DE-112017004019-B4 - Classification device

DE112017004019B4DE 112017004019 B4DE112017004019 B4DE 112017004019B4DE-112017004019-B4

Abstract

Classification device comprising a plurality of blades arranged at suitable intervals in the circumferential direction and arranged radially or eccentrically, and a rotor with classification chambers between the blades, by which fine particles in a fluid are classified such that, as a fluid flows into the classification chambers from the outer circumferential side to the inner circumferential side, particles larger than a separation particle size are moved to the outer circumferential side and particles smaller than the separation particle size are moved to the inner circumferential side, characterized in that the blades have a constant height in the direction of rotation of the rotor and the thickness increases towards the outer circumference in the circumferential direction, wherein the thickness t(d) of the blades at the position of the diameter d of the classification chambers can be determined by the following equation 15: t ( d ) = 1 N [ π d − Q T × 1 D 1 2 × 2 × 894 d ⋅ n 2 × 18 η 9.8 ( ρ 2 − ρ 1 ) ] where Q: the flow rate, N: the number of classification chambers in the circumferential direction, D 1 : the particle size, n : the rotational speed of the rotor, η : the viscosity of the fluid, ρ 1 : the specific gravity of the fluid, ρ 2 : the specific gravity of the particles and T : the height (constant) of the blades.

Inventors

Mitsugi Inkyo
Makoto Sato
Masaaki Ogihara

Assignees

Mitsugi Inkyo
SATAKE CHEMICAL EQUIPMENT MFG LTD.

Dates

Publication Date: 20260513
Application Date: 20170808
Priority Date: 20160809

Claims (4)

Classification device comprising a plurality of blades arranged at suitable intervals in the circumferential direction and arranged radially or eccentrically, and a rotor with classification chambers between the blades, by which fine particles in a fluid are classified such that, as a fluid flows into the classification chambers from the outer circumferential side to the inner circumferential side, particles larger than a separation particle size are moved to the outer circumferential side and particles smaller than the separation particle size are moved to the inner circumferential side, characterized in that the blades have a constant height in the direction of rotation of the rotor and the thickness increases towards the outer circumference in the circumferential direction, wherein the thickness t(d) of the blades at the position of the diameter d of the classification chambers can be determined by the following equation 15: t ( d ) = 1 N [ π d − Q T × 1 D 1 2 × 2 × 894 d ⋅ n 2 × 18 η 9.8 ( ρ 2 − ρ 1 ) ] where Q: the flow rate, N: the number of classification chambers in the circumferential direction, D 1 : the particle size, n : the rotational speed of the rotor, η : the viscosity of the fluid, ρ 1 : the specific gravity of the fluid, ρ 2 : the specific gravity of the particles and T : the height (constant) of the blades.
Classification device according to Claim 1 , where the thickness t(d) of the blades is equal to 0 at the inner circumference of the blades.
A classification device comprising a plurality of blades arranged at suitable intervals in the circumferential direction and arranged radially or eccentrically, and a rotor with classification chambers between the blades, by which fine particles in a fluid are classified such that, as a fluid flows into the classification chambers from the outer circumferential side to the inner circumferential side, particles larger than a separation particle size are moved to the outer circumferential side and particles smaller than the separation particle size are moved to the inner circumferential side, characterized in that the classification device has a rotor in which the thickness of the blades is fixed in the circumferential direction and the height in the direction of rotation of the rotor is increased towards the inner circumference, wherein the height T(d) of the blades at the position of the diameter d of the classification chambers satisfies the following equation 11: T ( d ) = Q π d − tN ⋅ 1 D 1 2 × 2 × 894 d ⋅ n 2 × 18 η 9.8 ( ρ 2 − ρ 1 ) where Q: the flow rate, N: the number of classification chambers in the circumferential direction, D 1 : the separation particle size, n : the rotational speed of the rotor, η : the viscosity of the fluid, ρ 1 : the specific gravity of the fluid, ρ 2 : the specific gravity of the particles and t : the thickness of the blades.
A classification device comprising a plurality of blades arranged at suitable intervals in the circumferential direction and arranged radially or eccentrically, and a rotor with classification chambers between the blades, by which fine particles in a fluid are classified such that, as a fluid flows into the classification chambers from the outer circumferential side to the inner circumferential side, particles larger than a separation particle size are moved to the outer circumferential side and particles smaller than the separation particle size are moved to the inner circumferential side, characterized in that, on the one hand, the height of the blades is increased towards the inner circumference in the direction of rotation of the rotor, and on the other hand, the thickness increases towards the outer circumference in the circumferential direction. is formed, whereby the height T(d) and the thickness t(d) of the blades at the position of the diameter d of the classification chambers can be determined using the following equations 18, 19 and 21: T ( d ) = Q E ( d ) ⋅ N ⋅ 1 D 1 2 × 2 × 894 d ⋅ n 2 × 18 η 9.8 ( ρ 2 − ρ 1 ) E ( d ) = π N ⋅ { b ⋅ d 2 − b ⋅ d 2 − a ⋅ d 1 d 2 − d 1 × ( d 2 − d ) } t ( d ) = π d N − π N ⋅ { b ⋅ d 2 − b ⋅ d 2 − a ⋅ d 1 d 2 − d 1 × ( d 2 − d ) } where a: the interspace coefficient (πd 1 -Nt 1 )/πd 1 between the inner circumferential blades, b: the interspace coefficient (πd 2 -Nt 2 )/πd 2 between the outer circumferential blades, d 1 : the inner circumferential diameter of the rotor, d 2 : the outer circumferential diameter of the rotor, t 1 : the inner circumferential thickness of the blades, t 2 : the outer circumferential thickness of the blades, Q : the flow rate, N : the number of classification chambers in the circumferential direction, D 1 : the separation particle size, n : the rotational speed of the rotor, η : the viscosity of the fluid, ρ 1 : the specific gravity of the fluid and ρ 2 : the specific gravity of the particles.

