Divided Mechanical Seal Coupling Tool Design

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Solution Overview

Problem

Division type mechanical seals face challenges in achieving precise assembly and processing due to high precision requirements, leading to increased costs and difficulties in temporary assembly and disassembly, especially with brittle materials, and require complex surface finishing and high precision processing.

Innovation Solution

A division type mechanical seal design that uses a coupling tool with a deformable tube, which allows for flexible adjustment and buffering, reducing the need for precise processing and surface finishing, and enables stable temporary assembly and easy disassembly by utilizing friction and deformation, eliminating the need for precise abutment confirmation and reducing the risk of breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If projecting streaks and grooves are formed on divided faces for positioning, then radial positioning precision is improved, but axial positioning requires additional flange structures increasing device complexity

Engineering Contradiction:
Improvepositioning precision of divided facesVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines radial positioning (through projecting streaks and grooves) and axial positioning (through the same streak-groove interface) functions into a single integrated structure. The projecting streak on one divided face fits into the groove on the other divided face, simultaneously providing both radial alignment and axial positioning, thereby eliminating the need for separate flange structures.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If high precision processing is performed on divided faces and flange, then assembling precision is improved, but processing time increases

Engineering Contradiction:
Improveassembling precisionVSAvoidprocessing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs self-aligning and self-positioning features where the projecting streak automatically fits into the groove during assembly. This self-service mechanism ensures high assembling precision without requiring extensive precision machining or post-assembly adjustments, thereby reducing processing time while maintaining accuracy.

Inventive Principle:
Principle #25Self-service

3Strength

If metal taper pin is used for coupling divided sealing rings, then structural strength is improved, but confirmation of abutment and surface finishing are required increasing processing complexity

Engineering Contradiction:
Improvecoupling strengthVSAvoidprocessing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent introduces a tube as an intermediary coupling element between the divided sealing rings. This tube fits into holes formed through the divided rings and provides coupling strength while eliminating the need for metal taper pins. The tube-based coupling requires no abutment confirmation or surface finishing tasks, simplifying the processing while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If through hole is formed through divided sealing rings for coupling, then ease of assembly is improved, but precision requirement for hole formation increases processing time

Engineering Contradiction:
Improveease of assemblyVSAvoidhole positioning precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent incorporates positioning features (projecting streaks and grooves) that are formed during the initial manufacturing process. These pre-formed features automatically guide and position the through holes during assembly, ensuring high precision without requiring complex hole formation operations. The positioning features are created in advance, making the subsequent hole formation and assembly processes simpler and faster.

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

The solution ensures improved assembling precision, reduces processing time and costs, enhances workability, and allows for flexible adjustment and easy disassembly, while preventing deformation towards the inner diameter and efficiently expanding to the outer diameter, thereby maintaining the integrity of the seal.

Implementation Method 1

a tube (57) including a tubular body to be fitted to a shaft portion (55a) of the bolt (55)

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

A temporary assembling state of the divided sealing rings can be maintained by utilizing friction between an outer face of the tube and an inner face of the through hole portion due to deformation of the tube

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3070378B1Divided mechanical seal
Publication Date: 2019.04.10 EAGLE INDS
  • EP3070378B1 patent drawingFigure 1
  • EP3070378B1 patent drawingFigure 2
  • EP3070378B1 patent drawingFigure 3(a)~3(b)

AI summary

A division type mechanical seal with which assembling precision on divided contact faces are improved, workability at the time of temporary assembling is refined, and no excessive precision is required in mechanical processing at the time of manufacturing is provided. The mechanical seal includes a through hole portion 50 formed over two divided sealing rings so as to go over divided contact faces 12a, 13a of the two divided sealing rings 12, 13 adjacent to each other in the circumferential direction, and a coupling tool 54 inserted into the through hole portion 50 to couple the two adjacent divided sealing rings 12, 13. The coupling tool 54 includes a bolt 55, a nut 56, and a tube 57 fitted to a shaft portion 55a of the bolt, and the tube 57 is compressed in the axial direction and expanded in the outer diameter direction when the two adjacent divided sealing rings 12, 13 are coupled by fastening the nut 56.