US3699343A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Condensation heated black body radiation source
Assignee: Lockheed Martin Corp
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Filing: 1969-08-19
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Granted: 1972-10-17
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Expires: 1989-08-19
Abstract
Abstract An isothermal black body radiation source comprises a double reentrant radiating cavity disposed within a heat pipe. Wicking material surrounds the outer surface of the radiating cavity and the heat pipe sidewalls. Heat is supplied to the heat pipe by an electrical winding or other suitable heating means, thereby vaporizing a working fluid. The vapors are condensed on the cavity outer walls thereby releasing their latent heat of vaporization and heating the cavity wall to a uniform temperature. The cavity then radiates energy through an exit aperture. In an alternative embodiment the radiating cavity is disposed within a reflux tube.
Inventors
- 👤 Bernard Stein
- 👤 Sheridan Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:55
CPC Classifications
F; F28; F28D; F28D15/00; F28D15/02; F28D15/0233; G; G01; G01J; G01J5/00; G01J5/52; G01J5/53; H; H05; H05B; H05B3/00; H05B3/0014
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
99 words
An improved black body radiation source comprising an evaporative heat transfer chamber having an evaporator portion and a condenser portion, a working fluid disposed within said chamber, means for heating the evaporator portion of said chamber to thereby vaporize a portion of said working fluid, a radiation cavity having an exit aperture, disposed in the condenser portion of said chamber, and having an outer surface whereon vapors condense thereby heating said cavity to a substantially uniform preselected temperature such that radiation is emitted through said aperture, and means for returning the condensate to said evaporator portion of said chamber.
Claim 2
Dependent Claim
99 words
An improved black body radiation source comprising an evaporative heat transfer chamber having an evaporator portion and a condenser portion, a working fluid disposed within said chamber, means for heating the evaporator portion of said chamber to thereby vaporize a portion of said working fluid, a radiation cavity having an exit aperture, disposed in the condenser portion of said chamber, and having an outer surface whereon vapors condense thereby heating said cavity to a substantially uniform preselected temperature such that radiation is emitted through said aperture, and means for returning the condensate to said evaporator portion of said chamber.
Claim 3
Dependent Claim
50 words
Apparatus as recited in claim 1 wherein said evaporative heat transfer chamber is a heat pipe having a capillary structure disposed about the outer surface of said cavity and the sidewalls of said chamber whereby said condensate is returned from said condenser portion to said evaporator portion by capillary pressure.
Claim 4
Dependent Claim
27 words
Apparatus as recited in claim 2 wherein said capillary structure is a wick formed of a material which is wetted by but nonreactive with said working fluid.
Claim 5
Dependent Claim
20 words
Apparatus as recited in claim 3 wherein said wick is formed of a plurality of layers of stainless steel screen.
Claim 6
Dependent Claim
44 words
Apparatus as recited in claim 1 wherein said evaporative heat transfer chamber is a reflux tube having a condenser portion which is elevated with respect to said evaporator portion whereby said condensate is returned from said condenser portion to said evaporator portion by gravity.
Claim 7
Dependent Claim
36 words
Apparatus as recited in claim 5 further including means disposed within said reflux tube between said evaporator and said condenser for preventing direct contact of said working fluid in the liquid phase with said radiation cavity.
Claim 8
Dependent Claim
14 words
Apparatus as recited in claim 1 wherein said working fluid is a liquid metal.
Claim 9
Dependent Claim
30 words
Apparatus as recited in claim 7 wherein said liquid metal is selected from the group of liquid metals consisting of: lithium, cesium, sodium, bismuth, lead, lead-bismuth potassium, tin, and sodium-potassium.
Claim 10
Dependent Claim
12 words
Apparatus as recited in claim 1 wherein said working fluid is silver.
Claim 11
Dependent Claim
23 words
Apparatus as recited in claim 1 further including a layer of high emissivity material disposed on the inner surface of said radiation cavity.
Claim 12
Dependent Claim
22 words
Apparatus as recited in claim 1 further including a low emissivity aperture plate disposed about said exit aperture of said radiation cavity.
Claim 13
Dependent Claim
20 words
Apparatus as recited in claim 1 further including temperature sensing means disposed proximate the outer surface of said radiation cavity.
Claim 14
Dependent Claim
24 words
Apparatus as recited in claim 12 wherein said temperature sensing means is coupLed to and operative to control the output of said heating means.
Claim 15
Dependent Claim
41 words
Apparatus as recited in claim 1 further including means for insulating said condenser portion of said chamber except for said radiation cavity exit aperture to thereby substantially preclude the emission of radiation from any portion of the apparatus except said aperture.
Claim 16
Dependent Claim
16 words
Apparatus as recited in claim 1 wherein said radiation cavity is a double reentrant cone cavity.
Claim 17
Dependent Claim
16 words
Apparatus as recited in claim 15 wherein said double reentrant cone has a divergence of 28*.
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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) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |