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PART 2 - TRANSDUCER INSTALLATION
General
The FST transducers contain piezoelectric crystals for transmitting and receiving
ultrasonic signals through walls of liquid piping systems. FST transducers are
relatively simple and straightforward to install, but spacing and alignment of the
transducers is critical to the system's accuracy and performance. Take care to ensure
that these instructions are carefully executed. FST1, FST2, and FST3 small pipe
transducers have integrated transmitter and receiver elements that eliminate the
requirement for spacing measurement and alignment.
Mounting of the FST4 and FST5 clamp-on ultrasonic transit time transducers is a
three-step process:
1. Select the optimum location on a piping system.
2. Enter the pipe and liquid parameters into either the software utility or key the
parameters into the transmitter using the keypad. The software utility or the
monitor's firmware calculates proper transducer spacing based on these entries.
3. Pipe preparation and transducer mounting.
BTU meters require two RTDs to measure heat usage. The flow meter utilizes 1,000 Ω,
three-wire, platinum RTDs in two mounting styles. Surface mount RTDs are available
for use on well insulated pipes. Mounting the RTD in an uninsulated area causes
inconsistent temperature readings. Insertion (wetted) RTDs should be sued in these
areas instead.
Step 1 - Mounting Location
The first step in the installation process is the selection of an optimum location for
the flow measurement to be made. This requires a basic knowledge of the piping
system and its plumbing.
An optimum location is defined as:
• A piping system that is completely full of liquid when measurements are
being taken. The pipe may become completely empty during a process
cycle, which results in the error code 0010 (Low Signal Strength) being
displayed on the flow meter while the pipe is empty. This error code clears
automatically once the pipe refills with liquid. It is not recommended to
mount the transducers in an area where the pipe may become partially
filled. Partially filled pipes cause erroneous and unpredictable operation
of the meter.
• A piping system that contains 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. The straight runs in Table 2.1 apply to liquid velocities that
are nominally 7 FPS (2.2 MPS). As liquid velocity increases above this
nominal rate, the requirement for straight pipe increases proportionally.
• Mount the transducers in an area where they will not be inadvertently
bumped or disturbed during normal operation.
• Avoid installations on downward flowing pipes unless adequate
downstream head pressure is present to overcome partial filling of or
cavitation in the pipe.
• Note: Do not cut transducer cables to alter length. This will
void the factory warranty. Cables are available in several
lengths. Assess the installation location prior to ordering to
determine the optimum length. If the wrong length is ordered,
contact the factory.
Z205739-0D
PAGE 9
Alta Labs, Enercept, Enspector, Hawkeye, Trustat, Aerospond, Veris, and the Veris 'V' logo are trademarks or registered trademarks of Veris Industries, L.L.C. in the USA and/or other countries.
FSRxxxx SERIES
©2013 Veris Industries
INSTALLATION GUIDE
Piping Configuration and Transducer Positioning
Flow
*
Flow
*
**
Flow
*
Flow
*
Flow
*
Flow
*
Table 2.1 - Piping Configuration and Transducer Positioning
The flow meter system provides repeatable measurements on piping systems that do
not meet these requirements, but accuracy of these readings may be influenced to
various degrees.
Step 2 - Transducer Spacing
Transit time flow meters can be used with two different transducer types. Meters
that utilize the FST4 and FST5 transducer sets consist of two separate sensors
that function as both ultrasonic transmitters and receivers. FST1, FST2, and FST3
transducers integrate both the transmitter and receiver into one assembly that fixes
the separation of the piezoelectric crystals. These transducers are clamped on the
outside of a closed pipe at a specific distance from each other.
The FST4 and FST5 transducers can be mounted in:
W-Mount where the sound traverses the pipe four times. This mounting
method produces the best relative travel time values but the weakest signal
strength.
V-Mount where the sound traverses the pipe twice. V-Mount is a compromise
between travel time and signal strength.
Z-Mount where the transducers are mounted on opposite sides of the pipe
and the sound crosses the pipe once. Z-Mount will yield the best signal
strength but the smallest relative travel time.
Upstream
Downstream
Pipe
Diameters
Diameters
*
**
25
5
**
14
5
10
5
**
10
5
**
10
5
**
24
5
**
Pipe
05131
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