Peristaltic pump for pumping a liquid and method for operating a peristaltic pump

• US 9,458,846 B2
• Filed: 10/16/2012
• Issued: 10/04/2016
• Est. Priority Date: 10/21/2011
• Status: Active Grant

• Current Assignee: Fresenius Vial SAS (Else Kröner-Fresenius-Stiftung)
• Original Assignee: Fresenius Vial SAS (Else Kröner-Fresenius-Stiftung)
• Inventors: Labarthe, Sebastien, Berthier, Jean-Baptiste
• Primary Examiner(s): Hamo, Patrick
• Application Number:
  US14/351,593
• Publication Number:
  US 20140294610A1
• Time in Patent Office: 1,449 Days
• US Class Current: 1/1
• CPC Class Codes: A61M 5/14228 with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/16859 Evaluation of pressure response, e.g. to an applied pulse
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: F04B 2205/03 Pressure in the compression chamber
• CPC Class Codes: F04B 43/082 the tubular flexible member being pressed against a wall by a number of elements, each having an alternating movement in a direction perpendicular to the axes of the tubular member and each having its own driving mechanism
• CPC Class Codes: F04B 43/12 having peristaltic action
• CPC Class Codes: F04B 49/00 Control , e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
• CPC Class Codes: F04B 49/08 Regulating by delivery pressure
• CPC Class Codes: F04B 49/10 Other safety measures

Abstract

A peristaltic pump (1) for pumping a liquid comprises a flexible tube (2) for guiding the liquid to be pumped, a compression means (5) being actuatable for compressing the flexible tube (2), an upstream valve means (3) arranged in an upstream direction with respect to the compression means (5) and being actuatable to selectively open or close the flexible tube (2) upstream of the compression means (5), and a downstream valve means (4) arranged in a downstream direction with respect to the compression means (5) and being actuatable to selectively open or close the flexible tube (2) downstream of the compression means (5). A drive shaft (6) is provided which is rotatable for periodically actuating the compression means (5), the upstream valve means (3) and the downstream valve means (4). In addition, the peristaltic pump comprises a position detection means (8) for detecting the rotational position of the drive shaft (6) during actuation of the compression means (5), the upstream valve means (3) and the downstream valve means (4), a pressure sensor (7) being arranged between the upstream valve means (3) and the downstream valve means (4) for measuring a pressure signal (P) in the flexible tube (2) at a location between the upstream valve means (3) and the downstream valve means (4), and a control means (9) to control the operation of the peristaltic pump (1), the control means (9) being operative to detect a fault condition during the operation of the peristaltic pump (1) from a measured pressure signal (P). In a peristaltic pump (1) of this kind the control means (9), for detecting the fault condition, is operative to detect a peak (P1, P1′) of the pressure signal (P) in a predefined interval (II) during rotation of the drive shaft (6) and to determine whether the fault condition is present or not by taking the signal value at the peak (P1, P1′) and the location (T1, T1′) of the peak (P1, P1′) in the predefined interval (II) into account. In this way a peristaltic pump is provided allowing for an easy and reliable detection of a fault condition, in particular for detecting an empty-bag condition indicating that a bag supplying liquid to the flexible tube of the peristaltic pump is empty.

Claims

1. A peristaltic pump for pumping a liquid, comprising:

a flexible tube for guiding the liquid to be pumped,

a finger head being actuatable for compressing the flexible tube,

an upstream valve arranged in an upstream direction with respect to the finger head and being actuatable to selectively open or close the flexible tube upstream of the finger head,

a downstream valve arranged in a downstream direction with respect to the finger head and being actuatable to selectively open or close the flexible tube downstream of the finger head,

a drive shaft being rotatable for periodically actuating the finger head, the upstream valve and the downstream valve,

a position detector for detecting the rotational position of the drive shaft during actuation of the finger head, the upstream valve and the downstream valve,

a pressure sensor being arranged between the upstream valve and the downstream valve for measuring a pressure signal (P) in the flexible tube at a location between the upstream valve and the downstream valve, and

a controller to control the operation of the peristaltic pump, the controller being operative to detect a fault condition during the operation of the peristaltic pump from a measured pressure signal (P),

wherein the controller for detecting the fault condition is operative to detect a peak (P1, P1′

) of the pressure signal (P) in a predefined interval (II) during rotation of the drive shaft and to determine whether the fault condition is present or not by taking a value of the signal at a peak (P1, P1′

) and a location (T1, T1′

) of the peak (P1, P1′

) in the predefined interval (II) into account, the signal value at the peak (P1, P1′

) is multiplied by a factor and related to a reference value, wherein the factor is computed using the location (T1, T1′

) of the peak (P1, P1′

) in the predefined interval (II).

2. The peristaltic pump according to claim 1, wherein the controller is operative to detect, as fault condition, whether liquid is supplied to the tube upstream of the upstream valve.

3. The peristaltic pump according to claim 1, wherein during a first portion of the predefined interval (II), both the upstream valve and the downstream valve are closed and the finger head is actuated to compress the flexible tube.

4. The peristaltic pump according to claim 3, wherein during a second portion of the predefined interval (II) the downstream valve is opened to open the flexible tube.

5. The peristaltic pump according to claim 1 wherein the drive shaft carries a disc acting together with the position detection means and indicating intervals (I-VI) during rotation of the drive shaft for periodically actuating the finger head, the upstream valve and the downstream valve.

6. The peristaltic pump according to claim 1, wherein the reference value is determined from a mean value of the pressure signal (P) during an interval (V) of the rotation of the drive shaft during which the upstream valve is opened and the downstream valve is closed.

7. The peristaltic pump according to claim 1 wherein to determine whether the fault condition is present or not, the difference between the signal value at the peak (P1, P1′

) and the reference value is formed to determine a peak height, wherein the peak height is compared to a threshold value to determine whether the fault condition is present or not.

8. The peristaltic pump according to claim 1, wherein

an upstream pressure value is determined from a mean value of the pressure signal (P) during an interval (V) of the rotation of the drive shaft during which the upstream valve is opened and the downstream valve is closed and

a downstream pressure value is determined from a mean value of the pressure signal (P) during an interval (III) of the rotation of the drive shaft during which the upstream valve is closed and the downstream valve is opened,

wherein for detecting an occlusion of the flexible tube upstream of the upstream valve and/or downstream of the downstream valve the upstream pressure value and the downstream pressure value are compared to each other.

9. A method for operating the peristaltic pump of claim 1 for pumping a liquid comprising:

detecting the fault condition by detecting with the controller a peak (P1, P1′

) of the pressure signal (P) in a predefined interval (II) during rotation of the drive shaft and determines whether the fault condition is present or not by taking the signal value at the peak (P1, P1′

) and the location (T1, T1′

) of the peak (P1, P1′

) in the predefined interval (II) into account.