nord B 1050, Operating And Assembly Instructions Manual

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Industrial gear units – Operating and Assembly Instructions
108 B 1050 en-4419
7.7 Leakage and leak-tightness
Gear units are filled with oil or grease to lubricate the moving parts. Seals prevent the escape of
lubricants. A complete seal is technically not possible, as a certain film of moisture, for example on the
radial shaft sealing rings is normal and advantageous for a long-term seal. In the region of vents,
moisture due to oil may be visible due to the escape of oil mist because of the function. In the case of
grease-lubricated labyrinth seals, e.g. Taconite sealing systems, used grease emerges from the
sealing gap due to the principle of operation. This apparent leak is not a fault.
According to the test conditions as per DIN 3761, the leak is determined by the medium which is to be
sealed, which in test bench tests exceeds the function-related moisture in a defined test period and
which results in dripping of the medium which is to be sealed. The measured quantity which is then
collected is designated as leakage.
Definition of leakage according to DIN 3761 and its appropriate use
Location of leak
Term Explanation
Radial shaft
seal
In IEC adapter Housing joint Venting
Sealed
No moisture
apparent
No reason for
complaint
No reason for
complaint
No reason for
complaint
No reason for
complaint
Damp
Moisture film locally
restricted (not an
area)
No reason for
complaint
No reason for
complaint
No reason for
complaint
No reason for
complaint
Wet
Moisture film beyond
the extent of the
component
No reason for
complaint
No reason for
complaint
Repair if
necessary
No reason for
complaint
Measurable
leakage
Recognisable
stream, dripping
Repair
recommended
Repair
recommended
Repair
recommended
Repair
recommended
Temporary
leakage
Temporary
malfunction of the
sealing system or oil
leak due to
transport *)
No reason for
complaint
No reason for
complaint
Repair if
necessary
No reason for
complaint
Apparent
leakage
Apparent leakage,
e.g. due to soiling,
sealing systems
which can be re-
lubricated
No reason for
complaint
No reason for
complaint
No reason for
complaint
No reason for
complaint
Table 23: Definition of leaks according to DIN 3761
*) Previous experience has shown that moist or wet radial shaft sealing rings stop leaking later.
Therefore, under no circumstances can replacement be recommended at this stage. The reason for
momentary moisture may be e.g. small particles under the sealing lip.
7.8 Noise emissions
The
measuring surface sound level
to be expected for the gear units according to ISO 8579-1 is below
the 50% line stated in the standard.