Low thermal loss piping arrangement for moving cryogenic media through double chamber structur

Yager, S. P.

English

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NOTICE 
The invention disclosed in this document resulted from 
P.t;@eare’k In a@rrsnautical and apaee aetlvitiea p e ~ f o ~ r n e d  und@r 
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The invention is owned by NASA and is therefore available for  
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To encourage commercial utilization of NASA-owned inven- 
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the invention while the patent application is pending in the U.S. 
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after issuance of the patent to NASA. If commercial use  of the 
invention does not occur during this period, NASA may grant a 
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Address inquiries and all requests for licenses to Assistant 
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66/254 
AWARDS ABSTRACT 
Inven to r t  Stephen Po Yager 
Contractor :  Jet Propuls ion Laboratory KNP- @8Z7+2 
March 3 ,  1967 
P I P I N G  ARRANGEMENT 
THROUGH A DOUBLE CHAMBER STRUCTURE 
The pr imary o b j e c t  of the inven t ion  is t o  minimize 
thermal losses when p i p i n g  cryogenic  media i n  and o u t  of an 
i n n e r  chamber, surrounded by an o u t e r  chamber a t  guard vacuum. 
A s t r a i g h t  f l e x i b l e  condui t  1 2  (F igu res  1 and 2 )  
is  employed. I t  ex tends  from a source of cryogenic  media 
(not  shown) t o  an i n n e r  chamber 5 through an o u t e r  chamber 8. 
A s u b s t a n t i a l  p o r t i o n  of condui t  1 2  through the chamber 8 is 
surrounded by a thermal i n s u l a t o r  13 which is  used t o  
the rma l ly  isolate and suppor t  the end 12a of condui t  1 2  t o  
t h e  w a l l  6 of t h e  i n n e r  chamber, A hollow tube 12x is  
c o n c e n t r i c a l l y  mounted about  condui t  1 2  t o  de f ine  an annu la r  
space 1 6 ,  which is i n  communication w i t h  . the environment i n  
chamber 8, A t  a p o i n t ,  e x t e r i o r  t o  the o u t e r  chamber, tube 
12x is welded t o  condui t  12, A bel lows 20  is u t i l i z e d  t o  
f l e x i b l y  seal the condui t  12 t o  w a l l  7 o f  o u t e r  chamber 8, 
The communication between a n n u l a r  space 16 and chamber 8 
i n s u r e s  t h a t  the environment about  the condui t  12 is  that 
of the  guard vacuum of the o u t e r  chamber, while t he  bellows 
20 provides  t h e  f l e x i b i l i t y  f o r  the  condui t  to expand or 
c o n t r a c t  as a func t ion  of temperature  changes. 
p re sen t  inveuntion is inc reased  efficiency i n  @ping cryogenic  
media through a double chamber s t r u c t u r e .  
The major b e n e f i t  o'r advantage realized with  the 
May 27, 1969 JAMES E. WEBB 3,446,387 
ADMINISTRATOR OF THE N A T I O N A L  AERONAUTICS 
A N D  S P A C E  ADMINISTRATION 
PIPING ARRANGEMENT THROUGH A DOUBLE WALL CHAMBER 
Filed l a y  17, 1967 
-1 2 b 
FIG. I 
F IG.  2 
INVENT0 R. 
STEPHEN I? Y A G E R  
By 9L‘% 
,y. W 2 ’  d ATTORMEYS 
3,446,387 United States Patent Office Patented May 27, 1969 
1 
3,446,387 
PIPING ARRANGEMENT THROUGH A 
DOUBLE WALL CHAMBER 
James E. Webb, Administtator of the National Aero- 
nautics and Space Administration, with respect to an 
invention by Stephen P. Yager, Whittier, Cam. 
Filed May 17, 1967, Ser. No. 640,784 
Int C1. B65d 25/00 
US. CI. 220-14 5 Claims 
ABSTRACT OF THE DISCLOSURE 
A low loss double wall piping arrangement in which 
a straight through conduit which is capable of linear 
expansion and contraction is used for piping cryogenic 
media or the like into an inner high vacuum chamber 
through an outer chamber maintained at guard vacuum. 
