Water analyzer with multiple electrodes

• US 5,103,179 A
• Filed: 03/05/1990
• Issued: 04/07/1992
• Est. Priority Date: 03/05/1990
• Status: Expired due to Term

• Current Assignee: Industrial Chemical Measurement Incorporated, OI Corporation (Xylem, Inc.)
• Original Assignee: Industrial Chemical Measurement Incorporated
• Inventors: Westlake, Richard T., Evers, Kenneth J., Thomas, Frank A.
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): Brown, Glenn W.
• Application Number:
  US07/489,444
• Time in Patent Office: 764 Days
• Field of Search: 324/438, 324/441, 324/439, 204/402, 204/412, 204/415, 204/420
• US Class Current: 324/438
• CPC Class Codes: G01N 33/1886 using probes, e.g. submersible probes, buoys

Abstract

A water analyzer having several electrodes of the type which normally interfere with one another. These electrodes include a first electrode which is an active measurement electrode which perturbs the solution in which it is used and a second electrode whose reading is affected by the operation of the first electrode. Accurate readings are provided by sequencing the operation of the electrodes so that they are not always operating at the same time. In addition, further correction of the readings is provided to compensate for the known error resulting from the operation of the active electrode or electrodes. Such electrodes read conditions such as pH, dissolved oxygen and conductivity.

Claims

1. A water analyzer having a plurality of electrodes, including electrodes which interfere with one another, for measuring a plurality of conditions, said analyzer comprising:

a first electrode of the type which uses an active measurement which perturbs the solution in which it is used when it is energized;

a second electrode of the type whose reading is affected by the operation of the first electrode, said second electrode being positioned in a fixed relationship with respect to the first electrode; and

sequencing means which activate said first electrode at a time different from the reading of said second electrode.

2. The water analyzer of claim 1 further including a digital data readout area and said water analyzer including memory means to display a plurality of readings simultaneously on said digital data readout area even though the readings are taken sequentially.

3. A water analyzer having a plurality of electrodes, including electrodes which interfere with one another, for measuring a plurality of conditions for a period of time even after such electrode has been de-energized, said analyzer comprising:

a first electrode of the type which is an active measurement which perturbs the solution in which it is used when it is energized;

a second electrode of the type whose reading is affected by the operation of the first electrode, said second electrode being positioned in a fixed relationship with respect to the first electrode;

sequencing means which activate said first electrode at a time different from the reading of said second electrode; and

preset correction means which correct the readings of said second electrode based upon its interaction with the first electrode.

4. The water analyzer of claim 3 wherein said preset correction means comprise a microprocessor including memory.

5. The water analyzer of claim 3 wherein said first electrode is a dissolved oxygen sensing electrode.

6. The water analyzer of claim 3 wherein said second electrode is a pH sensing electrode.

7. The water analyzer of claim 3 wherein said first electrode is a dissolved oxygen electrode, and said second electrode is a pH sensing electrode.

8. The water analyzer of claim 7 further including electronic temperature sensing means.

9. The water analyzer of claim 8 further including a pair of conductivity electrodes.

10. The water analyzer of claim 9 wherein said sequencing means first activates the temperature sensing means and the dissolved oxygen electrode, then, after a delay of at least one second, deactivates the dissolved oxygen electrode and, at about the same time, activates the pH electrode, then, after about one second, deactivates the pH electrode and activates the conductivity electrodes and the dissolved oxygen electrode, then, after about two seconds deactivates the conductivity electrodes and the reads the results of the dissolved oxygen electrode about eight seconds after its first activation.

11. The water analyzer of claim 10 wherein the results of the readings of the temperature sensing means and the four electrodes are fed into microprocessing means wherein the readings are corrected for the previously determined error caused by the interference among the electrodes.

12. The water analyzer of claim 11 wherein the reading of the dissolved oxygen electrode is corrected for the previously determined error caused by interference from the electrodes which read temperature, conductivity and pH.

13. The water analyzer of claim 12 wherein said water analyzer has a digital readout of temperature, dissolved oxygen, pH and conductivity which are read out simultaneously.