Enviromentally acceptable lubricants
Dear Customer,
Enclosed, please find some general guide lines for change-over from current mineral oil to EAL.
Please note that the purpose of the guide lines is information only and LUKOIL Marine Lubricants is not liable for any errors. Therefore, an actual change-over should be done by shipowner’s decision according to Original Equipment Manufacturer (OEM)’s instruction.
General Information for Change-Over from Mineral Oil to EAL according to Theissen:
1. Drain warm hydraulic oil from the complete equipment, including reservoir, cylinders, cooler, pipelines. Keep in mind that the reservoir of common equipment contains only 60 to 70% of the total oil volume. The remainder is distributed throughout the whole equipment. The more thorough the draining results, the less flushing cycles are required. To check the flushing result, measure the amount of oil removed.
2. Check reservoir inside, clean if necessary. Check reservoir cap for clean condition and presence of the air filter.
3. Clean filters and replace filter cartridges.
4. Fill the system with EAL. If available, a special flushing fluid may be used here.
5. Release air and start equipment cautiously. Attention: cylinders with air pockets left inside operate differently than usual; the end damping feature may be temporarily out of order. All drives have to be moved several times in order to flush the whole system. Closed circuit hydrostatic drives, e.g. wheel drives of construction equipment, have to be flushed very thoroughly, because the fluid circulates several times before being replaced.
6. Check fluid level in the reservoir often. In case of sinking level – when air is being removed from the system – add oil to avoid suction of air or foam into the pump. Temporary foam generation during flushing is normal. Two reasons are responsible for this: Rests of air left in the system dissolve into the oil under high pressure, and are released subsequently when the oil returns into the reservoir with low pressure. Furthermore, the mixture EAL and mineral oil present during flushing has poor air removal and defoaming properties. With the final fill, and after a few hours of operation, foam generation should normalize at a lower level.
7. Drain system again as described above, refill with EAL and start-up. Move all drives again, repeat if necessary.
8. Flush fills are not suitable for unsupervised continuous operation of the equipment. Only after finishing the procedure may the equipment be released for continuous operation. The number of flushing cycles depends on how well the system can be drained. That means, it depends on the reservoir/system volume ratio, and if cylinders and pipelines have been drained completely. As an example, two limit cases are given: If the system is drained down to 14% every time, than twice draining, one flush fill and a final fill yields exactly 2% of remaining mineral oil, which is required in the industry standard ISO 15380 (14% of 14% is 2%). Should the draining only be possible down to 27%, draining is required three times, with two flush fills and one final fill, to achieve the 2% limit.
Maintenance issues:
Second filter cartridge replacement: After operating approximately 50 hours since the change, oil filters have to be checked for elevated amounts of debris, and replaced if necessary.
Cleanliness: EAL is sensitive to humidity, therefore its water content should not exceed 0,1%. If the oil is warmed up normally, a clean air filter installed, and the environment not too hot and wet, the oil in the reservoir will dry automatically during operation of the machine. However, extreme environmental conditions or inappropriate cleaning may cause major amounts of water to enter the system, that can only be removed with special filter cartridges. Good filtering or bypass micro-filtering will extend considerably the life expectation of the oil fill. This pays back quickly, especially when using expensive EAL.
Intermixtures: Mineral oil contamination may cause severe damage to the components. To avoid contamination with mineral oil during later operation, caused by ignorance when refilling leakage losses or changing oil, the equipment should be labelled clearly at the reservoir fill opening. For the same reason enough stock of replacement fluid should be available to refill leakages, otherwise there will always be a temptation to refill with easily available mineral oil.
Lab checks: It is good practice to take oil samples at regular intervals and have them checked in a laboratory for excess wear of the fluid or the hydraulic components. This pays back through longer usage already for mid-size equipment with 100 liters (25 gallons) oil volume or more, but it helps to support maintenance even for smaller machines. Normal recommendations are 500 hour intervals. This will provide regular information about the condition of the equipment. Furthermore, this allows replacing the oil when necessary, as late as possible, avoiding many expensive oil changes.
References
Dr.-Ing Heinrich Theissen, 2006. Work instructions “Changing Over to Bio-Oil”: Institut für Fluidtechnische Antriebe und Steuerungen