Compact Micro-Coriolis Mass-Flow Meter with Optical Readout

This paper presents the first nickel-plated micro-Coriolis mass-flow sensor with integrated optical readout. The sensor consists of a freely suspended tube made of electroplated nickel with a total length of 60 mm, an inner diameter of 580 µm, and a wall thickness of approximately 8 µm. The U-shaped tube is actuated by Lorentz forces. An optical readout consisting of two LEDs and two phototransistors is used to detect the tube motion. Mass-flow measurements were performed at room temperature with water and isopropyl alcohol for flows up to 200 g/h and 100 g/h, respectively. The measured resonance frequencies were 1.67 kHz and 738 Hz for water and 1.70 kHz and 752 Hz for isopropyl alcohol for the twist and swing modes, respectively. The measured phase shift between the two readout signals shows a linear response to mass flow with very similar sensitivities for water and isopropyl alcohol of (Formula presented.) and (Formula presented.), respectively.</p

Modeling, Fabrication, and Testing of a 3D-Printed Coriolis Mass Flow Sensor

This paper presents the modeling, fabrication, and testing of a 3D-printed Coriolis mass flow sensor. The sensor contains a free-standing tube with a circular cross-section printed using the LCD 3D-printing technique. The tube has a total length of 42 mm, an inner diameter of about 900 µm, and a wall thickness of approximately 230 µm. The outer surface of the tube is metalized using a Cu plating process, resulting in a low electrical resistance of 0.5 Ω. The tube is brought into vibration using an AC current in combination with a magnetic field from a permanent magnet. The displacement of the tube is detected using a laser Doppler vibrometer (LDV) that is part of a Polytec MSA-600 microsystem analyzer. The Coriolis mass flow sensor has been tested over a flow range of 0–150 g/h for water, 0–38 g/h for isopropyl alcohol (IPA), and 0–50 g/h for nitrogen. The maximum flow rates of water and IPA resulted in less than a 30 mbar pressure drop. The pressure drop at the maximum flow rate of nitrogen is 250 mbar.</p

Free Suspended Thin-Walled Nickel Electroplated Tubes for Microfluidic Density and Mass Flow Sensors

In this paper, a novel fabrication method is proposed for microfluidic tubes with a large diameter, circular cross-section, and thin wall. These properties make the tubesespecially suitable for density sensors and Coriolis mass flow sensors, because of the resulting low tube mass, low-pressure drop, and low pressure-dependence of the tube shape. A demonstrator sensor was fabricated and the first measurement results of fluid density and mass flow are presented. The low-cost fabrication method is based on electroplating technology and results in tubes with a near-perfect circular cross-section. Diameters ranging from 120 µm to 1 mm and wall thicknesses from 8 µm to 60 µmhave been achieved. For the demonstrator sensor presented in this paper a freely suspended tube was realized with a total length of 37 mm, a diameter of 600 µm, and a wallthickness of 20 µm. Density measurements were performed using various gases, liquids, and liquid mixtures at 21◦C to 23◦C lab temperature. The accuracy of the measured densities of gases such as nitrogen, argon, and helium is 5%. For liquids including DI water, isopropyl alcohol (IPA), and their various mixtures an accuracy of 0.5% was obtained. Preliminary mass flow rate measurements were performed with water and isopropyl alcohol up to 30 g/h with less than 30 mbar pressure drop thanks to the large tube diameter

Cylindrical tubes with large diameters and thin walls for application in microfluidic density and mass flow sensors

In the past, numerous density and flow sensors have been presented for a large variety of applications. Over time, with emerging new applications monitoring of very small flow rates, and detection of fluid composition have become even more important. Almost three decades ago, the first micromachined density and Coriolis mass flow sensor was introduced. This sensor was based on a freely suspended vibrating channel. Over the years, to improve the performance of the microfluidic sensor, different fabrication methods based on silicon micromachining techniques were proposed. All these fabrication methods lead to a freely suspended channel with a non-circular cross-sectional shape, and a limited range of wall thicknesses and cross-sectional areas, which leads to a limited flow range and pressure dependency of the sensor. To overcome these drawbacks, this research aims to improve the range of channel diameters of a circular shape and a relatively thin, chemically inert channel wall. This research is divided into three different sections. The first part of the research focuses on a literature review to investigate all the different fabrication methods already used to realize a freely suspended channel. The second part of the research focuses on fabricating freely suspended tubes based on the three most promising potential fabrication methods that do not require the frequently used silicon micromachining techniques. In this section, each fabrication method is further investigated and discussed in detail to find out the possibility of achieving such a tube with a circular cross-sectional shape and a high ratio of the diameter to wall thickness. In the third section, each tube that has been realized is tested in practice and the measurement results are compared to a numerical model. This numerical model has been made to model the mechanical behavior of the tube when a medium is flowing through the tube. The results show a significant improvement in the range of the mass flow and dependency of the performance of the sensor on the input pressure. Furthermore, a demonstrator is proposed with an integrated optical readout which improves the stability of the output signal regarding the mass flow rate

