Steam Turbine Valve Linkage Layout for Stable Rod Motion

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Solution Overview

Problem

Existing valve devices for steam turbines face challenges in securing stable rod movement while maintaining assembling properties, often resulting in increased size and complexity due to orthogonal connections and potential clogging from steam flow, which complicates the incorporation of valve components and can lead to assembly issues.

Innovation Solution

A valve device configuration featuring a valve casing with orthogonal intermediate and outlet flow paths, a linkage shaft, and an actuator unit with a hydraulic cylinder and linking unit that converts piston rod motion into linear motion of the intermediate rod, ensuring stable movement and improved assembling properties by simplifying the internal space and reducing size, and using a rod guide with control oil to enhance slidability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the main steam stop valve rod is moved in the horizontal direction with a hydraulic cylinder protruding at the outer side, then the rod can be moved smoothly, but the valve device becomes large in the horizontal direction

Engineering Contradiction:
Improverod movement smoothnessVSAvoidvalve device horizontal size
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent changes the movement direction of the main steam stop valve rod from horizontal to vertical direction, and repositions the hydraulic cylinder from protruding outward to being integrated within the valve rod structure. This dimensional reorientation allows the actuator to be housed inside the valve rod, significantly reducing the horizontal footprint of the valve device while maintaining smooth rod movement capability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the main steam stop valve rod is moved in the vertical direction parallel to the steam-regulating valve rod, then the horizontal size is reduced, but the flow path shapes become complicated and assembling property deteriorates

Engineering Contradiction:
Improvevalve device horizontal sizeVSAvoidassembling property
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent divides the valve device into separate modular components: the steam-regulating valve assembly and the main steam stop valve assembly are positioned orthogonally and can be assembled independently. The flow paths are designed as separate channels that intersect at right angles, allowing each valve component to be manufactured and tested separately before final integration, thereby maintaining good assembling property despite the compact vertical arrangement

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If a guide with very narrow clearance is provided to move the rod only in the horizontal direction, then the rod movement is controlled, but scale adheres to the rod and clogs the narrow clearance region

Engineering Contradiction:
Improverod movement controlVSAvoidrod movement stability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the rod movement direction from horizontal to vertical, and provides guides that extend along the vertical movement direction. This orientation change prevents scale accumulation on the rod surface, as the vertical movement allows condensate and scale to drain downward rather than accumulating in horizontal clearance gaps, thereby maintaining reliable rod movement control without clogging

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration ensures stable and accurate movement of the intermediate rod, reduces the size of the valve device, and improves assembling properties by simplifying internal structures and preventing clogging, thus enhancing the overall performance and efficiency of the steam turbine.

Implementation Method 1

a hydraulic cylinder that is configured to cause a piston rod portion to advance and retreat in a direction orthogonal to the second center axis direction

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

a rod guide portion that has a tubular shape into which the piston rod portion is inserted and guides movement of the piston rod portion

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3699402B1Valve device and steam turbine
Publication Date: 2023.03.29 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP3699402B1 patent drawingFigure 1
  • EP3699402B1 patent drawingFigure 2
  • EP3699402B1 patent drawingFigure 3

AI summary

A valve device includes a valve casing 21, an intermediate rod portion 29, and an intermediate actuator unit 30. In the valve casing 21, a rod insertion hole into which the intermediate rod portion 29 can be inserted is formed. The intermediate actuator unit 30 includes a hydraulic cylinder that causes a piston rod portion to advance and retreat in a direction orthogonal to a second center axis direction D2. The hydraulic cylinder includes a rod guide portion that guides movement of the piston rod portion. A gap between an inner circumferential surface of the rod insertion hole and an outer circumferential surface of the intermediate rod portion 29 is formed to be wider than a gap between an inner circumferential surface of the rod guide portion and an outer circumferential surface of the piston rod portion.