Ultraäänivirtausmittaus

Ultraäänivirtausmittaus, often referred to as ultrasonic flow measurement, is a non-intrusive method used to determine the flow rate of liquids or gases in a pipe. This technique relies on the principle of Doppler effect or transit time differences.

Doppler flow meters utilize the change in frequency of sound waves reflected off moving particles or bubbles within the fluid. A transmitter emits an ultrasonic beam into the fluid, and a receiver detects the reflected waves. If the fluid is moving, the reflected waves will have a different frequency than the emitted waves, with the difference directly proportional to the fluid's velocity. This method requires the presence of reflective particles or bubbles in the fluid.

Transit-time flow meters, on the other hand, measure the time it takes for an ultrasonic pulse to travel through the fluid in both the upstream and downstream directions. Two transducers are used, positioned diagonally across the pipe. When the fluid is flowing, the ultrasonic pulse traveling with the flow will arrive sooner than the pulse traveling against the flow. The difference in transit times is proportional to the average velocity of the fluid. This method is suitable for clean liquids and gases.

The primary advantages of ultrasonic flow measurement include its non-intrusive nature, meaning no part of the meter obstructs the flow, leading to no pressure drop. They are also capable of measuring a wide range of fluid types and flow rates, and can be installed on existing pipelines without cutting them. However, accuracy can be affected by factors such as fluid properties, pipe wall thickness, and the presence of air bubbles or solids, depending on the specific technology used.