Drain pump assembly for a washing machine appliance and methods of operating the same
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Solution Overview
Problem
Conventional washing machine appliances inaccurately detect water levels due to air bleeding in pressure sensors, leading to unnecessary drain cycles, increasing energy usage, cycle times, and noise.
Innovation Solution
A controller system that determines sump pressure thresholds and sets flags to selectively operate the drain pump only when necessary, differentiating between intentionally and unintentionally retained water, thereby optimizing drain cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the drain pump assembly operates at the beginning of every wash cycle to ensure accurate water level detection, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The system dynamically adjusts the drain pump operation based on detected conditions. The controller monitors sump pressure and flag status, operating the drain pump only when necessary (when pre-cycle drain flag is set) rather than following a fixed schedule, thereby optimizing energy consumption while maintaining detection accuracy.
Solution Approach 2:
The controller uses feedback from the water level detection system (pressure sensor readings and flag status) to make intelligent decisions about drain pump operation. By continuously monitoring sump pressure and comparing it against thresholds, the system determines whether a pre-cycle drain is necessary, avoiding unnecessary energy consumption while ensuring accurate water level detection when needed.
2Measurement precision
If the drain pump assembly operates at the beginning of every wash cycle to calibrate the pressure sensor, then measurement precision is improved, but cycle time increases
Solution Approach 1:
The system implements dynamic cycle timing by conditionally executing pre-cycle drain operations. When the pre-cycle drain flag is not set (indicating no water accumulation detected), the drain pump is skipped entirely, reducing cycle time. When the flag is set, the drain pump operates to calibrate the sensor and remove water, ensuring measurement precision. This conditional approach optimizes both time and accuracy.
3Measurement precision
If the drain pump assembly operates at the beginning of every wash cycle, then measurement precision is improved, but noise increases
Solution Approach 1:
The controller uses feedback from the water level detection system to intelligently control drain pump operation. By monitoring sump pressure and flag status, the system determines whether a pre-cycle drain is actually needed. When no water accumulation is detected (flag not set), the drain pump remains off, eliminating noise. When water is detected (flag set), the pump operates to ensure accurate detection, thereby reducing noise while maintaining measurement precision.
4Measurement precision
If the water level detection system continuously monitors sump pressure, then measurement precision is maintained, but use of energy increases
Solution Approach 1:
The water level detection system operates periodically rather than continuously. The controller checks sump pressure at key moments (before wash cycles, after drain cycles) based on trigger events rather than maintaining constant monitoring. This periodic operation maintains measurement precision at critical decision points while significantly reducing energy consumption during idle periods between cycles.
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
Reduces energy consumption, cycle duration, and noise by ensuring drain cycles are performed only when required, improving the accuracy of water level detection and reducing erroneous readings.
Implementation Method 1
a water level detection system fluidly coupled to the sump for measuring a sump pressure
Data Source
AI summary
A washing machine appliance and a method of selectively draining a sump of the washing machine appliance at the start of an operating cycle is provided. The method includes determining that the drain pump assembly has drained wash fluid from the sump, e.g., by checking to see whether an empty sump flag has been set in the controller. In addition, the method includes determining that a water supply valve has not been opened since the wash fluid was drained from the sump and that a sump pressure exceeds a predetermined threshold pressure, e.g., indicating that water is in sump that was not intentionally added by the water supply valve. The drain pump assembly is then operated to perform a drain cycle at the beginning of a subsequent operating cycle.