HME Device Bypass Mode Switching Mechanism
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Solution Overview
Problem
Existing HME devices for closed breathing circuits in ventilation systems face issues with switching between modes, leading to potential contact between drug aerosols and HME media, increasing flow resistance and risking infection due to contaminated components.
Innovation Solution
An HME device with a housing and switching mechanism that blocks the bypass channel against the HME chamber in bypass mode, preventing fluid contact and using rotatable housing halves and diaphragm configurations to ensure aseptic operation and easy mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the bypass channel is opened to allow fluid bypass passage, then the ease of operation is improved by enabling bypass mode, but the reliability deteriorates due to potential contact between drug aerosol and HME medium
Solution Approach 1:
The device is divided into functionally separate bypass channel and HME chamber, with the bypass channel blocked against the HME chamber in bypass mode to prevent fluid contact. This segmentation ensures that when bypass mode is activated, the bypass channel and HME chamber are separated, allowing mode switching without risk of drug aerosol contacting the HME medium.
2Productivity
If a plunger is used to compress the HME medium, then the productivity is improved by enabling medium compression, but the reliability deteriorates due to liquid escape and infection risk
Solution Approach 1:
The plunger is completely removed from the device. Instead of using a plunger to compress the HME medium, the patent employs a spring mechanism that automatically compresses the HME medium when the cap is closed, eliminating the risk of liquid escape and infection associated with plunger-based compression.
3Ease of operation
If the bypass channel is opened for fluid bypass passage, then the ease of operation is improved, but the object-affected harmful factors worsen due to increased flow resistance from drug aerosol contact
Solution Approach 1:
The bypass channel is segmented and blocked against the HME chamber in bypass mode, creating separate fluid pathways. This prevents drug aerosol from contacting the HME medium, thereby avoiding the increase in flow resistance that would otherwise occur, while still maintaining the ability to switch to bypass mode when needed.
Data Source
AI summary
An HME device, used in a closed breathing circuit of a ventilation system, has a housing with an inlet opening and with an outlet opening, an HME chamber (50a; 50b; 50c; 50d; 50e; 50f; 50g; 50h; 50i) arranged between the inlet opening and the outlet opening for receiving an HME medium and a switching mechanism (70a; 70b; 70c; 70d; 70e; 70f; 70g; 70h; 70i). The HME device can be switched over between an HME mode (M1), in which an HME fluid passage is provided from the inlet opening through the HME chamber to the outlet opening, and a bypass mode (M2), in which a fluid bypass passage is provided from the inlet opening past the HME chamber through a bypass channel (80a; 80b; 80d; 80e; 80f; 80h) in the housing to the outlet opening. The bypass channel is blocked with respect to the HME chamber in the bypass mode (M2).