Internal seal of packing gland assembly is worn.
Replace packing gland and O-ring seal.
OPERATING NOTES:
·
Two common causes of packing gland leakage
are thermal expansion and hydraulic shock.
·
Thermal expansion can occur when two valves in
a piping system, on either side of the meter, are
closed at the same time and the temperature in
the system rises. As little as a 1°F increase in
temperature can drive the system pressure to a
point that exceeds
·
the maxiumum working pressure rating of the
meter. To avoid any damage caused by thermal
expansion, a pressure-relief valve of some kind
must be installed in the system.
·
Hydraulic shock occurs when a large volume
(mass) of liquid is flowing through the system
and a valve suddenly closes. When the flow is
stopped, the entire mass of the liquid in the
piping system rams into the components within
the meter. The greater the length of line (more
line length equals more liquid mass) and the
greater the velocity of the liquid, the greater the
hydraulic shock. Since the valve is usually
located at the meter outlet, the meter housing,
packing gland and the meter internal are subject
to the full impact of such hydraulic shock. To
prevent hydraulic shock, a slow closing two-
stage valve should be used with the meter. On
systems where mass length of line and velocity
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