Cam-Driven Reciprocating Pump for Precise Wearable Insulin Dosing
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Solution Overview
Problem
Conventional insulin pumps are bulky, costly, and inconvenient due to their multiple components and tubing, making them less desirable for daily use by diabetes patients.
Innovation Solution
A compact, cost-effective pump design utilizing an axially translatable chamber with a rotatable piston or diaphragm, coupled with a cam and follower mechanism, that translates rotational motion into axial reciprocation, and synchronized valves for precise liquid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional insulin pumps are used, then insulin delivery function is achieved, but device size and complexity increase making them cumbersome and inconvenient
Solution Approach 1:
The pump is divided into distinct functional modules: a rotatable piston for fluid displacement, a cam mechanism for converting rotational to linear motion, check valves for one-way flow control, and a biasing means for maintaining valve contact. This segmentation allows each component to be optimized independently and facilitates compact integration.
Solution Approach 2:
The piston is rotatably received within the chamber, and the cam mechanism is integrated with the piston assembly. The biasing means is positioned to act on the chamber while maintaining contact with the cam mechanism. This nested arrangement minimizes the overall pump volume by eliminating separate mounting structures and reducing inter-component spacing.
2Reliability
If conventional insulin pumps are used, then insulin delivery is achieved, but cost increases due to multiple components
Solution Approach 1:
The cam mechanism and piston are integrated into a single assembly where the cam is affixed to the piston. The biasing means simultaneously maintains contact between the follower and cam surface and ensures proper valve operation. This merging reduces the total component count and simplifies manufacturing while maintaining reliable insulin delivery through the coordinated mechanical action of the integrated components.
3Measurement precision
If precise insulin dosing is achieved, then blood glucose control improves, but pump complexity increases
Solution Approach 1:
The check valves automatically open and close based on pressure differentials created by piston rotation, eliminating the need for externally controlled valve actuation. The biasing means automatically maintains optimal contact force between the follower and cam surface throughout the rotation cycle. This self-regulating behavior ensures precise dosing through purely mechanical means without requiring complex electronic controls or sensors.
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
Enables precise and small liquid dosages, reducing the size of the drug reservoir and prolonging replacement intervals, while maintaining continuous insulin delivery without tubing, thus enhancing user convenience and reducing discomfort.
Implementation Method 1
a cam affixed to the chamber, a follower affixed to the piston and in contact with the cam for axially translating the chamber
Implementation Method 2
a biasing means acting on the chamber for applying a force on the chamber in an axial direction of the chamber to maintain such contact
Implementation Method 3
a piston or a diaphragm rotatably received in the chamber
Data Source
AI summary
A pump suitable for use in a wearable medical device, such as a patch pump, comprises an axially translatable chamber with an inlet and an outlet, a piston or a diaphragm rotatably received in the chamber, a first valve between the inlet and the chamber, a second valve between the outlet and the chamber, a cam affixed to the chamber, a follower affixed to the piston and in contact with the cam for axially translating the chamber, and a biasing means acting on the chamber for applying a force on the chamber in an axial direction of the chamber to maintain such contact.