Hydro-blasting Anti-withdrawal Support for Recessed Tube Sheets
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Solution Overview
Problem
In shell-and-tube heat exchangers where the tube sheet is recessed within the shell, existing anti-withdrawal devices cannot be mounted in close proximity to the tube sheet, posing a safety risk during hydro-blasting operations due to the increased distance, which may cause the lance to withdraw accidentally, potentially injuring workers.
Innovation Solution
A hydro-blasting anti-withdrawal device support comprising a shell flange attachment plate, an AWD attachment plate, and a pipe that spaces these plates apart, allowing the anti-withdrawal device to be secured closer to the tube sheet, ensuring safe operation by maintaining the lance's position within the tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tube sheet is recessed within the shell, then the heat exchanger design is achieved, but the anti-withdrawal device cannot be mounted in close proximity to the tube sheet
Solution Approach 1:
A support structure with an attachment plate and positioning arm acts as an intermediary between the shell flange and the anti-withdrawal device. The attachment plate secures to the shell flange while the positioning arm extends toward the recessed tube sheet, enabling the anti-withdrawal device to be held in the correct position without direct mounting on the tube sheet.
2Ease of manufacture
If the anti-withdrawal device is mounted away from the tube sheet, then mounting is simplified, but the lance may withdraw accidentally causing safety risks
Solution Approach 1:
The support structure serves as a mediator that transfers the mounting function from the tube sheet to the shell flange, while simultaneously providing positional guidance through the positioning arm to ensure the anti-withdrawal device remains in the safe, correct position near the tube sheet.
Solution Approach 2:
The support structure replaces the direct mechanical mounting connection between the anti-withdrawal device and tube sheet with an indirect connection through the support structure, which provides both mounting capability and positional control.
3Ease of operation
If the distance between the anti-withdrawal device and tube sheet is increased, then mounting is easier, but the chance of lance withdrawal and worker injury increases
Solution Approach 1:
The positioning arm of the support structure acts as an intermediary that bridges the gap between the shell flange mounting location and the required proximity to the tube sheet, allowing easy mounting while maintaining safe distances.
Data Source
AI summary
The hydro-blasting anti-withdrawal device support is used for mounting an anti-withdrawal device (AWD) utilized when cleaning heat exchanger tubes in a shell-and-tube heat exchanger where the tube sheet is recessed within the shell. The support includes a shell flange attachment plate, an AWD attachment plate, and a pipe spacing the two plates apart. Each plate is substantially rectangular and has a pipe attachment tab extending therefrom, the pipe attachment tabs extending in opposite directions. In use, the shell flange attachment plate is secured to the shell flange, the anti-withdrawal device is secured to the AWD attachment plate, and the pipe is dimensioned to support the AWD in close proximity to the heat exchanger tube sheet.