Abstract: A casing preferably formed of sheet metal deep drawn and seamless has an outlet at its bottom and an inlet in its cylindrical side wall below its open top a portion of which is circumferentially indented providing an inwardly projecting shoulder below said inlet, and a cover is removably clamped on said open top of the casing and has an extension engaging and holding a circumferential projection on a filter element in liquid-tight contact with said shoulder. The extension has perforations providing for passing of liquid from said inlet into said filter element, and may have an imperforate portion to extend into the liquid in said casing below said circumferential shoulder when the cover is closed during filtering operations so the liquid level will drop below the upper end of the filter element when the cover is removed and thus prevent spilling of the liquid.