Split Mechanical Seal with Selective Axial Biasing for Self-Alignment

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Solution Overview

Problem

Conventional split mechanical seals face difficulties in aligning rotary and stationary seal ring segments during installation, leading to potential misalignment and premature contact, which can result in seal face damage and reduced seal life due to the need for manual force to overcome biasing mechanisms and the smooth, flat nature of axial seal ring faces.

Innovation Solution

The mechanical seal assembly features non-flat, axially extending seal ring faces that interlock for self-alignment and a movable spring engaging mechanism that selectively removes axial biasing force during installation, allowing easier alignment and reducing the risk of seal ring damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional biasing mechanisms (clips or springs) are used to maintain sealing contact, then sealing effectiveness is improved, but installation difficulty increases due to the need to manually overcome the biasing force during assembly

Engineering Contradiction:
Improvesealing effectivenessVSAvoidinstallation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The biasing mechanism is designed to automatically engage with the seal ring after installation, eliminating the need for manual force application during assembly. The spring or clip is pre-positioned to engage with the seal ring's biasing surface, so that normal sealing contact is achieved automatically without requiring the installer to overcome the biasing force.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A biasing surface is provided on the seal ring that acts as an intermediary between the biasing mechanism and the seal ring. This biasing surface allows the biasing force to be applied at a specific location, enabling automatic engagement and simplifying installation by eliminating the need to manually overcome the biasing force during assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If smooth, flat axial seal ring faces are used, then manufacturing simplicity is improved, but alignment precision deteriorates during installation leading to misalignment and potential seal face damage

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidalignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Instead of using completely flat axial seal ring faces, the invention introduces a curved or inclined biasing surface on the axial face of the seal ring. This curved surface works in conjunction with the biasing mechanism to provide self-aligning features during installation, improving alignment precision while maintaining manufacturing simplicity. The curvature allows the seal ring to automatically align during the engagement process.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of operation

If force is applied to overcome biasing mechanisms during installation, then seal ring segments can be assembled, but seal face damage risk increases due to premature contact and manual force requirements

Engineering Contradiction:
Improveassembly capabilityVSAvoidseal face damage risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The biasing mechanism is designed to engage automatically after the seal ring segments are positioned, eliminating the need to apply force to overcome the biasing mechanism during installation. The spring or clip is pre-positioned to engage with the biasing surface on the seal ring, allowing segments to be assembled without premature contact that could cause damage.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If seal ring segments are assembled with biasing force already engaged, then sealing contact is achieved, but alignment difficulty increases requiring multiple attempts and increasing installation time

Engineering Contradiction:
Improvesealing contactVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The seal ring is designed with self-aligning features through the biasing surface and biasing mechanism combination. During installation, the seal ring automatically aligns itself as the biasing mechanism engages, eliminating the need for the installer to manually adjust or realign segments. This self-aligning capability ensures proper sealing contact is achieved in a single attempt, reducing installation time and preventing damage from multiple alignment attempts.

Inventive Principle:
Principle #25Self-service

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 enables easier and more precise alignment of seal ring segments, reduces the force required for installation, and minimizes the risk of seal face damage, resulting in improved installation efficiency and extended seal life by ensuring proper seating and contact.

Implementation Method 1

a spring positioned within the gland assembly and engaging the stationary seal ring to apply an axial biasing force to the stationary seal ring

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the movable member moves within the groove from the engaged position into the disengaged position such that the axial biasing force is removed from or applied to the stationary seal ring

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3514415B1Self aligning split mechanical seal employing a selectively engageable axial biasing assembly
Publication Date: 2021.05.26 CHESTERTON AW CO
  • EP3514415B1 patent drawingFigure 1
  • EP3514415B1 patent drawingFigure 2
  • EP3514415B1 patent drawingFigure 3

AI summary

A split mechanical seal for mounting to a housing containing a rotating shaft comprising a gland assembly configured for mounting to the housing and forming a chamber, where the gland assembly includes a top surface having a gland groove formed thereon. The gland groove is formed at least in part by at least one raised wall portion that extends axially outwardly from the top surface. The seal also includes a stationary seal ring having a groove or recess formed in an inner surface.