Importance

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Abstract

Apparatus 10 (FIG. 1), for testing samples of friction material 31, 32 in rubbing contact with a surface 33 of a rubbing element 34, comprises a table 12 for supporting the rubbing element and a load cell 16 for sensing the load imposed by the frictionally coupled rotating samples from which the coefficient of friction can be determined. To make the tests repeatable rapidly and with identical starting conditions cooling means 40 is interposed between the rubbing element and table. Cooling means 40 comprises a fluid cooled heat exchanger 41, conveniently cooled by local main supply water supplied at its natural temperature, and thermoelectric cooling means 75. The thermoelectric cooling means consists of an array of planar peltier cooling elements which develops a temperature gradient there across which, with reference to the heat exchanger temperature, is able to cool and re-cool the rubbing element to temperatures as low as -25.degree. C. within a matter of minutes. To ensure the friction material and rubbing element are not contaminated by water condensed from the atmosphere an enclosure 60 is formed around them and kept at positive pressure by dry, inert argon gas.

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First Claim