Induction-Heated Washer Drum Steam Generation Without External Boiler
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Solution Overview
Problem
Conventional laundry machines with steam generators face issues such as high material costs, complex configurations, limited steam quality, and reduced energy efficiency due to the use of separate heating sources and external steam generators, which complicate steam generation and supply during washing, drying, and refreshing processes.
Innovation Solution
A laundry machine employing an induction heater to generate steam by spraying water onto the outer surface of a heated drum, eliminating the need for a sheath heater and external steam generator, and using a single inverter drive to control the output powers of two induction heaters for efficient steam generation and supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an external steam generator is provided to generate high-quality steam, then steam quality is improved, but material cost and device complexity increase due to additional components such as water supply, heat generator, sensor, safety device, and discharge part
Solution Approach 1:
The patent combines the steam generation function with the existing sheath heater by enabling it to operate in both immersion heating mode and steam generation mode. The sheath heater serves dual purposes: heating wash water when submerged and generating steam when positioned to contact the drum outer surface, thereby eliminating the need for a separate external steam generator and its associated components
Solution Approach 2:
The sheath heater is designed with multi-functionality to perform both wash water heating and steam generation tasks. By controlling the water level and heater position, the same heating element can effectively serve multiple functions within the washing machine system, reducing overall device complexity
2Productivity
If an external steam generator is used to generate steam, then steam generation capability is improved, but energy efficiency decreases due to heat loss during steam transfer through connection pipes
Solution Approach 1:
The invention extracts the steam generation function from the water heating function by enabling the sheath heater to directly contact the drum outer surface and generate steam in the space between the drum and tub. This separates the steam generation process from the water heating process, allowing steam to be generated directly at the target location without requiring transfer through connection pipes, thereby minimizing heat loss
3Ease of manufacture
If a conventional sheath heater is used to heat wash water and generate steam, then material cost is reduced, but steam generation is limited due to the need to maintain heater protection water level
Solution Approach 1:
The patent introduces dynamic control of the sheath heater operation by adjusting water levels and heater positions based on the operational phase. During washing, the heater operates in immersion mode to heat water; during steam generation phases (drying, refreshing), the water level is adjusted to allow the heater to contact the drum outer surface. This dynamic adaptation enables the conventional heater to effectively perform multiple functions without requiring additional components
4Loss of energy
If steam is generated by heating wash water with a sheath heater, then energy efficiency is improved by heating less water, but steam quality decreases to wet steam instead of high-quality steam
Solution Approach 1:
The invention applies preliminary heating action by heating the drum outer surface (heating surface) before water is sprayed onto it. The induction heater first raises the temperature of the drum surface to a high level, and then water is sprayed onto this pre-heated surface to instantly vaporize and generate high-quality steam. This preliminary heating ensures that the steam generated is dry and high-quality rather than wet steam, while still maintaining energy efficiency by heating a minimal amount of water
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 reduces manufacturing costs, minimizes operating time for steam generation, ensures high-quality steam production, and prevents hot water from entering the drum, while allowing simultaneous steam generation and supply without additional hoses, thus optimizing energy use and process efficiency.
Implementation Method 1
an induction heater provided in the tub and configured to heat a heating surface of an outer surface of the drum
Implementation Method 2
a spray nozzle configured to spray water in droplet form to the heating surface of the drum to generate steam
Data Source
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AI summary
Disclosed herein is a laundry machine. More particularly, a laundry machine for generating steam by an induction heater and a control method thereof are disclosed. The laundry machine may include a tub, a drum rotatably arranged in the tub to accommodate an object and provided with a through hole on an outer circumferential surface thereof, a steam induction heater provided at a front upper portion of a front wall or a rear upper portion of a rear wall of the tub to heat a heating surface of the drum facing the steam induction heater, a motor driven to rotate the drum, a spray nozzle configured to spray water onto the heating surface facing the steam induction heater to generate steam, and a processor configured to rotate the drum to introduce the steam into the drum through the through hole in a space between the tub and the drum.