Test chamber for determining decomposition and autoignition of materials used in spacecraft under controlled environmental condition

Bryan, C. J.

Evans, F. D.

Springfield, C. L.

English

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I t l  1'1 Y TO 
A I T N  OF. G p  
TO: 
F ROM I 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ' 
WASHINGTON, D.C. 20546 
~ S I / ~ c i e n a f i c  6 Technical 1nfomat;ton Division 
Attention: Mibe Winnie M e  Morgan 
~ ~ / ~ f f i c e  of Assistant General Counsel for 
Patent Matters 
I 
SUBJECT: Announcement of NASA-Owned U. S. Patents i n  STAR 
I n  accordance with the procedures agreed updn by Code GP 
and Code USI, the attached NASA-owned U. S. Patent is being 
forwarded fjor abstracting and announcement i n  bJASA STAR. 
The following infomation is prwided: 
U. S. Patent No. 
Government or 
corporate Employee 
Supplementary Corporate > . 
Source (if  applicable) t HA - 
NASA Patent Case No. t 
NOTE - If  t h i s  patent covers an invention made by a corporate 
employee of a NASA Contractor , the following is applicable: - 
yes 0 NO Q' 
Pursuant t o  Section 305(a) of the National Aeronautics and 
Space Act, the name of the Administrator of NASA appears on 
the  f i rs t  page of the patent; however, the name of the actual 
inventor (author) appears a t  the heading of C o l m  No. 1 of 
the Specification, following the wrds  a. . . w i t h  seapect t o  
- 
N 
0 
~ 1 1 - 2 8 6 2 9 "  
Enclosure 
I 
(CATEGORY) 
1 
https://ntrs.nasa.gov/search.jsp?R=19710019153 2020-03-17T03:14:14+00:00Z
PATENTED MAY 1 8 1971 
United States Patent 
1721 inventors Fred D. Evans 
Oddo; 
Carlos L. SpPin&eld. Titusvine; Coleman 
9. Bryan, Memitt Island, Fla. 
[21] AppI. No. M5,971 
[22] Filed July 30,1969 
[45] Patented May 18,1971 
j73] Assignee The U ~ t d  States of America as reprwntced 
by the Admimistrator of the FdatPtiond 
Aemmutirs md Spaee Adminisfragon 
(541 AUTOIGM3ON TEST CELL 
1 Claim, 3 Dmwing Figs. 
[ 5 2 ]  U.S. C1 ................................................. 73/15, 
731432 
[5 11 bt .  el .................................................. Gonn 25/00 
[50 1 Field of Search ............................................ 731 15, 432 
f561 Wefemnws Cited 
UNITED STATES PATENTS 
3,049,913 811962 Hunt ............................ 731432 
3,238,784 311966 Dorsey et a! .................. 731425 1 
................. 3,592.41 7 12/1966 Nayden sf al 73/15 
................... 3,298.220 111967 Stone et al. 15:~s 
................... 3,396.584 811968 Badin er al. 7314.14 
P n ' m r y  E.rammer-James J. Gill 
Assrsrant Examiner-Herbert Goldstenn 
Arrorneys-James 0. Hamell 6 T McCn) 
m S W C T :  A chamber for analy~mg test \antpL~s 3C matera 
als, such as used in spacecrafes, undcr cer"iarr pr.)drtcrrni$~ed 
environmentd condi~ons rn order to detemlnc autoignrtaoei 
temperatures and degree of decompsition 1s casntroilcti at- 
mbspheres. The apparatus includes av e i o n g ~ e ~ d  herrnel:c?iij 
sealed cylindrical chamber which has a olu~alnty of coupl~tags 
carned thereon. A vacuum pump, a source ef g ~ s ,  a bribhicr 
system which bubbles through a rnercdry %th, a dab+: ad 
other various items may be coupled to the c ~ u g l s ~ ~ g s  rn or Irr 
to produce predetermined envrronr~cniai cirndltrcns wati'llrc 
the chamber The chamber IS aim provnded w ~ t h  a V I W W ~ ~ ?  
port and a tRemmoupled probe for measbring the temp? 
ture of the test sample. 
