In-line actuator for electromagnetic operation

• US 8,197,234 B2
• Filed: 05/24/2005
• Issued: 06/12/2012
• Est. Priority Date: 05/25/2004
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Gharib, Morteza, Rinderknecht, Derek, Barbic, Mladen
• Primary Examiner(s): Freay, Charles
• Assistant Examiner(s): BOBISH, CHRISTOPHER S
• Application Number:
  US11/137,853
• Publication Number:
  US 20050275494A1
• Time in Patent Office: 2,576 Days
• Field of Search: 417/474, 417/478, 417/322, 417/412, 92/91, 251/4, 251/65
• US Class Current: 417/474
• CPC Class Codes: A61M 2205/0244 Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F04B 43/12 having peristaltic action
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system
• CPC Class Codes: H02K 41/031 of the permanent magnet type
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06
• CPC Class Codes: H02K 99/20 Motors

Abstract

An electromagnetic actuator for a microfluidic pump of the type that causes periodic pinching and releasing against the walls of a fluidic channel, e.g., a tube. At least one permanent magnet is placed against the walls of the fluidic channel, and located in an area with magnetic fields, produced by coils that are radially symmetric to the channel. The permanent magnet is cause to press and release against the wall of the fluid channel to cause a fluid flow through the channel.

Claims

1. An electromagnetic pump for pumping fluid, comprising:

a wall defining a fluidic channel along a length of the fluidic channel, said wall having an outer surface, and an inner surface, where an area wholly enclosed within the inner surface defines the fluidic channel along an axis;

at least one coil, which is outside said wall and which extends completely around the fluidic channel and which extends along only a portion of said fluidic channel; and

an effected part, located in an area within a magnetic field of said coils to be moved by said magnetic field in an area of said fluidic channel, said effected part extending completely around said fluidic channel, and an entirety of said effected part is moved by said magnetic field of said coils to change a size of the fluidic channel completely around said fluidic channel, but in only said portion which is only part of said length of said fluidic channel where said effected part is located, wherein said effected part is at least one permanent magnet material that is located embedded within said wall in an area of said wall that is completely between said outer surface and said inner surface, and where no part of said permanent magnet extends into the fluidic channel, and where no part of said the fluidic channel, other than said portion, is effected by the actuation of said effected part; and

a controller for controlling a movement of said effected part, by causing periodic pinching of said effected part at a frequency that is based on a desired flow rate for pumping and where the frequency of pumping is controlled to create wave reflections in the fluid.

2. The pump as in claim 1, wherein said coil includes a first coil part and a second coil part, both said first and second coil parts being cylindrically symmetric to the fluidic channel.

3. The pump as in claim 2, further comprising an electrical connection between said first and second coil parts.

4. The pump as in claim 1, further comprising a connection to a source of power that drives said at least one coil.

5. The pump as in claim 4, wherein said source of power drives said at least one coil with an alternating current, and further comprises a device which adjusts at least one parameter of said alternating current.

6. The pump as in claim 5, wherein said at least one parameter is a frequency of said alternating current.

7. The pump as in claim 1, wherein said fluidic channel is a channel with a first fluidic characteristic, further comprising a second channel with a second fluidic characteristic, coupled to said fluidic channel, forming a pumping mechanism.

8. A method of pumping fluid through a channel, comprising:

forming a magnetic field along an axis defined by a fluidic channel with a wall defining the fluidic channel, said forming being carried out from outside said fluidic channel, said wall having an outer surface, and an inner surface, where an area wholly enclosed within the inner surface defines the fluidic channel, said magnetic field defined by lines of force that extend along said the axis, and where the fluidic channel extends along a length;

using said magnetic field to move a magnetic field effected part that effects said fluidic channel, wherein said forming the magnetic field comprises embedding permanent magnetic material into walls of the fluidic channel in an area of said wall that is completely between said outer surface and said inner surface, and where no part of said magnetic material extend into the fluidic channel, and where said magnetic material completely surround said fluidic channel and collectively cause a change in a size of said fluidic channel in only a single location along said length, where that single location is always the same location along said length which is less than entire length, and said fluidic channel is changed in only said single location that is only part of the length of the fluidic channel, wherein said forming a magnetic field comprises using a first and a second coil part that each completely surround said fluidic channel, and that extend along said axis and are separated from one another along said axis, with a first coil part in a first location relative to said axis, surrounding said fluidic channel at said first location, and said second coil part at a second location relative to said axis, surrounding said fluidic channel at said second location, where the effected part is between said first and second coil parts in an area that separates said first and second coil parts;

controlling a movement of said effected part, by causing periodic pinching of said effected part at a frequency and where the frequency of pumping is controlling to create wave reflections in the fluid.

9. A method as in claim 8, wherein said using the magnetic field comprises embedding at least one permanent magnet as said magnetic elements into walls that define the fluidic channel.

10. A method as in claim 8, wherein there is a wire extending between said coil parts.

11. A method as in claim 8, further comprising electrically connecting said first and second coil parts using a wire that extends within said wall of said fluidic channel.

12. A method as in claim 8, further comprising driving the first and second coil parts in phase with one another.

13. A method as in claim 8, further comprising using movement of the magnetic field effected part to pump a fluid.

14. A method as in claim 8, further comprising electrically connecting said first and second coil parts using a wire that extends within said wall of said fluidic channel.

15. A pumping system, comprising:

a first fluidic channel having first properties, said fluidic channel having an outer surface, and an inner surface, where an area wholly enclosed within the inner surface defines the first fluidic channel;

a second fluidic channel, coupled to the first fluidic channel, and having second properties different than the first properties; and

an actuator, on said first fluidic channel, having coil parts which are radially symmetric to the first fluidic channel, and having a magnetic effected part formed within an area of a magnetic field of said coil parts, said magnetic effected part including a permanent magnet material, and operating to compress the first fluidic channel to thereby cause fluid in the first fluidic channel to be pumped relative to the second fluidic channel, wherein said magnetic effected part is embedded within a wall of the first fluidic channel in an area of said wall that is completely between said outer surface and said inner surface, and where no part of said magnetic effected part extends into the fluidic channel, and where said magnetic effected part causes a change of size of the fluidic channel in only a single location along said first fluidic channel where said magnetic effected part is located, and less than a complete length of said first fluidic channel where that single location is always the same location, and where said effected part extending completely around said fluidic channel, and an entirety of said effected part is moved by said magnetic field of said coils to change a size of the fluidic channel completely around said fluidic channel; and

a controller for controlling a movement of said effected part, by causing periodic pinching of said effected part at a frequency and where the frequency of pumping is controlled to create wave reflections in the fluid.

16. A pumping system as in claim 15, wherein said coil parts are embedded within a wall of the first fluidic channel in an area of said wall that is completely between said outer surface and said inner surface.

17. A pumping system as in claim 16, wherein there are two sets of inductive coils, spaced from one another and both embedded in the said wall between said inner surface and said outer surface, and a wire extending between said inductive coils, said wire extending between said inductive coils, said wire extending between said inductive coils wherein said forming a magnetic field comprises using coil parts that are cylindrically symmetrical to the fluidic channel.