JPH04330957A - Powder dispersing machine - Google Patents

Abstract

PURPOSE:To efficiently disperse a fine powder by the ejector action with a small-sized device by discharging a powder contg. flocculated grains from a cylindrical or annular narrow passage and a high-speed air flow from around the discharge port. CONSTITUTION:The outer peripheral wall of a nozzle 20 gradually decreases in diameter toward the lower part, and an annular small passage is formed between a body 11 and a tapered cylindrical part 12a. Accordingly, an annular opening surrounding the opening of the nozzle 20 is formed at the lower end of the nozzle 20. The annular opening is used as the blowoff port of the air flow supplied to a cavity 19 from the port 21 of the body 11, i.e., a high-speed air flow blowoff port producing an ejector effect. A powder passage connecting the lower opening 20a and an upper hopper part 22 is provided in the nozzle 20. A powder is appropriately supplied to the hopper part 22 from a feeder. As a result, the powder is efficiently dispersed by this small-sized device, and the deposition of the granular body on the side face of the outer wall is prevented.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a powder dispersion machine, and more particularly to a powder dispersion machine suitable for dispersing powder into single particles and performing pretreatment for supplying the particles to a classifier. .

0002

BACKGROUND OF THE INVENTION It is generally known that one of the factors that determines the classification performance of a wind classifier is the degree of dispersion of supplied powder in an air stream. In other words, if the degree of dispersion of powder particles in the airflow is low and the powder enters the classification chamber with a partially agglomerated state, the agglomerated state will naturally be classified as coarse particles, so it will naturally fall on the coarse powder side. This is because if the fine powder side is used as a classified product, the yield will decrease, while if the coarse powder is the product, fine powder will be mixed in.

[0003] For this purpose, a classifier generally has a mechanism for dispersing powder at the front stage of the classification chamber.

0004

[Problems to be Solved by the Invention] By the way, when the powder to be classified in a wind classifier is highly adhesive or cohesive, the ability of the dispersion mechanism within the classifier may not be sufficient. , for example, 1μ in ultrafine powder
If the weight of m or less exceeds 50%, the adhesion and cohesiveness of the powder particles will rapidly increase, increasing the risk of lowering the yield and causing adhesion and clogging at the supply port and the like.

[0005] Therefore, it has been considered to provide a separate classifier for powder dispersion upstream of the classifier, thereby increasing the degree of dispersion of the powder supplied to the classifier.

[0006] FIG. 1 shows an overview of the overall flow of an example of a wind classifier in which such a dispersing machine is arranged. The powder is provided so that the coarse powder side 5 is recovered via the rotary valve 4 and the fine powder side 7 is recovered via the back filter 6. Further, the blower 8 is used to draw air passing through the classifier into a suction state.

However, the dispersing machine 2 shown in FIG. 1 is a pre-processing device for the classifier 3, and if a known mechanical type dispersing machine is simply applied, for example, the supply to the classifier will be insufficient. It cannot be considered to be suitable for the purpose of improving the dispersion of the powder. The first reason is that, for example, in the case of a type that uses stirring blades, the path from the dispersion machine to the classifier is inevitably long to some extent, which leads to re-agglomeration in this path and reduces the dispersion effect. The second reason is that the powder to be treated is relatively diluted in the air flow and adheres to the wall surface, which hinders the continuous operation of the disperser and eventually the classifier. Furthermore, this type of mechanical type has the disadvantage that the device is large.

[0008] Based on the above, the present inventor investigated a powder dispersion machine suitable for converting agglomerated particles into single particles as a pretreatment when supplying powder containing agglomerated particles to an air classifier. The present invention has been accomplished in combination, and an object of the present invention is to provide a powder dispersion with a simple structure that can efficiently disperse the powder to be treated by utilizing the ejector effect of high-speed air flow. It is in the place where the machine is provided.

[0009] Another object of the present invention is to provide an air flow containing dispersed powder into single particles so that it is directly sent to the supply port of the classifier without going through any other route, thereby preventing reagglomeration. The object of the present invention is to provide a small-sized powder dispersion machine that is directly connected to a classifier and whose influence is reduced as much as possible.

0010

[Means for Solving the Problems] A feature of the powder dispersion machine of the present invention that achieves the above object is that the powder containing aggregated particles supplied from the upstream side of a circular tube-shaped or annular narrow passage is transferred to the downstream side. A powder nozzle that discharges powder from a discharge port, a powder dispersion passage formed as a circular tube-shaped or annular narrow path downstream from the vicinity of the powder nozzle discharge port, and an outer periphery of the powder nozzle discharge port. and an annular high-speed airflow outlet that blows out a high-speed airflow in a direction that is inwardly inclined toward the downstream side of the powder dispersion passage.

