Abstract: A filtering vessel adapted to accommodate a filter bag for filtering a liquid under pressure. The vessel comprises a top open cylindrical housing having a sidewall and a bottom with an outlet port, and a basket supported within the housing to retain the filter bag therein. A jacket is formed to surround a top portion of the housing to form therebetween an annular fluid passage which is open at its upper end and communicates with an inlet port formed at the jacket for coupling a pressurized liquid supply line. Also included in the vessel is a top cover detachably mounted on the housing and the jacket to close the top opening of the housing as well as that of the annular fluid passage. The top cover is formed in its lower surface with peripheral openings and a center opening which are intercommunicated within the top cover.