Seal Extraction Tool Collet Wedge Mechanism

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Solution Overview

Problem

Conventional tools for extracting annular carbon face seals from equipment bores are skill-dependent, prone to damage during the 'walking out' extraction process, and can cause damage to both the seal and the pump casting due to the need for precise alignment and insertion into location pin bores.

Innovation Solution

A tool featuring a multi-legged collet that grips the seal using a wedge element, allowing for precise axial alignment and axial extraction force application, eliminating the need for insertion into location pin bores and preventing the 'walking out' extraction process, thereby reducing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional tool with legs is inserted into location pin bores to extract the seal, then the extraction process can be initiated, but the tool requires high operator skill for correct insertion and may fail to locate the seal face, resulting in damage to the seal and bore

Engineering Contradiction:
Improveoperator skill requirementVSAvoidextraction success rate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a collet as an intermediary gripping mechanism between the extraction tool and the seal. Instead of directly inserting legs into location pin bores, the collet engages with the seal's outer circumference, providing a more reliable and skill-independent method of seal engagement and extraction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the conventional tool uses a 'walking out' extraction process, then the seal can be removed from the bore, but the process can result in damaged seals and potential scouring damage to the pump casting

Engineering Contradiction:
Improveextraction capabilityVSAvoiddamage to seal and bore
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional extraction approach by using a collet that grips the seal's outer circumference and applies axial extraction force directly, rather than using legs that walk along the location pin bores. This reversed methodology eliminates the walking out process and its associated damage risks.

Inventive Principle:
Principle #13The other way round (Inversion)

3Manufacturing precision

If precise alignment of tool legs with location pin bores is required, then the extraction tool can engage the seal, but the alignment difficulty increases and insertion becomes more challenging

Engineering Contradiction:
Improvetool alignment precisionVSAvoidtool insertion ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent extracts the requirement for precise alignment with location pin bores by removing the legs entirely and replacing them with a collet. The collet's circumferential gripping action eliminates the need for precise borescope alignment, significantly easing the insertion process while maintaining extraction effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The tool enables safe and precise extraction of annular carbon face seals by gripping the seal with a collet, reducing the risk of damage to both the seal and the bore, and ensuring easy alignment, thus improving the extraction process.

Implementation Method 1

A first actuator is provided to pull the wedge element into the collet, thereby expanding the collet and causing it to grip an inner surface of the seal

Methodology Applied
Scientific EffectWedge: Wedge

Data Source

PatentEP3045269B1Seal extraction tool
Publication Date: 2021.05.19 ROLLS ROYCE PLC
  • EP3045269B1 patent drawingFigure 1
  • EP3045269B1 patent drawingFigure 2
  • EP3045269B1 patent drawingFigure 3~4

AI summary

A tool is provided for extracting an annular carbon face seal from a bore of equipment in which the seal is installed. The tool has an extraction tube (2) for insertion into the bore at an entrance thereof such that, when the extraction tube (2) is fully inserted into the bore, a multilegged collet (3) formed at a distal end of the extraction tube (2) is located within the seal and a proximal end of the extraction tube is accessible (2) at the entrance of the bore. The tool further has an elongate member which extends along the central passage of the extraction tube (2). A wedge element (5) provided at a distal end of the elongate member is located at a mouth of the collet (3). A proximal end of the elongate member is accessible at the proximal end of the extraction tube (2). The tool further has a support arrangement for reacting an axial extraction force applied to the extraction tube (2) to the equipment. The tool further has a first actuator (6) located at the proximal end of the elongate member. The tool is configured such that actuation of the first actuator (6) causes the wedge element (5) to be pulled into collet (3), thereby expanding the collet (3) and causing it to grip an inner surface of the seal. The tool further has a actuation second actuator (8) which operatively connects the extraction tube (2) and the support arrangement such that actuation of the second actuator causes the axial extraction force to be applied to the extraction tube (2), whereby the extraction force, reacted to the equipment, extracts the seal from the bore when the seal is gripped by the collet (3).