Yokogawa ADMAG AXW - Manual (Page 10)

<3. INSTALLATION>
3-1
IM 01E25D11-01EN
3. INSTALLATION
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.
3.1 Piping Design Precautions
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 (the lining). For
more information, refer to Chapter 6 “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, and other power
sources in order to avoid interference with
measurement.
(3) Required Lengths of Straight Runss
To maintain accurate measurement, see JIS B7554
“Electro Magnetic Flowmeters” which explains the
requirements for upstream piping conditions of
magnetic flowmeters.
Based on JIS B7554 “Electro Magnetic Flowmeters”
and our piping condition test data, we recommend
the piping conditions as shown in the following
figures.
When installing two or more magnetic flowmeters
on a single pipe, provide a run of at least 10D
between them.
F0301.ai
D: Flowtube Size
Gate valve
fully open
5D or more
2D
or more
Reducer
pipe
Expander
pipe
0 is allowable. 0 is allowable. 10D or more
10D or more
Tee
90-degree bent
Various valves
0 is allowable. 5D or more 0 is allowable. 5D or more
2D
or more
2D
or more
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: The valves shall be mounted 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.ai
(Incorrect)
Upstream side
(Correct)
Downstream side
Figure 3.1.2 Chemical Injection