Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized

Erwin, L. R.

Schwartz, H. W.

Teitelbaum, B. R.

English

NASA Technical Reports Server

Seat 
Ball
al 
:tion 
May 1972	 B72-10204 
NASA TECH BRIEF 
Ames Research Center	 G 
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 program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
A Piezoelectrically Actuated Ball Valve 
The problem: 
To develop a small, lightweight valve that is not 
operated by bulky coils or structures carrying mag-
netic flux.
when a voltage is applied across them, the strip 
curves much as a bimetal strip curves when heated. 
The ceramic layers are bonded together so that they 
are poled in opposite directions across the thickness, 
Pi,rItfri,	 SId 
Port	 Spring	 Port	 Spring 
The solution: 
A valve which utilizes the piezoelectric effect. 
How it's done: 
A piezoelectric bimorph strip closes and opens the 
valve. The strip is composed of two layers of poled 
piezoelectric ceramic material. The two outer sur-
faces are covered with a conductive plating and,
and a thin metal shim may be interposed between 
the two layers to enhance conductivity. In the device 
shown in the figure, a voltage of the proper polarity 
applied to the electrical connection will make the 
left-hand end of the strip move downward, and the 
opposite polarity will make it move upward. When 
the voltage is removed, the strip returns to its initial 
position and the ball rests against its seat. Since the 
(continued overleaf) 
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https://ntrs.nasa.gov/search.jsp?R=19720000204 2020-03-17T03:32:15+00:00Z
piezoelectric strip performs like a capacitor, there is 
an initial inrush of current when the valve is ener-
gized, and then only a small leakage current flows 
as the valve remains energized. 
A typical value of maximum voltage gradient for 
piezoceramic material is 0.59 volts per pm (15 volts 
per mil). Thus, if the total thickness of the strip is 
762 p.m (30 mils), 450 volts will be required to obtain 
the maximum deflection. Although this voltage ap-
pears high compared to the voltages required by 
conventional magnetically actuated valves, the energy 
consumed by the valve in watt-seconds per actuation 
will be very much lower than conventional valves. 
However, since high voltages are required, the piezo-
electric valve can only be used in gases and non-
conductive liquids unless it is fully insulated. 
In low flow rate, low pressure applications, the 
valve is advantageous because of its small size, light 
weight, and low electrical power consumption. It is
also capable of sharp, repetitive action because its 
inductance is negligible. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10204 
Patent status: 
No patent action is contemplated by NASA. 
Source: Louis R. Erwin, Harlow W. Schwartz, and

Bernard B. Teitelbaum of

Bendix Aerospace Systems Division

under contract to

Ames Research Center 
(ARC-10338) 
B72-10204	 Category 06


A piezoelectrically actuated ball valve

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