Dual-Piston Pump Sub-Assembly Using SMA Actuation for Precise Dosing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional motor-driven medicament delivery devices are heavy, noisy, and inefficient, necessitating a more efficient and lightweight solution for delivering precise volumes of medicaments.
Innovation Solution
A sub-assembly of a pump device utilizing a shape-memory alloy actuator intermittently heated by a power source to control the movement of pistons within a chamber, enabling precise medicament delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional motor-driven systems are used to deliver medicaments, then precise volume delivery can be achieved, but the device becomes heavy, noisy, and consumes excessive power
Solution Approach 1:
The patent replaces the conventional motor-driven mechanical pump system with a shape-memory alloy (SMA) actuated piston system. The SMA material undergoes phase transformation when exposed to specific temperatures, causing it to change shape and directly drive the piston to deliver medicament. This substitution eliminates the need for heavy motors, gears, and other mechanical drive components, thereby significantly reducing device weight while maintaining precise volume delivery control through temperature-based actuation.
Solution Approach 2:
The invention utilizes temperature as the controlling parameter to actuate the SMA material. By changing the temperature of the SMA (e.g., through exposure to body temperature or controlled heating), the material undergoes phase transformation from martensite to austenite, causing it to change shape and drive the piston. This parameter-based control allows for precise and repeatable volume delivery without requiring heavy mechanical drive systems.
2Productivity
If conventional motor-driven systems are used, then medicament delivery is achieved, but the device produces significant noise
Solution Approach 1:
The patent eliminates the motor-driven mechanical transmission system that generates noise by replacing it with a direct thermal actuation system. The shape-memory alloy responds directly to temperature changes with smooth, controlled shape transformation that drives the piston without mechanical gears, belts, or motors. This substitution removes the primary sources of mechanical noise while maintaining effective medicament delivery capability.
3Productivity
If conventional electric motors are used for pump operation, then medicament can be delivered, but the power consumption is significant and continuous
Solution Approach 1:
The SMA actuation system operates on a periodic basis, where the SMA material is heated to trigger phase transformation and piston movement, then cools down to reset the cycle. This periodic thermal actuation eliminates the need for continuous motor operation, significantly reducing average power consumption while maintaining effective medicament delivery during the active phases of the cycle.
Solution Approach 2:
The replacement of the motor-driven system with a thermally actuated SMA system eliminates continuous electrical power consumption. The SMA material utilizes thermal energy from the environment or mild heating to drive the pump action, which is a more efficient energy utilization pattern that consumes power only during the actuation phase rather than continuously.
4Weight of moving object
If a shape-memory alloy actuator is used, then device weight and noise are reduced, but the device complexity increases due to the actuation assembly
Solution Approach 1:
The patent merges the actuator and piston into an integrated assembly where the SMA material is directly coupled to the piston mechanism. This integration eliminates the need for separate drive shafts, gears, belts, and other mechanical transmission components. The SMA actuator assembly combines the actuation function and piston driving function into a single unified structure, reducing overall device complexity despite the advanced material used.
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 solution provides a lightweight, quiet, and efficient mechanism for delivering precise volumes of medicaments, suitable for various medicament delivery devices including auto-injectors and infusion pumps.
Implementation Method 1
an actuator made of a shape-memory alloy configured to be intermittently heated by a power source
Implementation Method 2
actuator made of a shape-memory alloy configured to be intermittently heated by a power source
Data Source
AI summary
The present disclosure provides a sub-assembly of a pump device comprising a housing comprising a chamber extending along a longitudinal axis. The chamber comprises an inlet and an outlet. Both the inlet and the outlet are open in a direction transverse to the longitudinal axis. The inlet is configured to be fluidly connected to a medicament container. The housing comprises a wall extending in the direction transverse to the longitudinal axis. The sub-assembly of the pump device further comprises a first piston and a second piston. Both the first piston and the second piston are at least partially arranged within the chamber and fluid-tightly engaged with the chamber between the inlet of the chamber and the outlet of the chamber. The first piston is lined up with the second piston along the longitudinal axis. The sub-assembly of the pump device further comprises a control mechanism configured to cause the first piston and the second piston to be selectively moved together or moved relative to one another.