the filtering material being supported by at least two pervious coaxial walls

Full Title

Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof (B01D27/02 takes precedence) > with the filter bed stationary during the filtration > the filtering material being clamped between pervious fixed walls (B01D24/10, B01D24/20 take precedence) > the filtering material being supported by at least two pervious coaxial walls