Expansion Plug Sealing for Live Service Tee Replacement

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Solution Overview

Problem

Existing methods for replacing service tees in pressurized piping systems, such as gas mains, often result in gas leakage during replacement, posing safety risks or requiring shutdowns to prevent gas escape, especially due to incorrect installation, tampering, or manufacturing defects.

Innovation Solution

An expansion plug system with a shaft, collars, expanding structures, and an expansion tool that allows for sealing a transverse hole in a pipe without shutting down gas flow by expanding elastomeric and wedge components to secure the plug in place, using a two-part expansion tool for controlled expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If service tee replacement is done on the fly without shutdown, then productivity is improved, but gas leakage occurs causing safety hazards

Engineering Contradiction:

Improveservice tee replacement speedVSAvoidgas leakage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The expansion plug is inserted into the transverse hole before the service tee is removed, establishing a seal in advance to prevent gas leakage during the replacement operation. This preliminary sealing action allows the service tee to be replaced without shutting down gas flow.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The expansion plug acts as an intermediary device between the transverse hole and the replacement service tee. It provides a temporary sealing mechanism that bridges the gap created when the service tee is removed, preventing gas escape until the new service tee is installed and sealed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If gas flow is shut down during service tee replacement, then gas leakage is prevented, but productivity decreases

Engineering Contradiction:

Improvegas leakage preventionVSAvoidservice tee replacement efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The expansion plug is installed and sealed in the transverse hole before the service tee replacement begins, preparing the system in advance to maintain gas flow continuity. This eliminates the need for shutdown while preventing gas leakage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The expansion plug maintains continuous gas flow through the gas main during the service tee replacement operation. By establishing a seal that allows gas to bypass the work area, the useful action of gas transport continues uninterrupted throughout the replacement process.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If expansion plug uses single-stage expansion, then device complexity is reduced, but sealing reliability is insufficient for high pressure

Engineering Contradiction:

Improveexpansion mechanism structureVSAvoidsealing performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The expansion mechanism is divided into two separate expanding structures: a first expanding structure with elastomeric elements for initial sealing, and a second expanding structure with wedge elements for enhanced high-pressure sealing. This segmentation allows each structure to be optimized for its specific function while working together to provide reliable sealing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first expanding structure with elastomeric elements performs preliminary sealing at lower expansion forces, creating an initial seal. Subsequently, the second expanding structure with wedge elements is activated to provide enhanced sealing capability for high-pressure conditions, building upon the preliminary seal.

Inventive Principle:

Principle #10Preliminary 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

Enables safe and efficient replacement of service tees by preventing gas leakage during installation, ensuring continuous gas flow and safety by maintaining a sealed connection without the need for shutdowns.

Implementation Method 1

The first expanding structure includes an elastomeric element having an annular configuration and configured to expand radially when it is compressed axially

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The second expanding structure includes a wedge having a central opening disposed over the shank, a pair of opposed ears which surround the shank, and a circumferential spring which biases the ears together, wherein the ears are configured to be pushed apart radially as the wedge moves toward the head

Methodology Applied

Scientific EffectWedge: Wedge

Implementation Method 3

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS12352378B2Expansion plug and system and method employing same

Publication Date: 2025.07.08 PLEWA ROBERT

AI summary

An expansion plug includes a first collar configured to advance as it rotates relative to a shaft, a second collar configured to move axially along the shaft without rotating, a first expanding structure, and a second expanding structure disposed in the stated order on the shaft. When the first collar is rotated in an advancement direction, opposite sides of the second expanding structure are moved closer together to expand the second expanding structure, and then opposite sides of the first expanding structure are moved closer together to expand the first expanding structure.