Method and apparatus for continuously monitoring an aqueous flow to detect and quantify ions

• US 5,990,684 A
• Filed: 12/02/1997
• Issued: 11/23/1999
• Est. Priority Date: 12/02/1997
• Status: Expired due to Fees

• Current Assignee: Brims Ness Corporation
• Original Assignee: John H. Merrill
• Inventors: Merrill, John H.
• Primary Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US08/984,256
• Time in Patent Office: 721 Days
• Field of Search: 324/439, 324/444, 324/71.1, 73/61.71, 340/627
• US Class Current: 324/439
• CPC Class Codes: G01N 27/10 Investigation or analysis specially adapted for controlling or monitoring operations or for signalling
• CPC Class Codes: G01N 33/1813 specific cations in water, e.g. heavy metals electrochemical analysis G01N27/26; detection of ions by colorimetry G01N31/22
• CPC Class Codes: G01N 33/1886 using probes, e.g. submersible probes, buoys

Abstract

A method and apparatus for detecting contaminants in an aqueous flow. The method involves providing a conduit having at least one ion collection portion, disposing the aqueous flow through the conduit, attracting target ions to the ion collection portion such that they are bonded to the ion collection portion, and detecting a contaminant, or contaminants, based upon a predetermined property of the plurality of target ions bonded to the ion collection portion. In the preferred embodiment of the method, the predetermined property is a conductivity of the target ions, and the detecting step involves measuring a change in conductivity of the collection portion as ions are bonded and comparing that conductivity to a predetermined conductivity. The apparatus includes a conduit into which an ion collection portion is disposed, a sensor that senses ions collected on the ion collection portion and sends a signal corresponding to a value of a predetermined property of the ions, and a microprocessor in communication with the sensor and programmed to process the signal and determine the presence of the at least one contaminant based upon the processed signal.

Claims

1. A method for detecting at least one contaminant in an aqueous flow comprising the steps of:

providing a conduit having at least one ion collection portion;

disposing the aqueous flow through the conduit;

attracting a plurality of target ions to said ion collection portion such that said plurality of target ions are bonded to said ion collection portion; and

detecting said at least one contaminant based upon a predetermined property of said plurality of target ions bonded to said ion collection portion.

2. The method as claimed in claim 1 wherein said predetermined property is a conductivity of said plurality of target ions and wherein said detecting step comprises the steps of:

measuring an initial conductivity of a said ion collection portion before said plurality of target ions are bonded to said ion collection portion;

measuring a plurality of subsequent conductivity'"'"'s of said ion collection portion while the target ions are bonded to said ion collection portion;

calculating a change in conductivity by comparing each of the subsequent conductivity'"'"'s to the initial conductivity; and

determining whether the change in conductivity differs from a predetermined change in conductivity.

3. The method as claimed in claim 2 wherein the measuring steps comprise the steps of:

providing a constant current power supply to a plurality of conductive pads disposed within said ion collection portion;

measuring a voltage of said power supply; and

comparing said voltage with a plurality of predetermined voltages corresponding to a plurality of conductivity'"'"'s.

4. The method as claimed in claim 3 further comprising the step of providing an alarm when said change in conductivity differs from said predetermined change in conductivity.

5. The method as claimed in claim 1 further comprising the step of disposing an ion exchange portion within said conduit, said step of disposing said ion exchange portion comprising the steps of:

disposing a predetermined ion exchange resin within said conduit; and

doping the plurality of target ions onto said ion exchange resin.

6. The method as claimed in claim 5 further comprising the steps of:

attracting ions of said contaminants having higher selectivity coefficients relative to said ion exchange resin than a selectivity coefficient of said target ions; and

exchanging said ions of said contaminants for said target ions doped to said ion exchange resin such that said ions of said contaminants are bonded to said ion exchange resin and such that said target ions are disposed within said aqueous flow.

7. The method as claimed in claim 1 further comprising the steps of:

measuring a value of said predetermined property;

comparing said value with a predetermined value of said predetermined property; and

providing an alarm when said value differs from said predetermined value.

