JP3477437B2 - Airflow classifier - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas stream classifier for classifying raw materials to be classified by gas.

[0002]

2. Description of the Related Art Conventionally, in a cement manufacturing factory, cement clinker is crushed by a crusher such as a tube mill, and the crushed cement clinker is classified into coarse powder and fine powder by an airflow classifier and the like. Cement products are manufactured by collecting fine powder.

FIG. 8 is a sectional view showing a simplified structure of a conventional typical airflow classifier 1. The airflow classifier 1 is disclosed in Japanese Patent Publication No. 57-24189. The airflow classifier 1 is provided with a casing 3 having a substantially cylindrical upper part and a conical hopper at the lower part. The casing 3 has a vertical axis, and an air inlet 2 for taking in classification air is formed in a tangential direction in a cylindrical portion of the casing 3. A fine powder discharge pipe 4 and a raw material supply pipe 5 are attached to the top of the casing 3, and a rotary shaft 6 is further inserted along the vertical axis. A rotary plate 7 is fixed to the lower end of the rotary shaft 6, and a plurality of classification blades 8 are erected on the outer peripheral portion of the rotary plate 7 at intervals in the circumferential direction. The rotating plate 7 and the classification blade 8 form a cage-shaped rotor 9.

An annular dispersion plate 10 is fixed to the upper ends of the dispersion blades 8 of the rotor 9. The dispersion plate 10 is provided at a position where the raw material drops from the raw material supply pipe 5, and an annular collision plate 11 is provided outside the dispersion plate 10 in the radial direction. The rotor 9 and the dispersion plate 10 are rotationally driven together with the rotary shaft 6 around the vertical axis. The rotor 9 is provided at substantially the same height as the air inlet 2. A plurality of guide vanes 13 are provided between the rotor 9 and the air inlet 2 at intervals in the circumferential direction. The guide vanes 13 guide the air supplied from the air inlet 2 in the tangential direction and form a swirling flow.

The raw material supplied from the raw material supply pipe 5 onto the dispersion plate 10 is discharged outward in the radial direction by the rotation of the dispersion plate 10 and is changed in direction by the collision plate 11, so that the guide vanes 13 and the dispersion vanes 8 are formed. Tucked into a very narrow classification area between The raw material pushed into this classification region is simultaneously subjected to a radial outward centrifugal force due to the rotation of the rotor 9 and a radial inward drag force due to the air introduced into the rotor 9. Assuming that the particle size in which the two opposing forces are balanced is the equilibrium particle size, the particles having a particle size smaller than the equilibrium particle size, that is, the fine powder, have an inward drag force larger than the centrifugal force, and move into the rotor 9 by the air flow to It is discharged from the discharge pipe 4. On the other hand, particles having an equilibrium particle size or more, that is, coarse powder, have a centrifugal force larger than the inward drag force, fly out to the outside of the rotor 9, fall along the inside of the guide vanes 13, and fall into the hopper of the casing 3. Sent to. In the conventional airflow classifier 1, the coarse powder and the fine powder are classified in this manner.

[0006]

The airflow classifier 1 has the following problems.

(1) The airflow classifier 1 has a classifying blade 8
Since the length in the radial direction is set to be short, the centrifugal force applied to the raw material can be set to be substantially the same over the entire length in the longitudinal direction of the classification blade 8. In addition, the classification air is guided by the guide vanes 13.
Since it is introduced horizontally inward from the outer peripheral surface of the rotor 9 in a swirling flow state, the flow velocity becomes substantially the same in the vertical direction and the radial direction of the rotor 9. As a result, the equilibrium particle size is substantially the same over the entire area of the rotor 9 in the vertical direction, so that the equilibrium particle size is distributed in a narrow particle size range, and very sharp classification is possible. Therefore, when the cement clinker is classified to produce a cement product, the produced cement product is a sharp product having a very narrow particle size width. Cement products with such a grain size range have a large amount of standard soft water, which is the amount of water required to harden a certain amount of concrete, so the fluidity of concrete when adding the same amount of water, the so-called concrete Workability deteriorates. Therefore, when the airflow classifier 1 is used as a classifier for cement clinker, there is a problem in that the quality of the cement product is apt to deteriorate due to too narrow particle size width.

(2) In the airflow type classifier 1, since the fine powder discharge pipe 4 is located at the inner peripheral portion of the dispersion plate 10 as described above,
The feed position of the raw material is close to the outer circumference of the dispersion plate and has a high peripheral speed. Therefore, the sliding speed between the raw material and the dispersion plate 10 becomes very high, and the dispersion plate 10 is easily worn. Further, since the collision plate 11 collides with the raw material, abrasion of the collision plate 11 is very likely to occur. Further, since all the raw materials including the coarse particles which are larger than necessary are pushed into a very narrow classification area between the guide blade 13 and the dispersion blade 8, the raw material comes into contact with the guide blade 13 and the dispersion blade 8. The guide vanes 13 and the dispersion vanes 8 are easily worn. Therefore, it is necessary to take measures against wear such as using a material having excellent wear resistance for these members, which causes a problem of high cost.

(3) In the airflow type classifier 1, since the flow speed of the classification air is relatively high and the total amount of the processing raw material is pushed into the narrow classification region, the air resistance of the raw material is strong and the classification air The pressure loss becomes very large. Therefore, there is a problem that the power cost of the blower that supplies the classification air increases.

The object of the present invention is to solve the above-mentioned problems, to make the product grain size wider than before, and to adjust it to a desired grain size range, and further to prevent abrasion due to contact with raw materials. An object of the present invention is to provide an airflow classifier that can reduce the pressure loss of the classification gas.

