Orifice plate for use in bushing for spinning glass fibers

Abstract

Disclosed is an orifice plate for use in a bushing for spinning glass fibers having a number of orifices each of which consists of two cascaded coaxial cylindrical bores of different diameters, one of which opens in the upper surface of the orifice plate to constitute a molten-glass inlet-side bore, while the other opens in the lower surface of the orifice plate to constitute a molten-glass outlet-side bore. The orifices are so densely arranged as would allow joining of molten glass cones formed at adjacent orifices if a suitable countermeasure such as a cooling by air flow were not taken. In order to compensate the reduction of flow rate of the molten glass through the outermost orifices attributable to a larger ratio of heat radiation to heat absorption at the outermost orifices than at the inner orifices, a specific dimensional relationship is provided between the outermost and the inner orifices such that glass cones of the same size and shape with those of glass cones of inner orifices are formed at the outermost orifices irrespective of the difference of the heat radiation between the outermost and the inner orifices, thereby to decrease the frequency of occurrence of breakage of filaments at the outermost glass cones which has often taken place to interrupt the continuous spinning.