NASA Tech Briefs - Diaphragm Pump With Resonant Piezoelectric Drive

Subscribe to NASA Tech Briefs

Home

Tech Briefs

Mechanics

Diaphragm Pump With Resonant Piezoelectric Drive

Lyndon B. Johnson Space Center, Houston, Texas

Aug 31 2007

Page 2 of 2

The piezoelectric stack would be driven electrically to make it oscillate at the resonance frequency of the spring-andmass structure. This frequency could be made high enough (of the order of 400 Hz) that the masses of all components could be made conveniently small. The resonance would amplify the relatively small motion of the piezoelectric stack (a stroke of the order of 10 μm) to a diaphragm stroke of the order of 0.5 mm. The exact amplification factor would depend on the rate of damping of oscillations; this, in turn, would depend on details of design and operation, including (but not limited to) the desired pressure rise and volumetric flow rate. In order to obtain resonance with large displacement, the damping rate must be low enough that the energy imparted to the pumped fluid on each stroke is much less than the kinetic and potential energy exchanged between the mass and spring during each cycle of oscillation.

Figure 2. This Circuit Would Recover Energy returned by the piezoelectric actuator during each cycleof oscillation, thereby minimizing the power demand of the pump.

To minimize the power demand of the pump, a highly efficient drive circuit would be used to excite the piezoelectric stack. This circuit (see Figure 2) would amount to a special-purpose regenerative, switching power supply that would operate in a power-source mode during the part of an oscillation cycle when the excitation waveform was positive and in a power- recovery mode during the part of the cycle when the excitation waveform was negative. The circuit would include a voltage-boosting dc-to-dc converter that would convert between a supply potential of 24 Vdc and the high voltage needed to drive the piezoelectric stack. Because of the power-recovery feature, the circuit would consume little power. It should be possible to build the circuit as a compact unit, using readily available components.

This work was done by Michael G. Izenson, Robert J. Kline-Schoder, and Martin A. Shimko of Creare, Inc. for Johnson Space Center. For further information, contact the Johnson Commercial Technology Office at (281) 483-3809. MSC-23112.

<< Start < Prev 1 2 Next > End >>

Dedicated to helping you design better products in a digital world... your guide to the latest tools & techniques for digital prototyping, simulation, and analysis of the real-world performance of your ideas.

Visit the Digital Design Center

>> Most Popular

>> Related Items

>> Most Searched

>> Newsletter