Admittance sensing probe for measuring level

Claim 2

An admittance sensing probe adapted to sense the level of materials within a vessel comprising: a condition measuring probe electrode comprising a conductive material; a compensating probe electrode comprising a conductive material; a conductor connected to one of said electrodes; and conductive shield means interposed between said conductor and said other of said electrodes, said conductive shield means also being interposed between said conductor and said materials within said vessel. 4 GB

Claim 3

2 040 468 A 4 2. The admittance sensing probe of claim 1 wherein said conductive shield means is also interposed between said probe electrodes.

Claim 4

The admittance sensing probe of claim 2" wherein said conductive shield means extend beyond said one probe electrode in a direction away from said other probe electrode.

Claim 5

The admittance sensing probe of claim 1 wherein said probe is elongate and said composition probe electrode and said level measuring probe electrode are mutually longitudinally spaced along the probe.

Claim 6

The admittance sensing probe of claim 4 wherein said longitudinal length of said composition probe electrode is short relative to said measuring probe electrode.

Claim 7

The admittance sensing probe of claim 5 wherein said shield means and said conductor extend longitudinally along the probe. 20

Claim 8

The admittance sensing probe of claim 6 wherein said shield means is also physically interposed between said compensating probe electrode and said condition measuring probe electrode. 25

Claim 9

The admittance sensing probe of claim 7 wherein said shield means extends longitudinally beyond said compensating probe electrode.

Claim 10

The admittance sensing probe of claim 6 wherein said shield means is physically interposed between said compensating probe electrode and said condition measuring probe electrode and said shield means extend longitudinally beyond said compensating probe electrode.

Claim 11

The admittance sensing probe of claim 4 wherein: said compensating probe electrode is substantially cylindrical; said condition measuring probe electrode is substantially cylindrical; 40 said conductor extending through said condition measuring probe electrode and compensating probe electrode in a direction generally parallel with the axis of said condition measuring probe electrode; and 45 said shield means also extending through said 110 condition measuring probe electrode generally parallel with the axis of said condition measuring probe electrode.

Claim 12

The admittance sensing probe of claim 10 further comprising insulating means tightly covering said compensating probe electrode and said condition measuring probe electrode.

Claim 13

The admittance sensing probe of claim 11 wherein said insulating means comprises a high molecular weight polymer of vinylidene fluoride having a dielectric constant in excess of 4.

Claim 14

The admittance sensing probe of claim 12 further comprising a coaxial cable including an inner conductor and an outer conductor, said conductor comprising the inner conductor of said cable and said shield means comprising the outer conductor of said cable.

Claim 15

The admittance sensing probe of claim 13 wherein said shield means extends radiailly outwardly to a position between said compensating probe electrode and said condition measuring probe electrode.

Claim 16

The admittance sensing probe of claim 14 wherein said shield means extends beyond said compensating probe electrode away from said condition measuring electrode.

Claim 17

The admittance sensing probe of claim 1 including circuit means for combining the admittance measured at said condition measuring electrode with the admittance measured at said compensation probe with electrode for detecting the level of material corrected for variations in the nature of the material.

Claim 18

The admittance sensing probe of claim 1 wherein said shield means is driven at substantially the same potential as said condition measuring probe electrode and said compensating probe electrode.

Claim 19

The admittance sensing probe of claim 1 wherein said conductive shield means extends beyond said one probe electrode in a direction away from said other probe electrode and also extends beyond said other probe electrode in an opposing direction away from said one probe electrode and said other probe electrode.

Claim 20

The admittance sensing probe of claim 18 wherein said probe is elongate and said compensation probe electrode is located nearer one end and said condition measuring probe electrode is located nearer another end.

Claim 21

The admittance sensing probe of claim 19 wherein said shield means extends beyond said condition measuring probe electrode in said opposing direction.

Claim 22

2 1. The admittance sensing probe of claim 20 further comprising a coaxial cable having an inner conductor and an outer conductor wherein said shield means includes the outer conductor of a coaxial cable and the inner conductor is connected to said compensating probe electrode.

Claim 23

The admittance sensing probe of claim 21 including additional shield means connected to said outer conductor at said one end of said probe.

Claim 24

An elongated admittance sensing probe adapted to sense the level of materials within a vessel comprising: a condition measuring probe electrode comprising a conductive material nearer one end of said probe; a compensating probe electrode comprising a conductive material nearer another end of said probe; and a conductive shield means interposed between said condition measuring probe electrode and said compensating probe electrode.

Claim 25

An elongated admittance sensing probe adapted to sense the level of materials within a vessel comprising: a condition measuring probe electrode comprising a conductive material nearer one end of said probe; a compensating probe electrode comprising a conductive material nearer another end of said probe; and a conductive shield means interposed between said condition measuring probe electrode and said compensating probe electrode.

Claim 26

The admittance sensing probe of claim 23 further comprising additional conductive shield means located adjacent one end of said probe and longtitudinally displaced from said compensating probe electrode such that said compensating probe electrode is located between said additional shield means and said condition measuring probe electrode.

Claim 27

An elongated admittance sensing probe 1 GB 2 040 468 A 5 adapted to sense the level of materials within a vessel comprising: a condition measuring probe electrode comprising a conductive material; 5 a compensating probe electrode comprising a conductive material longitudinally displaced from said condition measuring probe electrode; and conductive shield means located adjacent one end of said probe and longitudinally displaced from said compensating probe electrode such that said compensating probe electrode is located between said shield means and said condition measuring probe ele ctrode.

Claim 28

An elongated admittance sensing probe 1 GB 2 040 468 A 5 adapted to sense the level of materials within a vessel comprising: a condition measuring probe electrode comprising a conductive material; 5 a compensating probe electrode comprising a conductive material longitudinally displaced from said condition measuring probe electrode; and conductive shield means located adjacent one end of said probe and longitudinally displaced from said compensating probe electrode such that said compensating probe electrode is located between said shield means and said condition measuring probe ele ctrode.

Claim 29

An admittance sensing probe substantially as herein described with reference to the drawings. Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980. Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

Claim 30

An admittance sensing probe substantially as herein described with reference to the drawings. Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980. Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.