JPS6211902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel classification device for a vertical mill that can improve the classification efficiency of pulverized materials as much as possible.

[Prior Art] Vertical mills are generally used as devices for pulverizing cement raw materials, coal, etc. into desired fluids or powders. This type of mill is provided with a classification device that classifies and extracts the fluid pulverized by a pulverizing section such as a roller into a desired particle size or fineness.

However, the above-mentioned conventional classification apparatus had poor classification efficiency, and the desired degree of fineness could not be obtained.

The problems with the conventional device will be explained below with reference to FIG. 1, which is illustrated as an example.

The illustrated example shows a vertical mill that is widely used, and this vertical mill collects pulverized material (granules or powder) from a pulverized material b placed at the inner bottom of an upright cylindrical housing a. It is configured to be transferred to and taken out from the upper part of the housing a by means of a fluid such as hot gas.

A classification device d is provided in the vertical mill configured in this manner. This classification device d is connected to the housing a by a rotary drive shaft e suspended within the housing a.
It is constructed by attaching a blade f formed to cross the flow path formed by the flow path.

Therefore, the pulverized material fluidly transferred from the pulverizing section b to the take-out port c is transferred to the classifier d during the transfer.
During this passing process, the coarse particles in the pulverized material are repelled and classified by the rotating centrifugal force of the blades f constituting the classifier d.

[Problems to be Solved by the Invention] However, in the case of the above-mentioned classifier d, although the coarse particles in the pulverized material are repelled and classified by the blades f in the classifier d, the repelled coarse particles are now It is sufficient if the coarse particles are once returned to the crushing section b and re-pulverized, but most of the coarse particles simply fall by their own weight along the housing a and are repelled by the fluid transfer. Since it is not re-pulverized, it promotes a decrease in classification efficiency and a decrease in pulverization efficiency.

As shown in Japanese Patent Publication No. 33-740, the pulverized material is transferred upward by fluid transfer from the pulverizing section at the inner bottom of the vertical housing, and the pulverized material is guided from radially outward to inward at the upper part of the housing into an annular shape. The coarse particles are rotated through the arranged guide vanes, and when passing through the outlet passage whose cross-sectional area gradually decreases, the rotation is stopped by the blades and the coarse particles are extracted while being classified. A pulverizer has also been proposed in which the pulverizer is returned to the pulverizing section, but the classification efficiency is still insufficient.

The present invention was devised to effectively solve the above-mentioned problems, and its purpose is to be able to freely adjust the fineness of the pulverized material and to improve the classification efficiency as much as possible. The purpose of the present invention is to provide a classification device for a vertical mill that can perform the following steps.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following features: The pulverizer is transported upward by fluid transfer from the pulverizer in the lower part of the vertical housing, and the pulverizer is transported upwardly by fluid transfer from the pulverizer in the lower part of the vertical housing. The guided pulverized material is classified while being rotated through annularly arranged guide vanes, and the classified pulverized material is taken out from the outlet at the top of the housing, and coarse particles are collected using the guide vanes as the bottom outer periphery. In a vertical mill classification device in which the conical internal cone returns the flow to the crushing section, the swirling flow guided from the outside in the radial direction to the inside surrounded by the guide vane and the internal cone is directed downward. In order to form a multi-stage directing passage for directing to A classification rotary vane is provided in a passageway that communicates between the inside and the outlet.

[Function] The pulverized material to be fluid-transferred is firstly rotated by the guide vane and classified into the first classification, and then directed downward by the directional passage of the classification cone to be classified into the second classification.
Finally, a centrifugal force is applied by the classification rotary vane, resulting in a third classification.

[Embodiment] A preferred embodiment of the present invention will be described in detail below with reference to FIG. 2 and subsequent drawings.

In the figure, reference numeral 1 denotes a vertical mill that grinds raw material m, which is a material to be crushed such as cement raw material or coal, into a desired fluid or powder, and its upright cylindrical housing 2
It has a crushing part 3 at the inner bottom.

The crushing section 3 includes a rotary table 3a that is horizontally disposed so as to be freely rotatable so as to close the lower end opening of the housing 2, and a number of rotary tables provided on the rotary table 3a so as to be biased in the direction of gravity so as to be rotatable. It is composed of two rolling pressure rollers 3b. The upper center of the rotary table 3a is formed to bulge, and the rollers 3b are arranged so as to be inclined inward. While being crushed by the relative movement with 3b, the crushed material n
The structure is such that the particles are scattered in the radial direction by the centrifugal force of the rotary table 3a.

Further, the above-mentioned crushing section 3 has an upper central part of the rotary table 3a as an input section 4 for the raw material m, and a raw material supply chute 5 is attached to pass through the housing 2 so as to face the input section 4.

