Norvell & Associates
Concentric insulating conduit
 A concentric insulating tubular conduit member for use in forming a conduit string, such as a tubing string in a subterranean well, is disclosed. Each individual concentric conduit comprises an outer tubing and an outwardly flared inner tubing welded to the outer tubing at the ends. Insulation may be contained within the sealed annular cavity between the inner and outer tubing members and between inner and outer coupling members at the juncture between adjacent tubing sections. Centralizers are positioned in the annular cavity between the inner and outer tubular members at one or more points between the ends of each conduit section. Each centralizer has an axially extending cylindrical section and a radial support section in contact with one of the tubular members. 
Baker Oil Tools, Inc.
F F
F16L F16L
inventional inventional
Yung J.
Kim