Gas filter efficiency test equipment - using quasi-mono-disperse aerosols at flow rates encountered in service

摘要

Equipment for determining the sepn. efficiency of gas filters (esp. point-of-use fillers) has an electrostatic classifier (EC) unit, for producing a sub-micron quasi-monodisperse aerosol of known particle concn. from a polydisperse aerosol, and a particle counter, esp. a condensn. nucleous counter (CNC), for determining ultra-fine particles, the gas filter to be tested being placed between the EC unit and the CNC. (a) a venturi tube (9) is inserted between the EC unit and the gas filter, the EC unit being connected to the narrowest part (10) of the venturi tube for supplying the quasi-monodisperse aerosol at atmos. pressure; and (b) the inlet side of the venturi tube (9) is connected to an air line for supply of particle-free compressed air at more than 2 l/min. and at an entry pressure higher than atmos. pressure. Method of determining the sepn. efficiency of gas filters, using the equipment, is also described.