Remote conductivity sensor using square wave excitation
First Claim
1. Apparatus for remotely sensing conductivity of a fluid passing through it, said apparatus comprisinga cell including means for defining a fluid flow path having a fluid loop and excitation and sensing transformers each having a core encompassing a portion of said fluid loop, anda digital timer and a flip-flop connected to provide a square wave excitation signal to said excitation transformer.
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Accused Products
Abstract
A liquid conductivity sensor which features simply and inexpensively driving the excitation transformer of a two-transformer/fluid-loop remote conductivity sensor with a square wave excitation signal provided by a digital timer and a flip-flop. Also disclosed is using an electrodeless conductivity sensor to sense conductivity of dialysate.
96 Citations
10 Claims
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1. Apparatus for remotely sensing conductivity of a fluid passing through it, said apparatus comprising
a cell including means for defining a fluid flow path having a fluid loop and excitation and sensing transformers each having a core encompassing a portion of said fluid loop, and a digital timer and a flip-flop connected to provide a square wave excitation signal to said excitation transformer.
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9. Dialysate preparation and supply apparatus comprising
a dialysate supply line, fluid flow path means for defining a fluid flow path in said supply line, said means having an inlet and an outlet and two fluid paths between the two, thereby defining a fluid loop, an excitation transformer comprising a first toroidal core having a hole through it and wire turns around it, said core encompassing a portion of said fluid flow path means and said fluid loop therein, a sensing transformer comprising a second toroidal core having a hole through it and wire turns around it, said core encompassing a portion of said fluid flow path means and said fluid loop therein, and a digital timer and a flip-flop connected to provide a square wave excitation signal to said excitation transformer.
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10. Dialysate preparation and supply apparatus comprising
a dialysate supply line, fluid flow path means for defining a fluid flow path in said supply line, said means having an inlet and an outlet and two fluid paths between the two, thereby defining a fluid loop. an excitation transformer comprising a first core having a hole through it and wire turns around it, said core encompassing a portion of said fluid flow path means and said fluid loop therein, a sensing transformer comprising a second core having a hole through it and wire turns around it, said core encompassing a portion of said fluid flow path means and said fluid loop therein, and a digital timer and a flip-flop connected to provide a square wave excitation signal to said excitation transformer.
Specification
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- Resources
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Current AssigneeGambro, Inc. (DaVita Incorporated)
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Original AssigneeCobe Cardiovascular Incorporated (LivaNova Plc)
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InventorsEilers, George J., Lobdell, Donn D., Ogawa, Francis T., Manes, Michael R., Boucher, Terry D.
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Primary Examiner(s)Eisenzopf, Reinhard J.
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Assistant Examiner(s)Harvey, Jack B.
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Application NumberUS06/869,087Time in Patent Office1,061 DaysField of Search324/439, 324/442, 324/445, 324/446, 324/450, 324/204, 204/17, 204/400, 204/406US Class Current324/439CPC Class CodesA61M 1/1607 before use, i.e. upstream o...G01N 27/023 where the material is place...
