The conformal thermal insulating blanket may have generally rigid batting material covered by an outer insulating layer formed of a high temperature resistant woven ceramic material and an inner insulating layer formed of a woven ceramic fiber material. The batting and insulating layers may be fastened together by sewing or stitching using an outer mold layer thread fabricated of a high temperature resistant material and an inner mold layer thread of a ceramic fiber material. The batting may be formed to a composite structure that may have a firmness factor sufficient to inhibit a pillowing effect after the stitching to not more than 0.03 inch. The outer insulating layer and an upper portion of the batting adjacent the outer insulating layer may be impregnated with a ceramic coating material

Barney, Andrea

Eilertson, Bryan

Siminski, Zenon

Whittington, Charles A

NASA Technical Reports Server

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(12) United States Patent (io) Patent No.: US 6,652,950 B2 
Barney et al. (45) Date of Patent: Nov. 25,2003 
THERMAL INSULATING CONFORMAL 
BLANKET 
Inventors: 
Assignee: 
Notice: 
Andrea Barney, Bedford, MA (US); 
Charles A Whittington, Gardena, CA 
(US); Bryan Eilertson, Huntington 
Beach, CA (US); Zenon Siminski, 
Bellflower, CA (US) 
The Boeing Company, Chicago, IL 
(US) 
Subject to any disclaimer, the term of this 
patent is extended or adjusted under 35 
U.S.C. 154(b) by 0 days. 
Appl. No.: 101072,793 
Filed: Feb. 6, 2002 
Prior Publication Data 
US 200310145773 A1 Aug. 7, 2003 
Int. C1.7 .................................................. B32B 5/22 
U.S. C1. ....................... 4281102; 4421262; 4281902; 
4281905 
Field of Search ................................. 4281102, 902, 
4281905; 4421262 
(56) References Cited 
U.S. PATENT DOCUMENTS 
5,038,693 A 811991 Kourtides et al. 
5,362,527 A 1111994 Harpell et al. 
5,436,042 A 711995 Lau et al. 
5,609,912 A 311997 Lackey et al. 
5,626,951 A 511997 Hogenson 
Primary Examineraexander  S. Thomas 
(74) Attorney, Agent, or F i r m 4 i P i n t o  & Shimokaji, P.C. 
(57) ABSTRACT 
The conformal thermal insulating blanket may have gener- 
ally rigid batting material covered by an outer insulating 
layer formed of a high temperature resistant woven ceramic 
material and an inner insulating layer formed of a woven 
ceramic fiber material. The batting and insulating layers may 
be fastened together by sewing or stitching using an outer 
mold layer thread fabricated of a high temperature resistant 
material and an inner mold layer thread of a ceramic fiber 
material. The batting may be formed to a composite stmc- 
ture that may have a firmness factor sufficient to inhibit a 
pillowing effect after the stitching to not more than 0.03 
inch. The outer insulating layer and an upper portion of the 
batting adjacent the outer insulating layer may be impreg- 
nated with a ceramic coating material. 
13 Claims, 3 Drawing Sheets 
https://ntrs.nasa.gov/search.jsp?R=20080007468 2019-08-30T03:20:11+00:00Z
U S .  Patent Nov. 25,2003 Sheet 1 of 3 US 6,652,950 B2 
U S .  Patent Nov. 25,2003 Sheet 2 of 3 US 6,652,950 B2 
FI 
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FIG. 3 
U.S. Patent Nov. 25,2003 
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US 6,652,950 B2 
T 2 0  
FIG. 5 
US 6,652,950 B2 
1 2 
THERMAL INSULATING CONFORMAL 
BLANKET 
GOVERNMENT RIGHTS 
of not more than about 0.03 inch. The stitching may use an 
outer mold layer thread of ceramic fiber material to stitch 
through the outer insulating layer and the batting, and an 
inner mold layer thread of ceramic fiber material as the 
s bobbin thread to engage the outer mold layer thread. 
In Yet another aspect of the invention, the insulation 
process after the stitching operation to reduce dirt, organics, 
and debris. The outer insulating layer and an upper portion 
10 of the batting adjacent the outer insulating layer may be 
impregnated with ceramic coating material to form a high 
temperature composite surface. 
This invention relates to thermal insulation used in high In a further aspect of the invention, a method of manu- temperature aerospace vehicle applications. The new ther- facture of a thermal insulation conformal blanket comprises mal insulating conformal blanket is constructed by incorpo- 1s the steps of fabricating a batting from alumina fiber material 
rating an initially generally rigid batting material with to a firmness factor that may inhibit a pillowing effect during surface layers fastened to provide a lower cost, reusable stitching to not more than about 0.03 inch. The batting may insulating device. then be covered with an outer insulating layer formed of 
