JPS602257B2 - How to remove shot from inorganic fibers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the production of unfiberized filaments (with a diameter of about 100 to 400 mm), commonly called shot, which are produced during fiberization in the manufacturing process of inorganic fibers such as glass fibers, rock wool, and ceramic fibers. This invention relates to a method for removing inorganic particles using a high specific gravity difference.

Conventionally, inorganic fibers have been manufactured by a centrifugal method, a flame blowing method, or a modification thereof, and each of these manufacturing methods contains shot, although there are some differences. It is no exaggeration to say that the amount of shot greatly affects the commercial value of the inorganic fiber product. If shot is mixed in inorganic fibers, for example, when used as a heat insulating material, not only will the shot stick to the hands or cause irritation during installation, causing safety and health problems, but the original heat insulating performance will also deteriorate. come. Especially when making paper-like filters or packings using ultra-fine glass fibers or other ceramic fibers mixed with shot, the shot tends to peel off easily, resulting in holes or thinning of the part during use. It can no longer be used as a filter or packing material. Such shots have various shapes such as rod-like, granular, and hook-like shapes, and when they are mixed in inorganic fibers, the inorganic fibers become entangled with each other, so it is extremely difficult to remove only the shots. I understand.

The inventor conducted various studies on the rising speed of inorganic fibers and the shot removal rate due to the conveying airflow in the duct using a vertical hollow duct, and found that the shot removal rate was good within a certain range of rising speed. see something, bring it out,
The present invention has now been completed.

The present invention is a method for removing shot from inorganic fibers, which is characterized in that the shot-containing inorganic fibers are raised in a vertical hollow duct at a speed of 0.2 to 0.6 m'sec by a conveying air flow. .

The greatest feature of the present invention is that the inorganic fibers containing shot can be reduced to zero.
．． The purpose is to raise the vertical hollow duct at a rate of rise in the range of 2 to 0.6' seconds.

If the rising speed of the inorganic fibers is slower than the above range, the inorganic fibers will adhere to the shot and fall together to the bottom of the vertical hollow duct, resulting in a poor recovery rate of the inorganic fibers. Also 0.6m/
If it exceeds sec, the shot will be entrained in the inorganic fibers, making separation impossible and reducing the removal rate. To achieve the intended purpose of the invention, the rate of rise is kept in the range of 0.2 to 0.6 skins/sec, particularly preferably 0.3 to 0.5 skins/sec.

The inorganic fibers applicable to the present invention include glass fibers, rock wool, ceramic fibers, etc., and in particular, the grain size is 0.1 to 1.
It is suitable for producing so-called ultra-fine inorganic fibers having a fiber length of about 0.1 to 5 degrees, especially ultra-fine glass fibers.

The present invention will be described below with reference to the accompanying drawings, but the present invention is not necessarily limited thereto, and various modifications may be made as necessary without departing from the gist of the present invention. Of course, it is possible.

FIG. 1 is a diagram showing a typical embodiment of the present invention.

1 in the figure is a spinning furnace, into which raw inorganic substances are charged and melted at high temperatures. Next, the melt is taken out of the spinning furnace 1 as a filament 2, and is fiberized by a high-speed air stream, such as the discharged gas of the jet burner 3 or high-pressure compressed gas, and the gas acts as a carrier air stream. It passes through the introduction duct 4 and is led to a vertical hollow duct 5 that converts the flow of the carrier air stream into an upward air stream. This vertical hollow duct 5
Within the range, the rising speed of the rising air current is maintained within the range of 0.2 to 0.6'sec. If the rising speed is slower than the above range, the inorganic fibers will fall along with the shots, making it impossible to effectively remove the shots.On the other hand, if the rising speed is further than the above range, the shots will be accompanied by the inorganic fibers, making it impossible to remove the shots. is not done enough. When the rising speed is within the range of 0.2 to 0.6/sec,
Only the shot in the inorganic fiber falls due to the difference in bulk specific gravity,
It collects at the bottom of the vertical hollow duct 5. A shot recovery port 7 or a shot extraction device 8 may be provided at the bottom as appropriate. Meanwhile, while separating the shot, the inorganic fibers ascend within the vertical hollow duct 5 and are recovered by the inorganic fiber recovery device 6.

At the upper part of the vertical hollow duct 5, a conveying air outlet 9, a suction fan 10, etc. may be provided as appropriate. In the present invention, the rising speed of inorganic fibers in a vertical hollow duct is set to 0.
．． The method of maintaining the velocity at 2 to 0.6'sec is based on the flow rate of the carrier airflow, the diameter of the carrier airflow introduction duct and the vertical hollow duct,
Various requirements such as the shape such as the length and the introduction angle of the carrier airflow introduced into the vertical hollow duct may be controlled.

