Alternative Fluids

See also the General Information in the SAI catalogues

It is always preferable to use Mineral Oil to ISO standards to obtain the published performance and normal lifetime of SAI Hydraulic Motors.

SAI are not able to comment with any certainty on the suitability of the many Biodegradable or Synthetic Fluids currently on the market, or from any specific Manufacturer, other than to say that they SHOULD be OK!

The manufacturers of such fluids produce data sheets invariably claiming that their fluid is equivalent in performance to standard mineral hydraulic oils, if true, there would be no problem, and there are many applications running successfully on these fluids.

It is for the Customer to satisfy himself by contacting the Fluid Supplier to confirm whether special seals are required for the fluid in question and to establish the comparative lubricity UNDER LOAD of such fluids when compared with standard mineral hydraulic oils.

Without doubt, SAI motors will perform on ANY fluid, including WATER, but the projected
lifetime of bearings and the effect on sealing components (nitrile rubber is known to swell with phosphate ester fluid) and leakage (efficiency) is something which should be considered.

Viton Seals are available (extra cost) for all SAI products where, for example, a Phosphate Ester fluid is to be used

As a GENERAL comment, SAI (GB) Limited would advise that Motors running on fluids other than “normal” mineral oil should be sized conservatively so as to be running well within their overall pressure and speed ratings.

The Customer is encouraged to consider whether the use of Biodegradable or Synthetic Fluids is really necessary as “normal” hydraulic fluids are, to a large degree, biodegradable!!

Also, cost could be another consideration as, not only are these fluids very expensive, but the recommendation is often that the fluid is changed much more regularly than would be required with Mineral Oil.

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