JPH0440292B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glass beads having improved particle size uniformity, excellent sphericity, and excellent fracture resistance and abrasion resistance.

BACKGROUND ART Conventionally, there has been known a method for producing glass beads in which glass powder is heated and spheroidized together with a release material such as carbon in a rotary tilting furnace.

However, this technique requires complicated steps such as crushing and classifying the molten glass, and also requires a large amount of thermal energy. Moreover, the particle size distribution of the obtained beads is dominated by the yield in the crushing and classification steps and has the disadvantage of being broad. In addition, since the crushed particles having a complicated uneven shape are softened and made spherical, they tend to fold inside together with the mold release material, which tends to result in poor fracture resistance and wear resistance.

Therefore, when the beads obtained in this way are used as a dispersion medium in the dispersion and homogenization process of raw materials in various industrial fields, a part of the bead material is likely to be mixed into the raw materials as impurities and change the quality of the raw materials. Furthermore, with this technique, it is difficult to produce beads with a small particle size of 1 mm or less.

Furthermore, various techniques are known for producing beads by directly cutting molten glass into pieces.

For example, the flowing molten glass can be blown away with high-temperature, high-speed combustion gas, or the centrifugal force of a rotating body such as a disk or blade can be used to make a thin film and scatter it.
Alternatively, the particles are continuously flicked from the side with a chopper wheel to break them into pieces. In these technologies, a glass flow with an extremely low viscosity of 10 to 15 poise or less under suitable conditions is subjected to different mechanical stimuli to form particles, which are then shaped into spherical particles using their surface tension. It is. However, in both cases, the fragmentation of the glass flow is carried out randomly in an open space, without any restrictions, and is left to the free movement of the low-viscosity glass.

Therefore, with these techniques, it is difficult to produce beads with a sharp particle size distribution, and it is difficult to produce beads with a sharp particle size distribution.
It is difficult to obtain beads with a large particle size of mm or more. Furthermore, the low-viscosity, high-temperature glass mentioned above becomes heterogeneous due to contamination due to erosion of materials such as furnaces and conduits, resulting in uneven particle sizes and sphericity of the resulting beads, as well as fracture and abrasion resistance. gender becomes susceptible to deterioration. Therefore, in order to avoid this problem, if the glass flow is made to have a low temperature and high viscosity, fragmentation and spheroidization will be incomplete, producing irregularly shaped beads with tail threads, and the manufacturing yield will tend to decrease rapidly.

The purpose of the present invention is to comprehensively eliminate the drawbacks of the conventional glass bead production techniques, to improve the uniformity of particle size, to have excellent sphericity, and to have excellent fracture resistance and abrasion resistance. The object of the present invention is to provide a method for efficiently producing glass beads having a diameter of 0.5 mm or more using simple means.

In view of the above-mentioned actual conditions observed in conventional glass bead manufacturing techniques, the present inventor has conducted various tests and research, and has found that a high viscosity glass flow of 10 ² to ^{10 3.5} poise, which is considered incompatible with conventional glass bead manufacturing techniques, has been developed. We have discovered that the above objectives can be achieved by adopting a new method of cutting using a fixed blade and a movable blade that slides and passes under the fixed blade. .

The method for manufacturing glass beads according to the present invention is characterized in that a molten glass stream with a viscosity of 10 ² to 10 ^3.5 poise is continuously freely flowing down, and a fixed blade is provided close to the glass stream, and the lower surface of the fixed blade is The molten glass particles are continuously obtained by cutting with a moving blade that passes while sliding. In the present invention, the reason for determining the viscosity range of the glass flow as described above is that if the viscosity is less than 10 ² poise, the cut glass particles will easily break into pieces due to the impact during cutting, and if it exceeds 10 ^3.5 poise, the cutting blade will be damaged. This is because it is more likely to occur.

Next, an embodiment of the method for manufacturing glass beads according to the present invention will be described with reference to the drawings.

