Claims
- 1. A centrifugal separator for separating components of a fluid comprising:an elongated separator bowl for receiving the fluid, said separator bowl being rotatable about an axis; an elongated shaft spindle disposed along said axis and partially extending into said separator bowl, said shaft spindle disposed for selective rotation and axial translation relative to said separator bowl; a variable speed motor coupled to said separator bowl for selectively rotating said separator bowl at a high separating speed and at a lower scraping speed; a clutch, disposed external to said separator bowl and proximate said shaft spindle, operative to enable rotation of said shaft spindle with said separator bowl at said separating speed when disengaged from said shaft spindle and to prevent rotation of said shaft spindle with said separator bowl at said scraping speed when engaged against said shaft spindle; a scraper assembly positioned within said separator bowl and coupled to an end of said shaft spindle, said scraper assembly including a plurality of scraper blades extending substantially to an interior surface of said separator bowl, said scraper blades having a scraping width in the direction of said axis substantially less than the length of said separator bowl in the direction of said axis; and a scraper actuator in communication with said clutch and said shaft spindle for selectively moving said clutch, said shaft spindle and said scraper assembly along said axis while said separator bowl is being rotated by said variable speed motor at said scraping speed for removing solids from the interior surface of said separator bowl.
- 2. The centrifugal separator according to claim 1, wherein the variable speed motor further comprises an electronic brake for stopping the rotation of said separator bowl.
- 3. The centrifugal separator according to claim 1, wherein said scraper assembly includes three or four scraper blades.
- 4. The centrifugal separator according to claim 1, wherein said separator bowl is a tubular bowl.
- 5. The centrifugal separator according to claim 4, wherein said tubular bowl comprises a small diameter in relation to a length thereof so that a ratio between the diameter and the length is at least 5/1.
- 6. The centrifugal separator according to claim 1, further comprising a residual liquid container movably positionable directly beneath and away from a discharge port of said separator bowl so that liquid drained from said separator bowl is collected when said residual liquid container is disposed directly beneath said discharge port.
- 7. The centrifugal separator according to claim 6, further comprising a solids receiving container disposable beneath said discharge port, whereby said residual liquid container may be disposed intermediate said discharge port and said solids receiving container, said residual liquid container being disposed away from said discharge port to allow solids to be received by said solids receiving container.
- 8. The centrifugal separator according to claim 1, wherein said scraper assembly comprises:a cylindrical hub; and a shaft spindle interface associated with said hub for receiving a shaft spindle, wherein said plurality of scraper blades extend radially and tangentially from points on the circumference of said hub.
- 9. The centrifugal separator according to claim 8, wherein said scraper assembly further comprises a plurality of feed passages for directing fluid to said plurality of scraper blades, said feed passages extending from said shaft spindle interface through said hub to each of said plurality of scraper blades.
- 10. The centrifugal separator according to claim 9, wherein each of said plurality of scraper blades is attached to said hub by a respective connecting member extending vertically from one of said points on the circumference of said hub.
- 11. The centrifugal separator according to claim 8, wherein said plurality of scraper blades comprise three scraper blades at equally spaced points on the circumference of said hub.
- 12. The centrifugal separator according to claim 1, wherein said shaft spindle and said scraper assembly comprise a fluid feed passage for channeling the fluid into said separator bowl.
- 13. The centrifugal separator according to claim 12, wherein each of said plurality of scraper blades comprises first and second openings in communication with said fluid feed passage, each of said first openings being disposed at a distal end of a respective one of said plurality of scraper blades adjacent to said interior surface of said separator bowl and each of said second openings being disposed at an intermediate position on a respective one of said scraper blades, said first and second openings for providing an outlet for the fluid feed passage proximate said interior surface of said separator bowl.
- 14. The centrifugal separator according to claim 1, further comprising a fluid feed cone positioned beneath said separator bowl for providing a fluid feed passage into said separator bowl from below said separator bowl.
- 15. The centrifugal separator according to claim 14, further comprising a feed cone positioner for raising said fluid feed cone to an upper position in mechanical communication with said separator bowl for feeding the fluid to said separator bowl and for lowering said fluid feed cone away from said separator bowl to enable the draining of liquid from said separator bowl.
