Sampling process was developed which uses commercially available high pressure filters and provides measurements in fraction of time required by older methods. Measurements show no significant difference in results between low pressure and high pressure samples. Filter method is slightly more accurate than scrubber technique

Fickey, E. W.

Peterson, M. H.

English

NASA Technical Reports Server

ve 
Flow Meter 
Regulator 
Box Assy 
Regulator 11 
September 1972	 B72-10540 
NASA TECH BRIEF 
John F Kennedy Space Center 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription 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.C. 20546. 
Improved Sampling of Compressed Gases for
Condensable Hydrocarbon Content 
System Block Valve 
c1h0se .	
Detail "A' 
Filter Holder 
F Iowmeter 
The problem: 
The high-purity gases used in the Apollo program 
require periodic measurements for condensable hydro-
carbon contaminants. Previously, these measurements 
were conducted with a series of absorption chambers 
filled with carbon tetrachloride. This process was time 
consuming and required venting of the toxic carbon 
tetrachloride. 
The solution: 
An improved sampling process was developed which
uses commercially available high-pressure filters and 
provides measurements in a fraction of the time required 
by the previous method. 
How it's done: 
The equipment for the new sampling method is shown 
in the figure. Gas is received from the source at specified 
flow rates. It continues through a high pressure filter 
holder which is loaded with three 0.45- pm filters and 
flow, through the pressure regulator and out through 
s 
(continued ovërleaf) 
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.
https://ntrs.nasa.gov/search.jsp?R=19720000539 2020-03-17T03:35:06+00:00Z
the flow meter. When a sufficient amount (595 standard 
liters or 21 standard cubic feet) of gas is sampled, the 
filters are removed and analyzed. 
For comparison, the new technique was tested in 
parallel with the carbon tetrachloride scrubber method. 
Nitrogen and helium gases were tested at 20.7 x 104 to 
41.4 x iO N/rn 2 (30.60 phi) pressures at variable flow 
rates of 4 to 7 standard 1/mm. High pressure samples 
(41.4 x 106 N/m 2 ) were tested at full flow rates of 
141.6 standard 1/mm. 
Measurements show that there is no significant differ-
ence in results between the low-pressure and high-
pressure samples. However, in comparison of the two 
techniques, low-pressure nitrogen samples showed an 
average oil content of 0.08 ppm with filters and 0.03 
ppm with the scrubber method. Similar measurements 
on helium showed an average oil content of 1.27 ppm 
for filters and I .08 ppm for the scrubber. 
As evidenced by the results, the filter method is 
slightly more accurate than the scrubber technique. In
addition, it is faster, safer, and is less subject to con-
tamination. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: TSP72-10540 
Patent status: 
NASA has decided not to apply for a patent. 
Source: M. H. Peterson and E. W. Fickey of 
Bendix Corp.
under contract to
John F. Kennedy Space Center 
(KSC-10304)
17, 
B72-10540	 Category 06


Improved sampling of compressed gases for condensable hydrocarbon content

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