JP5782811B2 - Vertical mill - Google Patents

Description

  The present invention relates to a vertical mill that pulverizes lumps such as coal and limestone into fine powder.

  In a coal-fired boiler using coal as fuel, massive coal is pulverized by a vertical mill into pulverized coal, and the pulverized coal is supplied together with primary air to a burner that is a combustion apparatus.

  The vertical mill is supported by the housing, a rotary classifier that is housed in the upper part of the housing and rotates at a predetermined rotational speed, a grinding table that is housed in the lower part of the housing and rotates at the predetermined rotational speed, and the housing. A pressure roller unit, and the pressure roller unit is configured to press a rotatable pressure roller against the crushing table.

  A lump of coal is fed from the chute to the center of the crushing table and supplied to the crushing table. The supplied massive coal moves to the outer periphery by the rotational centrifugal force of the pulverizing table, and is pulverized by being caught between the pressure roller and the pulverizing table in the process of moving the coal to the outer periphery of the pulverizing table. The pulverized charcoal is raised by the primary air blown from the primary air outlet around the pulverization table, classified by a classifier, and then supplied to the burner together with the primary air.

  Since the pulverized coal blown up by the primary air is mixed with coarse pulverized coal with a large particle size and pulverized coal with a small particle size, the burden on the classifier is large, and it is replaced when the classifier is worn. Maintenance costs were high.

  In addition, there exist some which are shown by patent document 1 and patent document 2 as a vertical mill which adjusts the wind direction of the primary air which blows up pulverized charcoal, and improves classification performance. In Patent Document 1, a cylindrical downflow forming member suspended from an upper surface plate is disposed on the outer peripheral side of the rotating fin and at substantially the center position of the fixed fin and the rotating fin. A classifier that separates larger coarse particles into gravity and downward inertia force, and a vertical pulverizer including the same, and a vertical pulverizer including An equipped coal fired boiler apparatus is disclosed.

  Further, in Patent Document 2, a convex space projecting upward is formed on the ceiling portion of the housing, and the pulverized coal flow is deflected downward through the convex space and is suspended from the inner edge of the convex space. A classifier and a vertical mill are disclosed in which a larger coarse powder is dropped by gravity and a lower inertia force by guiding a pulverized coal flow deflected by a deflection ring.

JP-A-2005-324104 JP 2002-18360 A

  In view of such circumstances, the present invention provides a vertical mill that reduces the burden on the classifier, reduces maintenance costs, and improves classification performance.

  The present invention provides a housing that forms a classification chamber, a classifier provided at the upper part of the classification chamber, a pulverization table provided at the lower part of the classification chamber, and pressed by the pulverization table to pulverize the lump. A pressure roller, a primary air outlet for ejecting primary air from the periphery of the crushing table, a chute for supplying a lump to the crushing table, and an inverted cone-shaped reject provided around the chute This is a vertical mill that includes a chute and has a deflecting portion formed at the upper end of the reject chute and reverses the flow direction of the primary air passing through the deflecting portion at least twice even times.

  Further, in the present invention, the deflection unit includes an upper deflection plate and a lower deflection plate, and a classification flow path having a reversing portion bent in a crank shape is formed between the upper deflection plate and the lower deflection plate, The classification flow path relates to a vertical mill provided radially at an equiangular pitch, and the classification flow path relates to a vertical mill inclined according to the swirl angle of primary air, and the classification flow path The inversion part of the is related to a vertical mill bent in an arc shape.

  Further, according to the present invention, the deflecting portion includes a reject chute having an upper end cut off, and an inverted truncated cone portion that is located above the reject chute and has a diameter that increases obliquely upward from a central portion of the classification chamber. An upper deflection member, and a lower deflection member extending between the reject chute and the inverted truncated cone portion from the inner wall of the housing, the reject chute, the lower deflection member, the upper deflection member, and This is related to a vertical mill in which a classification flow path bent in the above is formed.

