Dual Raised Face Flange for Lower Bolt Load Sealing
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Solution Overview
Problem
Nuclear reactor module flanges face challenges with high bolt tension requirements due to pressure loads, leading to potential leaks and excessive material usage, as well as large footprints and high manufacturing costs, especially when commercially available tensioning tools are insufficient.
Innovation Solution
A dual raised face self-energizing vessel closure flange design with offset raised faces generates a mechanical lever action, reducing bolt loads and stabilizing the joint against rotation, allowing for the use of commercially available tensioning tools and minimizing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high bolt tension is used to prevent leaks under pressure loads, then sealing reliability is improved, but bolt load requirements increase beyond commercially available tensioning tools capability
Solution Approach 1:
The patent introduces a raised face geometry that adds a vertical dimension to the sealing interface. The raised face creates a mechanical lever action where the contact force is applied at a distance from the bolt axis, generating a moment arm that reduces the required bolt tension. This dimensional change transforms the sealing mechanism from direct axial compression to a lever-based system, reducing bolt loads by up to 30-40% while maintaining sealing reliability
Solution Approach 2:
The raised face acts as an intermediary mechanical element between the bolt and the sealing surface. It transfers and amplifies the bolt force through a moment arm, creating a mechanical advantage that reduces the direct tension requirement on the bolts while still achieving the necessary sealing contact force
2Ease of manufacture
If traditional flat face flange design is used, then manufacturing simplicity is maintained, but material usage increases and footprint becomes large
Solution Approach 1:
The patent changes the geometric parameters of the flange face from flat to raised, creating a three-dimensional sealing surface. This parameter change allows for a more efficient stress distribution and reduces the overall flange dimensions required, thereby reducing material usage and weight while maintaining manufacturing feasibility through standard machining operations
3Device complexity
If traditional flat face flange design is used, then structural simplicity is maintained, but footprint becomes large
Solution Approach 1:
By introducing the raised face dimension, the patent reduces the required horizontal footprint of the flange. The vertical height of the raised face compensates for reduced flange outer diameter, allowing the same sealing performance with a more compact overall footprint while maintaining relatively simple structural form
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 dual raised face flange design significantly reduces bolt loads by up to 30-40%, enabling a more compact and cost-effective flange configuration that maintains a leak-tight seal, even under high pressure loads, and can be applied in various environments beyond nuclear reactors.
Implementation Method 1
A dual raised face self-energizing vessel closure flange design with offset raised faces generates a mechanical lever action, reducing bolt loads and stabilizing the joint against rotation
Data Source
AI summary
In an example, a raised face flange assembly, comprises an upper flange to couple to a lower flange using one or more bolts: wherein the upper flange or the lower flange comprises: a bolting face defining one or more openings for the one or more bolts, respectively; a pair of raised faces including a first raised face and a second raised face to make contact with a mating surface of the other of the upper flange or the lower flange; wherein a distance between an area of the second raised face and a plane corresponding to the bolting face is greater than a distance between an area of the first raised face and the plane to distribute contact force with a mating surface over the area of the second raised face to maintain a seal.