Compact high resolution under wire water weight sensor array

• US 6,087,837 A
• Filed: 11/21/1997
• Issued: 07/11/2000
• Est. Priority Date: 12/13/1996
• Status: Expired due to Term

• Current Assignee: Honeywell-Measurex
• Original Assignee: Honeywell-Measurex
• Inventors: Chase, Lee
• Primary Examiner(s): BROWN, GLENN WARNER
• Application Number:
  US08/977,773
• Time in Patent Office: 963 Days
• Field of Search: 324/663, 324/664, 324/667, 324/671, 324/686, 324/689, 324/690, 324/693, 324/694, 324/695, 324/696, 324/699, 324/701, 324/717, 324/722, 324/724, 324/71.1, 73/53.03, 73/73, 73/74, 73/865, 340/604, 340/613, 361/282, 361/284, 162/198, 162/263
• US Class Current: 324/693
• CPC Class Codes: D21H 23/08 by measuring pulp properties, e.g. zeta potential, pH
• CPC Class Codes: G01G 9/00 Methods of, or apparatus for, the determination of weight, not provided for in groups G01G1/00 - G01G7/00
• CPC Class Codes: G01N 33/343 Paper pulp

Abstract

A measurement apparatus for sensing three properties of materials including a fixed impedance element coupled in series with the sensor array between an input signal and a reference potential (e.g. ground). The sensor array of the apparatus is an electrode configuration which includes a first elongated electrode coupled to the reference potential and second and third segmented elongated electrodes being parallel to and essentially in the same plane as the first elongated electrode. The segments within the second and third electrodes are configured such that the segments in the second electrode are staggered with respect to segments in the third electrode thereby minimizing or eliminating spacing between detection cells within the sensor array, reducing overall size of the sensor array and increasing measurement resolution. The sensor array exhibits a variable impedance resulting from changes in physical characteristics of the material. The variable impedance of the sensor array relates to changes in property of the material being sensed which can then be related to changes in other physical characteristics of the material such as weight, chemical composition, and temperature. The reduced size and increased resolution of the sensor array is particularly adaptive to a twin mesh sheetmaking system.

Claims

1. A sensor array in a measurement apparatus for detecting properties of a material, said measurement apparatus including a fixed impedance portion which is coupled to said sensor array, said fixed impedance portion and sensor array being coupled between a signal source and a reference potential, said sensor array having a variable impedance such that changes in properties of said material causes changes in the impedance of said sensor array, said sensor array comprising:

a first elongated electrode coupled to said reference potential;

second and third elongated segmented electrodes parallel and adjacent to said first elongated electrode, wherein segments within said second and third electrodes are configured with respect to each other such that segments in said second electrode are staggered with respect to segments in said third electrode;

wherein said material resides between and in close proximity to said first elongated electrode and said second and third segmented elongated electrodes and said changes in properties are detected by said first electrode and said second and third electrodes of said sensor array.

2. The sensor array as described in claim 1 wherein said second and third electrodes are coupled to said fixed impedance portion.

3. The sensor array as described in claim 2 wherein said fixed impedance portion comprises a plurality of resistive elements and each of said segments within said second and third electrodes are each coupled to one of said plurality of resistive elements.

4. The sensor array as described in claims 2 or 3 further including fourth and fifth electrodes coupled to said reference potential being spaced-apart and residing adjacent to said second and third electrodes.

5. The sensor array as described in claim 1 wherein said properties include dielectric constant, conductivity, and proximity of said material to said sensor.

6. The sensor array as described in claim 1 wherein said fixed impedance portion is one of an inductive element, capacitive element, and combinations of resistive, capacitive, and inductive elements each having an associated impedance and said signal source has an associated frequency and wherein said associated impedance of said one of said inductive element, capacitive element, and said combinations of elements is set to a particular magnitude by adjusting said signal source'"'"'s associated frequency to a given magnitude.

7. The sensor array as described in claim 6 wherein said signal source'"'"'s associated frequency is adjusted such that said impedance of said sensor array and said impedance of said one of said capacitive element, said inductive element, and said combination of elements are approximately equal.

8. The sensor array as described in claim 1 wherein said segments have a shape other than one of a rectangular and square shape and wherein said shape facilitates obtaining a greater average space between adjacent segments in each of said second and third electrodes.

9. A measurement apparatus for detecting properties of a material comprising:

a fixed impedance portion;

a sensor array coupled to said fixed impedance portion, said sensor array and said fixed impedance portion being coupled between a signal source and a reference potential, said sensor array having a variable impedance such that changes in properties of said material causes changes in the impedance of said sensor array, said sensor array comprising;

a first elongated electrode coupled to said reference potential and second and third elongated segmented electrodes parallel and adjacent to said first elongated electrode, wherein segments within said second and third electrodes are configured with respect to each other such that segments in said second electrode are staggered with respect to segments in said third electrode.

10. The apparatus as described in claim 9 wherein said second and third electrodes are coupled to said fixed impedance portion.

11. The apparatus as described in claim 10 wherein said fixed impedance portion comprises a plurality of resistive elements and each of said segments within said second and third electrodes are each coupled to one of said plurality of resistive elements.

12. The apparatus as described in claim 10 or 11 further including fourth and fifth electrodes coupled to said reference potential being spaced-apart and residing adjacent to said second and third electrodes.

13. The apparatus as described in claim 9 wherein said properties include dielectric constant, conductivity, and proximity of said material to said first electrode and said second and third electrodes of said sensor array.

14. The apparatus as described in claim 13 wherein said apparatus further comprises a means for correlating said changes in said properties to fluctuations in physical characteristics of said material including material weight, chemical composition, and temperature.

15. The apparatus as described in claim 9 wherein said fixed impedance portion is one of an inductive element, capacitive element, and combinations of resistive, capacitive, and inductive elements each having an associated impedance and said signal source has an associated frequency and wherein said associated impedance of said one of said inductive element, said capacitive element, and said combinations of elements is set to a particular magnitude by adjusting said signal source'"'"'s associated frequency to a given magnitude.

16. The apparatus as described in claim 15 wherein said signal source'"'"'s associated frequency is adjusted such that said impedance of said sensor array and said impedance of said one of said capacitive element, said inductive element, and said combination of elements are approximately equal.

17. The measurement apparatus as described in claim 9 wherein said segments have a shape other than one of a rectangular and square shape and wherein said shape facilitates obtaining a greater average space between adjacent segments in each of said second and third electrodes.