Description

[Technical field] The present invention relates to a device that classifies fine particles in a gas or a slurry. [Background technology] There are dry classification devices that have a rotor 2, in which, as in 1 As shown, blades 1 are arranged circumferentially at a uniform distance, radially from the center of rotation or eccentrically from the center of rotation, and classify fine particles in the air by rotating the rotor 2 at a high speed, as well as moisture classification devices for classifying fine particles in a slurry. 2 Figure 1 shows the schematic overall structure of a classification system comprising a dry classification device 3, which includes the rotor 2 internally. A material feed device 5 supplies the classification device 3 with material along with air. The material is classified into coarse and fine material by the rotor 2, which rotates at high speed. The coarse material is discharged from the classification device 3 and collected in a container 6, while the fine material passes through an outlet chamber 8 surrounding a drive shaft 7 coupled to the rotor 2 and flows into a bag filter 11. In the bag filter 11, the fine material is separated from the air and collected in a container 12. An example of such a dry classification device is disclosed in the following patent document 2. 3 Figure 1 shows the schematic overall structure of a classification system comprising a wet classification device 14. A material slurry is fed to the classification device 14 from a slurry tank 15 by means of a slurry pump 16. A rotor 17 rotating at high speed classifies the material slurry into a coarse material slurry and a fine material slurry. The coarse material slurry is discharged from the machine by the classification device 14, while the fine material slurry passes through a hollow drive shaft 18 coupled to a rotor 17 and is collected in a tank 19. An example of such a wet classification device is disclosed in the following patent document 1. The classification at the in 1 The depicted rotor 2 is formed by the fact that, while a gaseous substance or a slurry (hereinafter referred to as "fluid") flows into the interior of the rotor 2 and moves towards the inner circumferential side, the particles in the fluid are subjected to a centrifugal force due to the rapid rotation of the rotor 2 and to a reaction due to the fluid flowing in the inner circumferential direction opposite to the direction of the centrifugal force. By means of a particle size that balances both forces, the particles are classified into coarse material with a large diameter and fine material with a small diameter. This is explained using particles 10 that are placed in arbitrary classification chambers 9 between the blades 1 of the rotor 2. 1 flow into the depicted rotor 2, which rotates at high speed. At the position of diameter d of the classification chambers 9, the particles 10 are subject to a centrifugal force F acting diametrically outwards, and, due to the flow of the fluid towards the inner circumferential side, to an opposing effect due to the flow resistance R, acting in the opposite direction to the centrifugal force F, assuming that the particles 10 are round, their diameter is given as D, the rotational speed of the rotor 2 as n, the specific gravity of the fluid as ρ 1 , the specific gravity of the particles 10 as ρ 2 and the gravitational acceleration as g, the centrifugal force F can be expressed by the following equation 1. F=16πD3⋅g(ρ2−ρ1)⋅0.001118n2⋅(d/2)=16πDa⋅9.8(ρ2−ρ1)⋅d⋅n22×894 On the other hand, the flow resistance R is expressed using Stokes' theorem by the following equation 2, given the viscosity as η and the inward linear velocity of the fluid as s: R=3π⋅D⋅η⋅s The linear velocity s can be determined by the following equation 3, where the arc area on the circumference of the circle is at the point of the diameter d. 1 The area of the classification chambers 9 shown (hereinafter referred to only as the circular arc area) is expressed as A, the number of classification chambers 9 in the circumferential direction as N, and the flow rate of the inwardly directed fluid as Q. s=QA⋅N Since the circular arc area A shown in equation 3 results from the multiplication of the length of the circular arc on the circumference at the position of the diameter d and the length (height) of the rotor's axis of rotation, and since the classification chambers are present as a plurality, namely N ≤ 1, the circular arc and its chord length are small, so that this is an approximation of the product of the chord length in the form of the cross-sectional area at the chord and the length (height) of the rotor's axis of rotation. Therefore, in the present description, both are considered essentially identical. Similarly, with regard to the thickness of the blades in the circumferential direction at the position of the diameter d (hereinafter referred to as "thickness of the blades") and the chord, as well as the gap, the arc length an