Beckerle, L. D.

English

NASA Technical Reports Server

March 4, 1969 JAMES E. WEBB 3,431,397 ADMINISTRATOR OF THE NATIONAL AERONAUTICS 
AND SPACE ADMINISTRATION 
HEAT SHIELD OVEN 
Filed Jan, 20, 1966 
21’ ‘27 
INVENTOR 
LLOYD D. B€CK€R6E 
https://ntrs.nasa.gov/search.jsp?R=19690018493 2020-03-16T18:47:53+00:00Z
1 
3,431,397 
HEAT SHIELD OVEN 
James E. Webb, Administrator of the National Aero- 
nautics and Space Administration, with respect to an 
invention of Llovd D. Beckerle. Los Alamitos. Calif. 
Filed Jan“. 20, 1966, Ser. k40.521,996 
U.S. C1. 219-347 2 Claims 
Int. C1. HMb 3/02,1 /OO; F24B 9/02  
‘ 
ABSTRACT OF THE DISCLOSURE 
A heating oven for uniformly distributing heat over 
the surface of an article of unusual or irregular configura- 
tion, said oven comprising a rigid body of laminated glass 
fiber sheets affixed to one another by adhesive lmeans and 
conforming to the shape of the irregular article to be 
heated. A heat reflective metal foil covers the surface of 
the rigid body to be disposed proximate the irregular 
article and protects the fiber glass structure from radiant 
heat from a plurality of heat lamps affixed at spaced 
points to the body and adjacent the heat reflective cover- 
ing which is disposed between the heat source devices 
and the laminated body. The heat lamps are disposed to 
uniformly distribute heat over the surface of the article 
and are affixed to the fiber glass body by thermally in- 
sulating and supporting socket means which also clamp 
the foil material to the body at spaced points. Between 
the spaced points an insulating air space is formed be- 
tween the metal foil and the glass fiber body to prevent 
heat absorption by the glass fiber body. 
The invention described herein was made in the per- 
formance of work under a NASA contract and is subject 
to the provisions of section 305 of the National Aeronau- 
tics and Space Act of 1958, Public Law 85-568 (72 
Stat. 435; 42 U.S.C. 4257). 
This invention relates to heating ovens. More particu- 
larly, it pertains to heat treating ovens for use with arti- 
cles of irregular or unusual configuration. 
Numerous products or parts therein must, prior to or 
upon completion of their fabrication, undergo a heat treat- 
ing process for a variety of reasons such as to dry paint 
coatings or ceramic portions, harden or anneal metals, 
or merely to test the product for heat insulation and en- 
durance purposes. A problem associated with this proce- 
dure is that of achieving an even distribution of heat 
over the surfaces of the product or article, this frequently 
being required regardless of the reason for which the 
heating is intended. An effective approach to the problem 
is to fabricate the oven itself in the form of the article so 
that heat source lamps on the oven’s internal surface 
may be equidistantly placed on it. When the article is 
particularly irregular in its configuration, however, as for 
example the external shape of a manned space vehicle, 
the cost of fabricating a specially shaped oven by con- 
ventional methods such as stretch pressing, spinning, or 
explosive forming becomes so great as to almost be pro- 
hibitive. Therefore, alternative fabrication techniques for 
specially shaped ovens have been practiced. One of these 
is the use of a plurality of oven sections which may be 
affixed to each other in a variable and interchangeable 
manner so as to “build” the oven to the desired shape. 
An example of the interchangeable section oven is shown 
in U.S. Patent No. 2,610,280 wherein a plurality of elon- 
gated trough-like lamp reflectors are hingedly connected 
to each other. By merely moving the troughs with re- 
spect to  one another a variety of oven shapes may be 
achieved, U.S. Patent No. 2,688,684 shows another form 
of the articulated section oven in which the numerous 
sections may be affixed to one another to conform to 
the product shape. The ability of such ovens to adapt to  
2 
numerous shapes, particularly those with flat or planar 
surfaces, makes their applications obviously flexible. Their 
effectiveness for uniform heat distribution is significantly 
reduced when used on product shapes having surfaces 
curved in a plurality of planes because the oven shape 
does not conform thereto. 
In view of the above, the present invention is directed 
to an oven and the construction thereof for evenly dis- 
tributing heat over the surfaces of irregular or  unusually 
shaped objects. Due to constructional features of the oven, 
it is economically feasible to build it to the specific shape 
of the product, thus insuring even heat distribution. This 
