Rotary machine
A rotary machine, for directing a quantity of fluid from an inlet to an outlet, comprises one or more elliptical or near-elliptical rotors having planetary rotation within a housing. The interior cavity of the housing comprises an inverse apex region that is in contact with the rotor during its rotation. In various embodiments the rotor and housing can be symmetric or asymmetric in cross-section. Features are described that can improve the operation of the machine for various end-use applications. Such features include cut-outs that are fluidly connected to the inlet or outlet ports of the machine, mechanisms for reducing variation in output flow rate from the rotary machine, linings for the interior cavity of the housing, pressure relief mechanisms, dynamic apex seals and other sealing mechanisms.
1. A rotary machine comprising:
(a) a rotor comprising an outer surface having an elliptical cross-section;
(b) a crankshaft for providing rotational force to rotate said rotor about a first axis of rotation at a first angular velocity;
(c) a mechanical coupling between said crankshaft and said rotor, said mechanical coupling configured such that:
(i) rotation of said crankshaft about said first axis of rotation induces rotation of said rotor about an instantaneous second axis of rotation at a second angular velocity proportional to said first angular velocity, said instantaneous second axis of rotation positioned at a fixed distance from said first axis of rotation; and
(ii) said instantaneous second axis of rotation orbits about said first axis of rotation at said first angular velocity;
(d) a drive assembly, wherein said drive assembly is connected to said crankshaft for rotating said crankshaft at a rotational rate that varies during a period of each rotation of said crankshaft;
(e) a housing having an inlet and an outlet formed therein, said housing having an interior cavity within which said rotor is configured to rotate, said housing interior cavity comprising an inner surface having a cross-sectional profile defined by a locus of a set of points on said rotor outer surface for which an instantaneous velocity vector is perpendicular to a line drawn from a member of said set of points to said instantaneous second axis of rotation as said rotor completes one revolution of rotation, said inner surface of the housing interior cavity having an interiorly-extending inverse apex region between said inlet and said outlet that is in contact with said rotor during rotation of said rotor thereby providing separation between said inlet and said outlet;
wherein said inner surface of the housing interior cavity further comprises a first cut-out formed therein that extends circumferentially and is fluidly connected to one of said inlet or said outlet;
whereby, upon connecting said inlet to a fluid source, rotation of said rotor draws fluid into a space formed between said rotor and said inner surface of the housing interior cavity and discharges said fluid from said outlet.
2. The rotary machine of claim 1 , wherein said crankshaft induces rotation of said rotor about said second axis of rotation at a second angular velocity that is half said first angular velocity.
3. The rotary machine of claim 1 , wherein said first cut-out is connected to said inner surface of the housing interior cavity by a transition region.
4. The rotary machine of claim 1 wherein said first cut-out is fluidly connected to said inlet, and said first cut-out is configured to increase an amount of the fluid drawn via said inlet into said space formed between said rotor and said inner surface of the housing interior cavity during rotation of said rotor.
5. The rotary machine of claim 1 , wherein said first cut-out is fluidly connected to said inlet, and said inner surface of the housing inner cavity further comprises a second cut-out formed therein that extends circumferentially and is fluidly connected to said outlet.
6. The rotary machine of claim 5 wherein said second cut-out is configured to reduce mechanical restraint of said rotor during discharge of an incompressible fluid via said outlet.
7. The rotary machine of claim 1 , further comprising a second rotor comprising an outer surface having an elliptical cross-section, wherein said second rotor is configured to rotate out of phase with respect to said rotor.
8. The rotary machine of claim 1 wherein said drive assembly comprises a motor, a driveshaft and a universal joint.
9. The rotary machine of claim 8 wherein said driveshaft of said motor is configured to rotate at a substantially constant rate, and said universal joint is configured to provide a variation in the rotational rate of said crankshaft.
10. The rotary machine of claim 1 wherein said drive assembly comprises transmission comprising a non-circular gearing mechanism, said non-circular gearing mechanism configured to provide a variation in the rotational rate of said crankshaft.
11. The rotary machine of claim 1 wherein said inverse apex region comprises a dynamic apex seal.
12. The rotary machine of claim 1 wherein said rotary machine is a pump.
13. The rotary machine of claim 1 wherein said rotary machine is a compressor.