Filtered samples of molten metals are obtained by filtering through a plug of porous material fitted in the end of a sample tube, and unfiltered samples are obtained by using a capillary-tube extension rod with a perforated bucket. With these methods there are no sampling errors or loss of liquid

Burris, L., Jr.

Pierce, R. D.

Tobias, K. R.

Winsch, I. O.

English

NASA Technical Reports Server

March 1967
	
Brief 67-10034 
AEC-NASA TECH BRIEF 
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Two Techniques Enable Sampling of Filtered and Unfiltered Molten Metals 
Bucket 
Simple Bucket Unit	 Unit Attached to Capillary Tube 
pl-
Capillary 
Steel Rod 
Steel Rod	
Tantalum 
Holesj 
Tantalum 
SAMPLERS FOR OBTAINING UNFILTERED 
SAMPLES OF METAL SOLUTIONS 
The problem: 
To obtain samples of unsaturated liquid-metal 
solutions and two-phase metal—metal and metal—salt 
solutions. In two-phase systems, a provision must be 
made for sampling the lower phase. 
If a filtered sample is desired, the solute element is 
filtered off the solid phases in suspension. The sample 
tube and the filter material must be inert to the sample 
solution and structurally strong. To avoid sampling 
errors, drainage of any sample liquid out of the sample 
tube must be prevented. Drainage reduces the concen-
tration of the liquid phase and increases the weight per-
cent of the solid phase (by forming crystals on the solid 
phase). After sampling, the entire sample must be 
removed for analysis because the solute in the sample 
may separate during cooling. 
For an unfiltered sample, the solute element is ob-
tained by drawing off part of the supernatant liquid,
Tantalum Tubes with 
Tantalum Frits
Ill	 Capillary 
Steel Rod	
Steel Tube 
Wall Tantalum 
Porous Tantalum Plug 
SAMPLERS FOR OBTAINING FILTERED
SAMPLES OF METAL SOLUTIONS 
and there must be no loss of supernatant liquid or 
mother liquor. 
The solution: 
Filtered samples are obtained by filtering the solu-
tions under the action of a pressure differential 
through a plug of a porous filter material fitted into 
the end of a sample tube. Unfiltered samples are ob-
tained by using a perforated or open bucket with an 
attached steel extension rod; however, a capillary-tube 
extension rod used with a perforated bucket is a more 
reliable setup. 
How it's done: 
For obtaining filtered samples, a fritted filter ma-
terial is selected that is inert to the sample solution. 
The fritted plug is fitted into an inert and structurally 
strong sample tube and is held in place by roller-seal-
ing or force-fitting. The end of the tube not containing 
(continued overleaf) 
• 
This document was prepared under the sponsorship of the Atomic 	 liability resulting from the use of the information contained in this 
Energy Commission and/or the National Aeronautics and Space document, or warrants that the use of any information, apparatus, 
Administration. Neither the United States Government nor any per- 	 method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000034 2020-03-11T20:18:17+00:00Z
the plug is attached to an extension rod. During 
sampling, the rod extends above the melt. 
The sample solution is forced into the sample tube 
-- by external pressure on the solution surface or by 
application of a vacuum through a capillary tube 
inserted into the sample tube. The lower phase of a 
two-phase solution is sampled by blowing inert gas 
through the capillary tube and the frit while the tube 
is lowered through the upper phase. The pressure dif-
ferential depends on solution properties, porosity of 
the frit, and wetting of the frit by the solution. To 
prevent sample loss: (I) drainage of the sample liquid 
out of the sample tube is prevented by the frit and (2) 
the pressure outside the tube or the vacuum within the 
tube is maintained until the sample solidifies. The 
entire sample is removed either by peeling the tube 
away from the sample or by dissolving the sample out 
of the tube. 
For obtaining unfiltered samples, a perforated or 
open bucket is attached to the steel rod and lowered 
into the solution. Bucket samplers ensure against loss 
of supernatant liquid or of motor liquor. A more 
reliable assembly is a capillary tube steel rod attached 
to a bucket containing holes. With this setup, a sample 
can be drawn through the holes regardless of whether 
the sample liquid wets the sampler. The lower phase 
of a two-phase system is sampled by blowing inert gas 
through the capillary while the bucket is lowered 
through the upper phase. 
Notes: 
1. Obtaining filtered samples usuaIly'tak 2 minutes 
(including preliminary heat-up of the sample tube 
to prevent solidification of the sample on it) with a 
pressure differential of 10 to 20 psia. 
2. Obtaining unfiltered samples takes about 5 seconds 
(excluding a I-minute heat-up).
3. Because the solutions used were zinc-rich, only 
graphite, tantalum, tungsten and certain of its 
alloys, and various ceramic materials could be used 
in the sampling system. A tantalum frit and a tan-
talum sample tube were chosen because a graphite 
frit in Vycor tubing caused interactions of the 
sample with the filter, occasional fracture of the 
plug, and occasional breakage of the tube. Tanta-
lum frits are available in coarse, medium, and fine 
porosities. 
4. Stainless steel filters in thicknesses of 1/16 to 1/4 
inch are available in a number of porosities. These 
filters are used for sampling alkali, alkaline earth, 
and cadmium metal solutions. Fritted filters of 
nickel, Monet, platinum, gold, silver, and tungsten 
are also available. 
5. Additional details are contained in: "Sampling of 
Liquid Metal," by 1. 0. Winsch, et al, ANL-7088, 
September 1965. This report is available from the 
Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151; price 
$3.00 (microfiche copies, $.65). 
6. Inquiries concerning this innovation may be di-
rected to: ,	 - 
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B67-10034 
Source: 1. 0. Winsch, K. R. Tobias, 
R. D. Pierce, and L. Burns, Jr. 
Chemical Engineering Division 
(ARG-150) 
Patent status 
Inquiries about obtaining rights for commercial 
use of this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commision 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Brief 67-10034	 Category 03


Two techniques enable sampling of filtered and unfiltered molten metals

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server