Why is new oil filtered during the filling process?

Filling a machine with an oil that has a very low pollution class involves significant investments in order to ensure that this property is maintained right up until it enters the inside of the hydraulic circuit, without absolute guarantees in terms of the results.

Here are 4 critical phases during which there are risks of an oil being polluted, meaning that particular caution is required:

• The oil may be polluted during production at the factory. Producing a very clean oil involves additional processing in additional industrial machines.
• The packaging (drum, for example) used to transport the oil is exposed to stresses and so ages over time. Polluting particles can enter the oil. For this reason, oil that is delivered in bulk is cleaner than oil that is packaged in drums – there is no opportunity for pollution from the drum to get into the oil.
• Drums "breathe". As the temperature varies, exchanges between the exterior and the inside of the drum take place, allowing air containing pollutants to enter.
• There is another risk of the oil being polluted when it comes into contact with air or unprotected decanting components as it is transferred from its packaging into the circuit. 

 It is therefore far more profitable and efficient to filter the oil as it is brought into service or alongside the circuit, while the machine is in operation.
Furthermore, it is the only way of making sure that the level of cleanliness required by the equipment is obtained.