Patent US2740289A successfully refreshed from Google Patents.
US4658601A
Expired / Lapsed
US
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Cryogenic cell
Assignee: BP PLC
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Filing: 1985-02-27
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Granted: 1987-04-21
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Expires: 2005-02-27
Abstract
Abstract A cryogenic cell comprises a sealed external annular chamber, adapted to be maintained under vacuum which chamber surrounds a heat shield. A section of the shield is exposed and is adapted to make contact with a closed cycle cooler. The shield encloses a sealed inner chamber adapted for the storage of a solid/liquid refrigerant. The shield has a relatively thin base and sidewall and the section which is exposed is a relatively thick upper collar which has a well leading to the top of the inner chamber immediately above and in contact with the top of the inner chamber. The inner chamber is connected at its lower end to a section containing an absorbent and the latter section is connected at its lower end to a further chamber suitable for the reception of a gamma radiation detector. The cryogenic cell is suitable for keeping the semi-conductor detector of a neutron borehole logging tool at the required low temperature.
Inventors
- 👤 Steven P. Burchell
- 👤 Nicholas W. Kerley
- 👤 David W. Mellor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:38
CPC Classifications
F; F17; F17C; F17C3/00; F17C3/02; F17C3/08; F17C3/085; E; E21; E21B; E21B36/00; E21B36/001; F25; F25D; F25D3/00; G; G01; G01V; G01V5/00; G01V5/04; F17C2201/00; F17C2201/03; F17C2201/032; F17C2203/00; F17C2203/01; F17C2203/014; F17C2203/018; F17C2203/03; F17C2203/0375; F17C2203/0387; F17C2203/0391; F17C2203/06; F17C2203/0602; F17C2203/0612; F17C2203/0626; F17C2203/0631; F17C2203/0634; F17C2203/0636; F17C2203/0639; F17C2203/0643; F17C2260/00; F17C2260/03; F17C2260/031; F17C2260/033; F17C2260/04; F17C2260/042; F17C2260/05; F17C2260/053; F17C2270/00; F17C2270/05; F17C2270/0518; F17C2270/0545; F25D3/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
171 words
A neutron logging tool comprising a probe containing in sequence from the bottom end a source of neutrons, a shield against radioactivity, a semiconductor detector for gamma radiation and a cryogenic cell comprising an external annular chamber, adapted to be maintained under vacuum and partially enclosing a heat shield fabricated from a metal of high thermal conductivity and high specific heat capacity, surrounding and spaced apart from an enclosed inner chamber adapted for the storage of a solid/liquid refrigerant, the space between the heat shield and the chamber forming an annular chamber adapted to be maintained under vacuum, the heat shield having a relatively thin base and sidewall and a relatively thick exposed upper collar having a well therein leading to the top of the chamber, the collar, well and top of the chamber being adapted to receive a "cold finger" to lower the temperature of the shield and chamber, the chamber being connected at its lower end to a further chamber suitable for the reception of a gamma radiation detector.
Claim 2
Dependent Claim
171 words
A neutron logging tool comprising a probe containing in sequence from the bottom end a source of neutrons, a shield against radioactivity, a semiconductor detector for gamma radiation and a cryogenic cell comprising an external annular chamber, adapted to be maintained under vacuum and partially enclosing a heat shield fabricated from a metal of high thermal conductivity and high specific heat capacity, surrounding and spaced apart from an enclosed inner chamber adapted for the storage of a solid/liquid refrigerant, the space between the heat shield and the chamber forming an annular chamber adapted to be maintained under vacuum, the heat shield having a relatively thin base and sidewall and a relatively thick exposed upper collar having a well therein leading to the top of the chamber, the collar, well and top of the chamber being adapted to receive a "cold finger" to lower the temperature of the shield and chamber, the chamber being connected at its lower end to a further chamber suitable for the reception of a gamma radiation detector.
Claim 3
Dependent Claim
142 words
A cryogenic cell comprising an external annular chamber, adapted to be maintained under vacuum and partially enclosing a heat shield fabricated from a metal of high thermal conductivity and high specific heat capacity, surrounding and spaced apart from an enclosed inner chamber adapted for the storage of a solid/liquid refrigerant, the space between the heat shield and the chamber forming an annular chamber adapted to be maintained under vacuum, the heat shield having a relatively thin base and sidewall and a relatively thick exposed upper collar having a well therein leading to the top of the chamber, the collar, well and top of the chamber being adapted to receive a "cold finger" to lower the temperature of the shield and chamber, the chamber being connected at its lower end to a further chamber suitable for the reception of a gamma radiation detector.
Claim 4
Dependent Claim
142 words
A cryogenic cell comprising an external annular chamber, adapted to be maintained under vacuum and partially enclosing a heat shield fabricated from a metal of high thermal conductivity and high specific heat capacity, surrounding and spaced apart from an enclosed inner chamber adapted for the storage of a solid/liquid refrigerant, the space between the heat shield and the chamber forming an annular chamber adapted to be maintained under vacuum, the heat shield having a relatively thin base and sidewall and a relatively thick exposed upper collar having a well therein leading to the top of the chamber, the collar, well and top of the chamber being adapted to receive a "cold finger" to lower the temperature of the shield and chamber, the chamber being connected at its lower end to a further chamber suitable for the reception of a gamma radiation detector.
Claim 5
Dependent Claim
17 words
A cryogenic cell according to claim 2 wherein the walls of the heat shield are highly polished.
Claim 6
Dependent Claim
23 words
A cryogenic cell according to claim 2 wherein the chamber is connected to the chamber by way of a section containing an absorbent.
Claim 7
Dependent Claim
20 words
A cryogenic cell according to claim 2 wherein the outer wall of the external chamber is fabricated from stainless steel.
Claim 8
Dependent Claim
30 words
A cryogenic cell according to claim 2 wherein the wall of the chamber are highly polished and fabricated from a metal of high thermal conductivity, and high specific heat capacity.
Claim 9
Dependent Claim
25 words
A cryogenic cell according to either of claims 3 or 6 wherein the metal of high thermal conductivity and high specific heat capacity is copper.
Claim 10
Dependent Claim
15 words
A cryogenic cell according to claim 7 wherein the copper is oxygen-free high conductivity copper.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |