JPH09108626A - Method for screening powdery and granular materials and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for screening powdery and granular materials by which the efficiency in classifying all kinds of powdery and granular materials is remarkably improved, the structure is made compact, the installation space is effectively utilized and the equipment cost is reduced. SOLUTION: A raw material 10 consisting of powdery and granular materials is dropped on a slider chute 13 and screened into a fine-grain material and a coarse-grain material through the opening 15a of the bar screen 15 provided on the lower extension of the chute 13. In this method, the raw material 10 is previously separated into a coarse-grain material and a fine-grain material by a bar screen 18 furnished above the downstream part 13B of the chute 13, and then the raw material 10 is transferred on the bar screen 15 and finally screened.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to powders having different particle sizes.
The present invention relates to a method and an apparatus for sieving powders / granulates that can effectively classify the granules by a combination of an approach chute and a bar screen.

[0002]

2. Description of the Related Art Conventionally, in order to improve the air permeability and combustion efficiency of a sintering raw material layer in a sintering machine, the sintering raw material is coarse grained material and fine grained raw material before the sintering raw material is charged into the sintering machine. A slit chute type classification device composed of a combination of an approach chute and a bar screen is used for sieving into and, and as a specific example thereof, a slit chute type classification device disclosed in JP-A-1-104725 is disclosed. There is a device. FIG. 6 conceptually shows the configuration of the slit chute type classifying device C. As shown in the figure, the slit chute type classifying device C includes an approach chute 100 arranged in an inclined state below a hopper (not shown), and the approach chute 100.
And a bar screen 102 composed of a plurality of linear members 101.
Also, below the bar screen 102 is a pallet 103.
Are arranged so that they can run freely. In addition, in the above-described configuration, the interval between the linear members 101 is set to gradually widen downward. The classification work (screening work) by the slit chute type classifying device C having such a configuration will be briefly described with reference to FIG. The sintering material a dropped and supplied from the hopper onto the approaching chute 100 via the feeder slides down on the approaching chute 100. On the extension line of the run-up chute 100, a bar screen 102, in which a plurality of linear members 101 having the same diameter are tensioned in the width direction, is provided.
Next, the upper surface of the bar screen 102 is slid down, first, the fine raw material b in the sintering raw material a is classified and dropped on the upper end 104 side, and the fine grain raw material c is slid down toward the lower end 105 side. It will be dropped one after another. On the other hand, the remaining coarse-grain raw material d that has slid down on the bar screen 102 without passing through the bar screen 102 is
As it is, it will fall from the lower end portion 105 of the bar screen 102. Then, of the sintering raw materials a classified in this way, the coarse-grain raw material d is first charged into the lower layer portion 106 of the traveling pallet 103, and then the intermediate layer portion 1
From 07 to the uppermost part 108, the fine grain raw material c and the fine raw material b are sequentially and continuously charged, and the sintering raw material layer 109 is formed in the pallet 103.

[0003]

However, the sieving work or the classification work by the above-mentioned slit type classifying device C still has the following problems. That is, the classification efficiency could not be sufficiently improved only by combining the run-up chute 100 and the bar screen 102. Specifically, in the actual sieving work, as shown in FIG. 7, the sintering raw material a that slides in layers on the single smooth sliding surface 110 of the run-up chute 100 causes vertical grain size segregation. Therefore, the sintering raw material a is
In the state where the segregation is small, it is transferred onto the bar screen 102 and sieved. Therefore, the coarse grain raw material d was mixed in the sintering raw material under the sieve, and the sieving efficiency was poor. It is possible to increase the length of the bar screen 102 in order to increase the classification efficiency, but in this case, the slit chute type classifying device C becomes large, and a large installation space and equipment cost are required. become. The present invention has been made in view of such circumstances, and can significantly improve the sieving efficiency or classification efficiency of all kinds of powders and granules including the above-mentioned sintering raw material, and has a compact structure. However, it is an object of the present invention to provide a sieving method and apparatus for powder / granular material, which can minimize the installation space to effectively utilize the space and can reduce the equipment cost.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
The method of sieving the powder / granular material described above, the raw material consisting of the powder / granular material dropped and supplied onto the running chute is passed through the gap of the main sieving bar screen provided on the downward extension line of the running chute. , Powder that is screened into fine-grain raw material and coarse-grain raw material
In the method of sieving a granular material, the raw material is pre-screened by segregating it into a fine-grain raw material and a coarse-grain raw material through a pre-screening bar screen arranged on the downstream side portion of the running chute. After that, the raw material is transferred onto the main sieving bar screen for main sieving. 3. The powder / granular material sieving apparatus according to claim 2, wherein the main screen comprises a run-up chute arranged in an inclined state in the lower part of the hopper, and a plurality of linear members arranged on a downward extension line of the run-up chute. Powder with a separating bar screen
In the granular material sieving device, the run-up chute is formed from an upstream side portion and a downstream side portion, a predetermined step is provided between both portions, and above the downstream side portion, the upstream side portion and the surface are provided. A pre-screening bar screen composed of a plurality of linear members is arranged in a single state.

[0005]

In the method and apparatus for sieving powder / granular material according to claims 1 and 2, when the raw material is dropped / supplied from the hopper to the upstream side portion of the running chute, the raw material slides on the upstream side portion of the running chute. Then, pre-sieving is performed in which the raw material is segregated into a fine-grain raw material and a coarse-grain raw material through a pre-screening bar screen. That is, by this preliminary sieving, the raw material flows on the downstream side portion of the run-up chute with the coarse-grained raw material segregated in the upper layer portion and the fine-grained raw material segregated in the lower layer portion. After that, of the raw materials transferred from the run-up chute to the main sieving bar screen, the fine-grained raw material is preferentially sieved or classified, and the main sieving is performed.

[0006]

According to the sieving method and apparatus for powders and granules according to claims 1 and 2, when the raw material is dropped and supplied from the hopper to the upstream side portion of the run-up chute, the raw material drops on the upstream side portion of the run-up chute. The raw material transferred to the main sieving bar screen was made so that the raw material was slid through the prescreening bar screen to segregate it into fine-grained raw material and coarse-grained raw material. It is possible to preferentially sieve the fine-grain raw material in the inside, and to sieve the coarse-grain raw material, so that the sieving efficiency or the classification efficiency of the powder / granulate can be remarkably enhanced.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to the attached drawings, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention.

Here, FIG. 1 is an explanatory view of a conceptual overall configuration of a powder / granular material sieving apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory view of the sieving operation, and FIG. FIG. 4 is a graph showing the relationship between the length of the separating bar screen and the overall screening efficiency, FIG. 4 is a graph showing the relationship between the gap of the pre-screening bar screen and the overall screening efficiency, and FIG. 5 is for the preliminary screening. 3 is a graph showing the relationship between the tilt angle of the bar screen and the overall screen efficiency.

As shown in FIG. 1, a hopper 11 having a sintering raw material 10 as an example of the raw material filled therein has a raw material cutting feeder 12 at a lower portion thereof. The sieving apparatus A for powder / granular material according to the embodiment of the present invention is the hopper 1
1 and the basic structure thereof will be described. The run-up chute 13 is provided immediately below the hopper 11 in an inclined state, and the run-up chute 13 is arranged on a downward extension line of the run-up chute 13 and includes a plurality of lines. And a bar screen 15 for main sieving, which is formed of a strip-shaped member 14. Although not shown, a pallet is movably arranged below the main sieving bar screen 15. The detailed configuration of the powder / granular material sieving apparatus A having the above-described basic configuration will be described below.

In the powder / granular material sieving apparatus A according to the present embodiment having the above-mentioned basic structure, as shown in FIG. 1, the run-up chute 13 has an inclination angle φ of the main sieving bar screen 15. The upstream side portion 13A and the downstream side portion 13B having substantially the same inclination angle .theta.
A step portion 16 having a required step h is formed between 3A and 13B. Further, above the downstream side portion 13B of the approach chute 13, a pre-screening bar screen 18 including a plurality of linear members 17 is arranged at parallel intervals. This pre-screening bar screen 18
Is arranged on an extension of the upstream portion 13A of the approach chute 13 and has the same inclination angle θ as that of the approach chute 13.
Having.

