Laundry-care appliance having a circulation system
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Solution Overview
Problem
Conventional laundry care appliances with circulation systems fail to ensure even wetting of laundry with washing suds due to constant pump output, leading to inadequate wetting of laundry, especially when the washing drum rotates rapidly, causing laundry to be pressed against the drum wall and resulting in insufficient wetting of items against the drum.
Innovation Solution
A laundry care appliance with a circulation system that uses a pump to introduce washing suds into the washing drum with varying pump pressures over time, corresponding to a sinusoidal change, and a pump frequency lower than the rotational frequency of the drum, ensuring different areas of the laundry are contacted by the suds for complete wetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pump operates at constant speed with constant flow rate, then the circulation system is simple to control, but the laundry cannot be evenly wetted when the drum rotates rapidly
Solution Approach 1:
The pump speed is made variable rather than constant. The control unit adjusts the pump speed dynamically based on drum rotation speed to maintain optimal flow rate through the nozzle, ensuring uniform laundry wetting even when the drum rotates rapidly.
Solution Approach 2:
The pump operating parameters (speed and flow rate) are changed according to drum rotation conditions. When drum speed increases, pump speed is adjusted to maintain appropriate injection characteristics, transforming the system from static to adaptive operation.
2Stability of the object's composition
If the pump delivers constant flow rate of washing suds, then the pump operation is stable, but the laundry pressed against the drum wall cannot be sufficiently wetted
Solution Approach 1:
The pump operates dynamically with variable speed rather than constant speed. The control unit continuously adjusts pump speed in response to drum rotation speed, allowing the system to adapt to changing centrifugal forces and maintain effective laundry wetting throughout the wash cycle.
3Manufacturing precision
If the pump pressure is increased to improve wetting coverage, then more laundry areas are contacted, but the energy consumption increases
Solution Approach 1:
Instead of operating at constantly high pressure, the pump speed and pressure are varied according to actual needs. The control unit adjusts pump parameters to match drum rotation speed, applying higher pressure only when necessary to achieve adequate wetting coverage, thereby reducing overall energy consumption.
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 ensures even and complete wetting of laundry by varying the location of washing suds within the rotating washing drum, improving washing performance and reducing wetting times, which can lead to shorter washing cycles and lower energy consumption.
Implementation Method 1
When the washing drum rotates rapidly, the centrifugal forces that occur may cause the laundry to be pressed against the drum wall of the washing drum
Data Source
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AI summary
The present invention relates to a laundry-care appliance (100) having a rotatably mounted washing drum (107) for accommodating laundry, having a tub (109) for accommodating washing detergent, wherein the tub (109) has an outlet opening (113) and an inlet opening (111), and having a circulation system (105), which fluidically connects the outlet opening (113) to the inlet opening (111), wherein the circulation system (105) comprises a pump (117) for pumping washing detergent into the washing drum (107). The pump (117) is designed to pump the washing detergent into the washing drum (107) at different pump pressures, within the same washing operation, so as to vary the location at which the washing detergent enters the rotating washing drum (107).