Capacitance probe
First Claim
1. A proximity sensor apparatus comprising a capacitor and means for detecting the change in capacitance of the capacitor, said capacitor comprising two capacitive elements and insulation means, said elements being movable relative to each other and being insulated from each other by said insulation means, at least one of the capacitive elements being formed by an electrically conducting liquid, said apparatus further comprising an inner and outer container, the outer container being made from a suitable electrically non-conducting material, said inner container being fitted inside and substantially surrounded by said outer container, within said inner container being mounted the means for detecting the change in capacitance of the capacitor, on a part of the exterior of the said inner container one of the elements of the capacitor being affixed, the other capacitor element being disposed outside said outer container, the outer container thereby providing the insulation means between the two capacitive elements, the outer container also being of such dimensions and construction that a capacitor can be formed between the two said capacitor elements of the capacitor.
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Accused Products
Abstract
A proximity sensing apparatus comprising a capacitor and means for detecting the change in capacitance of the capacitor. The capacitor comprises two capacitive elements that are insulated from each other and are relatively movable. With at least one of the capacitive elements formed from an electrically conducting liquid. The capacitance detecting means operate as a switch in response to the change in capacitance producing a binary output. This output being combined with a series of other outputs from a series of such proximity sensors to form an apparatus to determine position of an object, particularly a liquid level.
23 Citations
12 Claims
- 1. A proximity sensor apparatus comprising a capacitor and means for detecting the change in capacitance of the capacitor, said capacitor comprising two capacitive elements and insulation means, said elements being movable relative to each other and being insulated from each other by said insulation means, at least one of the capacitive elements being formed by an electrically conducting liquid, said apparatus further comprising an inner and outer container, the outer container being made from a suitable electrically non-conducting material, said inner container being fitted inside and substantially surrounded by said outer container, within said inner container being mounted the means for detecting the change in capacitance of the capacitor, on a part of the exterior of the said inner container one of the elements of the capacitor being affixed, the other capacitor element being disposed outside said outer container, the outer container thereby providing the insulation means between the two capacitive elements, the outer container also being of such dimensions and construction that a capacitor can be formed between the two said capacitor elements of the capacitor.
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11. A proximity sensor apparatus comprising a capacitor and means for detecting the change in capacitance of the capacitor, said capacitor comprising two capacitive elements and insulation means, said elements being movable relative to each other and being insulated from each other by said insulation means, at least one of the capacitive elements being formed by an electrically conducting liquid, the other capacitive element forming a unit with said means for detecting, said other capacitive element and said means for detecting being associated with one another on a common support member to minimize the distance between them.
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12. A proximity sensor apparatus comprising a capacitor and means for detecting the change in capacitance of the capacitor, said capacitor comprising two capacitive elements and insulation means, said elements being movable relative to each other and being insulated from each other by said insulation means, at least one of the capacitive elements being formed by an electrically conducting liquid, said apparatus further comprising first and second spaced apart support members, the second support member being made from a suitable electrically non conducting material, said first support member being substantially surrounded by said second support member, said means for detecting the change in capacitance of the capacitor being mounted on said first support member, on a part of said first support member one of the elements of the capacitor being affixed, the other capacitive element being disposed on said second support member, said second support member thereby providing the insulation means between the two capacitive elements, the second support member also being of such dimensions and construction that a capacitor can be formed between the two said capacitive elements of the capacitor.
Specification