Cooker extractor hood filter mat - with colour change of fat soluble painted pattern indicating required replacement

摘要

A filter mat for a cooker extractor hood, made for example of a fibre mixt. contg. 40% viscose rayon, 25% polyacrylonitrile and 35% cellulose, is partly coated at the inflow side with a mixt. of two mutually insoluble components, one of which has a colour which is clearly distinct from that of the fibre mixt., and is soluble by fat and/or oil. The other component is not soluble in fat and/or oil If the mixt. is distributed as points or a pattern of lines of 0.5-2mm width, it becomes visible whether fat accumulation had produced a colour change. This indicates that the filter mat should be replaced.