Segment Heat-Shrink Sleeve for Durable Pipe Fitting Cladding

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Solution Overview

Problem

Existing methods for post-encapsulating tubular fittings, such as heat-shrink sleeves, fail to provide a mechanically resilient and durable solution for non-straight pipe sections like elbows and T-pieces, as they either compress or do not conform to standard geometric shapes required for underground piping.

Innovation Solution

Cutting expanded plastic pipe material into axial segment elements, rejoining them at specific angles to form a segment shrink sleeve, which is then butt-welded using a perforated heating mirror and shrunk onto the core pipe using heat, creating a durable and watertight outer layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional heat-shrink sleeves are used for post-encapsulation of non-straight pipe sections, then the process is simple, but the mechanical resilience and durability are insufficient

Engineering Contradiction:
Improvemechanical resilience and durabilityVSAvoidencapsulation process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shrink sleeve is divided into multiple axial segment elements that can be independently positioned and welded at specific angles. This segmentation allows the sleeve to conform to non-straight pipe sections like elbows and T-pieces while maintaining mechanical resilience and durability through proper angular alignment of segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segment elements are pre-cut from expanded plastic pipe material with predetermined angles before assembly. This preliminary preparation enables the segments to be quickly joined at correct angles without requiring complex positioning during the encapsulation process, balancing durability with process efficiency.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If standard heat-shrink sleeves are used for non-straight pipe sections, then installation is easy, but geometric shape standards are not met

Engineering Contradiction:
Improvegeometric shape conformityVSAvoidpost-encapsulation process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By dividing the shrink sleeve into angular segments, each element can be precisely cut and joined at specific angles to match standard geometric requirements for pipe fittings. This ensures elbows, T-pieces, and other non-straight sections meet geometric shape standards while maintaining ease of installation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different segment elements are cut at different angles according to the specific geometric requirements of the pipe fitting being encapsulated. This localized customization of segment angles ensures precise conformity to geometric standards for various fitting types without complicating the overall manufacturing process.

Inventive Principle:
Principle #3Local quality

3Reliability

If conventional adhesive tapes are used for post-encapsulation, then the process is simple, but watertightness and mechanical strength are insufficient

Engineering Contradiction:
Improvewatertightness and mechanical strengthVSAvoidencapsulation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention uses expanded plastic pipe material that undergoes thermal contraction when heated. This parameter change from expanded to contracted state creates a tight, watertight fit around the pipe fitting with high mechanical strength, eliminating the need for adhesives while maintaining encapsulation efficiency through a single heating step.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The shrink sleeve is made from expanded plastic pipe material that combines the properties of structural integrity (from the pipe material) with shrinkage capability (from the expanded structure). This composite material provides both watertightness and mechanical strength while maintaining a relatively simple encapsulation process.

Inventive Principle:
Principle #40Composite materials

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

This method allows for efficient post-encapsulation of complex pipe fittings like pipe bends and T-pieces, ensuring mechanical resilience and watertightness, conforming to geometric standards for underground piping.

Implementation Method 1

the segment shrink sleeve shrinks when heat is applied

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 2

These are materials, particularly deformed thermoplastics, that have shape memory and will return to their original shape when heat is applied

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Polymer

Data Source

PatentEP3530434B1Method for additional cladding of a pipe form part
Publication Date: 2023.03.29 EGEPLAST INT
  • EP3530434B1 patent drawingFigure 1
  • EP3530434B1 patent drawingFigure 2
  • EP3530434B1 patent drawingFigure 3

AI summary

For multi-layered pipe fittings, such as pipe bends, it is not possible to use conventional heat shrink tubing for post-coating, as a heat shrink tube would compress on the inside of the pipe bend of the fitting. The present invention relates to a method for post-coating pipe fittings in which the pipe fitting is encased by means of a heat shrink sleeve (12) that shrinks when heat is applied. According to the invention, a plastic pipe material expanded under pressure and heat is first cut into axial segment elements. These segment elements (12a, 12b, 12c, 12d) are then reassembled at angles corresponding to the pipe fitting to be produced to form a segment heat shrink sleeve (12). The segment elements are butt-welded together to form a segment heat shrink sleeve using a perforated heating mirror, and then the segment heat shrink sleeve is shrunk by applying heat.This provides a method for post-coating a pipe fitting that is more efficient than known methods and leads to mechanically resilient and durable pipe fittings.