Claims
- 1. Isothermal positive displacement machinery having a variable volume compression-expansion chamber defined in part by an outer round flexible metal bellows-like wall having a plurality of convolutions and in further part by an end wall that is adapted to reciprocate along the axis of the outer bellows-like wall characterized in that the convolutions of the outer wall are joined in close axial spacing along inner and outer circular boundaries, the inner boundary of each convolution of the outer wall has a diameter of from about one-third to about one-tenth that of the outer boundary, and the inner boundaries of the convolutions define a zone connecting the small volumes defined between adjacent convolutions, the zone being small and in close diffusive thermal contact with the bellows-like wall to ensure that the working gas remains isothermal throughout each cycle, that during each stroke numerous heat exchanges occur between the working gas in the chamber and the bellows-like wall by both laminar and turbulent heat transfer and that heat is conducted to and through the bellows-like wall and to and from a thermal reservoir externally of the bellow-like wall.
- 2. Isothermal positive displacement machinery according to claim 1 and further characterized in that there is an inner round flexible metal bellows-like wall nested within the outer wall and defining an annular chamber, the inner wall has a plurality of convolutions joined in close axial spacing along inner and outer circular boundaries, and the nearer boundaries of the inner and outer walls are closely spaced radially and define as annular zone connecting the small volumes between adjacent convolutions of both the inner and outer walls such that the chamber is substantially free of trapped volumes that are not in close diffusive turbulent thermal contact with one of the bellows-like walls, thereby ensuring that the working gas remains isothermal throughout the cycle.
- 3. Isothermal positive displacement machinery according to claim 1 in which the chamber is defined transversely solely by the outer wall and further characterized in that the diameter of the inner boundary is from about one-fifth to about one-tenth of the diameter of the outer boundary.
- 4. Isothermal positive displacement machinery according to claim 1 in which the chamber is defined transversely solely by the outer wall and further characterized in that the diameter of the inner boundary is from about one-third to about two-thirds of the diameter of the outer boundary, and a metal baffle is connected to the bellows-like outer wall within each convolution, each baffle having holes to cause circulation of the working gas within the chamber for enhancement of the heat transfer between the gas and the baffles and bellows-like wall.
- 5. Isothermal positive displacement machinery according to any of claims 1 to 4 and further characterized in that each bellows-like wall comprises annular discs joined and sealed at each inner and outer boundary to an adjacent disc.
- 6. Isothermal positive displacement machinery according to any of claims 1 to 3 and further characterized in that a fluid is caused to flow through said external thermal reservoir and over the surface of the bellows-like wall externally of the chamber for enhancement of the heat transfer from the working gas to and through the bellows-like walls.
- 7. Isothermal positive displacement machinery according to any of claims 1 to 3 and further characterized in that the configurations of the bellows-like wall convolutions are such that no working gas in the chamber is ever farther than 10 mm. from a bellows-like wall surface.
- 8. Isothermal positive displacement machinery according to claim 4 and further characterized in that the configurations of the bellows-like wall convolutions and the baffles are such that no working gas in the chamber is ever farther than 10 mm. from a wall or baffle surface.
- 9. Isothermal positive displacement machinery according to claim 5 and further characterized in that each disc of the bellows-like walls has not less than five ripples for reduced wall stress and enhancement of heat transfer between the working gas and said walls.
- 10. Isothermal positive displacement machinery according to any of claims 1 to 3 and further characterized in that the ratio of the surface area of the bellows-like or walls to the surface area of a right circular cylinder of equivalent volume is not less than about 10:1.
- 11. Isothermal positive displacement machinery according to claim 4 and further characterized in that the ratio of the total surface area of the bellows-like walls and the baffles to the surface area of a right circular cylinder of equivalent volume is not less than about 10:1.
- 12. Isothermal positive displacement machinery according to any of claims 1 to 4 and further characterized in that the heat mass of the thermal skin depth of each bellows-like wall is not less than about 100 times the heat mass of the working gas.
- 13. Isothermal positive displacement machinery according to any of claims 1 to 4 and further characterized in that the compression ratio of the machinery is of the order of from 2.0:1 to 2.7:1.
- 14. Isothermal positive displacement machinery according to any of claims 1 to 4, the machinery having a Stirling cycle unit composed of a compression chamber and an expansion chamber as claimed in any of claims 1 to 4, the chambers being closely coupled to each other for gas transfer by a regenerator positioned between them and having movable end walls driven harmonically at a phase relationship of from about 90.degree. to 120.degree., and characterized in that the lengths, areas and shapes of the gas flow paths of the regenerators are such that the gas flow friction loss of the regenerator does not exceed about 3%.
- 15. Isothermal positive displacement machinery according to claim 14 and further characterized in that the dead volume of the regenerator and all connecting volumes between the chambers and the regenerator are less than about 10% of the displacement volume of the unit.
- 16. Isothermal positive displacement machinery according to claim 14 and further characterized in that the regenerator is designed to have from about 5 to about 10 heat exchange lengths.
- 17. Isothermal positive displacement machinery according to claim 14 and further characterized in that the heat mass of the metal of the regenerator is of the order of 10 to 20 times the heat mass of the working gas.
- 18. Isothermal positive displacement machinery according to claim 14 and further characterized in that the movable end walls of the chambers are driven by a free piston positive displacement engine that operates on an Otto or diesel cycle.
- 19. Isothermal positive displacement machinery according to claim 14 and further characterized in that the movable end walls of the chambers are driven by a linear electric motor.
- 20. Isothermal positive displacement machinery according to claim 14 and further characterized in that there is a second Stirling cycle unit composed of a compression chamber and an expansion chamber, each having a bellows-like peripheral wall and being closely coupled to each other for gas transfer by a regenerator positioned between them, the expansion chambers and the compression chambers, respectively, of the two units being mechanically interconnected to move conjointly.
- 21. Isothermal positive displacement machinery according to claim 14 and further characterized in that there is a Stirling cycle engine composed of a compression chamber and an expansion chamber as claimed in any of claims 1 to 4 closely coupled to each other for gas transfer by a regenerator positioned between them, and the expansion chambers and the compression chambers, respectively, of the unit and the engine being mechanically coupled to move conjointly, and in that there is means for supplying a flow of a hot gas to the thermal reservoir of the expansion chamber of the engine.
- 22. Isothermal positive displacement machinery according to claim 14 and further characterized in that there is means for supplying a flow of hot gas to the thermal reservoir of the expansion chamber, whereby the unit is a Stirling cycle engine.
- 23. Isothermal positive displacement machinery according to any of claims 1 to 4 and further characterized in that there is means for driving one end wall of the chamber, and in that the other end wall of the chamber has valved supply and exhaust ports for admitting and releasing gas to and from the chamber whereby the machinery is a compressor.
- 24. Isothermal positive displacement machinery according to claim 5 and further characterized in that each disc is joined and sealed by an elastomer adhesive at its inner and outer boundary to an adjacent disc.
- 25. Isothermal positive displacement machinery according to claim 24 and further characterized in that pairs of adjacent discs are joined at their outer boundaries by crimped channels.
Parent Case Info
This application is a continuation-in-part of U.S. patent application Ser. No. 302,254, filed Sept. 14, 1981 now abandoned.
US Referenced Citations (4)
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
302254 |
Sep 1981 |
|