Hydraulic fluids for PVG
Oils
The main duty of the oil in a hydraulic system is to transfer energy; but it must also lubricate the moving
parts in hydraulic components, protect them against corrosion, and transport dirt particles and heat out
of the system. It is therefore important to choose the correct oil with the correct additives. This gives
problem-free operation and long working life.
Mineral oils
Danfoss Power Solutions recommends for systems with PVG 120 valves to use mineral-based hydraulic
oils containing additives: Type H-LP (DIN 51524) or HM (ISO 6743/4).
Non-flammable fluids
Phosphate-esters (HFDR fluids) can be used without special precautions. However, dynamic seals must be
replaced with FPM (Viton) seals. Please contact the Danfoss Power Solutions Sales Organisation if the PVG
120 valve is to be used with phosphate-esters.
The following fluids should only be used according to agreement with the Danfoss Power Solutions Sales
Organisation:
•
Water-glycol mixtures (HFC fluids)
•
Water-oil emulsions (HFB fluids)
•
Oil-water emulsions (HFAE fluids)
Biodegradable fluids
PVG 120 valves can be used in systems using rape-seed oil. The use of rape-seed oil is conditional on:
•
it complying with the demands on viscosity, temperature and filtration, etc.
•
the operating conditions being adapted to the recommendations of the oil supplier.
Before using other biodegradable fluids, please consult the Danfoss Power Solutions Sales Organisation.
Particle Content, Degree of Contamination
Oil filtration must prevent the particle content from exceeding an acceptable level, i.e. an acceptable
degree of contamination.
Maximum contamination for PVG 120 is 23/19/16 (see ISO 4406).
Calibration in accordance with the ACFTD method.
In our experience a degree of contamination of 23/19/16 can be maintained by using a filter fineness as
described in the next section.
Filtering
Effective filtration is the most important precondition in ensuring that a hydraulic system performs
reliably and has a long working life. Filter manufacturers issue instructions and recommendations. It is
advisable to follow them.
System filters
Where demands for safety and reliability are very high a pressure filter with bypass and indicator is
recommended. Experience shows that a 10 µm nominal filter (or finer) or a 20 µm absolute filter (or finer)
is suitable.
It is our experience that a return filter is adequate in a purely mechanically operated valve system.
The fineness of a pressure filter must be selected as described by the filter manufacturer so that a particle
level of 23/19/16 is not exceeded. See
Particle content, degree of contamination
for more information.
Technical Information
PVG 120 Proportional Valve Group
Other operating conditions
520L0356 • Rev JA • Mar 2014
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