French and Doescher
Heat exchanger
 In a shell and tube heat exchanger, cooperation between a shell and shroud within the shell is established by at least one boss extending radially outward from the exterior surface of the shroud and at least one channel on the inside of the shell. The channel has longitudinal and circumferential path portions which are adapted to receive the boss so as to allow for longitudinal and radial temperature expansion without incurring undesirable stresses on either the shell or the shroud. The shroud is disclosed as further including at least one longitudinally extending alignment guide which enables cooperation with guide rails associated with a tube bundle positioned within the shroud. 
Phillips Petroleum Company
Y Y Y F F F
Y10T Y10S Y10T F28D F28F F22B
additional additional additional inventional inventional inventional
William M. Cecil C.
Small Gentry