Roller for coating the surface of a film or sheet moving at high speed with liquid.

摘要

A roller for coating the surface of a film or sheet moving at high speed with a liquid comprises a centrtal axial pipe (2) provided with apertures (6) whereby a fluid material fed into the pipe may disperse and permeate through an absorbent felt material (3) forming a roller around the pipe (2). The roller (3) is surrounded by a rigid casing (4) defining an outer profile having peaks (8) and troughs (9) and shaped in the manner of a cog wheel. The casing (4) is lined with an absorbent felt material (5) and fluid passes from the roller (3) throu gh ducts (10) to impregnate the material (5) in the region of the peaks due to centrifugal action. In a method of coating a thin sheet or film material the roller (1) is arranged so that the flat peaks (8) contact the film with the relative peripheral speed of the roller and of the film beisng different and in an embodiment the roller rotates against the direction of movement of the film. The sliding action provides a uniform thin coating on the film whilst air is entrained and exhausted through channels (7) thus preventing splashing and providing a uniform coating.