Dual-Plunger Drug Dosing Pump With Separated Reservoir Architecture
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Solution Overview
Problem
Conventional drug delivery systems with integrated reservoirs and plungers require large cross-sectional areas, leading to increased dosing increments, friction, and the need for powerful motors due to larger plungers and drag, necessitating a configuration that allows for smaller cross-sectional areas while maintaining effective drug delivery.
Innovation Solution
A dual-plunger system with a separated reservoir and pump chamber connected by conduits with one-way valves, utilizing leadscrews with opposite threads to control plunger movement for efficient liquid transfer, and a non-circular pump chamber shape to prevent plunger rotation, allowing for smaller cross-sectional areas and reduced motor power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reservoir and plunger are integrated in a single unit, then the device structure is simplified, but the cross-sectional area increases leading to larger dosing increments and higher friction
Solution Approach 1:
The device is divided into separate components: the reservoir is separated from the pump chamber, and the plunger is separated from the reservoir. This segmentation allows each component to be optimized independently, enabling a smaller cross-sectional area in the pump chamber while maintaining the drug storage capacity in the separate reservoir.
Solution Approach 2:
The plunger is extracted from the reservoir and placed only in the pump chamber. This extraction allows the reservoir to be optimized for drug storage while the pump chamber is optimized for delivery with minimal cross-sectional area, eliminating the need for the plunger to accommodate the entire reservoir volume.
2Quantity of substance
If a larger cross-sectional area is used, then the reservoir can hold more drug supply, but the plunger diameter increases leading to more drag and friction on sealing surfaces
Solution Approach 1:
The drug supply is segmented between a large-capacity separate reservoir and a small-volume pump chamber. The reservoir stores the full drug supply while the pump chamber holds only the immediate dose, allowing the plunger to operate with minimal cross-sectional area and thus minimizing friction and drag on sealing surfaces.
Solution Approach 2:
A separate reservoir acts as an intermediary between the drug supply and the pump chamber. This intermediary allows the system to maintain large drug storage capacity while the pump chamber maintains minimal cross-sectional area, eliminating the direct relationship between storage capacity and plunger size that would increase friction.
3Force
If a larger plunger is used to achieve given pressure, then the force required is reduced, but the motor size and power requirements increase
Solution Approach 1:
The plunger is extracted from the reservoir and confined to the small pump chamber. This extraction allows the use of a smaller plunger with minimal cross-sectional area, which reduces the force required to move it and enables the use of a smaller, less powerful motor while still achieving the necessary delivery pressure through the focused action in the small chamber.
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 system achieves efficient drug delivery with a smaller cross-sectional area, reducing friction and motor power needs, enhancing patient comfort and extending drug effectiveness by minimizing plunger interaction with liquid constituents.
Implementation Method 1
A linear-actuated drug dosing system includes a pump chamber, a leadscrew, a plunger coupled to the leadscrew
Implementation Method 2
A linear-actuated drug dosing system includes a pump chamber, a leadscrew, a plunger coupled to the leadscrew such that rotation of the leadscrew causes the plunger to move away from a closed end of the pump chamber to draw liquid from the reservoir into the pump chamber and rotation of the leadscrew in a second, opposite direction causes the plunger to move toward the closed end of the pump chamber to force the liquid from the pump chamber to a patient interface
Data Source
AI summary
A novel embodiment of a pump system, for example, of the type that would be used in a wearable drug delivery system, comprises dual linear-actuated plungers disposed in a pump chamber. The plungers are coupled to a leadscrew having both left-hand and right-hand threads such that rotation of leadscrew in a first direction moves the plungers together and rotation of leadscrew in a second, opposite direction moves the plungers apart. Movement of the plungers away from each other draws one or more doses of a liquid drug from a reservoir into the pump chamber, while movement of the plungers together forces liquid drug to a patient interface for delivery to the patient.