Wear resistance of flexible diaphragms in fluid control valves is increased by incorporating a soft rubber washer at the bottom of the piston, a flexible buffer between the diaphragm and the valve seat, and a fluid feedback arrangement. The stress and wear of components at the valve seat are minimized

Mac Glashan, W. F.

English

NASA Technical Reports Server

i Chamber
Flexible Buffer
ollii Valve Seat 
DETAIL "A" (VALVE OPEN) 
Soft Rub 
Upper Diaphragm
Piston
Connecting P1 
Soft Rubber Wa: 
Entrance Port 
Valve 
Flexible 
Biasing S
:k Chamber 
Pressure Plate
Metal 
"A"	 Diaphragm 
Metal
Diaphragm 
Exit Port 
May 1965	 Brief 65-10147 
NASA TECH BRIEF 
-0 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia, 22151. 
Improved Fluid Control Valve Extends Diaphragm Life 
The problem: Increasing the wear resistance of 
flexible diaphragms in fluid control valves. Dia-
phragms used in such valves are subject to excessive 
flexure and early rupture from stresses produced by 
contact with the piston and edges of the valve seat. 
The solution: A valve incorporating a soft rubber 
washer at the bottom of the piston to reduce flexural 
stresses on a thin metal diaphragm; a flexible buffer 
between the diaphragm and edges of the valve seat to 
prevent the edges from cutting into the diaphragm; 
and a fluid feedback arrangement which overcomes
the bias of a spring and allows a small force to close 
the valve when cutoff pressure is reached. 
How it's done: The thin metal diaphragm seals the 
fluid chamber from the upper portion of the valve 
when the valve is either opened or closed. When the 
valve is opened the flexible buffer is away from the 
valve seat. Fluid passing into the entrance port flows 
around the valve seat into the fluid chamber and out 
through the exit port. In the closed condition, the 
piston and soft rubber washer push against the dia-
phragm and flex it downward against the buffer, 
(continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern. 
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
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which in turn pushes against the valve seat to prevent 
the flow of fluid into the fluid chamber and connecting 
exit port. 
The large biasing spring acting against the pressure 
plate and the section of the piston within the plate 
keeps the valve normally opened. When the feedback 
pressure above this plate reaches thecutoff value, the 
force exerted by this pressure on the large upper sur-
face of the plate overcomes the biasing force of the 
spring and moves the plate downward, leaving the 
piston free to move downward and close the valve. 
Since the area of the top of the piston is small com-
pared to the area of the pressure plate, the closure 
force due to the pressure on the top of the piston is 
also small. With these improvements, the bias-spring 
characteristics are less critical and the stress and wear 
of the components at the valve seat are minimized.
Note: A related innovation is described in NASA 
Tech Brief B64-10278 dated November 1964. Inquiries 
may also be directed to: 
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California, 91103 
Reference: B65-10147 
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about ob-
taining rights for its commercial use may be made to 
NASA, Code AGP, Washington, D.C., 20546 
Source: William F. MacGlashan 
(J PL-345) 
Brief 65-10147
	
SCategory No. 05


Improved fluid control valve extends diaphragm life

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