Double-acting modular free-piston stirling machines without buffer spaces
OwnerDavid Ray Gedeoninventor
Life of this patent
Estimating the term…
Abstract
Multiple free-piston stirling-cycle machine modules are connected together in double-acting configurations that may be used as engines or heat pumps and scaled to any power level by varying the number of modules. Reciprocating piston assemblies oriented in balanced pairs reduce vibration forces. There are no buffer spaces. Linear motors or generators are packaged inside piston cavities entirely within the module working spaces. The external heat-accepting and heat-rejecting surfaces in one embodiment are directed along inward-facing and outward facing cylinders, and in another embodiment along parallel planes, simplifying thermal connections to the external heat source and sink.
Claims13
A free-piston double-acting Stirling-cycle machine comprising a plurality of interconnected modules, each module comprising:
- a. a cylindrical piston assembly moving back and forth axially within a cylindrical side wall of an enclosing housing, providing both compression and expansion within a Stirling-cycle working space,
- b. an electromechanical transducer operatively connected to said piston assembly and disposed within the Stirling-cycle working space, and
- c. said piston assembly comprising a piston body and a piston shell, where said piston body includes a transducer cavity at one end configured to enclose one or more elements of said electromechanical transducer.
An electromechanical transducer for converting electrical current to mechanical force or mechanical motion to electrical voltage, comprising:
- (a) an electrical coil carrying electrical current wound around the outside of an inner bobbin, comprising a spool-shaped cylindrical core of soft ferromagnetic material,
- (b) a radially polarized permanent magnet located radially outside said bobbin and affixed to the inner wall of an axially moving piston body such that magnetic flux is directed in alternating axial directions through the central core of said bobbin as said piston body moves axially back and forth,
- (c) an outer cylinder of soft ferromagnetic material located immediately outside the outer wall of said axially moving piston body, serving as a magnetic flux return path and also serving to guide said piston body, and
- (d) mechanical forces applied between said bobbin and said piston body and electrical connections made to the end terminals of said electrical coil.
Dependencies are inferred from the claim text.