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pickoff device.
BYPASS RUN -A properly sized bypass run with suitable blocking valves
may be equipped where an interruption in fluid flow for turbine meters ser-
vicing can not be tolerated.
STRAINER-A strainer, filter and/or air eliminator is recommended to reduce
the potential of fouling or damage Recommended mesh size is at least 100
microns. Finer filters are preferred.
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 contaminants carried along by the fluid stream.
2.4
INSTALLATION
WIRING LAYOUT FOR INTERCONNECTIONS
In considering the interconnections between the flowmeter and the flow
measurement system some attention must be given to anticipated noise
sources and to the coupling of these noise sources to the interconnecting
wiring.
Noise signals may be coupled inductively or capacitively into the wiring bet-
ween the flowmeter and the electronic measuring systems. In general, utiliz-
ing a shielded, twisted pair for the interconnection greatly reduces this
coupling. The shield should be grounded on one end of the cable only. In
general, grounding only on the electronic measuring system is best.
However, even with proper interconnecting cabling cross talk with other
signal lines or power lines may still occur and should be avoided. Physical
isolation in the manner in which the wiring is run reduces the chance of
potential problems.
B
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
-In general, the meter run should be chosen to have the same
inner diameter as the meter bore. A minimum of IO pipe diameters of
straight pipe upstream and 5 pipe diameters downstream are required.
Where this optimum line configuration can not be implemented, it is ad-
visable to install a flow straightener properly positioned upstream of the
flowmeter. Orientation is not a critical factor, however, horizontal is a pre-
ferred orientation.
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, solinoids, transformers and power lines
which may be coupled to the
preceeding and following the
flowmeter is termed the meter run.
METER RUN
The piping configuration immediately
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