AN APPARATUS FOR THE DEFIBRATION OF MOLTEN MINERAL MATERIAL

Abstract: The apparatus comprises successive centrifuge wheels (1, 1') rotating at high speed; means (3) for directing a gas flow (A) along the circumferential surfaces of the centrifuge wheels for separating fibers (5) from the molten mineral material (2) passed on to the circumferential surfaces and for guiding the fibers to a collecting point; and a bonding agent spraying means (4) for adding a bonding agent (6) to the fibers. In order to provide a controlled and even mixing of the fibers and the bonding agent, a fiber flow controller (7) positioned in the direction of the flow of the fibers is arranged at the end of the centrifuge wheel adjacent to the spraying means of the bonding agent, which controller comprises a gap (10) for directing the bonding agent drops (6) from the spraying means (4) to the fibers (5) flowing by.

Description: An apparatus for the defibration of molten mineral material The invention relates to an apparatus for the defibration of molten mineral material, comprising successive centrifuge wheels rotating at high speed; means for directing a gas flow along the circumferential surfaces of the centrifuge wheels for separating fibers from the molten mineral material passed on to the circumferential surfaces and for guiding the fibers to a collecting point; and a bonding agent spraying means for adding a bonding agent to the fibers. Apparatuses of this type are disclosed in e.g. 5 German Offenlegungsschrift 2,000,020 and Sovjet Patent Specification 937,364. The bonding agent is therein introduced into a spraying means positioned at the end of the centrifuge wheel through the shaft of the centrifuge wheel, whereby the centrifugal force 0 causes the bonding agent drops to be thrown from the nozzles of the spraying means on fibers flowing past. The apparatus disclosed in the German publication comprises a mushroom-shaped spraying means which is attached to the end of the centrifuge wheel at the 5 base portion thereof. The diameter of the spraying means is considerably smaller than the diameter of the centrifuge wheel. The spraying means of the Sovjet publication is conical and attached to the end of the centrifuge wheel at the end having a smaller diameter. 0 In this case, too, the diameter of the spraying means is clearly smaller than that of the centrifuge wheel. The spraying means of both these publications are merely designed to provide the best possible spraying of the bonding agent, and the appearance of the spraying means is determined by this purpose. These spraying means are not even intended to affect the flow of the fibers passing by. Even though these means effect an even spraying of the bonding agent, this alone does not ensure that the bonding agent adheres properly to the fibers, as the fiber flow is usually uneven outside the circumferential surface of the centrifuge wheel. To solve the problem, Finnish Published Specification 71,118 suggests that the diameter of the spraying means of the bonding agent should be increased so that the ring-shaped orifice of the spraying means will be positioned very near the circumference of the centrifuge wheel, i.e. near the fiber flow. However, the drop formation of the bonding agent is difficult to control, and therefore the bonding agent is not mixed up evenly with the fibers. The object is to provide a new apparatus which avoids the prior problems and enables the bonding agent to be mixed up with the fibers, i.e. to be adhered thereto, evenly and in a controlled manner. This object is achieved by means of an apparatus according to the invention, which is mainly characte¬ rized in that in order to provide a controlled mixing of the bonding agent with the fibers a fiber flow controller positioned in the direction of the flow of the fibers is arranged at the end of the centrifuge wheel adjacent to the spraying means of the bonding agent, whereby the controller further defines a gap for directing the bonding agent drops from the spraying means to fibers flowing by. Thus, the invention is based on the idea that the circumference of the centrifuge wheel, from which the molten material is thrown, is provided with an extension part so shaped that the gas flow containing the fibers will have a desired flow profile and that the bonding agent drops, prefereably produced by means of a small diameter spraying means, are directed 5 outwards in a controlled manner at least essentially up to the circumference of the centrifuge wheel, wherefrom they are mixed with the fibers. A flow field of the gas flow containg the fibers is created around the fiber flow controller positioned in the direction 10 of flow of the fibers, which field efficiently captures and distributes the bonding agent thrown from the centrifuge wheel. The fibers are passed through a bonding agent cload in good order as an even continuous flow. Since the bonding agent is distributed evenly 15 over all fibers, the obtained product is of higher quality. The flow controller prefereably comprises two portions, a gap being defined therebetween for the passage of the bonding agent, and prefereably at 20 least that portion of the flow controller which is positioned adjacent to the centrifuge wheel is integral with the centrifuge wheel. By virtue of this structure, the shaped end of the centrifuge wheel can be used to form part of the flow controller. The 25 end of the centrifuge wheel is easy to shape in connec¬ tion with the manufacture of the centrifuge wheel. The spraying gap of the bonding agent can thereby be positioned as desired and at a point more advantageous in view of the flows. p- 30 In the following the invention will be described with reference to the attached drawing, wherein Figure 1 shows one preferred embodiment of the apparatus according to the invention, and Figure 2 shows another embodiment of the appara- tus according to the invention. Figure 1 shows one of the centrifuge wheels of a mineral wool defibrator, which wheel is designated by the reference numeral 1. In the same way as disclosed in e.g. Finnish Published Specification 71,118, a molten material mineral 2 is thrown from a circumferential surface 8 of the centrifuge wheel 1 rotating at high speed. For passing those particles of the molten material 2 which are to be changed into fibers 5 into a receiver, a fan 3 is arranged around the circumference of the centrifuge wheel at one end of the centrifuge wheel to provide a forceful air flow A which is directed along the circumferential surface of the centrifuge wheel in the axial direction of the wheel. A calotte- shaped flow controller 7 tapering in the direction of the air flow A and the fibers 5 and comprising two parts 7a and 7b is arranged at the opposite end of the centrifuge wheel. A circumferential surface 9 of the first part 7a adjoins the circumferential surface 8 of the centrifuge wheel. A gap 10 is defined between the parts 7a and 7b of the controller, through which gap the centrifugal force causes the bonding agent drops 6 to be directed to the fibers 5 flowing by. A bonding agent spraying means 4 sending the bonding agent drops 6 ispositioned within the first part 7a of the flow controller so as to be in communication with the gap 10, whereby the bonding agent is introduced into the spraying means through the rotary shaft of the centri¬ fuge wheel and the diameter of the spraying means is preferably essentially smaller than that of the centri¬ fuge wheel. If the flow controller 7 were a one-piece part, the gap 10, into which the bonding agent spraying means 4 opens, would be positioned immediately after the centrifuge wheel (in Figure 1 between the parts 1 and 7a) . When the centrifuge wheel 1 rotates at high speed, the air flow A takes therewith those particles of the molten material 2 which are to be converted into fibers 5 and passes them towards the other end of the centrifuge wheel, where they enter a bonding agent cload formed by the bonding agent drops intro¬ duced through the gap 10 from the bonding agent spraying means 4 under the influence of the centrifugal force. The calotte-shaped flow controller 7 rotating with the centrifuge wheel creates around it a flow field of the blast air A, which field is such that the fibers 5 are caused to pass close to the surface of the flow controller in good order. In this way the fibers are prevented from being carried past the bonding agent cload nor do they form clusters as a result of which only part of the fibers would get ' in contact with the bonding agent. The apparatus according to Figure 2 is similar to that of Figure 1 with the exception that a flow controller 7' attached to a centrifuge wheel 1' is formed by two truncated cones 7a' and 7b 1 of which one cone 7b' has a sharper conical angle. The drawing and the description related thereto are only intended to illustrate the idea of the invention, The structure and shape of the flow controller may vary within the scope of the attached claims.

