Abstract: By controlling the design and operational parameters in accordance with particular relationships fibers having an average diameter of 7 microns or less can be formed by passing molten material through orifices in a peripheral wall of a rotor without using conventional hot gas blast attenuation externally of the rotor. The primary fibers are broken into finite lengths to produce staple fiber by a plurality of relatively cool and relatively low pressure air streams which are circumferentially spaced about the rotor and which flow in a direction transverse to the direction of travel of the primary fibers as they exit the orifices in the rotor. The rotors utilized in the perferred embodiment of the present invention have a peripheral wall with at least 40,000 orifices having diameters of about 18 mils or less.

Abstract: A two-stage orifice outlet is provided for an electric furnace. The structure defining the inner orifice adjacent the interior of the furnace through which molten material passes in its initial stages of withdrawal from the furnace is made of a refractory metal to withstand the high temperatures present within the furnace and this refractory metal must be protected from the oxidizing effects of air. The outer structure defining the outer orifice is made from a more oxidation resistant material and acts as a shield to prevent the oxidation of the refractory metal inner orifice. The outer orifice is maintained below a temperature at which it will undergo rapid deterioration by the use of cooling means. The outlet described above is operated without injecting neutral or reducing gases into the area surrounding the furnace outlet as was required by prior art furnaces of this type.

Abstract: Attempts have been made by the prior art to oscillate a veil of air entrained centrifugally spun fibers back and forth across a moving collecting surface to build a layer of fibers having uniform thickness and density. The present invention accomplishes this objective by oscillating a fiberizing rotor, preferably about an axis that runs through the bottom wall of the spinner.

Abstract: Prior art high temperature electric furnaces of the type using two or more, usually three, primary electrodes positioned around an electrically conducting central outlet brought the electrodes in through a side or bottom wall of the furnace at points below the melt line causing many problems. The present invention provides a primary electrode arrangement for such melting furnaces wherein the primary electrodes do not pass through the wall or bottom of the furnace below the melt line, but instead enter the furnace over the top of the melt line and then protrude through the top surface of the melt. The primary electrodes of the present invention are provided with means for preventing wear and deterioration at the interface between the top surface of the melt and the unmelted batch and/or the oxidizing air atmosphere surrounding the top of the furnace. The improved furnace of the present invention does not require the use of a purging neutral or reducing atmosphere to protect the primary electrodes.