Performance Testing of Lubricant Filter Elements Utilized in Aircraft Power and Propulsion Lubrication Systems
This SAE Aerospace Information Report (AIR) reviews performance testing parameters for non-cleanable (often referred to as disposable) filter elements utilized in aircraft power and propulsion lubrication systems, including gas turbine engines and auxiliary power units (APUs), propulsion and transmission gear boxes, and constant speed drives and integrated drive generators (IDGs).
This document is confined to laboratory testing of filter element performance to qualify the filtration medium and filter element construction as opposed to qualification of the complete filter assembly. The testing discussed here is usually followed by laboratory and on-engine testing of the entire lube filter assembly (including filter element, housing, valving, etc.), which is outside the scope of this AIR.
The proper specification of filtration in aircraft power and propulsion lubrication systems is important in protecting lubrication systems from particulate contamination that could lead to accelerated component wear, system malfunction, and premature component failure. This SAE Aerospace Information Report (AIR) provides information about standard test procedures developed for the evaluation of the performance of lubricant filter elements utilized in aircraft power and propulsion systems. This will allow both manufacturer and customer a common means to specify, control, and evaluate lubricant filter elements to ensure that the filter elements retain their functional characteristics under operating conditions.
The document has been revised to: (1) add the reference for the standard reference material (SRM 2806) used for calibration of automatic particle counters per ISO 11171 and include an update on the current status of the same; (2) move the ranking of the filter elements in Table 3, based on their Bubble Points, to be consistent with the required sequence of tests, and to include a Bubble Point test subsequent to flow fatigue conditioning; (3) add a statement to the end load test to allow for performing the test after cold start conditioning and subsequent Bubble Point determination if significant tensile forces may be experienced at the filter element end caps; (4) link the system(pump) relief valve pressure to the collapse rating differential pressure and delete the statement that the filter element can experience the collapse rating differential pressure under normal conditions since this is unlikely; (5) interchange the gravimetric efficiencies for Media A and B in Figure 3 that were incorrectly reversed; and (6) include numerous editorial changes for clarity.