Anchoring Claw Raised Areas Heat Exchanger Tube Grip
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Solution Overview
Problem
Existing anchoring claws for steam generator pipes in nuclear facilities face challenges in minimizing pipe rupture risk during removal, as they often cause excessive expansion of the pipe, which can lead to structural weakening and make it difficult to pull the pipe out or analyze defects effectively.
Innovation Solution
An anchoring claw with a hollow cylindrical clamping sleeve featuring raised areas on its radial outer surface, designed to form a form-fitting connection with the pipe wall, reducing the proportion of press-fit surfaces to 2-25% and using a pressure device to expand the sleeve, allowing for secure gripping without excessive pipe expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional anchoring claw with uniform press-fit surfaces is used, then the gripping force is distributed evenly, but the pipe experiences excessive radial pressure causing expansion and structural weakening
Solution Approach 1:
The clamping sleeve features raised areas (protrusions) that concentrate the gripping force onto specific localized zones of the pipe surface rather than distributing pressure uniformly. This local quality approach allows the anchoring claw to achieve sufficient grip force while minimizing the total radial pressure applied to the pipe, thereby preventing excessive pipe expansion and preserving structural integrity during the anchoring process.
2Force
If the clamping sleeve is expanded to increase gripping force, then the anchoring strength improves, but the pipe diameter increases making it difficult to pull through the base plate hole
Solution Approach 1:
By concentrating the anchoring function into localized raised areas rather than expanding the entire clamping sleeve circumference, the pipe diameter increase is minimized. The raised areas provide sufficient friction and mechanical interlocking for high tensile force resistance while keeping the overall sleeve expansion limited, allowing the pipe to pass through the base plate hole.
Solution Approach 2:
The clamping surface is segmented into discrete raised areas rather than being continuous. This segmentation allows the anchoring claw to achieve effective gripping through multiple localized contact points without requiring uniform expansion of the entire sleeve, thus limiting the overall diameter increase of the pipe.
3Reliability
If uniform pressure is applied across the entire clamping surface, then the anchoring is stable, but the pipe wall experiences high stress leading to rupture risk
Solution Approach 1:
The raised areas create localized high-pressure contact zones that provide stable anchoring through concentrated friction and mechanical interlocking, while the non-raised areas remain at lower pressure. This local quality distribution maintains anchoring stability without subjecting the entire pipe wall to uniformly high stress, thereby reducing the overall risk of pipe rupture.
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 anchoring claw effectively withstands tensile forces up to 4-5 tons with reduced radial pressure, minimizing pipe expansion and enabling reliable removal and analysis of steam generator pipes, while maintaining structural integrity.
Implementation Method 1
a hollow cylindrical clamping sleeve (52) made of a resilient material
Implementation Method 2
pressure means (74) being provided inside the clamping sleeve (52) to widen the diameter of the support area (14)
Data Source
AI summary
The invention relates to an anchoring claw (50) for heat exchanger tubes (46, 58), comprising a hollow cylindrical clamping sleeve (10, 32, 52, 102) made of a resilient material, wherein the clamping sleeve (10, 32, 52, 102) has at least one axially slotted (20, 92) support area (14, 34, 38) along its axial extension (12, 88, 126) and wherein pressure means are provided inside the clamping sleeve (10, 32, 52, 102) for expanding (18) the diameter (16) of the support area (14, 34, 38) in order to exert a pressure (110) from the radial outer surface (82) of the support area (14, 34, 38) of the clamping sleeve (10, 32, 52, 102). 102) to exert pressure on the inner wall (108) of a surrounding heat exchanger tube (46, 58) with an inner diameter (60) adapted to the outer diameter (56) of the clamping sleeve (10, 32, 52, 102).The radial outer surface (82) of the support area (14, 34, 38) has raised areas (22, 54, 86, 104), the total proportion of the raised areas to the total radial outer surface (82) of the support area (14, 34, 38) being in the range of 2% to 25%.