8. The method as claimed in claim 1 further comprising the steps of:

measuring a value of said predetermined property; and

displaying said value such that said value is quantifiable to a user.

9. An apparatus for detecting at least one contaminant in an aqueous flow, said apparatus comprising:

a conduit;

an ion collection portion disposed within said conduit;

a sensor for sensing a plurality of ions collected on said ion collection portion and sending a signal corresponding to a value of a predetermined property of said ions; and

a microprocessor in communication with said sensor, said microprocessor being programmed to process said signal and determine the presence of said at least one contaminant based upon the processed signal;

wherein the aqueous flow flows through said conduit, a plurality of target ions are attracted to said ion collection portion and are bonded to said ion collection portion, said sensor senses the bonding of the target ions to said ion collection portion and sends a signal to said microprocessor corresponding to the value of the predetermined property of the target ions, and said microprocessor processes the signal and determines the presence of said at least one contaminant based upon the processed signal.

10. The apparatus as claimed in claim 9 wherein the predetermined property is a conductivity of said target ions and wherein said sensor comprises:

a sensor substrate comprising an insulator layer, conductive pads, and an ion collection layer, said collection layer being selective for the target ion;

a constant current power supply attached to said conductive pads; and

a voltmeter for measuring a voltage from said constant current power supply and for providing a signal corresponding to the voltage to said microprocessor;

wherein the target ions bond to the ion collection layer forming a conductive bridge between the conductive pads, the conductive bridge changes the voltage of the current flow through the conductive pads, said voltmeter detects this change in voltage and sends the corresponding signal to the microprocessor, and the microprocessor processes the signal and detects the presence of contaminants based upon the change in conductivity.

11. The apparatus as claimed in claim 10 wherein said ion collection layer comprises a polymer, said polymer being selective for the target ions.

12. The apparatus as claimed in claim 11 wherein said polymer is polyvinyl pyridine and wherein said target ions are copper ions.

13. The apparatus as claimed in claim 9 wherein said sensor senses ions selected from a group consisting of iron, zinc, cadmium, calcium, strontium, copper, mercury, lead, nitrate, and sulfate ions.

14. The apparatus as claimed in claim 9 further comprising an ion exchange portion disposed within said conduit at a position upstream of said ion collection portion and wherein said ion exchange portion comprises an ion exchange resin and a plurality of target ions doped to said ion exchange resin.

15. The apparatus as claimed in claim 14 wherein the predetermined property is a conductivity of said target ions and wherein said sensor comprises:

a sensor substrate comprising an insulator layer, conductive pads, and an ion collection layer, said collection layer being selective for the target ion;

a constant current power supply attached to said conductive pads; and

a voltmeter for measuring a voltage from said constant current power supply and for providing a signal corresponding to the voltage to said microprocessor;

wherein the target ions bond to the ion collection layer forming a conductive bridge between the conductive pads, the conductive bridge changes the voltage of the current flow through the conductive pads, said voltmeter detects this change in voltage and sends the corresponding signal to the microprocessor, and the microprocessor processes the signal and detects the presence of contaminants based upon the change in conductivity.

16. The apparatus as claimed in claim 15 wherein said ion collection layer comprises a polymer, said polymer being selective for the target ions.

17. The apparatus as claimed in claim 16 wherein said polymer is polyvinyl pyridine and wherein said target ions are copper ions.

18. The apparatus as claimed in claim 9 further comprising a display and wherein said microprocessor further comprises an output in communication with said display such that said display communications the value of the predetermined property such that said value is quantifiable to a user.

19. The apparatus as claimed in claim 9 further comprising an alarm and wherein said microprocessor further comprises an output in communication with said alarm such that said alarm is activated when the value of said predetermined property differs from a predetermined value.

20. The apparatus as claimed in claim 9 further comprising an additional sensor for sensing a plurality of additional ions and sending an additional signal to said microprocessor, and wherein said microprocessor is programmed to process said additional signal and detect an additional contaminant based upon the processed signal.