Fluid property measurement devices, methods, and systems

• US 10,760,974 B2
• Filed: 11/18/2017
• Issued: 09/01/2020
• Est. Priority Date: 07/25/2012
• Status: Active Grant

• Current Assignee: Nxstage Medical Incorporated (Fresenius Medical Care AG)
• Original Assignee: Nxstage Medical Incorporated (Fresenius Medical Care AG)
• Inventors: Newell, Scott W., Kogan, Yakov
• Primary Examiner(s): Murphy, Kevin F
• Application Number:
  US15/817,183
• Publication Number:
  US 20180128688A1
• Time in Patent Office: 1,018 Days
• CPC Class Codes: A61M 2205/3372 Temperature compensation
• CPC Class Codes: G01K 1/14 Supports; Fastening devices; Arrangements for mounting thermometers in particular locations
• CPC Class Codes: G01K 13/026 of moving liquids
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L
• CPC Class Codes: G01N 27/08 which is flowing continuously
• CPC Class Codes: G01R 27/22 Measuring resistance of fluids
• CPC Class Codes: G05D 11/135 by sensing at least one property of the mixture G05D11/139 takes precedence
• CPC Class Codes: G05D 11/138 by sensing the concentration of the mixture, e.g. measuring pH value
• CPC Class Codes: G05D 11/16 Controlling mixing ratio of fluids having different temperatures, e.g. by sensing the temperature of a mixture of fluids having different viscosities

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.

Claims

1. A system for generating a medicament, comprising:

a fluid circuit having a disposable portion;

a fluid conductivity measuring portion configured to measure a conductivity of a mixed product flowing through the disposable portion and to output a conductivity signal;

a temperature detecting device; and

a controller configured to receive at least a temperature signal from the temperature detecting device and a conductivity signal from the fluid conductivity measuring portion, wherein,

the disposable portion is connected to convey the mixed product,

the temperature detecting device is in contact with the disposable portion and adapted to measure a temperature of the mixed product and to output the temperature signal,

the controller is configured to control a relative flow of water and a concentrate responsively to both of said temperature and conductivity signals, and

the temperature detecting device includes

a first temperature sensor attached to a flat member that is adapted to be placed against a wall of the disposable portion,

a second temperature sensor separated from the first temperature sensor by a thermal insulator,

a temperature regulating device in thermal contact with the second temperature sensor and

a temperature controller configured to receive first and second temperature indication signals, respectively, from the first and second temperature sensors and to regulate said temperature regulating device responsively to the first and second temperature indication signals.

2. The system of claim 1, wherein the controller is configured for feedback control of a concentration of said mixed product.

3. The system of claim 1, wherein the controller is configured to calculate, or look up in a data store, a parameter dependent on a concentration of the mixed product and to employ it as a feedback control signal to regulate concentration of said mixed product.

4. The system of claim 1, wherein

the thermal insulator is an insulating air gap.

5. The system of claim 1, wherein

the thermal insulator includes multiple layers of materials.

6. The system of claim 5, wherein

the thermal insulator includes layers of high conductivity materials to promote transfer of heat in specific directions.