JP2617832B2 - Vertical crusher - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention separates fine materials and coarse powders in a pulverizing section of a vertical pulverizer by causing a pulverized material such as a cement raw material, a clinker, a blast furnace slag, and a chemical product to accompany an air stream. The present invention relates to a vertical mill having a rotary separator.

[0002]

2. Description of the Related Art As one type of crusher for finely pulverizing raw materials such as limestone, blast furnace slag, and cement raw materials into powder.
As shown in FIG. 7, a vertical pulverizer 1 having a rotary table and a pulverizing roller is widely used. This type of crusher includes a disk-shaped rotary table 3A that is driven by a reduction gear 2 by a motor 2A at a lower portion of a cylindrical casing 1a and that rotates at a low speed. And a plurality of crushing rollers 4 that are driven to rotate by being pressed by the like.

The crushing roller 4 is connected to a piston rod 10 of a hydraulic cylinder 9 through an arm 5 and an arm 7 which are pivotally supported by a shaft 6 on a casing 1a. The crushing roller 4 is pressed on the rotary table 3A to apply crushing pressure to the raw material. 3B is a dam ring provided on the outer peripheral edge of the rotary table 3A to adjust the thickness of the raw material layer, 14 is an annular space passage around the rotary table 3A for blowing gas, 15 is a hot air blowing passage, and 13 is a raw material pulverized by the blade 13A. Is a rotary separator for classifying the product, 16 is an outlet for taking out the product together with gas, and 17 is a raw material input chute.

In such a vertical pulverizer, the raw material supplied to the center of the rotary table 3A by the raw material charging chute 17 receives centrifugal force in the table radial direction by the rotation of the rotary table 3A and moves on the rotary table 3A. When sliding, the rotary table 3A receives a force in the rotation direction, and slides with the rotary table 3A to perform rotation somewhat slower than the rotation speed of the rotary table 3A. The above two forces, that is, the forces in the radial direction and the rotation direction are combined, and the raw material moves to the outer peripheral portion of the rotary table 3A along a spiral path on the rotary table 3A. A roller is pressed against the outer periphery of the crushing roller 4 to rotate it.
And the rotary table 3A, enter from a direction forming an angle with the roller axis direction, are caught and pulverized.

On the other hand, a gas such as air or hot air is guided to the base of the casing 1a by a duct.
This gas blows up from the annular space passage 14 between the outer peripheral surface of the rotary table 3A and the inner peripheral surface of the casing, so that the pulverized fine powder is accompanied by the gas and the casing 1
As a result, the product having a predetermined particle size is discharged from the outlet 16 together with the gas and sent to the next step.

On the other hand, the classification blade 1 of the rotary separator 13
A plurality 3a, for example, 30 to 50 concentric circles are arranged around the rotation axis 13b, and have an inclination angle so as to expand vertically or upwardly, and each have a radial radial shape in plan view. Attached to. FIG.
In the embodiment shown in FIG. 7, the classifying blades 13a use unequal angle irons.

[0007] Classification is performed by the balance between the centrifugal force acting on the particles in the contained gas and the drag force of the air flowing inward when the swirling airflow containing the fine powder pulverized in the pulverizing section flows into the classification blade 13a. Fine particles smaller than the particle size at the classification point pass through the classification blade 13a and are taken out of the system through the discharge port 16, while coarse particles are removed by the classification blade 13a and cannot pass through the classification blade 13a. It falls again into the crushing section.

[0008]

However, the flow rate of the dust-containing gas flowing into the classifying blade extending obliquely in the vertical direction is not always uniform in the vertical direction, and the average radius of the classifying blade in the upper and lower ends is different. For this reason, the classification points are different between the upper and lower parts of the classification blade, and therefore, there is a problem that the product has a variation in particle size and a product having a sharp classification particle size curve cannot be obtained.

[0009]

In order to solve the above-mentioned problems, in the vertical crusher of the present invention, a vertical drive shaft rotatably supported at the center of the classifying chamber and integrally rotating around the drive shaft. A vertical pulverizer, comprising a rotary separator comprising a large number of flat plate-shaped classification blades, and a pulverizer for pulverizing the raw material by a rotary table below the classifying chamber and a pulverizing roller pressed on the rotary table and driven to rotate. The classifying blade has an inclination angle that increases in diameter from the lower side to the upper side in a side view, and is formed such that an outer diameter side of the classifying blade is receded in a rotation direction as compared with an inner diameter side in a plan view, In addition, the retreat angle of the classifying blade is different between the upper half and the lower half.

[0010]

According to the separator of the present invention, the classifying blades of the separator are divided into an upper stage and a lower stage, and the retreat angle of the upper stage and the lower stage (the angle formed by the blade angle with the radial direction) is changed. Since the sweep angle is set so that the classification particle diameter determined by the average radius of the classifier blades and the number of revolutions is the same, a product with a sharp particle size distribution with less variation in the particle size distribution of the classified product is obtained. Can be

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 6 relate to the present invention, FIG. 1 is a vertical cross-sectional view of a separator, FIG. 2 is a schematic vertical cross-sectional view of a separator, FIG. 3 is a plan view of an upper classifier blade of III-III in FIG. FIG. 5 is a plan view of the lower classifier blade as viewed from IV-IV in FIG. 2, FIG. 5 is an explanatory diagram illustrating a model of particles flowing into the classifier blade, and FIG. 6 is a correlation diagram between the classifying blade receding angle and the classifier particle diameter. .

In the figure, a separator 13 comprises a plurality of upper classifying blades 13A and lower classifying blades 13B disposed around a rotating shaft 13C which rotates vertically on the central axis of the vertical mill 1 and a classifier. Blades 13A and 13B and rotating shaft 13
C, an upper support 13E and a lower conical cone 13F, and upper and lower donut plates 13G and 13H and a donut plate 13D for separating the classifying blades 13A and 13B substantially at the center. Below the separator 13, an inverted conical guide cone 13J for guiding the dust-containing gas rising from the lower crusher to the separator 13 is fixed to the casing 1b via a support 13K. The top of the separator 13 is provided with a plurality of circumferentially and radially disposed impingement vanes 13L of coarse powder on the upper surface of the donut plate 13G. Shielding plates 1c and 1d are fixedly suspended from the casing 1b of the separator on the outer circumferential side and the circumferential side of the anti-dive blade 13L.

The classifying blades 13A and 13B have the same rotational speed Nr.
Although it rotates at pm, the air volume Q of the dust-containing gas rising from the vertical crusher 1 due to the shape of the vertical crusher 1 is generally equally divided into the upper classifying blade 13A and the lower classifying blade 13B. not distributed to, and each air volume Q _1, different and so the air volume Q ₂ values as shown in FIG. And generally Q
_2> is _{Q 1,} the air volume _{Q 2} According to the actual measurement is approximately 2 times the air volume _{Q 1.} In addition, since both of the classifying blades 13A and 13B have a structure in which the diameter increases (inclined angle θ) as they go upward in side view, the average radii R ₁ and R _{2 of} the upper and lower classifying blades are also different (R ₁ >). R ₂ ). H ₁ and H ₂ are the heights of the upper and lower classifying blades, and usually H ₁ = H ₂
It is. As described above, in order to obtain the same classification particle diameter in the classification operation of the upper and lower classification blades, FIGS.
As shown in ( ₁₎ , one method is to select the retreat angles α ₁ and α ₂ of the upper stage and the lower stage to different values instead of the same value.

Next, the classification mechanism of the classification blade will be described. FIG. 5 is a model diagram showing the force acting on the particles in the dust-containing gas passing between the classifying blades. In the figure, Vb is the speed of the classifying blade, Vg is the inflow gas speed, and α is the sweepback angle (β
Is the complementary angle of α), and R is the radius at the position of the particle. When the particle is subjected to three forces shown in FIG. 5, ie, gas wind pressure F ₁ , centrifugal force F ₂ , and centripetal force F ₃ , The diameter d of the particle when these three forces are balanced is the classified particle diameter. The following equation is obtained from the force balance equation.

[0015]

(Equation 1)

In equation (1), F ₁ = AρVb ² / 2g, F
^{_{2 = mRω 2, F 3 =}} C D AρVg 2 / 2g, ω = 2π
By substituting N / 60, C _D = 24 / Re, R = ρVgd / η, particle specific weight γ = 3000 kg / m ^3, etc., equation (2) for obtaining the classified particle diameter d is obtained.

[0017]

(Equation 2)

FIG. 6 is obtained as a result of performing a simulation trial calculation by applying equation (2) to a model number of an actual machine. FIG. 6 shows the receding angle α (recessive angle β as a parameter) on the horizontal axis and the classified particle diameter d on the vertical axis.
In the case of 200 and 300, the correlation between the retreat angle α (retreat angle β) of the classifying blade and the classifying particle diameter in the upper part (curves A, C, E) and the lower part (curves B, D, F) is shown. according to this,
When the standard rotation speed (design rotation speed) N = 200 rpm and the classification particle diameter of a required product is 28 μm, the retreat angle α ₁ of the upper classifying blade 13A is 30 ° (recessive angle β ₁ = 60).
°), if the retreat angle α ₂ of the lower classifying blade 13B is selected to be 50 ° (retreat angle β ₂ = 40 °), the same classified particle diameter can be obtained in the upper and lower stages. In the above simulation calculation, Q ₁ = 430 m ³ / mi from the past solid line measurement results.
n, Q ₂ = 870 m ³ / min.

As described above, the reversing angle α of the upper and lower classifying blades of the upper and lower classifying blades is selected so that substantially the same particle size can be obtained in the upper and lower stages. Rather than dividing the upper and lower stages into two, dividing them into multiple stages of three or more, and selecting the receding angles of the classifying blades in each stage so that they have the same classified particle diameter by simulation calculation, better classification results can be obtained. can get.

[0020]

As described above, in the separator of the vertical pulverizer of the present invention, the classifying blade has an inclination angle toward the upper side which expands the diameter in a side view, and has a receding angle in a plan view. In addition, since the sweep angles of the upper and lower stages are selected so as to have substantially the same classified particle diameter, the product after classification can be obtained with excellent dispersion having a sharp classification particle size distribution with little variation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a separator of a vertical pulverizer of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a separator according to the present invention.

FIG. 3 is a plan view according to III-III of FIG. 2 according to the present invention;

FIG. 4 is a plan view according to the present invention taken along line IV-IV of FIG. 3;

FIG. 5 is an explanatory diagram showing a model of particles flowing into a classification blade according to the present invention.

FIG. 6 is a correlation diagram between the sweepback angle of the classification blade and the classification particle diameter according to the present invention.

FIG. 7 is an overall vertical sectional view showing an embodiment of a conventional vertical crusher.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical grinder 1a Main body casing 1b Separator casing 1c Shield plate 1d Shield plate 3A Rotary table 4 Crush roller 13 Separator 13A Classification blade (upper) 13B Classification blade (lower) 13C Rotating shaft 13D Donut plate (intermediate) 13E Support 13F Conical cone 13G Donut plate (upper end) 13H Donut plate (lower end) 13J Guide cone 13K Support 13L Anti-dive feather

Claims (1)

(57) [Claims] 1. A classification system comprising: a vertical drive shaft rotatably supported at the center of a classifying chamber; and a rotary separator comprising a plurality of plate-shaped classifying blades integrally rotating therearound. In the vertical pulverizer in which the raw material is pulverized by a rotary table and a pulverizing roller which is pressed on the rotary table and driven to rotate, the classifying blade has an inclination angle which increases in diameter from below to above in a side view. In addition, the outer diameter side is formed to be receded in the rotation direction as compared with the inner diameter side in plan view of the classification blade, and the retreat angle of the classification blade is different between the upper half and the lower half. Vertical crusher.