Continuous-flow, resistive-particle counting apparatus

• US 4,103,229 A
• Filed: 01/28/1977
• Issued: 07/25/1978
• Est. Priority Date: 01/28/1977
• Status: Expired due to Term

• Current Assignee: University of Virginia
• Original Assignee: University of Virginia
• Inventors: Gear, Adrian R. L.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Sunderdick, Vincent J.
• Application Number:
  US05/763,630
• Time in Patent Office: 543 Days
• Field of Search: 324/71 CP, 324/71 R, 73/432 PS
• US Class Current: 324/71.1
• CPC Class Codes: G01N 15/12 by observing changes in resistance or impedance across apertures when traversed by individual particles, e.g. by using the Coulter principle

Abstract

Apparatus for continuous-flow resistive-particle counting includes an injection jet directed at a counting or sensing orifice, particle-containing electrolyte being pumped through the jet in an amount which is in excess of the volume flow rate normally passing through the sensing orifice. The orifice therefore only detects and analyzes the particles contained in the injected solution and not in the bulk electrolyte disposed within the external vessel. Internal and external electrodes are respectively disposed upon opposite sides of the orifice, that is, within the sensing orifice tube and within the external vessel and the electrical connection between the electrodes is maintained at all times. Performance in measuring erythrocyte and platelet numbers and size is very comparable to that of static, resistive-particle counting. The apparatus further includes a simple overflow, fluidically connected to the external vessel, which serves as a drain for the excessively pumped solution, and the injection jet is vertically and pivotably adjustable so as to properly orient the same with respect to the sensing orifice.

Claims

1. Continuous-flow resistive-particle counting apparatus comprising:

container means for housing a bulk electrolyte;

an orifice tube closed at the lower end thereof and having a sensing orifice defined within a side wall portion thereof, a portion of said electrolyte thereby being disposed within said tube;

a first electrode disposed within said electrolyte disposed within said orifice tube;

a second electrode disposed within said bulk electrolyte disposed within said container;

electric circuit means including a power source, electrically connecting said first and second electrodes;

fluid pumping means having a down-stream tube equipped with an injection jet, said down-stream tube disposed within the electrolyte in said container at a position radially outwardly of said orifice tube and within the vicinity of said sensing orifice of said orifice tube for forcefully injecting a fluid jet of said particles to be counted toward said sensing orifice at a flow rate which is at least ten-fold the normal flow rate of said electrolyte from said container through said sensing orifice into said orifice tube; and

means disposed within said electrical circuit for counting said particles passing through said sensing orifice.

2. Continuous-flow resistive-particle counting apparatus as set forth in claim 1, further comprising:

a holding block disposed about said orifice tube and having a selectively variable diameter so as to selectively grasp or release said orifice tube and thereby render said block selectively fixed about said tube, or vertically movable or pivotable about the longitudinal axis of said tube, respectively;

means for controlling the diameter of said block; and

said injection means includes an injection jet tube fixedly disposed within said block, said injecting tube having an injection jet defined within the end thereof disposed within said vicinity of said sensing orifice,

whereby the disposition of said injection jet relative to said sensing orifice is adjustable.

3. Continuous-flow resistive-particle counting apparatus as set forth in claim 2, wherein:

said block is substantially C-shaped in horizontal cross-section; and

said means for controlling the diameter of said block is a threaded fastener threadedly engaged within the arms of said block defining said C-shaped portion thereof.

4. Continuous-flow resistive-particle counting apparatus, as set forth in claim 1, further comprising:

overflow means defined within said bulk electrolyte container.