Apparatus for measuring a liquid specimen

• US 5,007,296 A
• Filed: 10/19/1989
• Issued: 04/16/1991
• Est. Priority Date: 01/26/1989
• Status: Expired due to Fees

• Current Assignee: Toa Medical Electronics Co., Ltd.
• Original Assignee: 501 TOA Medical Electronics Company Limited
• Inventors: Hukuhara, Takahito
• Primary Examiner(s): Noland, Tom
• Application Number:
  US07/424,343
• Time in Patent Office: 544 Days
• Field of Search: 324/724, 324/71.1, 324/71.4, 324/464, 324/425, 324/439, 324/446, 324/450, 324/65 P, 73/864.81-864.87, 204/400, 204/403, 204/409, 356/402, 356/410, 356/411, 377/12
• US Class Current: 73/864.87
• 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
• CPC Class Codes: G01N 15/13 Details pertaining to apertures
• CPC Class Codes: G01N 2015/133 Flow forming
• CPC Class Codes: G01N 2015/135 Electrodes
• CPC Class Codes: G01N 35/1097 characterised by the valves valves in general F16K

Abstract

A particle detector for detecting particles of blood components in an electrolyte employs a minute hole through which a fixed quantity of the material is drawn. Electrodes inside and outside the detector pass an electric current through the minute hole. When a particle passes through the hole, it partially blocks the hole, whereby a sharp change is experienced in the amount of current passing through the electrolyte. A syringe fluid path in the detector enters the fluid path for the test fluid at right angles thereto. The inside electrode is disposed in the syringe fluid path near its junction with the fluid path for the test fluid. A colorimeter is placed in series with the flow of the test fluid to measure the concentration of hemoglobin in the test fluid. Automated control of the particle detector is provided by a plurality of cams driving a corresponding plurality of pistons. One of the pistons serves as a syringe for pumping test fluid during a test and for pumping purge fluid for cleanup prior to the next test. The remaining pistons, with interconnecting chambers, perform valve functions.

Claims

1. A particle detector for detecting particles in an electrolyte, comprising:

a body;

means for forming an aperture in said body;

a fluid path in said body communicating with said aperture;

a syringe liquid path in said body communicating with said aperture;

said syringe liquid path terminating in said fluid path;

a first electrode in said body;

said first electrode being disposed in said syringe liquid path near a junction of said syringe liquid path with said fluid path;

a second electrode external to said body;

a colorimeter in series flow with said fluid path; and

means for preventing direct electrical conduction through said body, whereby electrical conduction between said first and second electrodes is constrained to flow in said electrolyte through said aperture.

2. A particle detector for detecting particles in an electrolyte, comprising:

a body;

means for forming an aperture in said body;

a fluid path in said body communicating with said aperture;

a syringe liquid path in said body;

said syringe liquid path terminating in said fluid path;

a first electrode in said body;

said first electrode being disposed in said syringe liquid path near a junction of said syringe liquid path with said fluid path;

a second electrode external to said body; and

means for preventing direct electrical conduction through said body, whereby electrical conduction between said first and second electrodes is constrained to flow in said electrolyte through said aperture;

said second electrode being disposed on an external surface of said body.

3. A particle detector according to claim 2, wherein said second electrode is a metallic layer plated on said external surface.

4. A particle detector according to claim 3, wherein said metallic layer is chromium.

5. A system for detecting particles in an electrolyte, comprising:

a detector;

an aperture in said detector;

a liquid path in said detector communicating with said aperture;

a syringe liquid path in said detector communicating with said aperture;

said syringe liquid path terminating in said liquid path;

means for moving a predetermined fixed quantity of said electrolyte through said aperture and said liquid path;

means for measuring an electrical resistance of said electrolyte through said aperture;

a colorimeter in said liquid path; and

said colorimeter being of a type effective for measuring a density of a color of said electrolyte passing therethrough.

6. A detector for detecting particles in an electrolyte comprising:

a body;

a liquid path in said body;

an aperture in said body;

a cross bore in said body communicating with said aperture and said liquid path;

a syringe liquid path in said body;

said syringe liquid path intersecting said cross bore, generally at right angles, at a point intermediate said aperture and said liquid path, whereby fluid flow between said aperture and said liquid path passes said syringe liquid bore, generally at right angles; and

an electrode in said syringe liquid path.

7. A detector according to claim 6, further comprising:

a second electrode external to said body; and

said second electrode being a metallic coating affixed to an external surface of said body.