Field Sprayer Nozzle Reducer Prevents Air Bubbles

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Solution Overview

Problem

Field sprayers experience issues with air bubble formation in the spray agent filters, leading to impaired pressure build-up and a lack of desired spray cone formation, especially at higher modulation frequencies or when filters are omitted due to poor water quality or cost considerations, which affects the distribution of the spray agent.

Innovation Solution

A nozzle arrangement with a reducer having a reduced line cross-section and a central channel is introduced instead of the spray agent filter, reducing compressible buffer volumes and preventing air bubble formation between the valve and the spray nozzle outlet, ensuring proper pulse width modulation of the spray cone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spray agent filter is installed in the cavity to retain solids in the spray agent, then the spray agent is protected from impurities, but air bubbles form on the filter which act as a buffer volume and impair pressure build-up at the spray nozzle

Engineering Contradiction:
Improvespray agent filtrationVSAvoidair bubble formation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the harmful function of the filter (air bubble accumulation) while retaining its useful function (solid particle filtration). This is achieved by introducing a reducer with a central channel that allows spray agent flow but prevents air bubble accumulation, effectively separating the filtration function from the air trap function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The reducer acts as an intermediary component between the spray agent channel and the cavity. It mediates the flow of spray agent while preventing air bubbles from forming in the cavity, thus resolving the conflict between filtration and air bubble prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the spray agent filter is omitted to simplify the design or reduce costs, then the cavity is available without a filter, but air bubbles form more easily in the empty cavity and impair spray nozzle performance

Engineering Contradiction:
Improvenozzle arrangement simplicityVSAvoidair bubble formation
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The reducer serves multiple functions: it maintains the structural integrity of the nozzle arrangement, guides spray agent flow through its central channel, and prevents air bubble formation in the cavity. This multi-functionality allows the system to operate effectively without a separate spray agent filter.

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

Solution Approach 2:

The invention changes the geometric parameters of the cavity by introducing a reducer with specific dimensions (line cross-section area of 5-50 mm²). This parameter change transforms the cavity from an air bubble-prone space into a controlled flow path that prevents bubble accumulation.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If pulse width modulation is used to adjust spray flow rate at higher frequencies (20-30 Hz), then spray application precision is improved, but air bubbles form more frequently and impair pressure build-up

Engineering Contradiction:
Improvespray application speedVSAvoidair bubble formation
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The reducer is installed in advance in the cavity to prevent air bubble formation before pulse width modulation operates. This preliminary structural preparation ensures that when high-frequency modulation occurs, air bubbles do not accumulate to interfere with pressure build-up and spray cone formation.

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If reducers with slightly limited line cross-section are used, then some air bubble formation is reduced, but the line cross-section is still too large allowing air bubbles to form and affect spray dispensing

Engineering Contradiction:
Improveair bubble formation reductionVSAvoidspray agent flow rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention optimizes the line cross-section parameter of the reducer to a specific range (5-50 mm²). This parameter optimization balances two competing requirements: limiting the cross-section enough to prevent air bubble accumulation, while maintaining it large enough to ensure adequate spray agent flow rate for productive operation.

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 solution effectively prevents air bubble formation and ensures a consistent, pulsed spray cone by reducing buffer volumes and maintaining flow conditions, even without a spray agent filter, enhancing the distribution efficiency of the spray agent.

Implementation Method 1

A nozzle arrangement with a reducer having a reduced line cross-section and a central channel is introduced instead of the spray agent filter, reducing compressible buffer volumes and preventing air bubble formation

Methodology Applied
Scientific EffectCompressible buffer volume reduction:

Implementation Method 2

a valve for pulse-width modulated release of a spray

Methodology Applied
Scientific EffectPulse width modulation:

Implementation Method 3

it does not eject the desired spray cone... The spray then flows out of the spray nozzle at a comparatively low speed

Methodology Applied
Scientific EffectPressure build-up: Pressure Increase

Data Source

PatentEP3542906B1Field sprayer with nozzle assemblies
Publication Date: 2021.12.01 AMAZONEN WERKE H DREYER GMBH & CO KG
  • EP3542906B1 patent drawingFigure 1

AI summary

A nozzle arrangement for a field sprayer is described, comprising a nozzle assembly with a valve for pulse-width modulated release of a spray agent, followed by a spray agent channel and at least one connection for a spray nozzle, with a cavity for inserting a spray agent filter being formed downstream. Instead of the spray agent filter, a reducer is provided in the cavity, which has a smaller cross-sectional area for the spray agent flow than the cavity itself. This prevents the formation of air bubbles between the valve and the outlet of the connection. Consequently, compressible buffer volumes between the valve and the spray nozzle can be reduced at least to such an extent that proper pulse-width modulation of the spray pattern is ensured even with rapid modulation and frequent switching on/off of spray nozzles.