GB276058A - Improvements in or relating to methods and apparatus for drying photographic films or the like after development - Google Patents

Abstract

276,058. Biscoe, A. E., Stratton, A., and Stringer, H. B. May 17, 1926. Drying materials in long lengths. - Photographic film or paper is dried after development &c., by passing it round and in contact with the surface of a chamber containing hot liquid, while maintaining the sensitized surface outwards in the case of film and inwards in the case of paper; the drying may be assisted by a stream of cold or hot air. The film &c. is fed, after hardening, as in a formalin bath, from a spool 3 preferably first to a squeegee comprising two lips of rubber, and then, over a roller 12 covered with absorbent fabric to remove beads of moisture, to the polished surface of a flanged drum 2, mounted in open-bearings 11, from which it is delivered to a take-up spool 4. The spools and drum are detachably mounted in a casing 1, through which air may be circulated in the direction of the arrows by a fan 5. The air may be heated at, or before reaching the inlet 30, which is preferably covered with gauze to free the air from dust. The ends of the drum are heat-insulated by asbestos, and an aperture in one of them, closed by a screw-cap provides means for introducing hot liquid into the drum. The friction wheels, mounted on a spindle 14 turning in slot bearings in the casing 1, and rotated by a handle 22, are drawn by springs 15 into contact with the periphery of the drum. and the drive is transmitted to the take-up spool 4 by pulley gearing 18, 19, 20 which allows of the necessary slip as film accumulates on this spool. An additional electric heater may be incorporated in the drum, or hot water may be circulated therein through axial passages. Solutions of salts such as sodium carbonate may be used in the drum to obtain a higher maximum temperature. More than one drum may be employed, and for long narrow films such as kinematograph films, a long drum round which the film is wound spirally may be used. Additional rollers may be provided adjacent to the drum to guide the film &c. over a larger are of the periphery of the drum. Reference is made to Specification 275,349, [Class 98 (ii), Photographic processes &c.], in connection with an alternative method for squeegeeing the prints.