Manifold Through Holes for Brazing Defect Detection
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Solution Overview
Problem
Existing manifolds for heat exchangers, particularly in automotive radiators, face challenges in detecting defects in brazed connections between the cover and housing during manufacturing, leading to potential leaks and premature failure due to high operational pressures, which current testing methods fail to detect efficiently and effectively.
Innovation Solution
Incorporating through holes in the cover of the manifold allows for easy and quick detection of brazing defects during production, enabling identification of defective products before they reach end-users, thereby ensuring the integrity of the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a leak test is conducted at 1.3 x 16 MPa (20.8 MPa) to eliminate defective heat exchangers, then defective products are removed before installation, but small defects in brazed connections at interfaces of large surfaces are not detected
Solution Approach 1:
The patent applies local quality by creating through-holes at specific locations on the cover where brazing defects are most likely to occur. Instead of uniformly testing the entire surface, the invention places detection points (through-holes) strategically at critical brazing interfaces, allowing focused detection of local defects without requiring high-pressure testing of the entire manifold.
Solution Approach 2:
The invention segments the detection process by dividing the cover into multiple regions with through-holes positioned at different brazing interfaces. This segmentation allows independent detection of defects at each interface location, enabling precise identification of problem areas without testing the entire system as a single unit.
2Measurement precision
If a test is carried out at pressure of 25-30 MPa to detect defects in brazed connections, then detection accuracy improves, but manufacturing cycle time increases and sealing requirements for testing equipment become more stringent
Solution Approach 1:
The patent applies partial action by using a moderate test pressure (not the maximum 25-30 MPa) combined with the through-hole configuration. The through-holes concentrate the testing effect at critical locations, allowing adequate defect detection at lower pressures, thus reducing testing time and equipment requirements while maintaining sufficient detection capability.
Solution Approach 2:
The through-holes act as intermediaries that amplify the detection effect. They serve as localized pressure concentration points that make small brazing defects visible through coolant leakage, enabling defect detection at lower system pressures than would otherwise be required.
3Strength
If brazing of two relatively large surfaces (cover and housing) is performed to connect them, then structural integrity is achieved, but defects in the form of gaps occur causing leakage of cooling medium
Solution Approach 1:
The patent applies preliminary action by incorporating through-holes in the cover before the final brazing operation. These pre-positioned holes serve as built-in detection points that will reveal any brazing defects that occur during the connection process, allowing immediate identification and rework of problematic joints while the system is still under manufacturing control.
Solution Approach 2:
The through-holes enable the brazed joint to self-diagnose its own quality. The cooling medium that flows through the manifold naturally serves as the test fluid that will leak through any gaps in the brazed connection, providing automatic defect detection without requiring external testing equipment or complex inspection procedures.
4Reliability
If a complicated system for detecting micro-deformations is used to detect brazing defects, then detection capability improves, but the method becomes complex and time-consuming
Solution Approach 1:
The invention makes the manifold self-testing by using its own operating coolant to detect defects. The cooling medium that naturally flows through the system during normal operation serves as the test fluid, eliminating the need for separate detection systems, sensors, or complex measurement equipment.
Solution Approach 2:
The patent extracts the detection function from complex external testing systems and integrates it directly into the manifold structure itself through the through-holes. This extraction simplifies the overall system by removing the need for complicated detection equipment while maintaining effective defect detection capability.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The subject of the invention comprises a manifold (1), in particular for use in the heat exchanger (19), such as an automotive radiator. The manifold comprises the housing (4) having defined therein at least one longitudinal channel (5) and also plurality of slots (10) on one surface thereof, which slots (10) are in fluid communication with the longitudinal channel (5). The manifold also comprises cover (2) applied on the housing (4) having plurality slots (3) at positions corresponding to the positions of the slots (10) of the housing (4) and connected to the housing (4) by a brazed connection. The cover (2) is provided with through holes (20) for detecting leakage of the cooling medium through defects of a brazed connection between said cover (2) and the housing (4), wherein said through holes (20) are formed in areas of the cover (2) between the slots (3) thereof. The invention relates also to a heat exchanger, in particular an automotive radiator, comprising such manifold.