GB885283A - Improvements in or relating to colour sorting machines - Google Patents

Abstract

885,283. Photo-electric sorting apparatus. GUNSON (SEEDS) Ltd., R. R. Dec. 11, 1958 [Oct. 20, 1958], No. 33485/58. Class 40(3). In an apparatus for sorting articles according to colour the articles are radiated by light and viewed against backgrounds by a plurality of photo-electric means which receive light from the articles and the backgrounds from a corresponding number of different directions. The backgrounds are so supported that their positions may be simultaneously adjusted. The photo-electric outputs control means for separating desired from uridesired objects. Each photo-electric means may be sensitive either to light of one colour only or to light in two distinct parts of the spectrum. The light may be polarized and infra-red may be used to. detect the presence of an article in the inspection area. When inspecting an object by detection of light in two parts of the spectrum the apparatus of Fig. 1 is used. Objects 2 pass through the frame-- 3 from a conveyer 1 and light received from the objects passes through a lens system and slot 10 to photocells 4, 5 by way of light-conducting member 12 (see also Specification 885,287). Filters 6, 7 select the two parts of the spectrum. The photocells feed a difference amplifier 14 which in turn feeds a comparator 15 which distinguishes desired from undesired objects (see Specification 885,287) and controls an ejector 16, e.g. an air jet device, Fig. 7 (not shown),, which ejects faulty articles. The frame 3, Fig. 2, comprises a square inspection area through which fall the objects 2, the objects being illuminated by indirect visible light from lamps 25-28, and, via filters 21, by infra-red. Coloured interchangeable backgrounds 22 are supported on carriers and shielded by shields 24 from direct light from adjacent lamps. The backgrounds and carriers are all linked together so that by movement of arm 31 the distance of each background from the object 2 may be varied so that the intensity of the reflection is also varied. Alternatively, each background comprises a cylinder rotatably mounted on a shaft, the cylinder being coloured in different areas with varying amounts of the colours in which sorting is to take place. If the objects to be sorted show a high degree of specular reflection they are irradiated with polarised light, Fig. 4 (not shown), and only diffuse light from the objects is detected by the photo-cell system, (see Specification 885,266). Specification 885,285 also is referred to.