  According to the present invention, the housing forming the classification chamber, the classifier provided in the upper part of the classification chamber, the pulverization table provided in the lower part of the classification chamber, and pressed by the pulverization table, A pressure roller for crushing, a primary air outlet for ejecting primary air from the periphery of the crushing table, a chute for supplying a lump to the crushing table, and an inverted conical shape provided around the chute And a deflecting portion is formed at the upper end of the reject chute, and the flow direction of the primary air passing through the deflecting portion is reversed at least twice in an even number of times. In the process of reversing, the separation performance can be improved by separating the lump with a large particle size, the burden on the classifier can be reduced, and the maintenance cost can be reduced. Cormorant exhibits an excellent effect.

1 is a schematic sectional elevation view of a vertical mill according to a first embodiment of the present invention. The deflection | deviation part which concerns on 1st Example of this invention is shown, (A) is an AA arrow directional view of FIG. 1, (B) is a BB arrow directional view of FIG. 2 (A). The modification of the deflection | deviation part which concerns on 1st Example of this invention is shown, (A) is a schematic sectional drawing which shows the 1st modification of this deflection | deviation part, (B) is the 2nd of this deflection | deviation part. FIG. 10C is a schematic vertical sectional view showing a modified example of the above, and FIG. 10C is a schematic vertical sectional view showing a third modified example of the deflection unit. It is a schematic sectional elevation view of a vertical mill according to a second embodiment of the present invention. It is explanatory drawing which shows the additional example of a 2nd Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1, a vertical mill 1 according to a first embodiment of the present invention will be described.

  A cylindrical housing 3 is erected on a base 2 having a hollow structure or a leg structure, and a sealed space is formed by the housing 3. A pulverization table 5 is erected at a lower portion of the space via a reduction gear 4, and the pulverization table 5 is rotated at a constant speed or a variable speed by a pulverization table motor 6 via the reduction gear 4.

  On the upper surface of the pulverizing table 5, a plurality of table segments 8 having a concave groove 7 having an arcuate cross section are provided in a ring shape.

  Three sets of pressure roller units 9 provided radially from the rotation center of the crushing table 5 at a required number, for example, 120 ° intervals, and three sets of roller pressure devices 10 capable of pressing the pressure roller units 9. A journal cover 11 is provided at the lower part of the housing 3. The pressure roller unit 9 and the roller pressure device 10 are supported by the journal cover 11, and the pressure roller unit 9 has a pressure roller 12 and can be tilted via a horizontal support shaft 13. Yes.

  The roller pressure device 10 includes an actuator, for example, a hydraulic cylinder 14, and presses the pressure roller 12 against the concave groove 7 by the hydraulic cylinder 14.

  A primary air chamber 15 is formed below the crushing table 5, and a classification chamber 16 is provided above the crushing table 5 inside the housing 3.

  A primary air supply port 17 is attached to the lower portion of the housing 3, and the primary air supply port 17 is connected to a blower (not shown) and communicates with the primary air chamber 15. Around the pulverization table 5, primary air outlets 18 are provided on the entire circumference.

  A coal supply / discharge portion 19 is provided on the upper side of the housing 3, and a pipe-like chute 21 is provided so as to penetrate the center portion of the coal supply / discharge portion 19. The lower end is located above the center of the crushing table 5. Coal is supplied to the chute 21, and the supplied coal falls to the center of the crushing table 5.

  In the chute 21, a rotary tube 22 is rotatably provided on a rotary tube support 23 via a bearing 24. The rotary tube 22 is rotated by a classifier motor 29 via a pulley 25 and a belt 27 spanned between the pulley 26 and a speed reducer 28 provided with the pulley 26.

  A classifier 32 is constituted by the rotary tube 22, the pulley 25, the pulley 26, the belt 27, the speed reducer 28, the classifier motor 29, and the blade 31.

  The blade 31 has a strip shape and is arranged on the inverted conical curved surface in the circumferential direction at a required angular pitch. The blade 31 is inclined so as to be separated from the rotary tube 22 from the lower end toward the upper end, and is attached to the rotary tube 22 via a blade support portion 33.

  Below the classifier 32, an inverted conical reject chute 34 is disposed so as to partition the classifying chamber 16 up and down, and a deflection part 35 is formed at the upper end of the reject chute 34 over the entire circumference. Has been. The deflecting section 35 deflects and passes primary air containing pulverized charcoal.

