Cod. 985719 – 00 / July 2004
15
5.1.1. ATEX version
Carry out, every month, the following operations:
• for category 2D and 3D fans, remove dust on all the components if the film is thicker than 2mm
• protect the bearings so that dust cannot contaminate the grease
• make sure that bearings temperature is not higher than the maximum surface temperature of the class listed in the
rating plate
5.1.2. Drive
We recommend to check the drive system at least every three months.
In particular:
• check belt tension and their integrity; in case of damage, replace the belts
• make sure that pulley grooves are clean
• check pulleys alignment
5.1.3. Bearings
Every maintenance operation must be carried out with suitable tools.
A first check of the bearing can be done simply by listening to it. A normal bearing generates a smooth and uniform
sound; while a damaged bearing generates a loud and irregular sound.
A low metallic noise, due to standard gap between the components, is normal, especially at low speed.
Excessive vibrations or temperature are often a sign of possible damages.
Check periodically seals integrity and the bearing locking system.
Make sure that there is not excessive leak of grease from the bearing. A leak of a little quantity of grease is normal,
expecially in the first working hours.
The bearings mounted on Nicotra fans are estimated to have a mechanical life (L
10h
) of 40,000 working hours when
selected within the operating limits and standard conditions mentioned in the catalogue or with an appropriately sized
drive.
The actual life of the grease contained inside the bearings may be shorter than the mechanical life of the bearing itself.
Bearings mounted with rubber shock absorbers or inside plummer blocks without grease nipples, are lubricated for life.
Bearings with re-lubricatable plummer blocks should be used for heavy duty applications. Periodical re-lubrication is
necessary to achieve the full mechanical life of bearings.
5.1.4. Bearings lubrication
Many factors can determine when re-lubrication of the bearings is required: the type and dimension of bearing, its
operating speed, the working temperature, pulleys dimension, installed motor power, type of grease and the working
environment. It is therefore only possible to give some indications based on statistical data available.
For these reasons the re-lubrication intervals t
f
( time period, at the end of which 99% of the bearings are still reliably
lubricated, and represent L
1
grease lives. The L
10
grease lives are approximately 2,7 the L
1
lives) can be obtained from
the attached figure taking into account the rotational speed and diameter. This figure is valid for bearings on horizontal
shafts with normal loads and for temperatures not higher than 70°C. For higher temperatures we suggest halving the
time between re-lubrication every 15°C increase in ambient temperature, without exceeding the maximum working
temperature stated in the catalogue.
To Next Page
Loading...
Need help?
General
