42
..... Z method
The figure below illustrates the final Z method installation.
F
IGURE
4.4-P
4.4.4 WV and WW Methods
For applications with pipe diameters smaller than 2 inches (50 millimeters), the WV and WW methods are
options to achieve higher accuracy and stability when reasonable signal strength can be obtained (10% or
higher).
4.5
Small Pipe Applications
In this section, small pipe applications refer to the following pipe sizes:
•
stainless steel or brass: 1.0 to 3.5 in (25.4 to 88.9 mm)
•
PVC, carbon steel, or other: 1.0 to 2.5 in (25.4 to 63.5 mm)
If signal strength is greater than 10%,
we recommend the W mounting method for pipe sizes 3.5 in (63.5
mm) or smaller and the WW mounting method for pipe sizes 2.0 in (50.8 mm) or smaller.
The pipe curve effect on small pipe applications can cause multipath signals and measurement
uncertainty. Removing extra compound along the transducer sides can eliminate the side wave paths as
seen in
Figure 4.5-A (page 43)
. Follow these steps to eliminate these side wave paths:
1.
Apply coupling compound as usual on to the coupling surfaces, and clamp the transducers onto the
pipe.
2.
Use a pen-sized, standard screwdriver to remove the extra grease between the transducers and the
pipe
(Figure 4.5-A, page 43)
.