Use of thermal insulating devices is known in the aero- ceramic fiber material and an inner insulating layer 
space industry. This subject has been extensively investi- 20 formed of ceramic fiber material, The batting and 
gated under NASA direction, as is evidenced in U.S. Pat. insulating layers may then be stitched together using an 
various batting materials, surface layers, and threads for to through the outer insulating layer and the batting, 
stitching the materials together. While these investigations and a lower temperature resistant inner mold layer thread as 
have produced notable results in materials development, a 2s a bobbin thread to form an insulation blanket device, The 
ture ceramic tiles for thermal protection on aerodynamic Finally, the outer insulating layer and an 
upper portion of said batting adjacent the outer insulating surfaces has not been discovered. 
A Primary impediment to the development of a less layer may be impregnated with a ceramic coating to form a 
expensive, as compared to ceramic tile, thermal blanket 30 high temperature composite surface, 
This invention described herein was made in the perfor- 
mance of work under NASACooperative Agreement NCC2- 
~ ~ ~ i ~ ~ ~ l  ~~~~~~~~i~~ and space of 1958 (72 stat, 435: 
42 U.S.C. 2457). 
9015 and is subject to the provisions of Section 305 of the device may be processed in a heat cyc1e 
BACKGROUND OF THE INVENTION 
No. 5,038,693. The patent the investigation Of outer mold layer thread resistant to high temperature damage 
for rep1acement Of high tempera- insulation blanket device may then be heat treated to remove 
product is the necessity that the Outer 'IKface Of any 
lation be 
These and other features, aspects and advantages of the 
present invention will become better understood with refer- smooth to avoid aerodynamic drag and 
associated aerodynamic heating. U.S. Pat. No. 5,626,951 
discloses materials that may be useful in developing a 
thermal insulating blanket. However, as in the case of other 3s 
stitched blanket designs, the problem of establishing a near 
ence to the following drawings, description and claims, 
BRIEF DESCRIPTION OF THE DRAWINGS 
net shape manufacturing process using existing materials is 
not solved. The batting in the prior art is not structured to 
easily manufacture a stitched blanket that inhibits the undes- FIG. 2 illustrates a perspective view of a portion of an 
ired resultant pillowing effect, as well as other surface 40 insulating blanket according to an embodiment of the inven- 
roughness features thus precluding its use on high tempera- tion; 
ture aerodynamic surfaces. FIG. 3 illustrates a cross section elevation view along 
can be seen, there is a need for a manufacturable, lines A-A in FIG. 2 according to an embodiment of the 
reliable, and affordable thermal insulating conformal blanket invention; 
for use in replacing expensive ceramic tiles used on aero- FIG. 4 illustrates a schematic representation of the stitch- 
space vehicles as an example. ing along lines B-B of FIG. 3 according to an embodiment 
a perspective view Of an 
according to an embodiment Of the invention; 
4s 
SUMMARY OF THE INVENTION 
of the invention; 
FIG. 5 illustrates a schematic view of the insulation 
An improved thermal insulating conformal blanket struc- so blanket with impregnated outer insulating layer and batting 
ture and manufacturing process according to the present according to an embodiment of the invention. - _  - - 
invention comprises a firm, rigid ceramic batting material 
having an outer and inner surface layer material which 
elements are joined by stitching. 
DETAILED DESCRIPTION OF THE 
INVENTION 
In one aspect of the present invention, an insulating 5s The following detailed description is of the best currently 
blanket device for use with aerospace vehicles comprises a contemplated modes of carrying out the invention. The 
batting formed from a ceramic fiber material such that the description is not to be taken in a limiting sense, but is made 
batting may be firm and generally rigid to inhibit pillowing merely for the purpose of illustrating the general principles 
during the processing of the blanket device. The batting may of the invention, since the scope of the invention is best 
be covered on all sides with an outer insulating layer 60 defined by the appended claims. 
resistant to high temperature. The batting and insulating Referring to FIG. 1, an insulation blanket 10 is illustrated 
layers may be fastened together by sewing or stitching. as a generally rectangular box construction fastened with 
In another aspect of the invention, the insulation blanket stitching 50 in a rectangular pattern. The insulation blanket 
