The performance of filters under hot dynamic conditions

A test facility has been constructed which enables filters to be tested at their full rated air-flow at temperatures up to 5500C. Initial test results suggest that filters as presently designed and constructed are not satisfactory where differential pressures in excess of 1600 Pa at a temperature of 5000C are likely to occur. Recent tests have shown that by careful attention to detail design this limiting differential pressure can be raised to 2200 Pa at 5000C. This higher limit is a function of the inherent properties of the filter media used. Measurements show that the tensile strength of the media is reduced from typically 0.4 KN/m to 0.05 KN/m across the pleat fold after the high temperature test. Initial tests on filters produced from a newly developed glass fibre media incorporating a glass fibre support scrim indicate that the filter maintains an efficiency in excess of 99.9% after exposure to differential pressures of 7500 Pa at 5000C. (author)