Next, the sieving operation or the classification operation of the sintering raw material 10 by the sieving apparatus A for the powder / granular material having the above-described structure will be described with reference to FIGS. 1 and 2.
In FIG. 1, when the raw material cutting feeder 12 is operated, the sintering raw material 10 is dropped / supplied from the hopper 11 onto the running chute 13, and the sintering raw material 10 is positioned on the sliding surface 13 a of the running chute 13 downward. It slides toward the main sieving bar screen 15.

By the way, as described above with reference to FIG. 1, the run-up chute 13 is composed of the upstream side portion 13A and the downstream side portion 13B in which the step portions 16 having the step h in a stepwise manner are provided and arranged. At the same time, a pre-screening bar screen 18 that is flush with the upstream portion 13A is provided above the downstream portion 13B. Therefore, as shown in FIG.
The sintering raw material 10 is dropped and supplied onto the upstream portion 13A of the. After that, the sintering raw material 10 is the upstream side portion 1
It slides on the sliding surface 13a of 3A and is transferred onto the pre-screening bar screen 18. At this time, since the pre-screening bar screen 18 is composed of a plurality of linear members 17 that are tensioned in the width direction, as shown in FIG.
When the sinter raw material 10 that slopes down slides down the upper surface of the pre-screening bar screen 18, first, the fine-grain raw material 10b in the sinter raw material 10 runs through the gap 18a of the pre-screening bar screen 18. Downstream portion 13B of the chute 13
Of the coarse grain raw material 10a that has been classified and dropped onto the upper end of the pre-screening bar screen 18 and has not passed through the gap 18a of the pre-screening bar screen 18 and has slid down on the pre-screening bar screen 18 as it is. Downstream part 1 of 13
3B is dropped to the lower end portion, and on the running surface 13a of the downstream side portion 13B of the run-up chute 13, the coarse-grain raw material 10a is segregated in the upper layer portion, and the fine-grain raw material 10b is segregated in the lower layer portion. It will flow.

Thus, the main sieving bar screen 1
On the approaching chute 13 immediately before 5, that is, on the downstream side portion 13B of the approaching chute 13, the coarse grain raw material 10a is in the upper layer portion,
Since the fine-grain raw material 10b flows in a state in which it is substantially completely segregated in the lower layer and pre-sieving is performed, the sintering raw material 10 transferred to the main sieving bar screen 15 in the subsequent main sieving is , The fine-grain raw material 10b is preferentially sieved or classified through the gaps 15a between the linear members 14,
The fine grain raw material 10b flows into a pallet (not shown) to form an upper layer portion of the sintering raw material layer. On the other hand, the coarse grain raw material 10a slides on the main sieving bar screen 15,
It flows into a pallet (not shown) to form a lower layer portion of the sintering raw material layer.

As described above, according to the embodiment of the present invention,
13A upstream of the approach chute 13 from the hopper 11
When the sintering raw material 10 is dropped and supplied to the above, the sintering raw material 10 slides on the upstream side portion 13A to pass the sintering raw material 10 through the gap 18a of the pre-screening bar screen 18 and the fine-grain raw material 10a and the coarse-grain raw material 10b. Since the pre-sieving that segregates into the powder is performed, the fine-grain raw material 10b in the sintering raw material 10 transferred to the main sieving bar screen 15 is preferentially sieved in the subsequent main sieving. In addition to lowering, the coarse grain raw material 10a can be sieved, and the sieving efficiency of powder / granular material,
Alternatively, the classification efficiency can be significantly increased. Further, the sintering raw material 10 is preliminarily changed to the coarse grain raw material 10a by the run-up chute 13.
Since it can be effectively segregated into the fine granule raw material 10b, it is not necessary to increase the length S of the main sieving bar screen 15, and the sieving apparatus A for powder / granulate can have a compact structure. Since it can be installed in the minimum installation space, it is possible to effectively use the space of a factory or the like and to manufacture at low cost.

