Flow balancing devices, methods, and systems

Patent metadata

Field	Value
Publication number	US-10898635-B2
Application number	US-201716317903-A
Country	US
Kind code	B2
Filing date	Jul 18, 2017
Priority date	Jul 18, 2016
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

The disclosed subject matter relates to extracorporeal blood processing or other processing of fluids. Volumetric fluid balance, a required element of many such processes, may be achieved with multiple pumps or other proportioning or balancing devices which are to some extent independent of each other. This need may arise in treatments that involve multiple fluids. Safe and secure mechanisms to ensure fluid balance in such systems are described.

First claim

The invention claimed is:

1. An apparatus for controlling flow in a fluid circuit, comprising:
a treatment machine with flow regulators and sensors, the flow regulators including pumping actuators;
the treatment machine having a controller connected to control the flow regulators and receive signals from the sensors to implement a therapeutic treatment by regulating a flow of blood and treatment fluid when a predefined fluid circuit is connected in operative engagement with said flow regulators and sensors;
where the predefined fluid circuit has a plurality of fluid lines including first fluid lines and second fluid lines and other fluid lines all interconnected by the fluid circuit, each of the fluid lines being used to transport a fluid during a treatment mode in order to implement said therapeutic treatment;
the flow regulators being controlled by said controller, during a synchronization mode thereof, to selectively block flow in first ones of said fluid lines while selectively pumping fluid serially through second ones of said fluid lines such that first and second pumping actuators pump fluid in a fixed volume channel that interconnects the second ones of said fluid lines, the fixed volume channel being sealed in part by said first ones of said fluid lines;
the controller, during said synchronization mode, regulating relative speeds of the first and second pumping actuators responsively to at least one of the sensors to estimate commanded rates of said first and second pumping actuators corresponding to equal flows throughout said fixed volume channel and deriving one or more control parameters permitting said controller to implement a predefined ratio of flow rates by said first and second pumping actuators during a treatment mode of said controller;
the flow regulators being controlled by said controller to, during the treatment mode, regulate a net flow through said second ones of said fluid lines by commanding the relative speeds of the first pumping actuator responsively to said one or more control parameters.

2. The apparatus of claim 1 , wherein some of the first and second fluid lines are interconnected by a treatment device.

3. The apparatus of claim 2 , wherein the treatment device is a dialyzer and said second fluid lines are fresh dialysate and waste dialysate lines, respectively.

4. The apparatus of claim 1 , wherein the first and second fluid lines are interconnected by a treatment device, the second fluid lines are blood lines and said first and second pumping actuators are fresh and waste treatment fluid blood pumping actuators.

5. The apparatus of claim 1 , wherein, during the synchronization mode, the first and second pumping actuators are operated at multiple speeds to generate multiple of the one or more control parameters by regulating relative speeds of the first and second pumping actuators to achieve equal flows of multiple magnitudes.

6. The apparatus of claim 5 , wherein the sensors include pressure sensors.

7. The apparatus of claim 6 , wherein pressure data corresponding to pressure signals from the pressure sensors are recorded during said synchronization mode and included in said one or more control parameters, the pressure signals being used by the controller to generate a commanded speed of at least one of said first and second pumping actuators to account for differences between said pressure data and pressure signals during said synchronization mode and said treatment mode.

8. The apparatus of claim 1 , wherein the sensors include a weight sensor, said controller determining equal flows in said second fluid lines from said weight sensor.

9. The apparatus of claim 8 , wherein the controller determines equal flows in said second fluid lines from a state where weight indicated by said weight sensor is unchanging.

10. The apparatus of claim 1 , wherein the sensors include a pressure sensor, said controller determining equal flows in said second fluid lines from said pressure sensor.

11. The apparatus of claim 10 , wherein the controller determines equal flows in said second fluid lines from a state where pressure indicated by said pressure sensor is unchanging.

12. The apparatus of claim 1 , wherein said flow regulators include at least one control valve that engages with one of said first fluid lines.

13. The apparatus of claim 12 , wherein said flow regulators include a third pumping actuator that engages with one of said first fluid lines, said third pumping actuator being halted during said synchronization mode to prevent flow in said one of said first fluid lines.

14. The apparatus of claim 1 , wherein the controller establishes said equal flows throughout said fixed volume channel for a predefined interval.

15. The apparatus of claim 1 , wherein, during said synchronization mode, said controller directly measures a flow rate generated by at least one of said first and second pumping actuators to generate a flow rate parameter, said one or more control parameters including data responsive to said flow rate parameter.

16. The apparatus of claim 1 , wherein the first fluid lines engage third and fourth pumping actuators, respectively, said third and fourth pumping actuators being halted during said synchronization mode to prevent flow in said one of said first fluid lines.

Assignees

• Nxstage Medical Inc

Inventors

• Desouza David
• Rubery Jr Daniel J
• Treu Dennis M
• Wyeth Mark T
• James Jerome
• Casey Garrett D
• Brugger James M
• Schnell William J
• Burbank Jeffrey H
• Friederichs Goetz

Classifications

• A61M2205/3393

  by weighing the reservoir · CPC title

• A61M2205/3331

  Pressure; Flow · CPC title

• A61M1/1647 Primary

  with flow rate measurement of the dialysis fluid, upstream and downstream of the dialyser · CPC title

• A61M2205/3334

  Measuring or controlling the flow rate · CPC title

• A61M2205/50

  with microprocessors or computers · CPC title