Solid oil is a solid choice

Citation

(2001), "Solid oil is a solid choice", Industrial Lubrication and Tribology, Vol. 53 No. 1. https://doi.org/10.1108/ilt.2001.01853aad.004

Solid oil is a solid choice

Solid oil is a solid choice

Keywords: Oils, Bearings, Lubrication

A technology that has been available for many years, but remains largely misunderstood, according to SKF, is the use of solid oil for bearing lubrication.

Essentially, solid oil is the description of a material whereby the oil is retained within a polymer matrix. Its use is appropriate for most applications where conventional oils or greases are unsuitable.

Typical of such applications are a number in the paper industry where the lubricant has several advantages including resistance against impurities and an inherently high chemical stability. In low temperature applications, the fact that solid oil does not increase in viscosity, as does conventional grease, means that starting torque is not increased with dropping temperatures. The inert nature of solid oil, its resistance to aggressive agents and its ability to deliver maintenance free operation, also makes the lubricant suited to cranes, chemical mixers, electronics manufacturing, food processing, printing presses and pumps (see Plate 4).

Solid oil works by completely filling the internal space in the bearing – effectively encapsulating the cage and the rolling elements. Indeed, the cage provides a reinforcing element for the oil and rotates with it. By releasing the oil from the polymer during operation, both the rolling elements and the raceway are lubricated efficiently. Moreover, the viscosity of the oil will also decrease with increasing temperature. When the bearing stops running, excess oil is re-absorbed by the polymer matrix. The technology of the polymer is such that millions of micropores hold the oil within the material by surface tension alone. The oil represents about 70 per cent by weight of the material. Bearings filled with solid oil contain between twice and four times as much lubricant as a greased bearing. This is because, typically, only one-third of the internal space is filled by the grease.

Plate 4 A technology that has been available for many years, but remains largely misunderstood, according to SKF, is the use of solid oil for bearing lubrication

Most normal sizes of SKF ball and roller bearings can be supplied with solid oil, although certain large volume polyamide or brass cages are less suited because of speed constraints imposed by the technology. SKF bearings with solid oil lubricant are identified by a suffix W64.

For further information contact: Jerry Truman or Phil Burge, SKF (UK) Ltd, Sundon Park Road, Luton, Beds LU3 3BL, UK. Tel: + 44 (0)1582 490049; Fax: +44 (0)1582 848091; e-mail: jerry.truman@skf.com