[0011]

SUMMARY OF THE INVENTION The present invention is a housing having a vertical axis and having a circular cross section perpendicular to the axis, which includes a coarse powder collecting portion formed at a lower portion and a coarse powder collecting portion. A swirl space part connected to the upper part and forming a swirl gas inlet, a classification space part connected to the upper part of the swirl space part in this order from bottom to top, and near the bottom part of the classification space part. A horizontal dispersion plate rotatably provided coaxially with the axis, a raw material supply chute for supplying a raw material onto the dispersion plate, and a space provided in the classification space above the dispersion plate in the circumferential direction, and the axis line A cage-type classification blade that rotates around and has a radially outer end that has a larger radius from the bottom to the top, and a drive source that rotationally drives the dispersion plate and the classification blade around the axis. , Circumferentially spaced around the swirl space Drilled it provided, and a plurality of guide vanes for guiding the gas introduced from the swing gas inlet tangentially,
An airflow classifier comprising: a swirling gas introduction port; and an induction blower that attracts and discharges the gas together with the powder from the radial inside of the classification blade at the upper part of the classification space.

According to the present invention, the swirl gas introduced from the swirl gas inlet forms a swirl flow in the swirl space, and while swirling, the classification space part connected to the upper part of the swirl space part rises from the bottom to the top. . The raw material supplied through the raw material supply chute to the dispersion plate provided in the classification space moves radially outward by the centrifugal force generated by the rotation of the dispersion plate and is discharged into the swirling gas. The coarse powder in the raw material released into the swirling gas falls downward and is collected in the coarse powder collecting section.The fine powder is blown up by the swirling gas and further refined into a product by the classification blade provided above the dispersion plate. It is classified into powder and recovered fine powder.

In the classifying blade, an inward wind velocity difference is generated between the upper part and the lower part of the classifying blade as described later, and the gas velocity flowing inward in the upper part is larger than that in the lower part. When the flow velocity of gas inward in the radial direction increases, it becomes difficult for even powder with a large particle diameter to fly out in the radial direction.
The equilibrium particle size increases. As a result, the equilibrium particle size varies depending on the vertical position of the classifying blade, and increases from the bottom to the top of the classifying blade, so that the particle size range of the equilibrium particle size becomes wider than in the conventional case having a uniform vertical air velocity distribution. Therefore, the grain size width of the product is widened, and it is possible to prevent the quality deterioration due to the too sharp classification to narrow the grain size width.

Further, since the raw material is supplied to the center of the dispersion plate where the peripheral speed is relatively low, and then spreads and is discharged onto the dispersion plate, the sliding speed with the dispersion plate is small and the amount of wear of the dispersion plate is reduced. can do. Further, coarse particles that are larger than necessary are preliminarily classified and collected in the dispersion part, and only fine powder is formed in the classification part. Like the airflow classifier 1, the coarse particles are formed by the classification blades and the guide blades through which all the raw materials pass. Since there is no narrow classifying space, the problem of wear of classifying blades and guide vanes is completely eliminated. Furthermore, the absence of this narrow classification space greatly reduces the pressure loss of the classification airflow, thus saving the classification energy. Further, since it is not necessary to provide a collision plate, it is not necessary to take measures against its wear.

According to the present invention, since the plurality of guide vanes for guiding the gas supplied from the swirling gas introduction port in the tangential direction is provided, the swirling flow without turbulence can be reliably formed. In addition, since the guide vanes are provided in the swirling space portion that is continuous with the lower portion of the classification space, contact between the raw material and the guide vanes can be avoided, and wear of the guide vanes can be prevented. Therefore, it is possible to omit measures against wear of the guide vanes. Further, the present invention is
A housing having a vertical axis and having a circular cross section perpendicular to the axis, a coarse powder collecting section formed in the lower part, and a swirl connecting to the upper part of the coarse powder collecting section to form a swirling gas inlet A space part and a housing in which a classification space part connected to the upper part of the swirl space part is formed in this order from bottom to top,
A horizontal dispersion plate rotatably provided coaxially with the axis near the lower part of the classification space, a raw material supply chute for supplying the raw material onto the dispersion plate, and a circumferential interval above the dispersion plate in the classification space. A basket-type classification blade that is provided in an open state and that rotates around the axis, a drive source that rotationally drives the dispersion plate and the classification blade around the axis, and is provided in the swirl space at intervals in the circumferential direction, A plurality of guide vanes that guide the gas introduced from the swirl gas inlet in the tangential direction and the gas is introduced from the swirl gas inlet, and the gas is discharged together with the powder from the radially inner side of the classification blade at the upper part of the classification space. Including an induced blower for attracting and discharging, the lower end of the classification blade is fixed to the outer peripheral portion of a horizontal annular disc coaxial with the axis, and a raw material supply chute is inserted into the center hole of the annular disc. And
The airflow classifier is characterized in that the inner peripheral portion of the annular disc is fixed to the dispersion plate via a connecting member. Further, the present invention is a housing having a vertical axis and having a circular cross section perpendicular to the axis, and is connected to a coarse powder collecting portion formed at a lower portion and an upper portion of the coarse powder collecting portion, and a swirling gas inlet And a housing in which a swirling space part in which the swirling space part is formed and a classifying space part connected to the upper part of the swirling space part are formed in this order from the bottom to the top, and in the vicinity of the lower part of the classifying space part, can be rotated coaxially with the axis. A horizontal dispersion plate provided, an annular weir provided on the outer peripheral edge of the dispersion plate and protruding upward, a raw material supply chute for supplying the raw material onto the dispersion plate, and a circumference above the dispersion plate in the classification space. A basket-type classification blade that is provided at intervals in the direction and that rotates around the axis, a drive source that rotationally drives the dispersion plate and the classification blade around the axis, and introduce gas from the swirling gas introduction port to perform classification. Radial direction above the classification blade at the top of the space A air classifier, characterized in that it comprises a attractant blower to attract exhaust gas with the powder from the inside. Further, the present invention is characterized in that the annular weir has a rectangular cross-sectional shape. Further, the present invention has a sectional shape of the annular weir,
It is characterized by being a triangle. Further, the present invention is characterized in that a plurality of guide vanes for guiding the gas introduced from the swirling gas inlet in a tangential direction are provided in the swirling space portion at intervals in the circumferential direction.

