US4159359A
Expired / Lapsed
US
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Insulating material with low thermal conductivity, formed of a compacted granular structure
Assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Filing: 1977-08-05
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Granted: 1979-06-26
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Expires: 1997-08-05
Abstract
Abstract Insulating material, of compacted structure and of low thermal conductivity, is formed of silica-based primary particles; it is obtained by heat treatment of a compound of silane, of which the mean diameter is at most equal to 100 A; the apparent density ρa expressed in g/cc is between 6.10 -3 and 2.3.10 -3 d, d being the mean diameter of the primary particles expressed in A; in addition, this apparent density is at most equal to two thirds of the density of the solid material. This material is applicable as a thermal insulator in the field involving low temperatures and high temperatures and in the building sector.
Inventors
- 👤 Pierre Pelloux-Gervais
- 👤 Daniel Goumy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:18
CPC Classifications
C; C04; C04B; C04B30/00; F; F16; F16L; F16L59/00; F16L59/02; F17; F17C; F17C13/00; F17C13/001; F27; F27D; F27D1/00; F27D1/0003; F27D1/0006; F17C2203/00; F17C2203/03; F17C2203/06; F17C2203/0634; F17C2203/0636; F17C2203/0658; F17C2203/066; F17C2221/00; F17C2221/01; F17C2221/016; F17C2223/00; F17C2223/01; F17C2223/0146; F17C2223/0153; F17C2223/0161; Y; Y10; Y10T; Y10T428/00; Y10T428/23; Y10T428/239; Y10T428/29; Y10T428/2982; Y10T428/31504; Y10T428/31652; Y10T428/31663
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
121 words
Insulating material having low thermal conductivity, formed of a compacted granular structure of silica-based primary particles, wherein the silica powder is obtained by heat treatment or pyrogenation of a silane compound; the mean diameter of the primary particles being at most equal to 100 A; said silica-based, ultra-fine primary particles having been compacted mechanically to provide an apparent density of the compacted structure, expressed in g/cc, being 6×10 -3 d and 2.3×10 -3 d wherein d is the mean diameter of the primary particles expressed in A; said apparent density being at most equal to two thirds of the density of the solid material; and said granular compacted structure containing at least 0.8×10 16 ×(500/d) 2 primary particles per cubic centimeter.
Claim 2
Dependent Claim
121 words
Insulating material having low thermal conductivity, formed of a compacted granular structure of silica-based primary particles, wherein the silica powder is obtained by heat treatment or pyrogenation of a silane compound; the mean diameter of the primary particles being at most equal to 100 A; said silica-based, ultra-fine primary particles having been compacted mechanically to provide an apparent density of the compacted structure, expressed in g/cc, being 6×10 -3 d and 2.3×10 -3 d wherein d is the mean diameter of the primary particles expressed in A; said apparent density being at most equal to two thirds of the density of the solid material; and said granular compacted structure containing at least 0.8×10 16 ×(500/d) 2 primary particles per cubic centimeter.
Claim 3
Dependent Claim
50 words
Insulating material having low thermal conductivity in accordance with claim 1, wherein the mean diameter of the primary particles of the silica powder is between 25 and 100 A and the number of primary particles per cubic centimeter is between 0.8×10 16 ×(500/d) 2 and 2.1×10 16 ×(500/d) 2 .
Claim 4
Dependent Claim
37 words
Insulating material having low thermal conductivity in accordance with claim 1, wherein the apparent density of said compacted structure is about 4×10 -3 d, and the number of primary particles is about 1.4×10 16 ×(500/d) 2 .
Claim 5
Dependent Claim
18 words
Insulating material in accordance with claim 1, wherein the silica powder is obtained by heat treatment of tetrachlorosilane.
Claim 6
Dependent Claim
13 words
Insulating material in accordance with claim 1, wherein the particles comprise alkylated silica.
Claim 7
Dependent Claim
13 words
Insulating material in accordance with claim 5, wherein the particles comprise methylated silica.
Claim 8
Dependent Claim
14 words
Insulating material in accordance with claim 1 in the form of bricks or panels.
Claim 9
Dependent Claim
37 words
Insulating material in accordance with claim 7, wherein said bricks or panels are covered with a skin selected from the group consisting of polyethylene, polyethylene terephthalate, polyvinyl chloride, epoxy adhesive, metallic foil or a metalloplastic material layer.
Claim 10
Dependent Claim
24 words
Insulating material in accordance with claim 8, wherein the permeability of said tight skin covering is less than <10 -7 t1/s cm 2 ).
Claim 11
Dependent Claim
21 words
Insulating material in accordance with claim 8, wherein the gas located between the ultra-fine silica-based particles comprises a low conductivity gas.
Claim 12
Dependent Claim
23 words
Insulating material in accordance with claim 10, wherein said low conductivity gas is selected from the group consisting of krypton, xenon and Freon.
Claim 13
Dependent Claim
38 words
In a refrigerator for containing or transporting products therewithin at a low temperature, and comprising at least one wall having a thermal insulating layer, the improvement wherein said thermal insulating layer comprises the insulating material of claim 1.
Claim 14
Dependent Claim
24 words
In an oven or furnace having at least one insulating wall, the improvement wherein said insulating wall comprises the insulating material of claim 1.
Claim 15
Dependent Claim
19 words
In a building comprising an insulating wall, the improvement wherein said insulating wall comprises the material of claim 1.
Claim 16
Dependent Claim
35 words
Insulating material in accordance with claim 1 having a mean thermal conductivity on the order of 50 μW cm -1 K -1 for a high internal gas pressure on the order of P≦100 mm Hg.
Claim 17
Dependent Claim
22 words
Insulating material in accordance with claim 1 having a thermal conductivity less than 150 μW cm -1 K -1 at atmospheric pressure.
References Cited (Backward Citations)
US3151365A
Cited
US3962014A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-06-25 | 1982-12-25 | 1983-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-25 | 1986-12-25 | 1987-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-25 | 1990-12-25 | 1991-06-26 | $7700.00 | Window Closed / Lapsed |