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Installation errors
Replace safety valve.
Strictly follow manufacturer's instructions
and the requirements of the relevant
provisions in terms of requirements for
installation of safety valves – do not
induce stress during installation.
Forces like bending, or torque act on
safety valve.
Replace safety valve.
When designing the installation check the
manufacturer's instructions and the
requirements of the relevant provisions of
supervision institutions in the requirements
for pipes connected to the safety valve,
taking into account all the possible reaction
forces occurring at the outlet, provide for
appropriate support, do not let the valve to
be a supporting structure for the other
elements of the installation. Consider the
possibility to use safety valves with support
lugs.
Vibrations
Too high flow resistance in the supply
line - pressure loss in the supply line
exceeds 3% (set pressure of safety
valve)
Reduce flow resistance in the supply line.
If this is not possible, for some reasons -
consider the possibility of a safety valve
with damper. Effectiveness of this valve
construction is possible in particular
conditions – clarify with the manufacturer.
Wrong characteristic of the safety valve
in the protected installation
Analyse this matter, taking into
consideration special conditions. If such
adjustment is not possible- replace the
valve with a new one with a proper
characteristics.
The valve was designed with too large
capacity in relation to the requirements
of protected installation.
Analyse the selection of safety valve –
apply smaller valve, respectively to the
required capacity.
Built-up backpressure occurring in the
discharge line at the blow out from the
valve - exceeds the value allowed by
the manufacturer (10 ÷ 15% of the set
pressure) -e.g. too long outlet pipe, its
diameter is too small, rapid changes in
the direction of flow, the use of
silencers, etc.
If it is not possible to introduce changes to
the construction of discharge line,
reducing built-up backpressure - apply
valve with bellow compensation
Excessive fluctuation of the
superimposed backpressure at the
outlet of the valve (in the case of the
conventional valve i.e. unbalanced)
Apply valve with bellow resistant to
influence of changing superimposed
backpressure.
Too large construction lift of closing
element
(e.g. in case of full stroke safety valves
used for fluids)
Apply safety valve of characteristics
adjusted to this type of fluids, or- if the
manufacturer enables such construction-
reduce the construction lift of the full lift
valve to the value indicted by the
manufacturer.
Incorrectly made welds on connecting
pipes, too small gaskets on inlet and
outlet or gaskets placed incorrectly
(non-centrally) disrupting the flow
Eliminate incorrectness