Residual analyzer assembly

• US 4,822,474 A
• Filed: 04/30/1987
• Issued: 04/18/1989
• Est. Priority Date: 04/30/1987
• Status: Expired due to Fees

• Current Assignee: Wallace & Tiernan Incorporated A Corporation OD Delaware
• Original Assignee: Pennwalt Corporation (Arkema)
• Inventors: Corrado, Daniel R.
• Primary Examiner(s): Tung, T.
• Application Number:
  US07/044,876
• Time in Patent Office: 719 Days
• Field of Search: 204/1 B, 204/1 T, 204/400, 204/412, 204/435, 204/402, 204/409, 73/863, 73/863.01, 73/863.02, 73/863.03
• US Class Current: 204/402
• CPC Class Codes: G01N 27/38 Cleaning of electrodes
• CPC Class Codes: G01N 27/404 Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid , e.g. Clark-type oxygen sensors

Abstract

A residual analyzer assembly including an analyzer probe, typically of the amperometric type having a stable zero calibration, and a working fluid sampler system having means for backflushing the flow so as to periodically cleanse the system. The residual analyzer probe having two bare electrodes operating as a working electrode and a counter electrode. The working electrode being formed in a double spiral helix with the counter electrode being formed in an outer peripheral ring closely adjacent the working electrode. The probe also including a third electrode within an electrolytic solution and positioned behind a membrane located directly behind the working electrode. The three electrode system operated utilizing a potentiostat type circuit. The working fluid sampler system adapted to sample a portion of the working fluid flow and maintain a constant pressure into a flow block. A controlled amount of reagent being added for proper residual analyzation of the sample. The sample flow being directed into an impeller chamber which provides a constant flow velocity directly adjacent the exposed electrodes of the analyzer probe. A backflush mechanism is also provided to cleanse the internal flow passageways of the system on a periodic basis.

Claims

1. A probe for residual analyzation of working fluid, the probe comprising:

three electrodes including a first electrode having a double spiral configuration, a second electrode forming an outer ring closely adjacent the first electrode, the first and second electrodes adapted for direct contact with the working fluid and a third electrode positioned within an electrolytic solution within an internal chamber in a probe body and a membrane immediately adjacent the first electrode, the membrane in communication with the third electrode through the electrolytic solution.

2. A probe as claimed in claim 1 further comprising means for operating the three electrodes in a potentiostat circuit with the first electrode acting as a working electrode, the second electrode acting as a counter electrode, and the third electrode acting as a reference electrode, a potential being maintained between the working and reference electrodes while current being permitted to flow only between the counter and working electrodes.

3. A probe as claimed in claim 1 wherein the first and second electrodes are made of a platinum.

4. A probe as claimed in claim 1 wherein the third electrode is made of a silver and is maintained within a potassium chloride electrolytic solution.

5. A probe as claimed in claim 1 wherein the membrane is a hydrophilic polypropylene.

6. A probe as claimed in claim 1 further comprising means to determine the level of electrolytic solution within the internal chamber of the probe.

7. A probe as claimed in claim 1 further comprising means to vent the internal chamber of the probe body.

8. A residual analyzer assembly comprising:

an amperometric probe including two exposed electrodes, one comprising a working electrode having a double spiral configuration and the other comprising a counter electrode forming a ring around the double spiral configuration, a chamber within the probe having an electrolytic solution therein, means defining a reference junction immediately adjacent the working and counter electrodes, and a reference electrode positioned within the chamber of said probe.

9. A residual analyzer assembly as claimed in claim 8 further comprising a working fluid sampler system having means for receiving a flow of working fluid and withdrawing a sample therefrom, means for maintaining a constant pressure on the sample, means for adding reagent to the sample, means for controlling the reagent reaction time with the sample, means for directing the sample into an impeller chamber and impeller means adapt to maintain a constant flow velocity adjacent the exposed electrodes of the probe.

10. A residual analyzer assembly as claimed in claim 9 further comprising means for periodically backflushing the working fluid through the reagent reaction control means, the reagent addition means and the fluid sampling means, opposite the normal sample flow direction.

11. A residual analyzer assembly as claimed in claim 10 further comprising means for applying a potential between one of the exposed electrodes and the third electrode and further adapted for permitting current flow only between the two exposed electrodes.

12. A residual analyzer assembly as claimed in claim 11 wherein the applying means operates in conjunction with a potentiostat circuit.

13. A residual analyzer assembly as claimed in claim 10 further comprising means to maintain a grit material within the impeller chamber for cleaning of the exposed electrodes of the probe.

14. A working fluid sampler assembly adapted for residual analyzation of a working fluid, the assembly comprising:

means for receiving a flow of working fluid, means for sampling the flow of working fluid, means for maintaining a constant pressure on the sample, means for adding reagent to the sample and further adapted to control the time of reaction of the reagent with the sample, means for directing the sample from the reagent addition means to an impeller means, said impeller means adapted to maintain a constant flow velocity adjacent a residual analyzer probe and means for periodically causing a backflush of the working fluid through the directing means, the reagent addition means and the sampling means, but not the impeller means, opposite the normal sample flow direction.

15. A working fluid sample assembly as claimed in claim 14 further comprising an amperometric probe having a stable zero calibration, the probe being positioned adjacent the impeller means.

16. A working fluid sample assemby as claimed in claim 15 wherein the probe comprises two exposed electrodes and a reference electrode within an electrolytic solution behind a membrane.

17. A working fluid sample assembly as claimed in claim 16 wherein the two exposed electrodes further comprise a double spiral wound working electrode and a substantially circular counter electrode surrounding the working electrode.

18. A working fluid sample assembly as claimed in claim 17 wherein the membrane is positioned behind the working electrode.

19. A working fluid sample assembly as claimed in claim 18 wherein the working and counter electrode are supported on a detachable cap.

20. A working fluid sample assembly as claimed in claim 19 wherein the membrane is supported on the probe behind the detachable cap.