FI60189C - ANORDINATION FOR FRAMSTAELLNING AV MINERALULL - Google Patents

Description

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Patent and Registration Office .... , , , . ,. . . . , (44) Date of issue and date of issue. -

Patent-och registerstyrelsen 'Ansekan uttagd och utl.skrift «n publksrad 31.08.8l (32) (33) (31) Pyydetty etuoikeus — Begird prloritet 01.09.75

Denmark-Danmark (DK) 3916/75 (71) Rockwool International A / S, 501, Hovedgaden, DK-26U0 Hedehusene,

Denmark-Danmark (DK) (72) Verner Nielsen, Hellerup, Hobert Manfred Rasmussen, Hvidovre,

Danish-Danmark (DK) (TU) Oy Kolster Ab (5U) Apparatus for the production of mineral wool - Anordning för framställning av mineralull

The invention relates to an apparatus for producing mineral wool, which apparatus comprises at least one rapidly rotating rotor on the circumferential surface of which a melt flows in such a way that the melt adheres to the circumferential surface and is ejected in the form of molten fibers cooled and conveyed by a stream of air.

In the production of mineral wool, a fluid stream of melt, usually at a temperature of between 1000 and 14 ° C, is obtained by melting rock types, slags, glass-forming raw materials as well as other inorganic substances in a melting furnace, usually a dome furnace, down to - usually 4: Ile - the surfaces of rapidly rotating rotors. The rotors rotate in pairs against each other, with the main stream of melt being ejected from the top rotor to the next and so on until all the melt is ejected from the rotors in the form of molten fibers. This process is called the normal or cascade spinning process. the outer contour of the rotor set. To avoid cooling the melt stream between the rotors, no air is introduced into the space between the rotors, but air is blown in approximately parallel to the axes of the rotors.

Mineral wool products made by the process described above often provide unsatisfactory tensile strength, which is a disadvantage in finished products that are easily torn in half during transport and construction, but can also resist certain machining processes in which mineral wool is assembled into a relatively thin layer on a conveyor belt which is doubled to a greater thickness. Even low tensile strength occurs in mineral wool products with a low bulk density and results in a product with a bulk density of 20 kg / m 2, which is also economically advantageous, not achieving sufficient strength to be handled during transport and construction.

It is an object of the present invention to provide an apparatus for producing mineral wool, whereby products having a higher tensile strength than before can be produced.

This object is achieved by a device which is characterized by what is apparent from the requirement.

It is assumed that the reason for the relatively low tensile strength of mineral wool produced by the cascade spinning process is that a substantial amount of mineral wool is composed of bundles of mineral wool and not primarily of evenly distributed mineral wool fibers. The size of the bundles can be up to a few centimeters, and in many cases the bundles may have a density greater than the average density targeted in the product containing them. The fiber content in the parts between the bundles may become too low to provide sufficient and satisfactory binding in these parts, so that the bond breaks when the mineral wool is subjected to traction during normal handling.

According to studies, the formation of bundles is due to the fact that in the cascade spinning process, the areas around the rotor during spinning in the area closest to the rotor circumference form a uniform gauze which is somewhat pulled by rotor rotation due to mechanical contact with the rotor. , and which at the same time is to some extent subjected to traction in the direction of the rotor axis by the ambient air flow until the gauze is torn by the air flow to bundles consisting of felted, solidified fibers. j

It has been found that mineral wool products made in the device according to the invention achieve approximately twice the tensile strength compared to mineral wool products of the same density and made by a known process. The higher tensile strength is assumed to be due to a more even distribution of the fibers in the mineral wool product, which is due to the lower density in the coarse mineral wool bundles.

The vanes are thus placed on the flange for each rotor, while the flange forms the second interface of the gap, while the second interface is formed by the air distribution chamber placed around the rotor. In this case, a good harmony is obtained between the tangential velocity component and the circumferential velocity of the rotor.

However, the vanes may also be fixed at an angle to the air distribution chamber. In this case, it becomes possible (ί to vary the amount of air blown in and its direction along the circumference of the rotors, so that the amount of air blown in in areas where the rotors are contiguous can be limited so that the melt does not cool too much.

In this case, it may be expedient to place a damping guard around the area where the melt is introduced into the rotor.

The invention is described in more detail below with reference to the exemplary embodiments shown in the drawing. In the figures, Figure 1 shows a diagram for explaining the method according to the invention, Figure 2 shows a cross-section of a rotor and an air distribution chamber in an embodiment in which the vanes are placed on the rotor, Figure 3 shows a section along line AA in Figure 2.

K 60189

Figure 1 shows a rotor 1 whose direction of rotation is o-indicated by an arrow 0. A flowing stream of melt flows downwards towards the circumferential surface 10 of the rotor, whereby the melt adheres to the surface and then rotates along the body before the melt is ejected from the surface in the form of molten fibers. Along the circumferential surface 10 there is a slot 11 concentric with the rotor 1 for blowing in a stream of air, the purpose of which is to transport away and cool the fibers. Fans are arranged in the slot 11, which ensure that the air flow blown in axially at the speed V indicated by the vector V simultaneously receives a tangential speed component in the direction of rotation of the rotor.

By blowing cooling air in this way, a larger opening is achieved in the gauze formed by the molten fibers surrounding the rotor before the fibers in the form of larger or smaller bundles are applied to an air permeable belt, below which air is sucked out, causing the molten fibers to deposit into mineral branches.

Figure 2 shows a partial section of an axial section through a rotor 1 mounted on a shaft 5 rotating in a shaft bearing 6. The rotor 1 comprises a wheel circumferential surface 10 and rotor flanges 2 and 3. The flanges and the wheel flange are held together against the chest 5a on the shaft by a nut * 4. An air gap 11 is formed along the circumference 10 between the collar of the inner flange 3 and the wall 7 of the air chamber surrounding the shaft bearing. Wings 8 are placed in the slot, which are attached to the collar in the rotor flange 3. The vanes 8 run mainly axially and provide a tangential velocity component to the air flow coming through the slot 11 due to the rotation of the vanes.

Figure 3 shows a section along the line AA in Figure 2, from which it can be seen that the vanes 8 run mainly axially.

The design of Figure 2 has the advantage that the tangential velocity component not only becomes parallel but also equal to the velocity of the circumferential surface at the gap in question. In addition, the bearing housing required for bearing 6 can be used as an air chamber, which makes it easier to keep the s 60189 chamber clean during use. The disadvantage of this design is that there must necessarily be a certain space of movement between the wings and the collars in the wall of the air chamber. Air coming through the motion space can create unintentional vortices.

According to the invention, a thermal insulation board containing a binder with a density of 29 kg / m 3 is produced. Binder-containing mineral wool products are the most common. In such products, the mineral wool fibers are firmly bonded to each other at the points where they contact each other by small aggregates of binder. The thermal insulation board in question contained phenolic resin as a binder and accounted for 1.45% by weight of product 2. The tensile strength for this thermal insulation board was 11.0 kN / m. For comparison, a thermal insulation board having the same density and binder content and prepared by the previously known cascade spinning method had a tensile strength of 6.3 kN / m.