AQUA M A STE R4
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EL EC T R O M AG N E T I C FLO W M E T ER I N SER T I O N SEN S O R | O I/FE W4 0 0/A P - EN R E V. B
11
Cable routing
IMPORTANT NOTE
Do not join signal cable to increase cable length. Use
single lengths of cable only.
The cable to the insertion sensor must be installed neatly or
within a conduit. Both loose or conduit installations must have
a u-bend below terminal connection box height to enable any
water to run off thus avoiding any capillary action into the
insertion sensor.
Figure 11 Cable routing to enable water run off
Observe the following points when routing signal cables:
• Keep the remote form insertion sensor cable as short as
possible to avoid unnecessary electrical and magnetic
pickup. Lengths* up to 150 m (492 ft) are permitted, but
are more susceptible to unwanted pickup.
• Avoid routing the cable in the vicinity of electrical
equipment or switching elements that can create stray
fields, switching pulses and induction.
• Avoid running insertion sensor cables adjacent to those
from other electromagnetic flowmeters, especially in the
same cable ducts as unwanted magnetic coupling can
induce unwanted signals and cause incorrect operation of
the insertion sensor. Ideally adjacent cables should be >200
mm (8 in) apart.
• Do not damage the sheathing of the cable during
installation.
• Ensure that a drip loop (water trap) is used when installing
the connecting cables for the insertion sensor.
*
Sensus
TM
cable is available in 5 and 20 m (15 and 65 ft) lengths.
Renewable energy cable is available as a 10 m (30 ft) length.
Localized heating/welding
The insertion sensor must not be submitted to localized
heating during installation; remember this is a measuring
instrument.
Figure 12 Localized heat
Tapping on pipelines
An insertion sensor is inserted into a flow-line through a small
tapping and a valve fitted to the line. The tapping can be as
small as one inch BSP or larger. Such a tapping is common on
pipelines and, if one does not exist where it is required to make
the installation, it is very inexpensive to fit one, online and
under pressure, and there are many specialist companies that
do this type of work.
WARNING – RISK OF INJURY DUE TO PRESSURIZED
VESSEL
It is important to note that putting any type of device
into a pressurized vessel (the pipe) can be dangerous.
If the pressure in the line is high (typically 5 bar or
more), care must be used in both installing and
removing the insertion sensor. If the pressure is
greater than 10 bar, installation (or removal) of a
insertion sensor is not recommended. Instead the
pressure should be removed from the line for the
short period of time it takes to install or remove the
insertion sensor, when the pressure can then be re-
applied. In many instances, the removal of a insertion
sensor from a line is more dangerous than the
installation. For this reason, the insertion sensor is
supplied complete with a safety mechanism (see page
16) that prevents rapid outward movement and
potential injury to operators. It must be stressed that
this is a problem with all insertion sensor types, not
just the insertion sensor.
