METHOD AND APPARATUS FOR THE COMBINED USE OF DUAL DENSITY MEASUREMENTS TO ACHIEVE A FAST AND ACCURATE DENSITY MEASUREMENT IN PNEUMATICALLY TRANSPORTED SOLIDS

摘要

The suspension density of a pneumatically transported solid,such as coal, is obtained by using a combination of a radial gammaray densitometer and a second, fast-response density metre. Thecombination is required to get the desired combination of accuracyand response time. The second measurement is used for its fastresponse time and may be used to control operating conditions of agasifier. The slower, but more accurate, radial radiation measurementis used to recalibrate the second measurement approximatelyevery 10 seconds and correct for drift thereof. The drift in thesecond measurement is sufficiently slow that high accuracy can bemaintained by the recalibration technique.