Dry-Break Refueling Coupling for Pressure and Gravity Filling
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Solution Overview
Problem
Existing refueling couplings do not efficiently facilitate both pressure and gravity refueling without fuel leakage, particularly in scenarios where the transition between refueling methods is not seamlessly managed.
Innovation Solution
A refueling coupling design featuring a displaceable dry-break member with a manually removable subsidiary member for gravity refueling, utilizing a bayonet fitting or screw threads, and a tether to prevent loss, ensuring fluid-tight sealing and easy manual handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a subsidiary displaceable member is used to close the aperture for gravity refueling, then fuel leakage is prevented during pressure refueling, but the device complexity increases due to additional components
Solution Approach 1:
The subsidiary displaceable member is integrated with the dry-break member through a pivotal connection, allowing both components to work together as a unified sealing system. The member is carried by the dry-break member and pivots on a pin, combining the sealing functions of both elements while reducing overall system complexity compared to separate independent components.
Solution Approach 2:
The subsidiary displaceable member serves multiple functions: it closes the aperture during pressure refueling to prevent fuel leakage, and is displaceable to allow gravity refueling when needed. This multi-functional design eliminates the need for separate mechanisms for each refueling mode, thereby reducing device complexity while maintaining reliability.
2Ease of operation
If the subsidiary displaceable member is pivotally displaceable with a return spring, then automatic closure is achieved after gravity refueling, but the device complexity increases
Solution Approach 1:
The return spring automatically returns the subsidiary displaceable member to its closed position after gravity refueling without requiring manual intervention. The spring is compressed when the member is displaced for gravity refueling and automatically pushes it back to the sealing position, making the system self-servicing and eliminating the need for additional actuation mechanisms.
Solution Approach 2:
The subsidiary member exhibits periodic motion: it is displaced during gravity refueling and automatically returns to its closed position via the spring. This periodic action alternates between open and closed states based on refueling mode, simplifying operation while using a straightforward spring mechanism rather than complex control systems.
3Adaptability or versatility
If an aperture is provided in the dry-break member for gravity refueling, then gravity refueling capability is enabled, but fuel leakage risk increases during pressure refueling
Solution Approach 1:
The subsidiary displaceable member is pre-positioned to close the aperture before pressure refueling begins. This preliminary closure action prevents fuel leakage through the aperture during pressure refueling, while still allowing the aperture to be opened when gravity refueling is required. The member is normally closed and only opened when needed.
Solution Approach 2:
The subsidiary displaceable member is designed to be dynamically displaceable rather than fixed. It can pivot between closed and open positions depending on the refueling mode required. This dynamic capability allows the system to adapt to different refueling methods while maintaining fuel containment when the aperture is not in use.
Data Source
AI summary
A refueling coupling has an annular fitting 101 having a bore 102, bayonet lugs 103 and slots 104 suiting it for connection to a pressure filling nozzle. A flange 122, drilled with screw holes for securement to a fuel tank (not shown), extends out from the fitting 101. Also not shown for the sake of clarity is a tube extending own from the flange. Rods extend down from the flange 122 to a spider 125, with springs bearing upwards onto the underside of a dry-break member 105, through which the rods extend. The rods, springs and spider are within the non-shown tube.On attaching and opening of a pressure filling nozzle to the coupling, the dry-break member 105 is displaced resiliently inwards fuel can flow past this member and into the tank.The dry-break member has a central aperture 111, normally closed by a plug 112, which is threaded externally 114 and carries an O-ring seal 115 above the thread. The central aperture has a plain bore orifice 116 and is threaded 117 below the plain bore. Thus, when the plug is screwed in, the dry-break member is fluid tight as normal.