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 face inaccuracies in water level detection systems due to air bleeding over time, leading to unnecessary drain cycles, increased energy usage, longer cycle times, and higher noise levels.
Innovation Solution
A water level detection system with an air chamber and pressure sensor is used to measure chamber pressure after a drain cycle, setting a variable flag if the pressure exceeds a threshold, and operating the drain pump only if the flag is set, ensuring accurate water level assessment before starting a subsequent cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the drain pump assembly operates prior to every wash cycle to ensure accurate water level detection, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The system performs a preliminary drain cycle before the main wash cycle to ensure accurate water level detection. This preliminary action clears any residual water that might interfere with subsequent measurements, guaranteeing that the water level detection system starts with a known clean state without requiring continuous operation throughout the appliance's use.
Solution Approach 2:
Instead of continuously operating the drain pump assembly, the system implements periodic operation only at specific intervals - specifically before wash cycles when accurate water level detection is critical. This periodic approach maintains measurement precision while significantly reducing overall energy consumption compared to continuous operation.
2Measurement precision
If the drain pump assembly operates prior to every wash cycle to ensure accurate water level detection, then measurement precision is improved, but cycle time increases
Solution Approach 1:
The drain cycle is performed as a preliminary step before the main wash cycle begins. By completing the drainage and detection calibration beforehand, the system ensures accurate water level measurements are established prior to the time-sensitive wash operations, preventing delays during the actual washing process.
Solution Approach 2:
The system implements periodic drain cycles only when necessary - specifically before wash cycles requiring accurate water level detection - rather than continuously. This selective periodic operation minimizes the addition of cycle time to the overall washing process while maintaining measurement precision when it matters most.
3Measurement precision
If the drain pump assembly operates prior to every wash cycle to ensure accurate water level detection, then measurement precision is improved, but noise increases
Solution Approach 1:
The drain pump operation is performed as a preliminary action before the main wash cycle, completing the noisy drainage and detection calibration work beforehand. This timing strategy isolates the noise-generating activity to a specific preparatory phase, preventing noise interference during the actual washing operations when the appliance is in use.
Solution Approach 2:
The system implements periodic operation of the drain pump assembly only when accurate water level detection is required, rather than continuous operation. This reduces the total duration and frequency of noisy pump operation, significantly lowering overall noise levels and harmful acoustic emissions while maintaining detection accuracy when needed.
4Measurement precision
If the water level detection system continuously monitors water levels to ensure accuracy, then measurement precision is maintained, but use of energy increases
Solution Approach 1:
The water level detection system operates periodically rather than continuously - specifically activating before wash cycles to perform drain cycles and calibration. This periodic monitoring maintains measurement precision at critical moments while avoiding the excessive energy consumption that would result from continuous operation of the pressure sensor and associated systems.
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 reduces energy consumption, shortens cycle times, and minimizes noise by ensuring the drain pump operates only when necessary, providing a more accurate determination of water levels in the sump.
Implementation Method 1
a pressure sensor for measuring a chamber pressure
Data Source
AI summary
A washing machine appliance includes a sump for collecting wash fluid and a drain pump assembly for selectively draining that wash fluid in response to sump pressures measured by a water level detection system. Specifically, a controller is configured for operating the drain pump assembly to perform a drain cycle and obtaining a sump pressure after the drain cycle. A variable flag is set to a first state if the measured pressure exceeds a predetermined threshold pressure, which indicates that a certain amount of wash fluid is present in the sump. During a subsequent operating cycle, the drain pump assembly will be operated at the start of the cycle only if the variable flag was set to the first state during the prior operating cycle.