  The reject chute 34 is supported by a reject chute support member 37 via a bracket 36 fixed to the chute 21 while the upper end of the deflecting portion 35 is fixed to the housing 3. The lower end of the reject chute 34 has a cylindrical shape, and the lower end is opened to form an opening 38 between the chute 21.

  A pulverized coal feed pipe 39 for feeding the pulverized pulverized coal is connected to the coal feed / discharge unit 19, and the pulverized coal feed pipe 39 is connected to a boiler burner (not shown). Yes.

  Next, the details of the deflection unit 35 will be described with reference to FIGS. 2A shows an elevational sectional view of the deflecting portion 35, and FIG. 2B shows a BB arrow view of FIG. 2A.

  The deflection unit 35 includes a plurality of upper deflection plates 41 and a lower deflection plate 42, and the upper deflection plate 41 and the lower deflection plate 42 are arranged in a row in the circumferential direction. ing. The upper deflecting plate 41 is formed by bending a plate material. The central portion of the cross section of the upper deflecting plate 41 is a concave groove 44, and both end portions of the concave groove 44 are further folded back to form an inverted concave shape. Are formed over the entire length of the upper deflection plate 41. Note that the height of the outer end portions of the reverse concave grooves 43 and 43 is lower than the height of the concave groove 44.

  The lower deflecting plate 42 is a plate material in which concave grooves 45 are formed on both ends of the reverse deflecting groove 46 so as to be bent over the entire length, and has the same cross-sectional shape as the upper deflecting plate 41. And has a shape rotated by 180 °.

  The outer end portion of the upper deflection plate 41 is inserted into the concave groove 45 so that the bottom surface of the concave groove 44 and the bottom surface of the concave groove 45 are substantially flush with each other. The portion is inserted into the reverse groove 43 so that the bottom surface of the reverse groove 46 and the bottom surface of the reverse groove 43 are substantially flush with each other.

  At this time, the heights of the outer end portions of the reverse groove 43 and the concave groove 45 are lower than the depths of the concave groove 45 and the reverse groove 43. Gaps are formed between the inner surface and the bottom surface of the concave groove 45, and gaps are formed between the outer end portion of the concave groove 45 and both the inner surface and the bottom surface of the reverse concave groove 43. Between the upper deflection plate 41 and the lower deflection plate 42, a classification channel 47, which is a crank-shaped channel that bends 180 ° twice, is formed over the entire length in the longitudinal direction. Is done. The bent portion of the classification channel 47 is a reversing portion 50 where the pulverized coal flow is reversed.

  Further, the upper deflection plate 41 and the lower deflection plate 42 are alternately arranged on the inverted conical curved surface in the circumferential direction to form the deflection portion 35. Thus, the classification channel 47 is formed radially in the deflection portion 35 at equal angular pitches in the circumferential direction.

  Next, the pulverization of coal in the vertical mill 1 will be described.

  In FIG. 1, the solid line indicates the flow of primary air, and the dotted line indicates the flow of coal.

  The pulverizing table 5 is rotated by the pulverizing table motor 6 via the speed reducer 4, and primary air at around 200 ° C. is introduced into the primary air chamber 15 from the primary air supply port 17. From the chute 21, massive coal is charged. The lump coal flows down from the lower end of the chute 21 to the center of the crushing table 5 and is supplied onto the crushing table 5.

  The coal on the pulverizing table 5 is moved in the outer peripheral direction by centrifugal force generated by the rotation of the pulverizing table 5, is pulverized into pulverized coal composed of pulverized coal and pulverized coal, and is further centrifuged. Move to the outer periphery by force.

  The primary air introduced into the primary air chamber 15 from the primary air supply port 17 blows up from the outlet 18 of the pulverizing table 5, and the pulverized charcoal that has climbed over the table segment 8 by centrifugal force, It rides on the primary air blown from the blow-out port 18 and ascends while turning the outer peripheral portion of the classification chamber 16 along the inner wall surface of the housing 3.

