Piezoelectric micropump having actuation electrodes and stopper members

• US 5,759,015 A
• Filed: 06/05/1996
• Issued: 06/02/1998
• Est. Priority Date: 12/28/1993
• Status: Expired due to Term

• Current Assignee: Debiotech S.A.
• Original Assignee: Westonbridge International Limited
• Inventors: Neftel, Frederic, Van Lintel, Harald, Poscio, Patrick
• Primary Examiner(s): MCANDREWS JR, ROLAND G
• Application Number:
  US08/640,797
• Time in Patent Office: 727 Days
• Field of Search: 417/413.1, 417/413.2, 417/413.3, 417/322, 92/13.2
• US Class Current: 417/322
• CPC Class Codes: F04B 43/046 with piezoelectric drive

Abstract

A micropump including two glass sheets (2, 8) with a machined silicon board (6) sealingly inserted therebetween. An inlet valve (12), a pumping chamber (50) and an outlet valve (28) are arranged between an inlet (10) and an outlet (4). A pump diaphragm (56) forming one wall of the pumping chamber comprises a thickened central portion (58) interacting with the upper sheet (8) to form an abutment restricting the suction movement of the diaphragm (50), and lower abutment elements (60) restricting the movement of the diaphragm when the fluid is discharged. A piezoelectric pad (72) engages the diaphragm by means of an intermediate part (84) to perform the pumping movement between upper and lower limits precisely defined by the abutments. A precisely defined and constant flow rate is thus achieved regardless of changes in the performance of the piezoelectric pad.

Claims

1. A micropump including at least one base plate (2), at least one upper plate (8) and one intermediate plate (6) sandwiched between the two other plates (2, 8) and shaped so as to define a pumping chamber (50), at least one control member (12) for the inflow of the fluid to connect the pumping chamber with at least one inlet (10) to the micropump and at least one control member (38) for the outflow of the fluid to connect the pumping chamber (50) with at least one outlet (4) of the micropump, the pumping chamber (50) including a movable wall (56, 156, 256) which is machined in the intermediate plate (6) and which can be displaced in two opposite directions during the suction of a fluid from the inlet (10) to the pumping chamber (50) or during the expelling of this fluid from the pumping chamber to the outlet (4), actuating means (70, 170, 270) being provided to move said movable wall (56, 156, 256) to cause a periodical variation of the volume of the pumping chamber (50), characterized in that the micropump includes first and second stopper members arranged in such a manner as to limit the amplitude of the movement of the movable wall (56, 156, 256) in said two opposite directions, with the first stopper members (58, 62, 64;

158, 162, 164;

258,

     270) limiting this movement during the sucking of the fluid inside the pumping chamber (50) and the second stopper members (2, 60;

2, 160;

2,

     260) limiting this movement during the expelling of fluid from the pumping chamber (50).

2. A micropump according to claim 1, characterized in that a face of the movable wall (56) which is directed inwards of the pumping chamber (50) includes at least one protrusion (60, 160, 260) forming, with the base plate (2), the second stopper members limiting the movement during the expelling of the fluid.

3. A micropump according to claim 1, characterized in that the first stopper members are provided as at least one adjustable screw (90, 265) extending through the upper plate (8), each said at least one adjustable screw having one end positioned facing the movable wall (56, 256).

4. A micropump according to claim 3, characterized in that a piezoelectric member (270) is sandwiched between said end of the at least one adjustable screw (265) and the movable wall (256) and is bonded to this wall.

5. A micropump according to claim 3, characterized in that the at least one adjustable screw (90,265) is made of a material capable of compensating the variations in the shape of the movable wall (56, 256) due to the effects of temperature.

7. Use of a micropump according to claim 1 for the administration of medicinal drugs, the micropump being implanted into the body of a patient.

