| 摘要 |
916,611. Photographic processing apparatus. AGFA A.G. Sept. 15, 1959 [Sept. 22, 1958], No. 31489/59. Class 98 (2). [Also in Group I] A processing liquid such as photographic developer solution is subjected, while in circulation, to pressure-free filtration by passage in a substantially horizontal direction through a filter of mesh diameter 0.2-5 mm. In the developing tank of Fig. 1, liquid is continuously withdrawn from the tank 1 through an upper passage 4 and returned through a lower passage 5, a propeller 7 in the circulating channel 6 providing the driving force. In passage 4 is placed the filter shown in more detail by Fig. 2. The filter is contained in a removable container 18, and is preferably made of a mesh of synthetic resin fibres, joined by synthetic resin adhesive. It may have two different components, i.e. a wide mesh 17a and a smaller mesh 17b. As shown, the wide mesh increases in length in an upward direction, with a corresponding decrease in the length of the narrow mesh component. The narrow mesh will become clogged first, when the liquid can still pass through the wider mesh. Even when that too becomes clogged, the liquid can pass over the top of the filter. In the arrangement of Fig. 3, the filters are in the form of strips 25 extending in a radial direction from the wall of a cylindrical tank 21. Film strips 32 are stretched between supporting spokes 30, 31. A propeller 45 circulates the liquid in the tank by causing it to pass down a central tube 29 and outwards. Solid particles in the liquid tend to move towards the periphery of the tank, where the filters are located, due to centrifugal action. In a further embodiment (Fig. 5, not shown) the propeller is omitted, and the spokes 30, 31 caused to rotate on a central shaft, so that the moving film strips 32 themselves cause the liquid to circulate. At the same time this shaft can be given an axial pulsating or reciprocating motion, to detach solid particles which may be adhering to the film. |
