Automatic system for improving performance of biological gas filters - where filter medium moisture content is controlled by continuously measuring and adjusting bulk density and temp.

摘要

Procedure restricts the effect of negative operating conditions, weather etc. on a biological gas filter. Moisture content of the filter medium is supervised by continuously measuring its bulk density and is controlled by switching on or off a gas flow moistening device (1), a filtrate spray system (2), or a bypass (3) for directly aspirating a clean un-cooled gas flow, if the bulk density reaches a limiting value. Auxiliary control of the moisture content is achieved by a system which measures the temp. difference between the filter medium and the gas stream. If the filter medium temp. becomes undesirably high, the gas flow moistening device is switched on, and if it becomes undesirably low an un-cooled gas stream is directly aspirated. USE/ADVANTAGE - Used in extract systems for the treatment of gases before discharging to the atmos.. Biological filters are used for reliably breaking down complex odour emissions in the gas stream. Maintains optimum moisture content in the filter medium, since too low a moisture content leads to reduction in mechanical and biological filtration effect and to the emission of odours, while too high a moisture content leads to rotting and solidification of the filter medium.