Positive displacement cylinder accurately measures volumetric flow rates of corrosive liquids. The cylinder is compatible with corrosive liquids and handles flow rates from zero to 75 gpm at pressures to 900 psig with an accuracy of 0.25 per cent

Mariman, R. A.

Vendl, C. J.

English

NASA Technical Reports Server

December 1966	 Brief 66-1O59 
NASA TECH BRIEF 
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. 
Positive Displacement Cylinder Measures Corrosive Liquid Volume 
The problem: 
To accurately measure volumetric flow rates of 
corrosive liquids. Such measurement has, in the past, 
been accomplished by a turbine flowmeter that can-
not sense low flow rates and can only achieve a 0.5°c 
accuracy. 
The solution: 
A positive displacement. cylinder that is compati-
ble with corrosive liquids and that handles flow rates
from zero to 75 gpm at pressures to 900 psig with an 
accuracy of 0.25%. 
How it's done: 
A free floating piston within a cylinder is moved 
by liquid flowing through the device. The piston is 
attached to a rack gear that drives a pinion gear in 
response to the piston's motion. A sprocket, that is 
part of the gear train, rotates beneath a sensing 
device that is actuated by a proximity switch in con-
tact with the sprocket teeth. Each sprocket tooth trips 
(continued overleaf) 
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Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
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https://ntrs.nasa.gov/search.jsp?R=19660000587 2020-03-11T17:45:29+00:00Z
the switch as it passes and produces a pulse in the 
sensing device (400 pulses equal one gallon of liquid 
acting.upon the piston). These pulses are totalized 
continuously and transmitted to a digital recorder. 
As the free piston reaches an end of the cylinder, a 
micoswitch actuates a valve arrangement that re-
verses the direction of liquid flow within the 
cylinder to move the piston and attached rack gear 
in the opposite direction to continue the sprocket 
tooth totalization count indefinitely. 
Notes: 
I. This device could be used for accurate batch mix-
ing of a variety of liquids (other than cryogenic) 
that impose severe environmental compatibility 
problems in their handling.
2. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Manned Spacecraft Center 
Houston, Texas 77058 
Reference: B66-10589 
Patent status: 
No patent action is contemplated by NASA. 
Source: Charles J. Vendl and R. A. Mariman 
of North American Aviation, Inc. 
under contract to 
Manned Spacecraft Center 
(MSC-1038) 
Brief 66-10589	 Category 05


Positive displacement cylinder measures corrosive liquid volume

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