Steam Turbine Valve Seat Sealing With Strainer-Pressed Elastic Support

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Solution Overview

Problem

Existing valve devices in steam turbines face challenges in maintaining sealing properties between the intermediate valve seat portion and the valve casing while ensuring maintainability, as fixing the valve seat portion improves sealing but reduces workability, and making it detachable leads to fluid leaks.

Innovation Solution

A valve device design featuring a detachable intermediate valve seat portion with an energizing member that is elastically deformable, pressed by a strainer, enhancing the sealing property between the valve seat and the casing without compromising workability during maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the intermediate valve seat portion is fixed to the valve casing by welding, then the sealing property is improved, but the workability at the time of disassembly and assembly during maintenance deteriorates

Engineering Contradiction:
Improvesealing propertyVSAvoidworkability during maintenance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The valve seat portion is divided into a detachable intermediate valve seat portion and a fixed valve casing, allowing the intermediate portion to be removed for maintenance while the casing remains in place. This segmentation enables maintenance access without complete disassembly while maintaining sealing through the detachable design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate valve seat portion is designed to be dynamically detachable rather than permanently fixed, allowing it to be removed when maintenance is needed and reinstalled when complete. This dynamic configuration balances the need for sealing with the need for maintenance access.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the intermediate valve seat portion is made detachable from the valve casing, then the workability at the time of disassembly and assembly is improved, but a gap is formed between the intermediate valve seat portion and the valve casing resulting in fluid leakage

Engineering Contradiction:
Improveworkability during maintenanceVSAvoidsealing property
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

An energizing member is pre-installed between the intermediate valve seat portion and the valve casing to continuously apply pressing force. This preliminary action ensures that the sealing interface remains under constant pressure to prevent fluid leakage while allowing the valve seat portion to be detachable for maintenance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The energizing member acts as an intermediary element between the intermediate valve seat portion and the valve casing, providing the necessary sealing force without requiring permanent fixation. This mediator enables both detachability for maintenance and reliable sealing during operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If welding is used to fix the intermediate valve seat portion to the valve casing, then the sealing property is secured, but the complexity of manufacturing and assembly increases

Engineering Contradiction:
Improvesealing propertyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The welding process is replaced with a mechanical pressing system using the energizing member. Instead of permanently joining components through welding, the system uses elastic deformation and continuous pressing force to achieve sealing, simplifying manufacturing and enabling disassembly without specialized welding equipment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The sealing mechanism changes from permanent thermal joining (welding) to reversible mechanical pressing. By changing the sealing parameter from weld strength to pressing force, the system achieves comparable sealing reliability while dramatically reducing manufacturing complexity and enabling maintenance.

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

The solution effectively improves the sealing property between the intermediate valve seat and the valve casing, allowing for both secure sealing and easy maintenance by using an energizing member to press the valve seat against the casing, even when detachable, thus preventing fluid leaks.

Implementation Method 1

at least one energizing member that is disposed between the strainer and the intermediate valve seat portion, is elastically deformable in the direction connecting the lid portion and the intermediate valve seat portion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4015782A1Valve device for a steam turbine
Publication Date: 2022.06.22 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP4015782A1 patent drawingFigure 1
  • EP4015782A1 patent drawingFigure 2
  • EP4015782A1 patent drawingFigure 3

AI summary

A valve device (2) includes a valve casing (21) that includes a valve casing main body (211), in which an inlet flow path (51), an intermediate flow path (52), and an outlet flow (53) path are formed, and a lid portion (212) that closes an external opening portion (54) formed in the valve casing main body, an intermediate valve seat portion (27) that is detachable from the valve casing main body, a strainer (60) that extends in a direction connecting the lid portion and the intermediate valve seat portion and is disposed between the lid portion and the intermediate valve seat portion, and an energizing member (70) that is disposed between the strainer and the intermediate valve seat portion and is energized to improve the sealing property between the intermediate valve seat portion and the valve casing main body. The strainer is disposed with the energizing member pressed toward the valve casing main body (211).