1. A method for cooling an article using a cryocooler, comprising the steps of:
setting a stationary point on a cold end of a cryocooler, and
mounting an article onto said stationary point to be cooled.
2. The cooling method as defined in claim 1, wherein said cold end is formed in circular shape, and said stationary point is set on an area substantially near and along a diameter of said cold end.
3. The cooling method as defined in claim 2, wherein said stationary point is set on an almost center of said cold end.
4. The cooling method as defined in claim 1, wherein two pairs of cooling cylinders are connected with said cold end so that a diagonal line connecting one pair of cooling cylinders is orthogonal to another diagonal line connecting the other pair of cooling cylinders, and a high pressure gas is supplied to the one pair of cooling cylinders and a low pressure gas is supplied to the other pair of cooling cylinders so that said stationary point is set on said cold end.
5. The cooling method as defined in claim 4, further comprising the steps of shifting a supply cycle of said high pressure gas from another supply cycle of said low pressure gas by a phase shift of 180 degrees and making said cold end of rigid material, wherein said cold end is not vibrated and said stationary point is set over said cold end.
6. A cryocooler comprising:
two pairs of cooling cylinders, and
a cold end with which said two pairs of cooling cylinders are connected so that a diagonal line connecting one pair of cooling cylinders is orthogonal to another diagonal line connecting the other pair of cooling cylinders,
wherein a high pressure gas is supplied to the one pair of cooling cylinders and a low pressure gas is supplied to the other pair of cooling cylinders so that a stationary point is set on said cold end.
7. The cryocooler as defined in claim 6, wherein said cold end is formed in circular shape and said stationary point is set on an area substantially near and along a diameter of said cold end.
8. The cryocooler as defined in claim 7, wherein said stationary point is set on an almost center of said cold end.
9. The cryocooler as defined in claim 8, wherein said cold end is made of rigid material, and a supply cycle of said high pressure gas is shifted from another supply cycle of said low pressure gas by a phase shift of 180 degrees so that said stationary point is set over said cold end.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus for visually detecting wear to an insert bowl, bushing, or spider, comprising:
a bowl having a central bore defined by an inner surface, said inner surface including an upper tapered section for engaging slips supporting a work string and a lower section;
a wear indicator means formed in the inner surface of said bowl, said wear indicator means providing a visual indicator of wear to the inner surface of said bowl.
2. The apparatus according to claim 1, wherein said wear indicator means comprises a groove.
3. The apparatus according to claim 2, wherein said groove is a substantially horizontal groove.
4. The apparatus according to claim 3, wherein said substantially horizontal groove extends around a circumference of the inner surface of said bowl.
5. An apparatus for visually detecting wear to an insert bowl, bushing, or spider, comprising:
a bowl having a central bore defined by an inner surface, said inner surface including an upper tapered section for engaging slips supporting a work string and a lower section;
a wear indicator means formed in the lower section of the inner surface of said bowl, said wear indicator means providing a visual indicator of wear to the inner surface of said bowl.
6. The apparatus according to claim 5, wherein said wear indicator means comprises a groove.
7. The apparatus according to claim 6, wherein said groove is a substantially horizontal groove.
8. The apparatus according to claim 7, wherein said substantially horizontal groove extends around a circumference of the inner surface of said bowl.
9. An apparatus for visually detecting wear to an insert bowl, bushing, or spider, comprising:
a bowl having a central bore defined by an inner surface, said inner surface including an upper tapered section for engaging slips supporting a work string and a lower section;
a groove formed in the inner surface of said bowl, said groove having an initial non-wear depth of at least \xbc inch, said groove providing a visual indicator of wear to the inner surface of said bowl.
10. The apparatus according to claim 9, wherein said groove is formed in the lower section of the inner surface of said bowl.
11. The apparatus according to claim 10, wherein said groove is a substantially horizontal groove.
12. The apparatus according to claim 11, wherein said substantially horizontal groove extends around a circumference of the inner surface of said bowl.
13. An apparatus for visually detecting wear to an insert bowl, bushing, or spider, comprising:
a bowl having a central bore defined by an inner surface, said inner surface including an upper tapered section for engaging slips supporting a work string and a lower section;
a first substantially horizontal groove formed in the inner surface of said bowl;
a second substantially horizontal groove formed in the inner surface of said bowl;
said first and second substantially horizontal grooves providing a visual indicator of wear to the inner surface of said bowl.
14. The apparatus according to claim 13, wherein said first substantially horizontal groove has an initial non-wear depth less than an initial non-wear depth of said second substantially horizontal groove.
15. The apparatus according to claim 13, wherein said first substantially horizontal groove is formed in the upper tapered section of the inner surface of said bowl and said second substantially horizontal groove is formed in the lower section of the inner surface of said bowl.
16. The apparatus according to claim 13, wherein said first and second substantially horizontal grooves are each formed in the lower section of the inner surface of said bowl.
17. A method of visually detecting wear to an insert bowl, bushing, or spider, comprising the steps of:
a) providing a bowl having a central bore defined by an inner surface, said inner surface including an upper tapered section for engaging slips supporting a work string, a lower section, and a wear indicator means, said wear indicator means being formed in the inner surface of said bowl and providing a visual indicator of wear to the inner surface of said bowl; and
b) visually inspecting said wear indicator means for existence of wear to the inner surface of said bowl.
18. The method according to claim 17, wherein an inability to visually detect at least a portion of said wear indicator means signifies wear to the inner surface of said bowl that indicates that replacement of said bowl is necessary.
19. The method according to claim 17, wherein said wear indicator means is formed in the lower section of the inner surface of said bowl.
20. The method according to claim 17, wherein said wear indicator means comprises a groove.
21. The method according to claim 20, wherein said groove is a substantially horizontal groove.
22. The method according to claim 21, wherein said substantially horizontal groove extends around a circumference of the inner surface of said bowl.
23. The method according to claim 20, wherein said groove is machined in the inner surface of said bowl.
24. The method according to claim 23, wherein said groove is machined to an initial non-wear depth of at least \xbc inch.
25. A method of visually detecting wear to an insert bowl, bushing, or spider, comprising the steps of:
a) providing a bowl having a central bore defined by an inner surface, said inner surface including an upper tapered section for engaging slips supporting a work string, a lower section, a first substantially horizontal groove, and a second substantially horizontal groove, said first and second horizontal grooves each being formed in the inner surface of said bowl and providing a visual indicator of wear to the inner surface of said bowl; and
b) visually inspecting said first and second substantially horizontal grooves for existence of wear to the inner surface of said bowl.
26. The method according to claim 25, wherein said first substantially horizontal groove has an initial non-wear depth less than an initial non-wear depth of said second substantially horizontal groove.
27. The method according to claim 26, wherein an inability to visually detect at least a portion of said first substantially horizontal groove signifies wear to the inner surface of said bowl that does not indicate that replacement of said bowl is necessary and an inability to detect at least a portion of said second substantially horizontal groove signifies wear to the inner surface of said bowl that indicates that replacement of said bowl is necessary.
28. The method according to claim 25, wherein said first substantially horizontal groove is formed in the upper tapered section of the inner surface of said bowl and said second substantially horizontal groove is formed in the lower section of the inner surface of said bowl.
29. The method according to claim 25, wherein said first and second substantially horizontal grooves are each formed in the lower section of the inner surface of said bowl.