- 16. A method for separating a fluid in a centrifugal separator, comprising the steps of:(a) rotating an elongated separator bowl and a scraper assembly and shaft spindle disposed therein about an axis at a high separating speed, said scraper assembly including a plurality of scraper blades extending substantially to an interior surface of said separator bowl, said scraper blades having a scraping width in the direction of said axis substantially less than the length of said separator bowl in the direction of said axis; (b) introducing a fluid to be separated into said separator bowl; (c) engaging said scraper assembly and said shaft spindle to prevent rotation thereof; (d) while said scraper assembly is engaged, rotating said separator bowl at a scraping speed substantially less than said separating speed; and (e) while said separator bowl is rotating at said scraping speed, axially moving said scraper assembly and said shaft spindle within said separator bowl to scrape solids that have accumulated along said interior surface of said separator bowl with said plurality of scraper blades.
- 17. The method according to claim 16, further comprising the step of introducing the fluid into said separator bowl through first and second openings on each of said plurality of scraper blades, each of said first openings being disposed at a distal end of a respective one of said scraper blades adjacent to said interior surface of said separator bowl and each of said second openings being disposed at an intermediate position on a respective one of said scraper blades.
- 18. A method for operating a centrifugal separator having a tubular separator bowl and an internal scraper assembly, said tubular separator bowl and said internal scraper assembly disposed for rotation about an axis of symmetry thereof, said method comprising the steps of:(a) draining liquid from said separator bowl, including the steps of (i) positioning a residual liquid container beneath a discharge port in said separator bowl to receive liquid drained from said separator bowl, and (ii) braking the rotation of said separator bowl and said internal scraper assembly; and (b) scraping solids accumulated on an interior surface of said separator bowl into a solids receiving container, including the steps of (i) moving said residual liquid container away from said discharge port whereby said solids receiving container is positioned to receive the scraped solids from said discharge port, (ii) engaging a scraper clutch so that said internal scraper assembly does not rotate with respect to said separator bowl, (iii) rotating said separator bowl while said scraper clutch is engaged, and (iv) while said separator bowl is rotating, moving said internal scraper assembly with respect to said separator bowl along said axis of symmetry.
- 19. The method according to claim 18, further comprising the steps of introducing a fluid to a shaft spindle of said internal scraper assembly and ejecting the fluid from first and second openings in each of a plurality of radial scraper blades of said internal scraper assembly, each of said first openings at the end of a respective one of said radial scraper blades adjacent an interior surface of said separator bowl and each of said second openings at an intermediate position on a respective one of said radial scraper blades.
- 20. The method according to claim 18 further comprising the step of rotating said separator bowl at a separating speed before said step of scraping to dry the solids accumulated in said separator bowl.
- 21. The method according to claim 18, further the step of feeding fluid into said rotatable separator bowl through said internal scraper assembly including the steps of(i) disengaging said scraper clutch from said internal scraper assembly to enable said internal scraper assembly to rotate with said separator bowl, (ii) rotating said separator bowl and said internal scraper assembly together at a separating speed, and (iii) flowing the fluid through feed passages in said internal scraper assembly and out exit ports disposed on said internal scraper assembly proximate said interior surface of said separator bowl.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119(e) to provisional patent application Ser. No. 60/223,409 filed Aug. 4, 2000, the disclosure of which is hereby incorporated by reference.
US Referenced Citations (34)
Foreign Referenced Citations (1)
Number |
Date |
Country |
3927707 |
Mar 1990 |
DE |
Non-Patent Literature Citations (3)
Entry |
Carr Powerfuge Brochure, Carr Separations, Inc., undated, p. 1-4. |
Alfa-Laval CHPX Centrifuge Brochure, Alfa Laval, Inc., undated, p. 1. |
Shanghai Centrifuge Institute, SCI Tube Bowl Centrifuge, Shanghai, China, undated, p. 1-2. |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/223409 |
Aug 2000 |
US |