초록 ▼

An apparatus for analyzing particles, adapted to operate continuously even in the absence of particles contained in a sample medium, includes a sensing region and a particle analyzer associated therewith. A fluid flow path, preferably air flow, causes a sample medium with particles therein to flow t

An apparatus for analyzing particles, adapted to operate continuously even in the absence of particles contained in a sample medium, includes a sensing region and a particle analyzer associated therewith. A fluid flow path, preferably air flow, causes a sample medium with particles therein to flow through the sensing region. Another fluid flow path ensheathes the sample medium with a flowing sheath fluid for hydrodynamically focusing the particles as they pass through the sensing region. The sheath fluid is adapted to flow at a first flow rate compatible with the flow rate of flowing particles. When the apparatus is operating in the absence of a sample medium, the sheath fluid is controlled to flow at a second flow rate, slower than the first flow rate, for collection thereof.

대표청구항 ▼

In a hydrodynamically focused fluid flow system of the type having an aperture through which particles to be analyzed flow, air flow means associated with a sample fluid containing said particles for causing said particles to flow through said aperture, sheath fluid flow means for providing a flow o

In a hydrodynamically focused fluid flow system of the type having an aperture through which particles to be analyzed flow, air flow means associated with a sample fluid containing said particles for causing said particles to flow through said aperture, sheath fluid flow means for providing a flow of sheath fluid around said sample fluid for focusing said particles which flow through said aperture, and means for analyzing said particles which flow through said aperture, wherein the improvement comprises: an antechamber in fluid communication with said air flow means, said sheath fluid flow means and a sheath fluid reservoir containing said sheath fluid, said reservoir also being in fluid communication with said air flow means, said antechamber including a first operable valve which allows sheath fluid to flow from said reservoir to said antechamber but restricts reverse flow if the pressure in the antechamber is higher than the pressure in the reservoir, said antechamber including a second operable valve which closes when the antechamber is full of sheath fluid and prevents sheath fluid from flowing into said air flow means, whereby flow of sheath fluid toward said aperture and flow of air for forcing said particles from the sample fluid through said aperture in a hydrodynamically focused flow are established.