Title: Bounceless high pressure drop cascade impactor and a method for determining particle size distribution of an aerosol

• Summary
• Claims
• Description
• View all

Abstract: This invention is directed to a high pressure drop cascade impactor wherein the particles do not bounce from the collection plate; to a method for designing said impactor; a method for calculating and determining the particle size distribution of an aerosol wherein the particle size may have a Stokes (aerodynamic) diameter as small as 10 nanometers; and to a method of manufacturing such an impactor. The impactor that is the subject of this invention is different from and superior to previously described impactors in the following principal respects: 1. The particles exhibit substantially no reentrainment, or bounce, from the collection surfaces. This property is achieved by (a) limiting the exit jet stream velocities such that the herein defined "bounce parameter", .beta., is never exceeded, and (b) increasing the thickness of the jet plates to elongate the jet passageways in order to reduce the jet velocities so that bounce will not occur. 2. The impactor described herein eliminates turbulence near the entrances to the jet holes by rounding the edges of the jet holes. This is accomplished on the small holes by means of electropolishing. 3. The impactor described herein is capable of capturing particles as small as 40 nanometers Stokes (aerodynamic) diameter. By contract, previously described impactors could capture particles only as small as 300 nanometers Stokes diameter.


Do you think this is a good invention? Vote now: