side surface of the housing 2 and suction means (not shown) for sucking external air from the intake port 6a1 of the intake portion 6a. The air sucked into the housing 2 by the suction means is guided onto the crushing table 4a, and then the inside of the housing 2 is raised and flows into the rotary classifier 5. Under such a configuration, the transport mechanism 6 forms an upward flow X from the bottom side in the housing 2, that is, the grinding table 4a side, toward the upper side in the housing 2, that is, the rotary classifier 5 side. The pulverized material Y on the pulverizing table 4a, that is, pulverized coal and some coarse pulverized coal, is raised on the rising flow X and transported to the rotary classifier 5 side.

  The annular guide part 7 is an annular member provided on the inner wall surface of the housing 2 between the crushing part 4 and the rotary classifier 5. The annular guide portion 7 is provided along the inner wall surface of the housing 2 and is arranged coaxially with the housing 2 when viewed from above. FIG. 2A is a plan view of the annular guide portion 7. FIG. 2B is a front view of a part of the annular guide portion 7 as viewed from the radially inner side of the housing 2. FIG. 3 is a perspective view showing a part of the annular guide portion 7. FIG. 4A is a cross-sectional view taken along the line AA in FIG. Moreover, FIG.4 (b) is BB sectional drawing of FIG.2 (b). As shown in these drawings, the annular guide portion 7 has a falling pulverized material guide path 71 on the upper surface side and an upward flow guide channel 72 on the lower surface side.

  The falling pulverized material guide path 71 is a passage for guiding the pulverized material Y falling from the rotary classifier 5 side (that is, the upper side). The falling pulverized material guide path 71 is disposed with a descending inclined surface 71a constricting and descending radially inward of the housing 2, and the descending inclined surface 71a sandwiched from both sides in the circumferential direction of the housing 2 and above. And two side wall surfaces 71b protruding toward the surface. Further, the descending inclined surface 71 a has a substantially isosceles triangular shape with the tip directed inward in the radial direction of the housing 2. The pulverized material Y that has fallen on the falling pulverized material guide path 71 falls along the inclination of the descending inclined surface 71a and is collected at the tip of the descending inclined surface 71a by the side wall surface 71b. Fall towards the.

  The upflow guide channel 72 is a passage for guiding the upflow X rising from the bottom of the housing 2. The ascending flow guide channel 72 is disposed so as to squeeze and rise toward the radially inner side of the housing 2, and the ascending inclined surface 72 a is sandwiched from both sides in the circumferential direction of the housing 2 and is positioned below. And two side wall surfaces 72b protruding toward the surface. Further, the rising inclined surface 72 a has a substantially isosceles triangular shape with the tip directed toward the inside in the radial direction of the housing 2. The upward flow X that collides with the upward flow guide channel 72 rises along the inclination of the upward inclined surface 72a and is collected at the tip of the upward inclined surface 72a by the side wall surface 72b. Ascend towards.

  Note that the side wall surface 72b of the upward flow guide channel 72 is disposed on the back surface side of the descending inclined surface 71a of the falling pulverized material guide path 71, and the falling pulverization is performed on the back surface side of the upward inclined surface 72a of the upward flow guide channel 72. A side wall surface 71b of the object guide path 71 is disposed. Furthermore, the tip of the descending inclined surface 71 a of the falling pulverized material guide path 71, the end of the side wall 71 b of the falling pulverized material guide path 71 on the center side of the housing 2, and the tip of the rising inclined surface 72 a of the upward flow guide channel 72. The end of the side wall surface 72 b of the upward flow guide channel 72 on the center side of the housing 2 is disposed at the same distance from the center of the housing 2 in the radial direction of the housing 2. Thereby, the edge 73 on the center side of the housing 2 of the annular guide portion 7 has a triangular wave shape that swings up and down when viewed from the center side of the housing 2.

  In such an annular guide portion 7, the fall pulverized material guide paths 71 and the upward flow guide paths 72 are alternately and annularly arranged in a plan view. That is, the position where the pulverized material Y falls from the falling pulverized material guide path 71 and the position where the upward flow X flows out from the upward flow guide channel 72 are shifted so as to deviate in the circumferential direction of the housing 2 in plan view. A guide path 71 and an upflow guide path 72 are arranged. That is, as shown in FIG. 3, in the vertical roller mill 1 of the present embodiment, the falling pulverized material guide path 71 guides the pulverized material Y falling from the rotary classifier 5 side while avoiding the upward flow guide channel 72.

  When pulverized coal is generated in the vertical roller mill 1 of the present embodiment having such a configuration, lump coal (raw coal) is supplied from the supply unit 3 to drive the pulverization unit 4, and the transport mechanism 6, Each of the rotary classifiers 5 is driven. As a result, the lump coal is pulverized in the pulverization unit 4 to become coarse coal or pulverized coal. Coarse coal or pulverized coal formed in the pulverizing unit 4 is put on the upward flow X generated by the transport mechanism 6 and is transported from the pulverizing table 4 a of the pulverizing unit 4 to the upper side in the housing 2. At that time, the air sucked by the suction means of the transport mechanism 6 is guided and flows in the circumferential direction along the inner peripheral surface of the housing 2, thereby causing a swirl flow separately from the rising component forming the rising flow X. The swirl component to be formed is added. Accordingly, the upward flow X transported with pulverized coal or pulverized coal is caused to flow toward the inner wall surface of the housing 2 due to the centrifugal force due to the swirling component, and as a result, rises in the vicinity of the inner wall surface. Become.

  The pulverized coal contained in the upward flow X is introduced into the rotary classifier 5 and discharged as a product through the discharge pipe 5b. Moreover, the coarse pulverized coal contained in the upward flow X is pushed out to the inner wall surface side of the housing 2 by the rotary classifier 5 and dropped by its own weight to be supplied to the pulverization unit 4 again to be pulverized coal.

  According to the vertical roller mill 1 of the present embodiment as described above, the annular guide portion 7 that is annular along the inner wall surface is formed on the inner wall surface of the housing 2 between the crushing portion 4 and the rotary classifier 5. Is provided. Further, the annular guide portion 7 guides the upward flow guide path 72 formed by the transport mechanism 6 and the falling ground material guide path 71 for guiding the ground material Y falling from the rotary classifier 5 side. Furthermore, a fall ground material guide path 71 is provided so as to avoid the upward flow guide path 72 when viewed from above. For this reason, the upward flow X is guided by the upward flow guide channel 72, and the falling pulverized material Y is guided by the falling pulverized material guide channel 71, so that it falls with the upward flow X in the vicinity of the inner wall surface of the housing 2. Interference with the pulverized product Y can be prevented. Coarse coal that is coarse particles that are not taken into the rotary classifier 5 falls from the rotary classifier 5 side as the pulverized product Y that falls. According to the vertical roller mill 1 of the present embodiment, the coarse coal powder that falls and the upward flow It can suppress that X interferes and it can suppress that pulverized coal is blown up again. Therefore, it is possible to more reliably prevent the coarse coal from entering the rotary classifier 5 without providing a complicated mechanism such as a reject chute. Moreover, it becomes possible to return coarse pulverized coal smoothly to the position close to the center of the crushing table 4a, and to return to the crushing unit 4 more reliably. The classification performance can be improved.

  Further, in the vertical roller mill 1 of the present embodiment, a plurality of upward flow guide channels 72 and falling pulverized material guide channels 71 are arranged alternately and annularly in a plan view. For this reason, the upward flow guide flow path 72 and the falling ground material guide path 71 are discretely arranged in the circumferential direction of the housing 2, and the coarse coal and the upward flow X are located at any position in the circumferential direction of the housing 2. Interference can be prevented.

  Further, in the vertical roller mill 1 of the present embodiment, the fall pulverized material guide path 71 is provided with a descending inclined surface 71 a that squeezes and descends radially inward of the housing 2, and this descending inclined surface 71 a is provided on the housing 2. It has a side wall surface 71b that is disposed between both sides in the circumferential direction and protrudes upward. For this reason, the pulverized material Y falling on the descending inclined surface 71a can be collected at the tip of the descending inclined surface 71a, and the range in which the pulverized material Y falls from the falling pulverized material guide path 71 can be narrowed. For this reason, it can prevent more reliably that the fallen crushed material Y interferes with the upward flow X.

  Further, in the vertical roller mill 1 according to the present embodiment, the upward flow guide channel 72 includes an upward inclined surface 72 a that squeezes and rises inward in the radial direction of the housing 2, and the upward inclined surface 72 a is provided on the housing 2. And a side wall surface 72b that protrudes downward from both sides of the circumferential direction. For this reason, the upward flow X colliding with the upward inclined surface 72a can be collected at the tip of the upward inclined surface 72a, and the range where the upward flow X flows out of the upward inclined surface 72a can be narrowed. For this reason, it can prevent more reliably that the upward flow X interferes with the pulverized material Y which falls.

