This Chart shows the actual amount of "Fine Test Dust" which was passed through two Donaldson air filters tested by Southwest Research Institute, an independent testing laboratory. Both of these filters were the same Donaldson model. One of the filters was "New", and the other filter had been used for a normal service interval and than cleaned on a ZAISER Cartridge Air Filter Dry Cleaning Machine.

As shown, the New Filter passed twice as much dust during the "Initial" phase of the test, and a total of 10% more dust throughout the entire testing period. A copy of the complete test report with all of the raw data is available for your review.