CSST Jacket-Stripping Blade Layout for Flashover Resistance

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Solution Overview

Problem

Corrugated stainless steel tubing (CSST) is vulnerable to failure due to physical or electrical forces like lightning or fault currents, leading to potential flashovers and damage, especially when installed in close proximity to other conductive systems, which can result in the escape of fuel gas.

Innovation Solution

A jacket-stripping tool designed specifically for CSST, featuring angled cutting blades and internal annular ribs, allows for precise removal of outer jacket layers without cutting through intermediate conductive layers, thereby reducing the risk of flashovers and enhancing the tubing's resistance to electrical discharges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the dielectric jacket surrounds CSST to provide insulation, then electrical protection is improved, but the jacket breaks down under flashover conditions creating pinholes that focus heat and reduce puncture resistance

Engineering Contradiction:
Improveelectrical protectionVSAvoidpuncture resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the dielectric jacket from specific locations on the CSST, particularly at corrugation valleys, to prevent the jacket from breaking down and creating pinholes during flashover events. This extraction eliminates the harmful effect of the jacket while preserving its beneficial electrical insulation properties in other areas.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different treatments to different locations on the CSST - the dielectric jacket is removed at corrugation valleys where flashover vulnerability is highest, while maintaining the jacket in other areas where electrical protection is needed. This local differentiation optimizes both electrical protection and flashover resistance.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If cutting blades are positioned to remove jacket layers, then jacket removal precision is improved, but the risk of cutting through intermediate conductive layers increases

Engineering Contradiction:
Improvejacket removal precisionVSAvoidflashover risk
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The cutting blades are positioned to remove jacket material selectively from specific locations (corrugation valleys) rather than uniformly across the entire CSST. This localized approach allows precise jacket removal where needed while preserving the jacket and conductive layers in other critical areas, preventing flashover pathways.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tool is designed to pre-position cutting blades at precise locations before contact with the CSST, ensuring that jacket removal occurs only at predetermined safe locations. This preliminary positioning prevents accidental cutting of intermediate conductive layers during the jacket removal process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3010687B1Jacket-stripping tools, kits, methods of removing one or more external jacket layers, and blades
Publication Date: 2021.12.08 TITEFLEX
  • EP3010687B1 patent drawingFigure 1A~1B
  • EP3010687B1 patent drawingFigure 2A~2D
  • EP3010687B1 patent drawingFigure 3A

AI summary

One aspect of the invention provides a jacket- stripping tool including: a reference stop adapted and configured to contact an end of corrugated stainless steel tubing; and one or more cutting blades arranged substantially perpendicular to a central axis of the tool and adapted and configured to create one or more cuts through one or more external jacket layers of the corrugated stainless steel tubing. At least one of the one or more cutting blades is positioned relative to the reference stop such that the at least one of the one or more cutting blades is a multiple of a distance between adjacent corrugation valleys of the corrugated stainless steel tubing.