Micropump

• US 9,222,470 B2
• Filed: 03/15/2011
• Issued: 12/29/2015
• Est. Priority Date: 03/17/2010
• Status: Active Grant

• Current Assignee: Sensile Medical AG (Gerresheimer AG)
• Original Assignee: Sensile Pat Ag
• Inventors: Genoud, Dominique, Christen, Peter, Robin, Franck, Thiemer, Helmut
• Primary Examiner(s): Comley, Alexander
• Application Number:
  US13/635,010
• Publication Number:
  US 20130017099A1
• Time in Patent Office: 1,750 Days
• Field of Search: 417/9, 417/50, 417/491, 417/492, 417/498, 417/500, 415/172.1, 137/614.2
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: A61M 5/36 with means for eliminating or preventing injection or infusion of air into body dialysis systems, blood oxygenators A61M1/14; haemofiltration equipment A61M1/34; automatic tube cut-off A61M39/281
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 7/045 Two pistons coacting within one cylinder
• CPC Class Codes: F04B 7/06 the pistons and cylinders being relatively reciprocated and rotated
• CPC Class Codes: F04B 9/042 the means being cams
• CPC Class Codes: F04B 9/047 the means being pin-and-slot mechanisms

Abstract

A pump comprising a housing comprising a rotor chamber, inlet and outlet channels opening into the rotor chamber, and inlet and outlet seals mounted on a surface of the chamber, and a rotor rotatably and axially slidably received in the chamber and comprising a first axial extension comprising a liquid supply channel and a second axial extension comprising a liquid supply channel, the first and second axial extensions having different diameters. The inlet and outlet seals engage a surface of the rotor, whereby the liquid supply channel of each axial extension in conjunction with a corresponding seal forms a valve that opens and closes as a function of the angular and axial displacement of the rotor. At least one of the inlet and outlet channels opens transversely into the rotor chamber and at least one of the inlet and outlet seals forms a closed circuit circumscribing said at least one of the inlet and outlet channels.

Claims

1. A pump comprising:

a housing comprising a rotor chamber, inlet and outlet channels opening into the rotor chamber, and inlet and outlet seals mounted on a surface of the chamber, and a rotor rotatably and axially slidably received in the chamber and comprising a first axial extension comprising a liquid supply channel and a second axial extension comprising a liquid supply channel, the first and second axial extensions having different diameters, said inlet and outlet seals engaging a surface of the rotor, said liquid supply channel of each axial extension in conjunction with a corresponding said seal forming a valve that opens and closes as a function of the angular and axial displacement of the rotor, wherein at least one of the inlet and outlet channels opens radially into the rotor chamber, and wherein at least one of the inlet and outlet seals forms a closed circuit circumscribing said at least one of the inlet and outlet channels opening radially into the rotor chamber, and wherein a surface circumscribed by either the inlet or the outlet seal wraps around the corresponding rotor extension over an angle (α

, β

) less than 360°

.

2. The pump according to claim 1, wherein both inlet and outlet channels open radially into the rotor chamber and both inlet and outlet seals form a closed circuit circumscribing respective inlet and outlet channels.

3. The pump according to claim 1, wherein a surface circumscribed by either the inlet or the outlet seal wraps around the corresponding rotor extension over an angle (α

, β

) less than 180°

.

4. The pump according to claim 1, wherein the rotor is configured to oscillate over a rotation angle less than 360°

, a back and forth movement constituting a pumping cycle.

5. The pump according to claim 1, wherein the rotor is configured to rotate in a single direction, a rotation angle of 360°

constituting a pumping cycle.

6. The pump according to claim 1, wherein the rotor and housing comprise inter-engaging cam elements to effect the rotor axial displacement as a function of the rotation angle, said cam elements comprising a double sided cam slot.

7. The pump according to claim 6, wherein the double sided cam slot comprises a varying width configured to enable leakage or occlusion detection.

8. The pump according to claim 6, wherein the axial displacement during pump filling is defined by a cam section CP3 on one side of the cam slot, and the axial displacement during pump expelling is defined by a cam section CP5′

on an opposite side of the cam slot, the cam surfaces CP3, CP5′

acting as reference surfaces that define the volume of pumped liquid at each cycle.

9. The pump according to claim 6, wherein the cam slot comprises a first portion (39a) defining the axial displacement in one rotation direction, and a second portion (39b) defining the axial displacement in an opposite rotation direction.

10. The pump according to claim 9, wherein at a transition position in the cam slot corresponding to a change in direction of rotation, the cam slot comprises a step down configured to ensure that a cam finger progresses from one cam slot portion to the other cam slot portion.

11. A method of detecting occlusion or leakage of a pump, including:

providing a pump according to claim 1;

performing an initial measurement comprising turning the rotor in a forward pumping direction at least one revolution and storing the axial displacement as a function of rotation displacement profile in a look-up table as a cam profile; and

measuring the rotor axial displacement as a function of rotation displacement during subsequent pumping and comparing the measured rotor displacement with the stored cam profile.

12. The method according to claim 11, wherein before the cam profile setting, the rotor is rotated in a reverse direction until a cam shoulder (CP4) abuts a complementary cam finger, thus setting a defined reference starting position.

13. The method according to claim 11, wherein a back and forth displacement of the rotor is effected over an angle less than 90°

when both valves V1 and V2 are closed to detect leakage.