Development of a gas microvalve based on fine and micromachining

The work presented in this thesis is generated in the frame of the project “Micro and Miniaturized Flow Controller for Gas Chromatography�? financially supported by the Dutch Technology Foundation (STW). The aim of the project is to develop a miniature instrument for the control of gas flow known as flow controller. An important application of the flow controller is gas chromatography. Gas chromatography is a method for separating substances in a mixture and measuring the relative quantities of substances. It is a useful technique for substances that do not decompose at high temperatures and when a very small quantity of sample (micrograms) is available. Since there is a strong trend to miniaturize these systems as small systems use small amounts of materials and smaller samples for analysis, small flow controllers are demanded. Flow controllers are comprised of controllable valves, flow sensors and control electronics. The research subject in this project is directed mainly to miniature valve, which currently forms the bottleneck in the development of the miniature flow controller. In this thesis a new design of a valve is proposed, which has the attractive feature that no power is required to keep the valve at a freely chosen position. To achieve the aforesaid objective to realize a controllable valve with no power consumption to keep the valve at a freely chosen position, a combination of micromachining and conventional fine machining is explored.