Eccentric Cam Micropump for Flexible Reservoir Drug Delivery
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Solution Overview
Problem
Existing micropumps for subcutaneous drug delivery are complex and not cost-effective, limiting their adoption as fully disposable, compact, and economical designs, and often require precise actuation and rigid reservoirs, which restricts the use of flexible reservoirs and limits design layouts.
Innovation Solution
A micropump design featuring a piston with an eccentric cam surface within a pump housing, driven by a motor, allowing axial translation and rotational movement to control fluid flow through integrated valves, using a flexible reservoir and a compact, wearable format for continuous medication delivery over 1 to 5 days, with a microcontroller for precise dosage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rigid reservoir with lead screw is used for medication delivery, then precise actuation and calibrated dosing are achieved, but the device complexity increases and flexible reservoirs cannot be used
Solution Approach 1:
The patent replaces the traditional lead screw mechanical system with a rotary piston pump system. The piston rotates within a pump chamber, using centrifugal force and pressure differentials to draw medication from the reservoir and deliver it through the cannula. This substitution eliminates the need for precise linear actuation while maintaining dosing accuracy through rotational control.
Solution Approach 2:
The invention changes the operational parameter from linear displacement (lead screw) to rotational motion (piston). By controlling the rotational speed and position of the piston, the system achieves precise medication delivery without requiring the complex linear actuation mechanisms of traditional designs. The rotary motion creates pressure variations that control fluid flow.
2Reliability
If traditional micropump designs with rotor and stator are used, then medication delivery is achieved, but the device complexity increases and cost-effectiveness decreases
Solution Approach 1:
The patent extracts and eliminates the stator component from the traditional rotor-stator micropump design. The rotary piston performs both the pumping and sealing functions that were previously distributed between rotor and stator. This simplification reduces part count, manufacturing complexity, and cost while maintaining reliable medication delivery through the simplified rotary mechanism.
3Measurement precision
If precise rotational positioning is required for pump operation, then accurate dosing is achieved, but the device complexity and control requirements increase
Solution Approach 1:
The patent employs periodic rotational action of the piston, where each complete rotation delivers a predetermined volume of medication. The dosing accuracy is achieved through the consistent periodic motion rather than precise positioning at specific angular locations. The system uses rotational speed control and timing to regulate dosage, simplifying the control mechanism compared to systems requiring precise angular positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a compact, cost-effective, and precise delivery of medication, enabling continuous infusion over extended periods without the need for precise rotational positioning, using a flexible reservoir and integrated flow control valves, ensuring accurate and efficient dosing.
Implementation Method 1
a piston positioned in the pump housing having a longitudinal piston axis... a motor adapted to rotate the piston about the piston axis
Implementation Method 2
The piston has an eccentric cam surface at one end thereof, said cam surface adapted to open and close the first aperture and the second aperture at respective rotational positions of the piston
Data Source
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AI summary
A micropump according to the invention uses an eccentric cam member (33) rotating within a pump housing to sequentially open and close valves in the pump housing to withdraw fluid from a reservoir and provide metered amounts of the fluid to a cannula port for administration to a patient. The micropump may be used in a disposable pump for continuous infusion of medication such as insulin.