Inner peripheral wall 2a of housing 2 and rotary table 3a
A gap is formed between the outer periphery of the housing 2 and the gap is used as a spout 3c for spouting fluid such as hot gas, and the fluid spouted from the spout 3c moves the pulverized material n upward into the housing 2. It is adapted to transfer fluid.

Further, the housing 2 is formed in a shape that gradually expands from the approximately central portion to the top in the longitudinal direction, and
At the center of its upper end, an outlet 6 for taking out the crushed material n to be fluid-transferred is formed. The outlet 6 is formed at the upper end opening of an outlet tube 7 formed by forming the upper end of the housing 2 into a cylindrical shape with a small diameter.

A classification rotary vane 9 is rotatably provided in the extraction pipe portion 7 forming a passage portion 8 that communicates the interior of the classification cone and the extraction port 6, which will be described later. This classification rotary vane 9 classifies the pulverized material n fluid-transferred via a classification cone 10, which will be described later, by centrifugal force, and is attached to the rotating shaft 11a of a reducer 11 suspended within the passage section 8. It is designed to be rotationally driven by a motor M connected to a speed reducer 11. Further, the classification rotating blade 9 is designed to also perform a so-called exhaust function of sucking the inside of the housing 2.

On the other hand, on the inlet side of the passage portion 8, a classification cone 10 is installed in the housing 2, which forms a multistage directing passage 20 that directs the swirling flow guided inward from the radial direction via guide vanes 14, which will be described later, downward. It is formed so that it hangs inward. This classification cone 10 is formed by stacking classification cylinders 10a formed in the shape of a funnel with a diameter that covers the passage portion 8 in multiple stages (three stages in the illustrated example) in the vertical direction at appropriate intervals.
The pulverized material n flowing from an inlet 12 on its outer periphery, which will be described later, is classified by colliding with the classification cylinder 10a. Further, the classification cone 10 is vertically communicated with the passage portion 8 and is arranged such that its lowermost opening 10b faces the center of the rotary table 3a.

An introduction port 12 is formed at the outer periphery of the classification cone 10 configured in this manner so as to surround it. The introduction port 12 is formed by arranging the upper end of an internal cone 13 (described later), which is formed in the shape of a large diameter funnel so as to cover the classification cone 10, at an appropriate distance from the upper end wall of the housing 2.

As shown in FIG. 3, a plurality of guide vanes 14 are arranged annularly at appropriate intervals in the inlet 12 for imparting a swirling flow to the fluid containing the crushed material n flowing into the classification cone 10. These guide vanes 14... are all rotatably supported on the upper end wall of the housing 2, and are connected to a direction operating device 15 provided on the outside of the housing 2, and the angle can be adjusted via this direction operating device 15. It is structured so that it can be freely achieved.

On the other hand, the inner cone 13 formed in a funnel shape as described above is connected to the lowermost classification cylinder 10 of the classification cone 10.
It is disposed within the housing 2 at an appropriate distance from the inner circumferential wall 2a of the housing 2, surrounding the inner peripheral wall 2a. The internal cone 13 has a so-called double pipe structure inside the housing 2, and has a pulverized flow channel 16a flowing from the pulverizing section 3 to the inlet 12 on the outside, and a pulverized flow channel 16a flowing from the pulverizing section 3 to the inlet 12 on the inside, and a pulverized flow channel 16a flowing from the pulverizing section 3 to the inlet 12 on the inside, and a pulverized flow channel 16a flowing from the pulverizing section 3 to the inlet 12 on the inside,
It is provided to form a falling path 16b of n'.
Further, the lower end of the internal cone 13 is located approximately at the center in the longitudinal direction of the housing 2, and the lower end opening 13a faces the center of the rotary table 3a, that is, the raw material input section 4. Furthermore, a cone head 17 formed in the shape of a hollow cone is interposed inside the internal cone 13.
It is configured to reduce the blowing up force of the fluid flowing in from the lower end opening 13a of the tube, thereby preventing the classified coarse particles n' from being blown up.

In addition, the reference numeral 18 in Fig. 2 indicates the classified pulverized material.
This is a take-out duct connected to the take-out port 6 of the housing 2 to lead n' (milled powder) to the outside.

Next, the operation of the above embodiment will be described.

First, a flour milling line such as an exhaust fan or a flour collector is connected to the outlet duct 18, and this flour milling line is started to create a negative pressure inside the housing 2, and the spout 3c is opened inside the housing 2. A fluid such as hot gas is ejected from the Then, the classification rotary blade 9 is rotated by the motor M via the reducer 11, and the rotary table 3a and rollers 3b in the crushing section 3 are rotated to start the operation of the vertical mill 1.