According to the invention, the outer peripheral edge of the dispersion plate is
Since the annular weir is provided, the discharge angle of the raw material can be widened as compared with the case where the weir is not provided. As a result, the dispersion area of the raw material can be used more widely, so that the powder concentration in the swirling flow can be made uniform. Therefore, the classification performance can be improved.

Further, the present invention is characterized in that the radially outer ends of the classification blades are formed so as to have a larger radius from the bottom to the top.

According to the present invention, the radially outer ends of the classification blades are formed so that the radius increases from the bottom to the top. Since the peripheral speed of the rotating body increases as the radius increases, the magnitude of the centrifugal force applied to the powder by the rotation of the classification blade can be increased from the bottom to the top. When the centrifugal force is increased, even a powder having a small particle diameter tends to fly outward in the radial direction, so that the equilibrium particle diameter can be reduced. Thereby, even when the difference in gas flow velocity between the upper part and the lower part of the classification blade becomes too large, the particle size range of the equilibrium particle size can be adjusted so as not to become too wide. Further, the equilibrium particle size can be adjusted to a desired particle size range by adjusting the radial increment amount at the radially outer end of the upper part of the classification blade. Therefore, the product grain size can be adjusted to the desired grain size.

[0019]

[0020]

Further, in the present invention, the classification space portion is a hollow inverted truncated cone portion having an inner diameter which increases from bottom to top in the vicinity of the dispersion plate and a hollow inverted truncated cone portion which is continuously connected upward to form a radial direction of the classification blade. It is characterized in that it includes a right cylindrical portion which is provided at a distance to the outside and forms an annular floating space.

According to the present invention, the classified coarse powder falls along the inner surface of the hollow inverted truncated cone part and falls near the guide vanes in the swirling space part. At this time, due to the airflow introduced from the guide vanes, fine powder to be a product mixed in the falling coarse powder is carried by the airflow and carried to the classification section. This improves the classification efficiency.

Further, according to the present invention, the lower end portion of the classification blade is
It is fixed to the outer periphery of a horizontal annular disc coaxial with the axis, a raw material supply chute is inserted through the center hole of the annular disc, and the inner periphery of the annular disc is dispersed via a connecting member. It is characterized by being fixed to the plate.

According to the present invention, the lower end of the classifying blade is fixed to the outer peripheral part of the annular disc, and the inner peripheral part of the annular disc is connected to the dispersion plate via the connecting member. The annular disc and the dispersion plate are integrally rotatable around the vertical axis. Further, since the raw material supply chute is inserted through the center hole of the annular disc, the powder to be classified can be reliably supplied to the vicinity of the central portion of the dispersion plate. Further, since the dispersion plate and the annular disc are connected to each other with a space therebetween through the connection member, the raw material can be dispersed radially outward from the dispersion plate.

[0025]

1 is a sectional view showing a simplified structure of an airflow classifier 15 which is an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG. 3 is a sectional view as seen from the section line III-III in FIG. 1, and FIG. 4 is a sectional view as seen from section line IV-IV in FIG. 1. The airflow classifier 15 is provided in the crushing device as described later, classifies the raw material crushed by the crusher into fine powder and coarse powder, and further classifies the fine powder into refined powder to be a product and recovered fine powder. .

The airflow classifier 15 has a housing 16. The housing 16 is a hollow body having a vertical axis 17, and has a circular cross section perpendicular to the axis. The housing 16 includes a coarse powder collecting portion 18 formed at a lower portion,
A swirling space portion 19 continuous with the upper portion of the coarse powder collecting portion 18 and a classification space portion 20 continuous with the upper portion of the swirling space portion 19 are formed in this order from bottom to top. The coarse powder recovery unit 18 includes a first hollow inverted truncated cone portion 23 (hereinafter referred to as a hopper) and a coarse powder discharge port 24. The inner diameter of the hopper 23 increases from the bottom to the top, and the coarse powder and the recovered fine powder, which are classified as described later, are lowered along the inner surface to be recovered. The recovered coarse powder and recovered fine powder are returned to the crusher via the coarse powder discharge port 24. Hereinafter, the coarse powder and the recovered fine powder are collectively referred to as the return powder.

The swirling space portion 19 connected to the upper portion of the coarse powder collecting portion 18 is a region for introducing a classification gas, for example, classification air, to form a swirling flow, and has a spiral flow path.
In the swirl space portion 19, a pair of swirl gas introduction ports 26 for introducing classification air from the tangential direction are formed. The pair of swirl gas introduction ports 26 are present on the imaginary diameter line 21 passing through the vertical axis 17 in a plane perpendicular to the vertical axis 17, as shown in FIG. 2, and are opposed to each other. As a result, the classification air is introduced in parallel with each other and in the opposite direction, so that a swirling flow can be formed. A plurality of guide vanes 27, which guide the classification air introduced from the swirling gas introduction port 26 in the tangential direction, are provided radially inward of the swirling gas introduction port 26 at intervals in the circumferential direction.
Each guide vane 27 is angularly displaceable around each axis parallel to the vertical axis 17. As a result, a swirling flow without turbulence can be reliably formed. The classification air rises in the housing 16 while swirling.

