Photometric analyzer measures NVR /nonvolatile residue/ in trichloroethylene and other organic solvents. The analyzer converts the liquid solvent to aerosol and passes it between an optically focused light beam and a photodetector that is connected to standard amplifying and readout equipment

Salkowski, M. J.

Werle, D. K.

English

NASA Technical Reports Server

July 1966
	 Brief 66-10320 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Solvent Residue Content Measured by Light Scattering Technique 
Aerosol Sheath Air
$ Air Supply 
Filter
Collimator 
Regu-
lator
Phototube 
r 01	 1	 iorat ed Disk 
N2 Supply Exhaust 
Light 
Source
Vacuum Pump
Micro-
Micro 
Ammeter 
The problem: 
In cleaning large vessels, volatile organic solvents 
will leave traces of nonvolatile residue (NVR) that 
can cause system problems if above a certain con-
centration. Measurement of NVR in trichloroethylene, 
a typical solvent for cleaning large vessels, has pre-
viously been by the tedious and time consuming 
gravimetric method.
The solution: 
A system that converts the NVR-bearing solvent 
to a fine aerosol and passes the aerosol between an 
optically focused light beam and a photodetector that 
is connected to standard amplifying and readout 
equipment. 
How it's done: 
The solvent containing the NVR is filtered to re-
(continued overleaf) 
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. 
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move all insoluble particles that would interfere with 
the analysis. The filtered solvent is then nebulized to 
a fine spray that is warmed slightly to evaporate most 
of the volatile solvent and leave a residual aerosol of 
the NVR. This residual aerosol is passed through a 
collimator that provides a clean, particulate-free air 
sheath around the aerosol filament as the filament 
passes through a light beam that is focused on a light-
scattering photometer. The photometer produces an 
electrical signal that is directly related to the concen-
tration of NVR in the solvent. 
Notes: 
1. A calibration curve for this nebulizer—light scatter-
ing photometer system was obtained by nebulizing 
standard volatile solutions containing known 
amounts of NVR as determined by the gravimetric 
method.
2. This system provides numerical cleanliness data 
on fluid tanking and distribution systems. 
3. Inquiries concerning this invention may be di-
rected to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B66-10320 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: Donald K. Werle and Martin J. Salkowski

of Illinois Institute of Technology Research Institute

under contract to

Marshall Space Flight Center

(M-FS-850) 
Brief 66-10320	 Category 01


Solvent residue content measured by light scattering technique

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