Filtering Materials and Filter Layers Made of Derivatives of Said Filtering Materials, Especially Raw and Refined Powders, Fibers and Granulates of Organic and Inorganic Origin and Mixtures of All Types of Said Substances, Mixtures of Said Raw Materials and Mixtures Thereof with Coal, Earth, Sand and Diatomaceous Earth; Felt, Vegetable Fibers, Synthetic Fibers, Linen, Paper and Cotton