Continuous-Flow Heater Cleaning by Natural Circulation

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Solution Overview

Problem

Existing methods for cleaning systems, such as those used in cooking appliances, require additional pumps and complex designs, leading to increased manufacturing costs and reduced operational reliability.

Innovation Solution

A method that integrates a droplet separator as an integral part of the tank, allowing for natural circulation of cleaning liquids without the need for external pumps, and uses a temperature sensor to automate the cleaning process based on calcification levels, reducing the number of components and assembly steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If additional pumps are used for forced circulation of cleaning liquid, then cleaning effectiveness is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system uses natural circulation driven by temperature differences and density variations to circulate cleaning liquid without requiring external pumps. The heating element creates thermal convection currents that automatically move the cleaning liquid through the system, eliminating the need for mechanical pumping components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical pump system with a thermal convection-based circulation system. By using heat-induced density differences to drive fluid flow, the system substitutes mechanical energy input with thermal energy input, thereby eliminating moving mechanical parts while maintaining circulation functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If additional pumps and complex designs are used, then cleaning performance is improved, but operational reliability decreases

Engineering Contradiction:
Improvecleaning performanceVSAvoidoperational reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system achieves self-circulation through natural convection currents generated by temperature differences. This eliminates dependence on mechanical pumps that can fail, reducing the number of potential failure points and improving overall system reliability while maintaining cleaning effectiveness.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts and removes the pump component from the system entirely, relying instead on the inherent physical properties of heated fluids to provide circulation. This reduction in component count directly improves reliability by eliminating potential failure sources.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If more components are added to the system, then cleaning functionality is improved, but installation space requirements increase

Engineering Contradiction:
Improvecleaning functionalityVSAvoidinstallation space
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent combines multiple functions into existing system components. The heating element serves dual purposes: normal heating operation and driving natural circulation during cleaning. The fluid pathways are integrated into the existing system architecture, eliminating the need for separate pump assemblies and associated mounting space.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By utilizing the existing thermal field and fluid pathways for self-circulation, the system avoids adding separate circulation infrastructure. The natural convection currents use the same spaces and components already present in the system, requiring no additional installation space.

Inventive Principle:
Principle #25Self-service

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 approach simplifies the system design, reduces manufacturing costs, enhances operational reliability, and allows for demand-controlled cleaning, while maintaining a low noise level and efficient cleaning performance.

Implementation Method 1

the cleaning liquid is heated to a target temperature with the continuous-flow heater... the cleaning liquid flows through the continuous-flow heater in a natural circulation

Methodology Applied
Scientific EffectThermal convection: Convection

Implementation Method 2

The system consists of a tank for storing water and a continuous-flow heater for generating steam... the tank and the continuous-flow heater being connected to one another in a fluid-conducting manner on both the steam-side and the water-side end

Methodology Applied
Scientific EffectDroplet separation: Cyclone Separation

Data Source

PatentEP2048444B1Method for cleaning a system, composed of a tank and a continous-flow heater
Publication Date: 2016.02.24 MIELE & CO KG
  • EP2048444B1 patent drawingFigure 1~2
  • EP2048444B1 patent drawingFigure 3
  • EP2048444B1 patent drawingFigure 4

AI summary

The cleaning system (26) for a domestic oven has a water tank filled with diluted citric acid to a given level (40) and a continuous-flow heater (26.2) to generate steam. When the heater is activated, the water temperature is set to a nominal level to give a natural circulation. After a given cleaning time, further rinsing water is added while it is still circulating. After cleaning, the mixture of cleaning and rinsing fluids is spun out of the system.