Process irradiator

• US 6,274,100 B1
• Filed: 11/04/1999
• Issued: 08/14/2001
• Est. Priority Date: 11/05/1998
• Status: Expired due to Term

• Current Assignee: J.L. Shepherd & Associates
• Original Assignee: JL Shepherd & Associated
• Inventors: Shepherd, Thomas J., Shepherd, Joseph L.
• Primary Examiner(s): Mayekar, Kishor
• Application Number:
  US09/434,215
• Time in Patent Office: 649 Days
• Field of Search: 422/186.3, 422/22, 250/492.1, 250/496.1, 250/455.11
• US Class Current: 422/186.3
• CPC Class Codes: A61L 2/08 Radiation

Abstract

A process irradiator includes a heavily shielded, generally cylindrical, housing with a heavily shielded top. A radiation source includes source elements in several tubes extending from the top into a shielded storage cask below the center of the housing floor. A circular track concentrically positioned relative to the track guides a motor-driven carousel carrying a number of turntables which carry material to be irradiated, the turntables being rotatable on their axes. A heavy shielded door provides access to the turntables which are successively rotated on the carousel to a position adjacent the door opening. A lifting structure on the top includes two or more lifting devices which permit selective lifting of the source elements from the storage cask into the housing. Interlock controls prevent the door from opening and the carousel from rotating unless all source elements are stored in the storage cask.

Claims

1. A process irradiator comprising a generally cylindrical shielded housing having a floor, a wall, a top, an opening in said wall and a door for closing said opening;

a shielded storage cask;

a radiation source in said housing movable between said storage cask and an irradiating position in said housing, said radiation source comprising a plurality of source elements and a plurality of tubes containing and guiding said source elements;

a plurality of turntables and means for rotating said turntables substantially equidistant from said source; and

means for successively moving said turntables to a position adjacent to said door.

2. A process irradiator as claimed in claim 1 wherein a perforated cylindrical member is positioned concentrically around said tubes.

3. A process irradiator as claimed in claim 1 further comprising shielding material in said tubes above said source elements such that when said sources are in said storage cask a minimum of radiation is present in said housing.

4. A process irradiator as claimed in claim 1 further comprising interlock controls such that said door cannot be opened unless said sources are in their fully shielded position and said sources cannot be moved to their unshielded position in said housing unless said door is closed and locked and which prevent said door from closing unless all said turntables are moved to positions away from said door.

5. A process irradiator as claimed in claim 1 wherein said means for successively moving said turntables comprises a track and rotatable concentrically around said radiation source on said track and said turntables are positioned on said carousel.

6. A process irradiator as claimed in claim 5 wherein said means for rotating said turntables comprises a motor positioned on said top.

7. A process irradiator as claimed in claim 6 further comprising a separate drive motor for driving said carousel.

8. A process irradiator as claimed in claim 1 wherein said wall and top are of steel plate and shielding for said wall and said top are of earth.

9. A process irradiator as claimed in claim 1 wherein said source elements and tubes are arranged in groups and a separate lifting fixture is attached to each group such that said groups of source elements and tubes may be selectively raised into said housing from said storage cask.

10. A process irradiator comprising a generally cylindrical shielded housing, an opening in said housing and a door movable to open and close said opening;

a shielded storage cask;

a source of radiation and a structure for moving said source between a shielded position in said storage cask and an irradiating position in the inside of said housing, said source of radiation being generally centered in said housing;

a generally circular track positioned concentrically outwardly of said source;

a carousel movable to a plurality of positions along said track around said source of radiation; and

a plurality of turntables carried on said carousel and rotatable on their axes.

11. A process irradiator as claimed in claim 10 wherein said radiation source comprises a plurality of source elements and a plurality of tubes containing and guiding said source elements.

12. A process irradiator as claimed in claim 11 further comprising shielding material in said tubes above said source elements such that when said sources are in said storage cask a minimum of radiation is present in said housing.

13. A process irradiator comprising a shielded housing having a floor, a wall, a top and an opening;

shielding material, a shielded storage cask below said housing and a radiation source in said housing movable between a shielded position in said storage cask and an unshielded position within said housing, said radiation source comprising a plurality of source elements and a plurality of tubes containing and guiding said source elements;

a perforated cylindrical member positioned concentrically around said tubes;

a lifting structure for raising said source elements from said storage cask to the interior of said housing and returning said source elements to said storage cask;

a generally circular track in said housing positioned concentrically outwardly of said source;

a plurality of turntables movable to a plurality of positions along said track, said turntables being rotatable in position;

a shielded door closing said opening and providing access when open to one of said turntables when said turntable is moved to a position adjacent said door; and

containers carried on said turntables for containing material to be irradiated.

14. A process irradiator as claimed in claim 13 wherein said lifting structure is positioned above said top and comprises electro-pneumatically-powered cable cylinders.

15. A process irradiator as claimed in claim 13 wherein said source elements and tubes are arranged in groups and a separate lifting fixture is attached to each group such that said groups of source elements and tubes may be selectively raised into said housing from said storage cask.

16. A process irradiator as claimed in claim 15 wherein each group of sources is connected to a block and one of said blocks includes ports permitting tubes of another of said groups to extend through said ports.

17. A process irradiator as claimed in claim 15 further comprising shielding material in said tubes above said source elements such that when said sources are in said storage cask a minimum of radiation is present in said housing.

18. A process irradiator as claimed in claim 13 further comprising interlock controls such that said door cannot be closed until said carousel is rotated to carry said turntables away from a door open position.

19. A process irradiator comprising a generally cylindrical shielded housing having an opening and a door for closing said opening;

a shielded storage cask;

a source of radiation generally centered in said housing and movable between said storage cask and an irradiating position in said housing;

a circular track in said housing positioned concentrically outwardly of said source;

a plurality of turntables and means for rotating said turntables on their axes;

a carousel movable to a plurality of positions along said track carrying said turntables concentrically with respect to said irradiation source; and

interlock controls which prevent said door from closing unless said carousel is rotated away from a door open position.

20. A process irradiator as claimed in claim 19 wherein said radiation source comprises a plurality of source elements and a plurality of tubes containing and guiding said source elements.