device comprised of the batting, outer insulating layer and 10 in structure may be a firm, generally rigid (allowing 
inner insulating layer may have the batting formed to a 65 limited flexibility) construction that is conformable for use 
composite structure that may have a firmness factor SUE- on aerodynamic, high temperature surfaces of aerospace 
cient to inhibit a pillowing effect after the stitching operation craft as well as for use in other high temperature applica- 
us 6,652,950 B2 
3 
tions. Further, the material structure of the insulation blanket 
10 may provide a durable, resilient and thus reusable thermal 
insulating outer surface layer for high temperature protec- 
tion on aerodynamic surfaces. 
Referring to FIGS. 2 and 3, a portion of an insulation 
blanket 10 is illustrated that can have the structure of batting 
20 sandwiched between an outer insulating layer 30 and an 
inner insulating layer 40. Stitching 50 using an outer mold 
layer thread 36 and an inner mold layer thread 46 may be 
used to fasten the blanket elements together. 
The batting 20 insulating layer may be formed of ceramic 
fibrous material, such as alumina fibers or combinations of 
ceramic fibers of alumina, boria, silica and the like. In 
experiments conducted to fabricate insulating blankets, it 
was found that a generally rigid alumina batting of alumina 
fiber material was useful as a base for the stitching operation 
of blanket construction and provided the desired insulation 
properties. The generally rigid batting 20 may maintain the 
desired insulation blanket 10 shape during the sewing pro- 
cess thereby producing a uniform and consistent blanket. 
The generally rigid, as identified by for example a hardness 
test using a Shore Durometer type 000 with a minimum 
value of 90, batting 20 may also facilitate the assembly and 
fabrication of the insulation blanket 10. This batting 20 
structure facilitates cutting, trimming and shaping the bat- 
ting 20 for ease in conforming to necessary attachment 
locations on aerospace vehicles and for forming a uniform 
surface foundation for construction of the insulation blanket 
10. 
The batting 20 may be covered by an outer insulating 
layer 30 of a high temperature, approximately 2400" F., 
ceramic fiber material such as the trade name product 
NEXTEL 440 and an inner insulating layer 40 of lower 
temperature, approximately 1200" F., ceramic fiber such as 
E-glass both of which layers 30, 40 may be of a woven 
material construction. A high temperature ceramic thread 
fabricated of NEXTEL 440 may be used as the outer layer 
stitching material for the high temperature environment and 
a low temperature, approximately 900" F., ceramic thread 
such as S-glass may be used for the inner mold layer thread 
46. These examples reflect currently available materials; 
however, as can be understood by those knowledgeable in 
the art, other refractory materials may be used to construct 
the thermal insulating blanket. 
Referring to FIG. 4, the stitching of the insulation blanket 
10 may be accomplished by using known methods such as 
that used to construct the flexible insulation blankets used on 
the U.S. Space Shuttle. The outer mold layer thread 36 may 
serve as the machine needle thread and the inner mold layer 
thread 46 as the bobbin thread. Asquare stitch pattern of, for 
example, one-inch dimension was found by experiment to 
give desired results for fastening and surface uniformity of 
the outer insulating layer 30. 
Referring again to FIG. 2, the use of a firm, generally rigid 
ceramic fiber material as the batting 20 may result in a 
foundation structure for the fabrication process which pro- 
duces an insulation blanket 10 with a small thickness 
variation, approximately +/-0.03 inch and with a relatively 
smooth outer mold line variation 30 approximately +/-0.015 
inch. The use of the firm, generally rigid conformal batting 
20 structure may solve the problem associated with fabri- 
cation of aerodynamically smooth blankets. The insulation 
blankets 10 may be fabricated in larger sizes than ceramic 
tiles and may be more durable and flexible, thereby increas- 
ing reliability, affordability and reusability. 
Referring to FIG. 5,  the final step in the fabrication 
process for the insulation blanket 10 may be the impregna- 
S 
10 
1s 
2G 
2s 
30 
3s 
40 
4s 
so 
5s 
60 
65 
4 
tion of the outer insulating layer 30 with a ceramic coating 
material such as aluminaisilica, lanthanum phosphate or the 
like to form a high temperature composite layer 26. The 
insulation blanket 10 may also be processed through a heat 
