JPS63239136A - Production of inorganic fiber - Google Patents

Abstract

PURPOSE:To reduce the content of particles in the formed fiber and to improve the quality of the fiber by increasing the centrifugal acceleration or peripheral velocity of the rotary drum of a multistage rotary drum type centrifugal fiberizing device in the production of inorg. fiber by the device. CONSTITUTION:The melt as the material for producing the inorg. fiber such as rock wool and glass wool is supplied to the multistage rotary drum type centrifugal fiberizing device, and inorg. fiber is produced. In this case, the centrifugal acceleration or peripheral velocity of the rotary drum is increased to reduce the content of the particles in the inorg. fiber. As a concrete production method, the mean centrifugal acceleration of the rotary drum from the second stage on is increased to >=10X10<3>G, hence the content of the particles having >=88mu diameter in the inorg. fiber can be reduced to <=20%, and the content of the particles having >=177mu diameter in the inorg. fiber can be reduced to <=10% by increasing the acceleration to >=15X10<3>G.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for forming inorganic fibers.

More specifically, it reduces unfiberized particles mixed into Rm-free cloth! This invention relates to an IINization method.

[Conventional technology]

Non-RIJ&'+L is called rock wool, glass wool, slag wool, mineral wool, etc.
The molten raw material is made into fibers by bringing it into contact with rotating bodies of various shapes or by flowing it down. In particular, devices are commonly used that produce fibers by flowing them down onto the circumferential surface of a multi-stage rotating drum.

A multi-stage rotating drum type centrifugal fiberizing device consists of two to five relatively thin drums arranged horizontally in a staggered manner, with rotating axes parallel to each other and viewed from the front of each drum. A water-cooled cylindrical rotating drum is rotated at high speed.

On the other hand, the molten material melted by a raw material melting device such as a cupola or electric furnace is supplied to the circumferential surface of the first stage rotating drum, and then sequentially applied to the circumferential surface of each of the lower drums such as the second and third stages. The fibers are transferred and spread thinly, and centrifugal force releases the fibers from each drum.

Conventionally, the average centrifugal acceleration of the rotating drum (rω2, where r is the drum radius and ω is the angular velocity, expressed as a multiple of the acceleration G of m force) is normally operated at 4.5 to 7.0 x 10"G. At this time, the content of unfiberized particles (usually called shot) mixed into the fibers is indicated by the size of the scale, but typically the shot content is 88μ or more.

) The content is about 25 to 30%.

The cause of the generation of particles is that minute particles play the role of pulling fibers during fiberization, and they have fiber tails and ta
In some cases, inclusion of a certain amount is unavoidable due to fiber formation. However, large particles of 200μ or more are generated due to turbulence in the flow of the melt flowing down to the first rotating drum, due to collision with the drum, or due to a film-like split flow of the melt spread around the drum circumference. It consists of things that scatter in a wave pattern, or things that are generated when a layer stuck to the drum surface peels off.

Considering the phenomena that are thought to be the cause of these occurrences, it is thought that even if the diameter of the rotating drum is increased or the rotational speed of the drum is increased, it will also increase the generation of particles at the same time, and the particle content will not necessarily increase. Until now, it has not been possible to reduce the

[Problem that the invention seeks to solve]

As mentioned above, the conventional multistage rotating drum type centrifugal fiber forming apparatus has a problem in that the content of shot in the fibers is as high as 25 to 30%, expressed as a particle content of 88 μm or more.

The purpose of the present invention is to reduce this particle content to 20% or less.

In particular, the present invention aims to reduce the particle content by adjusting the operating conditions of a multi-stage rotating drum type centrifugal fiberizing apparatus.

[Means for solving problems]

The present inventors have conducted research to solve the above-mentioned problems, and found that the causes of particle generation are various factors as mentioned above. Although it is important to prevent scattering during collision, and to blow the fibers forward due to the difference in mass between the generated fibers and particles, such as the wind speed of the air plenum, it is important to consider these other factors as conditions for reducing particles as much as possible. The inventors have discovered that, surprisingly, the number of shots can be significantly reduced by increasing the centrifugal acceleration of the rotating drum under the operating conditions of the rotating drum, and has completed the present invention.

That is, the present invention relates to the production of plain carpet, which is characterized in that the particle content is reduced by increasing the centrifugal acceleration or circumferential speed of the rotating drum in the process of manufacturing fibers using a multi-stage rotating drum type centrifugal fiber forming apparatus. It's a method.

It is convenient to take the average value of the centrifugal acceleration of the rotating drums, but it is also the same if we take the total value of the centrifugal accelerations of each drum. Since the first stage rotating drum plays the role of disk 1~reviewer, the centrifugal acceleration of the first stage rotating drum may be added and averaged, or the total value may be taken, but in order to further increase the correlation function, In this case, it is preferable to increase the total value or average value of the centrifugal acceleration of the rotating drums in the second and subsequent stages. The centrifugal acceleration of a rotating drum is a value expressed as rω2, where the radius of the drum is r and the angular velocity is ω.The unit for taking rω2 as the average value of each drum is m.
/5eC2, but it is usually expressed in terms of how many times the acceleration G of gravity is.

As a result of research, the relationship between rotating drum centrifugal acceleration and particle content is expressed by the following equation.

