Watkins, Dunbar & Pollick
Heat transfer apparatus for heat pumps
 A refrigeration and heating system has been made in which improved efficiencies are obtained by placing helical concentric coils of at least two generators and recuperators on a common axis with a heating unit at the center and allowing the hot combustion gases to circulate in serpentine fashion through separate concentric chambers containing the coils. Further efficiencies are obtained by placing an absorber, condenser and recuperator with a single module and by using tube-in-tube or tube-in-cylinder construction with fluted inner tubes. 
Columbia Gas System Service Corporation
F F Y Y F F
F28D F25B Y02A Y02B F28F F25B
inventional inventional additional additional additional inventional
Howard C. Richard N. Kevin R. F. Bert Stephen E.
Meacham, Jr. Christensen McGahey Cook Petty