Peristaltic pulse pumping systems and methods

• US 5,538,405 A
• Filed: 07/01/1994
• Issued: 07/23/1996
• Est. Priority Date: 07/01/1994
• Status: Expired due to Term

• Current Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Baxter International Inc.
• Inventors: Brown, Richard I., Patno, Timothy J., Cork, William H.
• Primary Examiner(s): Korytnyk, Peter
• Application Number:
  US08/269,933
• Time in Patent Office: 753 Days
• Field of Search: 417/477.1, 417/326, 417/474, 417/476
• US Class Current: 417/326
• CPC Class Codes: A61M 1/30 Single needle dialysis ; Reciprocating systems, alternately withdrawing blood from and returning it to the patient, e.g. single-lumen-needle dialysis or single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 1/302 having a reservoir for withdrawn untreated blood
• CPC Class Codes: A61M 1/303 having a reservoir for treated blood to be returned
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/3693 using separation based on different densities of components, e.g. centrifuging
• CPC Class Codes: A61M 1/3696 with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: F04B 2203/0209 Rotational speed
• CPC Class Codes: F04B 43/0081 systems, control, safety measures
• CPC Class Codes: F04B 43/1253 by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing

Abstract

A peristaltic pumping apparatus and associated method to control power to the pump rotor to establish, during a preestablished first time period, a selected first angular velocity and sequentially establishing during a preestablished second time period immediately following the first time period a second angular velocity different than the first angular velocity. In this fashion, the apparatus and method achieve flow rates well below the minimum continuous flow rate of the rotor.

Claims

1. A peristaltic pumping apparatus comprising

a peristaltic pumping element including a pump rotor carrying a rotor for contacting a flexible tubing, and a drive mechanism for rotating the rotor, and

a control mechanism coupled to the drive mechanism and a power source, the control mechanism being sequentially operative

(i) in a continuous mode for controlling power to the drive mechanism to continuously rotate the pump rotor more than one complete revolution at a first angular velocity selected to achieve a first selected flow rate, and

(ii) in an intermittent mode for controlling power to the drive mechanism to rotate the pump rotor in a series of pulses, each pulse having a preestablished first time period, during which the pump rotor rotates less than one complete revolution at a selected second angular velocity less than the first angular velocity and a preestablished second time period immediately following the first time period, during which rotation of the rotor ceases, the series of pulses providing a second selected flow rate less than the first selected flow rate.