A Silicon Microvalve for the Proportional Control of Fluids

Kirt R. Williams, Nadim I. Maluf, E. Nelson Fuller, Richard  J. Barron, 
Dominik P. Jaeggi, and Bert P. van Drieënhuizen

Digest of the 10th International Conference on 
Solid-State Sensors and Actutors (Transducers '99),
Sendai, Japan, June 1999, pp. 1804-1807.


ABSTRACT

We present a new type of micromachined plate valve with pressure-force 
balancing for operation at elevated pressures. 
The valve can proportionally control the flow of both gases and liquids.
Due to its structure, it can be configured as normally open or normally closed. 
We have fabricated and tested several versions of the valve, 
including lower-pressure and higher-pressure valves. 
The lower-pressure version controls nitrogen up to 1 bar 
without hysteresis or leakage, 
and has operated up to 10 bar with a flow rate of  6.7 l/min. 
The other version controls liquid flow up to 14 bar. 
The valves are driven by a thermal actuator with a 
mechanical linkage capable of over 100 um of motion. 
The chip is almost entirely silicon, 
eliminating actuation due to mismatch of thermal expansion rates.