cleaning cycle to remove dirt, organics and contamination 
resulting from the construction process to reduce particles. 
The outer insulating layer 30 with the impregnated compos- 
ite layer 26 may produce a relatively uniform, temperature 
resistant surface for the high temperatures experienced on 
the windward portion of an aerospace vehicle of up to 2200" 
F. 
It should be understood, of course, that the foregoing 
relates to preferred embodiments of the invention and that 
modifications may be made without departing from the spirit 
and scope of the invention as set forth in the following 
claims. 
We claim: 
1. A device for use in a thermal insulation system, 
a batting formed from a ceramic fiber material and having 
a hardness factor with a minimum value of 90 deter- 
mined by using a Shore Durometer type 000; 
an outer insulating layer and an inner insulating layer 
covering said batting wherein said outer insulating 
layer and an upper portion of said batting adjacent to 
said outer insulating layer is impregnated with a 
ceramic coating material to form an insulation blanket; 
and 
said outer insulating layer, said batting, and said inner 
insulating layer fastened together by stitching in a 
square stitch pattern of a one-inch dimension. 
2. The device as in claim 1 wherein an outer mold layer 
thread having a high temperature resistant quality is used to 
stitch through said outer insulating layer and said batting, 
and an inner mold layer thread is used as a bobbin thread at 
the inner insulating layer for said outer mold layer thread. 
3. The device as in claim 2 wherein said outer mold layer 
thread is a ceramic fiber material. 
4. The device as in claim 2 wherein said inner mold layer 
thread is a ceramic fiber material. 
5 .  The device as in claim 1 wherein said ceramic coating 
material is selected from one of an aluminaisilica and a 
lanthanum phosphate composition. 
6. The device as in claim 1 wherein said hardness factor 
of said batting is sufficient to inhibit a pillowing effect after 
fastening by said stitching resulting in a thickness variation 
of said insulation blanket of not more than 0.03 inch. 
7. The device as in claim 1 having a smoothness variation 
of approximately -0.015 inch to +0.015 inch and a surface 
thickness variation of approximately -0.03 inch to +0.03 
inch. 
8. The device as in claim 1 wherein after said sewing, said 
device is processed in a heat cleaning cycle. 
9. The device as in claim 8 wherein said heat cleaning 
cycle removes dirt, organics and debris to reduce contami- 
nation. 
10. The device as in claim 1 wherein said ceramic fiber 
material is selected from one of an alumina and an alumina/ 
silica material composition. 
11. The device as in claim 1 wherein said outer insulating 
layer is a ceramic fiber material. 
12. The device as in claim 1 wherein said inner insulating 
layer is a ceramic fiber material. 
13. A device for use in a thermal insulation system for 
elements of aerodynamic vehicles experiencing a high tem- 
uerature environment comprising: 
comprising: 
US 6,652,950 B2 
5 
a batting formed of a material selected from one of an 
alumina and an aluminaisilica fiber material; 
an outer insulating layer formed of woven ceramic fiber 
material and an inner insulting layer formed of woven 
said outer insulating layer and said inner insulating layer 
fastened together by stitching using an outer mold layer 
thread to stitch through said outer insulating layer and 
said batting, and using an inner mold layer thread of 
ceramic fiber material as a bobbin thread at said inner lo 
insulating layer for said outer mold layer thread; 
said batting has a firmness factor sufficient to inhibit a 
pillowing effect after said stitching resulting in a thick- 
ness variation of said insulation blanket of not more 
than 0.03 inch; 
ceramic fiber material covering said batting; 5 
6 
said batting having a hardness factor with a minimum 
value of 90, as measured with a Shore Durometer type 
000; 
said outer insulating layer and said inner insulating layer 
after said stitching is processed in a heat cleaning cycle 
wherein the quantity of dirt, organics and debris are 
reduced; 
said outer insulating layer and an upper portion of said 
batting adjacent said outer insulating layer is impreg- 
nated with a high temperature ceramic material to form 
an insulation blanket; and 
said insulation blanket having a smoothness variation of 
approximately -0.015 inch to +0.015 inch and a surface 
thickness variation of approximately -0.03 inch to 
+0.03 inch. 
* * * * *  


Thermal insulating conformal blanket

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