Speed-Controlled Pump Operation for Foam-Adaptive Spin Drainage
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Solution Overview
Problem
Washing machines face challenges in efficiently pumping out washing liquid during the spin phase due to foaming, leading to increased drive torques, motor wear, and reduced pump performance, especially when detergent residues cause foam formation.
Innovation Solution
A method where the power consumption and speed of the speed-controlled pump are dynamically adjusted based on the density of the pumped medium, with increased speed when foaming occurs and power consumption optimized to maintain efficient pumping, preventing water buildup and ensuring effective dewatering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pump operates at constant speed during spin phase, then the pump structure is simple, but pump performance deteriorates when foam formation occurs due to density reduction
Solution Approach 1:
The patent applies dynamics by transitioning from constant-speed pump operation to variable-speed operation. The pump speed is dynamically adjusted based on real-time detection of medium density (via power consumption monitoring), allowing the pump to adapt its performance to changing conditions during the spin phase, particularly when foam formation occurs.
Solution Approach 2:
The patent changes the operational parameter of pump speed from a fixed value to a variable parameter. By monitoring power consumption as an indicator of medium density and adjusting pump speed accordingly, the system optimizes pump performance across different operating conditions without requiring complex structural modifications.
2Productivity
If the pump speed is increased to compensate for density reduction due to foaming, then pump performance is maintained, but power consumption increases
Solution Approach 1:
The patent implements a feedback control mechanism where the pump's power consumption is continuously monitored to detect changes in medium density. This feedback information is used to adjust pump speed in real-time, optimizing the balance between maintaining pump performance and managing power consumption during the spin phase.
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 enhances pumping performance by adapting to changing conditions, reducing motor load, and preventing water backflow, resulting in improved spinning efficiency and faster achievement of desired residual moisture levels in laundry.
Implementation Method 1
a speed np of the speed-controlled pump is varied as a function of the density ρ of the pumped medium
Implementation Method 2
in a spin phase, which comprises in particular at least one centrifugal step
Data Source
Figure 1
AI summary
The invention relates to a method for operating a water-bearing household appliance 1 with a tub 2, a drum 3 for holding items of laundry 4, a drive motor 5 for the drum, a speed-controlled pump 18 which is connected to the tub 2 via a tub 23 and a Control device 8, wherein during a spinning phase, which includes at least one spinning step, the power consumption P of the variable-speed pump 18 is controlled as a function of the amount of water spun free, and wherein a speed np of the variable-speed pump 18 is varied as a function of the density p of the pumped medium. The invention also relates to a water-bearing household appliance 1 suitable for carrying out the method.