Patent ID: 8813582

Claim:
A testing system to test the efficiency of HEPA filters, comprising: means to hold a test filter, means to generate an aerosol upstream of said test filter, and means to direct said aerosol to said test filter, means to direct said aerosol upstream of said filter to a dilution system, said dilution system, comprising: a test portion comprising a first means for diluting said aerosol, a calibrate portion for calibrating the test portion, the calibrate portion comprising a second means for diluting said aerosol, and means to link the test portion and calibrate portion such that during calibration of the test portion, said aerosol first enters the calibrate portion and from the calibrate portion a diluted aerosol enters the test portion, and wherein during test mode only the test portion is used to dilute said aerosol; a sampling system to receive diluted aerosol samples from said dilution system and for receiving filtered aerosol samples downstream of said HEPA test filter; and a particle measuring system coupled to said sampling system to measure aerosol particle counts of said diluted aerosol samples from said dilution system and aerosol particle counts from said filtered aerosol samples downstream of said HEPA test filter, and wherein said particle measuring system includes a fan for drawing in ambient air, said particle measuring system having a sample inlet and an exhaust outlet and wherein the sample inlet and exhaust outlet of said article measuring system are both connected to the sampling system.