  As for the pulverized coal rising on the outer periphery of the classification chamber 16 on the primary air, a part of coarse pulverized coal having a large particle size falls on the pulverization table 5 due to its own weight while rising, and a part of the crushed coal 34 is rejected. The pulverized coarse coal that collides with the lower surface of the steel falls on the crushing table 5.

  The remaining pulverized coal and pulverized coal ride on the primary air and flow into the classification channel 47 as a pulverized coal flow. The pulverized coal flow that has flowed into the classification channel 47 collides with the bottom surface of the reverse concave groove 43, is inverted 180 ° vertically downward along the classification channel 47, and is deflected to a downward flow.

  The pulverized coal flow that has been reversed to the downward flow collides with the bottom surface of the concave groove 45, reverses 180 ° vertically upward again along the classification channel 47, and is deflected to the upward flow. At this time, gravity and downward inertia force act on the pulverized coal and pulverized coal against the pulverized coal flow that has been reversed to the upward flow, and the coarse pulverized coal having a large particle size is separated from the pulverized coal flow.

  Thereafter, the pulverized coal flow from which the coarse pulverized coal is separated passes through the classification channel 47, further rises in the classification chamber 16, and flows into the classifier 32.

  Further, the coarse coal separated from the pulverized coal flow in the process of passing through the classification channel 47 slides down along the slope of the concave groove 45, and the pulverization table from the opening 38 at the lower end of the reject chute 34. It falls to the center of 5.

  When the pulverized coal flow that has flowed into the classifier 32 crosses the blade 31 rotated by the classifier motor 29, coarse coal having a predetermined particle size or more collides with the blade 31 and is repelled. Further, the pulverized coal having a predetermined particle size or less crosses the blade 31 without being repelled by the blade 31, is sent out from the pulverized coal feed pipe 39, and is sent to a boiler burner (not shown). The

  Coarse pulverized coal blown off by the blade 31 falls on the outer peripheral portion of the classification chamber 16, slides along the inclined surfaces of the deflecting portion 35 and the reject chute 34, and passes through the opening 38 to the pulverizing table 5. Fall to the center. The fallen pulverized coal moves to the concave groove 7 by the rotational centrifugal force of the pulverizing table 5 and is pulverized again by the pressure roller 12.

  As described above, in the first embodiment, the deflection portion 35 is formed at the upper end of the reject chute 34, the crank-shaped classification channel 47 is formed in the deflection unit 35, and the classification channel 47 In the process of reversing the pulverized coal flow from the downward flow to the upward flow, the coarse pulverized coal flow having a large particle size due to gravity and the inertial force downward. It can be separated from the pulverized coal flow, and the classification performance can be improved.

  Further, since the above effect can be realized only by modifying the reject chute 34, the classification performance can be improved at low cost.

  Further, most of the coarse coal can be separated by the deflecting unit 35, and the amount of coarse coal flowing into the classifier 32 becomes small. Therefore, the coarse coal having a large particle size is classified by the classifier 32. This eliminates the necessity for reducing the burden on the classifier 32 and reducing the wear of the blade 31, thereby reducing the maintenance cost.

  FIGS. 3A, 3B, and 3C respectively show a first modification, a second modification, and a third modification of the deflecting unit 35 in the first embodiment.

  The primary air blown from the blowout port 18 (see FIG. 1) swirls in the classification chamber 16 (see FIG. 1) due to the inclination of the blowout port 18 and the rotation of the crushing table 5 (see FIG. 1). The pulverized coal flow made of pulverized coal and coarse pulverized coal blown up by primary air is also raised in the classification chamber 16 while swirling.

  In the first modification shown in FIG. 3A, both ends of the upper deflection plate 41 are matched with the swirl angle of the primary air, that is, the swirl angle θ of the pulverized coal flow, that is, the angle with respect to the horizontal tangent of the swirl flow. The concave grooves 43, 43 of the portion and the concave grooves 45, 45 of both ends of the lower deflection plate 42 are formed so as to be inclined by θ in the circumferential direction with respect to the first embodiment. .

