JPS62204866A - Grinding and classifying apparatus - 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] [Technical field to which the invention pertains]

This invention is a pulverizing and classifying device that combines a pulverizer and an air classifier to continuously produce fine powder products by pulverizing raw materials supplied into the system with the pulverizer and then classifying them with the air classifier. Regarding the configuration of

[Prior art and its problems]

For example, scaly graphite powder is used in a wide variety of applications, including pencil lead, paint, and lubricants. By the way, as a method for producing this type of fine flaky graphite powder, a crushing and classifying apparatus that combines a jet mill and an air classifier has been known. Here, the apparatus will be explained with reference to FIG. 4. In the figure, 1 is a jet mill, 2 is an air classifier, 3 is, for example, a screw type feeder for supplying raw materials, and 4 is a cyclone. Reference numeral 5 designates a bag filter, in which the scaly graphite raw material 6 supplied from the feeder 3 to the raw material supply port 3a is air-transported within the pipe by a compressed air flow (described later), enters the pneumatic classifier 62, and passes through it. and introduced into the jet mill 1. Here, the raw material as the crushing material is air pressure kllll17. The crushed material particles are taken into the supersonic jet stream ejected into the jet mill 1 through the air dryer 8, and are finely pulverized by collisions between particles of the crushed materials and collisions between the crushed materials and the collision plate. The crushed product is air conveyed from the outlet of the jet mill 1 to the inlet of the air classifier 1, and is classified into coarse powder and fine powder by the air classifier 2. Here, the fine powder is classified by airflow type 41si2
It enters the cyclone 4, where it is separated into solid and gas, and stored in the collection hopper 4a of the cyclone, from which it is taken out as a pulverized product. On the other hand, the coarse powder classified by the air classifier 2 is introduced from the bottom into the jet mill 1 together with the newly supplied raw material 6 from the crushed material supply feeder 3, and after being pulverized, it is returned to the air classifier 2. do. Note that the air discharged from the air classifier 2 and the cyclone 4 is purified by a bag filter 5 and then exhausted to the outside of the system through a blower 5a. However, the above-mentioned pulverizing and classifying apparatus employing a jet mill has the disadvantage of low energy efficiency. In other words, as mentioned above, a jet mill uses a supersonic jet stream, and its operation consumes a large amount of high-pressure air, so the air pressure required to obtain a pulverized product from raw materials is 1
The power consumption of one machine is large, resulting in high running costs.

[Purpose of the invention]

This invention was developed in consideration of the above points, and is more energy efficient than the above-mentioned pulverization and classification method using a jet mill.In addition to high pulverization efficiency, the raw material is It is an object of the present invention to provide a crushing and classifying device that can perform crushing and classifying processing by smoothly conveying crushed products with air current.

[Key points of the invention]

In order to achieve the above object, the present invention adopts a moving magnetic field type crusher as a crusher, and installs an air ejector for sucking out powder at the bottom outlet of the air classifier, and from the air ejector, the An air conveying pipe for feedback is installed between the magnetic field classifier and the inlet of the air classifier, and the outlet of the moving magnetic field crusher and the inlet of the air classifier are installed in the air conveying pipe. The route between the pulverizer and the pulverizer is equipped with a raw material supply inlet for the raw material feeder and an air inlet for intake of make-up air into the air classifier. While finely pulverizing the product, it is possible to smoothly supply raw materials into the system through air conveyance, provide coarse powder feedback from the air classifier to the pulverizer, and ensure the necessary air flow rate in the air classifier. Moreover, the amount of high-pressure air consumed for air conveying the raw material and coarse powder can be reduced to about L/10 compared to the amount of high-pressure air required for the conventional jet mill system, making it possible to significantly improve energy efficiency.

