Abstract: An apparatus and procedure is provided for testing and evaluating the sealing effectiveness of dynamic seals of the type having at least one and often at least two dust-excluding seals. Included is a housing having a support wall formed with an opening through which a representative shaft is supported for rotation. An annular gap exists between the shaft and wall opening and is closed by the test seal. A dust chamber is provided on the atmosphere side of the test seal and includes a slow speed dust redistribution device which gathers and transports dust from the bottom of the chamber to the top where it is released and falls back into the chamber. A high speed beater agitation device disperses the released dust to maintain a constant density dust cloud environment within the dust chamber. A dry dust collection chamber is provided on the opposite oil side of the test seal.

Abstract: A shaft seal assembly includes an outer stationary carrier, an inner member, and a sealing system including a primary lubricant-retention seal that is fixed to the carrier in combination with a number of debris-excluding seal features. Such features include a first debris-exclusion seal fixed to the carrier adjacent the primary seal and a second debris-exclusion seal that is mounted on either the carrier or inner member and has at least one lip sealingly engaging the other of the carrier and inner member in spaced relation to the first debris-exclusion lip defining a sealed annular cavity therebetween. Disposed within the cavity is a porous filter element in the preferred form of an open cell sponge. The various dust exclusion features cooperate to allow each to perform efficiently. The outermost second debris-exclusion seal guards the foam against substantial debris, and the foam in turn protects the first debris-exclusion lip against virtually all debris.