Method and apparatus for forming glass flakes and fibres

Abstract

Apparatus for forming fibres or flakes of material comprises means (1) for producing a heated stream of molten material (9), means for feeding the stream in a substantially vertically downward direction and means (7) for receiving the downwardly directed stream and for forming fibres or flakes therefrom. The apparatus includes means (11, 13, 15, 17) for effecting a change in the temperature of the stream subsequent to the production thereof whereby fibres or flakes of a desired thickness are obtained. Instead of, or in addition to, the temperature changing means, there may be provided means for controlling the mass or volume flow of the stream. The invention also provides methods corresponding to the apparatus.

Description

FIELD OF THE INVENTION [0001] The invention relates to methods and apparatus for forming flakes or fibres of glass or of other similar materials, including ceramic material. [0002] The present invention is applicable to any material which melts when heated and is capable of being formed into flakes and fibres. Such entities are increasingly being used for the reinforcement of plastics or other composite materials. BACKGROUND TO THE INVENTION [0003] In our European patent specification No 0 289 240 there is disclosed apparatus for forming flakes of material from a heated stream of molten material. The apparatus comprises means for feeding the stream in a downwards direction into a rotating cup, the cup being arranged with its open mouth facing upwardly such that molten material within the cup is caused to flow over the upper edges of the cup and flow outwards in a radial direction due to centrifugal force. The apparatus also includes a pair of spaced apart substantially parallel plat...

AI Technical Summary

Benefits of technology

[0010] In a further embodiment in accordance with the present invention, the apparatus is alternatively or additionally by provided with means for cooling the stream prior to it being fed in a downward direction. The cooling means may include a conduit through which the stream is fed, said conduit being surrounded by a cooling coil or jacket through which an appropriate cooling fluid, such as air, may be fed. The effect of cooling the stream within the conduit is to solidify an outer region of the stream in the vicinity of the outlet from the conduit. In this way, the volume mass flow of the flow stream is reduced.

Problems solved by technology

As the flow stream is necessarily open to atmosphere between an outlet from which the stream emerges and the spinning device, it is subject to heat loss and variation in temperature.

The loss of heat is detrimental to the production of thin fibres or flake, particularly in the sub-micron range and changes in temperature as small as one degree cause variation in thickness.

This is not only energy wasteful but may cause severe erosion and corrosion of the refractory lining within the tank.

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