Joint for connecting ceramic element to a tubesheet

A joint connecting a tubular ceramic element to a tubesheet, said joint comprising:

• a metallic internal seal housing having a first passageway communicating between opposite open ends thereof and configured to receive an open end portion of said tubular ceramic element such that said tubular ceramic element projects from one of the opposite open ends and an interior region of said tubular ceramic element is in flow communication with the other of the opposite open ends;
• said internal seal housing having an internal sealing surface defined in said first passageway and assembled in sections to allow said tubular ceramic element to be inserted into the internal seal housing with said open end portion of said tubular ceramic element adjacent said sealing surface;
• a ceramic to metal seal situated between said internal sealing surface and said open end portion of said tubular ceramic element to seal said first passageway and to hold said tubular ceramic element in place;
• a metallic external seal housing connected to an opening in said tubesheet and configured to hold said internal seal housing within a second passageway thereof, the second passageway being in flow communication with opposite sides of said tubesheet;
• and
• at least one metal-to-metal seal located within said second passageway and between said internal seal housing and an interior surface of said second passageway.