A cascade impactor is used when a particulate substance is moved through an opening using an aerosol. The impactor is used to measure the scope of the substance scope. Cascade impactors are strictly measurement related devices.
man with drill
In addition to measuring the range of substances moving through an aerosol opening, the impactor can also be used to determine the particle size of the delivered substance. A cascade impactor collects your samples in a graduated fashion. This allows the user to identify the particle sizes of the substance as the particles are distributed from the propellant aerosol source.
When the aerosol substance is distributed in the cascade impactor, the substance enters a series of discs designed to collect solids and different particles. The substance is thus collected as it passes through the series of disks. Each disc is placed in sequence with the previous and previous disc. The size of the discs is also graduated to correctly determine the size of the particulate material in each stage of the impactor.
There are typically ten different stages in a cascade impactor; the stages vary from large to small, depending on the substance being measured. The lighter the substance, the further it will travel to the impactor. Each impactor disc has its own speed, at which it is used to pick up the substance that passes through it. Once the pucks stop collecting any amount of matter, the user can determine the rate of dispersion of the substance driven by the aerosol.
The function of the cascade impactor is directly related to its design, which consists of a motorized flow chamber that contains all the discs. Each disk within the flow chamber represents an impactor stage. Each stage acts as a guide for the user to determine the rate of dispersion of the substance.
As the substance is distributed to the inner workings of the impactor, the disks at each stage accumulate whatever considerable amount of particulate or solid matter they are capable of. This allows smaller and smaller solid particles to pass to the next stage of the impactor. Since each disc has its own collection speed, the flow chamber picks up speed towards the end of the impactor. This allows the collection of the finest particles all the way to the end of the impactor.