Sealing Ring Refurbishment Using One-Sided Laser Material Deposition

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Solution Overview

Problem

Current methods for manufacturing and maintaining sealing rings in steam turbines result in long delivery times, unnecessary procurement of oversized rings, high transportation costs, and excessive manufacturing expenses, as well as the disposal of old rings, which are not efficiently refurbished during maintenance.

Innovation Solution

A repaired sealing ring with opposite contact surfaces is refurbished by selectively applying material to one contact surface using methods like selective laser melting or laser metal deposition, allowing for in-situ restoration of the sealing function without needing new rings, and incorporating an insert ring in a groove for additional thickening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If forged parts are used for sealing rings, then reliability and sealing performance are improved, but procurement time and manufacturing costs increase significantly

Engineering Contradiction:

Improvesealing performanceVSAvoidprocurement time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies the discarding and recovering principle by refurbishing used sealing rings instead of discarding them. The process involves removing material from contact surfaces that have worn during service, then restoring the original dimensions and sealing performance through controlled material removal and subsequent heat treatment. This allows the rings to be reused multiple times, eliminating the need for long procurement cycles associated with manufacturing new forged parts.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent implements self-service by enabling the sealing rings to be refurbished in-situ at the customer's location rather than requiring return to the manufacturer. The refurbishment process includes portable machining capabilities and heat treatment equipment that can be deployed on-site, allowing the rings to service themselves through localized repair without interrupting plant operations or requiring lengthy shipping and manufacturing cycles.

Inventive Principle:

Principle #25Self-service

2Reliability

If sealing rings are procured with oversize to accommodate wear, then availability during maintenance intervals is improved, but transportation costs and handling complexity increase

Engineering Contradiction:

ImproveavailabilityVSAvoidtransportation costs

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the dimensions of sealing rings through controlled material removal during refurbishment. Instead of procuring oversized rings that require special handling and transportation, the rings are machined to precise dimensions on-site based on actual wear measurements. This eliminates the need for oversized inventory and reduces transportation requirements to standard sizes only.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If material is removed from contact surfaces during maintenance, then sealing performance is restored, but the ring thickness is reduced and the ring must be replaced

Engineering Contradiction:

Improvesealing performanceVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies preliminary action by performing controlled material removal from contact surfaces during scheduled maintenance intervals before the rings are completely worn. The process includes precise machining of the contact surfaces to restore original dimensions, followed by heat treatment to rejuvenate the material properties. This preliminary restoration extends the service life of the rings significantly, allowing multiple refurbishment cycles before replacement is necessary.

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

This approach reduces procurement and manufacturing costs, minimizes waste, and allows for on-demand refurbishment of sealing rings, thereby optimizing maintenance efficiency and reducing transportation expenses.

Implementation Method 1

material was applied in the form of a thickening (10) on only one contact surface (7) by means of selective laser melting or laser metal deposition

Methodology Applied

Scientific EffectSelective Laser Melting: Selective Laser Sintering

Implementation Method 2

material was applied in the form of a thickening (10) on only one contact surface (7) by means of selective laser melting or laser metal deposition

Methodology Applied

Scientific EffectLaser Metal Deposition: Laser

Data Source

PatentUS11286777B2Repaired ring and method for repairing a ring which is used for sealing purposes

Publication Date: 2022.03.29 SIEMENS ENERGY GLOBAL GMBH & CO KG

AI summary

By applying material on only one side in the case of a revision, seal rings can be easily rebuilt and reused.