Open Competition 5 - Electronics and Photonics

Pressure-Balanced Plate Type Microvalve Applied to High-Pressure, High Flow Fluidic Systems

Sponsor: Microstaq (formerly Alumina Micro, LLC)

• Project Performance Period: 7/1/2002 - 9/30/2004
• Total project (est.): $2,539,011.00
• Requested ATP funds: $2,000,000.00

Micro electro-mechanical systems (MEMS) have attracted a great deal of interest because of the potential to replicate in mechanical systems the advantages of microelectronics-versatile devices in tiny packages at relatively low costs. Translating the tiny motions of microscopic elements etched out of silicon into the forces and movements required by real-world applications remains a major challenge. Alumina Micro proposes to meet this challenge with a unique silicon microvalve capable of handling demanding, real-world tasks. Their first target application is a control system for automobile air-conditioning that will require the microvalve to operate accurately, repeatedly, and durably for long periods managing pressures up to 3450 kilopascal (roughly 34 times atmospheric pressure) and flow rates up to 50 standard liters per minute. The novel all-silicon microvalve design incorporates several special features, including a pressure-balance system to overcome typical pressure differential related mechanical difficulties, and a multi-stage valve arrangement that should enable it to handle much higher flow rates than any present-day microvalves. Additionally, the innovative design assures reliable operation within a large temperature range. The finished device, roughly about the size of a penny, would take the place of an electric solenoid many times larger. High-risk portions of the project include: developing cost-effective manufacturing processes to form the silicon elements of the valve and to bond multiple layers of silicon together strongly enough to resist the high operating pressures without leaks, achieving the planned flow rate and volume (which greatly exceeds the capabilities of any present-day microvalve), maintaining the bonds over long periods of use, and developing the necessary interface to mate the microfluidic ports to a macrofluidic channel. Potential economic benefits of the technology stem not only from the compact size of the device, but also from increased efficiencies due to the higher resolution control the microvalve will provide over present-day solutions. A MEMS-based control system built into a typical variable displacement compressor in an auto a/c system would consume an estimated 50 percent less power and require 75 percent less space, while offering more precise control. One manufacturer calculates that the improvement in control would translate to savings of about 1/2 mile per gallon in fuel efficiency. To give an idea of scale, over the entire U.S. auto fleet that would come to about 33 million barrels of fuel per year and reduced vehicle emissions of about 9.8 million metric tons per year. There are other potential applications for the MEMS microvalve in control systems for the medical and chemical industries. Rensselaer Polytechnic Institute (Troy, N.Y.) will contribute to the project in creating flow models. Alumina Micro, a small company, has been unable to raise sufficient research capital for this project because of the several technical uncertainties. ATP support will accelerate the development of the technology by an estimated two years, potentially allowing U.S. automakers to beat foreign competitors to market.

For project information:

Jeff Chancey, (360) 734-8220
jchancey@aluminamicro.com

ATP Project Manager

Michael Schen, (301) 975-6741
michael.schen@nist.gov