SICK GM35

109
8009389/YN39/V3-0/2015-08| SICK OPERATING INSTRUCTIONS|GM35
Subject to change without notice
MAINTENANCE
9.4.5 Restarting and checking the purge air unit
1 Make sure that any dust possibly escaping from the open end of the purge air hose
when the purge air unit is switched on again cannot be deposited on the measuring
system:
– Align the open end of the purge air hose so that the air flow can escape unhindered
without creating dust clouds in the direction of the measuring system or measuring
probe.
– After the measuring probe has been taken out of the duct, cover the purge air inlet on
the measuring probe temporarily to protect it from dust.
2 Switch the power supply to the purge air unit on and let it run briefly (approx. 2 min.) to
remove any loose dust. The purge air hose is not yet connected to the measuring probe.
When connecting, knock the filter housing lightly to remove any dust particles.
3 While the purge air unit is switched on, reconnect the purge air hose to the purge air
inlet on the measuring probe or optional pressure difference sensor. Make sure the
hose clamp is secure.
4 With the purge air unit switched on, check whether
– a uniform air current is created at the open end of the measuring probe
– the blower is operating quietly, without any noticeable vibrations or irregular noises.
5 Test whether the low-pressure monitor to monitor the filter and the connected signal unit
are functioning correctly:
▸ Instruct the control room personnel, where the filter monitor signals are received, to
monitor the signals.
▸ Partly cover the extraction aperture of the air filter briefly using a piece of cardboard
or similar object (must not be sucked in or contaminate the filter).
▸ Check whether the low-pressure monitor responds by signaling that a filter change is
necessary.
9.5 Resuming Measuring mode
9.5.1 Inserting in the sample gas duct
1 Make sure the SR-unit is securely mounted on the flange fixture, and therefore on the
measuring probe, with the four quick-release fasteners.
2 If a purge air supply is used, make sure it is in operation and remains switched on from
this point onwards.
If the angle flange, Part No. 2 017 833, is used:
3 Remove the measuring probe with mounted SR-unit from the angle flange.
4 Disassemble the angle flange from the duct-side flange with tube.
If an angle flange is not used:
1 Remove the protective cover, when fitted, from the duct-side flange with tube.
2 Insert the measuring probe with mounted SR-unit in the duct-side flange with tube.
3 As shown in
“Removing the measuring probe with attached SR-unit from the duct-side
flange”, page 103, mount the measuring probe on the duct-side flange using the parts
(4 screws M16x60, each with nut and 2 washers) removed earlier.
4 When using a GPP measuring probe, it is important to restore the power supply quickly
(see “Electrical connection”, page 110) so that the optical interfaces in the measuring
probe are heated again as fast as possible.
WARNING: Hazard through hot, aggressive or pressurized sample gases
When carrying out the activities below, observe the safety instructions on
page 99 at all times to prevent any hazards to health.