3,578,756 
I 2 
AUTOIGNITION TEST CELL thereof, respectively. The chamber may he cor-rsr~;ucred of any 
This invention described herein was made by enlployees of suitable pipe, and in one particular example i t  has a 3 
?he United States Government, and may be manufacturcd and inside diameter. A cup-shaped lwttorn 13 is scrcwed on chc 
used by or for the Government for Governmental purposes threaded portion 11 of the chamber 110 :.ind Bias an O-ring 14 
without the payment of any royalties thereon or therefor. 5 carried therein for producing a hermetically se:l!cd re!atEer~- 
This invention relates to an apparatus for analyzing test ship. Diametrically opposed protruding prc~jecrions 15 c.~nend 
samples, and more particularly to an apparatus wherein the outwardly from the bottom for providing a ccnvenieni mcan?s 
environmental condition can be readily controlled during the of securing the test cell within a suicablc jig inor sht;wn). 
testing procedure. A hermetically sealed top assembly, generally designated b> 
One of the most dangerous and conscious problems encoun- the reference character 16, is provided f ~ i  cEosEl?g the fop 
tered by persons working in confined areas Is fire. This is espe- the pennitring into interior ~h~ 
cially true of astronauts in spacecrafts, as well as personnel top assembly includes a cup-shaped lop cover 17 has in-  
aboard ships and the like. While the autoignition temperature ternal .threads so such can be screwed on ellreads 12 
of most materials is known under normal atmospheric condi- , ca,-+d on top of the ,-hambe,. 10. positioned beween the 
tions, such is frequently not hewn in certain environmental of the chamber and a flat top portion 18 of the Ccp cover 17 
conditions as one would encounter in space vehicles. is an O-ring 19. The top portion 18 of the top cover 17 has a17 In view of the rather recent development of the various 
opening 20 in the middle thereof through vvhiclz 21 thermocotl- 
synthetic fabrics. it is important to provide a simple and con- 
venient method of testing samples of such material in order to pied probe 21 extends for measuring the temperature of a test 
determine the autoignition temperature in various environ- 20 sample 22 carried on the bottom cover 13. Leads 23 and 24 
conditions, as well as to determine if any decomposi- which are connected to the thermocoupied probe extend 
tion of the material takes place. through the opening 20 and a silicon rubber gasket 25 to a 
accordmce with the present invention it has been found plug 26 carried on the exterior of the test ceEi vdhich can be 
that samples can be analyzed to determine the autoignition readily connected to any suitable meter fiss inclicaring tern- 
temperature, and if decomposition takes place by using an au- 25 perature. 
toignition test constructed in accordance with the present Positioned on top of the silicon rubber gasket 25 is a giasc 
invention,  hi^ autoignition test cell includes the following cylindrical view port 27. Carried on top d the view port 27 is 
basic (1 ) an elongated cylindrical chamber, (2)  a another silicon rubber gasket 28 upon which a metallic view 
hemetically sealed bottom screwed on one end of the cylin- port attaching plate 29 is carried. It is noted that the view port 
drical chamber, (3 )  a hermetically sealed top assembly carried 30 attaching plate 29 and the silicon rubber gaskets 25 and 28 
on the chamber which h a  a transparent portion for permitting have holes in the center portion thereot which correspond to 
viewing of the interior of the chamber, (4)  a thermocoupled the hole 20 in the top cover for permitting viewing within the 
probe positioned in the chamber adjacent the test sample, (5)  interior of the test chamber. All of the members fomning the 
a plurality of couplings carried by the chamber providing com- 35 top assembly are circular in shape. Circurnfercntialiy spaced 
rnunications with the interior of the chamber, (6) a vacuum holes 30 are provided adjacent the perimeter of the view port 
pump coupled to one of the couplings for evacuating the test attaching plate 29 for receiving bolts 31 which are scrcv<ed in 
cell prior to running a test on the sample, ( 7 )  a source of gas, corresponding threaded holes in the top cover fgr drawing the 
such as oxygen, coupled to mother coupling for selectively view port attaching piate 29 thereto. When the l>oits 31 tire 
producing a particular environmental condition within the 40 drawn tight the top asembly 16 is herlnclica{ly scaled. 
