Infusion Pump Flow Regulator with Helical Channel and Diaphragm Valve
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Solution Overview
Problem
Disposable ambulatory infusion pumps experience variability in flow rate due to changes in upstream pressure, leading to inaccurate medication delivery and reduced precision compared to electronic pumps.
Innovation Solution
A flow regulator apparatus comprising a cylinder assembly with a spiral or helical thread, longitudinal grooves, and independent liquid-flow passages, along with a diaphragm valve, which maintains consistent flow rates by regulating fluid communication and adjusting to pressure changes, allowing for precise control of fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mechanical restrictor is used to determine flow rate in disposable infusion pumps, then the device achieves simplicity and light weight, but flow rate accuracy deteriorates due to variability from upstream pressure changes
Solution Approach 1:
The flow path is divided into multiple independent liquid-flow passages with different lengths and resistance characteristics. This segmentation allows the system to compensate for pressure variations by providing multiple flow paths that collectively maintain consistent flow rate despite upstream pressure changes.
Solution Approach 2:
The flow regulator incorporates a diaphragm valve that dynamically adjusts the flow path configuration based on pressure conditions. The valve can selectively open or close certain passages depending on upstream pressure, thereby maintaining optimal flow rate accuracy across varying pressure conditions while keeping the overall device simple.
2Device complexity
If the flow rate is determined by the dimensions of the flow restrictor and pressure source, then the device configuration is simple, but flow rate consistency deteriorates due to pressure variations throughout infusion
Solution Approach 1:
The system changes the effective flow path parameters (length, cross-section, resistance) by selectively activating different liquid-flow passages through the diaphragm valve. This allows the flow characteristics to be adjusted in response to pressure changes, maintaining flow rate consistency without complex mechanical adjustments.
Solution Approach 2:
The diaphragm valve acts as a feedback mechanism that responds to upstream pressure changes and automatically adjusts the flow path configuration. This closed-loop control ensures that flow rate consistency is maintained throughout the infusion period despite variations in reservoir pressure.
3Device complexity
If a single flow restrictor is used, then the device structure is simple, but the ability to provide multiple flow rates and bolus doses is lost
Solution Approach 1:
The flow path is segmented into multiple independent passages that can be selectively activated. This allows the device to provide different flow rates by opening different combinations of passages, and to deliver bolus doses by selectively opening high-flow passages, all while maintaining a relatively simple overall structure.
Solution Approach 2:
The multiple liquid-flow passages serve multiple functions: they provide different steady flow rates for continuous infusion, enable bolus dose delivery through selective activation, and offer flow rate adjustment capabilities. This multi-functionality is achieved within a simple structural framework.
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 flow regulator achieves consistent flow rates across the entire infusion period, minimizing the effects of upstream and downstream pressure variations, and providing precise control over medication delivery, rivaling the accuracy of electronic pumps.
Implementation Method 1
a diaphragm valve configured to regulate fluid communication between the spiral liquid-flow channel and the outlet
Implementation Method 2
a continuous spiral or helical thread formed into the first interior surface of the first cylinder; a spiral or helical liquid-flow channel formed between the first cylinder and the second cylinder through the continuous spiral thread
Data Source
AI summary
An ambulatory drug infusion system includes a disposable ambulatory infusion pump and a flow regulator for regulating flow of the drug supplied from the disposable ambulatory infusion pump. The flow regulator includes a cylinder assembly of first, second and third cylinders arranged coaxially. The flow regulator includes a continuous spiral or helical liquid-flow channel formed between the first cylinder and the second cylinder fitted into the first cylinder. The regulator includes bypass through-holes in communication with the spiral or helical channel and formed in the second cylinder. The regulator further includes liquid-flow passages formed between the second cylinder and the third cylinder fitted into the second cylinder. The through-holes are in communication with the passages, respectively. One of the passages can be selected to choose a predetermined flow rate. The regulator further includes a diaphragm valve which can regulate fluid communication between the spiral liquid-flow channel and an outlet.