Steam Valve Curvature Radius and Tapered Portion Design
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Solution Overview
Problem
Steam valves in power plants face issues with high-pressure steam turbulence causing noise, vibration, and erosion, and struggle to rapidly cut off steam supply due to limited flow passage area and high pressure loss, leading to potential damage and increased costs.
Innovation Solution
A steam valve design with a valve head portion having a curvature radius greater than 0.6 times the seat diameter, combined with a tapered portion tilted more than the valve head portion, to increase the flow passage area and guide steam flow effectively, reducing pressure loss and vibration while enabling rapid steam cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the curvature radius of the valve head portion is increased to reduce vibration, then the flow passage area increases and pressure loss decreases, but the valve body size increases leading to installation restrictions and cost rise
Solution Approach 1:
The patent applies local quality by differentiating the curvature radius of the valve head portion from the seat diameter with a specific ratio relationship (r>0.6D0), creating an optimized local geometry at the critical seating area that reduces vibration without requiring a proportionally larger overall valve body
Solution Approach 2:
The patent introduces a tapered portion on the upstream side of the valve head with a surface tilted at a specific angle, adding a dimensional element that guides steam flow effectively, reduces pressure loss, and minimizes vibration without increasing the valve body's overall volume
2Quantity of substance
If the lift amount of the valve body is increased to ensure enough steam supply, then the flow passage area increases, but it takes longer to change from full-open to full-closed position
Solution Approach 1:
The patent changes the geometric parameters of the valve head portion by setting the curvature radius ratio r>0.6D0 and adding the tapered portion with specific tilt angle, which optimizes the flow characteristics to provide sufficient steam supply with a smaller lift amount, thereby enabling faster cutoff response
3Object-affected harmful factors
If the curvature radius of the valve seat is increased to make the flow line vertical and reduce vibration, then the steam flow becomes steady, but the flow passage area between valve seat and valve body decreases causing large pressure loss
Solution Approach 1:
The patent applies local quality by setting the curvature radius of the valve head portion to satisfy r>0.6D0, creating an optimized local geometry that balances flow direction control with adequate flow passage area, avoiding the need for a larger valve seat curvature that would reduce the flow passage area
Solution Approach 2:
The patent adds a tapered portion with a surface tilted at a specific angle relative to the direction of relative movement, which guides steam flow effectively in the vertical direction while maintaining adequate flow passage area, thus reducing vibration without causing large pressure loss
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 design achieves a larger flow passage area with reduced pressure loss, allowing for immediate steam cutoff and minimized vibration, enhancing the safety and efficiency of steam turbine operations.
Implementation Method 1
a tapered portion arranged on an upstream side of the valve head portion, and whose surface is tilted toward a direction of relative movement of the valve body more than that of the valve head portion
Implementation Method 2
the valve head portion satisfies a relationship of r>0.6D0 where r is a curvature radius of the valve head portion and D0 is a seat diameter of the valve seat
Data Source
Figure 1
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AI summary
It is intended to provide a steam valve, which can reduce vibrations of each part of the steam valve, can suppress pressure loss and can cut off the steam rapidly. The steam valve 1 changes an area of a flow path between the valve seat 4 and the valve body 2 and adjusts a flow of steam passing through the flow path by moving the valve body 2 relative to the valve seat 4. The valve body 2 satisfies a relationship of r>0.6D0, where r is a curvature radius of the valve head portion 2A and D0 is a seat diameter of the valve seat 4. A tapered portion 2B is provided on an upstream side of the valve head portion 2A and its surface is tilted toward a direction of relative movement of the valve body 2 to the valve seat 4 more than that of the valve head portion 2A.