not only contributes to the quality and reliability of the 
product itself but enables greater flexibility in its de- 
15 sign. Briefly, it is constructed of a plurality of Fiberglas 
body sections formed by use of conventional molding tech- 
niques. The Fiberglas body is lined on the inside with a 
heat reflecting material such as aluminum foil, the latter 
being affixed to the body by the stand-off insulator of the 
20 lamp socket structures. Due to the tendency of the foil 
to lie in spaced relation from the Fiberglas at areas in- 
termediate the socket structures, there is provided a “dead 
air” space which, in addition to the foil insulates the 
body from the heat, thereby increasing high temperature 
25 capability of the oven over more extended periods of 
time. Additional features and advantages of the inven- 
tion are described hereafter for exemplary purposes in 
conjunction with and application to the heat shield por- 
tion of a space vehicle because of its unusual shape. Al- 
30 though the oven described and shown in the drawings is 
in the shape of such an object it is evident that the princi- 
ples and method of construction are applicable in the 
fabrication of other articles of unusual or irregular con- 
figuration. In view thereof reference is made to the ac- 
35 companying drawings in which like reference numerals 
designate like parts in the figures, and wherein: 
FIG. 1 is a perspective view of a typical oven section 
showing a side and an internal portion thereof. 
FIG. 2 is a sectional view through the plane 2-2 
FIG. 3 is a sectional view similar to FIG. 2, but 
showing the spacing between the laminated fiber body 
and the heat reflective covering affixed thereto. 
The aforementioned space vehicle requires, in its 
45 course of construction, a series of environmental heat- 
ing tests of construction, a series of environmental heat- 
ing tests in order to determine certain limitations and 
standards. The vehicle, includes an upper substantially 
conical portion and a lower somewhat cycloid shaped 
90 portion, is enclosed in oven sections which conform 
to these shapes. It is the lower oven section which, 
due to its irregular form, that the present example is 
particularly directed, Thus in FIG. 1 there is shown the 
bottom section of an oven which conforms to  the shape 
55 of a space vehicle heat shield. In fabricating such an 
oven section from a glass fiber material a supporting 
mold must first be constructed. This may be done in 
any of several well-known ways such as building of 
a wooden or metal form in the article (heat shield) 
00 shape, and evenly covering the form with plaster, clay, 
or other paste-like substance to form a mold which 
sets to a sufficient load supporting strength. In certain 
instances it may be feasible to build the mold directly 
over the article thus avoiding the necessity to construct 
O5 the form. This would depend, however, on the particular 
product, its shape, cost and other such factors. After 
the mold of the article has set, it is removed from the form 
and placed in stable position for receipt of the glass fiber 
layers. A coating of wax or other release agent is applied 
to the mold first in order to easily remove the Fiberglas 
after it has dried. The first layer of glass fiber material 
40 of FIG. 1. 
3,43 I, 397 
3 4 
is then positioned over the surface of the mold and scope of the invention. Thus it is apparent that materials 
coated with any conventional Fiberglas hardening and other than glass fiber cloth such as for example a plastic, 
bonding resin. A subsequent glass fiber layer is positioned may be used in forming the oven base. Similarly any 
thereover and the coating procedure repeated. The alter- of a variety of metal foils which have good heat reflective 
nate application of Fiberglas cloth or material and resin characteristics, such as gold or stainless steel, may be 
coating is continued until the desired thickness is achieved used in place of aluminum. Likewise, a heat reflective 
which, in the instant case, is approximately five-eighths paint or other coating could be substituted therefor. 
(%") inch. After the laminated layers of material have In view thereof, that which is claimed and desired to be 
cured, as in the form of body 3, it is removed from secured by Letters Patent is: 
the mold, inverted, and mounted on a supporting fixture 1. A device for uniformly distributing heat over the 
5, see FIG. 1. The body 3 of the oven may then be surface of an article of unusual or irregular configuration 
supported at appropriate structural points depending upon comprising: 
