Dishwasher Liquid Storage Tank Filling via Excess Pump Flow

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Solution Overview

Problem

Existing dishwashers face a conflict between achieving high-quality washes and efficient water and energy use, with washing liquid storage tanks adding production costs due to complex filling and emptying requirements.

Innovation Solution

A dishwasher design featuring a washing chamber with a circulation circuit, a circulation pump, a spray arrangement, a flow control device, and a storage tank connected via a conduit with a flow control valve, allowing excess washing liquid to be pumped from the circuit to the storage tank, reducing production costs while enabling efficient liquid collection and reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a washing liquid storage tank is added to store washing liquid for re-use, then water and energy consumption is reduced, but production cost increases due to complex filling and emptying components

Engineering Contradiction:
Improveenergy consumptionVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the storage tank filling function with the existing circulation pump by utilizing the pump's existing infrastructure (inlet and outlet connections). The storage tank is integrated into the circulation circuit, allowing the same pump to both circulate washing liquid through the spray system and fill the storage tank, thereby eliminating the need for separate filling and emptying components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The circulation pump is designed to perform multiple functions: it circulates washing liquid to the spray arrangement for the washing process and simultaneously fills the storage tank with washing liquid for later reuse. This multi-functionality reduces the need for additional components while achieving both water/energy conservation and maintaining relatively simple device architecture.

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

2Loss of substance

If a washing liquid storage tank with filling and emptying components is added, then washing liquid can be stored for re-use, but manufacturing cost increases

Engineering Contradiction:
Improvewashing liquid lossVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of substanceVSEase of manufacture

Solution Approach 1:

The storage tank is integrated into the existing circulation circuit, sharing the circulation pump and connection infrastructure. This merging approach allows the system to capture and reuse washing liquid without requiring separate filling and emptying mechanisms, thereby reducing manufacturing costs while minimizing washing liquid loss.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system automatically fills the storage tank during the washing cycle using the circulation pump's existing flow path. The tank is self-filling through the pressure differential created by the pump operation, eliminating the need for complex active filling mechanisms and reducing manufacturing complexity.

Inventive Principle:
Principle #25Self-service

3Productivity

If excess washing liquid is pumped to storage tank during spraying, then collection efficiency increases, but flow rate requirements increase

Engineering Contradiction:
Improvecollection efficiencyVSAvoidpump power
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The system pumps excess washing liquid to the storage tank in addition to the amount needed for spraying. The circulation pump operates at a flow rate higher than the spray arrangement's requirement, and the excess flow automatically directs to the storage tank. This partial/excessive action approach achieves efficient collection without requiring the pump to work at maximum capacity continuously.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically balances the flow distribution between the spray arrangement and the storage tank based on the pump's operating characteristics. The flow control valve and circuit design allow the system to adaptively allocate washing liquid to different destinations, optimizing collection efficiency while maintaining appropriate spray flow rates without excessive power consumption.

Inventive Principle:
Principle #15Dynamics

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 design allows for cost-effective manufacturing and efficient washing liquid collection and reuse, reducing water and energy consumption without extending wash cycle duration, and enables the use of collected liquid in subsequent cycles.

Implementation Method 1

a circulation pump with an inlet and a first outlet, arranged to pump washing liquid in said circulation circuit

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

a flow control device arranged to selectively control washing liquid flow to said first spray arrangement

Methodology Applied
Scientific EffectFlow control: Valve

Implementation Method 3

a first spray arrangement arranged to spray washing liquid into the washing chamber

Methodology Applied
Scientific EffectSpray: Spray

Implementation Method 4

a flow control valve arranged in the first conduit, having at least an open state and a closed state

Methodology Applied
Scientific EffectFlow control valve: Valve

Implementation Method 5

an actuator arranged to control the flow control valve between the open state and the closed state

Methodology Applied
Scientific EffectActuator:

Implementation Method 6

The delivery pressure of the pump is adjusted and set such that difference between hydrostatic pressures is equal upon reaching a desired wash liquid level

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Gradient

Data Source

PatentEP3073885B1Dishwasher and method for collecting washing liquid in a dishwasher
Publication Date: 2019.02.06 ELECTROLUX APPLIANCES
  • EP3073885B1 patent drawingFigure 1
  • EP3073885B1 patent drawingFigure 2

AI summary

A dishwasher (1) and a method (100) for collecting washing liquid in a dishwasher are provided. The dishwasher (1) comprises a washing chamber (2) with a sump (3), a circulation circuit (4), a circulation pump (5), a first spray arrangement (6a), a flow control device (7), a washing liquid storage tank (8) connected to the circulation circuit (4). The flow control device (7) is arrangable to control washing liquid flow to said first spray arrangement (6a) such that washing liquid is arranged to be sprayed into said washing chamber (2) with a first flow rate (12). The circulation pump (5) is arrangable to pump washing liquid with a second flow rate (13), which second flow rate (13) exceeds said first flow rate (12) such that excess washing liquid is arranged to flow from the circulation circuit (4) to the washing liquid storage tank (8).