Pneumatic Port Shield Tortuous Pathway Particle Ingestion
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Solution Overview
Problem
Pneumatic air valves and actuators in aerospace applications face performance issues due to ingestion of external particles through unfiltered ambient ports, which clog mechanical clearances, but filtration constricts airflow and is not considered a reasonable solution.
Innovation Solution
A port shield with a sheet and connecting member creates a tortuous air pathway to prevent particle ingestion without constricting airflow, comprising a compliant material like rubber or fiberglass fabric, easily assembled and lightweight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filters are incorporated on ambient ports to prevent particle ingestion, then reliability is improved, but device complexity and airflow restriction increase
Solution Approach 1:
A port shield is introduced as an intermediary component between the external environment and the ambient port. This shield creates a tortuous air pathway that prevents particles from directly entering the actuator while allowing ambient air to pass through. The shield acts as a physical barrier that redirects airflow without constricting it, thereby protecting internal components from contamination without requiring complex filtration systems.
Solution Approach 2:
The port shield extends outward from the ambient port into the external environment, creating a three-dimensional protective structure. By adding this spatial dimension, the shield intercepts particles before they can reach the port opening and establishes a tortuous airflow path that naturally filters contaminants while maintaining unrestricted air flow to the actuator.
2Reliability
If filters are used on ambient ports, then particle ingestion is prevented, but airflow is constricted impacting reference pressure
Solution Approach 1:
The port shield serves as a mediator that separates the protection function from the airflow function. It provides contamination protection through its physical barrier and tortuous pathway design while simultaneously maintaining unrestricted airflow by extending into the external environment rather than blocking the port opening. This allows ambient air to flow freely past the shield and into the actuator without pressure loss.
Solution Approach 2:
By extending the protection structure outward from the port plane into the external environment, the shield creates a volumetric protective zone. This dimensional approach allows airflow to continue unobstructed through the ambient port while particles in the external environment are intercepted by the shield's extended structure, preventing them from reaching the port opening.
3Measurement precision
If tight control tolerances and small mechanical clearances are used for performance accuracy, then measurement precision is improved, but susceptibility to particle clogging increases
Solution Approach 1:
The port shield acts as a protective intermediary that shields the small mechanical clearances and tight tolerances from particle contamination. By creating a tortuous airflow path and physical barrier, it prevents particles from reaching the sensitive internal components with small clearances, thereby protecting the precision elements from clogging while allowing the actuator to maintain its high performance accuracy.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A port shield (24) for a pneumatic actuator (8) with a casing wall (20) includes a sheet (30) and a connecting member (32). The sheet (30) includes an outer face (34) disposed opposite an inner face (36), a first end (38) disposed opposite a second end (40), and a first edge (42) disposed opposite a second edge (44). The sheet (30) also includes a bend (50) formed in the sheet (30) between the first edge (42) and the second edge (44), wherein the bend (50) extends from the first end (38) to the second end (40) and forms an apex (52) on the outer face (34) of the sheet (30). The connecting member (32) extends from the sheet (30) and is configured to connect the sheet (30) to an outer side of the casing wall (20) of the pneumatic actuator (8).