Steam Turbine Seal Ring Fixturing for On-Site Outer Diameter Machining
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Solution Overview
Problem
Existing finishing apparatus and methods for steam turbine seal rings face challenges in securely clamping and machining the oversized seal rings due to their angled surfaces, leading to increased costs, time delays, and material wastage during installation.
Innovation Solution
A finishing apparatus with angled plates that form a wedge-shaped cavity to securely clamp and center the seal ring, allowing for precise reduction of the outer diameter using a lathe or other machining tools, ensuring a proper fit in the valve casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If known finishing apparatus are used to machine seal rings with angled surfaces, then the seal ring outer diameter can be reduced, but the seal ring cannot be securely clamped and positioned due to its angled surfaces and large size
Solution Approach 1:
The patent introduces a specialized finishing apparatus with a receiving cavity that acts as an intermediary between the seal ring and the lathe machining system. The cavity is shaped to complement the seal ring's angled surfaces, providing secure clamping and proper positioning without requiring direct contact between the lathe fixtures and the seal ring's difficult-to-grasp angled surfaces.
Solution Approach 2:
The finishing apparatus is divided into distinct functional components: a receiving cavity for secure clamping, a support structure for positioning, and a machining interface for the lathe. This segmentation allows each component to be optimized for its specific function, with the cavity geometry specifically designed to match the seal ring's angled surfaces for secure holding.
2Reliability
If seal rings are provided with an oversized outer diameter to ensure proper fit, then the seal ring can be manufactured with standard tolerances, but additional finishing work is required on site to reduce the diameter to match the valve casing inner diameter
Solution Approach 1:
The patent enables preliminary sizing of seal rings with generous tolerances during manufacturing, knowing that precise finishing can be performed later. The portable finishing apparatus allows this preliminary action to be reversed by enabling precise diameter reduction on-site, effectively combining the benefits of both approaches.
Solution Approach 2:
The patent replaces complex, time-consuming traditional on-site finishing methods with a streamlined system using a portable lathe and specialized finishing apparatus. This substitution reduces the time and labor required for on-site diameter reduction while maintaining precision.
3Manufacturing precision
If traditional finishing machinery is used for on-site seal ring finishing, then the seal ring can be machined, but the process is labor-intensive and costly
Solution Approach 1:
The finishing apparatus is designed with universal features that allow it to accommodate different seal ring sizes and configurations through the complementary receiving cavity design. The apparatus can be used with various lathe types and provides multiple functions including clamping, positioning, and machining support in a single integrated system.
Solution Approach 2:
The patent employs a portable, relatively simple finishing apparatus that can be set up and used quickly during turbine outages. The apparatus includes replaceable components such as the receiving cavity inserts that can be swapped to accommodate different seal ring geometries, reducing the need for complex, expensive, highly durable equipment.
Data Source
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AI summary
A finishing apparatus enables an outer diameter of a seal ring to be reduced. The finishing apparatus includes a first plate including a first peripheral angled surface, and a second plate including a second peripheral angled surface. The second peripheral angled surface is spaced a distance from the first peripheral angled surface when the finishing apparatus is assembled. The first and second peripheral angled surfaces define at least a portion of a wedge-shaped receiving cavity that is shaped complementary to a shape of an inner diameter of the seal ring to facilitate securing the seal ring in position relative to the finishing apparatus while the outer diameter of the seal ring is finished to a pre-determined size.