Flared Nozzle and Vacuum for Heat Shield Sealant Injection
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Solution Overview
Problem
The current method of filling gaps in the Orion Crew Exploration Vehicle's heat shield with a thixotropic sealant using a metal syringe needle is extremely slow, taking over 7500 minutes to fill 3000 inches of gaps, which affects production schedules and increases costs due to manual labor.
Innovation Solution
A method involving a flared dispensing nozzle and vacuum application to inject sealant into covered gaps, allowing for faster filling and sealing, with the nozzle's flared end providing a larger dispensing area and the vacuum removing air voids, significantly increasing the sealant flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a metal syringe needle is used to inject sealant into gaps, then the sealant can be injected into narrow deep gaps, but the filling speed is extremely slow (0.4 inches per minute)
Solution Approach 1:
The patent applies pneumatic pressure through a pneumatic extrusion gun to force sealant through the dispensing nozzle at high speed. The pressurized air system overcomes the natural flow restrictions and enables rapid filling of narrow deep gaps, achieving speeds up to 2 inches per minute compared to 0.4 inches per minute with manual syringe injection.
Solution Approach 2:
The patent changes the physical parameters of the dispensing system by using a flared dispensing nozzle instead of a narrow needle orifice. The flared geometry increases the effective dispensing area and reduces flow resistance, while pneumatic pressure changes the driving force parameter from manual to mechanical, dramatically increasing dispensing speed.
2Productivity
If manual labor is used to fill gaps, then precise control of sealant application is achieved, but production time and costs increase significantly (over 7500 minutes for 3000 inches)
Solution Approach 1:
The pneumatic extrusion gun system replaces manual syringe injection with automated pneumatic actuation. The pressurized air system provides consistent, high-speed sealant delivery throughout the 3000 inches of gaps, reducing total filling time from over 7500 minutes to approximately 1500 minutes (2.5x productivity improvement).
Solution Approach 2:
The system uses pressurized air that is already available in the manufacturing environment to drive the sealant injection process. The pneumatic system self-regulates the flow and pressure, reducing the need for manual intervention and monitoring while maintaining consistent application quality across all gaps.
3Speed
If a narrow needle orifice is used to maintain precision, then sealant flow control is restricted, but the filling speed decreases to 0.4 inches per minute
Solution Approach 1:
The patent fundamentally changes the orifice geometry from a narrow needle (18 gage) to a flared dispensing nozzle with a significantly larger opening. This geometric parameter change increases the maximum flow volume capability while the pneumatic pressure system provides the necessary force to control and direct the higher volume flow into the narrow gaps at accelerated speeds.
Solution Approach 2:
The pneumatic pressure system compensates for the larger nozzle opening by providing controlled pressurization. The pressurized air forces the sealant through the flared nozzle at high velocity, ensuring that the increased flow capacity is effectively utilized to fill gaps faster while maintaining precise delivery through pressure regulation.
4Loss of time
If traditional injection methods are used, then equipment simplicity is maintained, but the process takes over 7500 minutes to complete 3000 inches of gaps
Solution Approach 1:
The patent introduces a pneumatic extrusion gun system that uses pressurized air to drive sealant injection. This pneumatic system reduces total filling time from over 7500 minutes to approximately 1500 minutes. The system integrates a dispensing nozzle, pressurized air supply, and control mechanism, representing a moderate increase in device complexity that is justified by the 5x reduction in processing time.
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 method enables the sealant to be dispensed at a rate of about two inches per minute, filling gaps much faster than traditional methods and producing a virtually void-free seal, improving production efficiency and reducing costs.
Implementation Method 1
applying a vacuum to the covered gap at a second location
Implementation Method 2
The heat-absorbing elements are separated by a gap having a nominal thickness of 0.080±0.020 inches. The gaps are filled with a thixotropic sealant
Data Source
AI summary
A method of applying sealant to a narrow, deep gap in a surface includes covering the gap to form a covered channel, inserting a flared end of a dispensing nozzle into the covered gap at a first location, and applying a vacuum to the covered gap at a second location while using the nozzle to inject the sealant into the gap at the first location. This method may be used to seal gaps between ablative elements of a heat shield.