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A Latchable Valve for High-Pressure Microfluidics
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
MultusMEMS.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
2010 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 19, no 2, 396-401 p.Article in journal (Refereed) Published
Abstract [en]

In this paper, the strongest yet latchable valve in subcubic-centimeter size for microfluidic applications is presented. The device has an integrated actuator cavity consisting of three segments filled with paraffin, each operated by a separate heater. At one of the segments, a membrane valve head is deflected by the expansion of the resistively melted paraffin to close against its valve seat. Different heating sequences provide a latched closed or opened valve. The maximum pressure before any leakage occurred was 2.5 MPa. The leak pressure is found to be progressively dependent on the clamping pressure applied. The valve has an opening and closing time of 7 and 1 s, respectively. At an applied pressure of 0.3 MPa, the closed valve needs to be reactivated every 100 min to remain leakage free, leading to an average power consumption of 4.5 mW.

Place, publisher, year, edition, pages
2010. Vol. 19, no 2, 396-401 p.
Keyword [en]
Fluid flow control, microactuators, steel, valves
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
URN: urn:nbn:se:uu:diva-126963DOI: 10.1109/JMEMS.2010.2041749ISI: 000276257700019OAI: oai:DiVA.org:uu-126963DiVA: diva2:328110
Available from: 2010-07-01 Created: 2010-07-01 Last updated: 2017-12-12Bibliographically approved
In thesis
1. High-Pressure Microfluidics
Open this publication in new window or tab >>High-Pressure Microfluidics
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis, some fundamentals and possible applications of high-pressure microfluidics have been explored. Furthermore, handling fluids at high pressures has been addressed, specifically by creating and characterizing strong microvalves and pumps.

A variety of microstructuring techniques was used to realize these microfluidic devices, e.g., etching, lithography, and bonding. To be able to handle high pressures, the valves and pumps need to be strong. This necessitates a strong actuator material. In this thesis, the material of choice is paraffin wax.

A new way of latching paraffin-actuated microvalves into either closed or open position has been developed, using the low thermal conductivity of paraffin to create large thermal gradients within a microactuator. This allows for long open and closed times without power consumption.

In addition, three types of paraffin-actuated pumps are presented: A peristaltic high-pressure pump with integrated temperature control, a microdispensing pump with high repeatability, and a pump system with two pumps working with an offset to reduce flow irregularities. Furthermore, the fundamental behavior of paraffin as a microactuator material has been explored by finite element modeling.

One possibility that arises with high-pressure microfluidics, is the utilization of supercritical fluids for different applications. The unique combination of material properties found in supercritical fluids yields them interesting applications in, e.g., extraction and cleaning. In an attempt to understand the microfluidic behavior of supercritical carbon dioxide, the two-phase flow, with liquid water as the second phase, in a microchannel has been studied and mapped with respect to both flow regime and droplet behavior at a bi-furcating outlet.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 53 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1085
Keyword
phase change, actuator, valve, pump, supercritical fluid
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Microsystems Technology
Identifiers
urn:nbn:se:uu:diva-208915 (URN)978-91-554-8773-7 (ISBN)
Public defence
2013-11-29, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, 751 21, Uppsala, 09:30 (English)
Opponent
Supervisors
Funder
Swedish Research Council
Available from: 2013-11-07 Created: 2013-10-10 Last updated: 2014-01-23

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Ogden, SamBodén, RogerHjort, Klas

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