Abstract: An assembly including an engine component, such as a fuel injector, seated against a seating surface of a cylinder head is provided with a positive seal contact an uppermost point of contact between an injector sleeve and a seating surface of the cylinder head. The positive seal contact prevents coolant from the water jacket from travelling below the uppermost point of contact, thereby avoiding cavitation damage which might otherwise occur by the entrapment of liquid between the cylinder head seating surface and the injector sleeve. In an embodiment, a raised annular ridge is formed in the seating surface of the cylinder head at the location of the uppermost point of contact. This ridge becomes embedded in the injector sleeve. Also, in an embodiment, the cylinder head includes a circular recess upwardly from the uppermost point of contact.

Abstract: A fluidized catalytic cracking process and apparatus with an active bed annular spent catalyst stripper is disclosed. An annular catalyst stripper disposed about a riser reactor is separated, by a baffle or fluid flow, into a secondary stripper nearer the catalyst regenerator and a primary stripper on the far side of the annular stripper from the regenerator. Catalyst flows through the primary stripper as a dense bed, to a transport means which lifts catalyst to the inlet of the secondary stripper. The "dead" region on side of annular strippers far from the regenerator is eliminated. Preferably catalyst is added to the primary stripper via cyclone diplegs, and a cyclone is used on the transport outlet.