Pump Return-Flow Detection for Adaptive Installation Condition Control
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Solution Overview
Problem
The installation conditions of liquid-carrying household appliances, such as washing machines and dishwashers, affect the optimal operating point of pump elements, leading to sporadic spin failures and safety issues due to variable liquid columns, which existing methods struggle to accurately determine and adjust for.
Innovation Solution
A method that switches the pump element between a first operating state for conveying liquid out and a second operating state where the return flow is detected to infer installation conditions, using voltage, current, and frequency measurements to deduce the liquid column and adjust the pump speed accordingly, allowing for automatic setting of the optimal operating point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump element operates at a fixed operating point, then the device complexity is reduced, but the reliability deteriorates due to spin failures under variable installation conditions
Solution Approach 1:
The pump element's operating point is dynamically adjusted based on detected installation conditions. The control device modifies pump speed or power according to the detected liquid column height, transforming a static fixed-operating-point system into a dynamic adaptive system that maintains reliability across varying installation scenarios.
Solution Approach 2:
The system implements feedback by detecting the actual installation condition (liquid column height affecting pump performance) and using this information to adjust the pump operating point. The detection device monitors parameters like power consumption or flow characteristics, feeds this back to the control device, which then optimizes pump operation to prevent spin failures.
2Measurement precision
If the pump element speed is continuously increased to determine pumping height, then the measurement precision is improved, but the loss of energy increases
Solution Approach 1:
Instead of continuously increasing pump speed to maximum levels, the system applies partial action by incrementally adjusting speed only to the extent necessary to detect the pumping height. The detection process uses minimal speed increments sufficient to observe parameter changes, avoiding excessive energy consumption while maintaining adequate measurement precision.
Solution Approach 2:
The system replaces direct mechanical measurement methods with electrical parameter monitoring. Instead of mechanically measuring liquid column height, the system detects changes in electrical parameters (power, current, frequency) that correlate with pumping height, substituting mechanical measurement with electrical sensing to reduce energy consumption.
3Adaptability or versatility
If the appliance is installed outside defined optimal conditions, then the ease of operation is reduced, but the adaptability should improve to accommodate various installation locations
Solution Approach 1:
The system performs preliminary detection of installation conditions (liquid column height, pump backpressure) before the spin cycle begins. By detecting and adapting to the actual installation environment in advance, the system prepares optimal pump operating parameters, ensuring smooth operation even when installed outside defined optimal conditions.
Solution Approach 2:
The system changes operational parameters (pump speed, power, flow rate) based on detected installation conditions. By adjusting these parameters according to the actual liquid column height and backpressure, the system adapts to various installation locations, maintaining ease of operation across different environments rather than requiring strict adherence to optimal installation conditions.
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 method enables precise determination of installation conditions and automatic adjustment of the pump's operating point, preventing spin failures and ensuring safe operation by accurately accounting for the liquid column's influence on the pump element.
Implementation Method 1
a return flow of the liquid from the discharge line into the pump element is detected by means of the pump element
Implementation Method 2
a liquid is pumped out of the liquid reservoir from the liquid-carrying household appliance via the discharge line by means of the pump element
Data Source
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AI summary
Method for operating a liquid-carrying household appliance (1) with a pump element (2), a liquid reservoir (6) and a discharge line (4), wherein in a first operating state a liquid is pumped out of the liquid reservoir (6) via the discharge line (4) from the liquid-carrying household appliance (1) by means of the pump element (2) and in a second operating state a return flow of the liquid from the discharge line (4) into the pump element (2) is detected by means of the pump element (2), wherein a setup condition is inferred from the detected return flow.