Patent GB-703622-A (GB)
Title: Improvements in or relating to photographic processing tanks
IPC: G03D13/04
Filed: 1950-08-22
Abstract: 703,622. Photographic processing tanks. ALBERTS, S. S., and ALBERTS, A. S. Aug. 22, 1950, No. 20775/50. Class 98(2) A device for processing photographic negatives comprises a receptacle which includes a chamber for containing a liquid treatment bath, a removable device for holding the negative or negatives to be treated and mounted for rotation about a substantially vertical axis within the chamber, a removable cover providing a light-excluding closure for the chamber, and means within the chamber for interacting with means on the negative holding device for rotating the latter when the cover is in-place. As shown, Fig. 1, a film processing tank has concentric walls 2, 4, and a bottom 3 from the centre of which a shaft 7 extends upwards from a boss 6. A film reel 8 fits rotatably over the shaft 7, and consists of a hollow shaft 9 with spirally grooved flanges 10, 11, of which one, e.g. 11, is adjustable along shaft 9 to accommodate different widths of film. The top of shaft 9 is formed with a shoulder 14 and a flat surface so that an impeller, wheel 13 may fit thereon to rotate with the film reel. The impeller overlies the top of wall 2 but lies within wall 4, and has blades 17 on its periphery projecting down into the space between walls 2, 4. A nozzle is mounted in wall 4 to direct a jet of water against the blades 17, causing the film reel to rotate. The water may be maintained at a required temperature by supplying it from a mixing faucet or thermostatic mixing valve, and fills the space between walls 2, 4 to control the temperature of the processing liquid. The water level is controlled by an overflow 21. A filling spout at the side of the tank receives a funnel, and communicates with a channel 24 extending vertically at one side of wall 4, and communicating with a horizontal passage 25 through which the inner chamber 1 of the tank is filled with processing liquid. The liquid level in chamber 1 is visible through a vertical window 26. Chamber 1 has an overflow 28 and a drain outlet 29. A light-tight cover 30 fits over wall 2, and has a central sleeve 31. fitting into a sleeve 32 on shaft 9. A cam 33 on the lower flange 10 bears on a pin 34, mounted on boss 6, and causes an up-anddown movement of the film reel in addition to its rotatary motion. The impeller vanes 17 are sufficiently long to remain under, the influence of the jet while up-and-down movement takes place; similarly sleeves 31, 32 are long enough to remain overlapped. The arrangement so far described is used for developing, fixing, &c., but for washing the film a second impeller is used, consisting of a flat disc 35 having radial ribs 36 and fast on shaft 9. A second nozzle provides a jet directed against ribs 36 to turn the film reel, the water collecting in chamber 1 to wash the film, and overflowing through the outlet 28. The two jets have valves whereby each may be regulated'or shut off, so that they can be used one at a time. In modifications: (1) the second impeller 35, and the means for causing up-and-down movement, are omitted; (2) the first impeller 13 is omitted and the reel is turned by hand during developing, fixing &c. but is turned by impeller 35 during washing; (3) in a tank for washing, the reel is rotated by a single impeller such as 35 and has no up-and-down movement. The upper flange 11 may be adjustable, instead of the lower flange 10, to allow for different widths of film, and in this case the liquid level is altered by means of an adjustable overflow.