Joint absorbs all significant torque, is as rugged as heavy metallic pipe, and has thermal insulation comparable to length of flexible pipe. Design is adaptable to any pipes transporting gases or liquids, including those which are noxious or corrosive

Mursinna, R. C.

English

NASA Technical Reports Server

February 1971	 Brief 71-10018 
NASA TECH BRIEF 
KenA'ledv Space Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a aubscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the. Tech Brief program may 
be directed to the Technology, Utilization Office, NASA, Code KT, Washington, D.. 20546. 
Vacuum-Jacketed Rotary Joints for Pipelines 
A rotary joint mechanism can be used on vacuum-
jacketed pipelines carrying liquified gases at ultralow 
temperatures. The design can easily be adapted to any 
pipes (particularly, insulated lines) transporting gases 
or liquids, including those that are noxious or cor-
rosive.
Insulation 
Insulation
Cones 
Ambient Pressure 
Seal 
Roller Bearings 
Environmental 
Cryogenic Seal	 Pressure Seal 
A jacketed pipeline transporting cryogenic liquified 
gas may require rotation points at various interfaces 
in the line— for instance, swinging arms at delivery 
points. Such rotation has been provided by flexible 
lengths of line' which have thin walls easily damaged 
by impact or corrosion. In addition, these lines trans-
mit the torsional loads applied to them. One ob-
jective in designing the new joint was to permit 
rotary motion while restricting heat loss to no more 
than that from a standard coupling. 
The new joint (see fig.) absorbs all significant
torque and is as rugged as heavy metallic pipe. 
In addition, its thermal insulation compares with 
that of a length of flexible pipe. The calculated 
heat leak for a 20.32 cm (8 in.) rotary joint was 9240 
watts (315 Btu/hr), while tests with liquid nitrogen 
showed a leak rate of 6717 watts (229 Btu/hr). No 
liquid leak was detectable when the joint was stat-
ically pressurized to 206.7 kN/m 2
 (30 psi) with 
liquid nitrogen. When the joint was rotated at 
24.15 rad/sec (3.2 rpm) with a side load of 3400 
joules (2500 ft-lb), the torque required was 272 joules 
(200 ft-lb) and the leakage was less than 137 cm3/sec 
(5 in 3 /min) (standard). Joints measuring 15.24 cm(6in) 
were also built and tested. 
The rotary joint includes: a combination of a sliding 
cryogenic lip seal, a sliding ambient-pressure lip seal, 
an environmental lip seal, an insulation structure, 
conical-block insulation, and a roller-bearing arrange-
ment, all of which permit low-torque rotation and 
restrict heat leak to that of a typical bayonet joint; 
incorporation of overlapping conical supports and 
thermally isolating members which reduce face-to-
face dimensions; long-heat-path cones which greatly 
reduce heat input to the fluid; and bearings which 
remain at ambient temperature while cryogenic fluids 
are handled. With cryogenic fluid being transferred, 
the joint can be either stationary or rotating, and the 
primary lip seal will remain at ambient temperature. 
Another interesting feature is that heat leakage 
to the fluid is reduced considerably by enclosing at 
least 90% of the joint in a vacuum to eliminate 
conduction and convection. Using a porous insulating 
block greatly reduces heat transfer between the fluid 
and the ambient-temperature jacket; the block pre-
vents gas permeation and has a conductivity of less 
than 1.44 watts/m (0.15 Btu/hr-ft).
(continued overleaf)' 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned.rights.
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Note:	 Patent status: 
The following documentation may be obtained 	 No patent action is contemplated by NASA. 
from:
National Technical Information Service 	
Source: R. C. Mursinna of 
Springfield, Virginia 22151	
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Kennedy Space Center 
(KSC-105 19) 
Reference:	 S 
NASA-CR- 107244 (N70-31965), Vacuum 	 S 
Jacketed, Umbilical Lines Technology Ad-	 S	 S	 S 
\'ancement Study	 S	 S	 S 
Brief 71-10018
	 Category 07


Vacuum-jacketed rotary joints for pipelines

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