Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
87 words
A level sensor for sensing the level of a flowable material, the sensor comprising: a single circuit for measuring capacitance; exactly two electrodes, comprising a return electrode and a measuring probe, wherein the measuring probe comprises: at least two, electrically-common, level-detecting formations, each of the formations arranged substantially parallel to a free surface of the flowable material, whereby two step rises in the capacitance are measurable by the circuit as the flowable material rises past first one of the formations and then the other of the formations.
Claim 2
Dependent Claim
87 words
A level sensor for sensing the level of a flowable material, the sensor comprising: a single circuit for measuring capacitance; exactly two electrodes, comprising a return electrode and a measuring probe, wherein the measuring probe comprises: at least two, electrically-common, level-detecting formations, each of the formations arranged substantially parallel to a free surface of the flowable material, whereby two step rises in the capacitance are measurable by the circuit as the flowable material rises past first one of the formations and then the other of the formations.
Claim 3
Dependent Claim
16 words
A level sensor as claimed in claim 1 , wherein the flowable material is a liquid.
Claim 4
Dependent Claim
19 words
The level sensor of claim 1 , wherein the return electrode is a discrete probe adjacent the flowable material.
Claim 5
Dependent Claim
27 words
The level sensor of claim 1 , wherein the return electrode is earth, and the circuit for measuring capacitance comprises a circuit for measuring capacitance to earth.
Claim 6
Dependent Claim
22 words
A level sensor as claimed in claim 1 , wherein the two formations are discrete probe elements which are electrically connected together.
Claim 7
Dependent Claim
22 words
A level sensor as claimed in claim 5 , wherein discrete probe elements are configured as strips external to a non-metallic vessel.
Claim 8
Dependent Claim
20 words
The level sensor of claim 3 , wherein the formations are disposed in the flowable material, the formations being coaxial.
Claim 9
Dependent Claim
23 words
A level sensor as claimed in claim 1 , wherein the two formations are formed or joined together on a single probe stem.
Claim 10
Dependent Claim
35 words
The level sensor of claim 8 , wherein the second formation is disposed above the first formation and the second formation has a capacitive surface area at least three times that of the first formation.
Claim 11
Dependent Claim
23 words
A level sensor as claimed in claim 8 , wherein the formations are of wire formed into spirals extending transversely of a stem.
Claim 12
Dependent Claim
14 words
A level sensor as claimed in claim 1 , wherein the probes are insulated.
Claim 13
Dependent Claim
34 words
A level sensor as claimed in claim 1 , wherein the measuring probe has three or more formations, with the measuring means being adapted to indicate in accordance with a corresponding plurality of levels.
Claim 14
Dependent Claim
61 words
The level sensor of claim 1 , wherein the circuit for measuring capacitance comprises: means for measuring the capacitance between the pair of electrodes; and means for outputting a first signal if the capacitance is within a certain tolerance of a first threshold and for outputting a second signal if the capacitance is within a certain tolerance of a second threshold.
Claim 15
Dependent Claim
56 words
The level sensor of claim 13 further comprising: two counters and means for controlling the counters so that if neither threshold is reached; each counter is decremented; if just the first threshold is reached, the first counter is is incremented and the second counter is decremented; and if both thresholds are reached both counters are incremented.
Claim 16
Dependent Claim
17 words
The level sensor of claim 13 wherein the circuit for measuring capacitance is configured as a microchip.