At the upper part of the swirling space portion 19, the classification space portion 2 is provided.
0 is continuous, and the classification space portion 20 includes a second hollow inverted circular truncated cone portion 29 continuous with the upper portion of the swirling space portion 19 and a first straight cylindrical portion 30 continuous with the upper portion of the second hollow inverse circular truncated cone portion 29. .
The inner diameter of the second hollow inverted truncated cone 29 increases from the bottom to the top. Further, an annular top plate 31 is provided at an upper end portion of the first right cylindrical portion 30, and a second hole having a diameter smaller than that of the first right cylindrical portion 30 is provided at a peripheral edge portion of a central hole of the first upper cylindrical portion 30.
The right cylindrical portion 33 is provided. The second straight cylindrical portion 33 constitutes the uppermost portion of the housing 16, and the upper end portion thereof is covered with a disc-shaped top plate 34. Further, the second straight cylindrical portion 33
The gas outlet 35 is formed in the
An exhaust gas pipeline 36 is connected to 5.

A raw material supply chute 37 extending vertically is fixed to the top plate 34, and the raw material supply chute 37 hangs in the housing 16 coaxially with the vertical axis 17. The raw material supply chute 37 includes a hollow guide inverted frusto-conical portion 38 formed in the upper part, a hollow guide right circular cylinder part 39 connected to the lower part thereof, and a right cylindrical supply cylinder part 40 connected to the lower part thereof. The outer diameter of the supply tubular portion 40 is smaller than the outer diameter of the hollow guide straight cylindrical portion 39. A plurality of (two in the present embodiment) raw material supply ports 41 are formed in the top plate 34. The raw material supply port 41 is formed along the inclined surface of the hollow guide inverted truncated cone part 38. As a result, the raw material to be classified descends along the inner surface of the hollow guide inverted circular truncated cone part 38, passes through the hollow guide right circular cylinder part 39, and is squeezed by the supply cylinder part 40 to be supplied to a desired position reliably. It becomes possible to supply raw materials to.

An electric motor 43, which is a drive source, is provided near the center of the top plate 34. The electric motor 43 engages with a rotating shaft 44 extending vertically, and the rotating shaft 44 is inserted into an insertion hole 45 and a raw material supply chute 37 formed in the top plate 34 and hangs down inside the housing 16 coaxially with the vertical axis 17. ing. The lower end of the rotary shaft 44 projects below the lower end of the supply cylinder 40 of the raw material supply chute 37, and is present near the lower end of the second hollow inverted truncated cone 29 of the classification space 20.

A dispersion plate 47 is attached to the lower end of the rotary shaft 44. The dispersion plate 47 is a horizontally extending disk-shaped member, is fixed to the rotary shaft 44 coaxially with the vertical axis 17, and is rotationally driven by the electric motor 43. An annular weir 48 protruding upward is provided on the outer peripheral edge of the dispersion plate 47. As described above, the lower end portion of the rotating shaft 44 has the supply cylinder portion 40.
It projects below the lower end of the. Since the outer diameter of the supply cylinder 40 is narrowed down, the dispersion plate 47 is arranged below the lower end of the supply cylinder 40 of the raw material supply chute 37, and the raw material to be classified is in the central portion of the dispersion plate 47. It falls near. The raw material that has dropped onto the dispersion plate 47 moves radially outward due to the centrifugal force that accompanies the rotation of the dispersion plate 47, and is discharged outward from the outer peripheral edge of the dispersion plate 47 over the annular weir 48. To be done. In this embodiment, the dispersion plate 47
The gap between the outer peripheral surface and the inner peripheral surface of the second hollow inverted truncated cone portion 29 is set sufficiently wide.

FIG. 5 is a diagram showing a simplified structure near the outer peripheral edge of the dispersion plate 47 shown in FIG. As shown in FIG. 5A, an annular weir 48 provided on the outer peripheral edge of the dispersion plate 47.
In the case where the cross-section is rectangular, the raw material 49 is blocked in a slope shape by the annular weir 48, and then is discharged obliquely upward in the radial direction outward along the formed slope.

On the other hand, when the dispersion plate 47 is not provided with the annular weir 48 as shown in FIG.
9 is emitted almost horizontally. As described above, by providing the annular weir 48, the radial movement resistance of the raw material is increased when the raw material is discharged from the dispersion plate, so that the horizontal discharge angle of the raw material is increased and the raw material dispersion area is used more widely. It becomes possible. Therefore, the powder concentration in the swirling flow can be made uniform, and the classification performance can be improved. Further, even if the raw material has poor dispersibility, the dispersibility can be enhanced. Also in FIG.
As shown in (2), even if the annular weir 50 having a triangular cross section is used, the same effect as that of the annular weir 48 in FIG. 5A can be obtained. In this case, the annular weir 50 causes the raw material 4
Since 9 cannot be blocked, the loss of raw material can be reduced.

Referring again to FIGS. 1 to 4, an annular disc 53 is provided above the dispersion plate 47 in parallel with the dispersion plate 47, that is, at a horizontal interval and coaxially with the vertical axis. There is. The annular disc 53 is connected to the dispersion plate 4 via the connecting member 54.
7 is fixed to the first straight cylindrical portion 3 of the classification space portion 20.
It is placed near the bottom of 0. As shown in FIG. 3, a plurality of connecting members 54 are provided at intervals in the circumferential direction, and connect the inner peripheral portion of the annular disc 53 and the dispersion plate 47. The diameter of the dispersion plate 47 is set smaller than the diameter of the outer peripheral surface of the annular disc 53. As a result, the passage cross-sectional area of the swirling flow can be increased, so that the pressure loss of the swirling flow can be reduced. The supply cylinder 40 of the raw material supply chute 37 is inserted through the center hole of the annular disc 53, and the lower end of the supply cylinder 40 projects below the annular disc 53.

