Yokogawa ADMAG CA - Manual (Page 74)

IM 1E8B0-01E
9-4
9. MAINTENANCE
9.3.2 Unstable Zero
NO
Examine whether or not the
meter tube is filled with liquid
and the liquid does not contain
bubbles.
Examine whether or not the
valves leak.
Recheck liquid property.
Replace valves.
Sufficiency shield the meter.
Locate the meter as far as
possible from this equipment.
NO
NO
NO
YES
NO
NO
NO
YES
YES
YES
YES
YES
YES
It is convenient to provide a gas
vent hole on the downstream
side of the meter to check for
bubbles.
In particular, be careful for
horizontal meter mouting,.
Change mounting position or
change to vertical mounting
with upward flow so that the
tube is completely filled with
liquid.
Mount a deforming device on
the upstream side of the meter
· Confirm the meter grounding.
· Confirm whether or not the
grounding wire is
disconnected from the earth
flange.
a, Insure that the liquid
conductivity does not change
beyond fluid limits.
b, Do not use the meter with
liquid conductivity below the
specified value.
c, Decrease flow velocity near
the conductivity low limit as
much as passble.
• Remove dirt and scale on
and near electrodes.
• Change to vertical meter
mounting.
• Change the measuring mode
to the standard mode.
START
Are bubbles contained in the
liquid?
Is the meter tube filled with
liquid completely?
Are valves leaking?
• Does the fluid
conductivity vary or is
it easy to change?
• Is Liquid conductivity
sometimes below the
specified value?
Is the liquid likely to cause
deposit?
Is the flowmeter located
near mortors, transformers, or
other electric equipment?
*
*
Is grounding complete?
Insulation deterioration is suspected.
Examine the meter.
Grounding resistance must be
100
Ω or less.