its overall configuration. Where, for example, its cross a rigid body of laminated fibrous sheets affixed to 
sectional form is that of a cycloid, as shown in FIG. 2, one another in unitary fOTm by an adhesive means, 
the fixture 5 may support it at a plurality of points 15 said body conforming to the shape of said article; 
such as by arms 7 which extend therefrom. a heat reflective covering over the surface of said 
Once the oven body has been positioned on the fixture rigid body to be disposed proximate said article, 
a plurality of holes 9 are drilled through the former said heat reflective covering being a metal foil 
so as to receive the lamp sockets 11 which are inserted material affixed to said body at spaced points thereon 
therethrough and electrically connected subsequently in 20 in spaced relation thereto and providing an insulat- 
any desired manner. The number of sockets and their ing space between said metal foil material and said 
particular arrangement in the oven will generally vary body; and a plurality of 
in accordance with the intended heat input and the partic- heat source means affixed t o  said body adjacent to  
ular shape of the oven. As shown in the drawings, uni- and spaced from said heat reflective covering by 
form heat distribution over the surface of a cycloid like 25 thermally insulating support means with said heat 
surface is best achieved by locating several banks of heat reflective covering disposed between said heat-source 
lamps 15 horizontally on the oven wall and by arranging means and said body, said heat source means being 
others in a radial manner at positions nearer the center. disposed to uniformly distribute heat over the surface 
Since the Fiberglas body absorbs heat and ordinarily of the article which conforms to the shape of said 
would decompose at high temperatures (above 500" F.) 30 rigid body. 
over extended periods, a heat reflective lining 19 is placed 2. The device for uniformly distributing heat over the 
over the internal surface 21 thereof. The lining may surface of an article of unusual or irregular shape as 
comprise a plurality of triangular or other appropriately recited in claim 1, wherein said rigid body is comprised 
cut sheets of thin (.005 inch thick) aluminum or other of laminated sheets of glass fiber material and said 
foil which are simply laid against the surface and formed 35 heat source means includes heat lamp means and sup- 
to the shape thereof by the application of hand pressure. porting socket means therefor affixed to said rigid body, 
As shown in FIG. 1 where the surface 21 is only par- said socket means also affixing said metal foil material 
tially covered, the sheets of lining 19 remain in fixed to said rigid body. 
relative position to the surface. Holes are punched through 
the sheets in aligned relation to  the body holes 9. The 40 References Cited 
sockets 11 are then inserted and the sheets affixed to UNITED STATES PATENTS 
socket means which act as clamp-like members. A ceramic 2,742,387 4/1956 Giuliani _ _ _ _  343-18 
nut 27 or other insulative means is affixed to the bottom 2,747,180 5/1956 Brucker _ _ _ _ _ _ _ _ _ _  156-242 X end of the sockets 11 to hold them in position. It is 45 2,765,248 Beech et 156-245 pointed out that the stand-off insulators 25 retain the 2,907,873 Smith 240-lo3 
foil covering against the internal surface 21 of the body 3,030,259 4/1962 Long _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  156-245 only at their point of contact with it and that in the 3,319,062 5/1967 Falk _ _ _ _ _ _  240--103 
area between the sockets the foil tends t o  raise %6 to 3,320,341 5,1967 Mackie _ _ _ _ _ _ _ _ _ _  156-245 % inch above the surface 21. This space (not shown) 50 
the body by conventional stand-off insulators 25 or 1,666,831 4/1928 pandolfo _ _ _ _ _  219-347 
thus acts as an insulator and assists in the prevention 
of heat absorption by the Fiberglas body, thus increasing 
its ooerational life. In order to increase oven life even 
FOREIGN PATENTS 
982,957 2/1965 Great Britain. 
still further an insulating material may be placed inter- 55 
mediate the body and the aluminum foil. BARTIS, P,.inza,.y Examine,.. 
U.S. C1. X.R. It should be understood that the present disclosure and accompanying figures relate only to a preferred embodi- 
ment of the invention and that it is intended to  cover 126-270; 156-245; 219-357, 461, 535; 264-136; 
all changes and modifications of the above example 350-288 
which do not constitute departures from the spirit and 60 


Heat shield oven

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server