| 摘要 |
<p>1,158,899. Photo-electric fault detection. BELOIT CORP. Nov. 15, 1966 [Jan. 5, 1966], No.51089/66. Heading G1A. Defects in a travelling web of paper 11 are detected photo-electrically before sections of the web having defects reach coating apparatus 12, 13, so that the latter may be deactivated to allow the faulty sections to pass through uncoated and thereby prevent fouling of the coating apparatus and breaking of the web. In one arrangement, Fig. 1 holes and relatively thin parts of the web are detected by photo-electric inspection apparatus 16, 17 which may comprise a single light source-detector combination or an array of these. If the intensity transmitted by the web is above the level set in automatically- or manually-adjustable means 20, indicating the presence of a fault, relay 18 is actuated to activate sequencing device 21. This causes: marking of the defective web section (via control 23); disengagement of coating rollers from the web or lowering of the pans of coating fluid in coaters 12, 13 (via control 24); and disengagement of the coater wiper blades (via control 25). Also a timer or footage control 26 is started. The defective portion of web is allowed to pass through the coaters uncoated, and after a predetermined time set into control 26, a second sequencing device 29 is activated and the timer 26 stopped and reset. The device 29 controls reactivation of the coating apparatus by reengagement of rollers, wipers &c., and resetting of relay 18. In a modification, Fig. 2 (not shown), defects are detected as instantaneous variations of mass per unit area from an average value of transmitted light. Variations above a pre-set value control deactivation of the coaters for a pre-set time which can be adjusted. Parts of this control system are described in more detail i.e. the device which compares the variation level with a predetermined value, Fig. 3 (not shown); the deactivation sequencing device, Fig. 4 (not shown); and the device for producing a signal representative of the instantaneous variation from the average value, Fig. 5 (not shown).</p> |