  Accordingly, since the classification channel 47 is formed to be inclined in the circumferential direction in accordance with the turning angle of the pulverized coal flow, the pressure loss when the pulverized coal flow flows into the classification channel 47 can be reduced, Furthermore, when reversing the pulverized coal flow from the downward flow to the upward flow, not only gravity and inertial force downward, but also the centrifugal force in the radial direction can be applied by the inclination, which can further improve the classification performance. it can.

  Further, in the second modification shown in FIG. 3B, the reverse concave grooves 43 and 43 formed at both ends of the upper deflection plate 41 are formed in an arc shape instead of the reverse concave shape, and the lower side The concave grooves 45, 45 formed at both ends of the deflection plate 42 are not arcuate but arcuate.

  The reverse groove 43 and the concave groove 45, that is, the reversing part 50 of the classification flow path 47 is formed into an arcuate groove, whereby the S-shaped classification flow path 47 is formed. The pulverized coal flow that has flowed into the classification channel 47 is guided to the reverse concave groove 43 and smoothly reversed to the downward flow, and the downward flow is guided to the concave groove 45 and smoothly reversed to the upward flow. The

  Accordingly, when the pulverized coal flow that has flowed into the classification channel 47 is deflected, the pulverized coal flow does not stay in the classification channel 47, and pressure loss when the pulverized coal flow flows into the classification channel 47 is reduced. Can be made.

  Further, in the third modification shown in FIG. 3C, the deflecting portion 35 is configured by disposing the deflecting plates 48 at equal angular pitches in the circumferential direction.

  The deflection plate 48 is a plate material bent in a crank shape, and one end portion of the deflection plate 48 is bent to form a reverse concave groove 49 over the entire length, and the deflection plate 48. The other end of each is bent so that a concave groove 51 having a concave shape is formed over the entire length. The height of the outer end portion of the reverse groove 49 is lower than the bottom surface of the groove 51, and the height of the outer end portion of the groove 51 is lower than the bottom surface of the reverse groove 49. Yes.

  An outer end portion of the reverse groove 49 is inserted into the groove 51 so that the bottom surface of the reverse groove 49 and the bottom surface of the groove 51 are substantially flush with each other. By inserting the outer end portion of the groove 51, a crank-shaped classification channel 52 is formed between the deflection plates 48 and 48.

  In the third modified example, the distance between the classification flow paths 52 and 52 can be reduced by arranging the crank-shaped deflecting plates 48 at an equiangular pitch. By reducing the distance between the classification flow paths 52, 52, the number of the classification flow paths 52 can be increased, and the flow area of the pulverized coal flow can be increased. The pressure loss when the pulverized coal flow passes can be reduced.

  In the second modification shown in FIG. 3 (B), the reverse groove 43 and the groove 45 are made of pulverized coal flow as in the first modification shown in FIG. 3 (A). You may incline according to a turning angle. Further, in the third modified example shown in FIG. 3C, the reverse concave groove 49 and the concave groove 51 are crushed by the pulverized coal flow as in the first modified example shown in FIG. It may be inclined in accordance with the turning angle, and similarly to the second modified example shown in FIG. 3B, the reverse groove 49 and the concave groove 51, that is, the reversing portion 50 of the classification channel 52. May be arcuate. Furthermore, both the first modification and the second modification are applied to the third modification, and the reverse groove 49 and the groove 51 are tilted in accordance with the swirling angle of the pulverized coal flow and the inversion is performed. The part 50 may be arcuate.

  Next, a second embodiment of the present invention will be described with reference to FIG. 4 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  Similarly to the first embodiment, the second embodiment also has a deflection portion 53 formed at the upper end of the reject chute 34.

  The upper end of the reject chute 34 is cut out over the entire circumference, and an inlet 54 for a pulverized coal flow is formed between the upper end of the reject chute 34 and the inner wall of the housing 3. The reject chute 34 is supported on the inner wall of the housing 3 by a plurality of reject chute support members 55 arranged radially.

  An upper deflection member 57 is supported on the bracket 36 concentrically with the rejection chute 34 by a plurality of rod-like upper deflection member support members 56 above the rejection chute 34. The upper deflecting member 57 has an inverted truncated cone part 58 that has a diameter that is inclined obliquely upward from the center of the classifying chamber 16 and has the same inclination as the slope of the reject chute 34, and the inverted truncated cone part 58. It is comprised by the cylindrical part 59 extended below from a lower end. The lower end of the cylindrical portion 59 is fixed to the inner peripheral surface of the reject chute 34, and a plurality of coarse coal flow lowering ports 61 are formed at predetermined intervals in the fixed portion.

  In addition, an inverted frustoconical lower deflection member 62 is fixed to the inner wall of the housing 3 so that the lower deflection member 62 divides the space between the reject chute 34 and the upper deflection member 57 vertically. It extends to. The lower deflection member 62 has an inclination equivalent to that of the reject chute 34 and the inverted truncated cone portion 58, and the reject chute 34, the upper deflection member 57, and the lower deflection member 62 A classification flow path 63 that is bent twice is formed. The reject chute 34, the upper deflection member 57, and the lower deflection member 62 constitute the deflection unit 53.

  When the pulverization process is started, lump coal is introduced from the chute 21 and pulverized by the pressure roller 12 (see FIG. 1), and then the pulverized coal flow along the inner wall surface of the housing 3 in the classification chamber 16. Ascend while turning.

  The pulverized coal flow rising up the outer periphery of the classification chamber 16 is separated from coarse pulverized coal having a large particle diameter by its own weight or by collision with the lower surface of the reject chute 34, and the pulverized coal flow from which the pulverized coal is separated is It flows into the classification channel 63 from the inlet 54.

  The pulverized coal flow that has flowed into the classification channel 63 collides with the outer peripheral surface of the lower deflection member 62, and then flows downward toward the center along the inclination of the lower deflection member 62. Is deflected.

  The pulverized coal flow deflected to the downward flow then collides with the outer peripheral surface of the cylindrical portion 59, and is reversed into the upward flow obliquely upward toward the outer periphery along the inclination of the inverted truncated cone portion 58. The At this time, gravity and downward inertia force act on the pulverized coal and pulverized coal against the pulverized coal flow that has been reversed into the upward flow, and the coarse pulverized coal having a large particle size is separated from the pulverized coal flow. The pulverized coal flow from which the coarse pulverized coal has been separated passes through the classification flow path 63, then further rises in the classification chamber 16 and flows into the classifier 32.

  At this time, the coarse coal flow lower port 61 has a small hole diameter, and the flow resistance becomes larger than the flow path between the inverted truncated cone part 58 and the lower deflection member 62. The flow is reversed to the upward flow along the slope of the inverted truncated cone portion 58 without passing through the coarse coal flow lower port 61.

  Note that the coarse coal separated from the pulverized coal flow slides down along the slope of the reject chute 34, and the crushed coarse coal is discharged from the coarse coal flow outlet 61, and the discharged coarse coal is discharged from the opening 38. It falls on the crushing table 5 (see FIG. 1) and the crushing process is performed again.

  When the pulverized coal flow flowing into the classifier 32 crosses the blade 31, coarse coal having a predetermined particle diameter or more collides with the blade 31 and is repelled. Coarse pulverized coal repelled by the blade 31 slides down along the inclination of the inner peripheral surface of the inverted truncated cone part 58 and falls onto the crushing table 5 through the reject chute 34 and through the opening 38.

  The inverted truncated cone part 58 separates the upward flow that has passed through the deflection unit 53 and the downward flow of the pulverized coal separated by the classifier 32, so that the downward flow of coarse pulverized coal and the deflection unit 53 pass through. Interference with the upward flow is avoided, classification performance is improved, and pressure loss can be reduced.

  As described above, also in the case of the second embodiment, the reject chute 34 whose upper end is cut off, the upper deflecting member 57 having the inverted truncated cone part 58 and the cylindrical part 59, the reject chute 34 and the inverted chute. Since the classification flow channel 63 for reversing the pulverized coal flow twice is formed by the lower deflection member 62 extending between the truncated cone portion 58, the pulverized coal flow is changed from the downward flow to the upward flow. In the reversal process, coarse coal with a large particle size can be separated from the pulverized coal flow by gravity and downward inertia force, and the classification performance in the vertical mill 1 can be improved.