In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) Although the descending inclined surface 71a and the rising inclined surface 72a have an isosceles triangular shape with pointed tips in the above embodiment, the present invention is not limited to this. For example, as shown in FIG. 5A, the descending inclined surface 71 a and the ascending inclined surface 72 a may be trapezoidal shapes that narrow toward the radially inner side of the housing 2. In such a case, the range in which the fallen crushed material Y falls from the fallen crushed material guide path 71 and the range in which the upflow X flows out from the upflow guide channel 72 can be expanded, and the descending inclined surface 71a. And it can prevent crushing thing Y etc. adhering and clogging in the tip vicinity of rising slope 72a.

(2) In the above embodiment, the falling pulverized material guide path 71 is formed by the descending inclined surface 71a and the side wall surface 71b which are bent and connected, and the rising inclination where the upward flow guide channel 72 is bent and connected. Although formed by the surface 72a and the side wall surface 72b, the present invention is not limited to this. For example, as shown in FIG. 5B, it is also possible to form the falling ground material guide path 71 and the upward flow guide path 72 by curved surfaces having no bent portions. In such a case, since the bent portion does not exist, it is possible to prevent the crushed material Y and the like from adhering to the falling crushed material guide path 71 and the upward flow guide channel 72.

(3) In the above embodiment, the descending inclined surface 71a and the ascending inclined surface 72a have an isosceles triangular shape with sharp tips, but these are, for example, the radially inner tip of the housing 2 in the turning direction of the upward flow X It is also possible to have a triangular shape oriented in the direction following the above. As a result, the direction in which the fallen crushed material Y falls from the fallen crushed material guide path 71 and the direction in which the upflow X flows out from the upflow guide channel 72 follow the swirl direction of the upflow X. Decreasing the swirl component of X can be suppressed, and the flow field inside the housing 2 can be stabilized.

(4) In the above-described embodiment, the example in which the lump coal is used as the pulverized material has been described, but the present invention is not limited to this. The present invention can also be applied to a vertical roller mill that is to be crushed, such as cement.

  DESCRIPTION OF SYMBOLS 1 ... Vertical roller mill, 2 ... Housing, 2a ... Cover body, 3 ... Supply part, 4 ... Grinding part, 4a ... Grinding table, 4b ... Rotating roller, 5 ... Rotary classifier, 5a ... Rotary classification blade, 5b ... Discharge Pipe 6, transport mechanism, 6 a, intake portion, 6 a 1, intake port, 7, annular guide portion, 10, air flow guide portion, 71, falling ground material guide path, 71 a, descending inclined surface, 71 b, side wall surface, 72, Ascending flow guide channel, 72a ... Ascending inclined surface, 72b ... Side wall surface, 73 ... Edge, X ... Ascending flow, Y ... Ground

Claims (4)

A cylindrical housing, a pulverizing unit provided at the bottom of the housing and pulverizing the object to be crushed, a classifier provided above the pulverizing unit in the housing, and a pulverized material pulverized by the pulverizing unit A vertical roller mill comprising a transport mechanism for forming an upward flow in the housing for transporting the classifier to the classifier,
Between the pulverizing section and the classifier, an annular flow path is provided along the inner wall surface of the housing, and the classifier avoids the upward flow guide path and guides the upward flow guide path. A vertical roller mill comprising an annular guide portion having a falling ground material guide path for guiding the ground material falling from the side. The falling ground material guide path is provided on the upper surface side of the annular guide part, and the upward flow guide channel is provided on the lower surface side of the annular guide part,
2. The vertical roller mill according to claim 1, wherein when viewed in a plan view, a plurality of the upward flow guide passages and the falling pulverized material guide passages are arranged alternately and annularly.   The falling pulverized material guide path is disposed so as to squeeze and descend toward the radially inner side of the housing, and the downward inclined surface is sandwiched from both sides in the circumferential direction of the housing and is directed upward. The vertical roller mill according to claim 1, further comprising a protruding side wall surface. The ascending flow guide channel is disposed so as to narrow and rise toward the radially inner side of the housing, and the ascending inclined surface is sandwiched from both sides in the circumferential direction of the housing and is directed downward. The vertical roller mill according to claim 1, further comprising a protruding side wall surface.

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