Closure Load Plug Assembly for Sealing Post-Tension Duct Ends

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Solution Overview

Problem

In post-tensioned concrete construction, existing methods for connecting segments of ducts face challenges with incomplete grouting and leakage due to difficulties in sealing the ends of duct segments, leading to potential air and water intrusion, especially when segments do not correspond with standard lengths.

Innovation Solution

A closure assembly is introduced, comprising a duct coupler assembly with a closure load plug and end cap, which includes a duct coupler assembly that fits against the duct segment, utilizing a duct receiving end with a cylindrical portion and conjunction portion for attachment, along with a gasket to prevent liquid intrusion, and a closure load plug with male threads that screws into a female coupler with threads, forming a seal with the end cap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epoxy is applied to seal duct segment ends, then sealing is achieved, but epoxy leaks out into the interface area and grout cannot flow fully through the duct assembly

Engineering Contradiction:
Improvesealing effectivenessVSAvoidgrout flow completeness
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The closure load plug is installed at the duct end before grouting to pre-prevent epoxy leakage. This preliminary sealing action ensures that when grout is pumped later, it flows completely through the duct without being blocked by leaked epoxy at the segment interface.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts the sealing function from the epoxy application process and assigns it to a dedicated closure load plug component. This separation allows the epoxy to serve its primary bonding function while the closure plug handles the sealing function, preventing epoxy from interfering with grout flow.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If duct segments are joined end-to-end with epoxy sealing, then connection is achieved, but air and water can intrude into the duct interior

Engineering Contradiction:
Improvesegment connectionVSAvoidair and water intrusion
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The closure load plug acts as an intermediary component between the duct end and the external environment. It provides a reliable seal that prevents air and water intrusion while allowing the duct segments to be connected end-to-end for ease of assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The closure load plug incorporates a closure gasket that forms a flexible seal at the duct end. This gasket prevents air and water intrusion while accommodating minor variations in duct end alignment during assembly.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If standard length duct segments are used, then manufacturing is simplified, but they may not correspond with the length of concrete pours

Engineering Contradiction:
Improveduct segment productionVSAvoidconcrete pour length compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The duct system is segmented into standardized modules that can be connected end-to-end using the closure load plug assembly. This segmentation allows flexible configuration to match various concrete pour lengths while maintaining simplified manufacturing of individual standard-length segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The closure load plug assembly serves as a universal connector that works with duct segments of any standard length. This multi-functional component enables both simplified manufacturing of standard segments and adaptability to different concrete pour lengths by simply varying the number of segments used.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3896237B1Closure load plug
Publication Date: 2024.07.03 SORKIN FELIX L
  • EP3896237B1 patent drawingFigure 1~2
  • EP3896237B1 patent drawingFigure 3
  • EP3896237B1 patent drawingFigure 4

AI summary

A closure assembly includes a section of duct, a duct coupler assembly, a closure load plug, and an end cap. The duct coupler assembly is fit against the section of duct. The closure load plug is mechanically connected to the duct coupler assembly. The end cap is mechanically connected to the closure load plug.