Regulator Start-Up; Maintenance - Dresser Rb 4000 Betriebsanleitung

Regulator Start-up

After the pressure regulator has been installed, make sure
that the on/off valve upstream and downstream and the
vent valve are all closed .
• Partially open the upstream on/off valve slowly enough
to pass a very small amount of gas;
• Reset the safety shutoff valve (see the relevant Instruc-
tion Manual) . Note that a safety shutoff valve with over
and under- pressure protection is always closed in
absence of gas downstream from the regulator, where
its sensing line is connected .
• Check that the pressure rises slowly; the downstream
pressure must stabilize around the set value . If the pres-
sure continues to rise, interrupt the starting procedure
by closing the upstream on/off valve and identify the
cause of the malfunction;
• After the outlet pressure has stabilized, open the on/off
valve completely;
• Then slowly open the downstream on/off valve until
the piping is completely filled .
At this point, the pressure regulator is operative .
Monitor Start-up
The same procedure must be followed when starting a
monitor and active system, bearing in mind that the pres-
sure gauge installed in the section in between the two
regulators must indicate the same pressure value as the
upstream gauge .
Pressure Regulator Setting
The pressure regulator is usually delivered already set to
the specifications indicated in the order sheet . Whenever
the set pressure must be modified, this value must be set
within the setting range of the spring installed .
Make sure there is a flow demand or open the vent valve
downstream of the regulator . This valve should be closed
after the desired set pressure is obtained .
• To increase the set pressure: rotate the adjustment
screw clockwise using the adjustment wrench - see
Fig 8 .
• To decrease the set pressure: proceed as above, rotating
the spring adjustment screw counter-clockwise .
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Maintenance

The maintenance operations required for the pressure
regulator (and the safety shutoff valve) are closely linked
to the quality of gas supplied (in terms of moisture con-
tent, liquid hydrocarbons and impurities in general) and
to the degree of filtration performed upstream of the
pressure regulator .
For this reason we recommend always installing a car-
tridge filter upstream from the pressure regulator that
is capable of withholding the solid and liquid particles
present in the gas that might otherwise compromise ef-
ficient operation .
All pressure must be discharged before performing any
maintenance operation on the pressure regulator by
proceeding as follows:
• Close the on/off valves upstream and downstream,
• Slowly discharge the pressure by opening the vent valve
downstream from the pressure regulator until the gauge
indicates zero .
Before performing any maintenance operation on pres-
sure regulators fitted with overpressure and under
pressure shutoff devices, open the bypass between the
inlet and outlet chambers (see Instruction Manuals for
safety shutoff valve) . This relieves the pressure that other-
wise would be trapped upstream from the valve disc of
the safety shutoff device .
Disassembly
Check the following before beginning any disassembly
operations on the pressure regulator:
• The regulator must be depressurized as described above;
• The wrenches and other tools required for the operation
must be close at hand;
• Spare parts to replace damaged parts must be immedi-
ately available .
Remember to:
• Disassemble the actuator top casing only after removing
the loading spring;
• Disassemble all parts carefully in order to avoid dam-
age . Pay extra attention to the rubber parts (using the
appropriate tool for the disassembly of the O-rings) and
replace all parts that exhibit even the slightest signs of
damage .