PARTICLE VOLUME AND CROSS-SECTION MEASUREMENT

• US 3,793,587 A
• Filed: 03/08/1972
• Issued: 02/19/1974
• Est. Priority Date: 03/10/1971
• Status: Expired due to Term

• Current Assignee: Jurgen Schulz, Reinhard Thom
• Original Assignee: Jurgen Schulz, Reinhard Thom
• Inventors: Thom, Reinhard, Schulz, Jurgen
• Primary Examiner(s): Krawczewicz, Stanley T.
• Application Number:
  US05/232,741
• Time in Patent Office: 713 Days
• Field of Search: 324/71CP 235/92PC
• US Class Current: 324/71.1
• CPC Class Codes: G01N 15/134 Devices using two or more apertures

Abstract

An apparatus for counting and classifying particles suspended in a test liquid, wherein two measuring openings are aligned, are spaced from one another, and dimensioned differently, such that a particle volume measurement may be obtained at one of the measuring openings and a particle cross section measurement may be obtained at the other of the measuring openings; a tube outlet section aligned with the measuring openings and situated spaced from a first of the measuring openings on the side of the first measuring opening opposite to the side facing the second of the measuring openings, for conducting test liquid toward said first measuring opening; the diameters of the measuring openings, the spacing between the two measuring openings, and the spacing between the first measuring opening and the outlet of the tube outlet section being of the same order of magnitude; and a vessel surrounding the tube outlet section and the measuring openings for enabling the tube outlet section and the measuring openings to be immersed in an electrolyte.

Claims

1. An apparatus for counting and classifying particles suspended in a test liquid, comprising, in combination, means forming two measuring openings aligned, spaced from one another, and dimensioned differently, whereby a particle volume measurement may be obtained at one of the measuring openings and a particle cross section measurement may be obtained at the other of the measuring openings;

tube means having an outlet section aligned with said measuring openings and situated spaced from a first of said measuring openings on the side of said first measuring opening opposite to the side facing the second of the measuring openings, for conducting test liquid toward said first measuring opening;

the diameters of said measuring openings, the spacing between said two measuring openings, and the spacing between said first measuring opening and the outlet of said tube means being of the same order of magnitude; and

vessel means surrounding said outlet section and said measuring openings for enabling said outlet section and said measuring openings to be immersed in an electrolyte.

2. An apparatus as claimed in claim 1, wherein the diameter of said second measuring opening is larger than the diameter of said first measuring opening.

3. An apparatus as claimed in claim 1, wherein said first measuring opening has a cylindrical shape, with a length of about 15 microns and a diameter of about 40 microns.

4. An apparatus as claimed in claim 1, wherein said first measuring opening has a conical shape, with a length of about 22 microns, an inlet diameter of about 50 microns, and an outlet diameter of about 43 microns.

5. An apparatus as claimed in claim 1, wherein at least the outlet section of said tube means, and the means forming the first measuring opening, include building blocks containing said outlet section and said first measuring opening, and a support element means for holding the outlet section spaced from the first measuring opening.

6. An apparatus as claimed in claim 5, further comprising means for exchangeably mounting said support element means relative to said vessel means.

7. An apparatus as claimed in claim 6, wherein said vessel means includes a dividing wall and said support element means forms a part of said dividing wall.

8. An apparatus as claimed in claim 5, wherein said support element means includes a tube and said building blocks are located in said tube.

9. An apparatus as claimed in claim 7, wherein said support element means includes a tube, said building blocks are located in said tube, and said tube is fitted into mating receiving areas in said dividing wall.

10. An apparatus as claimed in claim 8, said tube having hole means located for placing chamber area within said tube and between said building blocks in communication with the surrounding of the tube.

11. An apparatus as claimed in claim 1, wherein the outlet section of said tube means and the means forming said measuring openings include building blocks containing said outlet section, said fIrst measuring opening, and said second measuring opening, and a support element means for holding the outlet section spaced from the first measuring opening and the first measuring opening spaced from the second measuring opening, and wherein said support element means includes a tube and said building blocks are located within said tube.

12. An apparatus as claimed in claim 11, said tube having hole means located for placing chamber area within said tube and between said building blocks in communication with the surrounding of the tube, with the hole means opening into the area between said outlet section and said first measuring opening being angularly offset with respect to the hole means opening into the area between said first measuring opening and said second measuring opening.

13. An apparatus as claimed in claim 10, said hole means having conical shapes.

14. An apparatus as claimed in claim 8, said tube containing a capillary tube means for conducting test liquid, said capillary tube means reaching to the side of said outlet opening opposite to that facing said first measuring opening.

