Dynasonics TFXM Series Ultrasonic Multi-Channel Flow Meter - Manual (Page 16)

Rev. 8/02
- 2.1 - TFXM
The transducers that are utilized by the Series TFXM contain
piezoelectric crystals for transmitting and receiving ultrasound
signals through walls of liquid piping systems. DTTN and
DTTH transducers are relatively simple and straight-forward to
install, but spacing and alignment of the transducers is critical to
the system's accuracy and performance. Extra care should be
taken to ensure that these instructions are carefully executed.
Mounting of the DTTN and DTTH clamp-on ultrasonic transit
time transducers is comprised of four steps. In general, these
steps consist of:
1. Selection of the optimum location on a piping system.
2. Entering the pipe and liquid parameters into either the
optional software utility (UltraLink) or keying in the
parameters into the TFXM keypad. The software embedded
in UltraLink and TFXM will calculate proper transducer
spacing based on these entries.
3. Pipe preparation and transducer mounting.
The first step in the installation process is the selection of an
optimum location for the flow measurement to be made. For
this to be done effectively, a basic knowledge of the piping
system and its plumbing are required.
An optimum location would be defined as a piping system that
is completely full of liquid when measurements are being taken
and has lengths of straight pipe such as those described in
TABLE 2.1. The optimum straight pipe diameter
recommendations apply to pipes in both horizontal and vertical
orientation.
TFXM transit time flowmeters utilize two transducers that
function as both ultrasonic transmitters and receivers. The
transducers are clamped on the outside of a closed pipe at a
specific distance from each other. The transducers can be
mounted in V-mode where the sound traverses the pipe two
times, W-mode where the sound traverses the pipe four times,
or in Z-mode where the transducers are mounted on opposite
PART 2 - TRANSDUCER POSITIONING
General
1. Mounting Location