Household device for cleaning items of laundry and method for operating a household device
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Solution Overview
Problem
Modern washing machines face challenges in accurately determining the delivery rate of their circulation pumps due to the formation of two-phase foam-water mixtures, which complicates drainage and requires more precise control to prevent issues like air suction and reduced flow rates.
Innovation Solution
Incorporating a flow meter to detect the actual flow rate of the fluid, allowing the control device to account for both operating parameters of the pump and the measured values from the flow meter, enabling reliable determination of the delivery rate and operating state of the pump system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a circulation pump is used to convey fluid from lower to upper regions of the tub, then fluid circulation efficiency is improved, but accurate determination of delivery rate becomes difficult due to two-phase foam-water mixtures
Solution Approach 1:
The control device uses feedback from operating parameters (motor current, speed) to continuously monitor and determine the circulation pump's delivery rate. The system measures the actual operating state and adjusts control based on this feedback, enabling accurate determination despite the complex two-phase fluid conditions.
Solution Approach 2:
The system determines delivery rate by analyzing changes in operating parameters of the circulation pump's motor (current, speed, power consumption). By monitoring how these parameters change under different operating conditions, the control device can infer the actual delivery rate even when direct measurement is difficult due to foam-water mixtures.
2Productivity
If the pump operates at high speed to improve drainage, then drainage efficiency is improved, but air suction and snorkeling operations occur reducing flow rate
Solution Approach 1:
The control device monitors operating parameters in real-time and uses this feedback to detect when snorkeling or air suction occurs. When such conditions are detected (through characteristic changes in current, speed, or power consumption patterns), the system can adjust pump operation to maintain stable flow rate and prevent reliability issues.
Solution Approach 2:
The system dynamically adjusts pump operation based on detected conditions. Rather than operating at fixed high speed, the circulation pump's speed and power are dynamically controlled to optimize drainage efficiency while preventing air suction and snorkeling, maintaining flow rate stability through adaptive operation.
Data Source
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AI summary
The invention relates to a household appliance (1) for the care of laundry items, comprising a tub (4) in which a washing drum (3) designed to hold the laundry items is arranged, and a pump system (7) which includes a circulation pump by means of which a fluid can be conveyed from a lower region (13) of the tub (4) to an upper region (14) of the tub (4). A control device (20) provided for controlling the circulation pump is configured to determine a delivery rate of at least the circulation pump based on at least one operating parameter of the circulation pump. The household appliance (1) includes a flow measuring device (23) by means of which the flow of the fluid through a line (16) of the pump system (7), through which the fluid can be supplied to the circulation pump, can be detected.The control device (20) is designed to take into account at least one measured value from the flow measuring device (23) when determining the delivery rate of the circulation pump. Furthermore, the invention relates to a method for operating such a household appliance (1).