Proper application of the turbine flowmeter requires a suitable
piping installation in order to achieve accurate and reliable
operation. (Refer to Figure 1).
The piping configuration immediately preceding and following
the flowmeter is termed the meter run. Refer to the flowmeter's
operators manual when installing the flowmeter and meter run.
RELATIVE - The performance of the turbine flowmeter is
affected by fluid swirl and non-uniform velocity profiles. The
following recommendation will reduce such flow irregularities.
It is advisable not to locate the meter run immediately
downstream of pumps, partially opened valves, bends or other
similar piping configurations. In addition, the area surrounding
the flowmeter should be free of sources of electrical noise such
as motors, solenoids, transformers and power lines which may
be coupled to the pickoff device.
The metering section should not be subjected to excessive
vibration or shock. Such a condition may result in a
mechanically induced output signal from the pickoff device.
METER RUN - In general, the meter run should be chosen to
have the same inner diameter as the meter bore. A minimum of
10 pipe diameters of straight pipe up stream and 5 pipe
diameters downstream are required. Where this optimum line
configuration can not be implemented, it is advisable to install a
flow straightener properly positioned upstream of the f
lowmeter. Orientation is not a critical factor, however,
horizontal is a preferred orientation.
BYPASS RUN - A properly sized bypass run with suitable
blocking valves may be equipped where an interruption in fluid
flow for turbine meters servicing can not be tolerated.
STRAINER - A strainer, filter and/or air eliminator is
recommended to reduce the potential of fouling or damage.
On initial startup of a line, it is advisable to install a spool piece
purging the line to eliminate damaging the flowmeter, due to
flux, tape, solder, welds or other contaminates carried along by
the fluid stream.
CAVITATION - Cavitation causes measurement inaccuracies in
turbine flowmeters and should be avoided by suitable line and
Figure 1. Typical Flowmeter Installation