Grooved Actuator Piston for Infusion Device Refill
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Infusion devices face challenges in efficiently cleaning protein deposits from the fluid paths, leading to restricted fluid flow and potential device jamming, as existing rinse procedures take longer than desired due to the tight annulus between the actuator piston and piston cylinder, causing prolonged refill times and reduced stroking frequency.
Innovation Solution
The implementation of a grooved actuator piston with helical grooves on its surface, which enhances fluid flow by ensuring a path for rinsing agents to reach deposits even when the device is jammed, significantly shortening refill times and increasing infusion rates by transitioning flow from laminar to turbulent, thus facilitating effective cleaning and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a tight annulus is used between the actuator piston and piston cylinder wall, then the device structure is compact and sealing is improved, but the refill time increases and fluid flow is restricted
Solution Approach 1:
The piston surface is segmented into multiple grooves that divide the refilling flow path into several parallel channels. This segmentation increases the total effective flow area while maintaining the tight annular clearance for sealing, allowing faster refilling without compromising the compact design
Solution Approach 2:
The grooved piston surface creates a porous-like structure with multiple flow paths through the grooves. This increases the effective permeability of the piston surface to fluid flow, enabling faster refilling while maintaining the tight overall clearance for proper sealing
2Reliability
If a tight annulus is used between the actuator piston and piston cylinder wall, then sealing is improved, but protein deposit buildup restricts fluid flow and may cause device jamming
Solution Approach 1:
The grooves extract or remove the problematic tight annular space where protein deposits accumulate, replacing it with open grooved channels that are resistant to clogging. This maintains sealing through the groove geometry while eliminating the narrow clearance that traps deposits
Solution Approach 2:
Instead of relying on a tight annular clearance for both sealing and flow, the invention inverts the approach by using open grooves that provide flow paths resistant to deposit buildup, while maintaining sealing through the groove structure itself rather than through clearance tightness
3Quantity of substance
If the refill stroke is slowed to allow complete refilling, then the piston chamber is fully refilled, but the stroking frequency decreases and infusion rate is reduced
Solution Approach 1:
The refilling process is segmented into multiple parallel flow paths through the grooves, allowing simultaneous refilling through several channels. This increases the total refilling rate so that complete refilling occurs faster, maintaining full piston chamber volume while increasing stroking frequency and infusion rate
Solution Approach 2:
The groove geometry parameters (depth, width, pitch) are optimized to change the flow characteristics, increasing the effective flow area and reducing flow resistance. This allows the piston chamber to refill completely in less time, enabling faster stroking cycles and higher infusion rates
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 grooved actuator piston design reduces refill time by up to 75% compared to smooth actuators, allowing for increased infusion rates and ensuring the device can operate efficiently despite protein deposits, enabling faster delivery of therapy drugs to patients.
Implementation Method 1
when the solenoid is energized, magnetic flux causes the actuator to move very quickly (i.e. in the order of 2-3 milliseconds) until it reaches a stop member
Implementation Method 2
When the solenoid is de-energized, the lack of magnetic flux allows the actuator to return to its original position under the force of a spring
Implementation Method 3
The reduced pressure in the piston chamber causes infusion media to flow from a reservoir through an annulus between the actuator piston and the piston cylinder wall to refill the piston chamber
Implementation Method 4
significantly shortening refill times and increasing infusion rates by transitioning flow from laminar to turbulent
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An apparatus for delivering a fluid includes a housing (14), an inlet (22) in the housing (14) for receiving the fluid, and an outlet (24) in the housing (14) for discharging the fluid. A piston channel (38) is provided within the housing (14) through which the fluid flows from the inlet (22) to the outlet (24). An actuator (58) is positioned within the housing (14) and is moveable between a retracted position and a forward position, the actuator (58) defining a piston chamber (100) for storing fluid received through the inlet (22) when the actuator (58) is in the retracted position and for driving the fluid stored in the piston chamber (100) toward the outlet (24) when the actuator (58) transitions from the retracted position to the forward position. The actuator (58) includes an armature (60) and a piston (62) coupled to the armature (60) and moveable within the piston channel (38). The piston (62) is provided with a groove (64) in an outer surface for conducting fluid from the inlet (22) to the outlet (24).