Controlled Wrinkle Bends in Indirect Heat Exchanger Pressure Vessels

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Solution Overview

Problem

Conventional serpentine circuit tubes in indirect heat exchanger pressure vessels face challenges in withstanding high pressures due to complex bending processes that require internal mandrels, leading to increased costs, potential leaks, and reduced quality, especially when forming long tubes with multiple bends.

Innovation Solution

The use of serpentine circuit tubes with controlled wrinkled portions featuring alternating ridges and grooves, which reduce bend complexity, allowing for mandrel-free bending and enhancing structural rigidity to withstand internal pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional bending processes are used to form serpentine circuit tubes with multiple bends, then the tubes can be formed into the required serpentine shape, but the process requires internal mandrels which increases manufacturing complexity and cost

Engineering Contradiction:

Improveserpentine shape of circuit tubeVSAvoidbending process complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the bend by introducing a controlled wrinkled portion with alternating ridges and grooves. This modification to the bend geometry allows the tube to achieve the required serpentine shape without requiring complex internal mandrels, as the wrinkled portion provides the necessary flexibility and stress distribution.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The bend structure is created as a composite form combining a smooth outer surface with a wrinkled inner surface. This composite geometry, with the controlled wrinkled portion featuring alternating ridges and grooves, provides both the necessary flexibility for bending and the structural integrity to withstand internal pressure without requiring internal mandrels.

Inventive Principle:

Principle #40Composite materials

2Shape

If internal mandrels are used in the bending process, then the tubes can be formed with the required bends, but the manufacturing cost increases and potential leaks occur

Engineering Contradiction:

Improvebend formationVSAvoidleak-free operation

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The patent extracts and eliminates the internal mandrel from the bending process by redesigning the bend geometry. The controlled wrinkled portion with alternating ridges and grooves is introduced as an alternative feature that enables mandrel-free bending, thereby removing the source of potential leaks and reducing manufacturing complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Stress or pressure

If conventional bends are used in serpentine circuit tubes, then the tubes can be assembled, but the tubes lack sufficient structural rigidity to withstand high internal pressures

Engineering Contradiction:

Improveinternal pressure resistanceVSAvoidstructural rigidity of bend

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The controlled wrinkled portion is localized to specific regions within the bend, creating areas of alternating ridges and grooves that provide local structural reinforcement. This local modification enhances the bend's ability to withstand internal pressure while maintaining the overall flexibility needed for serpentine configuration.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12392562B2Indirect heat exchanger pressure vessel with controlled wrinkle bends

Publication Date: 2025.08.19 BALTIMORE AIRCOIL CO INC

AI summary

In one aspect of the present disclosure, an indirect heat exchanger pressure vessel is provided that includes an inlet header to receive a pressurized working fluid, such as water, glycol, ammonia, and/or CO2. The indirect heat exchanger pressure vessel includes an outlet header to collect the pressurized working fluid and a serpentine circuit tube connecting the inlet and outlet headers. The serpentine circuit tube permits the pressurized working fluid to flow from the inlet header to the outlet header. The serpentine circuit tube includes runs and a return bend connecting the runs. The return bend has a controlled wrinkled portion comprising alternating ridges and grooves. The alternating ridges and grooves strengthen the return bend and permit the indirect heat exchanger pressure vessel to facilitate working fluid heat transfer at a high internal operating pressure.