chamber, (8) a mercury bubbler coupled by means of a tube pressure exerted on the top of the silicon-conrro!ied rubbcr 
to another coupling for maintaining a constant predetermined gasket 25 is great enough to completely wjres 23 llnd 
pressure within the chamber, and (9) a hermetically sealed 24 extending therethrough in order to prevent air from escap- 
septum coupled to one of the couplings so that gas samples ing, 
can be taken from the interior of the chamber by means of a 45 A plurality of couplings, generally design:iled by elre: 
hypodermic syringe. Neat can be the test reference character 32, are circumferentially spaced in the 
and chamber by immersing the chamber in a liquid heat bath. wall of the chamber 10 for providing co~munkca~i,ons the 
nus, a test sample can be to various temperatures in interior thereof. A vacuum pump 33 is iltlachcd by means 
a particular environment. line 34 to a control valve 35 which is, in turn. coupled to crnc 
accordingly, it is an important object of the present inven- 50 of the couplings 32 so that the chamber can be evacuated. 
tion lo provide an autoignition test cell for determining the au- source of gas, such oxygen tank 36, is coupled tubing 37 
temperature of various in a predetermined through a valve 38 to another 32, 4, pres- 
environmental condition. 
Another important object of the present invention is to pro- sure gauge 39 is coupled to still another valve 32 for indicaiierg 
vide a simple and eficient test cell wherein test samples can 55  the pressure within the chamber. 
be analyzed and decomposition of the test samples can be In order to maintain a constant pressure within the chamber 
readily checked by use of a hypodermic syringe. during a test one of the coupling members 32 is coupled 
still importdnt oj,jcct o~ prc;scnl iii. ,  i.ntinn is to thmugh a valve 40. a bubbler tube 41, a viewing coupler 42. to 
a simple and ef,icient test cell wherein a prcdeter- a tube 43 which is immersed in a mercury bath 44. By allewing 
nincd pressure can be maintained the cell as 60 the gas from the chamber 10 to bubble through the msrceary 
perature is varied during a test. bath 44. s the pressure within the chamber is increzsed r;ucF. 
other objects and atjvantagcs of this invention will become maintains a constant pressure within the chamber. T h e  prcs- 
more from a reading of the following derailed sure at  which the chamber is maintained is controiled by the 
description and appended claims, into conjunction with depth that the tube 43 is immersed within the mercury. 
the accompanying drawing wherein: 65 It is also frequently desired during a test to ask<: sarnpnes of 
FIG, 1 is a top plan view of an autoignition cell constructed the gas within the chamber 10 SO that such can be analyzed to 
in accordance with the present invention, determine if the test sample is outgasing. rhls  is accom- 
FIG. 2 is a side elevational view taken along line 2-2 of FIG. plished without intermpting the test by using a h)~podernkc 
1, and syringe and inserting such through a hermetically sealed sep- 
WG. 3 is a cross-sectional elevational view illustrating the 70 tum 45. The septum is carried on the end of a coupling 32 ky 
intefior of the autoignition test cell raken along line 3-3 of means of a cup-shaped lug 46, which is threadcd on the end of 
FIG. I. the coupling, and has an opening in the end thereoffor provid- 
Referring in more detail to the drawing, the apparatus in- ing access to the septum 45. The septum 45 is ccuns?eucted of 
cludes a rigid elongated cylindrical chamber 10 which has any suitable material that will seal itself after ;kc l~ypoder~nic 
threaded portions 11 and 12 adjacent the bottom and top 75 syringe is removed therefrom. 
