Yokogawa ADMAG AXR - Manual (Page 13)

<3. INSTALLATION>
3-1
IM 01E30D01-01EN
3. INSTALLATION
3.1 Piping Design Precautions
WARNING
Installation of the magnetic flowmeter must
be performed by expert engineer or skilled
personnel. No operator shall be permitted to
perform procedures relating to installation.
IMPORTANT
Design piping correctly, referring to the following
to prevent damage to flowtubes and to assure
accurate measuring.
(1) Location
IMPORTANT
Install the flowmeter in a location where it is
not exposed to direct sunlight. The minimum
ambient temperature is limited by the minimum
fluid temperature of the flowtube. For more
information, refer to Chapter 11 “OUTLINE.” The
flowmeter may be used in an ambient humidity
where the relative humidity ranges from 0 to
100%. However, avoid long-term continuous
operation at relative humidity above 95%.
(2) Noise Avoidance
IMPORTANT
The flowmeter should be installed away from
electrical motors, transformers, inverters
and other power sources in order to avoid
interference with measurement.
(3) Required Lengths of Straight Runs
To maintain accurate measurement, see JIS B7554
“Electro Magnetic Flowmeters” which explains the
requirements for upstream piping conditions of
magnetic flowmeters.
The piping conditions we recommend as shown in
Figure 3.1.1 are based on JIS B7554 and on our
piping condition test data.
When installing two or more magnetic flowmeters
on a single pipe, provide a run of at least 5D
between them.
Gate valve
fully open
Reducer
pipe
5 D or more 2 D or more 2 D or more
2 D or more
10 D or more
10 D or more 5 D or more 5 D or more 0 is allowable 0 is allowable
0 is allowable 0 is allowable
F0301.ai
Tee
90-degree bent
Various valves
Expander
pipe
D: Flowtube Size
Figure 3.1.1 Required Lengths of Straight Runs
*1: Do not install anything in the vicinity that may
interfere with the magnetic field, induced signal
voltages, or flow velocity distributions of the
flowmeter.
*2: A straight run may not be required on the
downstream side of the flowmeter. However,
if a downstream valve or other fitting causes
irregularity or deviation in flows, provide a
straight run of 2D to 3D on the downstream
side.
*3: Highly recommend to mount valves on the
downstream side so that deviated flows do not
occur in the flowtube and to avoid startup from
an empty condition.
(4) Maintaining Stable Fluid Conductivity
IMPORTANT
Do not install the flowmeter where fluid
conductivity tends to become uneven. If
chemicals are fed near the upstream side of a
magnetic flowmeter, they may affect the flow
rate’s indications. To avoid this situation, it is
recommended that the chemical feed ports be
located on the downstream side of the flowmeter.
If it is unavoidable that chemicals must be fed on
the upstream side, provide a sufficient length of
straight run (approximately 50D) to ensure the
proper mixture of fluids.
F0302.EPS
(Incorrect)
Upstream side
(Correct)
Downstream side
Figure 3.1.2 Chemical Injection