BE6000 Ultrasonic Flow Meter O&M Manual
Flomotion Systems, Inc. ~ FlomotionSystems.com
7
3. Operation Principle
This time-of-travel (transit-time) meter has a pair of transducers mounted on each side of the pipe. The
configuration is such that the sound waves traveling between the devices are at a 45- degree angle to the
direction of liquid flow. The speed of the sound signal traveling between the transducers increases or
decreases depending upon the direction of transmission and the velocity of the liquid being measured. A
time-differential relationship proportional to the flow can be obtained by transmitting the signal alternately in
both directions.
As per equation (1) and (2) above, the velocity of flow is
calculated as below;
The ultrasonic transit-time method is suitable for measuring single-phase, pure liquids without entrained air
bubbles. In industrial sites, the liquids may contain a certain level of impurities and flow conditions are often
not very uniform, thereby negatively affecting the performance of the ultrasonic flow meters. But our BE6000
ultrasonic flow meter adopts the most advanced direct time measuring method that considers the influence of
temperature and crude inside pipe situation in order to increase the accuracy and the reliability of the result.
With the use of the zero setting function, the meter renders 0.5% accuracy.
Where
M- travel times
D- inner diameter of the pipe
θ
transmission angle
C
0
- sound velocity in a static fluid
T
UP
- upstream travel time (reverse flow
direction)
T
DOWN
- downstream travel
time(flow direction)
Δ
T- difference of travel time between
downstream and upstream
