3410 Series Gas Ultrasonic Meters Operations Manual
Section 4: Flow measurement
3-9000-777 Rev E
January 2018
17
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Section 4: Flow measurement
Daniel 3410 Gas Ultrasonic Flow Meters measure the transit times of ultrasonic pulses passing
through the medium on two parallel planes. The measurement paths (also referred to as
“chords”) are angled to the pipe axis, and each chord has two transducers acting alternately as
transmitter and receiver as shown in
Figure 4-1
. This permits the transit times to be measured
both with and against the flow (upstream and downstream).
The transducers are mounted on the meter body at accurately known locations for each pipe
size so the distance L between opposing transducers and the angle are precisely defined for the
measurement path.
Figure 4-1 Model 3414 Transit-time measurement principle