Claims: Claims 1. An apparatus for the defibration of molten mineral material, comprising successive centrifuge wheels rotating at high speed; means for directing a gas flow along the circumferential surfaces of the centrifuge wheels for separating fibers from the molten mineral material passed on to the circumferen¬ tial surfaces and for guiding the fibers to a collect- ing point; and a bonding agent spraying means for adding a bonding agent to the fibers, c h a r a c t e ¬ r i z e d in that for mixing together the bonding agent and the fibers a fiber flow controller (7, 7 1 ) positioned in the direction of the flow of the fibers is arranged at the end of the centrifuge wheel (1,1') adjacent to the spraying means (4) of the bonding agent, which controller at the same time defines a gap (10) for directing the bonding agent drops (6) from the spraying means (4) to the fibers (5) flowing by. 2. An apparatus according to claim 1, c h a r a c t e r i z e d in that the flow controller (7, 7') comprises two parts (7a, 7b,; 7a', 7b') which define therebetween the gap (10) for directing the bonding agent drops (6) to the fibers (5) flowing by. 3. An apparatus according to claim 2, c h a r a c t e r i z e d in that at least that part (7a; 7a') of the flow controller (7; 7') which is positioned on the side of the centrifuge wheel (1; 1') is integral with the centrifuge wheel. 4. An apparatus according to claim 1, c h a r a c t e ri z e d in that the flow controller (7, 7') essentially has the shape of a body of revolu¬ tion. 5. An apparatus according to claim 2, c h a r a c t e r i z e d in that the parts (7a 1 , 7b') of the flow controller have the shape of a truncated cone. 6. An apparatus according to claim 4, c h a r a c t e r i z e d in that the flow controller (7; 7') is calotte-shaped. 7. An apparatus according to claim 4, c h a r a c t e r i z e d in that the flow controller (7; 7') is semi-spherical in shape. 8. An apparatus according to claim 4, c h a r a c t e r i z e d in that the flow controller (7; 7') is cylindrical in shape.

Inventors: HJERPPE PERTTI KALEVI, JOHANSSON LASSE KARL MIKAEL, STRAND ERIK AXEL, HJERPPE, PERTTI, KALEVI, JOHANSSON, LASSE, KARL, MIKAEL, STRAND, ERIK, AXEL
Applicants: PARTEK AB, OY PARTEK AB
Application year: 1987
Main classification: C03B37
IPC codes: C03B37, C03C25