Patent ID: 8071940
Filing Date: 2011-12-06
Classification: G01N

Abstract:
1. A sheath gas extraction system adapted to be engaged to a Vienna type differential mobility analyzer (DMA) to reduce the pressure drop in the DMA while providing an axisymmetric flow, the DMA comprising a first portion comprising an inner electrode support and a second portion comprising a particle classification section outlet, the sheath gas extraction system comprising: a first isolating piece ( 3 ) made from a substantially insulating and chemically inert material, wherein the first isolating piece ( 3 ) is substantially axisymmetric and comprises at least two slots (A) substantially around a revolution axis; a second stabilizing piece ( 2 ) made from a conductive material, wherein the second stabilizing piece ( 2 ) is substantially conic and comprises a substantially circular orifice along the revolution axis; and a third extraction piece ( 1 ) made from a substantially insulating and chemically inert material, wherein the third extraction piece ( 1 ) is substantially convergent in a downstream direction and tubular, the sheath gas extraction system being arranged in a downstream configuration wherein: the first isolating piece ( 3 ) is adapted to engage with the first portion of the DMA at the particle classification section outlet and with the second stabilizing piece ( 2 ); the second stabilizing piece ( 2 ) is adapted to engage with the first isolating piece ( 3 ); and the third extraction piece ( 1 ) is adapted to engage with the first isolating piece ( 3 ).