Underwater Stud Welding Tool With Inert Bell
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Solution Overview
Problem
Existing underwater stud welding devices face challenges such as inadequate drying of parts, water pollution from gas decomposition, non-magnetic material compatibility issues, and misalignment due to suction cup fixing systems, which hinder the quality and reliability of welds, especially in nuclear power plant environments.
Innovation Solution
A sealed welding tool with a mobile inerting bell that dries the stud and metal surface before welding and creates a pressurized gas atmosphere to prevent oxidation, eliminating the need for ceramic rings and ensuring proper alignment through a serrated bell design for effective water evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bell is used to create a gas atmosphere for underwater welding, then weld protection from water is improved, but water evacuation and drying of the welding zone becomes insufficient
Solution Approach 1:
The patent employs pneumatic principles by using compressed gas flows (argon or air) directed through specific nozzles to evacuate water from the welding zone. The gas flows create a dry environment necessary for welding by forcing water away from the stud and base metal contact area, thus resolving the contradiction between protecting the weld pool and effectively evacuating water.
Solution Approach 2:
The patent uses an inert gas atmosphere (argon or air) within the bell to protect the weld pool from oxidation and contamination. This inert environment allows the welding process to proceed reliably underwater while the separate water evacuation system ensures the welding zone remains dry, thus improving weld quality without compromising water removal efficiency.
2Reliability
If gas decomposition is used to protect the weld pool, then weld protection is improved, but water pollution increases
Solution Approach 1:
The patent replaces gas decomposition methods with an inert gas atmosphere approach. Instead of using chemicals that decompose and pollute water, the system introduces argon or air into the bell to create a protective atmosphere around the weld pool. This method provides effective weld pool protection without generating harmful byproducts or polluting the surrounding water environment.
Solution Approach 2:
The patent substitutes chemical decomposition methods with a physical/mechanical approach using compressed gas flows and pressure differentials to achieve weld pool protection. This replacement eliminates the harmful chemical reactions and water pollution associated with gas decomposition while maintaining effective protection of the weld zone.
3Ease of operation
If suction cup fixing is used for positioning, then ease of attachment is improved, but alignment precision deteriorates
Solution Approach 1:
The patent divides the positioning system into separate functional components: the suction cup provides attachment to the workpiece surface, while independent mechanical alignment features (such as guide pins, adjustable mounts, or laser alignment systems) ensure precise positioning of the welding tool. This segmentation allows each component to perform its specialized function optimally, resolving the contradiction between easy attachment and precise alignment.
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 solution enables high-quality, mechanically resistant welds without generating waste, suitable for various metal types and positions, and compatible with non-magnetic materials, ensuring reliable underwater stud welding in challenging environments like nuclear power plants.
Implementation Method 1
a first gas distribution circuit through which a first flow of gas can be sent into said bell to expel water at the surface zone of the part to be welded during welding
Implementation Method 2
a second circuit by which a second flow of gas can be sent in the direction of the front end of said stud so as to drive out any trace of humidity
Implementation Method 3
means for triggering an electric welding arc between a stud supported by said stud support and the surface of the part to be welded, and a bell mounted coaxially at the front of said box, the said bell comprising a main hollow bell body delimiting a second internal chamber capable of receiving the said stud on the said stud support and a gas capable of expelling a limited volume of water
Implementation Method 4
there is fusion of the two elements to be welded and they are then assembled. One of the characteristics of stud welding is the very short arc time (about 0.5 ms to 3000 ms) and the associated high heating and cooling rates
Implementation Method 5
Fusion and forging arc stud welding can be implemented mechanically or automatically, using a gun or welding heads. The stud is inserted into its support and, after possibly positioning a ceramic ring, it is brought into contact (A) with the part. At the start of the welding process, the stud is raised (B) by a mechanism and, in general, a pilot arc and then the main arc are established (C) between the end 10a of the stud and the part. This causes the end of the stud and part (D) to fuse together
Data Source
Figure 1A~1C
Figure 2
Figure 2A~2B
AI summary
The present invention relates to a tool for welding (1) underwater of stud (10) on a surface (11a), comprising (a) a box (3) containing a stud support (21) capable of sliding, in first relative translation with respect to the box (3) and (b) a bell (4) capable of receiving said stud (10) and a gas, and a coaxial orifice (4d) bordered by a crenellated ring (4c).The said bell (4) is capable of being moved in a second relative translation with respect to the said box (3) between (1a) a pre-docking position in which the said serrated ring (4c) is in contact with the surface (11a), and (1b) a docking position in which the front end (10a) of the said stud is abutted against the said surface of the part to be welded, and (c) two gas distribution circuits with a first gas flow (30) that can arrive at the said central orifice (4d) parallel to or at a first inclination of an angle α1 with respect to the axial longitudinal direction (XX'), and a second circuit (40-1, 40-2) through which a second gas flow can be sent radially or at a second inclination of an angle α2 with respect to the axial longitudinal direction (XX') greater than the angle α1 of the said first inclination α1, in the direction of the front end (10a) of said dowel.