B-320-2-E
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(3) Liquids of low steam pressure
Temperature and pressure of LPG, polyvinyl
chloride monomers or anything with low
viscosity and low steam pressure that are prone
to vaporize should strictly be controlled.
During operation, the temperature of bearings
in the meter is usually higher than that of the
metered fluid. Vapors around the bearings
can be causes of faulty conditions, including
generation of unusual noise and bearing burn.
(4) Corrosive liquids
When you make a measurement of highly
corrosive liquids, such as nitric acid and sulfuric
acid, appropriate materials should be used for
tanks and piping assembly. Heterogeneous
materials originally contained in the metered fluid
or corrosive substances dissolved from tanks
and pipes of inappropriate materials may lead
to costly downtime, as a result of locked rotors,
for example, when they are allowed into the
measuring chamber.
TAKE PRECAUTIONS
AGAINST
BEARING BURNING!
Fig. 8.3
CAUTION
8.5 Precautions at Operation Shutdown
(1) Valves should be closed progressively.
Rapid valve closure could, under certain piping conditions, cause a sharp pressure rise by water hammer,
or hydraulic shock, resulting in damage to the meter.
(2) Precautions against pressure buildup on closure
Complete closure of valves upstream and downstream of the meter makes the affected section a totally
enclosed chamber and a pressure buildup inside due to the rise of atmospheric temperature could lead to
an unexpected damage to the meter.
(3) Liquids ready to adhere or gel at zero flow velocity
Liquids that tend to adhere and solidify or gel at flow velocities around zero must thoroughly be washed
away from the meter interior with running cleaning fluid before shutdown. Negligence of this instruction
may leave the meter as an immovable unit when the operator attempts to resume meter operation the next
time.
8.6 Strainer Inspection
The strainer net should be inspected for condition and cleaned on a regular basis.
In a newly installed piping system, in particular, inspect daily first and, according to the degree of clogging of
the net observed, the time interval for inspection may be reduced progressively to, say, once a week.
