Abstract: A tentering apparatus for tensioning a sheet-like member, for example, a membrane used in an electrolyzer. The apparatus includes four clamping assemblies arranged in a frame-shape configuration within an outer frame member, and a fastener, such as a threaded bolt and wing unit, for fastening the clamping assemblies to the outer frame members and for tensioning the sheet-like member.

Abstract: A tentering apparatus for tensioning a sheet-like member, for example, a membrane used in an electrolyzer. The tentering apparatus includes four clamping assemblies arranged in a picture frame shape configuration with four corner members and a connector member for connecting the clamping assemblies to the corner members and adapted for tensioning the sheet-like member.

Abstract: A tentering apparatus for tensioning a sheet-like member, for example, a membrane used in an electrolyzer. The tentering apparatus includes four clamping assemblies arranged in a picture frame shape configuration adapted for clamping at least a portion of its periphery of a sheet-like member. One pair of clamping assemblies have studs at each end rotatably mounted at the ends of the second pair of clamping assemblies. A planar sheet-like member is tensioned by clamping the periphery of the sheet-like member and applying a pulling force generally outwardly and normal to the second pair of clamping assemblies and rotating the first pair of clamping assemblies to cause a pulling force generally normal to the first pair of clamping assemblies.

Abstract: A method of recovering fumed hydrophobic SiO.sub.2, produced by the flame hydrolysis of a ternary azeotrope of H.sub.2 SiF.sub.6, HF, and H.sub.2 O, is disclosed. The method involves passing the fumed hydrophobic silica, as it leaves the combustion chamber, through a nonclassifying agglomerator at a residence (travel) time of from about 0.5 to several seconds, preferably about 1.0 to about 5.0 seconds, then separating the fumed silica from the product stream in a cyclone separator or other means for collecting dispersoids.

Abstract: Fluorosilicic acid solutions, which normally undergo decomposition when distilled, thereby creating unwanted forms of SiO.sub.2, are rendered stable during distillation by providing in the fluorosilicic acid solution an amount of HF which is at least about 10 parts of HF per 36 parts of H.sub.2 SiF.sub.6 and an amount of H.sub.2 O which is at least about 54 parts of H.sub.2 O per 36 parts of H.sub.2 SiF.sub.6. The mixture is distilled to remove any excess H.sub.2 O and excess HF that is present, without encountering formation of SiO.sub.2, until an azeotropic solution containing about 36% H.sub.2 SiF.sub.6, about 10% HF and about 54% H.sub.2 O is reached. The ternary azeotrope, being of constant quality and concentration, is more suitable for use in various processes, such as processes for making fumed SiO.sub.2, than H.sub.2 SiF.sub.6 solutions which are not of constant quality or concentration.

Abstract: Fluorosilicic acid solutions, which normally undergo decomposition when distilled, thereby creating unwanted forms of SiO.sub.2, are rendered stable during distillation by providing in the fluorosilicic acid solution an amount of HF which is at least about 10 parts of HF per 36 parts of H.sub.2 SiF.sub.6 and an amount of H.sub.2 O which is at least about 54 parts of H.sub.2 O per 36 parts of H.sub.2 SiF.sub.6. The mixture is distilled to remove any excess H.sub.2 O and excess HF that is present, without encountering formation of SiO.sub.2, until an azeotropic solution containing about 36% H.sub.2 SiF.sub.6, about 10% HF and about 54% H.sub.2 O is reached. The ternary azeotrope, being of constant quality and concentration, is more suitable for use in various processes, such as processes for making fumed SiO.sub.2, than H.sub.2 SiF.sub.6 solutions which are not of constant quality or concentration.