| 摘要 |
954,717. Photo-electric inspection devices. HENRY SIMON Ltd. March 14,1963 [March 28, 1962], No. 11833/62. Heading G1A. The invention relates to apparatus for monitoring dry fluent material as to its colour and granularity. The proposed apparatus may be used with flour, salt, starch, hydrated lime and like materials. In it an auger 5 is driven to separate from the main flow of material along a main trunking 2 a proportion fed to a sample chamber 1 having a transparent window 6. A valve 7 with a counterweight 8 maintains the material passing through the sample holder in a uniform state of consolidation. The monitoring is done by comparing the diffuse reflectivity of the material in the sample holder 1 with that of a reference surface 14. For this purpose light from a lamp and reflector 12 is collimated at 11 and directed by rotating eccentrically mounted mirror 9 alternately towards the sample and the standard. Diffuse light from the sample reaches photo-cell 18 through adjustable shutter 23 and that from the sample through preset attenuator 27. A filter, preferably having maximum transmission over the 525 to 625 millimicron band, is placed immediately in front of the cell. Any difference in the light received by the cell over the two paths gives an A.C. error signal whose phase is compared with the output of a device coupled to mirror drive motor 13 and fed to a motor 22 which adjusts shutter 23 to reduce the error signal to zero. The position of the shutter, and thus the reflectivity of the sample, is indicated by pointer 24 and also recorded at 26. Limit switches 25 operate an audible or visible alarm if the material characteristics pass outside a predetermined acceptable range. |
