Dishwasher Flow Channel Layout to Prevent Sump Backflow

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Solution Overview

Problem

Dishwashers face issues with washing water flowing backward from the sump due to negative pressure, leading to drainage problems and potential damage to the flow channel unit, and there is a need for a solution that prevents water from flowing into a water softener and addresses siphon phenomena.

Innovation Solution

A dishwasher design featuring a flow channel unit with a water supply flow channel connected to both the tub and sump, and a drainage flow channel unit with a siphon brake mechanism, which exposes the water supply and drainage flow channels to atmospheric pressure to prevent backward flow and siphon effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the sump feed water type is used to supply washing water to the sump, then water can be supplied to the sump, but washing water flows backward and drains due to negative pressure when water pressure is temporarily low

Engineering Contradiction:
Improvewashing water supply to sumpVSAvoidwater flow stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

An atmospheric pressure communication hole is introduced as an intermediary element between the water supply system and the external environment. This hole allows atmospheric pressure to act on the water supply flow channel, serving as a mediator that counterbalances negative pressure and prevents water from flowing backward into the sump.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of negative pressure is extracted and addressed by separately introducing atmospheric pressure through a dedicated communication hole. This separates the water supply function from the pressure balancing function, allowing each to be optimized independently.

Inventive Principle:
Principle #2Taking out (Extraction)

2Quantity of substance

If the sump feed water type is used, then washing water can be supplied to the sump, but all washing water is drained due to siphon phenomenon when some water must remain

Engineering Contradiction:
Improvewashing water supplyVSAvoidwashing water retention
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The atmospheric pressure communication hole acts as an intermediary that disrupts the siphon effect by introducing atmospheric pressure into the flow channel. This prevents the continuous drainage caused by the siphon phenomenon and allows water to be retained in the sump when needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If water supply flow channel is connected to both tub and sump, then simultaneous water supply is achieved, but the flow channel unit is damaged by backward flowing water

Engineering Contradiction:
Improvewater supply efficiencyVSAvoidflow channel unit durability
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The atmospheric pressure communication hole provides preliminary anti-action by establishing a pressure balance before negative pressure can cause water to flow backward. This preventive measure protects the flow channel unit from damage by counteracting the harmful pressure differential before it can affect the system.

Inventive Principle:
Principle #9Preliminary anti-action

4Ease of operation

If drainage is performed by the sump, then drainage function is provided, but washing water flows backward from the sump

Engineering Contradiction:
Improvedrainage functionVSAvoidwater flow control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The atmospheric pressure communication hole serves as an intermediary that stabilizes the water level and prevents backward flow during drainage operations. By maintaining pressure balance, it ensures reliable water flow control while preserving the sump's drainage function.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution allows simultaneous supply of water to the tub and sump, prevents backward flow and siphon phenomena, and protects the flow channel unit from damage, while ensuring effective drainage and water circulation.

Implementation Method 1

a communication unit through which the water supply flow channel is exposed to external air

Methodology Applied
Scientific EffectAtmospheric pressure: Pressure Gradient

Implementation Method 2

a drainage flow channel unit connected to a drainage flow channel discharging washing water of the sump to the outside, the drainage flow channel unit guiding the discharge of the washing water stored in the sump

Methodology Applied
Scientific EffectSiphon phenomenon: Syphon

Data Source

PatentEP3329827B1dishwasher
Publication Date: 2021.12.29 LG ELECTRONICS INC
  • EP3329827B1 patent drawingFigure 1
  • EP3329827B1 patent drawingFigure 2
  • EP3329827B1 patent drawingFigure 3

AI summary

A dishwasher according to the present invention comprises: a tub providing a washing space; a sump communicating with the tub through a recovery hole, and storing washing water; and a flow path portion installed on one surface of the tub, and supplying washing water to the tub and the sump. The flow passage portion includes: a water supply passage connected to a water supply source and receiving washing water; a first flow passage connected to the water supply passage and receiving washing water, and supplying washing water to the tub; and a second flow passage connected to the water supply passage and receiving washing water, and supplying washing water to the sump. The present invention has the advantages in that washing water can be supplied simultaneously to the tub and the sump, and washing water flowing in reverse in the sump can be prevented even when there is negative pressure in washing water being supplied to the sump.