The text and illustrations of US patents published before March 1, 1989 are in the public domain unless the patent text contains a specific notice that portions are copyrighted. See 37 CFR 1.71(d), 37 CFR 1.84(s) The original patent contains no such notice, so its contents are in the public domain. Note: This only applies to images published before March 1, 1989. Patents published after that date are most likely copyrighted, unless in the public domain for another reason, such as {{PD-ineligible}}.

Phases:

1. Isothermal compression
2. Isobaric expansion
3. Isothermal expansion
4. Isobaric compression

Figures:

• FIG. 1 is a longitudinal section of a hot gas engine according to the invention.
• FIG. 2 is a cross section of the hot gas engine taken on the line ‘II--II in FIG. 1. '
• FIG. 3 is a longitudinal section of chamber e in FIG. 2.
• FIG. 4 is a longitudinal section of the chamber g in FIG. 2.
• FIG. 5 is a longitudinal section of the chamber i in FIG. 2.
• FIG. 6 is a longitudinal section of the pipe loops constituting the heat exchanger.
• FIG. 7 is a partial view of the pipe loop arrangement.
• FIG. 8 is a longitudinal section of a pipe loop having an enlarged heat transfer surface.
• FIG. 9 is a cross section of a heat transfer element.
• FIG. 10 is a longitudinal section of a heat transfer element.

Parts:

• 1 housing
• 2 rotor
• 3 rotor
• 4 housing section
• 5 housing section
• 6 shaft
• 7 shaft
• 8 piston (of rotor 3)
• 9 recesse
• 10 recesse
• 11 outer wall
• 12 outer wall
• 13 annular working chamber
• 14 spherical body
• 15 pipe(s) / pipe loops
• 16 inner portion
• 17 outer portion
• 18 inlet ports
• 19 outlet ports
• 20 compression stage
• 21 expansion stage