Microvalve for Fuel Cells and Miniature Gas Chromatographic System

Abstract

Microvalves are important for fluid control in a variety of applications, ranging from miniaturized chemical analysis systems, to precision manufacturing and miniature fuel cells. MEMS technology provides the opportunity to miniaturize valves that work with smaller sample volume, operate rapidly with low power and can potentially be integrated with other components on a single chip. A review of actuators for microvalves is provided, including electrostatic, magnetic, piezoelectric, thermal, shape memory alloy and hydrogel. The design and simulation of a magnetic latching microvalve is provided as a case study. The fabrication by surface micromachining with low temperature, potentially CMOS compatible processing is given.

A radio frequency controlled microvalve for biomedical applications

“…Various different actuation schemes are widely used for microvalves and micropumps [1,3,7,[8][9][10]. Different actuation schemes are discussed to identify which actuation mechanism is best suited for the application domain in concern.…”

“…Analysis of different actuation mechanisms for microvalve designs can be found in the literature [1,7,10]. Namely they are piezoelectric, electrostatic, magnetic, pneumatic and thermal actuators.…”

“…Each dimension of the microvalve structure is designed to be limit to a maximum of 10 mm to maintain the miniaturized size of the device. Based on different microvalve structures that have been realised in the literature [1,7,9,10,25], piezoelectric actuators are known for high force operation for a moderate input voltage as discussed in section 3.2. The longitudinal shape and the possibility to isolate the piezoelectric actuator from the fluid flow hence reduce environmental effects on the microvalve structure.…”

“…The manipulation of the fluid flow at nano-litre scale is a fundamental function that has a wide range of applications such as parallel mixing of photo-lithographically defined nanolitre volumes, flow control in pneumatically driven microfluidic systems, lab-on-chip applications, precision manufacturing, drug delivery and miniaturisation of chemical and bioanalysis systems. It is proven that microvalves are essential components of these miniaturised fluidic systems [1].…”

Out-of-Plane Knife-Gate Microvalves for Controlling Large Gas Flows

“…The greatest advantage of microvalves, however, lies in the integration of the actuation mechanism with the other microvalve components, which enhances miniaturization and packaging. A representative overview of the vast amount of work established in this field can be found in [1]. However, gas microvalves are not used yet as standard components in industry because primarily of the cost-per-performance ratio of today's microvalves.…”