A filter device has a frame, a grid, a filter medium and, if desired, a gas adsorption medium. The frame is flexible so as to be temporarily deformable and is made of polypropylene, as is the grid. The filter medium is a mat of non-woven material and the gas adsorption medium is activated carbon....http://www.google.com.au/patents/US6228152?utm_source=gb-gplus-sharePatent US6228152 - Filtering device for equipping a ventilation and/or heating and/or air conditioning unit, more particularly for a motor vehicle
