Flow balancing devices, methods, and systems

Patent metadata

Field	Value
Publication number	US-10869958-B2
Application number	US-201916381363-A
Country	US
Kind code	B2
Filing date	Apr 11, 2019
Priority date	Oct 10, 2014
Publication date	Dec 22, 2020
Grant date	Dec 22, 2020

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. A medical treatment method, comprising:
at treatment times, flowing medicament into and out of inflow and outflow channels connectable to a patient or to a treatment device with at least a first peristaltic pump and a second peristaltic pump;
at calibration times, over a calibration interval of less than a minute, flowing the medicament through a bridge channel between the inflow and outflow channels such that pulsations generated by the first peristaltic pump and the second peristaltic pump generate pressure fluctuations in the bridge channel, wherein the pressure fluctuations are caused by a superposition of a suction side pulsation of the first peristaltic pump and a pressure side pulsation of the second peristaltic pump; and
adjusting flow resistance in a pumping tube of at least one of the first peristaltic pump and the second peristaltic pump using an adjustable flow restrictor to generate a suction head of at least one of the first peristaltic pump and the second peristaltic pump so as to change a pulsation frequency of the respective peristaltic pump so that the changed pulsation frequency differs from the pulsation frequency of the other peristaltic pump by a predetermined amount.

2. The method of claim 1 , wherein the predetermined amount is such that a ratio of an inverse of a difference between pulsation frequencies of the first peristaltic pump and the second peristaltic pump is multiple times the calibration interval.

3. The method of claim 1 , wherein the predetermined amount is such that a ratio of an inverse of a difference between pulsation frequencies of the first peristaltic pump and the second peristaltic pump is three times the calibration interval.

4. The method of claim 1 , wherein the predetermined amount is such that a ratio of an inverse of a difference between pulsation frequencies of the first peristaltic pump and the second peristaltic pump is five times the calibration interval.

5. The method of claim 1 , wherein the predetermined amount is such that a ratio of an inverse of a difference between pulsation frequencies of the first peristaltic pump and the second peristaltic pump is eight times the calibration interval.

6. The method of claim 1 , wherein the predetermined amount is such that a ratio of an inverse of a difference between pulsation frequencies of the first peristaltic pump and the second peristaltic pump is twelve times the calibration interval.

7. A flow system, comprising:
a first peristaltic pump having rotors engaged with a first pumping tube segment and configured to pump fluid through the first pumping tube segment when the first peristaltic pump operates;
a second peristaltic pump having rotors engaged with a second pumping tube segment and configured to pump fluid through the second pumping tube segment when the second peristaltic pump operates;
a channel with a component fluidly connecting the first pumping tube segment to the second pumping tube segment and permitting a net flow into and out of the channel between the first and second peristaltic pumps, wherein
the first pumping tube segment has a different cross-sectional area than the second pumping tube segment,
when the first and second peristaltic pumps are pumping at equal flow rates, their rotational speeds are different,
the first peristaltic pump has a first pulsation frequency,
the second peristaltic pump has a second pulsation frequency,
superposition of the first pulsation frequency and the second pulsation frequency causes pressure fluctuations in the channel,
an adjustable flow restrictor is provided on at least one of the first pumping tube segment and the second pumping tube segment, and
the adjustable flow restrictor is adjusted to restrict flow and thereby cause the first pulsation frequency to differ from the second pulsation frequency by a predetermined amount.

8. The system of claim 7 , wherein the component includes a dialyzer.

9. The system of claim 7 , wherein the fluid is incompressible.

10. The system of claim 7 , wherein the first and second peristaltic pumps are interconnected by a fluid circuit that lacks a pulsation damper.

Assignees

• Nxstage Medical Inc

Inventors

• Burbank Jeffrey H
• Treu Dennis M
• Rubery Jr Daniel J
• Newell Scott W
• Brugger James M
• Schnell William J
• Weigel William K
• White Steven A
• Wyeth Mark T
• James Jerome
• Desouza David
• Turk Jr Joseph E
• Casey Garrett

Classifications

• A61M1/3607

  Regulation parameters · CPC title

• A61M1/34

  Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration · CPC title

• A61M1/3448

  by mechanically linked pumps in both ultra-filtrate and substitution flow line · CPC title

• A61M1/3437

  downstream of the filter, e.g. post-dilution with filtrate · CPC title

• A61M2205/058

  with ultrasound therapy · CPC title