JPS62266185A - Method and device for sorting powder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for classifying powder and an apparatus therefor.

[Conventional technology] Conventionally, wind-powered classifiers have introduced a method in which primary air is used to disperse powder in an airflow and introduced into the classification section, and secondary air is introduced separately to create an airflow that contributes to classification. is common.

Conventionally, most methods have been to directly introduce powder into the primary air stream, and the amount of primary air is too large for the powder, resulting in reduced classification accuracy and difficulty in controlling the classification point. It had some problems. Additionally, since the overall air volume increases, it is necessary to use a relatively large blower.

In recent years, a method has been used in which the supply means is controlled at a high pressure of 0.5 to 2 kg/cm2 to blow high-pressure gas and powder into the classification chamber, and in this case, the amount of secondary air is equal to the amount of primary air. Although it may be possible to obtain good accuracy in the fine powder range, the feeding device must be in a pressure vessel, making it difficult to feed the powder, and the device is also large and expensive to operate. It has become a thing. That is, since high-pressure air is directly used as the primary air, there are problems such as extremely high running costs. moreover,
Due to the high pressure, flushing of the powder is likely to occur in the supply system, and because the differential pressure during blowing is large, the acceleration of coarse particles is particularly large, leading to problems such as poor classification accuracy in the coarse powder area (204 m or more -1-). It had a point.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method for classifying powder and an apparatus therefor that solve the problems described in -1- above.

An object of the present invention is to provide a method and apparatus for classifying powder by supplying the powder to a classifying means in a system open to atmospheric pressure.

An object of the present invention is to provide a powder classification force V and an apparatus that can obtain good powder dispersion with a relatively small amount of primary air compared to the amount of powder.

[1] The present invention has good classification accuracy and control of the classification point]
- To provide a classification force V that is easy to roll and a classification device.

[Means and Effects for Solving the Problems 1] According to the present invention, in a method for supplying powder from a container holding powder to a classifying means and classifying the powder, the powder is transferred from the container to the air injection means. is supplied via a powder supply means for quantitatively supplying the powder, the supplied powder is dispersed by the air injection means and is conveyed to the powder collection means, and the conveyed powder is There is provided a method for classifying powder, characterized in that the powder is classified by supplying it together with a pressurized gas whose pressure has been regulated via a powder collecting means to a powder classifying means.

Furthermore, a container for holding the powder, a powder supply means for quantitatively supplying the powder from the container, an air injection means for dispersing and conveying the supplied powder, Powder collecting means for collecting the transported powder and supplying the powder to the classification stage together with pressurized gas whose pressure is regulated, and There is provided a powder classification apparatus characterized by having a classification means for classifying the powder.

The present invention will be explained using FIG. 1 corresponding to an embodiment.

FIG. 1 is a flowchart 1 schematically showing an embodiment of a classification method and a classification apparatus for carrying out the present invention.

This classification device is a cyclone equipped with a vibrator as a powder supply device connected to an Elpau Jet classifier (manufactured by Nissen Mining Co., Ltd.). Pipe 3, raw material input conduit 4, powder collection means 5, injection means 7, piping 6 connecting powder collection means 5 and injection means 7, vibrating feeder 8, powder supply means 9, powder collection means. Exhaust pipe 10, air volume control valve 11, air speed meter 12, classified product discharge pipe 13, classified product collection means 14, classifier air volume control i-roll valve 15, blower 16, classifier [
1 tightening means 17 and a pressure gauge 18.

Raw powder:] is supplied from the powder supply means 9, smoothed by the vibration feeder 8, and then transferred to the injection means 7.
It is mixed with air and dispersed well, and the pipe 6
The powder is guided to the powder collecting means 5 through the. A part of the air sent to the powder and seven powder collecting stages 5 is discharged from the bottom of the powder collecting means 5, and is sent to the classifier l via the raw material input conduit 4. At this time, the powder collecting means 5 is operated by the air volume control valve 1.
1 and the tightening means 17 at the entrance of the classification chamber to reduce the static pressure to O~+.
3,000 mmaq, preferably +100 to +1,
Controlled to a positive pressure of 500 mmaq (higher than atmospheric pressure), the negative pressure inside the classification chamber (lower than atmospheric pressure) is significantly increased, and the powder and air are removed without putting a burden on the blower 18. be sent. In order to control the ratio of primary air supplied to the classifier and powder to a mixing ratio with good fluidity and good dispersion and send it to the separation chamber 1, the volume ratio of air:powder is 1: 0.01~1:
It is preferable to control it to 0.0003, thereby obtaining good classification performance. In addition, in a method of introducing powder into primary air such as a conventional fixed wall classifier or rotary classifier, this ratio is usually 1:0.
It is operated under conditions with a low powder concentration of 0002 or less.

As described in -1-, the powder is sent to the classification chamber together with pressure-regulated primary air and classified.

In the classification method of the present invention, the powder is transported by the injection means, and the powder supply side is 10 to 3000 +++
It can be supplied by applying a positive pressure of maq, and the mixing ratio of powder can be controlled by injection, and the powder can be well dispersed in the air, and can be supplied smoothly without pulsation, so it has good results in both coarse and fine powder areas. Classification accuracy can be obtained. In addition, unlike suction feed, the present invention does not require an increase in air volume or static pressure, and unlike high-pressure feed, there is no need to use compressed air as primary air, so energy consumption can be reduced. It is possible. Particularly, in classifying powders that are difficult to disperse such as toner powder and fine powders of 3 to 5 μm or less, a large effect in terms of energy saving can be obtained. In addition, since the device can be injected without causing flushing by controlling the injection means even when the device is open to the atmosphere, under positive pressure, or under negative pressure, the device is easier to operate, and connections with previous and previous processes are easier than before. .

