to permit flow of gases or vapours other than upwardly through the fuel bed

Production of gases containing carbon monoxide and hydrogen, e.g. synthesis gas or town gas, from solid carbonaceous materials by partial oxidation processes involving oxygen or steam > Fixed-bed gasification of lump fuel > Apparatus; Plants > Arrangements or dispositions of valves or flues > to permit flow of gases or vapours other than upwardly through the fuel bed

Production of combustible gases containing carbon monoxide from solid carbonaceous fuels (destructive distillation processes C10B) > Fixed-bed gasification of lump fuel > Apparatus; Plants > Arrangements or dispositions of valves or flues > to permit flow of gases or vapours other than upwardly through the fuel bed