Washing Machine Drain Pump Cycling to Prevent Thermal Overload
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Solution Overview
Problem
Washing machines with integrated drain pumps face issues such as excessive heating, premature termination of operating programs, and complex maintenance due to clogged or blocked pumps, leading to thermal overload and potential damage.
Innovation Solution
A method that activates the drain pump to partially pump out liquid to a first pump-off level, deactivates it after a predetermined time, and repeats the process if a critical operating state is detected, with a limited number of retries to avoid prolonged activation and allow the pump to cool down, thereby preventing thermal damage and facilitating blockage clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drain pump remains activated until the container is pumped down to a first pump-down level or maximum activation period is reached, then the container is effectively drained to prevent overflow, but the drain pump undergoes excessive thermal loading and may be damaged
Solution Approach 1:
The drain pump is operated in periodic cycles rather than continuously. The control unit activates the drain pump for a limited activation period, then deactivates it even if the first pump-down level has not been reached. This periodic operation allows thermal cooling between cycles, preventing excessive temperature buildup while still achieving effective drainage over multiple cycles.
2Temperature
If the drain pump is deactivated after pumping to a first pump-down level below the limit filling level, then the pump avoids thermal overload, but the container may not be sufficiently drained
Solution Approach 1:
The useful action of draining is continued through repeated activation cycles. Instead of achieving complete drainage in a single continuous operation, the control unit repeatedly activates the drain pump across multiple cycles. Each cycle pumps down the container to the first pump-down level, and through continuous repetition, the container is progressively drained without subjecting the pump to excessive thermal loading.
3Reliability
If the drain pump is repeatedly activated when critical operating states are detected, then overflow is prevented, but the pump may be thermally overloaded
Solution Approach 1:
The control unit implements periodic activation with mandatory deactivation periods between cycles. When a critical operating state is detected, the drain pump is activated for a limited activation period, then automatically deactivates regardless of whether the pumping objective is fully achieved. This periodic pattern prevents continuous operation and associated thermal energy accumulation, while still providing effective overflow protection through repeated intervention.
4Productivity
If the drain pump operates continuously to drain the container completely, then the container is fully emptied, but the pump suffers from thermal damage and reduced functionality
Solution Approach 1:
The drainage process is divided into multiple periodic cycles rather than one continuous operation. The control unit activates the drain pump for a limited activation period in each cycle, then deactivates it to allow thermal cooling. Through repeated cycles, the container is progressively emptied to the desired level while the pump maintains functionality by avoiding excessive thermal loading that would occur with continuous operation.
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 improves the operating behavior of the drain pump by preventing excessive heating, reducing unnecessary error messages, and enabling effective detection of malfunctions, thus protecting the pump from damage and ensuring reliable operation.
Implementation Method 1
the drain pump is activated in order to at least partially pump out a filling from a container of the washing machine
Data Source
Figure 1
AI summary
The invention relates to a method for operating a washing machine (1), in particular a laundry washing machine or dishwasher, in which a drain pump (4) of the washing machine (1) is activated to pump out a load from a container (2) of the washing machine (1) and the drain pump (4) is deactivated when a first draining level N1AUSNÜUNT or a predetermined activation time of the drain pump (4) is reached. This operating cycle, comprising a draining phase and a deactivation phase of the drain pump (4), is performed for a maximum of N, with 1 <N<NmaX, wiederholt, wenn zuvor ein kritischer Betriebszustand der Waschmaschine erkannt wurde. Eine Fehlfunktion der Waschmaschine (1) wird aber erst dann erkannt, wenn der kritische Betriebszustand zumindest wieder erreicht wird, nachdem der Betriebszyklus zumindest für eine Anzahl Nmax-1 wiederholt wurde.