That is, FIG. 1 shows the process of cutting a glass stream 3 continuously flowing out from a conduit 2 attached to a glass melting furnace 1 to form particles 4, and spheroidizing them in the air to produce beads 4'. FIG. 2 is a partial plan view showing the glass flow cutting process in FIG. 1, and FIG. 3 is a partial plan view showing the glass flow cutting process in FIG.
It is an enlarged cross-sectional view of the A′ line side. In the melting furnace 1, soda lime glass is melted. glass style 3
is vertically freely flowing down from the conduit 2 at a constant flow rate of 10 kg/hour while maintaining a constant viscosity of 10 ^2.5 poise by a known glass flow rate control means (not shown). A rod-shaped fixed blade 5 having a recessed portion is provided horizontally adjacent to the side surface of the glass flow 3. The fixed blade 5 has a double-tube structure in which cooling fluid can be circulated to prevent overheating and fusion caused by the glass flow. Further, at the lower part of the fixed blade 5, there is provided a ring 7 coaxially and horizontally attached to the rotating shaft 6, and a total of 16 rotationally movable blades 8 fixedly installed at equal intervals around the ring 7. The movable blade 8 is placed at a position where it can cut the glass flow 3 with its tip, has a rotation radius of 25 cm, and can be appropriately cooled by a water droplet spray nozzle 9. The upper surface of the movable blade 8 can slide over the lower surface of the fixed blade 5 one after another, and the ring 7 guides the movable blade 8 to safely accomplish this passage.

Therefore, using the above device, we moved the movable blade 8 to 1650R/
When rotated at a constant speed M, the glass flow 3 is continuously cut between the fixed blade 5 and the tip of the movable blade 8 without any trouble, resulting in particles 4 with extremely uniform grains.
I was able to do this. Cut glass particles 4
The particles immediately separated from the tip of the moving blade, became spherical in the air due to surface tension, solidified, and were collected in the collection box 10. At this time, since the glass flow 3 had the above-mentioned appropriate viscosity, it did not randomly break into small pieces due to the impact of cutting, and did not cause folds or tail threads. Thus, the particle size range is 1.6±
Beads with a diameter of 0.2 mm and excellent sphericity could be easily obtained. Figure 4 is an example showing the difference in particle size distribution depending on the manufacturing method of the same kind of glass beads. This is due to From the figure, it can be seen that the method according to this example has a remarkable effect of making the particle size uniform compared to the conventional method.

In this example, the particle size could be arbitrarily selected within the range of 0.5 to 5 mm by appropriately changing the flow rate and viscosity of the glass flow and the number and speed of the moving blades. In addition, since the glass flow is at a relatively low temperature, there is less erosion of the furnace material, etc., and the shape of the conduit is difficult to change, so the beads obtained are not only better in shape than the conventional method, but also have better fracture resistance and The wear resistance is also much better.

When carrying out the method of the present invention, the method of using fixed blades and movable blades, the type of glass, etc. is not limited to the above embodiments, and appropriate additions and changes may be made without departing from the spirit of the present invention. . For example, regarding the usage of a fixed blade, the glass flow cutting part has a single tube structure using a porous metal member,
Heated gas is injected from inside to form a gas film between the glass stream and the fixed blade to maintain a non-contact state, reducing the cooling effect of the fixed blade on the glass stream and promoting spheroidization of cut pieces. You may also do so. Alternatively, the fixed blade may be cylindrical, the inner peripheral surface thereof may be placed at a fixed position close to the glass flow, and the fixed blade may be rotated horizontally at low speed. The movable blade may be moved in a straight line instead of rotationally. Furthermore, known heating means may be added to spheroidize the cut grain pieces. The type of glass is not limited to the above-mentioned examples, and it is also possible to use known impact-resistant and wear-resistant glasses to produce beads with even better mechanical strength characteristics as well as shape accuracy.

As described above, the method for manufacturing glass beads of the present invention involves passing a glass flow having a viscosity of 10 ² to ^{10 3.5} poise while sliding between a fixed blade provided close to the glass flow and the lower surface of the fixed blade. Since the bead is cut using a moving blade, the uniformity of the bead particle size is much better than that of conventional methods, the sphericity is good, and the fracture resistance and abrasion resistance are also improved. Therefore, the improvement effect is extremely large and is industrially useful.

[Brief explanation of drawings]

FIG. 1 is a side view showing one embodiment of the present invention. Figure 2 is a partial plan view of the glass flow cutting process in Figure 1, and Figure 3 is A-2 in Figure 2.
It is an enlarged cross-sectional view of the A′ line side. FIG. 4 is a comparison diagram of particle size distribution of beads according to an example of the present invention and a conventional method. In the figure, 3...Glass flow, 4...Glass particles, 5
...Fixed blade, 8...Movable blade.

Claims (1)

[Claims] 1. A molten glass stream of 10 ² to ^{10 3.5} poise, which is continuously freely flowing down, is cut by a fixed blade placed close to this glass stream and a movable blade that passes while sliding on the lower surface of this fixed blade, and then cut. A method for producing glass beads, characterized in that the obtained glass granules are sphericalized by utilizing their surface tension.