Hydraulically Expandable Excess Flow Valve for Gas Service Lines
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Solution Overview
Problem
Conventional excess flow valves (EFVs) are difficult to install in existing gas service lines without disrupting the service, as they require digging and reducing pressure to zero, and anchoring within the service piping is a significant challenge due to unpredictable geometry and the need to avoid damaging the interior walls.
Innovation Solution
A hydraulically expandable EFV with a cylindrical housing and an expandable tubular wall that can be expanded within the service line using a mandrel, hydraulic pump, and flexible water line to anchor securely without damaging the piping, allowing installation without digging and maintaining service line pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional EFV installation methods are used, then the EFV can be installed in the service line, but digging is required and service pressure must be reduced to zero, causing disruption and high cost
Solution Approach 1:
The expandable tubular wall is pre-installed in a compressed state within the service line before pressure reduction. This preliminary action allows the EFV to be installed without digging and without reducing service pressure, as the expansion occurs after insertion when the valve is already in position
Solution Approach 2:
The tubular wall transitions from a static compressed state during insertion to a dynamic expanded state after installation. This dynamic transformation allows the same structure to serve dual purposes: enabling easy insertion in a compressed form and providing secure anchoring when expanded, thereby eliminating the need for digging and pressure reduction
2Reliability
If anchoring methods are used that secure the EFV in the service line, then the EFV remains fixed, but the interior wall of the service piping may be damaged
Solution Approach 1:
The tubular wall is made of expandable material that can be inserted in a compressed state and then expanded to contact the service line interior wall. This flexible shell approach allows the anchoring structure to adapt to the existing pipe geometry without requiring rigid anchoring elements that could damage the piping
Solution Approach 2:
The tubular wall undergoes a parameter change from a small diameter compressed state during insertion to a larger diameter expanded state for anchoring. This parameter transformation allows the EFV to be installed without digging and anchored securely without damaging the service piping interior wall
3Reliability
If the service line is cut for EFV installation, then the EFV can be installed, but the installation becomes expensive and time-consuming
Solution Approach 1:
The expandable tubular wall is pre-installed in a compressed state within the service line before pressure reduction. This preliminary action allows the EFV to be installed without digging and without reducing service pressure, as the expansion occurs after insertion when the valve is already in position
Solution Approach 2:
The compressed tubular wall is nested within the service line in a compact form, allowing insertion through the existing piping without cutting. After insertion, the tubular wall expands from its nested compressed state to its full anchoring diameter, securing the EFV in place without requiring service line interruption
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 EFVs in existing gas service lines with minimal disruption, ensuring secure anchoring and sealing without damaging the service piping, allowing for continuous gas supply during installation.
Implementation Method 1
an expandable tubular wall forms a portion of the second length of the cylindrical housing, wherein the expandable tubular wall being adapted to and capable of anchoring the EFV and the cylindrical housing within the service line when the expandable tubular wall has been expanded within the service line
Implementation Method 2
the installation equipment comprises a mandrel, fluid line and hydraulic pump which are all engaged together to deliver fluid under pressure to said mandrel
Implementation Method 3
the stem of a conventional EFV such as that shown in USP 5,551,476 is spring biased opposite to the direction of gas flow. Under normal conditions the poppet on the stem is held away from a valve seat by the bias spring
Implementation Method 4
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, shutting off the flow
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to an excess flow valve (EFV) (1) adapted to be installed in a service line of a natural gas distribution system serving an existing structure, said EFV comprising: a cylindrical housing (10) having a first length (6) and a second length (8) and a through hole (11) therethrough for passage of gas; the EFV being engaged in said through hole of said first length; and an expandable wall (14) forming part of said second length; wherein said expandable wall can be expanded and fixed in said service line.