A plurality of classification blades 56 are erected on the outer peripheral portion of the annular disc 53 in the radial direction at intervals in the circumferential direction. The classification blade 56 extends in the vertical direction in parallel with the vertical axis 17, and extends in the radial direction as shown in FIG. In the present embodiment, the radius of the radially outer end of the classification blade 56 is set to be the same over the entire length in the vertical direction, and the radial length is set to be short. A connecting ring 57 is provided at the upper end of the classification blade 56 to connect the classification blade 56 in the circumferential direction. As a result, the distance between the dispersing blades 56 in the circumferential direction is kept constant.

The annular disc 53, the classification blade 56 and the connecting ring 57 constitute a cage-shaped classification rotor 58. The classification rotor 58 is arranged coaxially with the vertical axis 17. The distance between the outer peripheral surface of the classification rotor 58 and the inner peripheral surface of the first straight cylindrical portion 30 is set sufficiently large, and an annular floating space is formed. As described above, the classification rotor 58 is connected to the distribution plate 47 via the connection member 54, and the distribution plate 47 is fixed to the rotating shaft 44. Therefore, the classification rotor 58 and the distribution plate 47 are driven by the electric motor about the vertical axis 17. It is rotationally driven integrally by 43.

The direction of rotation of the dispersion plate 47 and the classification rotor 58 around the vertical axis 17 is preferably the same as the direction of classification air introduced from the swirling gas introduction port 26. As a result, the inside of the classifying space 20 can be raised without causing turbulence in the swirling flow, so that the raw material can be classified smoothly.

The distance h1 between the inner peripheral surface of the annular disc 53 and the outer peripheral surface of the supply cylinder 40 of the raw material supply chute 37 is such that the annular disc 53 and the supply cylinder 40 are in rotation during rotation of the annular disc 53. It is set as short as possible without touching it. As a result, it is possible to block the bypass flow passage in which the swirling flow containing the powder does not pass through the classifying blade 56 but passes through the interval h1 and flows into the space on the inner side of the classifying blade 56. Therefore, it becomes possible to prevent the occurrence of a defect in which unclassified powder is mixed in the product. Further, the space h1 may be sealed by a sealing member.

An induction blower 60, which is a blower, is provided in the exhaust gas pipe 36. The induction blower 60 is, for example, a centrifugal fan, sucks the classification air from the swirling gas introduction port 26, and injects the air containing the fine powder to be the product from the inner side in the radial direction from the classification blade 56 as described later. It is drawn into the exhaust gas line 36 via 35.

Next, the operation of the airflow classifier 15 of this embodiment will be described. When the induction blower 60 is driven, the classification air is sucked from the swirling gas inlet 26, and the swirling space portion 1
A swirl flow is formed in 9. The swirling flow of the classification air rises in the classification space portion 20 while swirling. When the electric motor 43 is driven, the dispersion plate 47 and the classification rotor 58 rotate. When the pulverized raw material to be classified is supplied from the raw material supply port 41 in this state, the supplied raw material falls on the dispersion plate 47 and moves outward in the radial direction by the centrifugal force generated by the rotation of the dispersion plate 47, Classifying space portion 20 beyond the annular weir 48
Is discharged into the second hollow inverted truncated cone 29 of the.

Of the released raw material, the coarse powder that cannot be transported due to the swirling flow falls downward and is recovered by the coarse powder recovery unit 18. The fine powder that can be transported by the swirling flow is blown up while swirling by the swirling flow, reaches the first straight cylindrical portion 30, and is a fine powder that becomes a product by the classifying blade 56 that is rotationally driven, and a particle size that is smaller than that of the fine powder. It is classified into a fine powder with a large recovery. The recovered fine powder descends along the inner surfaces of the first right circular cylinder part 30 and the second hollow inverted truncated cone part 29, and is recovered by the coarse powder recovery part 18. Therefore, the coarse powder as the return powder and the recovered fine powder are recovered in the coarse powder recovery unit 18. The refined powder used as a product is
It is sucked into the exhaust gas pipeline 36 through the gas outlet 35 together with the classification air by the suction force of the induction blower 60.
The ascending wind speed of the swirling flow of the classification air is set to a relatively low wind speed, for example, 5 m / s, because only fine powder needs to be blown up.

The classification is performed as follows. In the present embodiment, the swirling flow of classification air containing fine powder is introduced into the classification blade 56 while rising upward from below. According to the investigation by the present inventors, an inward velocity component directed inward in the radial direction of the swirling flow of the classification air and an upward velocity component directed upward vary depending on the vertical position of the classification blade 56. That is, the upward velocity component becomes smaller and the inward velocity component becomes larger from the lower part to the upper part of the classification blade 56. On the other hand, the centrifugal force applied to the raw material by the rotation of the classification blade 56 is the same as the classification blade 5 as described above.
Since the radial length of 6 is short and the radius of the radially outer end is the same over the entire length in the vertical direction, there is no difference depending on the vertical position. As a result, the upper part of the classification blade 56 cannot be balanced with the increased inward velocity component of the swirling flow unless the centrifugal force is larger than that of the lower part, so that only particles having a large particle diameter can be ejected radially outward. That is, the equilibrium particle size is larger in the upper part of the classification blade 56 than in the lower part. More precisely, the equilibrium particle size varies depending on the vertical position of the classification blade 56, and increases from the bottom of the classification blade 56 to the top thereof. Therefore, in the airflow classifier 15 of the present embodiment, the equilibrium particle size range is wider than in the conventional case where the inward velocity component of the swirling flow is uniform in the vertical direction.