[0011] The above-mentioned dispersing machine has a downstream part of the powder dispersion passage.
By directly connecting to the powder supply port of the classifier arranged at the next stage, the powder dispersion machine can be made suitable for processing before the wind classifier.

Further, the powder dispersion passage in the above structure may have a circular tube shape or an annular straight tube shape, but it may also be a circular tube shape whose diameter gradually increases toward the downstream, or a circular tube shape. The passage may have a gradually increasing diameter (radial). In order to form a passage in which the diameter of such an annular passage is gradually increased, for example, the discharge port of the powder nozzle is faced to the top of a conical wall body, and this conical wall is used as the inner wall. It can be formed by having inverted cone-shaped outer wall surfaces facing each other with a small gap on the outside. In addition, in the case of the powder dispersion passage of the type in which the diameter of the annular passage is gradually increased as described above, the conical member forming the inner wall surface shall be a rotating body that rotates around the central axis of the powder nozzle. is desirable from the viewpoint of preventing adhesion of powder particles.

[0013] According to the dispersion machine having such a configuration, efficient dispersion of the powder can be obtained by the ejector action of the high-speed air flow, and the high-speed air flow flows along the outer wall surface in the dispersion passage, so that the powder is dispersed. Particle adhesion is effectively prevented. In addition, by directly connecting the dispersion passage to the next classifier, there is no need for an intermediate passage, which has the advantage of preventing particle re-agglomeration and downsizing the device.Moreover, the degree of dispersion is determined by the flow rate of the high-speed air flow. Another advantage is that it can be easily changed by adjusting the air pressure.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on embodiments shown in the drawings.

FIG. 2 shows an embodiment of a dispersing machine having a circular tube-shaped powder dispersion passage. The body (I) has a vertical cylindrical through hole 12 formed in its central portion. The upper part of the through hole 12 has a tapered cylindrical part 12a whose diameter gradually increases upward, and the powder dispersion passage 12b which continues downward through the constriction part has a diameter which increases in the opposite direction. It is designed to increase gradually. Also this body (
I) In 11, a female thread 15 is formed on the outer periphery of an annular flange 14 provided on the outside of the main body 13 and protruding upward;
A body (II) 16 described below is provided so as to be screwed onto it.

The body 16 has a circumferentially protruding flange 17 at its lower end, and the body (I) 11 is attached to the outer periphery of the flange 17.
A male thread 18 is formed to be screwed into the female thread 15 of the body (I), and a recessed portion in the center is provided to sealably fit into the outer periphery of the main body portion 13 of the body (I) to form a cavity 19. Furthermore, a nozzle 20 that projects downward and enters the tapered cylindrical portion 12a of the body 11 is provided at the center of the recess. This nozzle 20 has an outer circumferential wall that gradually decreases in diameter toward the bottom, thereby forming an annular small passageway with the tapered cylindrical portion 12a of the body 11. Therefore, at the lower end of the nozzle 20, It forms an annular opening surrounding the opening of the nozzle. This annular opening forms an outlet for the airflow supplied from the port 21 of the body 16 to the cavity 19, that is, a high-speed airflow outlet that produces an eject effect.

The nozzle 20 also has a powder passage extending from an opening 20a at the lower end to a hopper section 22 at the upper end. Powder is appropriately supplied to the hopper section 22 from a feeder (not shown).

In the figure, reference numeral 25 denotes a conical body fixed to the upper surface of the rotating classification rotor 25, the top of which is provided so as to face the powder dispersion passage. 27 is a seal ring.

In the above configuration, while supplying powder to the hopper section 22, the port 21 supplies powder to the hopper section 22, for example, 3.0k.
By supplying pressurized air of gf/cm2 and supplying powder air flow to the classifier 23 at the same time as dispersion, the nozzle 2
It has been experimentally confirmed that the powder discharged from the opening of the nozzle 20 is effectively dispersed due to the ejection effect caused by the high-speed air flow blown from the surrounding opening at the lower end of the nozzle. That is, for example, in the case of calcium carbonate powder, the yield on the fine powder side is improved compared to when the dispersion machine of this example is not used.
5 to 85%), it was difficult to classify due to clogging that occurred during classification, but when used in conjunction with the dispersion machine in this example, it is possible to perform classification processing by continuous operation of the device, making classification easier. Regarding the efficiency, 98% recovery of particles of 1 μm or less was achieved on the fine powder side.

In addition, κ=(D
P25 )/(DP75 ) (DP25=25%
Separation diameter (DP75 = 75% separation diameter, the closer κ is to 1, the better) varies from κ = 0.52 to κ depending on the presence or absence of the disperser in this example.
=0.60.

