High-speed, rotating metal parts have created lubrication, and consequently wear, problems for many years for the reason that they must be housed in metal bearings having a different coefficient of expansion. As a direct result thereof, the high speeds of rotation generate heat despite adequate lubrication between the parts, with the result that the opposed metal parts expand at a different rate, which permits the lubrication to escape from the gear box in which it is contained. Once the lubrication escapes, substantial wear is experienced and the installation is doomed if the movement is continued. Similar problems are experienced with respect to installations utilizing high speed reciprocating movements.
Seals located between such metal parts in the form of bearings, for accommodating such high speed relative movement over prolonged periods, can be advantageously formed of recently developed materials which have a high degree of inherent lubrication. Thus, a bearing product sold under the trademark VESPEL, although very costly and one which must be machined, will function as a seal under such conditions, provided it is urged gently and firmly but continuously against the sealing surface without excessive pressure, the latter being a cause of undue wear. However, experience has shown that no construction heretofore conceived or known would adequately furnish such a seal because no way was known for providing such gentle pressure continuously and substantially uniformly between metal parts having standard variations in dimensions, and over all of the temperature ranges generated during long periods of high speed movements. No way was known for automatically adjusting such pressure to compensate for dimensional changes over the gamut of temperature variations created within such parts.