In-plane electromagnetic MEMS pump
Inventors
Carlson, Gregory A. • Foster, John S. • Gudeman, Christopher S. • Hovey, Steven S. • Rubel, Paul J.
Assignees
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Publication Number
US-8690830-B2
Publication Date
2014-04-08
Expiration Date
Abstract
A micromechanical pumping system is formed on a substrate surface. The pumping system uses a pumping element which pumps a fluid through valves which move in a plane substantially parallel to the substrate surface. An electromagnetic actuating mechanism may also be fabricated on the surface of the substrate. Magnetic flux produced by a coil around a permeable core may be coupled to a permeable member affixed to a pumping element. The permeable member and pumping element may be configured to move in a plane parallel to the substrate. The electromagnetic actuating mechanism gives the pumping system a large throw and substantial force, such that the fluid pumped by the pumping system may be pumped through a transdermal cannula to deliver a therapeutic substance to the tissue underlying the skin of a patient.
Core Innovation
The disclosure relates to an in-plane electromagnetic MEMS pump formed on a substrate surface, in which a pumping element having a magnetically permeable portion moves in a plane substantially parallel to the top surface and exerts a pumping force on fluid. The fluid moves in a direction substantially in the plane, together with at least one fluid valve that is formed on the top surface of the substrate and configured to move in a plane substantially parallel to the top surface.
The pump architecture includes magnetically permeable members and an electromagnetic actuator, where flux and magnetic force generation are provided with a coil arrangement coupled across a narrow gap to magnetically permeable structures. The disclosure further provides multiple embodiment variations for the pumping element and valving, including piston or diaphragm pumping elements and passive versus active valves, with valve movement facilitated by hinges or other permeable-member geometries.
In addition to the in-plane microfabricated fluid pump, the disclosure describes a drug-delivery system that uses the microfabricated fluid pump to deliver a therapeutic substance from a reservoir through a cannula to a region beneath an outer layer of skin. The pump and related components are described as being microfabricated with small characteristic dimensions and configured for control by microprocessor and sensor-based elements.
Claims Coverage
The provided excerpt includes one independent claim covering the microfabricated in-plane fluid pump concept using a magnetically permeable pumping element and planar fluid valves with in-plane movement, plus dependent claims that refine the electromagnetic force generation, valve behavior, system-level therapeutic delivery context, and manufacturing approach.
Microfabricated fluid pump with in-plane pumping element and planar valve
A microfabricated fluid pump with a substrate having a top surface, at least one fluid valve formed on the top surface configured to move in a plane substantially parallel to the top surface, and a pumping element with a magnetically permeable portion where the pumping element moves in the plane substantially parallel to the top surface and exerts a pumping force on fluid, with the pumping element and the at least one fluid valve moving the fluid in a direction substantially in the plane.
Substrate-separable electromagnetic force generation with flux transfer across a narrow gap
The microfabricated fluid pump uses an electromagnetic, substrate-separable magnetic force-generating mechanism that transfers flux to the substrate across a narrow gap.
Planar pancake coil wrapped around a magnetically permeable core
The microfabricated fluid pump specifies that its force-generating mechanism is a planar, pancake coil wrapped around a magnetically permeable core.
Passive in-plane valve movement using a hinge actuated by fluid pressure
The microfabricated fluid pump includes a passive valve actuated by fluid pressure, with a hinge that allows valve movement in a plane substantially parallel to the substrate top surface.
Electroplating into a cavity followed by planarization and deep reactive ion etching
A fabrication approach includes electroplating magnetically permeable material into a silicon-on-insulator device-layer cavity, chemical-mechanical planarizing the deposited material, and deep reactive ion etching the pumping-element outline in the device layer.
Therapeutic-delivery system with reservoir and cannula for delivery beneath skin
A system delivers a therapeutic substance from a reservoir through a microfabricated fluid pump and cannula to a region beneath the patient’s outer layer of skin, with the pump having a characteristic dimension of less than 1000 μm.
Overall, the claim set coverage in the provided excerpt centers on a microfabricated fluid pump that pumps fluid in an in-plane direction by moving a magnetically permeable pumping element and planar fluid valves in a plane parallel to the substrate surface, with refinements to the magnetic actuator architecture, valve/hinge behavior, therapeutic delivery system context, and magnetically permeable and pumping structure fabrication.
Stated Advantages
Enables in-plane fluid pumping using an electromagnetic MEMS pump architecture with magnetically permeable pumping and planar valves.
Supports therapeutic delivery from a reservoir through a microfabricated fluid pump and cannula to a region beneath the patient’s outer layer of skin.
Documented Applications
Delivery of a therapeutic substance from a reservoir through a microfabricated fluid pump and cannula to a region beneath a patient’s outer layer of skin.
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