{HEAD ~ A heat exchange unit} 3 wherein {TAIL ~ said closed end hydride container} contains an essentially coaxial spring defining a central hydrogen gas space and confining metallic hydride former against the tube wall 
wherein
{ HEAD ~ A heat exchange unit } 3 wherein { TAIL ~ said closed end hydride container } contains an essentially coaxial spring defining a central hydrogen gas space and confining metallic hydride former against the tube wall
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH