In-situ Sealing of Generator Fluid Cooled Conduit Brazed Joints
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Solution Overview
Problem
Brazed joints in fluid-cooled conduits of generators, containing phosphorus, corrode when exposed to water, leading to leaks and costly replacements due to differential thermal expansion and contraction, especially in large machines where complete replacement of phase leads, series loops, and connection rings is necessary.
Innovation Solution
An in-situ method involving the use of a borescope and sealant applicator to apply epoxy or powder coat paint directly to the inside of brazed joints in the fluid-cooled conduits, sealing them without disassembly, thereby preventing corrosion and leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If brazed joints containing phosphorus are used in fluid-cooled conduits, then manufacturing is simplified and cost is reduced, but corrosion and leaks occur when exposed to water
Solution Approach 1:
A sealant is introduced as an intermediary substance between the phosphorus-containing brazed joint and the water. The sealant applies to the external surface of the brazed joint, creating a protective barrier that prevents water from contacting and corroding the phosphorus-containing joint, thus maintaining both the ease of manufacture and reliability
Solution Approach 2:
The solution creates a composite protective structure by combining the original brazed joint material with an applied sealant coating. This composite system maintains the advantageous properties of the brazed joint (ease of manufacture, electrical conductivity) while adding corrosion resistance through the sealant layer
2Reliability
If complete replacement of phase leads, series loops, and connection rings is performed, then reliability is improved by eliminating corroded components, but cost and time increase significantly
Solution Approach 1:
The harmful element (water) is extracted or excluded from the system by applying a sealant barrier. This allows the existing brazed joints to be preserved rather than requiring complete replacement, maintaining reliability while avoiding the significant time loss associated with full component replacement
Solution Approach 2:
Instead of discarding the entire conduit assembly when corrosion is detected, the sealant application method allows recovery and continued use of the existing brazed joints. The protective sealant enables the original components to be retained, avoiding the time-consuming replacement process
3Reliability
If brazed joints are sealed with sealant, then corrosion and leaks are prevented, but the complexity of the sealing process increases
Solution Approach 1:
The sealant acts as a simple, easily applied protective layer that can be straightforwardly coated onto the brazed joints. This approach adds minimal complexity compared to the alternative of complete component replacement, providing an economical and simple maintenance solution
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
This method allows for the sealing of brazed joints in-situ, reducing downtime and replacement costs by preventing water ingress and corrosion, enabling the refurbishment of existing joints without the need for complete disassembly of the generator.
Implementation Method 1
A sealant is applied to an external surface of the brazed joint, thereby sealing the brazed joint.
Implementation Method 2
A sealant is applied to an external surface of the brazed joint
Data Source
AI summary
A method for sealing fluid cooled conduits in-situ for a generator is provided. The fluid or liquid cooled conduits are located external to a stator of the generator and substantially outward of stator bars. The method includes draining coolant from the fluid cooled conduits, and drying interior surfaces of the fluid cooled conduits. In inserting step inserts a borescope and a sealant applicator through an opening in one of the fluid cooled conduits. A locating step locates a brazed joint in the fluid cooled conduit, and a positioning step positions the borescope and the sealant applicator near the brazed joint. An applying step applies a sealant to the inside of the fluid cooled conduit at the brazed joint A viewing step may be used to view the brazed joint with the borescope to confirm that the applying step has been successful.