Rotary table 3a via raw material supply chute 5
When raw material m is supplied to the upper raw material input section 4, raw material m
is pulverized into granules or powder between the rotary table 3a and the rollers 3b, and the pulverized material n is scattered toward the outer circumference by the centrifugal force of the rotary table 3a. It is scattered toward the outer circumference of the rotary table 3a.
The pulverized material n scattered in the outer circumferential direction of the rotary table 3a is blown up by the fluid ejected from the ejection port 3c, and is transferred to the upper introduction port 12 via the pulverized flow path 16a along the inner peripheral wall 2a of the housing 2. Ru. The fluid containing the pulverized material n is blown into the classification cone 10 from the inlet 12. Since the inlet 12 has a guide vane 14, the flow direction of the fluid containing the pulverized material n is controlled by the guide vane 14. The pulverized material n is first classified by swirling. This swirling flow collides with the classification cylinder 10a and is redirected downward by the directing passage 20, thereby separating coarse particles and performing a second classification. Note that the classified particle size can be adjusted by adjusting the angle of the guide vane 14.

Next, the fluid containing the crushed material n passes through each classification cylinder 10.
It flows upward into the classification cone 10 through the gap a.

Next, the passage portion 8 is opened from the inside of the classification cone 10.
In the process of transferring the fluid to the outlet 6 through
The pulverized material n is further classified into a third classification by the centrifugal force of the classification rotating blade 9 in the passage section 8, and the fine particles in the pulverized material n are separated to a predetermined particle size. Then, the pulverized product n' (milled powder) consisting only of extremely fine particles that has been finally classified by the classification rotating blade 9 is led to the milling line from the take-out duct 18.

On the other hand, the coarse particles to fine particles n' separated by the guide vane 14, the classification cone 10, and the classification rotary blade 9 fall due to their own weight, are guided by the internal cone 13, and enter the raw material input section 4 of the rotary table 3a. It will be returned.

Therefore, by sequentially and continuously classifying the pulverized material n in the three stages of the guide vane 14, the classification cone 10, and the classification rotating blade 9, the separated coarse particles to fine particles n' are re-classified into the pulverized material 3. Since the classification efficiency can be improved as much as possible, it is possible to obtain an initial fineness that could not be achieved with conventional equipment. Furthermore, by arbitrarily changing the angle of the guide vane 14 and the rotational speed of the classification rotary blade 9, the fineness can be freely adjusted. It is also possible to sufficiently cope with fluctuations in the flow rate of the fluid. Further, since the classification rotary blade 9 has a so-called exhaust function, it is possible to reduce the load on the exhaust fan connected to the downstream side of the take-out duct 18. In addition, since coarse particles and fine particles can be effectively introduced into the crushing section 3,
It is used for re-grinding material mechanism.

In the above embodiment, the take-out pipe 7 forming the passage portion 8 is formed into a cylindrical shape, but the take-out pipe portion 7 may be formed into a funnel shape. The classification function can be improved.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects can be obtained.

(1) The first classification is performed by generating a swirling flow using a guide vane, the second classification is performed by actively directing the swirling flow downward through the multistage directing passage of the classification cone, and the It is directed downward, and when it turns upward and heads toward the outlet, it is forcibly centrifuged by the classification rotary blade to perform the third classification, making it possible to improve the classification efficiency of the pulverized material as much as possible. .

(2) By changing the direction of the guide vanes and the rotational speed of the classification rotary vanes, the fineness of the pulverized product can be adjusted freely, and therefore it is possible to sufficiently respond to variations in the particle size of the raw material or the flow of the transfer fluid. I can do it.

(3) Therefore, according to the classification device of the vertical mill of the present invention, it is possible to obtain milled powder with initial fineness, and the reliability of this type of vertical mill is improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a conventional device, FIG. 2 is a schematic vertical cross-sectional view of a vertical mill showing a preferred embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line - in FIG. . In the figure, 1 is a vertical mill, 3 is a crushing section, 6 is an outlet, 8 is a passage section, 9 is a classification rotating blade, 10 is a classification cone, 12 is an inlet, 14 is a guide vane,
n is a pulverized product.

Claims (1)

[Claims] 1. The crushed material is transferred upward by fluid transfer from the crushing section in the lower part of the vertical housing, and is guided from the outside in the radial direction to the inside in the upper part of the housing. A classification device for a vertical mill, in which the classified pulverized material is taken out from an outlet above the housing, and coarse particles are returned to the pulverizing section through an inverted conical inner cone with the guide vane as the bottom outer periphery. In order to form a multistage directing passage that directs the swirling flow guided inward from the radial direction downward in the interior surrounded by the guide vane and the inner cone, the inverted conical classifying cylinder is moved up and down. A classification cone arranged at approximately equal intervals in the direction is provided so that the inside thereof communicates with the above-mentioned outlet, and a classification rotary vane is provided in a passage portion communicating the inside of the classification cone and the outlet. Vertical mill classification equipment.