Autoclavable Switch Assembly Venting
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Solution Overview
Problem
The existing autoclavable switch assemblies for surgical remote controls face issues with air trapping and contamination, leading to potential failures of the printed circuit board circuitry due to vent holes that allow contaminants to enter and cause shorts or other damage during repeated autoclave cycles.
Innovation Solution
The design minimizes vent holes by creating a tortuous airflow channel that traps contaminants, with the circuitry confined to one side of the printed circuit board and using a spacer and vent layer configuration to prevent direct contact with contaminants, allowing the assembly to withstand multiple autoclave cycles without failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vent holes are provided to allow air flow from switch cavities, then air venting is achieved, but contaminants can enter via vent holes and contact circuitry causing shorts or failures
Solution Approach 1:
A hydrophobic coating is applied to the interior surfaces of the vent holes to create a mediator that repels water and contaminants while allowing air to pass through. This coating acts as an intermediary barrier that maintains the venting function while blocking harmful contaminants from reaching the circuitry.
Solution Approach 2:
The vent holes are treated with a hydrophobic coating that creates an inert-like environment resistant to water and contaminant penetration. This coating establishes a protective atmosphere within the vent channels that prevents harmful substances from contacting the circuitry while maintaining air flow for switch operation.
2Ease of operation
If multiple vent holes are provided for air flow, then air venting is improved, but the number of potential contamination paths increases
Solution Approach 1:
The hydrophobic coating serves as a mediator on all vent hole surfaces, allowing multiple vent holes to be provided for effective air venting while each hole's coated interior prevents contaminant entry. The coating enables the system to have multiple ventilation paths without proportionally increasing contamination risk.
3Reliability
If the remote control is sterilized by autoclaving, then sterilization is achieved, but air becomes trapped in switch cavities and contaminants can enter during operation
Solution Approach 1:
The hydrophobic coating on vent hole interiors acts as a mediator that allows air to vent freely during switch operation while blocking water and contaminants. This enables the remote control to be autoclaved for sterilization and then operate normally with proper air venting without contaminant ingress.
Solution Approach 2:
The hydrophobic coating is applied in advance to prevent contaminant entry before it can occur during operation. This preliminary protective action ensures that when the device is autoclaved and subsequently used, air can vent properly while contaminants are blocked from entering through the vent holes.
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
This configuration effectively limits exposure of the printed circuit board circuitry to contaminants, extending the device's lifespan through the commercially acceptable number of autoclave cycles by preventing direct contact and trapping contaminants within the tortuous channels, thus ensuring reliable operation.
Implementation Method 1
The vent holes may be treated with a hydrophobic coating to prevent water and contaminants from entering through the vent holes
Implementation Method 2
The remote controls are sterilized by autoclaving after each use
Data Source
AI summary
A device includes a printed circuit board having a first surface and a second surface. The printed circuit board defines an opening therethrough from the first surface to the second surface and a circuit formed on the first surface of the printed circuit board with no portion of the circuit intersecting the opening. The second surface of the printed circuit board at least partially bounds a first channel in fluid communication with the opening. A method of venting includes displacing air within a cavity of a switch by moving the air through one or more channels formed in a layer defining cut-outs in fluid communication with the cavity. The air is moved through an opening formed in a printed circuit board. The layer is positioned at a first side of the printed circuit board. In addition, the method includes moving the air through a venting channel positioned at a second, opposite side of the printed circuit board and into the surrounding environment.