Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1412702
8 | September - October 2021 | www . machinerylubrication.com distribution of particles (e.g., ISO Medium Test Dust) to the filter test loops during the test cycle. Filter testing can take several hours from start to completion. Together, the filter test loops can handle flows ranging from 0.26 gpm to 106 gpm (1 L/min to 401 L/min). To start a test, the filter is mounted above the shallow rectangular sink on the left using the hardware corresponding to the required flow rate. In Figure 4, a small spin-on filter is shown mounted to the low-flow rate test loop. e high-flow test loop is positioned above. e lower left hardware shows a flat-sheet holder for testing swatches of filter media in the same way a cartridge or spin-on filter might be tested. Flat-sheet testing evaluates the performance of the media only, not the entire filter element collectively. Before each test, the filter flow rate and terminal pressure drop are entered manually at the computer control station. Most other operating conditions, including contamina- tion injection rate, temperature, dilution ratio, etc., are predetermined by the standard and operating system. Other test protocols would be required for cyclic flow testing (ISO 23369). Multipass testing enables filters to be tested to an international standardized protocol. is enables published data to be compared apples- to-apples to other candidate filters tested using the exact same protocol. It also removes subjec- tivity and differences in data interpretation. For instance, what do you understand when a filter is represented as being 10 microns nominal? How about 10 microns absolute? Or Beta (10) of 10? Multipass testing is a consensus standard written by industry peers. As such, it removes COVER STORY Figure 6. Data from a multipass test report. The table at the top shows dirt-holding capacity and particles sizes corresponding to filtration ratios at 2, 10, 75, 100, 200 and 1000. The plot shows how filtration ratios change dynamically over time as particles become more heavily retained by the filter. Figure 4. The left-side test sink shows a small spin-on filter mounted and ready for testing. Figure 5. Filter tests conditions are defined at the computer station before the start of the test. This is followed by a warm-up stage. During the test, data appears on the screen circuit diagram.