A Proportionally Controlled Microvalve using a Piezoelectric Unimorph Microactuator

A Proportionally Controlled Microvalve using a Piezoelectric Unimorph Microactuator

Gunda, Arun (TU Delft Mechanical, Maritime and Materials Engineering)

Ghatkesar, Murali (mentor)
Tichem, Marcel (graduation committee)
Goosen, Hans (graduation committee)
Lötters, J.C. (graduation committee)

Delft University of Technology

Mechanical Engineering

2019-08-21

Microvalves are important flow-control devices in many standalone and integrated microfluidic applications. PDMS-based (Polydimethylsiloxane) pneumatic microvalves are the most commonly used type for research purposes, but they require large peripheral connections and cannot be used for controlling gases due to the high gas permeability of PDMS. There are many alternatives found in the literature that use Si-based microvalves, but variants that can throttle even moderate pressures (1 bar) tend to be bulky (cm-range), have a complex fabrication process, or consume high power. This thesis details the development of a low-power, normally-open piezoelectric microvalve to control flows with a maximum driving pressure of 1 bar, but also retain a small effective form-factor of 5mm x 5mm x 1.8mm. A novel combination of rapid-prototyping methods like stereolithography and laser-cutting was used to realize this device. The maximum displacement of the fabricated microactuator was measured to be 8.5 μm at 150V. The fabricated microvalve has a flow-range of 0 - 90 μL/min - water at 1 bar inlet pressure. When fully closed, a leakage of 0.8% open-flow was observed with a power-consumption of 37.5 μW. A flow resolution of 0.2 μL/min was measured at 0.5 bar pressure.

microvalve
piezoelectric
unimorph
3D-printing

http://resolver.tudelft.nl/uuid:652473a6-547e-4a86-8f64-c5f5bf79e986

2020-12-31

Student theses

master thesis

© 2019 Arun Gunda