Spray Arm Venturi Tube Layout for Higher Nozzle Pressure

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Solution Overview

Problem

Dishwashers face a challenge in achieving high hydraulic efficiency in their spray arms without increasing the external length of the Venturi tube, which would occupy valuable space needed for washing items.

Innovation Solution

The Venturi tube is designed to project into the spray arm's cavity, allowing its active length to be extended while maintaining the same external space requirement, by flaring continuously to its terminal end and forming a funnel-shaped profile, which optimizes the flow and pressure at the exit nozzles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If the Venturi tube is extended to increase pressure at exit nozzles, then hydraulic efficiency is improved, but the external length increases occupying space needed for washing items

Engineering Contradiction:

Improvepressure at exit nozzlesVSAvoidexternal length of Venturi tube

Core Design Contradiction:

Stress or pressureVSLength of stationary object

Solution Approach 1:

The Venturi tube is nested within the spray arm cavity, allowing the active length to be extended while the external length remains unchanged. The terminal end of the Venturi tube projects into the cavity enclosed by the spray arm, effectively placing one component inside another to resolve the space-pressure contradiction.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The solution moves the extension of the Venturi tube from the external dimension to the internal cavity dimension. By projecting the terminal end into the spray arm cavity, the pressure enhancement is achieved in the internal space rather than by extending externally, thus resolving the contradiction between pressure and external length.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the Venturi tube is made shorter to save space, then space for washing items is increased, but pressure at exit nozzles decreases reducing hydraulic efficiency

Engineering Contradiction:

Improveexternal length of Venturi tubeVSAvoidpressure at exit nozzles

Core Design Contradiction:

Length of stationary objectVSStress or pressure

Solution Approach 1:

Inventive Principle:

Principle #7Nested doll (Nesting)

3Productivity

If the Venturi tube flares continuously to terminal end, then hydraulic efficiency is maximized, but manufacturing complexity increases

Engineering Contradiction:

Improvehydraulic efficiencyVSAvoidmanufacturing complexity of Venturi tube

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The Venturi tube features a continuous flare from the narrowest point to the terminal end, forming a smooth curved profile. This rounded, funnel-shaped geometry optimizes hydraulic efficiency by eliminating abrupt transitions and dead zones, while the continuous curvature can be efficiently manufactured using standard molding or machining processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 configuration enhances the hydraulic efficiency of the spray arm, allowing for increased pressure at the exit nozzles without increasing the external space, while ensuring total drainage and minimizing dead volume, thus improving wash efficiency and water usage.

Implementation Method 1

the supply tube with its terminal end facing the spray arm projects into a cavity enclosed by the spray arm... the cross section of the Venturi tube flares continuously to its terminal end, the Venturi effect can be utilized up to a subregion of the height of the cavity of the spray arm

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentUS9032980B2Dishwasher comprising at least one rotatable spray arm

Publication Date: 2015.05.19 BSH HAUSGERATE GMBH

AI summary

A dishwasher includes a dishwashing compartment and a rack provided in the dishwashing compartment for holding items to be cleaned. A rotatable spray arm is associated with the rack for applying water or wash liquor liquid upon the items. Water or wash liquor liquid is supplied to the spray arm via an upright supply tube having at least one region which flares in a direction of the spray arm and a peripheral terminal end facing the spray arm. The terminal end of the supply tube is configured to project into the cavity and thereby is extended into the spray arm.