Spring-Activated Latch for Anti-Free Flow in Infusion Pumps
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Solution Overview
Problem
Existing anti-free flow mechanisms in infusion pumps are inadequate in ensuring reliable prevention of fluid flow when the pump is being set up, particularly in passive mechanical interfaces that accommodate flexible infusion tubes.
Innovation Solution
A passive mechanical interface with a spring-activated latch that automatically switches between closed and open configurations based on proper mounting, allowing for uni-directional or bi-directional flow, and can be manually or automatically controlled to prevent fluid flow when not mounted correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive mechanical interface is used to accommodate the flexible infusion tube, then the device structure is simplified, but the reliability of anti-free flow function deteriorates
Solution Approach 1:
The spring-activated latch mechanism automatically detects whether the mechanical interface is properly mounted and self-regulates the valve state accordingly. When the interface is improperly mounted, the springs remain uncompressed and the latch automatically closes to prevent free flow. When properly mounted, the compression of springs actuates the latch to open the flow path, eliminating the need for manual intervention or complex control systems.
Solution Approach 2:
The latch mechanism is pre-configured in a closed position by the spring force before mounting occurs. This preliminary closed state ensures that if mounting is not completed or is improper, the anti-free flow function is already activated. The system performs the safety action in advance, ready to prevent free flow until proper mounting is confirmed.
2Reliability
If a spring-activated latch is incorporated to provide automatic anti-free flow control, then the reliability of flow control is improved, but the device complexity increases
Solution Approach 1:
The anti-free flow valve mechanism is merged with the mechanical interface components rather than being separate. The latch, springs, and interface elements are integrated into a unified assembly where the valve function is embedded within the mounting structure itself, reducing overall device complexity while maintaining reliable flow control.
Solution Approach 2:
Complex electronic sensors, motors, or software control systems are replaced with a purely mechanical spring-latch mechanism. The spring-latch system uses mechanical force transmission and geometric relationships to achieve automatic flow control, eliminating the need for complex electronic or software-based control systems.
3Ease of operation
If the latch is designed to automatically switch configurations based on mounting status, then the ease of operation is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The system uses changes in mechanical parameters (spring compression distance, latch position, component engagement depth) to detect mounting status and trigger the appropriate valve state. By carefully selecting spring constants, compression distances, and geometric parameters, the system achieves reliable automatic switching that is tolerant of normal manufacturing variations while maintaining ease of operation.
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 mechanism effectively prevents fluid flow when not properly mounted, ensuring safety and reliability by automatically switching to a closed configuration when the interface is not correctly secured, and allowing free flow when properly mounted, facilitating easy operation with minimal user intervention.
Implementation Method 1
an anti-free flow valve (AFFV) which is a spring-activated latch incorporated within the MS
Data Source
AI summary
The present invention discloses an anti-free flow mechanism for a finger-type peristaltic infusion pump (DDS) and methods for avoiding anti-free-flow. The mechanism comprises: a passive mechanical interface (MS) which integrally accommodates a portion of the flexible infusion tube, and an anti-free flow valve (AFFV) which is a spring-activated latch, which is incorporated within said MS. The maneuverable latch is secured in the MS either in CLOSED or OPEN configurations: in its CLOSED configuration no flow is provided, and in its OPEN configuration, a free flow is facilitated. Said anti-free flow mechanism is configured in a manner such that when the MS is not properly mounted in the DDS, said AFFV is automatically actuated via one or more integrated springs, to its CLOSED configuration. When the MS is properly mounted in the DDS, said latch is adapted to be automatically switched to the OPEN configuration.