Humidifier Back-flow Prevention Valve Design
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Solution Overview
Problem
Conventional humidifiers in pressure support systems fail to effectively prevent back-flow of fluid into the pressure support device, particularly due to condensation and tilting, which can damage the device and lead to bacterial growth.
Innovation Solution
A humidifier with a valve arrangement that moves between open and closed positions based on the system's orientation, using a self-regulating flap-like valve element responsive to gas flow pressure and negative pressure during inhalation, and optionally biased with a counterweight and magnetic damping, to block the inlet and prevent fluid back-flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a snorkel-type inlet configuration is used to minimize water backsplash, then water entry due to tilting is reduced, but water entry due to condensation and rainout is not prevented
Solution Approach 1:
A check valve is introduced as an intermediary component between the pressure support device outlet and the humidification chamber inlet. This valve acts as a mediator that allows gas flow in the forward direction while blocking fluid back-flow, thereby addressing both water backsplash and condensation/rainout issues that the snorkel configuration alone could not prevent.
Solution Approach 2:
The check valve is designed to operate automatically based on pressure differential without external control. During normal operation, positive pressure from the pressure support device opens the valve automatically. During back-flow conditions (condensation, rainout, or tilting), the pressure reversal automatically closes the valve, providing self-regulating protection against all back-flow mechanisms.
2Stability of the object's composition
If the humidification chamber is rigidly coupled directly to the pressure support device outlet, then the connection is secure, but fluid back-flow is exacerbated due to direct and close connection
Solution Approach 1:
The check valve serves as a protective intermediary component installed in the direct connection path between the pressure support device outlet and humidification chamber inlet. This allows the rigid coupling to be maintained for stability while the valve blocks the harmful fluid back-flow that would otherwise occur through the direct connection.
3Reliability
If a valve is added to prevent back-flow, then device safety is improved, but device complexity increases
Solution Approach 1:
The check valve is designed as a passive, self-operating component that requires no external power, control signals, or complex actuation mechanisms. It automatically responds to pressure differentials, opening during normal operation and closing during back-flow conditions. This self-service operation maintains high reliability while minimizing the addition of complexity to the overall system.
Solution Approach 2:
The check valve is implemented as a simple, inexpensive mechanical component that can be easily replaced if needed. This approach prioritizes system safety and reliability over minimizing component count, using a straightforward valve design rather than attempting complex back-flow prevention mechanisms.
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
Effectively prevents fluid back-flow into the pressure support device, ensuring device safety and minimizing bacterial growth by maintaining a closed position during reduced pressure conditions and tilting, while allowing unobstructed gas flow during normal operation.
Implementation Method 1
a self-regulating flap-like valve element responsive to gas flow pressure
Implementation Method 2
magnetic damping
Implementation Method 3
optionally biased with a counterweight and magnetic damping
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A humidifier for use with a pressure support system. The humidifier includes a body (44, 302, 442, 910) having an inlet (36, 308, 448, 914), a fluid holding chamber (46, 318, 454, 912), and an outlet (40, 916). The inlet is positioned upstream and in fluid communication with the fluid holding chamber. The outlet is positioned downstream of and in fluid communication with the fluid holding chamber. A back-flow preventing valve (60, 160, 260, 304, 334, 400, 444, 500, 600, 700, 760, 902, 930, 958, 970, 980) is positioned upstream of the fluid chamber. The back-flow preventing valve is movable between an open position, in which the inlet is unblocked, and a closed position in which the inlet is blocked. In the closed position, the back-flow preventing valve prevents fluid, fluid vapor, or both from entering the pressure support via the inlet to the humidifier.