| 摘要 |
<p>1297483 Measuring moisture content electrically PEKAY MACHINE & ENG CO Ltd 19 April 1971 [21 Sept 1970] 26990/71 Heading G1N The moisture content of foundry sand on a conveyer belt is measured by measuring the resistance between at least two electrodes engaging in the sand, each electrode comprising an insulating housing with a plough nose, a conducting wheel protruding from the bottom of the housing and rotating in a vertical plane parallel to the direction of movement of the belt, means making an electrical wiping contact with the wheel or axle, and a scraper to remove any sand picked up by the wheel. As shown in Figs.1 and 2, each housing comprises a stack of insulating plates 38, 28, 26, 30, 40, plate 26 having a recess for the wheel and plates 28 and 30 for bronze bushings (32, 34), Fig. 5 (not shown), engaging a stub axle 54 for the wheel. Electrical connection to the wheel is by a screw 58 passing through plate 30 and into bushing 34. An edge scraper 92 and two side scrapers (74, 76), Fig.3 (not shown), are provided at the trailing edge of the wheel. The wheels may be rotated by electric motors 132, 136, Fig.6, or by frictional contact with the conveyer belt. The wheels are spaced in the direction of travel of the belt and staggered so that the rear wheel does not run in the groove left by the front wheel. The front housing may contain two wheels, Fig.8 (not shown). The electrodes are connected in a bridge circuit, the output of which may be used to control a moisture supplying device (not shown). The height of the wheels above the conveyer belt is adjustable by screws (143, 145), Fig.7 (not shown). The electrodes may be swung up out of the way, about pivots 128, 130. The apparatus may include a thermistor extending into the sand.</p> |
