Steam Generator Tube Internal Fins via Insert Extraction

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Solution Overview

Problem

Current methods for manufacturing steam generator tubes are limited in material flexibility and efficiency, particularly when using higher chromium alloys for high steam parameters, as they require complex integrated processes and are costly.

Innovation Solution

A method involving a template shaft with grooves is used to introduce twist-generating built-in bodies into smooth tubes, allowing for independent material selection and simple production of internally finned tubes, enabling the use of higher chromium alloys and reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cold-drawing process is used to produce internally finned tubes, then manufacturing simplicity is improved, but material flexibility deteriorates (limited to maximum 5% chromium)

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmaterial flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention divides the tube into two separate components: a smooth tube and an insert body with internal fins. The insert body is manufactured separately using cold-drawing process and then inserted into the smooth tube. This segmentation allows the smooth tube to be made from high-chromium alloys (greater than 5% chromium) while the insert body can be made from materials suitable for cold-drawing, thus resolving the contradiction between manufacturing simplicity and material flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The internal fin structure is extracted from the integrated tube manufacturing process and becomes a separate insert body. This insert body is produced independently using cold-drawing process and then inserted into the smooth tube. By taking out the fin structure as a separate component, the invention enables the use of high-chromium alloys for the tube while maintaining the manufacturing advantages of cold-drawing for the insert.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If integrated production process is used for internally finned tubes with high chromium alloys, then material flexibility is improved, but device complexity deteriorates

Engineering Contradiction:
Improvematerial flexibilityVSAvoidprocess complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention segments the production process into two independent stages: manufacturing the smooth tube with high-chromium alloy and separately manufacturing the insert body with internal fins. The insert body is then inserted into the smooth tube. This segmentation simplifies the overall process by allowing each component to be optimized independently, avoiding the complexity of integrated high-chromium alloy finned tube production.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The internal fin structure is extracted as a separate insert body that can be manufactured using simple cold-drawing process. This insert is then inserted into the high-chromium alloy smooth tube. By extracting the fin structure from the integrated production process, the invention reduces device complexity while maintaining material flexibility for high-chromium alloys.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If auxiliary fixing devices are used to secure the insert body, then reliability is improved, but device complexity deteriorates

Engineering Contradiction:
Improvefixing reliabilityVSAvoidauxiliary device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insert body is designed with a geometry that enables self-fixing within the smooth tube. The cold-drawing process creates an insert body that, when inserted, automatically secures itself through friction and geometric interlocking without requiring additional auxiliary fixing devices. This self-service mechanism maintains reliability while eliminating the complexity of auxiliary fixing systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention removes the need for auxiliary fixing devices by extracting the securing function and integrating it into the insert body design itself. The insert body's geometry and surface properties, resulting from the cold-drawing process, provide inherent fixation capability, thus eliminating auxiliary devices while maintaining reliable fixing.

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

This method enables the production of internally finned steam generator tubes with high chromium alloys suitable for high steam parameters, offering increased efficiency and cost-effectiveness, eliminating the need for complex integrated manufacturing processes and auxiliary devices.

Implementation Method 1

the installation body is fixed to the template shaft with a preload and the installation body lifts out of the grooves of the template shaft after releasing the fixing to the template shaft and is thus fixed in the steam generator tube independently

Methodology Applied
Scientific EffectPreload:

Data Source

PatentEP2577160B1Method for producing steam generator tubes
Publication Date: 2020.07.15 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP2577160B1 patent drawingFigure 1~3
  • EP2577160B1 patent drawingFigure 4

AI summary

A method for producing steam generator tubes is intended to allow a technically particularly simple production process and at the same time allow particularly high flexibility with regard to the materials that can be used to achieve a particularly high efficiency of a steam generator. For this purpose, an insert is fixed in slots (4) of a former shaft (1), the former shaft (1) with the insert is introduced into a steam generator tube, the fixing of the insert on the former shaft (1) is released and the former shaft (1) is removed again from the steam generator tube.