System controls two or more pneumatically operated metering valves from common pneumatic source without interaction between valve controls. Unit affords independent metering of liquid from single source to two concurrent applications. Calibration and testing demonstrate complete absence of interaction between valves and corresponding flow rates

Hawkins, D. E.

English

NASA Technical Reports Server

Legend.	 Pneumatic 
itor	 Throttle Valve 
ure, 
)Sig rk  3-Way Solenoid Valve 
Thermocouple 
Flowmeter 
Primary e 
Flow
®
Pressure 
Transducer 
0 Pressure Gage 
ft 1 i I 1 1 O Filter 
ndary System Flow
5' 
Manual 
Pressur
 
Con 
140
November 1970	 Brief 70-10244 
NASA TECH BRIEF
	
/ 
NASA Tech Briefs announce new 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 progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Precision Control System for Engine Fuel 
Throttle Valve Control System Schematic
	
Control Air 
This control system represents a potentially useful 
new method of controlling two or more pneumatically 
operated metering valves from a common pneumatic 
source without interaction between the valve controls. 
The information should interest personnel engaged 
in the design and maintenance of pneumatic, hydrau- 
lic, and electrical control systems. 
The innovation affords independent metering of 
liquid from a single source to two concurrent appli- 
cations. Downstream of the system main valve, the
flow is divided. Each line is provided with a variable 
position control valve which is pneumatically con- 
trolled to provide independent regulation of the liquid 
flow rate. Positioning of the valve plugs is obtained 
through the use of a constant loading pressure and 
a variable control pressure, as shown in the figure. 
The valve position is indicated by a linear slide trans- 
ducer. Thus, after system calibration, the valve po- 
sition can be controlled predictably, and any reason- 
able change in either flow can be effected. Calibration 
(continued overleaf) 
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=19700000235 2020-03-17T00:15:07+00:00Z
and testing demonstrated a virtually complete ab-
sence of interaction between the two valves and the 
corresponding flow rates. 
In one proposed application, two separate flow rates 
of the fuel diborane (13 2 1-1 6) had to be controlled in-
dependently with accuracy, repeatability, and con-
venience, from a single tank and main line. The pur-
pose of the flow control system was to provide ac-
curate metering of both the main engine fuel injector 
(primary) flow and the separately manifolded film 
coolant (secondary) flow from the same tank of di-
borane. The throttle valves performed the dual role 
of shutoff valves and calibrated, variable position 
orifices. 
Contoured valve plugs had to be specially designed 
to provide accurate throttle control over the specified 
ranges of flow. Extensive calibration and over 50 tests 
proved the effectiveness of the system. Time for stable 
flow appeared dependent only on the line and mani-
fold volume downstream of the valves and not on 
damping of valve position fluctuations. Stable flows 
were obtained within 0.5 sec of throttle valve oper-
ation from full closed to test position. 
To effect meaningful calibration and testing, a 
closed loop, 1-butene system was temporarily plumbed 
into the facility just upstream of the dual line sections, 
for the purpose of calibrating the throttle valves. The 
fuel simulant, 1-butene, was used because of its low 
viscosity and density and its compatibility with di-
borane. 
Calibrations were made to determine throttle valve 
position versus flow rate and pressure drop for the 
test conditions to be encountered. Each valve was 
calibrated separately to determine if suitable ranges
of flow could be obtained with a given common tank 
pressure. Then both sides were operated together to 
determine the effect of varying one valve position on 
the flow through the other valve. 
Flow rate was plotted against throttle valve po-
sition. In the tests, the objective was to determine the 
flow rate interdependence of the two valves, with a 
constant upstream (tank) pressure, to determine how 
much effect a variation in one valve had on the flow 
through the other. Consequently, a sequence of seven 
flows was made with the primary throttle valve po-
sition fixed and the secondary valve position varied 
systematically. All of the primary flow rates, corre-
sponding to the seven tests, fell within the range of the 
initial data point. In a similar manner, a sequence of 
tests was made holding the secondary throttle valve 
fixed in position and varying the primary valve. The 
results again showed that a constant flow rate was 
maintained through the fixed valve. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: B70-10244 
Patent status: 
No patent action is contemplated by NASA. 
Source: D. E. Hawkins of 
North American Rockwell Corporation 
under contract to 
NASA Pasadena Office 
(NPO-12017) 
Brief 70-10244	 Category 07


Precision control system for engine fuel

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