Hydraulically Expandable Excess Flow Valve for Gas Service Lines
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Solution Overview
Problem
Existing pipeline excess flow valves (EFVs) require disruptive and costly installation methods, including digging and cutting of service lines, due to challenges in anchoring the device without damaging the interior piping and unpredictable geometry of fittings.
Innovation Solution
A hydraulically expandable EFV with compatible installation equipment that allows for secure anchoring within the existing service line using a hydraulic pump, flexible water line, and mandrel, enabling installation without digging by expanding to fit snugly inside the service line while maintaining the service line pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional EFV installation methods are used (digging, cutting service line), then secure anchoring of the valve is achieved, but installation becomes disruptive, costly, and time-consuming
Solution Approach 1:
The EFV is divided into two functional segments: a collapsible body portion that can be inserted through the service line in a compressed state, and an expandable anchoring portion that expands after insertion to secure the valve. This segmentation allows the valve to be installed without digging by separating the insertion phase from the anchoring phase.
Solution Approach 2:
The EFV transitions from a static, rigid structure to a dynamic, adaptable structure through its collapsible and expandable features. The valve body collapses to fit through the service line during installation, then expands to anchor securely against the service line interior wall, providing adaptability to the installation process.
2Reliability
If the service line is cut for EFV installation, then the valve can be anchored securely, but service disruption and installation cost increase
Solution Approach 1:
The EFV is inserted into the existing service line like a nested doll, with the collapsible valve body fitting inside the service line conduit. This nesting approach allows the valve to be installed within the existing infrastructure without cutting or modifying the service line, simplifying the installation process.
Solution Approach 2:
The expandable anchoring portion acts as an intermediary between the EFV and the service line interior wall. It provides a secure connection without requiring direct mechanical fastening or modification of the service line, using expansion force to create friction-based anchoring.
3Reliability
If the EFV is expanded to anchor securely inside the service line, then reliable anchoring is achieved, but the risk of damaging the service line increases
Solution Approach 1:
The EFV applies expansion force locally at the anchoring portion rather than uniformly across the entire valve body. This localized expansion concentrates the anchoring force at specific points where the expandable elements contact the service line interior wall, providing secure anchoring while minimizing stress on the service line.
Solution Approach 2:
The EFV changes its physical parameters (volume, shape, density) through controlled expansion. The collapsible body expands from a compressed insertion state to an expanded operational state, increasing its diameter to contact and anchor against the service line interior wall while maintaining material integrity.
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
Enables retrofitting of EFVs with minimal disruption, allowing secure anchoring without damaging the service piping, reducing installation time and costs, and ensuring safety by preventing gas leaks from ruptured lines.
Implementation Method 1
a hydraulically expandable EFV with compatible installation equipment that allows for secure anchoring within the existing service line using a hydraulic pump
Implementation Method 2
the stem of a conventional EFV such as that shown in U.S. Pat. No. 5,551,476 is spring biased opposite to the direction of gas flow
Implementation Method 3
When the flow is excessive such as when the service line ruptures downstream of the EFV, the forces from the flowing fluid overcome the spring bias and the poppet closes against the seat
Data Source
AI summary
An excess flow valve (EFV) for installation in a service line of natural gas distribution system serving an existing structure. The EFV has a cylindrical housing having a first length and a second length and a through hole therethrough for passage of gas. The EFV 11 engaged in the through hole of the first length and the second length has an expandable wall which can be expanded and fixed in said service line.