Westshore Terminals Ltd at Joseph’s Bank, Vancouver installed a Control Systems Technology P/L (CST) precision shiploading belt weigher in October 1998 which has laid a good foundation for further sales to shiploading facilities around the world. At Westshore the main conveyor moves up to 7,700 mtph of coal at 4.5m/s on a 2133mm belt toughed at 45 degrees. CST provided a large weigh frame based on large universal beam side members, six idlers in length with calculated accuracy of better than 0.25% over a range from 20% to 120% of flow.
The results, without any calibration adjustments to bring average error to zero, are outstanding with performance never being more than 1% from draft survey (in fact the largest error is 0.83%). The typical error is less than 0.5% and the average error is 0.03%! These results were a direct result of dead weight calibration without any adjustments, “factoring” or “live load” adjustments.
There has long been debate over the accuracy of draft survey figures according to CST’s managing director, Ian Burrell. His experience indicates that draft survey can’t be expected to be any better than +/- 1.0%. In this case, errors are so small as to increase one’s confidence in draft survey.
Ian Burrell said all customers wanted belt weighing systems they could rely on and were prepared to pay more for systems which produce dependable data. “It is not that CST want to charge more than their competitors but that CST want to give customers more belt weigher,” he said. “CST systems invariably include a more robust and longer weigh frame which is better able to discriminate the live material signal from belt tension effects.”
CST is a private, locally owned manufacturer in Peakhurst NSW which is ISO 9001:2000 certified, and manufactures a full range of belt weighing and weighfeeder equipment to the bulk materials handling industry. CST belt weighers are ANSC Pattern Approved for trade purposes No.6/14D/113.
Australian Bulk Handling Review – April/May 1999