A Coriolis flow meter is a type of flow meter that measures the flow rate of fluids by utilizing the Coriolis effect. It operates based on the principle that when a fluid flows through a vibrating tube, the fluid’s mass causes the tube to twist or oscillate, and this motion is directly proportional to the mass flow rate.
Working principle of a Coriolis flow meter:
- Vibrating Tube: The core component of a Coriolis flow meter is a U-shaped tube that is typically made of metal and is mounted in a flow path. The tube is designed to vibrate in a specific frequency and mode, such as torsional or dual-curved.
- Fluid Flow: The fluid whose flow rate is being measured is directed into the vibrating tube. It enters one side of the U-shaped tube and exits from the other side, causing it to pass through the vibrating region.
- Coriolis Effect: As the fluid flows through the vibrating tube, it experiences a Coriolis force due to its inertia. The Coriolis force causes the tube to twist or deform in proportion to the mass flow rate of the fluid.
- Phase Shift Measurement: The Coriolis flow meter measures the phase shift between the input and output vibrations of the tube. The phase shift is caused by the twisting or oscillation of the tube due to the Coriolis effect.
- Mass Flow Calculation: The measured phase shift is then converted into a mass flow rate value using calibration factors specific to the flow meter. Since the phase shift is directly related to the mass flow rate, the flow meter can accurately determine the fluid’s flow rate.
- Additional Measurements: Coriolis flow meters can also provide additional measurements, such as density and temperature. By analyzing the changes in the tube’s vibration characteristics, the flow meter can determine the fluid’s density and temperature simultaneously.
- Display and Output: The calculated mass flow rate, density, and temperature values can be displayed on the flow meter’s local display or transmitted to external devices for further processing or recording. Common output signals include analog (e.g., 4-20 mA) or digital (e.g., Modbus) signals.
Below are the applications where Coriolis flow meters are widely used:
- Oil and Gas: Coriolis flow meters are commonly employed in the oil and gas industry for measuring the flow rate of crude oil, refined petroleum products, natural gas, and various process gases. They are utilized in production, transportation, and refining processes.
- Chemical Processing: In chemical plants, Coriolis flow meters are used to monitor and control the flow of various chemicals, including corrosive substances, solvents, acids, and bases. They provide accurate measurements for process control, batching, blending, and custody transfer applications.
- Food and Beverage: Coriolis flow meters play a crucial role in the food and beverage industry, where accurate flow measurement is essential for production and quality control. They are used for measuring ingredients, such as liquid additives, flavorings, syrups, and dairy products, as well as for monitoring the flow of beverages during bottling and packaging.
- Pharmaceutical and Biotechnology: Coriolis flow meters are utilized in pharmaceutical and biotechnology processes for measuring the flow of liquids, including active pharmaceutical ingredients (APIs), solvents, buffers, and media. They are often integrated into sterile and sanitary systems due to their hygienic design and their ability to provide accurate measurements in critical processes.
- Water and Wastewater: Municipal water treatment plants and wastewater treatment facilities use Coriolis flow meters for measuring the flow of water, chemicals, and sludge. They are employed in applications such as dosing control, leak detection, flow monitoring, and custody transfer of water and wastewater.
- Power Generation: Coriolis flow meters are found in power plants to measure the flow rate of fuels, such as natural gas, diesel, and heavy fuel oil, as well as cooling water and other process fluids. They ensure accurate fuel consumption measurements, assist in emissions control, and help optimize energy efficiency.
- HVAC and Building Automation: Coriolis flow meters are utilized in heating, ventilation, and air conditioning (HVAC) systems to measure the flow of water or glycol-based fluids, ensuring proper temperature control and energy management in commercial and residential buildings.
- Pulp and Paper: In the pulp and paper industry, Coriolis flow meters are used for measuring the flow of chemicals, additives, and process fluids, such as pulp slurry, black liquor, and bleaching agents. They assist in optimizing chemical usage, controlling process parameters, and ensuring product quality.