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Pressure in installation still rising
despite open safety valve
Inadequate selection of the safety valve
– too small capacity of the valve in
relation to the installation
requirements
Reselect the valve considering the
required capacity and replace it with a
proper one.
Safety valve constantly releases
medium
Valve spring is broken – as a result of
corrosive medium or destroyed by a
different factor
Replace the spring or the entire safety
valve. In case of steam – consider the
possibility of applying valve with open
bonnet..
“hangs” of the valve (the valve opened
but did not close)
Diagnose the cause of the “hangs” If it is
not possible to eliminate the reason-
replace the valve.
Very large damage to the surface of
sealing, e.g. as the result of long-term
leakage, crack of seat, “pitting” due to
the medium
Replace the valve with a new one.
Pressure do not fall down to closing
pressure
Preserve adequate ratio between working
and closing pressure
Crew injuries at discharge
condition and external medium
leakage
Use of safety valve without external
tightness test confirmed by the
manufacturer
Use valve with gastight construction, that
is with external tightness test of the valve.
Use of valve in which sealing is not
adequate to the properties and
parameters of medium.
Replace sealing in the operating valve with
the adequate one (after consulting the
manufacturer) or
replace the entire valve.
Incorrect discharge of medium from the
safety valve
In case of steams and gases, the
discharging pipe should be directed
upwards, enabling safe discharge, minding
that outlet end connector cannot be
rigidly connected to the pipeline. In
addition, in each case, the safety valve
outlet flange (free discharge into the
environment) or drain line must be
positioned so that the flowing medium
does not pose a threat to the
environment. Follow the requirements of
supervising institutions regulations and
indications and recommendations of the
manufacturer.
Incorrect drainage medium form the
valve and form the discharge pipe.
Eliminate the incorrectness in the
drainage line, following the requirements
of supervising institutions regulations and
indications and recommendations of the
manufacturer.