GB712113A - Improvements in or relating to sorting apparatus - Google Patents

Abstract

712,113. Sorting photo-electrically. BAIGENT, G. M. July 21, 1952 [July 19, 1951], No. 17195/51. Class 40 (3) Objects to be sorted are examined by means of light rods which direct light from various parts of the object under inspection on to a single sensitive device. In the sorting device shown falling objects are guided by discs 8, 9 through a central transparent tube 11 mounted in a cylindrical holder 1. Situated between the holder interior and discs 8, 9 are a pair of gas discharge tubes 14, 15 which illuminate the object. Light from these sources is reflected either from an object in tube 10 or from a comparison background 2 to one of three holders 22 spaced around cylinder 1. Each disc houses a lens 5 focusing light through an aperture 6 on to a horizontal slit in a diaphragm through the central cylinder. The light passes through the slit to a rod 21, one end of which is fixed in holder 22 and all three rods are so bent as to direct light on to a single mixing block 25 which diffuses it evenly over the sensitive surface of a photo-electric cell 24. Shields 16, 17 prevent light reaching lenses 5 direct from the discharge tubes. The light rod may be glass or polymethyl methacrylate polished or silvered, internally polished opaque tubes or glass tubes polished either externally or internally. The viewing assemblies may be so mounted as to view the leading or trailing edges of a falling object. Objects of a particular colour may be sorted by using coloured rods or filters. The amount of light passing through a particular rod may be varied by means of a variable shutter on the end of the rod or by making the rods of two relatively movable parts. Specification 492,035 is referred to.