Aperture tube structure for particle study apparatus

Claim 1

IN A PARTICLE MEASURING APPARATUS INCLUDING A CONTAINER OF LIQUID SUSPENSION TO BE TESTED, AN APERTURE TUBE EXTENDING INTO SAID CONTAINER, A VACUUM SOURCE FOR MOVING THE LIQUID FROM THE CONTAINER INTO AND THROUGH THE APERTURE TUBE, MEANS ESTABLISHING AN ELECTRICAL FIELD BETWEEN SAID CONTAINER AND THE APERTURE TUBE, AND A DETECTOR, THE IMPROVEMENT COMPRISING THE APERTURE TUBE HAVING FIRST AND SECOND CHAMBERS, AN APERTURE IN THE FIRST CHAMBER IN COMMUNICATION WITH THE LIQUID SUSPENSION IN THE CONTAINER, A CONDUIT EXTENDING FROM THE SECOND CHAMBER INTO THE FIRST CHAMBER AND HAVING ONE OPEN END TERMINATING AT A POINT CLOSELY SPACED FROM AND DIRECTLY OPPOSITE THE INTERIOR OF SAID APERTURE, MEANS CONNECTING SAID SECOND CHAMBER TO SAID VACUUM SOURCE AND MEANS TO INITIALLY FILL BOTH THE FIRST AND SECOND CHAMBERS WITH THE LIQUID SUSPENSION, AND SAID MEANS ESTABLISHING AN ELECTRICAL FIELD INCLUDING A FIRST ELECTRODE IN SAID CONTAINER AND A SECOND ELECTRODE IN SAID APERTURE TUBE, WHEREBY THE SUSPENSION WILL FLOW FROM THE CONTAINER THROUGH THE APERTURE AND INTO SAID CONDUIT AND THEN INTO SAID SECOND CHAMBER.