[Embodiments of the invention]

FIG. 1 is a system diagram of a crushing and classifying device according to an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing the principle configuration of the moving magnetic field type crusher in FIG. 1, and correspond to FIG. 4. Identical members are denoted by the same reference numerals.That is, according to the present invention, a moving magnetic field type pulverizer designated by reference numeral 9 is employed as the raw material pulverizer. Further, an air ejector 10 is installed on the bottom outlet side of the air classifier 2 to suck out and recover coarse powder and raw materials classified by the classifier, and from the air ejector 10 via the moving magnetic field type crusher 419. An air conveying pipe line 11 for feedback is installed between the air flow classifier 2 and the inlet of the air classifier 2. Further, between the outlet of the moving magnetic field type crusher 9 and the inlet of the airflow classifier W12, there is a raw material supply port 3a facing the raw material supply feeder 3 and an air flow to the airflow classifier 2 in the middle of the air conveying pipe 11. Air inlets 12 serving as replenishment intakes are opened in order. In addition, a powder level meter 13 is installed at the bottom of the airflow classifier 62 to detect the accumulated amount of coarse powder and raw materials classified in the machine, and based on the output signal of this powder level meter 13, the raw material supply The operation of the feeder 3 is controlled to appropriately control the supply amount of the raw material 6. On the other hand, the principle of the above-mentioned moving magnetic field type crusher 9 was developed in Japanese Patent Application Laid-open No. 58
-45754, and its configuration is the second
As shown in FIGS. 3 and 3, a moving magnetic field type crushing ff9 consists of a crushing container 91 made of non-magnetic material and a pair of linear motors placed above and below the processing container 91.
2.93, and inside the processing container 91 there are many spindle-shaped 0 made of ferromagnetic material in advance.
An operating body 94 is housed therein. Reference numerals 95 and 96 are an inlet for the crushed material and an outlet for the crushed material, which are opened on both end faces of the processing container, and a screen 97 for preventing the operating body 94 from escaping is provided on the exit side. By supplying power to the moving magnetic field generators 92 and 93 with such a configuration, moving magnetic fields φl and φ2 in opposite directions are generated,
A rotating magnetic field acts on the processing container 91 placed within the magnetic field of this moving magnetic field. As a result, the operating body 94 is
It levitates within the container due to the electromagnetic force based on the interaction with the moving magnetic field, and moves around along the moving magnetic field while rotating. By pneumatically transporting the crushed material P into the processing container 91 through the inlet 95, the crushed material P violently collides with the operating body 93 moving within the processing container and is finely pulverized. The crushed material is transported outward through the outlet 96 of the processing container 91. Next, returning to FIG. 1, the raw material pulverization and classification operation according to the illustrated embodiment will be explained. The raw material 6 supplied from the raw material supply feeder 3 to the raw material supply port 3a is air-filled by the negative pressure acting on the raw material supply port. It is injected into the conveyance path 11, merges with the crushed material air-transported from the moving magnetic field type crusher 9, and is sent to the airflow type classification 112. On the other hand, the coarse powder and raw materials that have been classified by the airflow classifier a2 and remain at the bottom of the machine are sucked out from the classifier by the air ejector 10 and sent to the moving magnetic field type crusher 9 by air conveyance. In this case, the air ejector 10 blows out high-pressure air compressed to about 5 to 6 kg/aj from the air compressor 7, and the raw material and coarse powder are sucked out from the classifier 2 side by the negative pressure generated in the ejector. and air conveys it toward a moving magnetic field type crusher 419. In addition, the required flow rate of the high-pressure air flow necessary for air conveyance at that time is approximately 1/1 compared to the conventional jet mill method shown in Figure 4.
