Abstract: A method and apparatus for heating fibrous mineral insulation material comprises an oven divided into zones, a conveyor for carrying the insulation material through the oven, means for directing hot gases into contact with the insulation material in the first oven zone, first heating means for heating the hot gases, and second heating means, distinct from the first heating means and positioned upstream from the first oven zone for heating the conveyor.

Abstract: A method and apparatus for heating fibrous mineral insulation material comprises an oven divided into zones, a conveyor for carrying the insulation material through the oven, means for directing hot gases into contact with the insulation material in the first oven zone, first heating means for heating the hot gases, and second heating means, distinct from the first heating means and positioned upstream from the first oven zone for heating the conveyor.

Abstract: The invention relates to apparatus for producing fibers from heat softened mineral material, such as glass. More specifically, this invention relates to an orifice plate for a glass fiber drawing bushing of the type having a flat undersurface and a plurality of orifices formed therethrough with the improvement comprising at least two sets of grooves formed on said undersurface, said grooves extending in intersecting relationship to divide said undersurface into a plurality of sections, said orifices being located within said sections. The grooves can have a width in the range of from aout 0.1 mm to about 1.2 mm and a depth in the range of from about 0.1 mm to about 0.5 mm. The orifice plate can comprise rod members at the intersections of the grooves with said rod members projecting beneath said grooves.

Abstract: The invention relates to apparatus for producing fibers from heat softened mineral material, such as glass. More specifically, this invention relates to an orifice plate for a glass fiber drawing bushing of the type having a flat undersurface and a plurality of orifices formed therethrough with the improvement comprising grooves formed in the undersurface surrounding each orifice. The grooves are spaced from one another such that they not in intersecting relationship.