Micro Coriolis Mass Flow Sensor with Piezoelectric Transducers for Both Actuation and Readout

We have realized a micro Coriolis mass flow sensor with piezoelectric transducers for both actuation and readout, resulting in lower power consumption and improved robustness to shock in comparison to the current actuation and readout methods. The PZT thin film in the parallel plate piezoelectric transducers was deposited by pulsed laser deposition (PLD). This paper presents the design, fabrication process and initial characterization results with mass flow of water and nitrogen.</p

Air Damping Analysis of a Micro-Coriolis Mass Flow Sensor

A micro-Coriolis mass flow sensor is a resonating device that measures small mass flows of fluid. A large vibration amplitude is desired as the Coriolis forces due to mass flow and, accordingly, the signal-to-noise ratio, are directly proportional to the vibration amplitude. Therefore, it is important to maximize the quality factor Q so that a large vibration amplitude can be achieved without requiring high actuation voltages and high power consumption. This paper presents an investigation of the Q factor of different devices in different resonant modes. Q factors were measured both at atmospheric pressure and in vacuum. The measurement results are compared with theoretical predictions. In the atmospheric environment, the Q factor increases when the resonance frequency increases. When reducing the pressure from 1 bar to 0.1 bar, the Q factor almost doubles. At even lower pressures, the Q factor is inversely proportional to the pressure until intrinsic effects start to dominate, resulting in a maximum Q factor of approximately 7200.</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

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

A versatile technology platform for microfluidic handling systems, part I:fabrication and functionalization

Many microfluidic devices are made using specialized fabrication processes, limiting the ability to integrate those devices on the same chip. In this paper, a versatile technology platform is presented that allows for integration of many different devices. It provides a method to design channels in a wide range of sizes and shapes with different functionalization options in close proximity to the fluid in the channels. The latter includes release of the channels for thermal isolation or mechanical movement and metal or piezoelectric layers for actuation and read-out. The channel walls are made using silicon-rich silicon nitride to provide durable, strong, chemically inert and thermally stable channels directly below the substrate surface

Integrated thermal and microcoriolis flow sensing system with a dynamic flow range of more than five decades

We have realized a micromachined single chip flow sensing system with an ultra-wide dynamic flow range of more than five decades, from 100 nL/h up to more than 10 mL/h. The system comprises both a thermal and a micro Coriolis flow sensor with partially overlapping flow ranges

An integrated optical method to readout µ-Coriolis mass flow sensors

This paper presents a novel readout for a µ-Coriolis mass flow sensor based on a differential optical reflective method, using a vertical-cavity surface-emitting laser (VCSEL) and two photodiodes (PD). The new readout detects change in applied mass flow rate by measuring the phase shift between the two photodiode signals. Such a setup offers a non-contact and robust sensing method. Measurements are presented for mass flow of DI-water up to 10 gram/hour resulting in a phase shift of 8.7 degrees.</p

Thermal Flow Meter with Integrated Thermal Conductivity Sensor

This paper presents a novel gas-independent thermal flow sensor chip featuring three calorimetric flow sensors for measuring flow profile and direction within a tube, along with a single-wire flow independent thermal conductivity sensor capable of identifying the gas type through a simple DC voltage measurement. All wires have the same dimensions of 2000 (Formula presented.) m in length, 5 (Formula presented.) m in width, and 1.2 (Formula presented.) m in thickness. The design theory and COMSOL simulation are discussed and compared with the measurement results. The sensor’s efficacy is demonstrated with different gases, He, N2, Ar, and CO2, for thermal conductivity and thermal flow measurements. The sensor can accurately measure the thermal conductivity of various gases, including air, enabling correction of flow rate measurements based on the fluid type. The measured voltage from the thermal conductivity sensor for air corresponds to a calculated thermal conductivity of 0.02522 [W/m·K], with an error within 2.9%.</p

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