Condensing Boiler Heat Exchanger Tubes With Self-Cleaning Turbulators

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Solution Overview

Problem

Heating devices using condensation heat exchangers for solid fuels face efficiency reduction and increased maintenance due to deposits and dirt buildup on heat exchanger tubes, which impairs heat transfer and requires frequent cleaning.

Innovation Solution

Incorporating a movable displacement cylinder with a helical turbulence body inside the heat exchanger tubes, which increases flue gas dwell time and contact with inner surfaces, and automatically lifts to loosen deposits, combined with a cleaning mechanism using a lifting device and cross members to reduce noise and enhance cleaning efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If flue gas remains inside the heat exchanger tubes for a long contact time to maximize heat transfer efficiency, then heat transfer efficiency is improved, but deposits and dirt build up on the inner surfaces of the heat exchanger tubes, impairing heat transfer and reducing efficiency over time

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidoperational reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent implements periodic mechanical cleaning action through a cleaning device that moves along the heat exchanger tubes at intervals. This periodic cleaning removes deposits before they significantly impair heat transfer, allowing the system to maintain high efficiency over extended periods while accommodating the necessary long contact time for heat exchange

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The cleaning device is designed to be self-propelled or automatically activated, moving along the heat exchanger tubes without requiring external intervention. The device uses the flow of flue gas or mechanical actuation to propel itself, performing maintenance functions autonomously and reducing operational downtime

Inventive Principle:
Principle #25Self-service

2Loss of energy

If a condensation heat exchanger is used to maximize heat transfer from flue gas, then combustion heat transfer efficiency is improved, but combustion particles in the flue gas form heavy deposits on all components in contact with the flow, increasing maintenance costs and susceptibility to faults

Engineering Contradiction:
Improvecombustion heat transfer efficiencyVSAvoidmaintenance complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent extracts the cleaning function as a separate, dedicated component that operates independently within the heat exchanger system. The cleaning device is introduced as a distinct element that removes deposits without interfering with the condensation heat exchange process, separating the maintenance function from the heat transfer function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cleaning device changes physical parameters such as mechanical force, vibration frequency, or flow dynamics to dislodge and remove deposits. By altering these parameters periodically, the system maintains clean heat exchange surfaces without requiring shutdown or manual intervention

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If the flue gas is cooled to below the dew point temperature to condense water vapor and recover heat of condensation, then efficiency is improved, but water vapor condenses and forms additional deposits on heat exchanger surfaces

Engineering Contradiction:
Improvecondensation heat recoveryVSAvoidcondensate deposit formation
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of condensation by directing the condensate flow to a collection system and using it for a beneficial purpose. The condensed water, instead of forming harmful deposits, is collected and can be used for pre-heating combustion air or other process purposes, transforming a waste product into a useful resource

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

Solution Approach 2:

The patent introduces an intermediary condensate management system between the heat exchanger and the environment. This intermediary system collects, separates, and manages the condensate, preventing it from forming deposits on heat exchange surfaces while recovering its thermal energy for useful applications

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution ensures a permanently efficient transfer of combustion heat to the heat transfer medium by preventing deposit buildup and maintaining high heat transfer efficiency, reducing maintenance efforts and extending the operational lifespan of the heating device.

Implementation Method 1

a helical spring-shaped turbulence body (15) is arranged between the inner surface of the heat exchanger tube (5) and the outer surface of the displacement cylinder (14), by which the flue gas can be swirled in its downward movement

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

downwardly directed heat exchanger tubes (5) of a condensation heat exchanger, in which the flue gas cools, giving off heat to the heat transfer medium surrounding the heat exchanger tubes

Methodology Applied
Scientific EffectHeat exchanger: Heat Exchanger

Implementation Method 3

the flue gas cools, giving off heat to the heat transfer medium surrounding the heat exchanger tubes, and from which the cooled flue gas exits at temperatures below the dew point temperature. Due to the cooling to below the dew point temperature, the water vapor contained in the flue gas condenses

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

the displacement cylinder (14) and the turbulence body (15) are movably mounted in the axial direction of the respective heat exchanger tube (5) by a lifting height H, whereby deposits can be loosened and fall in the direction of the discharge area (6)

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP3246652B1Heating device
Publication Date: 2020.02.19 OKOFEN FORSCHUNGS UND ENTWICKLUNGS M B H
  • EP3246652B1 patent drawingFigure 1a~1b
  • EP3246652B1 patent drawingFigure 2a~2b
  • EP3246652B1 patent drawingFigure 3

AI summary

The invention relates to a heating device, in particular a heating boiler, with a combustion chamber (1) for burning solid fuel, in particular biomass, and an adjoining flue gas duct (4) for removing flue gases, heat exchanger tubes (5) pointing downwards in the flue gas duct (4). of a condensation heat exchanger, the lower ends of which each open into a discharge area (6) for the condensate. According to the invention, it is proposed that a displacement cylinder (14) arranged coaxially with the respective heat exchanger tube (5) is provided inside the heat exchanger tubes (5), and that a helical spring-shaped one is provided between the inner surface of the heat exchanger tube (5) and the outer surface of the displacement cylinder (14). a turbulence body (15) designed with a coil spacing A, the displacement cylinder (14) and the turbulence body (15) being movably mounted in the axial direction of the respective heat exchanger tube (5) by a lifting height H which corresponds to the coil spacing A or exceeds it. In this way, a permanently efficient transfer of the combustion heat of solid fuels to the heat transfer medium is ensured with the help of condensation heat exchangers.