Infusion Pump Actuator Asymmetric Biasing for Orientation-Independent Delivery
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Solution Overview
Problem
Medication infusion pumps face issues with inconsistent delivery rates due to pump orientation and gravity effects, leading to wear and friction variations in their components.
Innovation Solution
The infusion system incorporates an actuator with a piston and armature configuration that includes a biasing member, such as a coil spring, disposed non-concentrically with the piston and piston bore, which stabilizes clearances and reduces wear by applying a side load, ensuring consistent fluidic resistance and stroke volume across orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reciprocating piston actuator is used to deliver infusion media, then the pump can provide periodic delivery of medication, but pump orientation and gravity effects alter clearances between the piston and piston chamber, affecting delivery rate consistency
Solution Approach 1:
The patent applies asymmetry by positioning the biasing member (spring) non-concentrically within the piston chamber, offset from the central axis of the piston. This asymmetric placement creates a side load on the piston that actively compensates for gravity-induced clearance variations, maintaining consistent infusion rates regardless of pump orientation. The non-concentric positioning transforms the gravitational effect from a harmful variable into a compensated parameter.
Solution Approach 2:
The patent changes the mechanical parameters of the piston system by introducing a biasing member that applies a side load, altering the clearance dynamics between the piston and piston chamber. This parameter change (applying lateral force) compensates for orientation-dependent clearance variations, ensuring consistent delivery rates across different gravitational conditions.
2Duration of action of moving object
If reciprocal motion of the actuator is used to deliver and refill the piston chamber, then the pump can function continuously, but wear of pump components increases over time
Solution Approach 1:
The patent modifies the operational parameters of the piston by applying a side load through the biasing member. This changes the friction characteristics and contact dynamics between moving components, reducing wear during reciprocal motion while maintaining continuous pumping capability. The side load optimizes the clearance and contact pressure distribution.
3Adaptability or versatility
If pump orientation affects gravity effects on the actuator, then the pump can be positioned flexibly, but friction and clearance effects vary, affecting infusion consistency
Solution Approach 1:
The non-concentric placement of the biasing member creates an asymmetric force distribution that actively compensates for orientation-dependent gravitational effects. This asymmetric design allows the pump to maintain consistent infusion performance across various positioning scenarios, enhancing both adaptability and operational consistency.
Solution Approach 2:
The patent converts the harmful effect of gravity-induced clearance variations into a beneficial compensation mechanism. The biasing member's side load, which might seem like an additional complexity, actually counteracts gravitational effects, transforming orientation sensitivity into orientation independence.
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
This configuration maintains consistent infusion rates independent of pump orientation and gravity, reducing wear on components and ensuring reliable and consistent delivery of infusion media.
Implementation Method 1
a biasing member, such as a coil spring, disposed non-concentrically with the piston and piston bore, which stabilizes clearances and reduces wear by applying a side load
Implementation Method 2
the pump device has a solenoid coil that can be alternately energized and de-energized to reciprocate the piston within a piston chamber between a forward stroke to deliver infusion media to the subject and a return stroke to refill the piston chamber with infusion media
Data Source
AI summary
An actuator for an infusion drive mechanism comprises a piston defining a first axis and being movable within a passageway of the infusion drive mechanism to convey at least one infusion medium. The passageway defines a longitudinal axis. An armature is connected to the piston and defines at least one cavity configured for disposal of a biasing member engageable with a surface of the infusion drive mechanism to orient the first axis transverse relative to the longitudinal axis. Systems and methods of use are disclosed.