Dishwasher Spray-Arm Switching via Pump-Based Position Detection

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Solution Overview

Problem

Existing dishwasher technologies face challenges in detecting the current position of the reversing device, which is crucial for efficiently distributing washing liquid between spray arms, often requiring additional feedback mechanisms that increase complexity and cost.

Innovation Solution

The method involves using operating parameters such as hydraulic load, electric current, or power output from the circulating pump's drive to detect and control the reversing device's position, eliminating the need for special feedback contacts and allowing for simpler control device configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional feedback contacts are used to detect the reversing device position, then detection accuracy is improved, but device complexity and cost increase

Engineering Contradiction:

Improvereversing device position detection accuracyVSAvoidfeedback mechanism complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The circulating pump serves dual functions: it both circulates washing liquid and provides position information for the reversing device through its operating parameters. The pump's own operational characteristics (current, power, hydraulic load) are utilized to detect the reversing device position, eliminating the need for separate feedback contacts.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical feedback contacts with an electrical/operational parameter-based detection system. Instead of using physical contacts to detect position, the system monitors operating parameters (current, power, hydraulic load) of the circulating pump to infer the reversing device position, thereby reducing mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Difficulty of detecting and measuring

If special feedback contacts are added for position detection, then position detection capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvereversing device position detection capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Difficulty of detecting and measuringVSEase of manufacture

Solution Approach 1:

The circulating pump is made multi-functional by using it both for liquid circulation and for position detection purposes. The existing pump and its monitoring infrastructure serve dual purposes, eliminating the need for additional specialized components for position detection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the circulating pump's own operating characteristics to detect the reversing device position. The pump effectively 'reports' its own operational state through parameters like current and power, which the control device uses to determine reversing device position without requiring external feedback mechanisms.

Inventive Principle:

Principle #25Self-service

3Device complexity

If operating parameters of the circulating pump are used for position detection, then device complexity is reduced, but measurement precision may be affected by hydraulic load variations

Engineering Contradiction:

Improvecontrol system complexityVSAvoidposition detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The control device continuously monitors operating parameters of the circulating pump and uses this feedback information to detect the reversing device position. By establishing correspondence between operating parameters and reversing device positions, the system achieves accurate detection through continuous parameter monitoring and comparison.

Inventive Principle:

Principle #23Feedback

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 enables cost-effective detection and control of the reversing device's position, reducing tolerance variations and allowing for efficient liquid distribution between spray arms, thereby enhancing dishwasher operation without the need for additional feedback inputs.

Implementation Method 1

a corresponding hydraulic load is generated at the circulating pump depending on to which of the spray devices the circulating pump delivers liquid

Methodology Applied

Scientific EffectHydraulic load: Pressure Drop

Implementation Method 2

The circulating pump is driven by the first drive, which can be e.g. a first electric drive. In the case of the first electric drive the operating parameter can be an electric current, an electric voltage, an electric power output, a torque and/or a rotational speed of the electric drive

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentUS8268088B2Dishwasher and method for operating a dishwasher

Publication Date: 2012.09.18 BSH HAUSGERATE GMBH

AI summary

A dishwasher, including: a washing container; at least two spray devices disposed inside the washing container; a circulating pump to deliver liquid to the at least two spray devices; a first drive to drive the circulating pump; a reversing device, wherein, based on a position of the reversing device, the circulating pump delivers the liquid to at least one of the at least two spray devices; and a control device to detect a current position of the reversing device based on an operating parameter assigned to the first drive and to at least one of control and regulate the first drive.