Air Gap Baffle Train Alignment for Turbine Generators

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Solution Overview

Problem

Turbine generators experience axial and radial misalignments of air baffle sectors due to dimensional inconsistencies in cotton reinforced phenolic resin materials, leading to loosening of baffle trains and compromised cooling airflow zones within the air gap between the stator and rotor.

Innovation Solution

The baffle train apparatus features linearly aligned baffle blocks with axial spacer rods and locking engagement members to maintain precise axial and radial alignment, utilizing biasing elements like arch springs or coil springs to accommodate dimensional instability and ensure consistent airflow zone formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cotton reinforced phenolic resin material is used for baffle wedges and spacers, then ease of manufacture is improved, but dimensional consistency deteriorates due to water absorption, shrinkage and thermo-mechanical creep

Engineering Contradiction:
Improveease of manufactureVSAvoiddimensional consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The baffle train is divided into modular components (baffle blocks, axial spacer rods, locking engagement members) that can be independently manufactured and assembled. This segmentation allows each component to be optimized for dimensional stability while maintaining ease of manufacture through standardized parts.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from cotton reinforced phenolic resin to materials with superior dimensional stability, such as metal baffle blocks with composite or ceramic coatings. This material substitution maintains manufacturability while dramatically improving dimensional consistency and resistance to shrinkage and creep.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If baffle wedge cable tensioning is used to restrain wedges, then radial position is maintained, but axial alignment deteriorates due to impact on ultimate linear location of baffle sectors

Engineering Contradiction:
Improveradial positionVSAvoidaxial alignment
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The alignment function is separated into two independent systems: radial positioning via cable tensioning and axial positioning via spacer rods with locking members. This segmentation eliminates the coupling between radial and axial alignment, allowing each to be optimized independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Axial spacer rods serve as intermediary elements that provide precise axial positioning of baffle blocks independent of the cable tensioning system. The locking engagement members then secure this axial position, acting as intermediaries that transfer and maintain the aligned position without requiring cable tension adjustment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If extensive wedge trimming is performed to align baffle sectors, then manufacturing precision is improved, but productivity deteriorates due to requiring multiple attempts

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Axial spacer rods are pre-manufactured with precise lengths that encode the desired axial positions of multiple baffle blocks. This preliminary action of pre-calculating and pre-manufacturing spacer rods with built-in alignment information eliminates the need for iterative trimming and multiple adjustment attempts during assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spacer rod assembly system is designed to be self-aligning through precision-machined mating surfaces and interference fits. Once the spacer rod is inserted, the baffle blocks automatically assume their correct axial positions without requiring operator intervention for trimming or adjustment, making the system self-servicing during assembly.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If baffle trains are allowed to operate without rigid constraints, then adaptability to dimensional changes is improved, but reliability deteriorates due to loosening and misalignment over time

Engineering Contradiction:
Improveaccommodation of dimensional changesVSAvoidalignment stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system employs dynamic elements including spring-loaded cable tensioners that automatically adjust to material shrinkage and thermal expansion, and locking engagement members that maintain rigid constraints while allowing for controlled adjustment. This dynamic design maintains reliability by adapting to dimensional changes without losing alignment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cable tensioning system allows for parameter changes in tension force to compensate for material dimensional changes over time. The spring-loaded mechanism automatically adjusts the tension parameter to maintain optimal radial positioning even as materials undergo shrinkage or expansion during operation.

Inventive Principle:
Principle #35Parameter changes

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 solution maintains the axial and radial position of baffle sectors, preventing misalignment and ensuring stable cooling airflow zones within the generator, even with potential dimensional changes, thereby enhancing operational efficiency and reducing the need for extensive initial alignment.

Implementation Method 1

The biasing element radially biases the upper surface of its corresponding baffle block against toward the stator bore and can flex to accommodate baffle block thickness dimensional instability

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3130066B1Air gap baffle train for turbine generator
Publication Date: 2021.03.03 SIEMENS ENERGY INC
  • EP3130066B1 patent drawingFigure 1
  • EP3130066B1 patent drawingFigure 2
  • EP3130066B1 patent drawingFigure 3~4

AI summary

A baffle train for turbine generator air baffles independently aligns axial position of the composite air baffle along a stator core bore axial slot. Air baffle sectors that form the composite air baffle are coupled to baffle blocks of the baffle train. The baffle blocks are positioned axially along at least one axial spacer rod corresponding to the desired position of the composite air baffle within the stator bore. The baffle blocks are locked into position by a locking engagement member. Wedge blocks are axially spaced on a reciprocating wedge block rod within the stator slot below the baffle blocks. A biasing element, such as arched leaf spring, tensions the baffle block radially inwardly toward the stator bore when the wedge blocks are reciprocated below the baffle blocks.