JPS62160174A - Apparatus for classifying particulate material - 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 an apparatus for classifying powder or granular materials using a gas flow.

(Prior art) There are many apparatuses for dispersing powder and granular materials in a gas flow and classifying them using centrifugal force, etc., as seen in, for example, Japanese Patent Publication No. 56-20912 and Japanese Patent Publication No. 59-51354. Suggestions have been made. However, in the case of such conventional equipment, when the powder or granular material to be classified tends to aggregate and contains aggregated coarse particles, it is difficult to classify particles with an average particle size of several μ or even less than μ. In such cases, there was a problem of poor classification accuracy and lack of reliability and stability.

That is, a large number of fine particles divided into several pieces were contained in the large particle collection section, and the classification efficiency and accuracy were insufficient.

As a result of research on this point, the present inventor found that by repeating the classification process several times, the agglomerated particles disappear.Furthermore, by installing a crusher in front of the classifier and classifying after passing through the crusher, the agglomerated particles can be eliminated. We found that the classification efficiency is good without any problems. However, adopting such a method complicates the process and increases equipment and operating costs, so it cannot be said to be advantageous for use as operational equipment. On the other hand, as a result of further studies on the above-mentioned classification process, it was found that although aggregated particles are classified as apparently large particles, they collide with walls etc. during classification and are divided into small or fine particles. It was found that it was mixed in coarse particles.

Based on this knowledge, the present invention was made by repeatedly conducting various tests, and it was discovered that the simplest and most efficient method is to collide powder and granules (agglomerated particles) with a jet of air, leading to the present invention. The purpose is to provide a device that has a simple structure, can completely crush or decompose aggregated particles, and can stably perform highly accurate classification.

This objective is achieved by the following configuration.

(Structure of the Invention) That is, the present invention is an apparatus for classifying cohesive powder or granules using a gas flow, in which the powder or granules are accelerated and ejected into an inlet pipe portion that allows the powder or granules to flow into the classifier body together with gas. This apparatus is characterized in that it is provided with a constriction section for evaporating the constriction, and a collision plate for the powder and granule is installed in front of the constriction section.

(Example) The present invention will be described below based on the drawings. FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, and FIG. 2 is an overall explanatory view.

In the figure, 1 is the main body of a classifier that uses centrifugal force; the upper part is the outlet pipe 2 for air, which is the working fluid, and the lower part is the outlet pipe 3.4 for the classified powder and granular material (this is when the classification range is further subdivided. , an outlet pipe is provided accordingly), and an air flow and an inlet pipe 5 for the powder or granular material, which is the coarse raw material, dispersed therein. Reference numeral 6 denotes an inflow conduit leading to the airflow generating means, and a supply pipe 7 for powder and granular material to be supplied via a constant supply means is attached to the upstream region, and the downstream end is connected to the introduction pipe 5.

Although the inflow conduit 6 is usually of a quadrilateral cross section, it may also be of a circular or other cross section. Reference numeral 8 denotes a means for crushing agglomerated powder and granular material provided in the inflow conduit 6, and a diaphragm 10 forming a diaphragm section 9 that accelerates and jets out air flow containing the granular material, and a diaphragm 10 immediately downstream of the diaphragm 10. It has a collision plate 17 provided corresponding to the front position of. The throttle body 10 is made of a rectangular plate-like or block-like body, and its lower end is inclined to reduce the cross section of the pipe toward the downstream side so as to smoothly accelerate the airflow, and has an edge at the lowest end that becomes the jet nozzle 11. 12 is formed. The aperture body 10 is a support nozzle 13
It is inserted into the flange 14 and attached to the flange 14 via an adjustment spacer 15. At the front of the jet nozzle 11, the pipe is bent approximately 90' downward to provide a wide free space 16 that does not restrict the jet air flow, and the inner wall of the pipe in front of the jet nozzle 11 is designed to prevent the jet air flow, especially the condensation therein. A collision plate 17 for spraying powder and granules is attached. The collision plate 17 may be mounted in a sliding manner so as to be easily replaceable, or the inner wall of the tube itself may be used as the collision plate in some cases.

In addition, the inflow conduit 6 corresponding to the side part of the throttle part 9 has a spout 1.
An opening 18 is provided that allows the area of the opening 1 to be easily confirmed and the clearance to be measured using a searcher or the like, and a transparent body made of glass or plastic is attached to this opening 18 to form a viewing window.

Incidentally, the spout 11 is adjusted by the spacer 15 so that the aperture body 10
The opening area can be changed arbitrarily by changing the height.

In such a device, the powder and granules transported by the gas flow are guided through the inflow conduit 6 to the flow restrictor 9, where they are accelerated by the gas flow, increase the speed from the jet port 11, and are ejected to the front position. The particles collide with the collision plate 17, and the aggregated particles are almost completely crushed by this collision. Next, the powder is rectified in the inflow conduit 6 and guided along with the air flow to the classifier main body 1, where it is classified into a predetermined particle size range. In this case, the classifier body 1
The powder and granules supplied to the granules are accelerated or ejected and collided with the collision plate 17, which is a crushing means provided immediately before, so that the agglomerated powder and granules are almost completely disintegrated by the shock. The particles are crushed and separated into individual particles, which are transported to the classifier main body 1 by an air flow. Therefore, highly accurate and stable classification is possible.

Here, the clearance (opening area) of the jet nozzle 11 is adjusted as appropriate by moving the throttle body 10 up and down according to the degree of agglomeration of the powder, and furthermore, the air flow rate, the amount of powder supplied, etc. are adjusted appropriately. By setting it at a certain value, it becomes possible to perform the best crushing and classification.

Table 1 shows the classification results of the apparatus according to the present invention shown in FIGS. 1 and 2 and the conventional apparatus shown in FIGS.

In this case, kaolin was used as the powder and air was used as the gas flow, and the other conditions were the same (however, in the device of the present invention, the air pressure was increased by the pressure loss due to the constriction part, and the flow rate at the inlet of the classifier body was approximately equal). .

Table 1 The amount of particles larger than 2μ is shown in weight percent, and this value suggests a broadening of the particle size distribution around the average particle size of the particles. That is, as the zero value becomes smaller, the distribution around the average particle size becomes sharper.

As is clear from the above results, by installing the crushing means immediately in front of the classifier main body, the aggregated coarse particles are crushed and the average particle size is reduced, but the amount of particles of 2μ or more is significantly reduced, and It can be seen that fine powder with a sharp particle size distribution can be obtained in high yield.

(Effects of the Invention) As described above, according to the present invention, the amount of aggregated particles can be easily and easily reduced by a simple device before the mixed flow of powder and granular material and gaseous fluid flows into the classifier body. It is possible to perform high-precision classification with just one classification and is extremely effective since it does not affect the classification process.

Furthermore, it can be easily and easily improved by modifying the piping section, which is very advantageous in terms of equipment costs.

[Brief explanation of drawings]

FIGS. 1 and 2 are an enlarged view of essential parts and an overall explanatory view showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Classifier main body, 6... Inflow conduit, 8... Crushing means, 9... Throttle part, 10... Throttle body, 11... spout, 17... collision plate.

Claims (1)

[Claims] In an apparatus for classifying cohesive powder and granular materials using a gas flow, a constriction part for accelerating and ejecting the powder and granule material is provided in the introduction pipe portion that causes the powder and granule material to flow into the classifier body together with gas, and the constriction part A granular material classification device characterized by having a granular material collision plate installed on the front side.