An insulator with low thermal gradient inflexibly sup- 
ports the end of the conduit extending into the inner 
chamber, while a bellows flexibly seals the other end of 
the conduit through a concentric tube to the outer wall 
of the outer chamber. The conduit and the concentric 
tube define an annular space about the conduit so that 
the environment about the conduit is that of the guard 
vacuum of the outer chamber. 
ORIGIN OF THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, Public Law 85-568 
(72 Stat. 435; 42 U.S.C. 2457). 
BACKGROUND OF THE INVENTION 
Field of the invention 
This invention relates to a liquified gas piping arrange- 
ment and, more particularly, to improvements therein. 
Description of the prior art 
Various devices are presently known for piping cryo- 
genic liquids to a storage chamber in which they are to be 
maintained at a very low temperature. Similarly, in cryo- 
genic applications, various piping arrangements are em- 
ployed to inject cryogenic media, either liquid or gas into 
a high vacuum chamber for cooling purposes. Generally, 
the high vacuum chamber is an inner chamber, sur- 
rounded by an outer chamber acting as a guard vacuum. 
The function of the outer chamber is to serve as a thermal 
barrier. The cryogenic media must be piped into the inner 
chamber through the outer chamber. In the prior art, in 
order to allow for expansion and contraction between the 
chambers, a curved conduit is generally employed. 
Though such an arrangement solves the problem of 
relative expansion and contraction between chambers, the 
increased length of the conduit results in a bulky and 
cumbersome arrangement and lowers the overall system’s 
efficiency. As a result, such an arrangement cannot be 
employed satisfactorily where the system’s efficiency i s  
of primary importance. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is therefore a primary object of the invention to pro- 
vide a new arrangement for piping cryogenic meda into 
an inner chamber through an outer chamber. 
Another object is the provision of a low loss double 
wall feed through arrangement. 
A further object is to provide an efflcient ammgement 
for piping cryogenic media through a double wall cham- 
ber without resort to a curved conduit. 
2 
These objects of the invention are achieved by provid- 
ing a straight conduit which extends from an exterior 
source to an inner chamber through an outer chamber 
surrounding it. A substantial portion of the conduit ex- 
tending through the outer chamber is surrounded by an 
insulator of a low thermal gradient, thermally insulating 
the conduit from the environment in the outer chamber. 
The upper end of the insulator is integral with the 
conduit, while the lower end is integral with a flange, 
thus sealing and supporting the conduit extending into 
the inner chamber. 
A hollow elongated tube, is mounted concentric with 
the conduit and surrounding it, with the upper ends of 
both tubes, exterior to the outer chamber, being integral 
15 with each other, so as to form an annular space about 
the conduit, which is in communication with the outer 
chamber. A flexible member such as a bellows has one 
end fastened to the outer chamber wall while the other 
end is fastened to the open end of the hollow elongated 
20 tube surrounding the conduit. Consequently, the conduit 
assembly is flexibly sealed with respect to the outer cham- 
ber thereby providing the necessary flexibility for ex- 
pansion or contracting of the chambers with respect to 
one another. The outer chamber is maintained at a guard 
25 vacuum so that, except for the portion of the conduit 
covered by the insulating material, a major portion of the 
exterior surface of the conduit is maintained at the guard 
vacuum environment of the outer chamber thereby 
minimizing cmdbction losses therefrom. 
The novel features that are considered characteristic 
of this invention are set forth with particularity in the 
appended claims. The invention will best be understood 
from the following description when read in connection 
with the acco,mpanying drawings. 
30 
35 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIGURE 1 is an enlarged cross-sectional view of the 
piping arrangement of the present invention; and 
FIGURE 2 is a combination side and cross-sectional 
view of the piping arrangement of the present invention, 
actually reduced to practice. 
40 
DESCRIPTION OF THE PREFERRED 
45 EMBODIMENTS 
Referring to FIGURES 1 and 2, there is shown a 
straight central conduit 12, extending from an external 
5o source to an inner chamber 5 formed by a wall 6. The 
conduit 12 may be thought of as having an end 12a which 
extends into the inner chamber 5 and an opposite end 
12b which is assumed to be connected to the source of 
cryogenic media. A wall 7 surrounds wall 6 and the 
55 space therebetween defining an outer chamber 8, through 
which conduit 12 extends from the outside to the inner 
chamber 5. A substantial portion of conduit 12, extend- 
ing through outer chamber 8 is thermally insulated by 13. 
