Emerson Daniel 3415

4 Measurement
Topics covered in this chapter:
•
Flow measurement
•
Signal processing
•
Acquisition mode
•
Chord gas and sound velocity measurements
•
Volumetric flow rate
•
3410 Series gas flow meter characterizations
4.1 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.
Models 3415, 3416, and 3417 consist of two meters in one body. Transmitter head 1 for all
models controls 4 direct transducer paths. Transmitter head 2 for the 3415 and 3416
controls 1 or 2 reflective paths. Transmitter head 2 for the 3417 controls 4 direct paths
that are a mirror image of transmitter head 1.
Measurement
Operations manual 15