Liquid level sensor including conductive plastic technology
AssigneeSpectrol Electronics Corporation
InventorsRichard E. Riley, Thomas H. Brunjes
Life of this patent
Estimating the term…
Abstract
A liquid level sensor for sensing liquid levels within a container is disclosed. The sensor includes a conductive plastic resistor and conductive plastic conductors deposited onto a thin polymer insulator. The conductive plastic resistor is a potentiometric resistive track which is electrically contacted at points along the length of the resistor by a contact assembly attached to a float. The polymer insulator is attached to a conductive support member or conductive strip disposed substantially vertically in the liquid. The float is disposed about the conductive strip. The contacts provide a short circuit between the resistive strip and conductive strip and thereby provide a resistive circuit connection analogous to the wiper of a potentiometer.
Claims18
A liquid level sensor for providing a variable resistance corresponding to fluid level in a container, said sensor comprising:
- an elongated conductive support member having at least one elongated planar surface;
- an insulating film attached to and substantially covering said planar surface of said conductive member;
- a resistive strip having a first and a second end, said resistive strip attached to said insulating film, said resistive strip substantially aligned with the longitudinal axis of said conductive member;
- a first conductive strip attached to said insulator, said conductive strip disposed substantially in parallel with said resistive strip, said conductive strip having a length substantially equal to the length of said resistive strip, said first conductive strip electrically connected to said first end of said resistive strip;
- a second conductive strip attached to said insulator and electrically connected to said second end of said resistive strip;
- a float having a hole for axially receiving said conductive member wherein said float is positioned according to the liquid level in the container;
- and
- electrical contact means attached to said float for continuously establishing an electrical connection between said resistive strip and said conductive member.
A liquid level sensor for providing a variable resistance corresponding to fluid level in a container, said sensor comprising:
- a conductive rod having a first end and a second end;
- an insulating film attached to said conductive rod on the lateral surface of said rod;
- a resistive strip having a first and a second end, said resistive strip attached to said insulating film, said resistive strip substantially aligned with the longitudinal axis of said conductive rod;
- a first conductive strip attached to said insulator, said conductive strip disposed substantially in parallel with said resistive strip, said conductive strip having a length substantially equal to the length of said resistive strip, said first conductive strip electrically connected to said first end of said resistive strip;
- a second conductive strip attached to said insulator and electrically connected to said second end of said resistive strip;
- a float having a hole for axially receiving said conductive rod wherein said float is positioned according to the liquid level in the container;
- and
- electrical contact means attached to said float for continuously establishing an electrical connection between said resistive strip and said conductive rod.
Dependencies are inferred from the claim text.