Dishwasher Rinse Recirculation for Cleaner Low-Water Final Rinsing

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Solution Overview

Problem

Dishwashers consume significant amounts of rinsing liquid and energy for heating, particularly due to the need for multiple rinse phases, which increases operating costs and environmental impact.

Innovation Solution

A dishwasher design that includes a recirculating rinse tank and a pump to reuse rinsing liquid, allowing for controlled recirculation and reduction in the quantity of clean final-rinse liquid needed, while maintaining cleanliness through a controlled pumping mechanism and liquid level sensor for efficient liquid management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If rinsing liquid is recirculated without controlled pumping, then rinsing liquid consumption is reduced, but the cleanliness of reused rinsing liquid deteriorates

Engineering Contradiction:

Improverinsing liquid consumptionVSAvoidcleanliness of reused rinsing liquid

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The system performs preliminary action by allowing the wash cycle to complete and the collecting device to accumulate rinsing liquid before initiating recirculation. The pump is activated only after washing is finished, ensuring that the liquid collected for recirculation has had time to settle and separate from food particles and detergent residues, thus maintaining cleanliness while reducing consumption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The collecting device acts as an intermediary between the spray arms and the recirculating rinse tank. It accumulates and holds the rinsing liquid, allowing for separation of clean liquid from contaminants before the liquid is pumped back into the system. This intermediary function ensures that only cleaner liquid is recirculated, maintaining reliability while improving substance efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If final-rinse liquid is supplied to a full recirculating rinse tank, then some final-rinse liquid is deprived of space and cannot be properly utilized, but clearing space requires additional operations

Engineering Contradiction:

Improveeffectiveness of final-rinse phaseVSAvoidtank management operations

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses a float valve as a feedback mechanism to automatically monitor the liquid level in the recirculating rinse tank. When the tank reaches its maximum capacity, the float valve automatically stops the inflow of liquid from the pump, preventing overflow and ensuring that final-rinse liquid has adequate space to function effectively. This automatic feedback eliminates the need for manual tank management operations.

Inventive Principle:

Principle #23Feedback

3Reliability

If a float valve with delayed opening is used to prevent first pre-rinse liquid from entering the recirculating rinse tank, then the recirculating tank remains cleaner, but the system complexity increases

Engineering Contradiction:

Improvecleanliness of recirculating rinse tankVSAvoidvalve control mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the rinsing process into distinct phases: wash cycle, initial rinse collection, and recirculating rinse phase. The collecting device is segmented as a separate accumulation chamber between the spray arms and the recirculating tank. This segmentation allows the first pre-rinse liquid to be collected separately during the wash cycle, preventing it from contaminating the recirculating tank, while using a simple float valve rather than a complex control mechanism.

Inventive Principle:

Principle #1Segmentation

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 rinsing liquid consumption, energy usage, and chemical costs, while ensuring a better wash result by maintaining cleaner rinsing liquid, thus providing economic and environmental benefits.

Implementation Method 1

a pump, which is arranged to pump used rinsing liquid from the collecting device to the recirculating rinse tank

Methodology Applied

Scientific EffectPumping: Pump

Implementation Method 2

spray members for spraying out washing liquid and rinsing liquid

Methodology Applied

Scientific EffectSpraying: Fluid Spray

Implementation Method 3

it to contain a drying agent, which reduces the surface tension of the rinsing liquid and thus makes it easier for the rinsing liquid to run off the wash items

Methodology Applied

Scientific EffectSurface tension reduction: Surfactant

Data Source

PatentUS8940107B2Dishwasher, and process for rinsing of wash items

Publication Date: 2015.01.27 WEXIODISK

AI summary

A dishwasher (10) for the batch washing of wash items (20) comprises a wash chamber (24), which is arranged to accommodate wash items (20) and in which spray members ((34a-b)) for spraying out washing liquid and rinsing liquid are disposed; a wash tank (28), which is arranged to contain washing liquid which during a wash phase shall be supplied to the wash chamber (24) via the spray members ((34a-b)); a recirculating rinse tank (52), which is arranged to contain used rinsing liquid which during a rinse phase shall be supplied to the wash chamber (24) via the spray members ((34a-b)); members (62) for supplying final-rinse liquid which during a final-rinse phase shall be supplied to the wash chamber (24) via the spray members ((34a-b)); a collecting device (42, 46), which is arranged to collect liquid which has been sprayed out into the wash chamber (24) via the spray members ((34a-b)); and a pump (48), which is arranged to pump used rinsing liquid from the collecting device (42, 46) to the recirculating rinse tank (52).