6. A micropump, including at least one base plate (2), at least one upper plate (8) and one intermediate plate (6) sandwiched between the two other plates (2, 8) and shaped so as to define a pumping chamber (50), at least one control member (12) for the inflow of the fluid to connect the pumping chamber with at least one inlet (10) to the micropump and at least one control member (38) for the outflow of the fluid to connect the pumping chamber (50) with at least one outlet (4) of the micropump, the pumping chamber (50) including a movable wall (56, 156, 256) which is machined in the intermediate plate (6) and which can be displaced in two opposite directions during the suction of a fluid from the inlet (10) to the pumping chamber (50) or during the expelling of this fluid from the pumping chamber to the outlet (4), actuating means (70, 170, 270) being provided to move said movable wall (56, 156, 256) to cause a periodical variation of the volume of the pumping chamber (50), wherein the micropump includes first and second stopper members arranged in such a manner as to limit the amplitude of the movement of the movable wall (56, 156, 256) in said two opposite directions, with the first stopper members (58, 62, 64;

158, 162, 164;

258,

     270) limiting this movement during the sucking of the fluid inside the pumping chamber (50) and the second stopper members (2, 60;

2, 160;

2,

     260) limiting this movement during the expelling of fluid from the pumping chamber (50).

wherein said micropump includes expulsion control electrodes (44,

     46) placed one facing each other, one (44) of said expulsion control electrodes being mounted on one movable wall placed downstream of the pumping chamber (50), in such a manner as to control the expelling of the fluid from the micropump.

8. A micropump, including at least one base plate (2), at least one upper plate (8) and one intermediate plate (6) sandwiched between the two other plates (2, 8) and shaped so as to define a pumping chamber (50), at least one control member (12) for the inflow of the fluid to connect the pumping chamber with at least one inlet (10) to the micropump and at least one control member (38) for the outflow of the fluid to connect the pumping chamber (50) with at least one outlet (4) of the micropump, the pumping chamber (50) including a movable wall (56, 156, 256) which is machined in the intermediate plate (6) and which can be displaced in two opposite directions during the suction of a fluid from the inlet (10) to the pumping chamber (50) or during the expelling of this fluid from the pumping chamber to the outlet (4), actuating means (70, 170, 270) being provided to move said movable wall (56, 156, 256) to cause a periodical variation of the volume of the pumping chamber (50), wherein the micropump includes first and second stopper members arranged in such a manner as to limit the amplitude of the movement of the movable wall (56, 156, 256) in said two opposite directions, with the first stopper members (58, 62, 64;

158, 162, 164;

258,

     270) limiting this movement during the sucking of the fluid inside the pumping chamber (50) and the second stopper members (2, 60;

2, 160;

2,

     260) limiting this movement during the expelling of fluid from the pumping chamber (50);

wherein the movable wall (56) includes a central rigid part (58) surrounded by a resilient edge (61) of a smaller thickness integral with the central rigid part (58), the central rigid part (58) protruding relatively with respect to a face of the movable wall (56) which is opposite to the pumping chamber (50) and being designed for coming in contact with the plate (2,

     8) which is positioned facing the same for providing said first stopper members limiting the movement of the movable wall (56) during the sucking of the fluid.

9. A micropump according to claim 8, characterized in that a width of said central rigid part (58) represents between 20% and 90% of an overall width of the movable wall (56), and preferably between 50% and 80%.

10. A micropump including at least one base plate (2), at least one upper plate (8) and one intermediate plate (6) sandwiched between the two other plates (2, 8) and shaped so as to define a pumping chamber (50), at least one control member (12) for the inflow of the fluid to connect the pumping chamber with at least one inlet (10) to the micropump and at least one control member (38) for the outflow of the fluid to connect the pumping chamber (50) with at least one outlet (4) of the micropump, the pumping chamber (50) including a movable wall (56, 156, 256) which is machined in the intermediate plate (6) and which can be displaced in two opposite directions during the suction of a fluid from the inlet (10) to the pumping chamber (50) or during the expelling of this fluid from the pumping chamber to the outlet (4), actuating means (70, 170, 270) being provided to move said movable wall (56, 156, 256) to cause a periodical variation of the volume of the pumping chamber (50), wherein the micropump includes first and second stopper members arranged in such a manner as to limit the amplitude of the movement of the movable wall (56, 156, 256) in said two opposite directions, with the first stopper members (58, 62, 64;

158, 162, 164;

258,

     270) limiting this movement during the sucking of the fluid inside the pumping chamber (50) and the second stopper members (2, 60;

2, 160;

2,

     260) limiting this movement during the expelling of fluid from the pumping chamber (50);

wherein the actuator means (70) include a driving member (72) mounted movably on either the base plate or the upper plate (2,

     8) and an intermediate part (84) placed between the movable wall (56) and the driving member (72).

