Abrasive Blasting Nozzle Design for Noise Reduction

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Solution Overview

Problem

Conventional abrasive blasting systems produce excessive noise, leading to hearing loss and decreased situational awareness for operators, while also being large and heavy, causing ergonomic stress.

Innovation Solution

The development of reduced noise abrasive blasting assemblies and systems that incorporate a longer acceleration path for abrasive particles, using a combination of standard blast hoses, accelerator hose portions, transition couplings, and nozzles with straight sections to maintain particle velocity while reducing gas exit velocity and noise production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional supersonic nozzles are used for abrasive blasting, then productivity is maintained, but noise levels exceed safety limits and cause hearing loss

Engineering Contradiction:

Improvenoise exposureVSAvoidblasting efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The nozzle is divided into distinct functional sections: a convergent section for compression, a throat for sonic velocity achievement, and a divergent section for controlled expansion. This segmentation allows each section to optimize its function, reducing overall noise while maintaining particle acceleration efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from traditional short-nozzle designs to extended-length nozzles, adding dimensional length to the system. This extended geometry provides a longer acceleration path for abrasive particles, allowing supersonic flow to be contained within the nozzle rather than exiting immediately, thereby reducing external noise generation while maintaining productivity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If extended length nozzles are used to reduce noise, then noise levels decrease, but nozzle size and weight increase

Engineering Contradiction:

Improvenoise productionVSAvoidnozzle length

Core Design Contradiction:

Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The nozzle design optimizes the relationship between length, diameter, and wall thickness parameters. By carefully selecting these dimensional parameters, the nozzle achieves extended length for noise reduction while controlling overall size and weight through optimized cross-sectional dimensions and material distribution

Inventive Principle:

Principle #35Parameter changes

3Productivity

If supersonic flow is maintained for particle acceleration, then productivity is high, but noise levels increase

Engineering Contradiction:

Improveparticle velocityVSAvoidnoise generation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The extended nozzle acts as an intermediary device that mediates between the compressed gas source and the abrasive particles. It provides a controlled environment for supersonic flow development, allowing particles to be accelerated to high velocities while the nozzle structure contains and manages the supersonic flow to reduce noise generation

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

These systems achieve significant noise reduction, improving operator safety and situational awareness, while maintaining productivity and efficiency comparable to conventional systems, and reducing operator fatigue due to the lighter weight of the equipment.

Implementation Method 1

Gases mixed with abrasive media 18 are compressed when traveling through convergent section 32 and then dispersed through divergent section 36, causing media 18 particles to accelerate within the divergent section 36 of nozzle 26 and out therefrom.

Methodology Applied

Scientific EffectGas compression and expansion: Compression

Implementation Method 2

particles accelerate from fairly modest velocities before the nozzle, to higher velocities as the particles flow through the diverging portion of the nozzle and the exit

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS12280468B2Method and design for productive quiet abrasive blasting nozzles

Publication Date: 2025.04.22 KENNAMETAL INC

AI summary

Reduced noise abrasive blasting assemblies and systems are described. The new assemblies and systems are comprised of standard blast hose, accelerator hose, couplings and nozzle. The improved abrasive blasting system maintains abrasive particle velocity while decreasing the exit gas velocity and consequently decreasing sound production. This is accomplished through an acceleration section with reduced inner diameter and sufficient length to provide the necessary abrasive particle velocity. The new system maintains the productivity and efficiency of conventional abrasive blasting systems but with greatly reduced acoustic noise production and reduces operator fatigue due to the lower weight of the carried portion of the system.