r,,>r L ~ ~ I I  DL g i p p / l J  to the chamber and te\t sample by any 
LIIL *hie I ?,-~ri w4.n i b  d hot ltquld metal bath whlch h a  a low 
tnii:~ng ' l o x  chi r a n  su i  h as wood> metal. whlch melts at ap- 
psoxiniatr y i403t I he hdmber  1s usually placed in a j ~ g  by 
m L a . i \  r 1 "IL proJcrtioni 15 cdrrled on the bottom cover 13, 5 
-<"L. h ,\ 1 1  & n ~ r k d  p rt~allq *!thin the metal bath Any 
zucr, bli. i.rc't, 5 1 t-ic r hov\ n )  c.m be used for closely regulating 
3nd -i n- io l '  ng ih: tdmp~razure of the liqurd bath When it ls 
ii~sired *e i i ~ L i l y  re . t ~ . ~ t  \ample first the top 11d assemblq 14 15 
~ r n j ) ~ e ( !  ii-i\in \he es<t cell and thc chamber 10 and the top I d  10 
a k i ~ r ~ b i j  GLFG h ) * k  pl ~ L c C P  in an oven at 300" F tor at least an 
hob.: \o a i  to bit 1-11 rt the chamber The chamber and top as- 
\ ~ - " a ? j  arc f k a  r2 mo~ed and placed nn a clean enbrronment 
211J li1cwd 3 ~ a a 1  below (60'1; The tlme requ~red to c w l  1s 
apprL?~ii"drtly ' hour The rest sample, whrch may be a plece 15 
of Obrzi that 15 to he used In a spacecrafr rs placed In the 
~ h ' a n l b  $0 on tne nottom cover 23 with the thermocouple 21 
'"a itini*~r mit i \  the ~ente :  thereof 
T3-e top ,.iwrnbiy IS then placed on the chamber BO and 
.. 3 \L 35 1s o p e o ~ d  ailowlng the vacuum pump 33 to evacuate 20 
rht chGlq.ines 10  apnroxirnatelq 0 2 p s I a The vahe 35 is then 
L osed dn.~  vaivz 38 14 opened alioivlng the oxygen from tank 
36 rc flew ehAough line 37 Into the chamber until the pressure 
t~dihes a~prnuasrrdrcly 17 p s I s. T h ~ s  pressure reading 1s ob- 
s ~ r g c d  ,in khr prebsJre gauge 39 -Phe test cell is then allowed 25 
to id Y\Y approxzrliltcly 30 mlnutes with ali of the valves 
LVOILJ e q ~ 3 p t  t h t  connected to the pressure gauge 39 so as to 
-:*,lnlille it there are any leaks there~n The pressure gauge 
reLtd ilg ih~baid rsm-uslzn constant for t h ~ s  perlod If it is desrred 
to t i ~ ~ h e  mi. i9rht t c ~  at dpp~ox~mately 150°, then the chanlber 30 
c p14ccd iri t Matel bath and the valve 40 ~nterposed In line 41 
Y intni:cl Xc vw~qta in  the constant pressure w ~ t h ~ n  the 
~ r ~ ~ r i b e r  Ry p~-,it~onrng the rube 43 within the nlercury bath 
44 ar ic i  Y n s u  q ~ % ~ c o u s l v  obsemng the pressure gauge 39 ~t can 
hi ii~te*rli n ~ d  L + ~ C  e > . ~ c t  depth at wh~ch the tube slrouid be 35 
~ m ~ ~ ; z ~ i ~ c m i i ' n  18: 01uer:o rnasnlaln 16 5 p s i a kftei tne tempera- 
Tale .! \hi le\i ~ r r i ~ ~ t t  22 !:as reached 150" and remains there 
91 1 it l i t e ~  or more than i 5  mrnutc\ dn in'tiytl- 
\,a-,-lc ii * ? i ( a  sf the gai lk~ihrn the ~hamber  by msertlng 
a \ 2 x 1 ~ ~  ri ac s\rcfieb through the \eptum 45 and wirhdraalng 40 
b & s  kierk?-~)" " il* \ample temperature rcrnanns dt 150" plus 
.rj minus 5" POT dppmxlmateiy 5 hours, and then another 
arlalyilcal sample is tadten wrth the hypotlermrc syrmge When 
1 a *  hie< r ,I CL , r i )  'L 'i sampte ira an c,;cygen cnvironmenl at a 
la;:a,r it.sl)t*ature the b~h"oer  iial'ic 4@ 15 closed and the 45 
e'i, mser 110 L pILxced rn a -eta1 bath n h i ~ h  as a low rneltlng 
a,ioj sucn ds V"IDC>~L, metal therein, and the temperature of 
s ?c-eaiec~ to eappro~clmdrelg 400°F The bubbler valve 
fO !< opcned - 6 .  a. :.it Taarntarn a constant pressure of 16 5 p s a 
