flowmålere

Flowmålere, or flowmeters, are devices that measure the rate at which fluids move through a conduit. They can provide volumetric flow rate (for example m3/s or L/min) or mass flow rate (kg/s). They are used for liquids and gases in closed pipes as well as in open channels.

Common measurement principles and types include differential-pressure meters (such as orifice plates, Venturi tubes, and flow nozzles), positive-displacement meters, and velocity or hybrid meters (turbine, vortex, ultrasonic, and electromagnetic meters). Mass-flow meters such as Coriolis and thermal meters provide direct or inferred mass flow. Open-channel meters, including weirs and flumes, measure discharge in non-pressurized channels.

Applications span many industries, including water and wastewater, oil and gas, chemical processing, power generation, food and beverage, pharmaceuticals, and HVAC systems. The choice of meter depends on fluid properties, required accuracy, installation conditions, and cost.

Performance and deployment considerations include typical accuracy ranges from about ±0.5% to ±2% of reading for many industrial meters, with higher precision available for specialized devices like Coriolis meters. Calibration and traceability to standards are important for custody transfer and quality assurance. Installation factors such as upstream and downstream straight pipe lengths, temperature and pressure conditions, viscosity, conductivity (for electromagnetic meters), wetted-material compatibility, and maintenance needs all influence performance.

Standards and guidelines commonly referenced in flow measurement include ISO 5167 for differential-pressure meters and API MPMS for petroleum liquids, along with regional or industry-specific specifications. Flowmeters support process monitoring, optimization, energy management, and billing in modern facilities.