Pivot-Arm Duct Fastening for Leak-Tight Heat Exchanger Coupling
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Solution Overview
Problem
Existing fastening methods for coupling plenum boxes with heat exchangers are prone to premature failure due to thermal stress and operator error, and can cause buckling of the plenum boxes, leading to sealing issues.
Innovation Solution
A fastening device comprising a support member welded to the duct body, a pivot pin, and a locking device with a pivot arm, which engages the flange of the plenum to achieve a fluid-tight connection, reducing the impact of thermal stress and operator error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stud weld method is used to couple plenum boxes with heat exchanger, then coupling strength is improved, but reliability deteriorates due to thermal stress and operator error
Solution Approach 1:
The coupling system is divided into separate functional components: a support member welded to the heat exchanger body, a pivot arm that provides mechanical coupling, and a locking device that secures the connection. This segmentation allows each component to perform its specific function optimally while reducing stress concentration points.
Solution Approach 2:
The pivot arm acts as an intermediary element between the support member and the plenum box flange. It transfers and distributes the coupling forces, reducing direct stress on the weld joint and preventing premature failure from thermal stress and torque application errors.
2Ease of operation
If bolts and nuts are used to couple plenum boxes with heat exchanger, then ease of operation is improved, but structural stability deteriorates causing buckling
Solution Approach 1:
The pivot arm is designed to rotate about the pivot pin, providing dynamic adjustment capability during coupling. This allows the plenum box to be positioned and secured without requiring precise alignment and excessive tightening forces, preventing buckling while maintaining ease of operation.
Solution Approach 2:
The locking device replicates the securing function of bolts and nuts but distributes the clamping force through the pivot arm structure rather than concentrating it at single points, preventing local buckling while achieving the same operational ease.
3Device complexity
If locking device is positioned close to pivot pin, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
Instead of positioning the locking device along the radial axis close to the pivot pin, it is placed at an offset distance along the longitudinal axis. This dimensional shift allows sufficient space for the locking mechanism components while maintaining a compact overall structure, achieving both simplicity and manufacturability.
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 fastening device provides a reliable, fluid-tight connection between the duct bodies, reducing the risk of premature failure and buckling, while minimizing the impact of thermal stress and operator error.
Implementation Method 1
the support member is welded to the connecting edge of the first duct body
Data Source
AI summary
A fastening device for fluid tightly coupling a first duct body and a second duct body of a heat exchanger is provided. The fastening device includes a support member to couple with a connecting edge of the first duct body. The support member includes a pivot pin and a locking device disposed at an offset distance from the pivot pin along a radial axis of the fastening device. The fastening device further includes a pivot arm having a first end to engage with the pivot pin and a second end to engage with a flange of the second duct body. The locking device engages with the pivot arm and move the second end of the pivot arm relative to the pivot pin to fluid tightly engage the flange of the second duct body with the connecting edge of the first duct body.