Near end 124 a flange 14 is attached to the thermal insu- 
lator 13. Flange 14 is assumed to be attached or secured 
In addition to central conduit 12, the piping arrange- 
ment of the present invention includes a second hollow 
elongated tube 12x which is mounted concentric with 
65 and surrounds the central conduit 12. Outer tube 12x 
surrounds the central conduit 12 within the outer cham- 
ber 8, as well as a portion thereof extending out of the 
chamber 8. Thereat, the conduit 12x is attached, such as 
by welding, to the central conduit 12 to define an annular 
spacing 16 about the central conduit. The annular spacing 
16 is in communication with the space in the outer cham- 
ber 8 through opening 18. 
6o to wall 6 thereby enclosing the inner chamber 5. 
3.446,387 
3 
In practice, the inner chamber 5 is maintained at a very 
high vacuum, with the cryogenic media piped therein. To 
minimize thermal losses, the outer chamber 8 is main- 
tained at a guard vacuum to create a thermal barrier 
about chamber 5 and thereby reduce the thermal losses 
of the system. The means for producing the vacuums in 
the two chambers are deleted from FIGURE 1, since 
such means are well known in the art and are not deemed 
as pari of the invention disclosed herein. 
In addition to the foregoing described parts of the 
piping amendment of the present invention, the arrange- 
ment includes a flexible member, such as a bellows 20, 
having one end thereof secured to the outside of conduit 
12x near end 18, while the other end thereof is secured 
to a flange 22 which is in turn used to attach the bellows 
to wall 7, which defines the outer chamber 8. 
The bellows provides the necessary flexibility for the 
relative expansion and contraction of the two chambers 
with respect to one another. 
While the outer conduit 12x is used together with bel- 
lows 20 and flange 22 to secure the central conduit 12 
with respect to the other chamber 7, the annular space 16 
formed by conduit 12x together with the central con- 
duit 12 provides a guard vacuum environment over all 
of the exterior of conduit 12, not covered by the thermal 
insulator 13. As a result, thermal losses due to conduc- 
ton from the central conduit 12 as the cryogenic media 
passes into inner chamber 5 are held to a minimum. It 
should be appreciated by those familiar with the art 
that with the arrangement as hereinbefore described, the 
conduit 12 is a straight conduit extending from the out- 
side through chamber 8 to chamber §. Its length need 
only be enough to extend through the outer chamber 8. 
Thus, by minimizing its length, the system's efficiency is 
increased. 
FIGURE 2 represents a combination side and cross 
sectional view of a piping arrangement actually reduced 
to practice. In FIGURE 2, elements like those shown in 
FIGURE 1 are designated by like numerals. In FIGURE 
2, numeral 24 represents a point at which the thermal in- 
sulator 13 is welded to the exterior surface of the cen- 
tral conduit 12 to provide the inner chamber vacuum 
seal-off. As seen from FIGURE 12, the end of the bellows 
20 to be coupled to the outer tube 12x near end 18 is pre- 
ferably welded to a flange 25 which is in turn fastened 
to a flange 26, welded about the periphery of outer tube 
12x near opening 18. Any conventional fastening means 
such as a screw 27 may be used to fasten flanges 25 and 
26 to one another, with a copper alloy seal 28 inserted 
therebetween. The function of seal 28 is to seal the in- 
side environment of bellows 20 from the outside environ- 
ment thereof which is at the guard vacuum of outer 
chamber 8. 
There has accordingly been shown and described herein 
a novel piping arrangement, by means of which cry+ 
genic media or any other media to be maintained at very 
low temperatures may be pumped or injected into an in- 
ner chamber through an outer chamber. The arrange- 
ment incorporates a straight conduit of minimum length, 
in order to increase efficiency. The arrangement provides 
flexible means about the conduit so that the straight con- 
duit may be securely fastened to both the outer and in- 
ner chambers and yet provide sufficient flexibility for the 
relative expansion and contraction of the two chambers 
with respect to one another. Such flexibility is provided 
by the bellows 20 and the particular arrangement in which 
the conduit 12 is supported within the outer chamber. 
Also, the use of a thermal insulator to isolate the con- 
duit, extending through the inner chamber, as well as 
the use of an annular space about the conduit to main- 
tain it at the guard vacuum environment of the outer 
chamber, greatly account for the minimizing of thermal 
conduction losses of the piping arrangement. It is ap- 
preciated that those familar with the art may make modi- 
fications in the arrangements as shown with departing 
from the true spirit of the invention. 
