Abstract: Herein disclosed is a dual-tube heat pipe type heat exchanger comprising a heat pipe confined with a working fluid for transferring a heat as a latent heat by repeating evaporations and condensations. The heat pipe includes an outer tube which is disposed within a hot fluid such that its axis is generally horizontal. Further included is an inner tube which is inserted in the outer tube and radially offset upward to substantially contact with the top portion of the inner face of the outer tube and to confine a space between the inner circumference of the outer tube and the outer circumference of the inner tube, thus forming the heat pipe.

Abstract: Herein disclosed is a heat pipe type heat exchanger which comprises: a container for containing a first heating medium therein or causing the same to flow therethrough; at least one heat pipe extending liquid-tight with a substantially horizontal axis through the container; and a tube extending gas-tight and axially through the heat pipe for causing a second heating medium to flow therethrough, whereby the heat exchange is effected between the first and second heating mediums through the walls of the heat pipe and the tube. In case a plurality of heat pipes are provided, the individual tubes extending axially through the corresponding heat pipes are connected at their ends to each other by means of bends such that they make a zigzag or meandering piping. This retains a wide heat exchanging area.