  Furthermore, most of the pulverized coal can be separated by the deflection unit 53, and the amount of the pulverized coal flowing into the classifier 32 is reduced, so that the burden on the classifier 32 can be reduced and the blade 31 is worn. And the maintenance cost of the classifier 32 can be reduced.

  A plurality of the pulverized coal flow lower ports 61 are formed at a predetermined interval in the fixing portion between the reject chute 34 and the cylindrical portion 59. For example, FIG. As shown in FIG. 3, a substantially triangular pyramid-shaped guide member 64 that abuts on the outer peripheral surface of the cylindrical portion 59 and the inner peripheral surface of the reject chute 34 may be provided. By providing the guide member 64 between the pulverized coal flow lower ports 61, 61, the pulverized coal flowed between the pulverized coal flow lower ports 61, 61 can be guided to the pulverized coal flow lower port 61 by the guide member 64, The discharge efficiency of the coarse coal from the classification channel 63 can be improved.

  Further, the lower end of the cylindrical portion 59 may be cut off, and a gap may be formed between the cylindrical portion 59 and the reject chute 34.

  Furthermore, in the first embodiment and the second embodiment of the present invention, the pulverized coal flow is reversed twice by the classification channel formed at the upper end of the reject chute 34. Needless to say, the number of times of reversing the flow may be four or more as long as it is an even number.

  In the present invention, the pulverization of coal has been described, but it is needless to say that the vertical mill of the present invention can also be applied to the pulverization of other massive materials such as limestone.

DESCRIPTION OF SYMBOLS 1 Vertical mill 3 Housing 5 Grinding table 12 Pressure roller 18 Outlet 21 Chute 32 Classifier 34 Reject chute 35 Deflection part 41 Upper deflection plate 42 Lower deflection plate 47 Classification flow path 48 Deflection plate 50 Inversion part 52 Classification flow path 53 Deflection part 57 Upper deflection member 61 Coarse coal flow lower port 62 Lower deflection member 63 Classification flow path 64 Guide member

Claims (4)

A housing forming a classification chamber; a classifier provided at an upper portion of the classification chamber; a pulverization table provided at a lower portion of the classification chamber; and a pressure roller pressed by the pulverization table to pulverize a lump. A primary air outlet for ejecting primary air from the periphery of the pulverization table, a chute for supplying a lump to the pulverization table, and an inverted structure provided with a deflection portion at the upper end of the chute. A classifying flow comprising a conical reject chute, the deflecting portion comprising an upper deflecting plate and a lower deflecting plate, and having a reversing portion bent in a crank shape between the upper deflecting plate and the lower deflecting plate. A vertical mill in which a path is formed, the classification flow paths are provided radially at an equiangular pitch, and the flow direction of the primary air passing through the classification flow path is reversed at least twice even times. The vertical mill according to claim 1 , wherein the classification flow path is inclined according to the swirl angle of the primary air. The vertical mill according to claim 1 or 2 , wherein the reversing part of the classification channel is bent in an arc shape. A housing forming a classification chamber; a classifier provided at an upper portion of the classification chamber; a pulverization table provided at a lower portion of the classification chamber; and a pressure roller pressed by the pulverization table to pulverize a lump. A primary air outlet for ejecting primary air from the periphery of the pulverization table, a chute for supplying a lump to the pulverization table, and an inverted structure provided with a deflection portion at the upper end of the chute. A conical reject chute, and the deflection unit is an inverted chute that is located above the reject chute and is diameter-inclined upward from the center of the classification chamber. An upper deflection member having a truncated cone part, and a lower deflection member extending between the reject chute and the inverted truncated cone part from the inner wall of the housing, Ekutoshuto, the lower deflecting member, the classification channel that is bent at the upper deflecting member is formed, and characterized in that reversing at least twice the flow direction of the primary air passing through the該分grade channel an even number of times A vertical mill.

Images