36
1. Fully open the shut-off element in the suction head/suction lift line.
2. Close or slightly open the shut-off element in the discharge line.
3. Start up the motor.
4. Immediately after the pump has reached full rotational speed, slowly open
the shut-off element in the discharge line and adjust it to comply with the duty point.
5. When the operating temperature has been reached and/or in the event of leakage, switch
off the pump set and re-tighten the bolts between lantern and casing.
6. Check the coupling alignment and re-align the coupling, if required.
6.1.11 Checking the shaft seal
The mechanical seal only leaks slightly or invisibly (as vapour) during operation. Mechanical
seals are maintenance-free.
The packed gland must leak slightly during operation.
Adjusting the leakage
1. Only lightly tighten the nuts of the stuffing box gland by hand.
2. Use a feeler gauge to verify that the stuffing box gland is mounted centred and at a right
angle to the shaft.
The gland must leak after the pump has been primed.
The leakage can be reduced.
1. Tighten the nuts of the stuffing box gland by 1/6 turn.
2. Monitor the leakage for another five minutes.
Excessive leakage:
Repeat steps 1 and 2 until the minimum value has been reached.
Not enough leakage:
Slightly loosen the nuts at the stuffing box gland.
No leakage:
Switch off the pump set immediately!
Loosen the stuffing box gland and repeat start-up.
DANG E R
Seal leakage at operating temperature
Hot or toxic fluid could escape!
After the operating temperature has been reached and/or in the event of
leakage, switch off the pump set and re-tighten the bolts between lantern and
casing.
Check the coupling alignment. Re-align the coupling if required.
Mechanical seal
Stuffing box packing
Pure graphite
packing ring
Prior to
commissioning
After five minutes
of operation
DANG E R
Impermissibly high temperatures at packed glands
Explosion hazard!
Always use suitable temperature monitoring for packed glands.
Pack glands properly.
If a pure graphite packing ring is used, some leakage is essential.
Table 15: Leakage rate of the pure graphite packing ring
Quantity
Values
Minimum
10 cm ³/min
Maximum
20 cm ³/min
6 Commissioning/Start-up/Shutdown