11. A micropump according to claim 10, characterized in that the driving member (72) is mounted movably on a outer face of said upper plate (8), said intermediate part (84) extending through the upper plate (8) via an opening (89).

12. A micropump according to claim 11, characterized in that the driving member is a piezoelectric member (72, 80) which is mounted via a spacer member (82) on the outer face of the upper plate (8).

13. A micropump according to claim 11, characterized in that the intermediate part (84) includes a flat head (86) integral with the piezoelectric member (72, 80) and a rod (88) extending through the upper plate (8) and acting by its end on the movable wall (56).

14. A micropump, including at least one base plate (2), at least one upper plate (8) and one intermediate plate (6) sandwiched between the two other plates (2, 8) and shaped so as to define a pumping chamber (50), at least one control member (12) for the inflow of the fluid to connect the pumping chamber with at least one inlet (10) to the micropump and at least one control member (38) for the outflow of the fluid to connect the pumping chamber (50) with at least one outlet (4) of the micropump the pumping chamber (50) including a movable wall (56, 156, 256) which is machined in the intermediate plate (6) and which can be displaced in two opposite directions during the suction of a fluid from the inlet (10) to the pumping chamber (50) or during the excelling of this fluid from the pumping chamber to the outlet (4), actuating means (70, 170, 270) being provided to move said movable wall (56, 156, 256) to cause a periodical variation of the volume of the pumping chamber (50), wherein the micropump includes first and second stopper members arranged in such a manner as to limit the amplitude of the movement of the movable wall (56, 156, 256) in said two opposite directions, with the first stopper members (58, 62, 64;

158, 162, 164;

258,

     270) limiting this movement during the sucking of the fluid inside the pumping chamber (50) and the second stopper members (2, 60;

2, 160;

2,

     260) limiting this movement during the expelling of fluid from the pumping chamber (50);

wherein said micropump includes electrodes (62, 64;

162, 164;

262,

     264) placed facing each other on the movable wall (56;

156;

     256) and on the upper plate (8), these electrodes being connected to a circuit which makes it possible to control the functioning of the deformable wall (56;

156;

     256).

15. A micropump, including at least one base plate (2), at least one upper plate (8) and one intermediate plate (6) sandwiched between the two other plates (2, 8) and shaped so as to define a pumping chamber (50), at least one control member (12) for the inflow of the fluid to connect the pumping chamber with at least one inlet (10) to the micropump and at least one control member (38) for the outflow of the fluid to connect the pumping chamber (50) with at least one outlet (4) of the micropump, the pumping chamber (50) including a movable wall (56, 156, 256) which is machined in the intermediate plate (6) and which can be displaced in two opposite directions during the suction of a fluid from the inlet (10) to the pumping chamber (50) or during the expelling of this fluid from the pumping chamber to the outlet (4), actuating means (70, 170, 270) being provided to move said movable wall (56, 156, 256) to cause a periodical variation of the volume of the pumping chamber (50), wherein the micropump includes first and second stopper members arranged in such a manner as to limit the amplitude of the movement of the movable wall (56, 156, 256) in said two opposite directions, with the first stopper members (58, 62, 64;

158, 162, 164;

258,

     270) limiting this movement during the sucking of the fluid inside the pumping chamber (50) and the second stopper members (2, 60;

2, 160;

2,

     260) limiting this movement during the expelling of fluid from the pumping chamber (50);

wherein the movable wall (156) consists of a membrane exhibiting a central part (158) protruding in such a manner as to provide with the upper plate (8) said first stopper members, this central part being surrounded by a piezoelectric member (172) bonded to the membrane and exhibiting a first central bore (173) for the passage of the central part (158).