Rotary positive displacement engine

1. A rotary positive displacement expander comprising:

a) a housing having at least first and second intersecting cylindrical bores disposed therein;

b) at least one power rotor mounted for rotation within said first cylindrical bore, said power rotor having a cylindrical outer surface of a diameter less than that of said cylindrical bore and at least one vane extending from the cylindrical outer surface of the power rotor to close proximity to the walls of the cylindrical bore;

c) an annular barrier rotor having cylindrical inner and outer surfaces and mounted for rotation within said second cylindrical bore within said housing, at least one port means extending between the inner and outer surfaces of the barrier rotor, the outer cylindrical surface of the barrier rotor being positioned in close proximity to the outer cylindrical surface of the power rotor;

d) external port means for fluid communication with the port means of said barrier rotor, said external port means communicating the powering charge to the barrier rotor; and

e) the position of the axis of rotation of the barrier rotor being adjustable with respect to the axis of rotation of the power rotor, such that the clearance between the outer cylindrical surface of the power rotor and the outer cylindrical surface of the barrier rotor may be adjusted.

2. The rotary positive displacement expander as claimed in claim 1 when the external port means include a stator located within said annular barrier rotor, said stator having ports for fluid communication with the port means of said barrier rotor when said port means of the stator and barrier rotor are aligned at predetermined rotary positions of said barrier rotor.

3. The rotary positive displacement expander as claimed in claim 1 further including abradeable seals disposed between the outer cylindrical surface of the barrier rotor and the cylindrical bore in which the barrier rotor rotates.

4. The rotary positive displacement expander as claimed in claim 2 further including abradeable seals disposed between the inner cylindrical surface of the barrier rotor and the stator.

5. The rotary positive displacement expander as claimed in claim 1 further including exhaust ports disposed within the cylindrical bore in which the power rotor rotates.

6. The rotary positive displacement expander as claimed in claim 1 wherein the barrier rotor is mounted for rotation within said second cylindrical bore by means of a sub-housing adjustably mounted to the expander housing.

7. The rotary positive displacement expander as claimed in claim 6 wherein the sub-housing is mounted to the expander housing by means of fasteners carried in elongated slots to permit the location of the sub-housing to be adjusted with respect to the expander housing so as to thereby adjust the position of the barrier rotor.

8. The rotary positive displacement expander as claimed in claim 1 further including a third cylindrical bore disposed in said housing and a second power rotor mounted for rotation within said third cylindrical bore, said power rotor having a cylindrical outer surface of a diameter less than that of said third cylindrical bore and at least one vane extending from the cylindrical outer surface of the second power rotor to close proximity to the walls of the third cylindrical bore, the outer cylindrical surface of the second power rotor being positioned in close proximity to the outer cylindrical surface of the barrier rotor.

9. The rotary positive displacement expander as claimed in claim 1 wherein the power rotor includes two vanes located 180.degree. apart on the outer cylindrical surface.

10. A rotary positive displacement expander comprising:

a) a housing having at least first and second intersecting cylindrical bores disposed therein;

b) at least one power rotor mounted for rotation within said first cylindrical bore, said power rotor having a cylindrical outer surface of a diameter less than that of said cylindrical bore and first and second opposed vanes extending from the cylindrical outer surface of the power rotor to close proximity to the walls of the cylindrical bore;

c) an annular barrier rotor having cylindrical inner and outer surfaces and mounted for rotation within said second cylindrical bore within said housing, at least one port means extending between the inner and outer surfaces of the barrier rotor, the outer cylindrical surface of the barrier rotor being positioned in close proximity to the outer cylindrical surface of the power rotor;

d) a stator located within the annular barrier rotor, said stator having port means for fluid communication with the port means of said barrier rotor when said port means of the stator and barrier rotor are aligned at predetermined rotary positions of said barrier rotor.

11. The rotary positive displacement expander as claimed in claim 10 further including a third cylindrical bore disposed in said housing and a second power rotor mounted for rotation within said third cylindrical bore, said power rotor having a cylindrical outer surface of a diameter less than that of said third cylindrical bore and at least one vane extending from the cylindrical outer surface of the second power rotor to close proximity to the walls of the third cylindrical bore, the outer cylindrical surface of the second power rotor being positioned in close proximity to the outer cylindrical surface of the barrier rotor.

12. The rotary positive displacement expander as claimed in claim 10 wherein

the position of the axis of rotation of the barrier rotor is adjustable with respect to the axis of rotation of the power rotor, such that the clearance between the outer cylindrical surface of the power rotor and the outer cylindrical surface of the barrier rotor may be adjusted.

13. The rotary positive displacement expander as claimed in claim 12 wherein the barrier rotor is mounted for rotation within said second cylindrical bore by means of a sub-housing adjustably mounted to the expander housing.

14. The rotary positive displacement expander as claimed in claim 13 wherein the sub-housing is mounted to the expander housing by means of fasteners carried in elongated slots to permit the location of the sub-housing to be adjusted with respect to the expander housing so as to thereby adjust the position of the barrier rotor.

15. The rotary positive displacement expander as claimed in claim 10 further including abradeable seals disposed between the outer cylindrical surface of the barrier rotor and the cylindrical bore in which the barrier rotor rotates.

16. A rotary positive displacement engine, for powering from an external source of pressurized gas, comprising:

a) a housing having at least first, second and third intersecting cylindrical bores disposed therein;

b) a first and a second power rotor mounted for rotation within said respective first and second cylindrical bores, each of said power rotors having a cylindrical outer surface of a diameter less than that of their respective cylindrical bore and first and second opposed vanes extending from the cylindrical outer surfaces of the power rotors to close proximity to the walls of the cylindrical bore in which the power rotor is mounted;

c) an annular barrier rotor having cylindrical inner and outer surfaces and mounted for rotation within said third cylindrical bore within said housing, first and second port means extending between the inner and outer surfaces of the barrier rotor, the outer cylindrical surface of the barrier rotor being positioned in close proximity to the outer cylindrical surfaces of the first and second power rotors;

d) a stator located within the annular barrier rotor, said stator having port means for fluid communication with the port means of said barrier rotor when said port means of the stator and barrier rotor are aligned at predetermined rotary positions of said barrier rotors.

17. The rotary positive displacement engine as claimed in claim 16 wherein the position of the axis of rotation of the barrier rotor is adjustable with respect to the axes of rotation of the power rotors, such that the clearance between the outer cylindrical surfaces of the power rotors and the outer cylindrical surface of the barrier rotor may be adjusted.

18. The rotary positive displacement engine as claimed in claim 16 wherein the powering gas comprises steam.

19. The rotary positive displacement engine as claimed in claim 16 wherein the first and second power rotors and the barrier rotor are coupled together for synchronous rotation.

20. The rotary positive displacement expander as claimed in claim 16 further including abradeable seals disposed between the outer cylindrical surface of the barrier rotor and the cylindrical bore in which the barrier rotor rotates.