JPH0738973B2 - Classifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The classifying device of the present invention relates to a classifying device for centrifugally classifying solid particles of a dust-containing gas that is a solid-gas two-phase fluid.
It is a classifier used in the coal industry, chemical industry, food industry and other industrial fields handling powder, and is particularly suitable for classifying products after ultra-fine pulverization.

[Prior Art] A vertical crusher equipped with a rotary table and a crushing roller is widely used as a kind of crusher for finely crushing granular materials such as cement raw materials, coal, and chemicals into powder. This type of crusher is a disk-shaped rotary table that is driven by a motor with a speed reducer and rotates at a low speed in the lower part of a cylindrical casing, and is pressed by hydraulic pressure or the like to a portion that equally divides the outer peripheral portion of the upper surface in the circumferential direction. And a plurality of rollers that are driven to rotate.

For example, in FIG. 4 showing a conventional vertical crusher, the crusher generally designated by reference numeral 1 is formed as a single tower in appearance, and the base thereof has a rotary table 3 rotated by an electric motor (motor) 2. Are arranged. A plurality of conical grinding rollers 4 are arranged so as to rotate in sliding contact with the rotary table 3, and the grinding rollers 4 are rotatably supported by a support arm 5. Support arm 5
Is a support shaft 6 which is rotatably supported on the crusher side at its center.
The support arm 5 extends downward through the side of the casing 8 surrounding the rotary table 3 and faces the lower space of the crusher. The lower end of the rotating arm 5 is rotatably supported by the tip of a rod of a pressure cylinder 9 whose lower end is rotatably supported by the base of the crusher 1. Reference numeral 10 indicates a coupling.

The granules as the raw material supplied from the raw material supply device (not shown) to the center of the rotary table 3 through the supply pipe 11 are the roller 4 and the rotary table 3 which are driven by the rotation of the table.
It is bitten in between and crushed. On the other hand, hot air is introduced into the casing 8 by a duct (not shown), and the hot air is blown up from the annular space 12 between the outer peripheral surface of the rotary table 3 and the inner peripheral surface of the casing 8. , The fine powder rises in the crusher 1 while being dried, and the classification device 10
After passing through 0, it is discharged from the discharge port 13 as a mixture with hot air and sent to the next step.

Fig. 3 shows the overall system diagram of the vertical crusher with a built-in classifier, which is crushed by the vertical crusher 1, classified by the classifier 100 and entered into the cyclone 200, where the powder collected and collected. Becomes a product, and the gas is released to the atmosphere via the suction fan 300, but the product contains a mixture of particles A that have passed through the rotor 110a and particles B that have passed through the labyrinth seal 120 and the gap 130.

It should be noted that some of the coarser particles ascend in the crusher 1 as well, but they are classified by the upper classifying device 100 and the rotary table 3
Returned to the top.

Further, the rotary table 3 has a rotary shaft (not shown) extending vertically downward, and the rotary force of the motor 2 is reduced in the reducer casing indicated by reference numeral 2A.
In addition to the speed reducer transmitting to the rotary shaft of
A thrust bearing mechanism and a radial bearing mechanism for supporting the rotary shaft are provided (both not shown).

On the other hand, the classifying device 100 is composed of a rotor 110 attached to the lower end of a vertical rotary shaft 110b and a variable speed electric motor 110c that rotates a plurality of blades 110a arranged on the outer periphery of the rotor 110 via the rotary shaft 110b. A mechanical seal 120, for example, a labyrinth seal is provided between the rotor and the housing 1a to minimize the leak gas from the gap 130.

[Problems to be Solved by the Invention] In a centrifugal force type classifying device having a rotor rotating at high speed, there is always a minute gap between the rotor and the outer housing. The particles pass through and merge with regular fine particles below the classification point that have passed through the rotor, resulting in a rough classification point and a change in the particle size distribution. For this reason, the maximum particle size of the product becomes large, and the evaluation of the entire product deteriorates.
This is a fatal defect when using ultrafine powder as a product.

If a contact-type sealing method is adopted in place of the non-contact type labyrinth seal mechanism for this minute gap in order to alleviate the above problems, the following drawbacks are exposed.

(1) When a contact type seal, for example, an oil seal is adopted, the peripheral speed is limited to 15 m / s, and when rotating at a higher speed, the sliding part generates heat and the function and life are significantly reduced. Therefore, although the oil seal method can be adopted for a small classifier, it cannot be used for a medium or large classifier because of its high speed.

(2) If the contact type seal structure is adopted for the rotor system that rotates at high speed, the rotational torque becomes very large due to the frictional force of the sliding part, the capacity of the motor must be increased, the equipment cost also increases, and the running cost of electricity is high. Basic unit also deteriorated (increased)
To do.

As described above, since the contact type cannot be substituted, the present invention adopts a non-contact type labyrinth seal structure and takes measures against deterioration of product quality (particle coarsening and particle size distribution change) due to leak air. .

[Means for Solving the Problems] In order to solve the above problems, the classification device of the present invention has a centrifugal force including a classification blade that has a vertical rotation axis and that is interposed between a pair of upper and lower disks. In the classifier, an opening is provided in the fine powder discharge duct after classification over the entire circumference in a direction perpendicular to the rotation axis of the classifier, and a disc and a cylinder facing the opening are provided on the upper disc of the classifier. By fixing the rotor composed of
A plurality of fins are arranged on the upper surface and the lower surface of the disk of the rotary blade so as to recede outward along the rotation direction of the disk.

