Patent US4087893A successfully refreshed from Google Patents.
US4087893A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing a heat pipe
Assignee: Nippon Gakki Co Ltd
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Filing: 1975-11-05
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Granted: 1978-05-09
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Expires: 1995-11-05
Abstract
Abstract Through employment of a core-and-sheath construction having a number of axially elongated indentations along the border for the billet with the core of an easily soluble material, extrusion such as hydrostatic extrusion can advantageously be utilized for production of heat pipes with enhanced precision and operational efficiency in process. Indentations, which work as a wick in the heat pipe, may be provided by forming axially elongated grooves either in the inner peripheral surface of the sheath or in the outer peripheral surface of the core.
Inventors
- 👤 Takeo Sata
- 👤 Masayuki Takamura
- 👤 Norio Shinoda
- 👤 Masataka Hatae
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:42
CPC Classifications
F; F28; F28D; F28D15/00; F28D15/02; B; B21; B21C; B21C23/00; B21C23/007; B21C23/22; B21C33/00; B21C33/002; B21C33/004; B21C37/00; B21C37/06; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49353; Y10T29/4981
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
106 words
A process for producing a heat pipe, comprising the steps of: forming a billet comprising a water soluble salt core and an axially elongated non-water soluble sheath, said sheath including a plurality of axially extending capillary grooves formed along the inner periphery thereof, said salt core filling the interior of said sheath including said axially extending capillary grooves; subjecting said billet to compulsory plastic deformation by extrusion in such a manner that the dimensions of said sheath, including the dimensions of said capillary grooves, as measured in the radial direction are reduced; and thereafter removing said core through solution in water to obtain said heat pipe.
Claim 2
Dependent Claim
106 words
A process for producing a heat pipe, comprising the steps of: forming a billet comprising a water soluble salt core and an axially elongated non-water soluble sheath, said sheath including a plurality of axially extending capillary grooves formed along the inner periphery thereof, said salt core filling the interior of said sheath including said axially extending capillary grooves; subjecting said billet to compulsory plastic deformation by extrusion in such a manner that the dimensions of said sheath, including the dimensions of said capillary grooves, as measured in the radial direction are reduced; and thereafter removing said core through solution in water to obtain said heat pipe.
Claim 3
Dependent Claim
18 words
A process for producing a heat pipe as claimed in claim 1 wherein said extrusion is hydrostatic extrusion.
Claim 4
Dependent Claim
34 words
A process for producing a heat pipe as claimed in claim 1 wherein said water soluble salt is a simple salt chosen from a group composed of sodium sulfate, sodium carbonate and sodium chloride.
Claim 5
Dependent Claim
46 words
A process for producing a heat pipe as claimed in claim 1 wherein said water soluble salt is a compound salt including sodium carbonate as the base, 30 to 50 percent by weight of potassium chloride and less than 10 percent by weight of sodium chloride.
Claim 6
Dependent Claim
37 words
A process for producing a heat pipe as claimed in claim 1 wherein said water soluble salt is a compound salt including 30 percent by weight of sodium chloride and 70 percent by weight of sodium carbonate.
Claim 7
Dependent Claim
37 words
A process for producing a heat pipe as claimed in claim 1 wherein said water soluble salt is a compound salt including 50 percent by weight of potassium chloride and 50 percent by weight of sodium carbonate.
Claim 8
Dependent Claim
37 words
A process for producing a heat pipe as claimed in claim 1 wherein said water soluble salt is a compound salt including 80 percent by weight of potassium chloride and 20 percent by weight of calcium carbonate.
Claim 9
Dependent Claim
21 words
A process for producing a heat pipe as claimed in claim 1 wherein said sheath is made of a metallic material.
Claim 10
Dependent Claim
31 words
A process for producing a heat pipe as claimed in claim 8 wherein said metallic material is chosen from a group composed of aluminum, copper, brass, mild steel and their alloys.
Claim 11
Dependent Claim
29 words
A process for producing a heat pipe as claimed in claim 1 wherein said step of removing said core from said billet is carried out by blowing of steam.
Claim 12
Dependent Claim
24 words
A process for producing a heat pipe as claimed in claim 1 wherein a number of non-water soluble beads are mixed into said core.
Claim 13
Dependent Claim
64 words
A proces for producing a heat pipe as claimed in claim 1 wherein said step of forming a billet includes the steps of: forming a sheath pipe having a number of axially elongated grooves in the inner peripheral surface thereof; and inserting said water soluble core into the cavity of said sheath pipe such that said core completely fills said cavity including said grooves.
Claim 14
Dependent Claim
27 words
A process for producing a heat pipe as claimed in claim 12 wherein said sheath is formed by machine cutting an inner cavity of a material pipe.
Claim 15
Dependent Claim
19 words
A process for producing a heat pipe as claimed in claim 12 wherein said sheath is formed by casting.
Claim 16
Dependent Claim
75 words
A process for producing a heat pipe as claimed in claim 1 wherein said step of forming said billet includes the steps of: forming a material core by compaction; forming a number of axially elongated grooves in the periphery of said material core; setting said material core in a mold; and casting a metallic material between said core in said mold whereby said grooves are formed along said border between said core and said sheath.
Claim 17
Dependent Claim
20 words
A process for producing a heat pipe as claimed in claim 15 wherein said grooves are formed by machine cutting.
Claim 18
Dependent Claim
19 words
A process for producing a heat pipe as claimed in claim 15 wherein said grooves are formed by casting.
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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) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |