Oil Filter Testing

Southwest Research Institute (SwRI) characterizes oil, fuel, and hydraulic filter performance and integrity using a computerized fluid filter bench test facility. Testing determines filtering ability according to the various engineering specifications as well as specialized requirements for lubricant oil, hydraulic, and fuel filters of all sizes, including automotive, light- and heavy-duty diesel, and locomotive filters.

The Institute's 1,500-square-foot facility features versatile, computer-controlled emulated test systems for both Class A and Class B operations. This setup allows the differential pressure buildup across the test filter to be measured as contaminants are removed. The system's automated contaminant-additions handler provides a variable contaminant add-rate for selected compositions. The computer controls and monitors the temperature, safety features, automated sampling, and inlet, outlet, and differential measurement.

Using an automatic sampling manifold, SwRI runs life and efficiency tests for oil filters. A computer controls the stand, setting conditions on a computer monitor and keyboard and automatically running the stand for 24 hours or longer, as required.

The Institute's oil filter test stand is computer-controlled to monitor its temperature, safety features, automated sampling, and inlet, outlet, and differential measurements systems.

Using computer data displays, operators monitor oil filter tests and make any necessary adjustments as the test progresses.

Virtual Instrument Concept

The filter test stand computer uses virtual instrument (VI) hardware control. The software technique replicates, on the computer, the appearance and function of the corresponding hardware. The operator trained to use the workbench apparatus can use the VI with no additional training. The VI display screen is familiar; an experienced operator will recognize all system controls. The computer-controlled systems provide preprogrammed test sequences to run, monitor, and terminate standard test formats automatically. Menu-driven programming allows operators to design and implement custom test parameters easily.

Precise Mass Flow

Combining computer control and data acquisition with Coriolis-based measurement instrumentation, SwRI precisely measures mass flow. Phase detectors and a powerful microprocessor supply basic measurements such as mass flow, density, and temperature.

While testing filter integrity, the bubble point test also helps measure the pore size of filter elements.

Filtering Efficiency Rating

To determine filter efficiency, a special valve allows contaminants to flow directly into the test filter. To rate filter elements and filter assemblies easily, this test method determines percent filtering efficiency on a single pass basis for specific contaminant particle sizes or size ranges.

Bubble Test

A submerged test filter is pressurized for the bubble/pore-size test, which determines the "bubble-all-over" point of test filters, measured in inches of water.

The absolute filter housing collects filter contaminants for analysis during single-pass particle retention and media migration tests.

Particle Counter

Samples of oils and hydraulic and transmission fluids are shaken vigorously to suspend minute particles. To determine "true cleanliness," a laser device counts and sizes particles for comparison to standard cleanliness levels. To determine the effectiveness of the test filter, the true cleanliness of sample fluids is measured before and after the filter test.

Oil Filter Test Stand

The Institute's multifunctional test facility simultaneously accommodates three different filters with differing flow rates in a single cabinet. The system tests oil, hydraulic, and fuel filters. All configurations meet SAE J806 specifications and can be modified for custom evaluations.

The Institute's filter test stand accommodates numerous types and sizes of oil filters.

For almost 15 years, the Institute has conducted oil filter testing according to SAE standards, continually improving capabilities and facilities. Experience includes:

  • Nuclear power plant filter testing
  • Locomotive filter testing for international clients
  • Custom filter testing for U.S. and international clients
  • Verification of engineering specifications for original filter manufacturers

The Institute tests spin-on or cartridge-type automotive, diesel, and locomotive filters and all sizes of lube oil, hydraulic, or fuel filters for a variety of contaminants. Flow rates from 0.5 to 60 gpm are tested at up to 250 F. Various contaminant injection systems, such as multi-pass injection and quadrant delivery, are investigated.

The Institute has an international reputation for the quality, consistency, and reliability of its tests.

This brochure was published in November 1999. For more information about oil filter testing, contact Larry Hollingsworth, Manager, Phone (210) 522-5711, Fuels and Lubricants Research Division, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510.

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