Drainage; Operating Pressure And Set Pressure; Ambient Conditions; Protective Coating - Leser 4401 Instrucciones De Servicio

Operating Instructions

4.2 Drainage

As a rule, safety valves are delivered
without a drainage opening because the
drainage must take place via a blow-off
line. Only in exceptional cases are drain-
age openings permitted or even required
directly in the safety valve (e.g. for instal-
lation on ships).
Safety valves can be ordered with a drain-
age opening. Even afterwards, a drainage
opening can be drilled at the spot desig-
nated for it. The respective drawings must
be requested from the manufacturer.
Drainage openings that have no function
must be sealed.
4.3 Operating Pressure and
Set Pressure
In order to guarantee reliable closing after
a safety valve opens, system operating
pressure must continuously remain below
the set pressure.
The operating pressure must be at least
the value of the closing pressure difference
plus 5% below the set pressure.
The clamping force of a spring-loaded safe-
ty valve drops as the operating pressure in-
creases. The closer the operating pressure
is to the set pressure, the more likely it is
for the medium to escape (only A).
This may result in leaks especially if the
sealing surfaces are damaged or dirty.
If the compressed air for the supplementa-
ry loading fails, then the safety valve func-
tions just like a conventional safety valve
without supplementary loading (only C).

4.4 Ambient Conditions

The controllers
designed for use between 2 °C and 60 °C.
Safety valves made of stainless steel are
recommended for use under extreme con-
ditions.
The safety valves and pipelines must be
protected from atmospheric influences.

4.5 Protective Coating

Safety valves are given a protective coat-
ing at the factory. The protective coating
protects the safety valve during storage
and transport. If the external conditions are
corrosive, then additional corrosion protec-
tion is necessary.
Moving and functionally important parts
must not be given a protective coating.
and actuators are
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EN