Dishwasher Fill Detection Using Circulation Pump Power

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Solution Overview

Problem

Existing methods for operating water-bearing household appliances, such as dishwashers, lack a simplified mechanism to recognize when a storage container is fully filled with liquid, leading to inefficiencies and potential overflows.

Innovation Solution

A method that involves monitoring operating parameters of the circulation pump, such as electrical current or power consumption, to determine when the storage container is full, allowing the filling process to be stopped once predetermined threshold values are reached, thereby preventing overflows and ensuring complete filling before valve closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a storage container is filled with liquid until full, then the storage container achieves complete filling, but liquid overflow occurs causing harmful effects

Engineering Contradiction:
Improveliquid volume in storage containerVSAvoidliquid overflow
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The circulation pump is activated before the storage container filling process begins. This preliminary action ensures that when liquid reaches the storage container, it is immediately pumped away, preventing overflow. The pump creates a continuous liquid flow path that maintains the storage container at a controlled liquid level throughout the filling process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system monitors the operating parameters (current, power consumption) of the circulation pump in real-time during the filling process. When the pump's power consumption exceeds a predetermined threshold or fluctuates beyond an acceptable range, the control device interprets this as a signal that the storage container is full and automatically terminates the filling process, preventing liquid overflow.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If additional switches or sensors are added to detect full storage container, then detection precision improves, but device complexity increases

Engineering Contradiction:
Improvefull storage container detection accuracyVSAvoidnumber of additional components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The circulation pump serves a dual function: it not only circulates liquid during the washing process but also acts as an indirect sensor for detecting when the storage container is full. By monitoring the pump's own operating parameters (current, power consumption), the system uses the pump's self-characteristics as detection signals, eliminating the need for separate detection switches or sensors.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control device is designed to perform multiple functions: it controls the circulation pump operation, monitors the pump's power consumption, interprets the power consumption signals to determine storage container fill status, and terminates the filling process when needed. This multi-functional approach consolidates detection and control capabilities into existing components, avoiding additional hardware.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If the circulation pump runs continuously during filling, then liquid circulation is maintained, but power consumption increases

Engineering Contradiction:
Improveliquid circulation continuityVSAvoidcirculation pump power consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The circulation pump operates continuously during filling (excessive action to maintain circulation), but the system accepts the increased power consumption as a temporary necessary condition. The key is that this continuous operation is maintained only until the storage container is full, at which point the filling process is terminated. The increased energy use is thus limited to the filling duration and is considered acceptable for ensuring proper liquid circulation and preventing air pockets.

Inventive Principle:
Principle #16Partial or excessive action

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 allows for reliable identification of a full storage container without additional switches, ensuring efficient operation and preventing overflows by maintaining constant power consumption once the container is filled, thus optimizing the filling process.

Implementation Method 1

a circulation pump (23) for conveying the liquid (50) to the spray device (5)

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

a storage container (8) connected in a thermally conductive manner to the washing container (2) for storing liquid (48)

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP2194833B1Method for the operation of a water-conducting household appliance, and water-conducting household appliance
Publication Date: 2015.01.14 BSH HAUSGERATE GMBH
  • EP2194833B1 patent drawingFigure 1
  • EP2194833B1 patent drawingFigure 2
  • EP2194833B1 patent drawingFigure 3

AI summary

The invention relates to a dishwasher (1) and a method for operating a dishwasher (1) comprising a storage container, a washing receptacle (2), a spraying device (5) disposed inside the washing receptacle (2), and a circulation pump (23) for conveying liquid located in the washing receptacle (2) to the spraying device (5). The storage container (8) is connected to the washing receptacle (2) in such a way that excess liquid flows from the storage container (8) into the washing receptacle (2) when the storage container (8) is completely filled with liquid. The storage container (8) is filled with liquid, the circulation pump (23) is started, and at least one operational parameter (i) associated with the circulation pump (23) is monitored. The storage container (8) is no longer filled with liquid when the operational parameter (i) reaches a predefined threshold value (iS) and/or when the operational parameter (i) exceeds a predefined variation range.