As described above, in this embodiment, since the particle size range of the equilibrium particle size is wider than before, when the crushed cement clinker is classified to manufacture a cement product, the particle size width of the product is made wider than before. Can also be wider.
As a result, the standard soft water content can be reduced, so that the workability of concrete can be improved and the quality of the product can be improved. Therefore, the airflow classifier 15 of the present embodiment can be suitably used as a classifier for cement clinker.

The raw material may be supplied to a central portion of the dispersion plate 47 having a relatively low peripheral speed and then discharged into a wide classification space to be widely dispersed. As in the conventional case, the raw material has a relatively high peripheral speed. There is no need to feed the position. As a result, the sliding speed between the raw material and the dispersion plate 47 is reduced, so that wear of the dispersion plate 47 can be reduced. Therefore, it is possible to solve the problem of cost increase due to measures against wear of the dispersion plate 47.

Further, since it is not necessary to provide a collision plate as in the conventional case, the problem of cost increase due to the measures against wear can be solved. Further, since the space between the dispersion plate 47 and the housing 16 is set wide as described above, the coarse powder of the raw material discharged from the dispersion plate 47 hits the housing 16 after stalling, and the fine powder is blown by the swirling flow. Can be raised. Therefore, low cost measures for the wear of the housing 16 are sufficient. Further, since the guide vanes 27 are arranged in the swirl space portion 19 where the raw material does not directly hit,
It is not necessary to take measures against wear of the guide vanes 27. Also the classification rotor 58
Since the powder concentration in the swirling flow classified by the method is much lower than the conventional one because the coarse powder has already been removed, wear of the classifying blade 56 is also reduced, and the cost for countermeasure against this wear is also reduced. be able to.

Further, since the space between the dispersion plate 47 and the classification rotor 58 and the housing 16 is set wide, the pressure loss of the classification air can be reduced. Further, since the wind speed of the swirling flow is set to a low speed, it is possible to reduce the pressure loss as compared with the conventional case where the wind speed is a high speed. Further, as described above, the powder concentration in the classifying rotor 58 is much lower than in the conventional case, so that the pressure loss becomes small.
Therefore, the induction blower 60 can be operated with a pressure loss much smaller than the conventional one, and therefore the induction blower 6 can be operated.
The power of 0 can be reduced, and energy can be saved.

FIG. 6 is a sectional view showing a simplified structure of an airflow classifier 63 according to another embodiment of the present invention.
The airflow classifier 63 of the present embodiment is similar to the airflow classifier 15 shown in FIGS. 1 to 4, and corresponding parts are designated by the same reference numerals. It should be noted that the classifying blade 64 of the present embodiment has a substantially hollow inverted truncated cone shape, and the radially outer end of the classifying blade 64 has a larger radius from the bottom to the top. It is a point formed in. In other words, in the plane including the vertical axis 17 (within the plane of FIG. 6), the vertical axis 1 increases as the classification blade 64 moves from the bottom to the top.
It is a point inclined so as to separate from 7.

The angle θ1 formed by the classification blade 64 and the vertical axis 17 in the plane is such that the radius of the radially outer end of the classification blade 64 is the same in the upper portion and the lower portion as in the airflow classifier 15. It is sometimes zero and increases as the difference between the upper and lower radii increases. Classification blade 6
When the radius of the outer end in the radial direction of 4 is increased, the peripheral speed is increased. Therefore, in the present embodiment, the magnitude of the centrifugal force applied to the powder by the rotation of the classification blade 64 is increased from the bottom to the top. be able to. When the centrifugal force is increased, even a powder having a small particle diameter tends to fly outward in the radial direction, so that the equilibrium particle diameter can be reduced.

As described above, the classifying blade 56 of the airflow classifier 15 has an equilibrium particle size distribution that varies depending on the vertical position based on the difference in the inward velocity component in the vertical direction, and goes from bottom to top. The equilibrium particle size increases.
This brings about an expansion of the particle size range of the equilibrium particle size and brings about a particle size width suitable for a cement product, but when the equipment is enlarged, the inward velocity components of the upper part and the lower part of the classification blade 56 are increased. The difference can be too large and the particle size range of the equilibrium particle size, and thus the product particle size width, can be too wide.

On the other hand, the classification blade 6 of the present embodiment
As No. 4 has the effect of reducing the equilibrium particle size as described above, the particle size range of the equilibrium particle size is optimized even when the size range of the equilibrium particle size may be excessively expanded as the equipment becomes larger. be able to. The effect of reducing the equilibrium particle size of the classification blade 64 can be adjusted by adjusting the angle θ1, and the effect of reducing the equilibrium particle size can be enhanced as the angle θ1 is increased. It is possible to adjust the particle size range. Therefore, the product particle size can be adjusted to the desired particle size, that is to say that is particularly suitable for cement products. The other configurations of the airflow classifier 63 of the present embodiment are the same as the configurations of the airflow classifier 15, and the effects of the airflow classifier 15 can be similarly exhibited.

FIG. 7 shows the particle sizes of the powder in the conventional air flow classifier 1 shown in FIG. 8, the air flow classifier 15 of the present invention shown in FIG. 1 and the air flow classifier 63 of the present invention shown in FIG. ,
It is a graph which shows the relationship with the distribution rate in the return powder of the particle size. Curve 66 in FIG. 7 represents the classification result of the conventional airflow classifier 1, curve 67 represents the classification result of the airflow classifier 63 shown in FIG. 6, and curve 68 represents the airflow classifier shown in FIG. 1
5 represents the classification result of 5. A polygonal line 69 in FIG. 7 represents the sharpest theoretical line of classification. In the polygonal line 69, the powder particle size of less than the equilibrium particle size d0 is not distributed in the return powder at all, and all the particle sizes of the powder having the equilibrium particle size d0 or more are recovered in the return powder.