It is also possible to add external requirements such as blowing air in from the bottom of the vertical hollow duct or suctioning it from the top of the vertical hollow duct. The vertical hollow duct used in the present invention may have any structure as long as it converts the conveying airflow into an upward airflow, but its basic structure is that the bottom plate receives the falling shots, the top has inorganic fibers and the conveying air flows through the bottom plate. It has a cylindrical, box-like, etc. shape with an outlet and a conveying airflow introduction duct between them.

Although it is generally desirable that the vertical hollow duct be installed vertically, it may also be installed at a certain degree of inclination.
In the vertical hollow duct of the present invention, the conveying air flow introduction duct 4 is provided at a position from the bottom plate of the vertical hollow duct 5 that satisfies the requirements of the following equations {1} and {2). It was found that the removal rate was further improved. D/
1=1.2~6.0 ......[1}D2/
d2i6.0~83.0・・・・・・・・・
・[2) (D is the inner diameter of the vertical hollow duct) (d is the inner diameter of the carrier airflow introduction duct) (1 is the distance from the bottom plate of the vertical hollow duct to the carrier airflow introduction duct) Furthermore, in the present invention, the vertical type The conveying airflow introduced into the hollow duct is directed at an angle of 5 to 80 degrees, particularly preferably 15 to 45 degrees, toward the center of the duct in the flow direction of the upward airflow.
It was also found that the shot removal rate improved when introduced within the range of

Therefore, in carrying out the present invention, the above-mentioned {1} and ■
A particularly remarkable effect is exhibited when a vertical hollow duct satisfying the formula is used and the conveying air flow is introduced at an angle of 5 to 80 degrees.

As the air flow for conveying the inorganic fibers of the present invention, any inert gas may be used without any restriction, and generally air, nitrogen, carbon dioxide gas, etc. are preferably used.

As described above, the present invention efficiently removes the shot contained in the inorganic fibers by maintaining the rising speed of the inorganic fibers in the vertical hollow duct at 0.2 to 0.6 m/sec. The fibers obtained by carrying out the present invention contain almost no shot.

Therefore, when products are made using this inorganic fiber, good products can be obtained. The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Incidentally, the shot rate was measured by the following method.

Approximately 30% of the inorganic fibers collected from the top of the vertical hollow duct are weighed, and mixed with approximately 1.2% of water in a household mixer for 1 minute to disperse the inorganic fibers. Next, this is left to stand for about 3 hours, a small amount of supernatant liquid is removed, and decantation is repeated while supplying water again to separate the inorganic fibers and shot. The shot that has sunk to the bottom of the mixer is taken into a beaker and dried, then sieved through a 100-mesh knot, and the weight of the shot remaining on the knot is measured. Shot rate = Metsuryo stirrup embankment amount o Example 1 In a vertical hollow duct with an inner diameter (D) of 1.4 and a height of 6.0 m, the conveying air flow introduction duct was installed at a point of 0.2 skin (1) from the bottom. A corner angle of 0 degrees was used.

The inner diameter (d) of the conveying airflow introduction duct was 0.24. Glass fibers containing 4.2% shot ratio (fiber diameter approximately 0.5 French) were introduced into this vertical hollow duct while changing the flow rate of the conveying air flow to achieve the rising speed shown in Table 1, and the shot removal rate was I looked into it. The results are shown in Table 1. Table 1 *Bottom plate K Glass fibers had accumulated.

Example 2 A vertical hollow duct with an inner diameter (D) of 1.8 m and a height of 8.0 m is used to introduce a conveying air flow (inner diameter d = 0.3 m) from the bottom.
．． The test was carried out in the same manner as in Example 1 with a shot content of 4.3% using a test piece provided at a distance of 6 m (1) with an extension angle of 0 degrees.

The results are shown in Table 2. Table 2 *Glass fibers were collected on the bottom plate.

Example 3 The same procedure as in Example 2 was conducted except that glass fiber with a shot content of 4.5% (fiber diameter of approximately 0.5 French) was used and the conveying air flow introduction duct was provided at a forward angle of 22 degrees. The results shown in Table 3 were obtained.

Table 3 *Glass fibers were collected on the bottom plate.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a typical embodiment of the present invention. In the figure, 1 is a spinning furnace, 2 is a filament, 3 is a jet burner, 4 is a conveying air flow introduction duct, 5 is a vertical hollow duct,
Reference numeral 6 represents an inorganic fiber recovery device, 7 a shot recovery port, and 8 a shot extraction device. Tsutomu/Figure

Claims (1)

[Claims] 1 shot-containing inorganic fibers by a conveying air stream.
A method for removing shot from inorganic fibers, which comprises raising the shot in a vertical hollow duct at a speed of 2 to 0.6 m/sec.