dynasonics TFXL series, Руководство по эксплуатации и техническому обслуживанию

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Rev. 01/11 - 2.4 - TFXL-X
TFXL transit time flow meters are sold with four different transducer
types: DTTN, DTTH, DTTS and DTTC. Meters that utilize DTTN
and DTTH transducers consist of two separate sensors that function
as both ultrasonic transmitters and receivers. DTTS and DTTC
transducers integrate both the transmitter and receiver into one
assembly that fixes the separation of the piezoelectric elements.
DTTN and DTTH transducers are clamped on the outside of a
closed pipe
at a specific distance from each other . The
transducers can be mounted in V-Mount where the sound
transverses the pipe two times, W-Mount where the sound
transverses the pipe four times, or in Z-Mount where the
transducers are mounted on opposite sides of the pipe and the
sound crosses the pipe once. For further details, reference pictures
located under
Table 2.2 on page 2.5. The appropriate mounting
configuration is based on pipe and liquid characteristics. Selection
of the proper transducer mounting method is not entirely predictable
and many times is an iterative process.
Table 2.2 contains
recommended mounting configurations for common applications.
These recommended configurations may need to be modified for
specific applications if such things as aeration, suspended solids or
poor piping conditions are present. W-Mount provides the longest
sound path length between the transducers—but the weakest signal
strength. Z-Mount provides the strongest signal strength—but has
the shortest sound path length. On pipes smaller than 3 inches (75
mm), it is desirable to have a longer path length so that the
differential time can be measured more accurately. Use of the TFXL
diagnostics in determining the optimum transducer mounting will be
covered later in this section.
PART 2 - TRANSDUCER INSTALLATION
2. Transducer Spacing