The flow meter 12 and pressure gauge 18 shown in the flowchart of FIG. 1 are used as means for detecting the amount of exhaust air and the internal pressure of the powder collecting means 5, respectively, and by having these, the operating conditions can be adjusted. Easier to control.

Examples of the powder supply means 9 include quantitative supply means such as a Flotron manufactured by Kaiyō Micron, an auto feeder manufactured by Konken, and a screw feeder.

The vibrating feeder 8 is useful for smoothing out pulsation and obtaining a smooth flow of powder.

The powder collecting means 5 may be any of a cyclone, a pre-cyclone type bag filter, a bubble filter, etc., but a cyclone equipped with a vibrator is particularly preferred since the collected powder is continuously supplied.

As the injection means 7, various types can be used in addition to an air injection feeder as shown in FIG. Alternatively, an injection means using a high-pressure blower may be used.

The flow rate at the tightening means 17 at the inlet of the classifier is 3 to 100 II/
Very good results are obtained at speeds of 15 to 70 m/s.

The classifier is Elpaujet classifier manufactured by Nissen Mining Co., Ltd.
It can be connected to various classifiers such as Nippon Pneumatic Kogyo's DS separator and Kaiyo Micron's MS separator. With classifiers that use a large amount of primary air other than Elpau Jet classifiers that have a small amount of primary air, it is possible to reduce this amount of primary air, which also makes it possible to improve classification accuracy and save energy. At the same time, it becomes possible to lower the classification point to an even smaller particle size.

FIG. 2 shows an example of conventional high-pressure feeding, in which a powder supply means 9 is placed in a box 21 pressurized by 0.5 to 2 atm above atmospheric pressure.
, contains a vibrating feeder 8, etc., and supplies high-pressure air from an air pipe 19 to the powder supply means 9 and the opening 2 of the vibrating feeder 8.
It is configured to feed from 0. The apparatus shown in FIG. 2 requires a large amount of pressurized air to maintain the box 21 at high pressure.

FIG. 3 shows a specific example of an injection feeder applicable to the classification method and classification apparatus of the present invention, and includes an air nozzle 25, a guide nozzle 27, a powder and air suction port 24, and an air nozzle fixing guide 28. and a casing 23.

[Example] The performance of the classification device of the present invention shown in FIG. 1 and the conventional device shown in FIG. 2 was compared. The volume average particle size of approximately 10.1μ11 (contains approximately 7% by number of fine powder with a particle size of 2 or less) measured with a coulter counter was classified at 15 kg/hour to obtain a volume average particle size of approximately 11.0 #L. (containing 2% or less of fine powder with a particle size of 2IL11 or less), the yield was 80% in the apparatus of the present invention, while it was 75% in the apparatus shown in FIG. Furthermore, the amount of air in the air injection compressor used to introduce the raw material into the classification fit is 0.05 ra3 in the present invention.
In contrast, the high-pressure feed system shown in FIG. 2 requires 0.3 m3/min, resulting in a significant difference in the cost of rolling the equipment. This tendency became even stronger as the volume average of the classified products became smaller.

[Effects of the Invention] As described above, according to the present invention, good dispersion of powder can be obtained with a relatively small amount of primary air activation, and good classification accuracy and easy classification can be achieved. This makes it possible to control points and save energy.

[Brief explanation of drawings]

FIG. 1 shows a flowchart showing the classification method and classification apparatus of the present invention, which is equipped with an Elpau jet and a cyclone, and FIG. 2 is a flowchart showing a pressurized supply type classification method that does not have a cyclone. and the third
The figure is a sectional view schematically showing an air injection feeder applicable to the present invention. ■...Classifier main body 2...Secondary air control valve 3...Secondary air introduction pipe 4...Raw material input conduit 5...Powder collection means 6.
... Piping 7 ... Injection means 8 ... Vibration feeder 9 ... Powder supply means 10
...Exhaust pipe 11...Air volume control valve 12...Air acid meter 13...Classified product discharge pipe 14...Classified product collection means 15...Air volume control valve 16...Blower 17... Tightening means 18... Pressure gauge 18... Air piping 20... Open [1
Part 21...Box 23...Casing
24... Suction port 25... Air nozzle 26... Air nozzle fixing guide 27... Guide nozzle Fig. 1 1 B Fig. 2

Claims (2)

[Claims] (1) In a method for classifying powder by supplying the powder from a container holding the powder to a classifying means, the powder is supplied from the container to the air injection means via a powder supply means for quantitatively supplying the powder to the air injection means. The supplied powder is dispersed by the air injection means and conveyed to the powder collection means, and the conveyed powder is pressurized via the powder collection means. A method for classifying powder, characterized in that the powder is classified by supplying the powder together with a gas to a powder classification means. (2) A container for holding the powder, a powder supply means for quantitatively supplying the powder from the container, an air injection means for dispersing and transporting the supplied powder, and a transporter. a powder collecting means for collecting the powder and supplying the powder to the classification means together with the pressure-regulated pressurized gas; and a powder collecting means for collecting the powder supplied from the powder collecting means. A powder classification device characterized by having a classification means for classification.