Side-Entry Fitting Prevents Sagging in Clamshell Heat Exchangers

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Solution Overview

Problem

During the manufacturing of clamshell heat exchangers, fittings tend to sag and slide due to weight and leakage issues caused by gaps between plates, which can lead to braze ring placement problems and leakage, necessitating a solution that prevents sagging, retains the braze ring, and holds plates together during brazing.

Innovation Solution

A side-entry fitting comprising a tube with a heat exchanger attachment end and a sleeve extending from the tube's outer surface, creating a space for receiving a conduit and featuring a stop and tab for secure coupling, allowing only axial movement while preventing vertical movement and leakage, and incorporating notches and steps for plate alignment and retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional fittings are used during brazing, then the heat exchanger can be assembled, but the fittings sag and slide out due to weight and liquid clad layer

Engineering Contradiction:

Improvefitting position stabilityVSAvoidfitting weight

Core Design Contradiction:

Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The fitting is divided into multiple components: a tube portion, a collar portion, and a braze ring. The collar acts as a separate supporting structure that prevents sagging, while the tube provides the functional flow path. This segmentation allows the supporting structure to bear the weight without compromising the fitting's operational integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The collar and braze ring are pre-positioned on the tube before brazing to the heat exchanger plates. The collar is initially placed to provide immediate support against sagging during the brazing process, and the braze ring is positioned to seal the gap between plates before the actual brazing occurs.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If the fitting is securely attached to prevent movement, then sagging is prevented, but axial movement is also restricted

Engineering Contradiction:

Improvefitting position stabilityVSAvoidaxial movement capability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The fitting design provides different degrees of freedom in different directions: it is rigidly constrained in radial directions (perpendicular to the tube axis) to prevent sagging, but allows free movement along the axial direction (parallel to the tube axis). This local differentiation of constraint quality enables simultaneous prevention of sagging and maintenance of axial adjustability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fitting transitions from a static, fully constrained design to a dynamic design that adapts its constraint characteristics based on direction. The collar provides dynamic support against radial displacement while permitting axial movement, allowing the fitting to maintain stability where needed and flexibility where required.

Inventive Principle:

Principle #15Dynamics

3Reliability

If flux paste or braze ring is used to seal the gap between plates, then leakage is prevented, but insufficient or improper placement causes leakage

Engineering Contradiction:

Improveseal reliabilityVSAvoidbraze ring placement precision

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The braze ring is pre-positioned in the gap between the heat exchanger plates before the brazing process begins. This preliminary placement ensures proper positioning and sufficient quantity of sealing material, eliminating the need for precise manual application during assembly and ensuring reliable sealing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The braze ring serves as an intermediary sealing element that fills the gap between the heat exchanger plates and the fitting. This intermediary component provides a reliable seal that is less sensitive to manufacturing tolerances and assembly variations compared to direct metal-to-metal contact or flux paste application.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Stability of the object's composition

If the fitting is designed to prevent sagging, then vertical movement is inhibited, but the structure becomes more complex

Engineering Contradiction:

Improveresistance to vertical movementVSAvoidfitting structure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The anti-sagging function is merged with the fitting structure itself rather than being a separate mechanism. The collar and braze ring are integrated components that form part of the fitting assembly, providing structural support while maintaining a relatively simple overall design that does not require additional active control systems or complex mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9664449B2System with heat exchanger with side entry fitting

Publication Date: 2017.05.30 DANA CANADA CORP

AI summary

A heat exchanger system containing a heat exchanger coupled to a fitting. The fitting contains a tube having a heat exchanger attachment end and an opposing end. The fitting further having a sleeve, having a sleeve body connecting a first end of the sleeve to an overlapping end. The first end of the sleeve being coupled to an outer surface of the tube and the sleeve body and the second end of the sleeve being spaced from the outer surface of the tube defining a space for receiving a conduit and adapted for coupling the fitting to the conduit. Also described is a fitting that can be attached to a conduit.