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John D Sotack, William L Dezen, Lawrence R Benedict, Gaith O Zayed, Alan J Werner Jr: Capacitive sensor. Xerox Corporation, John S Wagley, November 14, 1995: US05465619 (131 worldwide citation)

An apparatus for detecting the level of material in a container. The apparatus comprises a power source and a first electrode, positioned adjacent the container, electrically connected to the power source. The apparatus further comprises a second electrode. The second electrode is spaced from the fi ...


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Robert Pelovitz: Method and apparatus for sensing liquid level using baseline characteristic. Keurig Incorporated, Wolf Greenfield & Sacks P C, April 22, 2008: US07360418 (75 worldwide citation)

A liquid level sensing arrangement using a probe uses a baseline probe circuit characteristic, e.g., a circuit resistance or voltage, that is measured when the probe is out of contact with the liquid in the tank. The baseline characteristic may be used to determine a liquid level in the tank, e.g., ...


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Brian Lauman, Pete Hopping, Rick Kienman, Shahid Din, Robert W Childers: Capacitance fluid volume measurement. Baxter International, Baxter Healthcare, Joseph P Reagen, Bell Boyd & Lloyd, September 19, 2006: US07107837 (72 worldwide citation)

A fluid volumetric pumping system has a fluid pump and capacitor plates disposed around a pump chamber of the fluid pump. The capacitance between the capacitor plates changes as the volume of fluid in the pump chamber changes. An electrical circuit measures a change in the capacitance between the pl ...


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Kim W Atherton, Charles R Clow, Patrick H Mawet: Dielectric liquid level sensor and method. Caterpillar, Robert E Muir, February 21, 1989: US04806847 (72 worldwide citation)

A sensor for sensing the level of oil or transmission fluid under both normal and extreme temperature conditions. The only active components of the sensor have input and leakage currents substantially lower than those of diodes and current sources under high temperature conditions. The sensor has a ...


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Gary C Causley, Martin D Rosback: Ink cartridge with ink level sensor. Tektronix, John D Winkelman, David P Peterson, November 5, 1985: US04551734 (69 worldwide citation)

An ink cartridge 10 includes an ink level sensor 38 having a probe supporting structure, such as platform 174, which projects into a collapsible ink container 16 from an ink container support 18. First and second electrical probes 40, 41 are embedded within the structure, with tip portions 188, 190 ...


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Yishay Netzer: Compensated capacitive liquid level sensor. Millennium Sensors, Mark M Friedman, December 10, 2002: US06490920 (66 worldwide citation)

A fringing-field capacitive liquid level sensor comprising an electrically insulating substrate, having a first and a second pattern of conductive capacitance plates plated on the substrate. Each pattern constitutes a fringing-field capacitor having a capacitance the value of which is both dependent ...


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Ronald A Zweifel: Capacitive sensing system and technique. Packard Instrument Company, Arnold White & Durkee, November 22, 1994: US05365783 (65 worldwide citation)

An arrangement senses a liquid level by monitoring the peak capacitance formed between a probe and the liquid as the probe approaches or departs from the liquid. In an automated system, a computer controls the position of a pipette probe for aspirating or dispensing liquid in the vessel. The charge ...


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Maltby Frederick L: Probe responsive to conditions of material. Drexelbrook Controls, Woodcock Washburn Kurtz & Mackiewicz, April 22, 1975: US3879644 (52 worldwide citation)

In an RF system which measures the level of materials, the probe includes a measuring electrode and a guard shield. The guard shield is interposed between the electrode and a conductive member, commonly the container for the material, throughout the body of the probe.


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Maltby Frederick L, Kramer Jonathan: Continuous condition measuring system. Drexelbrook Controls, December 25, 1973: US3781672 (52 worldwide citation)

In a system which continuously measures the composition, position or size of materials, the probe has a guard shield which is effective for continuous measurement. The measurement system includes a zero adjusting impedance connected with the variable probe impedance as two adjacent arms of a balance ...