From FIG. 7, it is understood that the conventional airflow classifier 63 is capable of sharp classification close to the theoretical line, that is, classification having a very narrow particle size width. Further, it is understood that the airflow classifier 15 shown in FIG. 1 is capable of classifying with a wide particle size width as shown by a curve 68. Further, it is understood that the airflow classifier 63 shown in FIG. 6 is capable of classifying particles having an intermediate particle size width as shown by the curve 67. Further, in the airflow classifier 63, by adjusting the angle θ1 as described above, it is possible to perform classification having a desired particle size width between the curves 66 and 68.

As described above, the annular weir 48 protruding upward is provided on the outer peripheral edge of the dispersion plate 47, but the invention is not limited to this. It may be integrally formed so as to protrude.
Although the swirl space portion 19 is provided with the guide vanes 27, the guide vanes 27 may be omitted. In addition, the dispersion plate 4
7 and the classification rotor 58 are connected by the connecting member 54, and the dispersion plate 47 is fixed to the rotating shaft 44 of the electric motor 43, but the invention is not limited to this, and the dispersion plate 47 and the classification rotor 58 are not connected. You may fix to the rotating shaft 44 individually. Further, the classification space 20, the classification rotor 58, and the raw material supply chute 37 may have other configurations.

[0054]

As described above, according to the present invention, the flow velocity of the gas inward in the radial direction of the classifying blade increases from the bottom to the top of the classifying blade, so that the equilibrium particle diameter is from the bottom of the classifying blade. It gets bigger as you go up. As a result, the particle size range of the equilibrium particle size becomes wider than in the conventional case having a uniform flow velocity distribution in the vertical direction, and the particle size width of the product also becomes wider. Therefore, it is possible to prevent the deterioration of quality due to the too sharp classification and the narrow particle size width. Also, since the raw material is supplied to the center of the dispersion plate where the peripheral speed is relatively slow, the slippage between the raw material and the dispersion plate is greater than in the conventional case where it is supplied to the place where the peripheral speed of the dispersion plate is relatively high. Since the speed becomes extremely small, the amount of wear can be reduced. In addition, coarse particles that are larger than necessary are classified and collected beforehand in the dispersion section, and only fine powder is collected in the classification section.There is a narrow classification space formed by the classification blades and guide blades through which all raw materials pass, as in the past. Since it does not, the pressure loss is greatly reduced, and the classification energy is saved.

Since a plurality of guide vanes for guiding the gas supplied from the swirling gas introduction port in the tangential direction are provided, a swirling flow without turbulence can be reliably formed.

According to the present invention, since the annular weir is provided at the outer peripheral edge of the dispersion plate, the discharge angle of the raw material can be widened as compared with the case where the weir is not provided. As a result, the dispersion area of the raw material can be used more widely, so that the powder concentration in the swirling flow can be made uniform. Therefore, the classification performance can be improved.

According to the present invention, the cross-sectional shape of the annular weir is rectangular or triangular, which increases the resistance of the raw material to move in the radial direction when the raw material is discharged from the dispersion plate. Becomes larger, and the dispersion area of the raw material can be used more widely. Therefore, the powder concentration in the swirling flow can be made uniform, and the classification performance can be improved. Further, even if the raw material has poor dispersibility, the dispersibility can be enhanced.

According to the present invention, since the radially outer ends of the classification blades are formed so as to have a larger radius from the bottom to the top, the magnitude of the centrifugal force due to the rotation of the classification blades is changed from the bottom to the top. You can get bigger as you go. Thereby, even when the difference in gas flow velocity between the upper part and the lower part of the classification blade becomes too large, the particle size range of the equilibrium particle size can be adjusted so as not to become too wide. Further, the equilibrium particle size can be adjusted to a desired particle size range by adjusting the radial increment amount at the radially outer end of the upper part of the classification blade. Therefore, the product grain size can be adjusted to the desired grain size. According to the present invention, the fine powder to be the product mixed in the powder that has been once classified and returned powder can be recovered again by the air flow introduced from the guide vanes, so that classification can be performed efficiently. You can

According to the present invention, since the lower end portion of the classification blade is fixed to the outer peripheral portion of the annular disc and the inner peripheral portion of the annular disc is connected to the dispersion plate via the connecting member, the classification blade, The annular disc and the dispersion plate are integrally rotatable around the vertical axis. Further, since the raw material supply chute is inserted through the central hole of the annular disc, the raw material to be classified can be surely supplied to the vicinity of the central portion of the dispersion plate. Further, since the dispersion plate and the annular disc are connected to each other with a space therebetween through the connection member, the raw material can be dispersed radially outward from the dispersion plate.

[Brief description of drawings]

FIG. 1 is a flow classifier 15 according to an embodiment of the present invention.
It is sectional drawing which simplifies and shows the structure of.

FIG. 2 is a sectional view taken along the section line II-II in FIG.

FIG. 3 is a sectional view taken along section line III-III in FIG.

FIG. 4 is a sectional view taken along the section line IV-IV in FIG.

5 is a diagram showing a simplified configuration in the vicinity of an outer peripheral edge portion of a dispersion plate 47 shown in FIG.

FIG. 6 is an airflow classifier 6 according to another embodiment of the present invention.
It is sectional drawing which simplifies and shows the structure of FIG.

FIG. 7 shows the particle sizes of the powder in the conventional airflow classifier 1 shown in FIG. 8, the airflow classifier 15 of the present invention shown in FIG. 1 and the airflow classifier 63 of the present invention shown in FIG. 5 is a graph showing the relationship with the distribution ratio in the return powder of No.