5 
10 
15 
20 
25 
30 
35 
40 
45 
60 
55 
60 
65 
70 
76 
4 
I claim: 
1. An arrangement for piping cryogenic media into a 
first chamber defined by an inner shell and surrounded by 
a second chamber defined by an outer shell from a source 
of gas through aligned openings defined in said first and 
second shells comprising: 
an elongated straight central conduit having first and 
second ends, the first end thereof being in com- 
munication with said first chamber through the open- 
ing in said inner shell and the second end extending 
to the exterior of said second chamber; 
a tubular insulating means surrounding said conduit 
near the first end thereof; 
a first flange integrally fused to the insulating means 
adjacent said first end of said conduit for coupling 
said insulating means to said inner shell about the 
opening thereof with the first end of said conduit in 
communication with said first chamber; 
an elongated tube concentric with said conduit and sur- 
rounding a portion thereof in said second chamber, 
said tube being spaced from said straight conduit 
except at one end exterior to said second chamber so 
as to define an annular space, around the conduit in 
said second chamber, which sapce is in communica- 
tion with the second chamber; and 
flexible means integrally coupled to said tube and to 
said outer shell for flexibly sealing said tube and the 
conduit concentric therewith in said second chamber, 
whereby a portion of said conduit extending through 
said second chamber is surrounded by said thermal 
insulating means and substantially the rest of the 
exterior surface of said conduit in said second cham- 
ber is surrounded by the annular space which is in 
communication with said second chamber. 
2. The arrangement as recited in claim 1 wherein said 
flexible means comprises a bellows having one end thereof 
integrally connected to said tube near the inner end there- 
of at which the annular space defined thereby is in com- 
munication with said second chamber and an opposite 
end of said bellows is coupled to said outer shell about 
the opening thereof to enclose said second chamber from 
the environment exterior thereto. 
3. The arrangement as recited in claim 2 wherein the 
interior of said bellows is in communication with the en- 
vironment exterior the second chamber and the exterior 
of said bellows is in communication with the environment 
in said second chamber. 
4. A vacuum jacketed chamber adapted to contain a 
cryogenic media or the like at a low temperature substan- 
tially below ambient temperature the combination 
comprising: 
a first wall defining a first inner chamber; 
a second wall surrounding and spaced from said first 
wall and defining with said first wall a second cham- 
ber adapted to be evacuated to provide a barrier to 
the admittance of ambient heat therethrough to said 
first chamber; 
a first elongated hollow tube having first and second 
ends, with said first end extending to said first cham- 
ber through said second chamber; 
a tubular thermal insulator surrounding and concentric 
with said first tube near the first end thereof; 
a first flange fused to the end of said thermal insulator 
near the first end of said first tube; 
means connecting said first flange to said first wall with 
the first end of said first tube therein whereby cryo- 
genic media may be introduced into and removed 
from said first chamber through said first end; 
a second hollow elongated tube concentric with said 
first tube and surrounding a portion of said first tube 
which extends through said second wall into said 
second chamber; 
a first end of said second tube exterior to said second 
chamber being fused to said first tube, whereby the 
tubes define an elongated annular space about said 
3,446,387 
6 
References Cited 
UNITED STATES PATENTS 
5 
first tube which communicates with said second 
chamber near the second end of said second tube; 
and 
fleexible means with fist and second ends the fist end 1,392204 911921 Nichols _ _ _ _ _ _ _ _ _ _ _ _ _  220-14 
being coupled to the second end of said second tube 3,059,804 1011962 'Wissmiller _ _ _ _ _ _ _ _ _ _ _  220-14 
and its second end to said second wall, whereby said 
second wall is flexibly connected to said second tube. 
5. The combination defined in claim 4 wherein said 
flexible means comprises a bellows whereby the interior 
of said bellows is at the environment exterior said second 1o GEORGE E. 
chamber and the exterior of said bellows is at the vacuum 
of said second chamber. 
FOREIGN PATENTS 
180,082 5/1922 Great Britain. 
579,840 811946 Great Britain. 
p,.imcary Em,,,iner. 
JAMES R. GARREW, Assistant Examiner. 


Piping arrangement through a double chamber structure

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