Grid Shutter Friction Reduction via Steam Pressure Lifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Steam turbines with controlled extraction face challenges in reducing friction and wear forces within grid shutters due to differential pressures, leading to increased maintenance needs and limitations in operating parameters.
Innovation Solution
A steam turbine with a grid shutter system featuring a fixed grid and a movable grid, where the fixed grid has a groove supplied with high-pressure steam to reduce friction forces, and a solenoid valve and non-return valve control the steam supply to adjust pressure and minimize wear, without external intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a grid shutter with two movable parts is used to control extraction pressure, then the turbine casting becomes simpler and lighter, but friction forces and wear between the grid parts increase due to differential pressure
Solution Approach 1:
A steam supply groove is introduced as an intermediary element between the fixed and movable grids. High-pressure steam supplied to this groove creates a pressure difference that generates a lifting force on the movable grid, mediating the interaction between the two grids to reduce friction and wear while maintaining the simple casting structure
Solution Approach 2:
The invention uses pneumatic pressure from high-pressure steam to reduce friction forces. The steam supply groove utilizes fluid pressure to create a lifting effect on the movable grid, reducing contact friction between grid parts without compromising the simple casting design
2Reliability
If special coatings or rolling systems are developed to reduce friction forces, then friction and wear are reduced, but maximum operating temperature and pressure are limited and maintenance is still required
Solution Approach 1:
Instead of relying on special coatings with temperature and pressure limitations, the invention uses pneumatic pressure from high-pressure steam to reduce friction. This approach can handle higher operating temperatures and pressures since it uses the steam environment itself rather than temperature-sensitive coatings
Solution Approach 2:
The system uses the turbine's own high-pressure steam to reduce friction and wear, making the system self-servicing. The steam that would otherwise be wasted is utilized to protect the grid shutter components, eliminating the need for external cooling systems or specialized temperature-resistant materials
3Reliability
If the movable grid is positioned to compensate for friction forces, then friction wear is reduced, but the forces required to change angular position of the shutter increase
Solution Approach 1:
High-pressure steam supplied to the groove creates a pneumatic lifting force that counteracts friction forces. This reduces the mechanical force required to move the movable grid angularly, as the steam pressure assists the motion rather than resisting it through friction
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 reduces friction forces and wear on the grid components, minimizing maintenance requirements and maintaining operational flexibility by using internal steam sources to adjust the shutter's operation, thus enhancing the turbine's efficiency and reliability.
Implementation Method 1
one of the gates of the shutter comprises at least one groove facing the other gate and supplied with high pressure steam
Implementation Method 2
The vapor pressure prevailing in this groove 26 causes a force tending to separate the movable and fixed grids and, consequently, to reduce the friction forces
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The device has a grid shutter (20) arranged in a steam flow path, and including a grid (25) movable with respect to a fixed grid (24) for delimiting an adjustable passage section for the shutter. An application unit applies an effort between the fixed and movable grids, and has an annular groove (26) formed in the fixed grid. The groove is supplied with steam collected in an expansion stage that is located near a steam intake.