Micro-flow metering and viscosity measurement of low viscosity Newtonian fluids using a fibreoptical spatial filter technique

Petrak, D.; Rauh, Hagen

doi:10.1016/j.flowmeasinst.2008.12.005

Cited by 9 publications

(2 citation statements)

References 6 publications

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“…The most common are thermal flow sensors (hot-film method, calorimetric method or time-of-flight principle) [3][4][5] and pressure sensors (resonant or differential) [6][7][8]. Other measurement methods use the electrical admittance of a microfluidic channel [9][10][11] or monitor the optical image of a moving object through a capillary (spatial filtering velocimetry) [12].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a cantilever-based microfluidic flow meter with nL min⁻¹resolution

Noeth

Keller

Boisen

2010

J. Micromech. Microeng.

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A microfluidic flow meter based on cantilever deflection is developed, showing a resolution down to 3 nL min−1 for flows in the microliter range. The cantilevers are fabricated in SU-8 and have integrated holes with dimensions from 5 × 5 to 20 × 20 µm2. The holes make it possible to measure in a liquid environment. With a lithography optimization, holes as small as 3 × 3 µm2 can be opened. Further on, an isotropic Si etch step is inserted into the fabrication sequence to ensure a high release yield of the devices (percentage of usable/not broken chips compared to the amount of released chips). With this etch the cantilever structures are under-etched before they are released by tweezers and the release yield is enhanced from 41.5% to 84.0%. In a continuous flow mode, the deflection of the cantilevers is directly proportional to the flow rate. By tuning the design of the integrated grid (hole size, hole-to-hole distance, amount of holes, etc) the sensitivity of the sensor can be changed.

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Section: Introductionmentioning

confidence: 99%

Fabrication of a cantilever-based microfluidic flow meter with nL min⁻¹resolution

Noeth

Keller

Boisen

2010

J. Micromech. Microeng.

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“…Due to the small sample volumes and the low flow rates a flow sensor with a high sensitivity is required. Various types of flow sensors with potential for integration in microfluidic systems have been proposed [ 5 , 7 ], such as thermal anemometers [ 8 – 12 ], optical devices [ 13 – 14 ], pressure-based sensors [ 15 – 18 ] or sensors based on electrical admittance [ 19 – 21 ]. Recently, cantilever-based flow meters have been presented.…”

Section: Introductionmentioning

confidence: 99%

Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

Noeth

Keller

Boisen

2013

Sensors

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For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different materials (SU-8 and SiN) and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external pumps connected to the microfluidic system.

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Velocity Measurement for Moving Surfaces by Using Spatial Filtering Technique Based on Array Detectors

Schaeper

Damaschke

2011

Autonomous and Intelligent Systems

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Micro-flow metering and viscosity measurement of low viscosity Newtonian fluids using a fibreoptical spatial filter technique

Cited by 9 publications

References 6 publications

Fabrication of a cantilever-based microfluidic flow meter with nL min⁻¹resolution

Fabrication of a cantilever-based microfluidic flow meter with nL min⁻¹resolution

Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

Velocity Measurement for Moving Surfaces by Using Spatial Filtering Technique Based on Array Detectors

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Micro-flow metering and viscosity measurement of low viscosity Newtonian fluids using a fibreoptical spatial filter technique

Cited by 9 publications

References 6 publications

Fabrication of a cantilever-based microfluidic flow meter with nL min−1resolution

Fabrication of a cantilever-based microfluidic flow meter with nL min−1resolution

Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

Velocity Measurement for Moving Surfaces by Using Spatial Filtering Technique Based on Array Detectors

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Product

Resources

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Fabrication of a cantilever-based microfluidic flow meter with nL min⁻¹resolution

Fabrication of a cantilever-based microfluidic flow meter with nL min⁻¹resolution