Image Number 2 for United States Patent #4771738.
A dual sleeve boiler is arranged to dispose a portion (72, 74, 76) of its fluid conduit between a support member (64) of the boiler and the heat generating portion (20, 24) of the boiler. The end of a conduit through which water is introduced to the boiler is disposed between an enclosing means (24) which forms an axial end of the boiler and a cylindrical tube (64) disposed through the center of the boiler for purposes of supporting the boiler. As relatively cool fluid is introduced into the conduit of the boiler, it passes between the heat generating portions (20) of the boiler and the support tube (64) and provides a thermal barrier to prevent heat from traveling, through conduction, into the supporting means (64) which is attached to an external support member (71). This prevents heat from flowing into the external support member (71) and possibly damaging heat sensitive components attached thereto.