Particle analyzing apparatus and fluid circulating system therefor

Claim 1

A particle analyzing apparatus and fluid circulating system therefor comprising, a vessel having a first chamber and a second chamber with a wall therebetween separating said chambers, said first chamber including a cap and a passageway in said cap providing access to said first chamber, said wall having a passageway therein providing communication between said first and second chambers, said passageways in the cap and wall being axially aligned one with the other, an elongate director removably positioned within said passageways, said director having a bore therein extending the length thereof from an entrance end to a terminus of the director, an aperture retaining member removably positioned on the director at said terminus, said aperture retaining member having an aperture therein spaced from the director terminus to permit passage of particle free liquid from said first chamber through said aperture and into said second chamber, the aperture and director bore being coaxial, a liquid transmission conduit extending from an opening in said second chamber to at least one opening in said first chamber, means in said liquid transmission conduit for continuously re-circulating particle free liquid from said second chamber back to said first chamber through the space between the director terminus and the aperture to pass through the aperture and return to the second chamber, means to feed particles into said director at the entrance end such that said particles move through the bore to the director terminus, a first electrode in the first chamber and a second electrode in the second chamber to establish an electrical field in the aperture between said chambers, means including electrical leads connected to the electrodes and adapted to extend connections to a detector to respond to electrical measuring signals produced across said electrodes with passage of particles through said aperture, whereby particles introduced to said director will move therethrough and pass through the center of the aperture into the second chamber simultaneously with passage of re-circulated particle free liquid through the aperture.