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Use a safety relief valve
Checking the oil level
Avoid particles
Setting the relief valve
Only with a heating cartridge: check the
action of the heating cartridge
Only at low temperatures: allow the pump
to warm up
Earthing lines
Potential equalisation lines (mandatory
with ATEX)
8.1 Bleeding the liquid end
CAUTION!
Danger due to incorrect use of the safety relief valve
The safety relief valve can only protect the motor and the
gear, only against illegal positive pressure that is moni‐
tored by the metering pump itself. It cannot protect the
system against positive pressure.
–
Protect the motor and gear of the system against
positive pressure using other mechanisms.
–
Protect the system against illegal positive pressure
using other mechanisms.
The actual opening pressure is above the nominal pressure (the pressure
stage) - refer to the "Technical data" chapter.
When the pump is idle, check whether the oil level in the pump is in the
middle of the oil level indicator.
This will rule out the pump losing oil and suffering damage.
For chemicals with a particle size greater than 0.3 mm,
the valves may no longer close properly.
–
Install a suitable filter in the suction line.
Only in areas at risk from explosion: Set the opening pressure of the relief
valve at a maximum of no more than 1.5 times the rated pump pressure .
Check the heating action of the heating cartridge and the effectiveness of
the protective temperature limiter. No overheating must occur, especially
in the area at risk from explosion!
1.
Switch on the heating cartridge, set the stroke length of the pump to
"0" and start the pump.
2.
Allow the pump to warm up for 5 minutes.
3.
Set the stroke length of the pump to the required value.
Check whether the earthing lines in the pump's electrical units are cor‐
rectly connected and connected to a clean earth wire - see earthing dia‐
grams in the appendix.
Check whether the potential equalisation lines are sitting correctly on the
pump and connected to a clean potential equalisation point.
When bleeding the liquid end or priming against pressure:
Depressurise the suction and discharge lines!
Start up and operation
51
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