[0021] These are because the powder flow that passes through the disperser of this example enters the classifier immediately without passing through an intermediate path, so reagglomeration is less likely to occur, and at the same time, it prevents adhesion to the walls at the powder supply port, etc. This is considered to be a person based on reasons such as the fact that the In addition, the dispersion machine of this example has an extremely simple and compact structure, which has advantages in terms of equipment, and because it uses an ejector system, it also has the advantage of not being affected much by load fluctuations on the powder supply side. It is something.

[0022] The diameter, blowing direction, length and shape of the high-speed air outlet surrounding the opening of the nozzle 20 may be changed as appropriate depending on the properties of the powder to be treated, the processing capacity, etc. However, in general, the blowing direction of the high-speed air flow should preferably form an inward acute angle of 45 degrees or less with respect to the direction of powder discharge from the nozzle, and in particular, the blowing direction should be along the powder discharge direction as much as possible. This is effective in preventing powder from adhering to the wall.

The embodiment shown in FIG. 3 is an improved version of the one shown in FIG. 2, in which the powder dispersion passage is inserted into the classifier, thereby reducing the possibility of reagglomeration after dispersion. The aim is to further reduce this and improve dispersion efficiency. In this embodiment, members that are functionally the same as those in FIG. 2 are designated by the same reference numerals.

The feature of this example is that the body (I) with reference numeral 11 is not directly fixed to the classifier 23, but is indirectly fixed through screw fitting to the fixed disk 30.
1 is that the classifier can be finely adjusted in the vertical direction, and the nozzle 20 is attached as a separate item to the lower end of the body 16, and the lower end of the nozzle is arranged to face each other in a conical shape. , a radial powder discharge port is formed between the surface of the conical body 26 in the classifier, and therefore the powder dispersion passage 12b formed by the body 11 also has a downwardly widening shape, There are two points: the passage is constructed by cooperating with 26, and other points are substantially the same as the embodiment shown in FIG.

In the figure, reference numeral 31 is a female screw formed in the disk 30, and by screwing the male screw 32 of the body 11 into this, vertical adjustment is possible.
The amount of gap between the inner cone body 26 and the inner cone body 26 can be adjusted as necessary. Also, 33 and 34 are seal rings, 3
Reference numerals 5 and 36 indicate screw holes for fastening bolts.

[0026] Even in a dispersing machine having such a configuration, the same effects as in the case shown in Fig. 2 can be obtained, and moreover, in the case of this example, the powder dispersion passage substantially penetrates into the classifier. Therefore, even better dispersion effects can be expected.

[0027]

Effects of the Invention As described above, the powder dispersion machine of the present invention has the various effects mentioned above as a relatively small device, that is, it can efficiently obtain powder in a dispersed state by the ejector action, and A high-speed airflow flows on the wall surface, which prevents powder particles from adhering to the wall, and if the powder dispersion passage is directly connected to the next stage of equipment, there is no intermediate path, which prevents the dispersed powder from re-agglomerating. You can also get the effect of being Furthermore, since it uses an ejector system, it has the effect of not being affected much by load fluctuations on the powder supply side, which is extremely useful.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the overall flow of a wind classifier system equipped with a disperser according to the present invention.

FIG. 2 is a longitudinal sectional view of a disperser according to an embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a disperser according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Feeder, 2... Dispersion machine, 3... Classifier, 4... Rotary valve, 6... Back filter, 11... Body I, 12a... Tapered cylinder part, 1
2b...Powder dispersion passage, 16...Body II, 19
...Vacancy, 20...Nozzle, 21...Port, 2
2... Hopper part, 23... Classifier, 24... Powder supply port, 25... Classifying rotor, 26... Cone,
30...Disk.

Claims (1)

[Scope of Claims] 1. A powder nozzle that discharges powder containing aggregated particles supplied from the upstream side of a circular tubular or annular narrow passage from a downstream discharge port, and a powder nozzle that discharges powder containing aggregated particles supplied from the upstream side of a circular tube-shaped or annular narrow path, and A powder dispersion passageway formed as a circular tubular or annular narrow passage towards the powder nozzle, and a high-speed air flowing in a direction inwardly inclined from the outer periphery of the discharge port of the powder nozzle toward the downstream side of the powder dispersion passageway. A powder dispersion machine characterized by being equipped with an annular high-speed air flow outlet that blows out a flow. 2. The powder dispersion machine according to claim 1, wherein the diameter of the circular tubular powder dispersion passage gradually increases toward the downstream. 3. Claim 1, wherein the annular powder dispersion passage has a diameter that gradually increases toward the downstream.
Powder dispersion machine described in section.