Double-Walled Shear Valve Interstitial Leak Monitoring
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Solution Overview
Problem
In fueling environments, existing double-walled shear valves do not effectively contain leaks at the shear valve point, and lack monitoring for breaches in internal fuel dispenser piping, leading to potential environmental damage and non-detection of leaks.
Innovation Solution
A double-walled contained shear valve design with an inner housing and outer containment housing forming an interstitial space, where a vacuum or pressure can be monitored for leaks, and a vacuum actuator controls the main poppet valve to close the fuel flow path in case of a leak or shear, preventing further leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-walled shear valve is used, then the device complexity is reduced, but the reliability of leak containment deteriorates
Solution Approach 1:
The patent implements a double-walled shear valve where an inner valve body containing the fuel flow path is nested within an outer containment housing. The inner housing has a shearable section for automatic shutdown, while the outer housing provides structural containment and houses the interstitial space for leak detection. This nested configuration enables both shear valve functionality and leak containment without requiring separate independent systems.
Solution Approach 2:
The valve is segmented into distinct functional zones: the inner housing with fuel flow path and shearable section, the interstitial space between inner and outer housings for leak detection, and the outer containment housing providing structural support. This segmentation allows each component to perform its specific function while collectively achieving both shear valve operation and leak containment reliability.
2Reliability
If double-walled piping is implemented, then the reliability of leak containment is improved, but the device complexity increases
Solution Approach 1:
The patent merges the shear valve functionality with the double-walled containment structure into a single integrated component. The inner housing serves as both the shear valve body and the inner wall of the double-walled structure, while the outer housing serves as both the containment structure and the outer wall. This integration eliminates the need for separate shear valve and double-walled piping systems, reducing overall complexity while maintaining reliability.
3Measurement precision
If interstitial space monitoring is added, then the measurement precision of leak detection is improved, but the device complexity increases
Solution Approach 1:
The interstitial space acts as an intermediary zone between the inner fuel-carrying housing and the outer containment housing. By monitoring the pressure or vacuum level in this intermediate space, the system can detect leaks in either the inner or outer housing without requiring direct sensors in the fuel path or complex analysis systems. The interstitial space translates leak conditions into measurable pressure changes.
4Reliability
If a vacuum actuator is added to control the poppet valve, then the reliability of automatic shutdown is improved, but the device complexity increases
Solution Approach 1:
The vacuum actuator is connected to the interstitial space and automatically responds to pressure changes caused by leaks. When a leak is detected through pressure monitoring in the interstitial space, the vacuum actuator self-activates to close the poppet valve, shutting off fuel flow without requiring external control signals or complex control systems. The system uses the leak detection information directly to trigger the shutdown action.
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 double-walled shear valve effectively contains leaks within the interstitial space and automatically shuts off fuel flow to prevent environmental contamination, allowing for continuous monitoring and efficient leak detection.
Implementation Method 1
A vacuum actuator opens and closes a main poppet valve within a fuel flow path of the shear valve in response to vacuum generation and loss in the interstitial space
Implementation Method 2
The interstitial space is monitored for pressure changes. If sufficient pressure changes occur, this is an indication that either the inner piping or the outer piping of the double-walled fuel piping has incurred a leak or breach
Data Source
AI summary
A double-walled contained shear valve comprises of an inner housing forming a fuel flow path, and a containment housing surrounding the inner housing, either partially or wholly, to provide a secondary containment. An interstitial space is formed between the inner housing and the containment housing as a result, and may be placed under a vacuum or pressure level to monitor for leaks. A vacuum actuator coupled to the interstitial space automatically opens and closes the fuel flow path of the shear valve in response to the vacuum level in the interstitial space to prevent leaks to the environment. The shear valve may contain a flange for connection to internal fuel dispenser piping that either does or does not includes interstitial space orifices to couple the shear valve interstitial space to the fuel dispenser piping interstitial space to monitor the vacuum or pressure level in these interstitial spaces as one contiguous space.