Patent EP0302727A2 successfully refreshed from Google Patents.
EP0302727A2
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EP
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Monitoring apparatus
Assignee: Laetus Systems Ltd
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Filing: 1988-08-04
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Granted: —
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Expires: 2008-08-04
Abstract
Abstract Apparatus for monitoring the dielectric composition of articles, particularly articles such as blisterpacks and laminated boards. The apparatus comprises an amplifying circuit including a capacitor between the electrodes (1, 3) of which an article (22) is moved in use. The gain of the amplifying circuit varies with the capacitance of the capacitor so that the amplifying circuit provides an output signal, the peak value of the output signal varying with the dielectric constant of the article (22) between the capacitor electrodes (1, 3) . Typically the amplifying circuit includes an operational amplifier (9) the non-inverting input (10) of which is connected to a ground potential(6) and the inverting input (8) is connected to one electrode (3) of the capacitor. A feedback loop (11) is applied between the output (14) of the operational amplifier (9) and the inverting input (8) of the operational amplifier to force the inverting input to the same potential as the non-inverting input. Typically an oscillating signal source (5) is connected to the other electrode (1) of the capacitor.
Inventors
- 👤 Brian Robert Pullan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 06:58
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/24
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
67 words
Monitoring apparatus comprising an amplifying circuit including a capacitor between the electrodes (1, 3) of which an article (22) is moved in use and in which the gain of the amplifying circuit varies with the capacitance of the capacitor so that the peak value of the output signal of the amplifying circuit varies with the dielectric constant of the article (22) between the capacitor electrodes (1, 3).
Claim 2
Dependent Claim
67 words
Monitoring apparatus comprising an amplifying circuit including a capacitor between the electrodes (1, 3) of which an article (22) is moved in use and in which the gain of the amplifying circuit varies with the capacitance of the capacitor so that the peak value of the output signal of the amplifying circuit varies with the dielectric constant of the article (22) between the capacitor electrodes (1, 3).
Claim 3
Dependent Claim
45 words
Apparatus according to claim 1, wherein the amplifying circuit further comprises an operational amplifier (9) with the non-inverting input (10) of the operational amplifier (9) connected to a constant electrical potential (6) and the inverting input (8) connected to one electrode (3) of the capacitor.
Claim 4
Dependent Claim
15 words
Monitoring apparatus according to claim 2, wherein the constant electrical potential (6) is ground potential.
Claim 5
Dependent Claim
35 words
Apparatus according to claim 2 or claim 3, wherein the electrode (1) of the capacitor not connected to the inverting input (8) of the operational amplifier (9) is connected to an oscillating signal source (5).
Claim 6
Dependent Claim
37 words
Apparatus according to claim 4, wherein the capacitor electrode (1) connected to the oscillating signal source (5) comprises a conducting layer (25) formed on the opposite side of the article (22) from the other capacitor electrode (3).
Claim 7
Dependent Claim
53 words
Apparatus according to any of claims 2 to 5, further comprising a feedback loop (11) connected between the output (14) of the operational amplifier (9) and the inverting input (8) of the operational amplifier (9) whereby the inverting input (8) is forced to substantially the same potential as the constant electrical potential (6).
Claim 8
Dependent Claim
36 words
Apparatus according to any of the preceding claims, further comprising a peak detecting circuit (15) which receives output signals from the amplifying circuit and outputs the peak values of the signals received from the amplifying circuit.
Claim 9
Dependent Claim
37 words
Apparatus according to any of the preceding claims, further comprising a processing unit (21) for processing output signals from the amplifying circuit and a display device (24) to display the signals processed by the processing unit (21).
Claim 10
Dependent Claim
46 words
Apparatus according to any of the preceding claims, wherein one amplifying circuit is provided which scans across the article (22) transverse to the direction of motion of the article in use to produce signals which are then sequentially fed to the processing unit before being displayed.
Claim 11
Dependent Claim
49 words
Apparatus according to any of claims 1 to 8, wherein there is a plurality of amplifying circuits, each having substantially the same gain when the capacitance of each of the respective capacitors is substantially equal; and a multiplexer (19) to which output signals from the amplifying circuits are sent.
Claim 12
Dependent Claim
26 words
Apparatus according to claim 10, wherein the respective capacitors are positioned in a line transverse to the direction of movement of the article (22) in use.
Claim 13
Dependent Claim
27 words
Apparatus according to claim 10 or claim 11, when dependant on at least claim 2, the constant electrical potential (6) for each amplifying circuit being substantially equal.
Claim 14
Dependent Claim
22 words
Apparatus according to any of claims 10 to 12, wherein one set of respective capacitor electrodes (1) form a single, continuous electrode.
Claim 15
Dependent Claim
58 words
Apparatus according to any of claims 2 to 13, the apparatus further comprising a guard electrode (4) in close proximity to the capacitor electrode (3) connected to the inverting input (8) of the operational amplifier (9), wherein the guard electrode (4) is at substantially the same constant potential (6) as the non-inverting input (10) of the operational amplifier.
Claim 16
Dependent Claim
22 words
Apparatus according to any of the preceding claims, wherein one electrode (3) of the capacitor is a matrix of electrode pads (31).
References Cited (Backward Citations)
No citation records indexed.
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