Next, an experiment was conducted on the relationship between the length L of the pre-screening bar screen 18 used in the present embodiment and the total screen efficiency, and the results are shown in FIG. As is apparent from FIG. 3, when the length L of the pre-screening bar screen 18 is less than 1 m, the total screening efficiency is low, and when it is longer than 4 m, the powder / particulate screening device A is compact. The object of the present invention, which is to be achieved, cannot be achieved. Therefore, it is understood that the length L of the pre-screening bar screen 18 is preferably 1 m to 4 m.
Further, an experiment was conducted on the relationship between the distance δ of the gap 18a of the pre-screening bar screen 18 used in the present embodiment and the overall screen efficiency, and the result is shown in FIG. As is clear from FIG. 4, when the distance δ of the gap 18a of the pre-screening bar screen 18 is less than 20 mm, the overall sieve efficiency is low, and when it is greater than 40 mm, the overall sieve efficiency is similarly reduced. Therefore, the distance δ of the gap 18a of the pre-screening bar screen 18 is 20 mm to 40 mm.
It is preferred that Further, an experiment was conducted on the relationship between the inclination angle θ of the pre-screening bar screen 18 used in the present embodiment and the overall screen efficiency, and the results are shown in FIG. As is clear from FIG. 5, the overall screen efficiency is highest when the inclination angle θ of the pre-screening bar screen 18 is in the range of 40 ° to 56 °, and the overall screen efficiency is gradually increased as it becomes smaller than 40 °. The total screen efficiency of the screen gradually decreases as it becomes lower and becomes larger than 56 °.
The inclination angle θ is 40 °, which is the angle of repose of the fine grain raw material 10b
It turns out that it is preferable to set it to 56 °. Furthermore, the applicant of the present invention has proposed a conventional powder / granular material sieving apparatus in which the pre-screening bar screen 18 is not provided on the run-up chute 13 and the above-described powder / granular material sieving apparatus according to the present embodiment. A comparative experiment on the sieving efficiency was conducted for A, and the experimental conditions and results are shown in Table 1.

[0016]

[Table 1]

As is clear from Table 1, the powder / granular material sieving apparatus A according to the present embodiment has an overall sieve efficiency of 10% as compared with the conventional powder / granular material sieving apparatus. It turns out that it can be increased.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating the overall configuration of a powder / granular material sieving apparatus according to an embodiment of the present invention.

FIG. 2 is an illustration showing a state of the same sieving operation.

FIG. 3 is a graph showing the relationship between pre-screening bar screen length and overall screen efficiency.

FIG. 4 is a graph showing the relationship between the clearance distance of a pre-screening bar screen and the overall screen efficiency.

FIG. 5 is a graph showing the relationship between the tilt angle of the pre-screening bar screen and the overall screen efficiency.

FIG. 6 is an explanatory view of a conceptual overall configuration of a powder / granular material sieving apparatus according to a conventional example.

FIG. 7 is an explanatory diagram of a sieving operation of the device.

[Explanation of symbols]

A Powder / Granular Sieving Equipment 10 Sintering Raw Material 10a Coarse Grain Raw Material 10b Fine Grain Raw Material 11 Hopper 12 Raw Material Cutting Feeder 13 Running Chute 13a Sliding Surface 13A Upstream Part 13B Downstream Part 14 Linear Member 15 Main Screening Bar screen 15a gap 16 step part 17 linear member 18 prescreening bar screen 18a gap

(72) Inventor Junichiro Ikenaga 1-1, Tobata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture Inside Nippon Steel Co., Ltd., Yawata Works (72) Mitsuo Nishimata, Inaba, Tobata-ku, Kitakyushu, Fukuoka No. 1 inside Nippon Steel Co., Ltd. Yawata Works

Claims (2)

[Claims] 1. A fine-grained raw material and coarse particles are fed through a gap of a main sieving bar screen provided on a downward extension line of the run-up chute for feeding a raw material consisting of powder and granules dropped and fed onto the run-up chute. In the method of sieving a powder / granulate for sieving into a raw material, the raw material is divided into a fine-grain raw material and a coarse-grain raw material through a pre-screening bar screen arranged on the downstream side portion of the running chute. A method for sieving powder or granules, characterized in that segregation is performed for preliminary sieving, and then the raw material is transferred onto the main sieving bar screen for main sieving. 2. A powder comprising a run-up chute arranged in an inclined state at a lower portion of a hopper and a main sieving bar screen composed of a plurality of linear members arranged on a downward extension line of the run-up chute. In a granular material sieving device, the run-up chute is formed from an upstream side portion and a downstream side portion, a predetermined step is provided between both portions, and above the downstream side portion, the upstream side portion and a surface are provided. An apparatus for sieving powder or granules, characterized in that a bar screen for pre-sieving comprising a plurality of linear members is arranged in one state.