Restoration of suction press shells

Abstract

A process for restoring a suction press shell used in the removal of water in the formation of paper sheets, the shell consisting of a metal cylinder bonded with a rubber cover and perforated by multiple drainage holes which extend from the inner surface to the outer surface of the shell, the inner surface of the metal cylinder being worn and having lost its uniform aspect, the process comprises the steps of: cleaning and roughening the outer metal surface of the cylinder, winding under tension on the outer surface of the cylinder successive layers of a woven glass or synthetic fiber tape from 2 to 6 inches wide, and impregnating with a concentration of 35 to 55% of thermosetting resin until the required thickness of the tape for stiffening the cylinder within acceptable deflection limits is reached, each layer of tape overlapping the preceding layer by 25 to 90% at an angle of wrap of 5.degree. to 15.degree., winding a reinforcing layer of a transparent cellulose film from 2 to 6 inches wide over the resin impregnated layers, heat treating the cylinder thus wrapped with the cellulose film at a temperature ranging from 212.degree. to 300.degree. F. for 2 to 8 hours to harden the layers of tape, grinding or tooling the outer surface of the cylinder thus heated to uniform surface and to remove the transparent cellulose film therefrom, applying a specially formulated rubber cover over the outer surface thus obtained after removal of the cellulose film, heat treating the rubber cover at 270.degree. to 300.degree.F. for 8 to 20 hours to promote vulcanization and adhesive reaction, redrilling the drainage holes of the cylinder thus completed to restore their normal extension from the inner surface of the metal cylinder to the outer surface of the newly bonded rubber cover, and boring the inside diameter of the metal shell to a uniform surface. The process also provides a good bonding of a rubber cover to the outer surface of the cylinder of the press shell. And, a press shell obtained by the above process.

Dependencies are inferred from the claim text.