FIG. 8 is a cross-sectional view showing a simplified configuration of a conventional typical airflow classifier 1.

[Explanation of symbols]

1,15,63 Air flow classifier 16 housing 18 Coarse powder recovery unit 19 Swiveling Recovery Department 20 classification space 26 Swirling gas inlet 27 guide wings 37 Raw material supply chute 43 electric motor 44 rotation axis 47 Dispersion plate 48 ring weir 53 annular disc 54 Connection member 56 classification blades 60 induction blower 73 Crusher 74 tube mill 89 bucket elevator 90 Return line

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiko Onda 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries Ltd. Kobe factory (56) Reference JP-A-5-285412 (JP, A) JP 4-243582 (JP, A) JP 5-285455 (JP, A) JP 5-293445 (JP, A) JP 11-267592 (JP, A) Actual flat 6 -285412 (JP, U) Actual flat 6-19877 (JP, U) Actual flat 3-11470 (JP, U) Actual flat 6-77864 (JP, U) (58) Fields investigated (Int.Cl . ⁷ , DB name) B07B 1/00-15/00

Claims (9)

(57) [Claims] 1. A housing having a vertical axis and having a circular cross section perpendicular to the axis, a coarse powder collecting portion formed at a lower portion, and a swirling gas inlet connected to an upper portion of the coarse powder collecting portion. And a housing in which a swirling space part in which is formed and a classifying space part connected to an upper part of the swirling space part are formed in this order from the bottom to the top, and the swivel space part is rotatable coaxially with the axis near the lower part A horizontal dispersion plate is provided, a raw material supply chute that supplies the raw material onto the dispersion plate, and a space is provided in the classification space above the dispersion plate in the circumferential direction. A basket-type classification blade whose end has a larger radius from the bottom to the top, a drive source for rotationally driving the dispersion plate and the classification blade around the axis, and a circumferential direction in the swirl space. Turned at intervals A plurality of guide vanes that guide the gas introduced from the gas inlet port in the tangential direction, and gas is introduced from the swirling gas inlet port, and the gas is attracted together with the powder from the inner side in the radial direction of the classification blade above the classification space. An airflow classifier including an induction blower for discharging. 2. A housing having a vertical axis and having a circular cross section perpendicular to the axis, wherein a coarse powder collecting portion formed in a lower portion and an upper portion of the coarse powder collecting portion are connected to each other, and a swirling gas inlet is provided. And a housing in which a swirling space part in which is formed and a classifying space part connected to an upper part of the swirling space part are formed in this order from the bottom to the top, and the swiveling space part is rotatable coaxially with the axis near the lower part of the classifying space part. A horizontal dispersion plate provided, a raw material supply chute for supplying the raw material onto the dispersion plate, and a basket-type classification blade that is provided above the dispersion plate in the classification space at a circumferential interval and rotates around the axis. A driving source for driving the dispersion plate and the classification blade to rotate about the axis, and a plurality of tangentially guiding the gas introduced from the swirling gas inlet provided at intervals in the swirling space in the circumferential direction. Guide vanes and swirl gas inlet Gas is introduced from above, and an induction blower that attracts and discharges the gas together with the powder from the radially inner side of the classification blade at the upper part of the classification space is included, and the lower end of the classification blade is a horizontal axis coaxial with the axis. It is fixed to the outer peripheral part of the annular disc, the raw material supply chute is inserted through the central hole of the annular disc, and the inner peripheral part of the annular disc is fixed to the dispersion plate via a connecting member. An airflow classifier characterized by. 3. A housing having a vertical axis and having a circular cross section perpendicular to the axis, a coarse powder collecting portion formed in a lower portion, and a swirling gas inlet connected to an upper portion of the coarse powder collecting portion. And a housing in which a swirling space part in which is formed and a classifying space part connected to an upper part of the swirling space part are formed in this order from the bottom to the top, and the swiveling space part is rotatable coaxially with the axis near the lower part of the classifying space part. A horizontal dispersion plate provided, an annular weir provided on the outer peripheral edge of the dispersion plate and projecting upward, a raw material supply chute for supplying raw materials onto the dispersion plate, and a circumference above the dispersion plate in the classification space. Direction, a basket-type classification blade that rotates around the axis, a drive source that drives the dispersion plate and the classification blade to rotate around the axis, and a gas that is introduced from the swirling gas inlet to perform classification. Radius above the classification blade at the top of the space An airflow-type classifier, which includes an induction blower that attracts and discharges gas together with powder from inside in the direction. 4. The airflow classifier according to claim 3, wherein the annular weir has a rectangular cross-sectional shape. 5. The airflow classifier according to claim 3, wherein the annular weir has a triangular cross-sectional shape. 6. The swirl space portion is provided with a plurality of guide vanes, which are tangential to guide the gas introduced from the swirl gas introduction port, at intervals in the circumferential direction.
An airflow classifier according to any one of 5 to 5. 7. The airflow classification according to claim 2, wherein the radially outer end of the classification blade is formed to have a larger radius from the bottom to the top. Machine. 8. The classification space part includes a hollow inverted truncated cone part having an inner diameter that increases from bottom to top near the dispersion plate, and a hollow inverted frustoconical part that extends upward to extend radially outward of the classification blade. The air flow classifier according to any one of claims 1 to 7, further comprising: a right cylindrical portion which is provided at intervals and forms an annular floating space. 9. A lower end portion of the classification blade is fixed to an outer peripheral portion of a horizontal annular disc coaxial with the axis line, and a raw material supply chute is inserted into a central hole of the annular disc. The airflow classifier according to any one of claims 1 to 3, wherein an inner peripheral portion of the disc is fixed to the dispersion plate via a connecting member.