Hot-gas engine

Claim 1

In a hot-gas engine having one variable-volume compression space and one variable-volume expansion space in communication and respectively operable at lower and higher average temperatures, and communicating between said compression and expansion spaces a cooler, a regenerator, and a heater heated by a heating medium and through which flows a working medium, the heater comprising a plurality of first pipes positioned generally parallel to define a cylinder, these pipes having near ends in communication with the regenerator and remote ends, a plurality of second pipes each positioned generally parallel to and between two of said first pipes, the second pipes having remote ends in communication with the remote ends of said first pipes, and having near ends bent inwardly of said cylinder, communicating with said expansion space, and defining an annular space between said near ends of said first and second pipes, the heater further comprising a plurality of elements positioned generally in said annular space and spaced from the near ends of said first and second pipes each element separating the near ends of two adjacent first and second pipes and defining a flow duct therebetween for increasing the flow of said heating medium in said ducts.