[Operation] In the classification device of the present invention, the dust-containing gas containing coarse powder before classification that has passed through the minute gap between the rotor and the housing of the classification device is discharged by the centrifugal action of the fins attached to the disc of the rotor blade. Since it is discharged to the outside from the opening of the duct,
Since it does not merge with the exhaust path of the dust-containing gas after passing through the rotor of the classifier, the powder of both dust-containing gases can be made into a product without being mixed, so the desired fine powder does not become coarse. Absent.

[Examples] Hereinafter, details of the classification device of the present invention will be described with reference to the drawings.

1 and 2 show an embodiment according to the present invention, FIG. 1 is an enlarged longitudinal sectional view of a main part of a classification device, and FIG. 2 is a plan view taken along line II-II of FIG.

In the figure, 100 is a classifier, 101 is a casing of the classifier, 102 is a fine powder discharge duct, 110 is a rotor, 110a is a classifying blade, 110b is a rotary shaft, 110d is an opening, 120 is a labyrinth seal, 130 is a minute gap, 140 Is a rotary blade, and 140a and 140b are fins attached to the upper and lower surfaces of the disk of the rotary blade, respectively.

As described above, the classifying device 100 is a rotor fixed to the lower end of the vertical rotating shaft 110b and having a plurality of blades 110a on the outer circumference.
The structure is such that the variable speed electric motor 110c can rotate the 110 around the vertical axis at an arbitrary number of rotations, and a labyrinth seal 120 is arranged in the gap between the upper surface of the rotor 110 and the lower surface of the housing 1a.

The exhaust gas duct 102 has an opening 102a over the entire circumference.
2 is provided, and a rotary blade 140 composed of a disc and a cylinder facing the opening 102a is fixed to the upper disc of the rotor 110, and the upper and lower circumferences of the disc are shown in FIG. As described above, the fins 140a and 140b are arranged so as to recede obliquely outward along a plurality of rotation directions.

Therefore, when the classification device is operated, that is, when the rotor 110 is rotated around the vertical axis as shown in the figure, the suction force of the suction fan 300 causes the dust-containing gas to pass through the classification blades 110a of the rotor 110 of the classification device 100. In addition to the gas (LINE A), it branches to the dust-containing gas (LINE B) that contains coarse powder that passes through the labyrinth seal 120 and escapes to the outside through the fins 140b.
On the other hand, the dust-containing gas in the fine powder exhaust gas duct 102 is the fin 140a.
There is a small amount of dust-containing gas (LINE C) that passes through and escapes to the outside.

With the above configuration, in the present invention, the dust-containing gas of LINE B containing coarse powder that does not pass through the classification blade 110a is discharged to the outside via the fin 140b, and the refined powder after classification (LINE A)). In addition, even if the rotation speed of the rotor 110 of the classification device is low and the centrifugal action of the fins 140b is weak and the flow of LINE B flows backward, only clean air of the outside air enters the device and the product grain size becomes coarse. There is no.

On the other hand, if the dust-containing gas containing the powder C flowing through the fins 140a on the upper surface of the disc of the rotor blade 140 becomes too large, it will be finely pulverized, and the desired fine powder after classification will escape to the atmosphere. This is a product loss, and in order to avoid this, the negative pressure in the fine gas exhaust gas duct 102 by the suction fan 300 and the fins 140a
It is desirable to properly select the inclination angle and the number of fins according to the number of rotations of the classifier so that the gas discharge force due to the centrifugal action is balanced. Therefore, in the embodiment of the present invention, the mounting inclination angles θ (illustrated in FIG. 2) of the fins 140a and the fins 140b are the same, but they may be different vertically.

[Effect of the Invention] In the classifying device of the present invention, since the coarse powder of the seal portion is not mixed in the product composed of the regular fine powder that has passed through the rotor, the product quality is stable and the coarse powder is A high-quality ultrafine-milled product that does not mix with or a product having a desired particle size composition can be obtained.

Further, since the non-contact type seal is used, the rotating torque is small and the running cost can be reduced.

[Brief description of drawings]

1 and 2 show an embodiment according to the present invention, FIG. 1 is an enlarged longitudinal sectional view of an essential part, FIG. 2 is a plan view of FIG. 1 taken along line II-II,
3 to 4 show an embodiment of a vertical crusher having a conventional classifying device, FIG. 3 is an overall system diagram, and FIG. 4 is an overall longitudinal sectional view. 1 ... Vertical crusher, 1a ... Housing, 3 ... Rotating table, 4 ... Grinding roller, 100 ... Classifying device, 110 ... Rotor, 110a ... Classifying blade, 110b ... Rotating shaft, 110c ... … Variable speed motor, 110d …… Opening, 120 …… Labyrinth seal, 130 …… Micro gap, 140 …… Rotary blade, 140a …… Fin, 140b …… Fin, 200 …… Cyclone, 300 …… Suction fan, A ...... Powder after passing through the rotor, B ... Powder after passing through the labyrinth seal, C ... Powder after classification (fine powder), LI
NE A ... Powder A route, LINE B ... Powder B route, LINE C ...
Path of powder C.

Claims (1)

[Claims] 1. A centrifugal force type classifier having a vertical rotation axis and a classification blade interposed between a pair of upper and lower discs, wherein a fine powder discharge duct after classification is perpendicular to the rotation axis of the classification apparatus. An opening is provided over the entire circumference in the direction, and a rotary blade composed of a disk and a cylinder facing the opening is fixed to the upper disk of the classifier, and the upper surface of the disk of the rotary blade and A classifying device in which a plurality of fins that recede outward along the rotation direction of the disc are arranged on the lower surface.