15. An apparatus as claimed in claim 9, wherein the mating portions of said tube and dividing wall are conically shaped.

16. An apparatus as claimed in claim 8, wherein said tube is glass and the building blocks are drilled saphires glass-bonded to the inner surface of said tube.

17. In an apparatus for counting and classifying particles suspended in a test liquid, which apparatus operates according to the Coulter process and includes a first vessel containing electrolyte, a second vessel whose interior is in communication with the interior of the first vessel through a first small measuring opening through which electrolyte can flow from the first vessel into the second vessel, a device for feeding the test liquid to the measuring opening and whose outlet opening is located upstream coaxially and a small distance before the measuring opening such that electrolyte flowing into the measuring opening sucks test suspension out of the outlet opening and transports it into the center of the measuring opening, and electrodes placed at different electric potentials and arranged to reach down into the liquid in the vessels, with the electrodes being connected to an electrical circuit in which a current change is caused by the movement of a particle through the measuring opening, the amplitude of such current change being a measure of the size of the particle, the improvement comprising means presenting a second measuring opening arranged after the first measuring opening in the liquid stream, the opening diameters and/or the lengths of the two measuring openings being coordinated with one another such that one measuring opening allows essentially the volume and the other measuring opening essentially the cross section of the particles to be measured.

18. A method of using an apparatus for counting and classifying particles suspended in a test liquid and composed of two measuring openings which are aligned, spaced from one another, and dimensioned differently, whereby a particle volume measurement may be obtained at one of the measuring openings and a particle cross section measurement may be obtained at the other of the measuring openings;

a tube having an outlet section aligned with the measuring openings and situated spaced from a first of the measuring openings on the side of the first measuring opening opposite to the side facing the second of the measuring openings, for conducting test liquid toward the first measuring opening;

the diameters of the measuring openings, the spacing between the two measuring openings, and the spacing between the first measuring opening and the outlet of the tube being of the same order of magnitude; and

a vessel surrounding the outlet section and the measuring openings for enabling the outlet section and the measuring openings to be immersed in an electrolyte;

the method comprising placing a suspension of particles in said tube means, immersing said outlet section and said measuring openings in electrolyte, hydrodynamically sucking said suspension from the tube means and injecting it into the center of said first measuring opening including flowing entraining electrolyte into said first measuring opening toward said second measuring opening.

19. A method as claimed in claim 18, further comprising flowing the electrolyte and entrained suspension coming from said first measuring opening homogeneously from the first measuring opening into the second measuring opening.

20. A method as claimed in claim 18, further comprising matching the lengths of the particles and the length of said first measuring opening such that the length of the first measuring opening is shorter than the lengths of the particles.

21. A method as claimed in claim 18, further comprising flowing a greater amount of electrolyte through said second measuring opening than comes from said first measuring opening.

22. A method as claimed in claim 18, further comprising choosing said particles to include deformable particles and matching the dimensions of said measuring openings to the dimensions of the deformable particles such that the deformable particles are essentially deformed only in one of the measuring openings.

23. A method as claimed in claim 18, further comprising placing electrodes of different potential on either end of said other measuring opening for creating an electric field through said other measuring opening, and matching the lengths of the particles and the length of said other measuring opening such that the particle remains partially in a region of weakened field strength, when passing through the measuring opening.

24. A method as claimed in claim 18, further comprising focusing said suspension at said first measuring opening substantially in the absence of an electric field and measuring particle volume at said second measuring opening by sensing resistance changes in the resistance of said second measuring opening.

25. A method as claimed in claim 18, further comprising sensing the amplitudes of particle-caused changes in the electrical resistance of said other opening, for determining particle cross sections.

26. A method as claimed in claim 18, further comprising sensing the durations of particle-caused changes in the electrical resistance of said other opening, for determining particle cross sections.

27. A method as claimed in claim 18, further comprising sensing the amplitudes and the durations of particle-caused changes in the electrical resistance of said other opening, for determining particle cross sections.

28. A method as claimed in claim 27, further comprising forming the ratio of duration to amplitude, for determining particle cross sections.

29. A method as claimed in claim 18, further comprising sensing only changes in the electrical resistance of said other opening which exceed a predetermined amplitude, for determining particle cross sections.

30. A method as claimed in claim 18, further comprising sensing as the durations of particle-caused changes in the electrical resistance of said other opening those portions of changes lying above a predetermined amplitude level, for determining particle cross sections.

31. A method as claimed in claim 18, further comprising sensing as the durations of particle-caused changes in the electrical resistance of said other opening those portions of changes lying between the reaching of the maximum change and the fall to a predetermined percentage of the maximum change, for determining particle cross sections.