10, and the power consumption of the air compressor that creates the high-pressure air flow is significantly reduced. Moreover, by selecting the amount of high-pressure air to be the minimum amount necessary for air transport of raw materials and coarse powder, sufficient residence time of the crushed materials inside the moving magnetic field type crusher 9 can be ensured, and the raw material and coarse powder can be It becomes possible to efficiently pulverize powder. On the other hand, the crushed product crushed by the moving magnetic field type crusher 9 and the raw material 6 supplied from the raw material supply feeder 3 are pneumatically conveyed in the air conveying pipe 11 to the air classifier 2. After being sent to the inlet, it is classified into coarse powder and fine powder, and the fine powder is carried out to the subsequent cyclone 4. In addition, in this process, classification using an air classifier requires a large amount of air, whereas air compression! i1
The flow rate of conveying air supplied into the system through 7 is relatively small, and this air volume alone is insufficient for the air flow rate required for the classification process. Since air is taken in and replenished into the system through the air inlet 12 that opens to the conveyance path 11, the pneumatic classification fi2 and the subsequent cyclone 4 can be operated stably without insufficient air flow. Powder level meter 1 at the bottom of machine 2
3 is installed, and the raw material supply feeder 3 is operated and controlled based on the output signal of this powder level meter to adjust the amount of raw material supplied. It is possible to maintain the body retention amount at a predetermined appropriate amount and continue operation with balance. According to experiments conducted by the inventor, when comparing the energy efficiency required to obtain a pulverized product by using scaly graphite with an average particle size of 60 μm as a raw material and pulverizing it to a particle size of 6 μm with a conventional jet mill method, IKg While the conventional method requires 2.2 KW of electricity to obtain a pulverized product, the method of the present invention requires less than half I KWH, confirming that energy efficiency can be significantly improved. [Effects of the Invention] As described above, according to the present invention, a moving magnetic field type crusher is used as the crusher, and an air ejector for sucking out powder is provided at the bottom outlet of the air classifier. An air conveying pipe for feedback is installed between the air ejector and the moving magnetic field classifier to the inlet of the air classifier, and a moving magnetic field crusher is installed in the air conveying pipe. The moving magnetic field type While utilizing the high pulverizing performance of the pulverizer, it is possible to smoothly supply raw materials into the system through air conveyance and feedback of coarse powder.Also, it is possible to secure the required air flow rate with an air classifier, and it is possible to It is possible to provide a crushing and classifying device that has high practical value and has significantly improved energy efficiency compared to a crushing and classifying device that uses a jet mill.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a crushing and classifying device according to an embodiment of the present invention, Fig. 2 is a principle configuration diagram of the moving magnetic field type crusher in Fig. 1, and Fig. 3 is a sectional view taken along arrow ■-m in Fig. 2. , FIG. 4 is a system diagram of a conventional jet mill type crushing and classification Vt device. In each figure, 2: air classifier, 3: raw material supply feeder, 3a: raw material supply port, 4: cyclone, 5:
Bag filter, 6: Raw material, 7: Air compressor, 9: Moving magnetic field crusher, 10: Air ejector, 11: Feedback air conveying pipe, 12: Air inlet, 13: Powder level meter. Figure 2 Figure 3

Claims (1)

[Claims] 1) A pulverizer and an air classifier are combined, and the raw material supplied into the system is pulverized by the pulverizer and classified into fine powder and coarse powder by the air classifier. In a crushing and classifying device in which the powder is fed back to the crusher, re-pulverized, and then sent to the air classifier again, a moving magnetic field type crusher is adopted as the crusher, and the bottom outlet of the air classifier is An air ejector for sucking out powder is installed, and an air conveying pipe line for feedback is installed between the air ejector and the moving magnetic field classifier to the inlet of the air flow classifier. A raw material supply port of a raw material supply feeder and an air inlet for intake of make-up air to the pneumatic classifier are provided in the path between the outlet of the moving magnetic field crusher and the inlet of the pneumatic classifier in the pipeline. A crushing and classifying device characterized by the following configuration. 2) In the pulverizing and classifying apparatus according to claim 1, a powder level meter is provided at the bottom of the air classifier, and a powder level meter is provided at the bottom of the air classifier, and the amount of coarse powder accumulated in the classifier is detected by the powder level meter. A crushing and classifying device characterized by appropriately controlling the amount of raw material supplied from a raw material supply feeder.