Fixture facilitates inspection testing of circumferential pipe welds for vacuum tightness, using helium gas as a leakage tracer in conjunction with a mass spectrometer. It consists of a split rubber torus and a mating clamping ring with a vacuum hose fitting

Roney, J. A.

English

NASA Technical Reports Server

June 1967	 Brief 67-10178 
NASA TECH BRIEF C' 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Fixture Facilitates Helium Leak Testing of Pipe Welds 
To Mass Spectrometer 
Helium (.ias 
The problem: 
To devise a fixture that will facilitate inspection 
testing of circumferential pipe welds for vacuum tight-
ness, using helium gas as a leakage tracer in conjunc-
tion with a mass spectrometer. The pipes to be tested 
were too large for a vacuum chamber, and the use of 
a plastic bag taped around the welded joint for col-
lection of the tracer gas did not provide sufficient 
measurement accuracy of the leakage rate.
The solution: 
A fixture consisting of a split rubber torus and a 
mating clamping ring with a vacuum hose fitting. 
How it's done: 
The rubber torus is placed over the weld to be 
tested and the clamping ring is tightened around the 
torus to ensure a vacuum tight seal. A vacuum line 
is then connected between the vacuum hose fitting 
and the mass spectrometer. Any helium that leaks 
(conunuod oveilcal) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000178 2020-03-11T20:51:33+00:00Z
	through the weld accumulates in the annular space
	 2.. Inquiries concerning this innovation may be di-
	
within the rubber torus and is conducted to the mass
	 rected to: 
	
spectrometer. As the pressure of the helium is con-
	 Technology Utilization Officer 
	
siderably below atmospheric, helium leakage to the
	 Marshall Space Flight Center 
atmosphere is negligible.
	 Huntsville, Alabama 35812 
Reference: B67-10178 
Notes:	 Patent status: 
	
1. This fixture enables accurate and rapid helium leak
	
No patent action is contemplated by NASA. 
	
testing of welded pipe joints, since it can be con-
	 Source: James A. Roney 
	
nected (and disconnected) within several seconds
	 of Hayes International Corporation 
	
and requires only a few more seconds for estab-
	 under contract to 
	
lishment of the equilibrium gas pressure in the
	 .	 Marshall Space Flight Center 
	
known annular volume of the rubber torus around
	 and Robert G. Jones 
the weld bead.	 (M-FS-2167) 
Brief 67-10178	 Category 05


Fixture facilitates helium leak testing of pipe welds

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