GATING FLOW CELL STRUCTURE FOR CONTINUOUS-FLOW ANALYSIS SYSTEMS

• US 3,811,841 A
• Filed: 08/09/1972
• Issued: 05/21/1974
• Est. Priority Date: 08/09/1972
• Status: Expired due to Term

• Current Assignee: Technicon Instruments Corporation (Bayer AG)
• Original Assignee: Aaron Kassel
• Inventors: Kassel, Aaron
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Serwin, R. E.
• Application Number:
  US05/279,149
• Time in Patent Office: 650 Days
• Field of Search: 23/230,253,259 324/71R,65R,65B 250/218
• US Class Current: 422/82
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 35/08 using a stream of discrete samples flowing along a tube system, e.g. flow injection analysis

Abstract

A flow cell structure having a sight passageway for analyzing a series of liquid samples separated by a segmentizing medium, e.g. air or other inert gas, includes at least three electrodes in electrical contact with the segmented sample stream passing therealong. The electrodes are disposed with respect to the sight passageway and in a ratio system, so as to indicate the presence of segmentizing medium in the sight passageway and deactivate the recorder.

Claims

2. A flow cell structure comprising:

means defining a sight passageway, fluid inlet and fluid outlet means connected to said passageway and defining with said passageway a conduit system, means for passing a fluid stream along said conduit system, said fluid inlet and said fluid outlet means including first and second electrodes, respectively, a third electrode disposed in said conduit system between said first and second electrodes, said first, second and third electrodes adapted to be in electrical contact with said stream, and means for determining a change in the ratio of the respective conductivities of portions of said stream flowing along said conduit system between said first and third electrodes and said third and second electrodes, respectively.

3. A flow cell structure as defined in claim 2, wherein said determining means comprises a bridge-type arrangement.

4. A flow cell structure as defined in claim 2, wherein, at least, said first and second electrodes are tubular electrodes.

5. A flow cell structure as defined in claim 2, wherein selected ones of said first, second and third electrodes are wire electrodes.

6. A flow cell structure as defined in claim 2, wherein said passing means includes means for directing a stream of liquid samples separated one from the other by a segmentizing fluid, said segmentizing fluid and said liquid samples having different conductivities, the volume of each liquid sample being, at least, equal to the volume of the conduit system between said first and second electrodes, whereby only a single segment of said segmentizing fluid is located along said conduit system and between said first and second electrodes at any one time.

7. A flow cell structure as defined in claim 6, comprising means for passing a measuring beam along the axis of said sight passageway, so as to analyze portions of said stream passing therealong, means including a recorder for recording the intensiTy of said light beam passed along said sight passageway, and means responsive to said determining means for controlling said detector.

8. A flow cell structure as defined in claim 7, wherein said disabling means includes a track/hold circuit.

9. A flow cell structure comprising sight passageway means and fluid inlet means and fluid outlet means defining a conduit system, means for passing a fluid stream along said conduit system, means for analyzing said stream passing along said passageway means, first, second, third and fourth electrode means in electrical contact with said stream flowing along a portion of said conduit system, and means interconnecting said first, second, third and fourth electrode means for indicating a change in the conductivity of said stream passing along said portion of said conductivity system.

10. A flow cell structure as defined in claim 9 wherein, said indicating means includes first means for indicating a change in the ratio of the respective conductivities of portions of said liquid stream passing between said first and third electrode means and said third and second electrode means and, also, second means for indicating a change in the ratio of the respective conductivities of portions of such stream passing between said first and fourth electrodes and said fourth and second electrodes, respectively.

11. A flow cell structure as defined in claim 10 including control means responsive to said first and second means upon a change in either of said ratios.