3D printed Coriolis mass flow sensor

This paper presents the first 3D printed Coriolis mass flow sensor that has been tested using water flow from 0 to 150 g/h. The sensor consists of a free-standing tube printed by an LCD 3D printing technique. The outer tube surface is metalized by copper plating to allow for the actuation of the tube by Lorenz forces. The displacement of the tube is detected by a laser doppler vibrometer (LDV). The tube has a circular cross-section with an inner diameter and wall thickness of approximately 900 μm and 230 μm, respectively. The relatively large diameter results in a low-pressure drop of 30 mbar at water flow of 150 g/h

Thin-Walled Cylindrical Nickel Electroplated Tubes for Application in Microfluidic Density and Mass Flow Sensors

In this paper, a novel fabrication method is proposed for microfluidic tube with a large diameter, circular cross-section and a thin wall. These properties make the tubes especially suitable for fluid density sensors and Coriolis mass flow sensors, because of the resulting low tube mass, low pressure drop and low pressure-dependence of the tube shape. A demonstrator sensor was fabricated and first measurement results of fluid density and mass flow are presented. The low-cost fabrication method is based on electroplating technology and results in tubes with a near-perfect circular cross section. Diameters ranging from 120 m to 1 mm and wall thicknesses from 8 m to 60 m have been achieved. For the demonstrator sensor presented in this paper a freely suspended tube was realized with a total length of 37 mm, a diameter of 600 m, and a wall thickness of 20 m. Density measurements were performed on nitrogen, ethanol, water, isopropyl alcohol (IPA), and various mixtures at 21°C-23°C lab temperature. Mass flow rate was measured up to 30 g/h with less than 30 mbar pressure drop thanks to the large tube diameter

Towards integrated circular flow tubes with large diameter

In this paper we propose two novel methods for the fabrication of microfluidic channels with circular cross-section and a relatively large diameter in the range of 300 to 1000 µm. The aim is to use such channels in a micro Coriolis mass flow sensor as an alternative to the well-known Surface Channel Technology (SCT). One method is based on sol-gel technology, where PDMS mold is coated with silicon oxide to form the channel wall. The other method involves electroplating of a opper or nickel channel wall around a wire of ABS

Modeling, Fabrication, and Testing of a 3D-Printed Coriolis Mass Flow Sensor

This paper presents the modeling, fabrication, and testing of a 3D-printed Coriolis mass flow sensor. The sensor contains a free-standing tube with a circular cross-section printed using the LCD 3D-printing technique. The tube has a total length of 42 mm, an inner diameter of about 900 µm, and a wall thickness of approximately 230 µm. The outer surface of the tube is metalized using a Cu plating process, resulting in a low electrical resistance of 0.5 Ω. The tube is brought into vibration using an AC current in combination with a magnetic field from a permanent magnet. The displacement of the tube is detected using a laser Doppler vibrometer (LDV) that is part of a Polytec MSA-600 microsystem analyzer. The Coriolis mass flow sensor has been tested over a flow range of 0–150 g/h for water, 0–38 g/h for isopropyl alcohol (IPA), and 0–50 g/h for nitrogen. The maximum flow rates of water and IPA resulted in less than a 30 mbar pressure drop. The pressure drop at the maximum flow rate of nitrogen is 250 mbar

Measurement of viscosity for medicine mixture

In this paper we discuss a multi-parameter microfluidic chip, in the intent of measuring the viscosity of medicinal binary mixtures. The measurement is based on the Hagen-Poiseuille equation, where the viscosity is function of mass flow and pressure drop. For different liquids and liquid mixtures, the viscosity measured is close to that in literature