Single-Outlet High-Pressure Nozzle for Uniform Fire Spray

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Solution Overview

Problem

Existing high-pressure fire extinguishing systems using multi-hole atomiser nozzles suffer from non-uniform spray distribution, high water and energy consumption, and are costly to manufacture, while also posing risks due to small droplet dispersion and high velocities, which can be harmful upon impact.

Innovation Solution

A nozzle design featuring a single outlet with a swirling motion chamber and strategically placed openings to increase velocity and create a turbulent flow, resulting in a high degree of atomisation with smaller droplets, reducing velocity and improving uniformity, and made from durable materials to withstand high pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multi-hole atomiser nozzles are used to increase the number of droplets, then the degree of atomisation is improved, but the spray becomes poorly uniform and disperses on a relatively large surface

Engineering Contradiction:
Improvenumber of dropletsVSAvoidspray uniformity
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The nozzle uses a single outlet hole that segments the water stream into numerous droplets through hydraulic atomisation. The single hole design with optimized dimensions (diameter 0.5-2mm) and edge geometry creates a large number of small droplets (30-50 μm) while maintaining spray uniformity, avoiding the dispersion problems of multi-hole designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes critical parameters including the outlet hole diameter (0.5-2mm), the ratio between outlet diameter and chamber diameter (0.05-0.2), and the edge geometry (sharp edge with specific angles). These parameter changes enable high-degree atomisation with a single hole, achieving both high droplet count and spray uniformity.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the size of droplets is decreased to increase atomisation effectiveness, then the extinguishing effectiveness increases, but drag force increases and prevents advancement of the spray

Engineering Contradiction:
Improvedroplet sizeVSAvoiddrag force
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The invention optimizes droplet size parameters to achieve an optimal balance. The outlet hole diameter (0.5-2mm) and its ratio to chamber diameter (0.05-0.2) are specifically designed to produce droplets of 30-50 μm, which provides sufficient atomisation effectiveness while limiting drag force to acceptable levels for spray advancement.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If high pressure is used to atomise water, then the degree of atomisation increases, but the velocity of the spray increases making it harmful upon impact

Engineering Contradiction:
Improvedegree of atomisationVSAvoidspray velocity
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The invention uses specific geometric parameters to decouple atomisation quality from spray velocity. The outlet hole diameter (0.5-2mm), the sharp edge geometry (with specific angles), and the chamber dimensions create intense atomisation at high pressure while the geometry dissipates kinetic energy, reducing impact velocity to safe levels.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If known multi-hole atomiser nozzles are used, then sufficient extinguishing effectiveness is achieved, but they are expensive and difficult to manufacture

Engineering Contradiction:
Improveextinguishing effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention merges multiple functions into a single outlet hole design. Instead of using multiple separate holes that require precise alignment and are difficult to manufacture, a single hole with optimized dimensions and edge geometry performs atomisation, velocity control, and spray uniformity functions, significantly simplifying manufacturing while maintaining effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention changes from a multi-hole configuration to a single-hole configuration with specific optimized parameters (diameter 0.5-2mm, edge angles, chamber dimensions). This parameter change dramatically reduces manufacturing complexity and cost while maintaining or improving atomisation effectiveness through precise geometric control.

Inventive Principle:
Principle #35Parameter changes

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 nozzle achieves a high degree of atomisation with smaller droplets, reducing water consumption and energy use, while ensuring safety by slowing down the spray, meeting NFPA-750 standards and maintaining efficiency over time.

Implementation Method 1

The nozzle (1) may be supplied with a liquid L, preferably water, at high pressure

Methodology Applied
Scientific EffectHigh pressure: Pressure Increase

Implementation Method 2

configured so that the jet flowing out from the nozzle (1) is a spray of atomised liquid

Methodology Applied
Scientific EffectAtomisation: Fluid Spray

Implementation Method 3

strategically placed openings to increase velocity and create a turbulent flow, resulting in a high degree of atomisation with smaller droplets

Methodology Applied
Scientific EffectTurbulent flow: Turbulence

Implementation Method 4

a single outlet with a swirling motion chamber and strategically placed openings

Methodology Applied
Scientific EffectSwirling motion: Vortex Ring

Implementation Method 5

drag force is the main force which prevents the advancement of an atomised water spray in the air, and this friction increases as the size of the drops decreases

Methodology Applied
Scientific EffectDrag force: Drag

Data Source

PatentEP3981475B1High-pressure atomiser nozzle, lance including this nozzle and fire extinguishing system including this lance
Publication Date: 2023.11.08 CRISTANINI SPA
  • EP3981475B1 patent drawingFigure 1~2
  • EP3981475B1 patent drawingFigure 3
  • EP3981475B1 patent drawingFigure 4

AI summary

An atomiser nozzle which can be fluidically connected with means for supplying a high-pressure liquid (L) comprising an inlet (11) for the high-pressure liquid (L), an outlet (17) for the spray of atomised liquid and a fluidic connection line (10) extending between them. The fluidic connection line (10) comprises at least one first duct (14) fluidically connected with said inlet (11), an operating chamber (16) arranged downstream of said at least a first duct (12) and a plurality of first openings (15) for fluidically connecting the duct (14) and the operating chamber (16) configured so that the liquid (L) flowing out from the former (14) flows into the latter (16). The operating chamber (16) comprises a single outlet opening (17) with small section so that the liquid (L) flowing out therefrom is atomised liquid.