US4606194A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryocooler having low magnetic signature
Assignee: Azenta Inc
•
Filing: 1983-11-18
•
Granted: 1986-08-19
•
Expires: 2003-11-18
Abstract
Abstract A cryocooler 8 is described which has a low magnetic signature in which a ceramic displacer 10 reciprocates within a helium impenetrable cold finger cylinder 12. A cyrogenic refrigerator formed by the displacer and the cold finger cylinder cools a cold space 22 to cryogenic temperature. The cold space 22 is magnetically shielded from a drive motor 18 which both drives the displacer 10 and compressor pistons 14, 15, 16. The motor is magnetically shielded by means of magnetic shields 70, 72, 74, 90, 76, 78, 80, 82.
Inventors
- 👤 F. William Pirtle
- 👤 Harry G. Nicoll
- 👤 Peter K. Bertsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:11
CPC Classifications
F; F25; F25B; F25B9/00; F25B9/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
149 words
A cryogenic refrigerator comprising a gap regenerator which comprises: a support member adapted to serve as a radiation shield; a drive member extending through the support member; a ceramic displacer driven by the drive member; a vacuum tight rigid cermaic cold finger which is substantially helium impenetrable supported by the support member and surrounding the displacer and forming a gap regenerator therewith; a dome supported by the support member on the side thereof opposite to the cold finger, the dome forming a vacuum vessel and serving as a high magnetic permeability radiation shield; counterbalance rotary-to-linear electromagnetic drive means within the dome for driving the displacer driver member; a plurality of dome-like high magnetic permeability radiation shields supported by the support member and surrounding the electromagnetic drive means; and a plurality of radiation shields surrounding the displacer driver member and positioned between the support member and the electromagnetic drive means.
Claim 2
Dependent Claim
149 words
A cryogenic refrigerator comprising a gap regenerator which comprises: a support member adapted to serve as a radiation shield; a drive member extending through the support member; a ceramic displacer driven by the drive member; a vacuum tight rigid cermaic cold finger which is substantially helium impenetrable supported by the support member and surrounding the displacer and forming a gap regenerator therewith; a dome supported by the support member on the side thereof opposite to the cold finger, the dome forming a vacuum vessel and serving as a high magnetic permeability radiation shield; counterbalance rotary-to-linear electromagnetic drive means within the dome for driving the displacer driver member; a plurality of dome-like high magnetic permeability radiation shields supported by the support member and surrounding the electromagnetic drive means; and a plurality of radiation shields surrounding the displacer driver member and positioned between the support member and the electromagnetic drive means.
Claim 3
Dependent Claim
122 words
A cryocooler for cooling electronic devices to cryogenic temperatures having a low magnetic signature which comprises: electromagnetic drive means; a compressor driven by the electromagnetic drive means; a ceramic displacer driven by the electromagnetic drive means; a ceramic cold finger cyclinder wherein the outer surface of said cold finger cylinder comprises a non-porous metallic coating and wherein the inner surface of said cold finger cyclinder reciprocally receives said displacer to form a gap regenerator for cooling said cold finger; a plurality of dome-like high magnetic permeability radiation shields surrounding the electromagnetic drive means and the compressor but open toward the displacer; and a plurality of high magnetic permeability radiation shields surrounding a drive member between the electromagnetic drive means and the displacer.
Claim 4
Dependent Claim
122 words
A cryocooler for cooling electronic devices to cryogenic temperatures having a low magnetic signature which comprises: electromagnetic drive means; a compressor driven by the electromagnetic drive means; a ceramic displacer driven by the electromagnetic drive means; a ceramic cold finger cyclinder wherein the outer surface of said cold finger cylinder comprises a non-porous metallic coating and wherein the inner surface of said cold finger cyclinder reciprocally receives said displacer to form a gap regenerator for cooling said cold finger; a plurality of dome-like high magnetic permeability radiation shields surrounding the electromagnetic drive means and the compressor but open toward the displacer; and a plurality of high magnetic permeability radiation shields surrounding a drive member between the electromagnetic drive means and the displacer.
Claim 5
Dependent Claim
42 words
The crycooler for cooling electronic devices described in claim 2 further comprising: at least one thermal radiation shield joined to the ceramic cold finger cylinder and surrounding a cold space for the placement of said electronic devices adjacent to said cold finger.
Claim 6
Dependent Claim
18 words
The cryocooler of claim 3 further comprising a thermal damper positioned between said cold finger and cold space.
Claim 7
Dependent Claim
95 words
A cryogenic refrigerator comprising: a cold space for mounting an electronic device; a machinable glass ceramic displacer; a machinable glass ceramic cold finger surrounding said displacer wherein said cold finger is metal coated to form a helium sealed environment for said displacer of low magnetic signature; drive means for moving said displacer within said cylinder; a plurality of dome-like high permeability magnetic radiation shields surrounding the electromagnetic drive means but open toward the displacer; and a plurality of high permeability magnetic radiation shields surrounding a drive member between the electromagnetic drive means and the displacer.
Claim 8
Dependent Claim
95 words
A cryogenic refrigerator comprising: a cold space for mounting an electronic device; a machinable glass ceramic displacer; a machinable glass ceramic cold finger surrounding said displacer wherein said cold finger is metal coated to form a helium sealed environment for said displacer of low magnetic signature; drive means for moving said displacer within said cylinder; a plurality of dome-like high permeability magnetic radiation shields surrounding the electromagnetic drive means but open toward the displacer; and a plurality of high permeability magnetic radiation shields surrounding a drive member between the electromagnetic drive means and the displacer.
Claim 9
Dependent Claim
17 words
The cryogenic refrigerator of claim 5 wherein said drive means comprises a brushless direct current electric motor.
Claim 10
Dependent Claim
14 words
The cryogenic refrigerator of claim 6 wherein said motor operates in a sealed housing.
Claim 11
Dependent Claim
26 words
The cryogenic refrigerator of claim 5 wherein said drive means comprises an electric motor having a rotating shaft and said shaft is counterbalanced to reduce vibration.
Claim 12
Dependent Claim
17 words
The cryogenic refrigerator of claim 5 further comprising a superconducting electronic device adjacent to said cold finger.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |