Control method for washing machine
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Solution Overview
Problem
Conventional washing machines have limited drum cleaning capabilities, struggling to effectively clean the outer and inner surfaces of the drum and tub, resulting in incomplete washing.
Innovation Solution
A control method that involves varying drum rotation speeds and water supply amounts, including steam injection and temperature control, to create a water current that cleans both the outer and inner surfaces of the drum and tub, with specific speed ranges and temperature settings to enhance hygiene and cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wash reinforcement nozzle sprays wash water into the drum, then the interior of the drum can be washed, but the spray range is restricted and the outer surface of the drum and inner surface of the tub cannot be cleaned
Solution Approach 1:
The cleaning function is divided into multiple nozzles positioned at different locations: a wash reinforcement nozzle for the drum interior, a door wash nozzle for the door, and circulation nozzles for the tub inner surface. This segmentation allows each nozzle to target specific areas, achieving comprehensive coverage without requiring a single nozzle to cover all areas.
Solution Approach 2:
The circulation nozzle is positioned inside the drum and directs water toward the tub inner surface, creating a nested cleaning path where water flows from the drum interior to the tub interior. This nested arrangement allows efficient use of space and enables cleaning of multiple surfaces through sequential water flow paths.
2Productivity
If the drum is cleaned by rotating at high speed, then cleaning efficiency improves, but water cannot generate sufficient friction current to clean the outer surface of the drum and inner surface of the tub
Solution Approach 1:
The drum rotation speed is dynamically adjusted during the cleaning cycle. The drum rotates at high speed (195-205 rpm) during washing to maintain cleaning efficiency, then slows to lower speeds (145-155 rpm, then 40-50 rpm) during drainage to generate sufficient friction between water and drum surface, enabling effective cleaning of the drum outer surface and tub inner surface.
Solution Approach 2:
The cleaning process uses periodic variations in drum rotation speed with multiple phases: high-speed rotation for washing, intermediate-speed rotation for first drainage and cleaning, and low-speed rotation for second drainage and final cleaning. This periodic speed variation ensures both high productivity during washing and sufficient friction force during drainage phases.
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
The method effectively sterilizes water and generates a cleaning current that evenly cleans both surfaces, improving hygiene and cleaning effectiveness.
Implementation Method 1
a heater is operated to sterilize water in a tub
Implementation Method 2
the rotating speed of a drum is controlled in this process to generate a water current moved upwards in a tub by friction with the drum
Data Source
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AI summary
Disclosed is a method of controlling a washing machine configured such that a drum having on a front surface thereof an inlet through which laundry is put is rotatably provided in a tub containing water. The control method includes (a) a step of supplying water to submerge at least a portion of the drum in the tub; (b) a step of performing at least once an operation in which the water contained in the tub is heated by operating a heater and the drum is rotated at a first set speed; (c) a step of draining the tub; (d) a step of supplying water to submerge at least a portion of the drum in the tub; and (e) a step of performing at least once an operation in which the water contained in the tub is heated by operating the heater and the drum is rotated. The step (e) includes a step of rotating at least once the drum at a second set speed which is lower than the first set speed; and a step of repeating a first drum cleaning operation in which the drum is rotated at least once at a third set speed lower than the second set speed, and a second drum cleaning operation in which the drum is rotated at least once at a fourth set speed lower than the third set speed.