Transmission filter felt

摘要

A transmission fluid filter material and transmission filter produced therefrom comprising a gradient density composite felt which exhibits high particle removal efficiency at 40 micron diameter particle size and larger with exceptionally high dirt holding capacity and no significant increase in clean pressure drop. The upstream portion of the composite felt contains fine fibers that selectively remove first the fine particles while the downstream portion acts to sieve coarse particles and build a porous filter cake, thereby extending the useful life of the filter.