Fluid property measurement devices, methods, and systems

Patent metadata

Field	Value
Publication number	US-12078549-B2
Application number	US-202017002207-A
Country	US
Kind code	B2
Filing date	Aug 25, 2020
Priority date	Jul 25, 2012
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

A system for measuring electrical conductivity includes a fluid conduction measuring circuit and a temperature measuring element having at least one thermal contact portion with a temperature sensor and a temperature measuring circuit. A controller is configured to control the conduction measuring circuit and the temperature measuring element. A fluid circuit is configured to carry a fluid and has a wetted conductor inside a conductivity cell portion, the wetted conductor having a contact, external to the fluid circuit, for interfacing with the fluid conduction measuring circuit. Further, at least one temperature measurement portion has predefined thermal properties and is configured to touch the thermal contact portion. The controller controls the temperature measuring element and the conduction measuring circuit to generate and output at least one set of contemporaneous temperature and conduction measurements.

First claim

What is claimed is:

1. A system for measuring electrical conductivity of a fluid flowing in a fluid circuit, the system comprising:
a measuring circuit configured to measure a conduction or an electrical resistance of the fluid in the fluid circuit;
a temperature measuring element having at least one thermal contact with a temperature sensor and a temperature measuring circuit;
a controller configured to control said measuring circuit and said temperature measuring element; and
the fluid circuit configured to carry the fluid, said fluid circuit including
one or more capacitive and/or inductive coupling portions that permit resistance measurement of the fluid inside a resistivity cell portion of the fluid circuit through a wall of the fluid circuit; and
at least one temperature measurement region having predefined thermal properties and configured to physically touch said at least one thermal contact, wherein

said controller is configured to control said temperature measuring element and said measuring circuit to generate and output at least one set of contemporaneous temperature and conduction measurements, and
said temperature measuring element includes an active temperature regulator configured to apply heat to or draw heat from said thermal contact and said controller is configured to regulate said active temperature regulator so as to nullify heat flow through a wall of said temperature measurement region in physical contact with the thermal contact.

2. The system of claim 1 , wherein the controller is configured to derive a fluid property algorithm or populate a database responsively to said contemporaneous temperature and conduction measurements.

3. The system of claim 1 , wherein the controller is configured to regulate a heat flux rate through said temperature measurement region responsively to a temperature indication signal from said temperature sensor such that the temperature indication signal represents a temperature of the fluid on a side of a wall of the fluid circuit opposite said temperature sensor.

4. The system of claim 1 , wherein said one or more capacitive and/or induction coupling portions are connected to a resistance measurement circuit, measuring resistance through the capacitive and/or induction coupling portions and interfacing with said measuring circuit.

5. The system of claim 4 , wherein
the fluid circuit includes the one or more capacitive coupling portions.

6. The system of claim 5 , wherein the controller is configured to derive a fluid property algorithm or database responsively to said contemporaneous temperature and resistance measurements.

7. The system of claim 1 , wherein
the fluid circuit further includes a wetted conductor inside a conductivity cell portion.

8. The system of claim 7 , wherein the controller is configured to derive a fluid property algorithm or populate a database responsively to said contemporaneous temperature and conduction measurements.

9. The system of claim 7 , wherein the controller is configured to regulate a heat flux rate through said temperature measurement region responsively to a temperature indication signal from said temperature sensor such that the temperature indication signal represents a temperature of the fluid on a side of a wall of the fluid circuit opposite said temperature sensor.

10. The system of claim 7 , wherein said one or more capacitive and/or induction coupling portions are connected to a resistance measurement circuit, measuring resistance through the capacitive and/or induction coupling portions and interfacing with said measuring circuit.

Assignees

• Nxstage Medical Inc

Inventors

• Newell Scott W
• Kogan Yakov

Classifications

• G01K7/16

  using resistive elements · CPC title

• G01R27/22

  Measuring resistance of fluids · CPC title

• G01K13/026

  of moving liquids · CPC title

• G05D11/135

  by sensing at least one property of the mixture (G05D11/139 takes precedence) · CPC title

• G05D11/16

  Controlling mixing ratio of fluids having different temperatures, e.g. by sensing the temperature of a mixture of fluids having different viscosities · CPC title