Free Newsletter
Register for our Free Newsletters
Newsletter
Zones
Associations, Services and Universities
LeftNav
Automotive Industry
LeftNav
Design & Manufacturing Services
LeftNav
Education, Training and Professional Services
LeftNav
Electrical Components
LeftNav
Electronic Components
LeftNav
Energy
LeftNav
Fastening and Joining
LeftNav
Laboratory Equipment
LeftNav
Machine Building & Automation
LeftNav
Maintenance, Repair and Overhaul (MRO)
LeftNav
Materials & Processes
LeftNav
Materials Processing and Machine Tools
LeftNav
Mechanical Components
LeftNav
Packaging
LeftNav
View All
Other Carouselweb publications
Carousel Web
Defense File
New Materials
Pro Health Zone
Pro Manufacturing Zone
Pro Security Zone
Web Lec
 
 
News

Parametric excitation: measuring flow using a tiny wobbling tube

University Of Twente : 03 January, 2013  (Special Report)
One milligram per hour: fluid flow can be measured with great precision using a tiny ′wobbling’ tube with a diameter of only 40 micrometres. Thanks to a new technique, the sensor, which makes use of the ′Coriolis effect’, can be made even more compact, e.g. for medical applications.
Parametric excitation: measuring flow using a tiny wobbling tube

Coriolis meters are often enormous instruments mounted in a pipeline to measure liquid flow accurately. Reduced to micrometre dimensions the result is a sensor that can measure extremely slow-moving small quantities of fluids. The fluid is passed through a tiny rectangular tube that is made to wobble. The Coriolis effect then causes the tube to move upwards as well, and this upward displacement is a measure of the amount of fluid flowing through it.

Mechanism of action: the tube is rotated in a wobbling motion (curved arrows). As a result of the Coriolis effect the flowing fluid also experiences an upward force, which is a measure of the flow.No magnets

Until now magnets have been used to bring about the wobbling motion. One of the problems was that the magnets are far bigger than the actual sensor. In an Applied Physics Letters article researcher Harmen Droogendijk has introduced a new method, known as ‘parametric excitation’. Dozens of ‘electric fingers’ attached to the tube fit between identical opposing fingers mounted on supports running parallel to the tube. The extent to which these opposing sets of fingers slide between one another can be used to measure the tube's lateral displacement. But we could also use them to set the tube in motion, thought Droogendijk. He found that there is a limited area of electrical tension where the tube moves up and down much more than at a lower or higher tension, though this has to be tuned very precisely. Droogendijk carried out mathematical modelling, resulting in a new design that no longer needs magnets. More research is needed to find out whether the current lower limit of approximately 1 milligram per hour can be lowered even further.

The research was carried out in the Transducers Science and Technology group led by Prof. Gijs Krijnen, which is part of the University of Twente’s MESA+ Institute for Nanotechnology. It received financial support from the Dutch national nanotechnology program NanoNed. More research is needed to find
out whether the current lower limit of approximately 1 milligram per hour can be lowered even further.

Industrial applications

The Coriolis mass flow sensor is being further developed by Bronkhorst High-Tech in Ruurlo to produce a precision instrument for such things as monitoring medical IV pumps, analysing medicines using liquid
chromatography, and use in microreactors and the manufacture of solar cells.

Attached files
The Coriolis mass flow sensor. The tube is the U-shaped tiny line. In the left lower corner, the electric fingers are visible for measuring the displacement of the tube and activating movement
Mechanism of action: the tube is rotated in a wobbling motion (curved arrows). As a result of the Coriolis effect the flowing fluid also experiences an upward force, which is a measure of the flow.
 

Parametric excitation of a micro Coriolis mass flow sensor. Harmen Droogendijk, Jarno Groenesteijn, Jeroen Haneveld (Micronit Microfluidics), Remco Sanders, Remco Wiegerink, Theo Lammerink, Joost Lötters (Bronkhorst High-Tech) and Gijs Krijnen. Applied Physics Letters.

Bookmark and Share
 
Home I Editor's Blog I News by Zone I News by Date I News by Category I Special Reports I Directory I Events I Advertise I Submit Your News I About Us I Guides
 
   © 2012 ProManufacturingZone.com
Netgains Logo