Dynasonics DXN Portable Ultrasonic Measurement System - Manual (Page 22)

Transducer Mount Mode Transducer Pipe Material Pipe Size
W-Mount
DTTSU
Plastic (all types)
0.5…0.75" (12.7…19 mm)
Carbon Steel
Stainless Steel
Copper
Galvanized Not recommended
V-Mount
Plastic (all types)
0.75…2.4" (19…61 mm)
Carbon Steel
Stainless Steel
Copper
Galvanized 0.5…2.4" (12.7…61 mm)
Table 3: Starting Point Transducer Mounting Modes—DTTSU
For pipes 24" (600 mm) and larger the DTTL transducers using a transmission frequency of 500 KHz are recommended.
DTTL transducers may also be advantageous on pipes 4…24" if there are less quantifiable complicating aspects such as –
sludge, tuberculation, scale, rubber liners, plastic liners, thick mortar, gas bubbles, suspended solids, emulsions, or pipes that
are perhaps partially buried where a V-mount is required/desired, etc.
The DTTN, DTTH and DTTL transducers must be properly oriented and spaced on the pipe to provide optimum reliability and
performance. On horizontal pipes, when Z-Mount is required, the transducers should be mounted 180 radial degrees from
one another and at least 45 degrees from the top-dead-center and bottom-dead-center of the pipe. See Figure 24 . Also see
Z-Mount Configuration . On vertical pipes the orientation is not critical.
The best accuracy is achieved when transducer spacing is exactly what the DXN calculates, so the calculated spacing should
be used if signal quality is satisfactory. If the pipe is not round, the wall thickness not correct or the actual liquid being
measured has a different sound speed than the liquid programmed into the transmitter, the spacing can vary from the
calculated value. If that is the case, the transducers should be placed at the highest signal level observed by moving the
transducers slowly around the mount area.
NOTE: N Transducer spacing is calculated on ideal pipe. Ideal pipe is almost never found so the transducer spacing distances
may need to be altered. An effective way to maximize signal quality is to configure the display to show signal quality,
fix one transducer on the pipe and then starting at the calculated spacing, move the remaining transducer small
distances forward and back to find the maximum signal quality point.
45°
45°
YES YES
45°
45°
TOP OF
PIPE
Figure 24: Transducer Orientation – Horizontal Pipes
The spacing between the transducers is measured between the two spacing marks on the sides of the transducers. These
marks are approximately 0.75" (19 mm) back from the nose of the DTTN and DTTH transducers, and 1.2" (30 mm) back from
the nose of the DTTL transducers. See Figure 25 .
DXN Portable Ultrasonic Measurement System
Page 22 February 2013