r r 1 t . i  t r e  ~ l ~ a n i b ~ s  Normally, It 15 deslred that the heating 50 
,~ i  rs "i",9k that ~ h r  rample temperature reaches 400" plub or 
r q i -  u> 19" 1- In 5 rc 25 minutes The test ccll remains In the 
",A:I vilh *Lit tsubblcr calve 40 open dnd the sample tempera- 
'a a, .I 100' yCiii a x  nrntis 10" F for 5 mlnutcs Analytical 
is,:.p 2 .  xi .dkcs 34 Lse of a hypodermic aynnge be~ng in- 55 
3erted thwugh tile septum 4.5 at various times After the 
d,,sr:d xsusnber of ,tnalyt~cal samples have been taken at the 
400" level all of the valves are closed and the chamber 10 is 
removed from the metal bath. The sample can then be 
removed from the chamber for physical inspection to deter- 
mine if any deterioration of such took place. One reason for 
taking the gas samples during the test is to determine if there is 
any outgassing at the various temperatures from the sample. 
The above analytical test is merely an example of one such 
ses: wirich could take place within the chamber, and it is to be 
understood that many different tests could be performed, and 
gases other rhan oxygen could be inserted within the chamber 
to create the environmental condition. 
We claim: 
I. An apparatus for analyzing a test sample from materials 
such as used in spacecrafts under certain predetermined en- 
vironmental conditions comprising: 
A. an elongated cylindrical chamber havino threaded ends; 
B. a hermetically sealed bottom having acihreaded p r t ion  
engaged with one of said threaded ends of said cylindrical 
chamber; 
C. said test sample adapted to be positioned in said cylindri- 
cal chamber on said hermeticaliy sealed bottom; 
D. a hermetically sealed top assenibly including; 
1. a top cover having a threaded portion engaged with the 
other threaded end of said cylindrical chamber; 
2. an opening in the center of said top cover; 
3. a first gasket posi~ioned on said top cover and having 
an opening therein; I 
4. a piece of glass positioned on top of said first gasket; 
5. a second gasket positioned on top of said piece of glass 
and having an opening therein; and 
6. an attachment plate engaging said second gasket arid 
detachably connected to said top cover and having an 
opening therein; whereby said openings in said top 
cover, said first and second gaskets and said at- 
vachmeni plan provide a view port for inspecting said 
resl sample; 
E. a thennocoup;cci probe having one end engaging said test 
sample and the other end ex;ending through said first 
gasket; 
F. a plurality trf couplialgs carried by said cylindrical 
chamber for providing cummiinication with the interior 
thereof; 
6. a vaculirn pump coupled to one of said couplings for 
evacuating cylindrical chamber prior to running a 
rcst oil said lest sample; 
H. a source of gas coupled to another of said couplings for 
selectively producing a particular environmental condi- 
tion within said cylindrical chamber; 
6 .  a mercury b:rth: 
J. a rube having one end coupled to another of said 
couplings and the other end immersed in said mercury 
bath for inaintaining a constant predcterrnine pressure 
within said cylindrical chanter ;  and 
K. means for heating said cylindrical chamber, whereby said 
test sample can be exposed to various temperatures in a 
predetermined environment. 


Autoignition test cell Patent

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