Flow measurement
Flow measurement determines the volume or mass of fluid passing a point per unit time, or the total quantity passing during an interval.
Differential pressure flow meter: A flow meter that infers fluid flow from the pressure difference across a restriction in a pipe. Orifice plates and venturi tubes convert flow speed into a measurable pressure difference.
Volumetric flow rate: The volume of fluid passing a cross-section per unit time. Many meters report this rate, often in cubic metres per second or litres per minute.
Water metering: The measurement of water consumption, commonly for billing, monitoring, or resource management. Utility meters total delivered water, often using mechanical, electromagnetic, or ultrasonic methods.
Flow measurement uncertainty: The quantified doubt associated with a reported flow measurement. Installation effects, calibration, and changing flow conditions limit the certainty of meter readings.
Electromagnetic flow meter: A meter that measures conductive-fluid velocity from the voltage induced as fluid crosses a magnetic field. It measures flow without placing a restriction or moving part in the stream.
Mass flow rate: The mass of fluid passing a cross-section per unit time. Mass flow avoids ambiguity when fluid density changes with temperature or pressure.
Custody transfer: The measurement of a commodity exchanged between parties for accounting or payment. Hydrocarbon flow measurements determine quantities transferred between producers, transporters, and buyers.
Pitot tube: A probe that measures local fluid speed from the difference between stagnation and static pressure. Unlike a full-flow meter, it samples velocity at a point and often needs a profile survey.
Ultrasonic flow meter: A meter that uses sound waves to determine fluid velocity or flow in a conduit. Transit-time and Doppler designs infer flow from how sound travels through moving fluid.
Flow velocity: The speed and direction of fluid motion at a location. Velocity profiles determine how a point measurement relates to total flow through a pipe.