dear sir,
we have been using a phosphate ester based hydraulic oil in a powerpack and have found that the oil changes color very fast ( black). the vane pump failed and the following hydraulic problems occured .
1)DC VALVE STUCK AND CRANE ROOF NOT LIFTING
2)VANE PUMPS NOT DEVELOPING ENOUGH PRESSURE
3)DC VALVE SPOOL STUCK
There was a reddish brown coating on the pump components which we analysed and found that the coating consists of potassium , sodium ,sulpur and chloride compounds .
the phosphate ester used contains chlorinated paraffin ( ISO CLASSIFICATION HFD-S)but we could not explain the reason for the other elements . We also checked the oil and found that the TAN number has increase from 0.3 to 0.55 and the oil also contains the same contaminants . pl let us know the reason and the remdial measures to be taken to solve these problems
e