56
Gas measurement
Differential pressure source is located
upper side of main process piping
(within 45
o
upward from vertical direction)
Differential pressure source is located
lower side of main process piping
(within 45
o
downward from horizontal direction)
Differential pressure source is located
upper side of main process piping
(within 45
o
upward from horizontal direction)
Liquid measurement
Steam measurement
Upper
Upper
Lower
45
d
45
d
45
d
45
d
45
d
Lower
45
d
Main process piping
Differential pressure source
Check of high/low pressure transmitter
The detecting unit of the differential pressure transmitter bears symbols H and L which rep-
resent high and low pressure sides, respectively.
Also, vent/drain plugs are provided at the lower process connection, while impulse pipes are
connected at the upper process connections.
Removal of protective cap
The process connection ports of the transmitter and manifold (equalizer) valve are
fi
tted with
protective caps. Before piping, be sure to remove the caps. When removing the caps, care-
fully protect the threaded portion and sealing face from damage.
Connection of transmitter and impulse pipes
(1) When using the manifold valve, it should be
fi
xed to the transmitter by tightening four
oval
fl
ange set bolts (7/16-20UNF), and then the impulse pipe should be connected to
the manifold valve. Tightening torque of 7/16-20UNF mounting bolt should be 30 to 40
N·m (3 to 4 kgf·m).
(2) If a manifold valve is not used, the impulse pipes can directly be screwed into the trans-
mitter. If thread size does not match between the transmitter and impulse pipes, an oval
fl
ange should be used. Tightening torque of 7/16-20UNF mounting bolt in an oval
fl
ange
should be 30 to 40 N·m (3 to 4 kgf·m).
Position of process taps (horizontal main process piping
The position of the process tap is determined by the relationship between the condition,
characteristics and measuring point of the process
fl
uid.
Note the following
fi
gures when planning and installing the piping.
It is generally recognized that there are appropriate positioning relationship between the trans-
mitter and main process piping for accurate measurement to avoid harmful gas or liquid ac-
cumulation.
General recognitions are;
1) Mount transmitter below main process piping for liquid or steam measurement.
2) Mount transmitter above main process piping for gas measurement.
The standard style of FCX-AII series transmitter correspond to the piping procedure 1 men-
tioned above. Change the vent/drain plug to correspond to the piping procedure 2 .
Main valve or manifold used for piping should be selected with the maxi-
mum pressure of the process taken into account (piping parts such as
main valve, etc. should be furnished by user). If the main valve and other
parts do not meet the rating, it may result in leakage of gas or liquid which
could lead to a hazard.
ATTENTION
6.2 Piping
6.2.1 Piping of differential pressure and flow transmitters (type FKC)
