Infusion Pump Drive Spring Compression Mechanism
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Solution Overview
Problem
Infusion pumps face challenges in delivering fluids with consistent flow rates and overcoming stiction friction at low displacement rates, particularly when dealing with high viscosity fluids and large volumes, which can result in force spikes and inefficiencies.
Innovation Solution
A hybrid drive system incorporating a spring in line with a transmission component, which compresses and expands to apply a constant or varying force to a stopper within a reservoir, allowing for continuous or intermittent fluid dispensing, and featuring a compact design using torsional springs for reduced size and increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a direct drive motor is used to deliver fluid at low flow rates, then the pump can operate continuously, but the motor operates at low efficiency and experiences force spikes due to stiction friction
Solution Approach 1:
The patent employs periodic action by using an intermittent drive mechanism where the motor operates in short bursts to advance a belt or cable, which then uses elastic storage (spring or elastic band) to maintain fluid delivery during idle periods. This allows the motor to operate at higher efficiency intervals rather than continuously at low efficiency, resolving the contradiction between productivity and energy loss.
2Measurement precision
If the pump operates at low displacement rates to achieve precise dosing, then dosing accuracy is improved, but stiction friction causes force spikes and inefficiencies
Solution Approach 1:
The patent applies beforehand cushioning by incorporating an elastic element (spring or elastic band) that pre-absorbs and smooths out force variations. This elastic storage acts as a buffer between the motor and the fluid delivery mechanism, cushioning against force spikes generated by stiction friction during low-speed operation, thereby maintaining dosing accuracy while reducing harmful mechanical shocks.
3Volume of moving object
If a spring mechanism is used to drive the stopper, then the pump size can be reduced, but the spring must be compact which limits design options
Solution Approach 1:
The patent employs flexible shells and thin films by using an elastic band or flexible membrane as the storage element instead of a traditional coil spring. This flexible element can be integrated into the pump housing or reservoir wall, providing the necessary elastic storage in a compact, space-efficient manner that reduces overall pump volume while avoiding the design constraints of rigid spring mechanisms.
4Loss of energy
If the motor operates at high speed for short durations, then energy efficiency is improved, but the mechanical transmission components experience higher wear
Solution Approach 1:
The patent uses an intermediary element (elastic band or spring) between the motor and the fluid delivery mechanism. This intermediary absorbs and smooths out the high-speed, short-duration motor pulses, converting them into continuous, low-speed motion for the stopper. This mediation protects the transmission components from high-speed wear while allowing the motor to operate efficiently at higher speeds intermittently.
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 hybrid drive system achieves up to 10 times greater efficiency compared to direct drive motors by operating at faster speeds for shorter durations, providing consistent fluid delivery and mitigating force spikes, while also allowing for compact design suitable for both mobile and hospital settings.
Implementation Method 1
Displacement of the transmission component compresses the spring to apply a force to a stopper that is moveable within a reservoir
Implementation Method 2
expanding the spring displaces the stopper in a reservoir to dispense a volume of fluid from the reservoir
Data Source
AI summary
An infusion pump drive and its methods of use are disclosed. In one embodiment, the infusion pump drive may include a transmission component and a spring in line with the transmission component. Displacing the transmission component may compress the spring to apply a force causing fluid to dispense from an associated reservoir. Depending on the particular embodiment, the transmission component may either be displaced continuously or displaced multiple times to dispense fluid from the reservoir.