Spiral-Flow Heat Exchanger Structure for Air Bubble and Scale Control

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Solution Overview

Problem

Conventional heat exchangers face inefficiencies due to air bubble adhesion on heat-transfer surfaces, leading to reduced heat exchange efficiency and scale precipitation, which complicates the configuration and increases costs with the need for additional components like pressure sensors and solenoid valves.

Innovation Solution

A heat exchanger design featuring an inner pipe with a spiral flow path and thickness projections that increase flow speed and shearing stress, using centrifugal force to wash away air bubbles and prevent their re-adhesion, thereby enhancing heat exchange efficiency and suppressing scale formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pressure control methods are used to remove air bubbles, then air bubble removal is achieved, but device complexity and cost increase due to additional components

Engineering Contradiction:
Improveair bubble removal effectivenessVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heat exchanger structure itself generates the necessary shearing stress through its geometric design (thickness projections in the flow path) to remove air bubbles, eliminating the need for external pressure sensors and solenoid valves. The system serves its own air bubble removal function through passive structural features rather than active control components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the physical parameters of the flow path (cross-sectional area, flow velocity, shearing stress distribution) by introducing thickness projections at specific locations. This geometric parameter modification creates localized high shearing stress regions that passively separate and remove air bubbles without requiring additional control systems.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional pressure control methods are used to remove air bubbles, then air bubble removal is achieved, but manufacturing cost increases due to additional components

Engineering Contradiction:
Improveair bubble removal effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The heat exchanger structure itself generates the necessary shearing stress through its geometric design (thickness projections in the flow path) to remove air bubbles, eliminating the need for external pressure sensors and solenoid valves. The system serves its own air bubble removal function through passive structural features rather than active control components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention replaces expensive electronic control components (sensors, valves, controllers) with a simple geometric feature (thickness projections) that can be integrated into the heat exchanger manufacturing process at minimal additional cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If air bubble adheres to heat-transfer surface, then heat exchange efficiency deteriorates, but scale precipitation also increases locally

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidscale precipitation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention uses the harmful effect of high-velocity flow (which could cause erosion) by directing it through thickness projections to create controlled shearing stress zones. This converts potentially damaging high-velocity flow into a beneficial force that removes both air bubbles and prevents scale formation at critical locations.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The thickness projections are strategically placed at specific locations where air bubbles tend to accumulate and where scale precipitation is most problematic. This creates localized zones of high shearing stress precisely where needed to remove air bubbles and prevent scale, without affecting the overall heat transfer surface area.

Inventive Principle:
Principle #3Local quality

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

This design achieves high heat exchanging efficiency while simplifying the configuration and reducing costs by effectively removing air bubbles and preventing scale precipitation, thus improving the heat exchanger's performance.

Implementation Method 1

since centrifugal force is applied to the first fluid which flows through the spiral flow path, air bubble having smaller density than that of the first fluid is washed away relatively toward the shaft

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

flow speed and shearing stress of the first fluid can be increased at predetermined intervals. Therefore, it becomes easy to wash away air bubble which is precipitated on and adhered to a wall surface of the spiral flow path

Methodology Applied
Scientific EffectShearing stress: Shear Stress

Implementation Method 3

a heat exchanger which exchanges heat between low temperature liquid and high temperature liquid

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3754284B1Heat exchanger and refrigeration cycle device
Publication Date: 2022.03.23 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3754284B1 patent drawingFigure 1A
  • EP3754284B1 patent drawingFigure 1B~2
  • EP3754284B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention provides a heat exchanger (32) including: an inner pipe (1); an insertion body (2) inserted into the inner pipe (1); and at least one or more outer pipes (3) provided around an outer periphery of the inner pipe (1) and through which second fluid flows, wherein the insertion body (2) is formed from a shaft (21) and a projection (22) formed on an outer surface of the shaft (21), first fluid flows through a spiral flow path (23) formed from at least an inner surface of the inner pipe (1) and the projection (22), and a plurality of thickness projections (22b) are provided on the spiral flow path (23) at predetermined intervals in a flowing direction of the first fluid, and a flow path area of the spiral flow path (23) is made small at the predetermined intervals in the flowing direction of the first fluid by each of the thickness projections (22b). According to this, the heat exchanger (32) can suppress the local precipitation of scale by simple means and heat exchanging efficiency can be enhanced.