Circulating Oils

Circulating oils: not the same as hydraulic oils

A circulating oil serves bearings, vacuum pumps and gear sets where there is no anti-wear requirement from a high-pressure pump. What matters instead is oxidation stability at temperature, rust protection, air release and above all demulsibility — the ability to shed water so it can be drained from the bottom of the reservoir rather than circulating as an emulsion.

• LEDA CR (ISO VG 100, 150, 220, 320, 460) — bearing and circulating oil with anti-rust and anti-foam additives and excellent demulsibility, for bearings, vacuum pumps and industrial gears requiring high thermal stability.
• LEDA M CR (ISO VG 220, 320, 460) — formulated for MORGOIL circulation systems on paraffinic base oils with zinc-free anti-wear additives, with oxidative stability, strong water and air separation and rust protection. Rolling mill bearing systems specify this rather than a general circulating oil, and the specification is not interchangeable.

Choosing the grade

Follow the machine builder. Broadly, lighter grades suit higher-speed bearings and systems with effective cooling, heavier grades suit slower, more heavily loaded bearings and combined gear duty. Where oil runs persistently hot — the normal case in an Iraqi plant without conditioned air — the higher grade within the permitted range is usually safer.

Water is the thing to watch

Circulating systems accumulate water from cooler leaks, steam and washdown. That is why demulsibility is specified, and why the reservoir should be drained from the low point on a routine rather than when someone notices a problem. Cloudy oil is water, and water in a bearing circuit does its damage long before it announces itself. For pressurised hydraulic systems with anti-wear requirements, see the hydraulic oil guidance instead.

Frequently asked questions

Not sure which product a vehicle, machine or fleet needs? Try the Cyclon oil selector, or send us the details and we will specify it in writing.