The Serial Flow Diffusion Battery is most useful when determination of submicron particle number is important and when sampling from a stable aerosol source.  This type of diffusion battery consists of a series of diffusion chambers placed one behind the other.  Each stage provides a longer diffusion length than the stages in front of it.  Aerosol is passed through the series of diffusion cells in a laminar stream.  Particle penetration through each successive stage in the serial diffusion battery decreases.  In order to determine how many particles pass through each stage, a particle counter such as the condensation nucleus counter is used to count the particles in a fraction of the air flowing through each stage. 

The Parallel diffusion battery is useful in determining the mass fraction of submicron aerosols or when chemical and microscopic examination of collected submicron aerosol particles is important.  This diffusion battery can be used with stable and unstable aerosol sources.  This diffusion battery uses stages of increasing diffusion length, but provides for a different arrangement of the stages.  In this device, stages of increasing diffusion length are placed parallel to each other.  The instrument is arranged so that the same air flow rate passes through each stage or cell of the instrument and each cell samples the input aerosol.  Behind each stage an absolute filter counter of similar optical system to count the number of particles passing each stage, the filters can be weighed or analyzed chemically to determine the mass of particles passing through each diffusion stage.     

Stock # 02-800  Serial Flow Diffusion Battery