SL1188P Ultrasonic transit-time flowmeter
Revision
：
2.0.0
Page
13
of
81
Ensure that the pipe surface temperature at the measuring point is within the transducer temperature limits.
Consider the inside condition of the pipe carefully. If possible, select a section of pipe where the inside is free of
excessive corrosion or scaling.
4.
Transducer Installation
4.1.
Installing the Transducers
Before installing the transducers, clean the pipe surface where the transducers are to be mounted. Remove any rust,
scale or loose paint and make a smooth surface. Apply a wide band of sonic coupling compound down the center
of the face of each transducer as well as on the pipe surface, and then attach the transducers to the pipe with the
straps provided and tighten them securely.
Note:
The two transducers should be mounted at the pipe
’
s centerline on horizontal pipes.
Make sure that the transducer mounting direction is parallel with the flow.
During the installation, there should be no air bubbles or particles between the transducer and the pipe wall. On
horizontal pipes, the transducers should be mounted in the 3 o
’
clock and 9 o
’
clock positions of the pipe section in
order to avoid any air bubbles inside the top portion of the pipe. (Refer to Transducer Mounting). If the
transducers cannot be mounted horizontally symmetrically due to limitation of the local installation conditions, it
may be necessary to mount the transducers at a location where there is a guaranteed full pipe condition (the pipe is
always full of liquid).
4.1.1.
Transducer Spacing
After entering the required parameters, the spacing between the ENDS of the two transducers is considered as the
standard transducer spacing (Refer to Top View on transducer mounting methods). Check the data displayed in
Window M25 and space the transducers accordingly.
4.1.2.
Transducer Mounting Methods
Four transducer mounting methods are available. They are respectively: V method, Z method and N method. The
V method is primarily used on small diameter pipes (DN100~400mm, 4
”
~16
”
). The Z method is used in
applications where the V method cannot work due to poor signal or no signal detected. In addition, the Z method
generally works better on larger diameter pipes (over DN300mm, 12
”
) or cast iron pipes.
The N method is an uncommonly used method. It is used on smaller diameter pipes (below DN50mm, 2
”
).
4.1.3.
V Method
The V method is considered as the standard method. It usually gives a more accurate reading and is used on pipe
diameters ranging from 25mm to 400mm (1~16
”
) approximately. Also, it is convenient to use, but still requires
proper installation of the transducer, contact on the pipe at the pipe
’
s centerline and equal spacing on either side of
the centerline.
Downstream Transducer
Upstream Transducer
Flow
Transducer Space
Flow
Side View
Top View
Section
Pipe Strap
Transducer