If the particle content (%) of 297μ or more is expressed as Ws-31 The particle content (%) of 77μ or more is expressed as Ws-1, the particle content (%) of 288μ or more is expressed as Ws-1. W = 5.85-0.281 X10 -3r(,,2 W =18.9-1.02X10-3rω2W
=34.0-1.35X10'rω2 However, [ω2
is the average centrifugal acceleration after the second stage, that is, increasing the average centrifugal acceleration can reduce the particle content. A theoretical consideration of this is as follows. Comparing the fiber quality "Jiber" and the shot quality mm5hot, mfiber<<"5hot, the difference in kinetic energy between them is E = -r ω (m - m)
becomes. rotation de 2 5hot fibo
This is because as the centrifugal acceleration of the r-ram increases, the difference in kinetic energy increases, the difference in flight distance due to the high-speed airflow of the air plenum increases, and the separation efficiency due to the high-speed airflow of the air plenum improves.

In order to make the content Ws-i of particles of 88μ or more 20% or less, rω may be set to 10.4xlO''G or more.

Since the centrifugal acceleration is expressed as rω2, specifically, increasing the centrifugal acceleration involves increasing the diameter of the rotating drum and increasing the rotational speed.

Since it is effective as a square, increasing the rotation speed is particularly effective. Therefore, increasing the centrifugal acceleration also increases the peripheral speed rω.

〔Example〕

Using a 4-stage rotating drum type centrifugal fiberizing device, the drum diameters were 360 #1111φ, 400 #1111φ, 400 #1111φ, 460mmφ, and 5 mm.
For the case of 4ONRφ, the centrifugal acceleration was varied.

In this case, the test was carried out under the same conditions as the flow conditions of the melt from the raw material melting device to the first rotating drum, the wind speed of the Air Blenheim, the wind m, etc.

The horizontal axis shows the average centrifugal acceleration (corresponding to the total centrifugal acceleration) of the rotating drum after NO2, and the vertical axis shows the average centrifugal acceleration of the rotating drum after NO2.
The test results for the particle content of 8μ or more and the particle content of 177μ or more are shown in FIG.

It is clear that by increasing the centrifugal acceleration, the particle content can be reduced linearly.

The particle content of 88 μm or more is reduced more widely than the particle content of 177 μm or more. It is clear that centrifugal acceleration is more effective in reducing small diameter particles, whereas larger diameter particles depend on factors such as melt flow conditions.

(Effect of the invention) In the production of R-line fibers using a multi-stage rotating drum type centrifugal fiber forming apparatus, the flow conditions of the raw material melt to the first rotating drum, the air speed, air volume, etc. of the air brenum are kept constant. In this case, the particle content in the generated IIIi fibers can be significantly reduced by increasing the centrifugal acceleration or circumferential speed of the rotating drum. The practical effect on improving the quality of non-RM miscellaneous products is extremely large.

[Brief explanation of drawings]

FIG. 1 is a chart showing the relationship between the average centrifugal acceleration (corresponding to the total value of centrifugal acceleration) and particle content after No. 2 rotating drum. Applicant's agent Hiroshi Fujimoto *kiJrJR
An order*tllL (X? 0t(NO') )I key 2 Fig.

Claims (1)

[Claims] 1. Production of inorganic fibers using a multi-stage rotating drum type centrifugal fiber forming apparatus, characterized in that the particle content is reduced by increasing the centrifugal acceleration or circumferential speed of the rotating drum. Method. 2. The average centrifugal acceleration of the rotating drum from the second stage onwards is @rω
＾2＠, and the content of particles of 88μ or more in the inorganic fiber is W
When _s_-_1 (%) W_s_-_1=34.0-1.35×10^-^3@
The method for producing inorganic fibers according to claim 1, wherein the particle content is reduced by increasing the average centrifugal acceleration according to the formula rω^2@. 3. The average centrifugal acceleration of the rotating drums from the second stage onwards is @rω
＠2＠, and when the content of particles of 177μ or more in the inorganic fiber is W_s_-_2 (%), W_s_-_2=18.9-1.02×10＾-＾3＠
The method for producing inorganic fibers according to claim 1, wherein the particle content is reduced by increasing the average centrifugal acceleration according to the formula rω^2@. 4. The average centrifugal acceleration of the rotating drum from the second stage onwards is @rω
＠2＠, and when the content of particles of 297μ or more in the inorganic fiber is W_s_-_3 (%), according to the formula W_s_-_3=5.85-0.281 ×10＾-＾3＠rω＾2＠ , by increasing the average centrifugal acceleration,
The method for producing an inorganic fiber according to claim 1, which reduces the particle content. 5. The method for producing inorganic fibers according to claim 1, wherein the control value for the centrifugal acceleration or circumferential velocity is the total value of the centrifugal acceleration or the total value of the circumferential velocity of the rotary drums from the second stage onwards, respectively. 6. The method for producing inorganic fibers according to claim 1, wherein the control value for centrifugal acceleration or circumferential velocity is the average centrifugal acceleration or average circumferential velocity of the rotating drums from the second stage onwards, respectively. 7. The average centrifugal acceleration of the rotating drums from the second stage onwards is 10x
10^3 or more, the method for producing inorganic fibers according to claim 1, wherein the content of particles of 88μ or more in the inorganic fibers is reduced to 20% or less. 8. The average centrifugal acceleration of the rotating drums from the second stage onwards is 15x
By setting it to 10^3G or more, 177 in inorganic fibers
The method for producing inorganic fibers according to claim 1, wherein the content of particles larger than μ is reduced to 10% or less.