GB980057A - Improvements in or relating to wire screens - Google Patents

Abstract

Coating compositions comprise an epoxy resin, a urea-formaldehyde or phenol-formaldehyde resin and solvents. Coating H is made by dissolving the epoxy resin in "Cellosolve" (Trade Mark) acetate, methyl isobutyl ketone, toluene and isophorone, and adding a solution of urea-formaldehyde resin in butanol-ethanol. Coating I is made by dissolving the epoxy resin in "Cellosolve" acetate, toluene and isophorone, stirring in the phenol-formaldehyde resin and adding phosphoric acid.ALSO:A wear-resistant wire screen comprises interwoven warp and weft wires and has a wear-resistant coating only on the knuckle portions of the warp wires or of both warp and weft wires on the side subject to wear. The caps of coating on these knuckle portions have a width substantially equal to the diameter of the knuckle portions and are arranged so as not to restrict the openings between the wires of the screen. The wires may be woven twill, with the knuckles to be coated substantially in one plane. The warps may be of phosphor bronze and the wefts of bronze or brass, and the wefts may be of smaller gauge than the warps. The coating may be a ureaformaldehyde-epoxy or phenol-formaldehyde-epoxy resin applied in a solvent. It may be applied to the wire screen, after this has been lightly abraded and cleaned with a cloth soaked in toluene, by spreading the coating on a flat plate of stainless steel, drying off part of the solvent, pressing the screen on to the film of coating material, removing it, allowing the coating to dry in air and finally baking it. Alternatively, the coating may be applied by passing the screen in contact with a rotating roll which dips into coating material.ALSO:A wear-resistant wire screen, e.g. the wire cloth of a paper-making machine, comprises interwoven warp and weft wires and has a wear-resistant coating only on the knuckle portions of the warp wires or of both warp and weft wires on the side subject to wear. The caps of coating on these knuckle portions have a width substantially equal to the diameter of the knuckle portions and are arranged so as not to restrict the openings between the wires of the screen. The wires may be woven twill, with the knuckles to be coated substantially in one plane. The warps may be of phosphor bronze and the wefts of bronze or brass, and may be of smaller gauge than the warps. The coating may be a urea-formaldehyde-epoxy or phenol-formaldehyde-epoxy resin applied in a solvent. It may be applied to the wire screen, after this has been lightly abraded and cleaned with a cloth soaked in toluene, by spreading the coating on a flat plate of stainless steel, drying off part of the solvent, pressing the screen on the film of coating material, removing it, allowing the coating to dry in air and finally baking it. Alternatively, the coating may be applied by passing the screen in contact with a rotating roll that dips into coating material.