Split-Piston Micropump With Axial Sealing for Precise Drug Dosing
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Solution Overview
Problem
Existing micropumps for subcutaneous drug delivery are complex and costly, and they often require a rigid reservoir, limiting dosing precision and compact design options, especially when trying to deliver medications like insulin.
Innovation Solution
A micropump design featuring a flexible reservoir, a motor, gear, drive rack, and tubular pump housing with axially oriented drive and floating pistons, where the relative position of the pistons defines a pump volume space, allowing for precise fluid delivery through frictional engagement of radial seals, enabling compact and cost-effective operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid reservoir with lead screw is used for medication delivery, then dosing precision can be maintained, but the device layout is limited and flexibility is reduced
Solution Approach 1:
The patent replaces the traditional lead screw mechanical system with a peristaltic pumping mechanism. The roller assembly compresses the flexible reservoir to dispense medication, eliminating the need for rigid reservoirs and lead screws. This substitution maintains dosing precision through controlled compression while enabling flexible reservoir designs and improved device layout options.
Solution Approach 2:
The patent explicitly adopts flexible reservoirs instead of rigid containers. The flexible reservoir works in conjunction with the peristaltic pumping mechanism, where the reservoir wall's flexibility allows for compact integration and varied layouts while the roller assembly provides precise medication delivery through sequential compression.
2Manufacturing precision
If complex micropump designs with rotor and stator are used, then medication delivery precision is achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the complex rotor-stator micropump mechanism from the device. Instead, it employs a simplified peristaltic pumping system consisting of a motor, drive gear, drive rack, and roller assembly that works with the flexible reservoir. This extraction maintains medication delivery precision while dramatically reducing structural complexity and manufacturing cost.
Solution Approach 2:
The patent adopts a disposable pump design where the entire pumping mechanism (motor, gear, rack, roller assembly) is integrated into a single-use unit. This approach simplifies the overall device architecture, eliminates the need for complex reusable components, and reduces manufacturing costs while maintaining dosing precision through the straightforward peristaltic mechanism.
3Manufacturing precision
If motor is directly connected to lead screw for medication actuation, then dosing precision depends on motor precision, but the system requires rigid reservoir and has limited layout options
Solution Approach 1:
The patent introduces a peristaltic pumping mechanism as an intermediary between the motor and the flexible reservoir. The motor drives the gear and rack system, which actuates the roller assembly to compress the reservoir. This intermediary mechanism decouples the motor from direct connection to the reservoir, enabling flexible reservoir designs and varied device layouts while maintaining dosing precision through controlled compression.
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 micropump achieves precise and efficient delivery of medication with a compact design, allowing for flexible reservoir use and varied layouts, enhancing dosing precision and user convenience while minimizing complexity and cost.
Implementation Method 1
The frictional engagement of radial seals on the drive piston and/or the floating piston with the interior surface of the tubular pump housing determines the opening and closing of the apertures in the pump housing
Data Source
AI summary
A micropump according to the invention uses axially oriented pistons to define a pump volume. Translating the pistons axially with respect to each other within a pump housing draws a metered amount of fluid into the pump volume from a reservoir port for delivery to a cannula port when the space is collapsed. Radially situated seals on the pistons cooperate with the axial movement to close off and open the cannula port and the reservoir port respectively at different positions of the piston stroke.