Road Milling Dust Extraction Venturi Pipe Design
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Solution Overview
Problem
Existing road milling machines suffer from dust and vapor contamination affecting operator safety and visibility, as the fan of the suction device is exposed to dirty air, leading to soiling and reduced effectiveness.
Innovation Solution
The implementation of a suction device with a Venturi effect using a first and second pipe section with different cross sections, where the fan is positioned on the clean side to prevent dirty air from flowing through it, and an intake duct that opens into the exhaust pipe to enhance air extraction, with the fan blowing air perpendicular to the pipe sections to create high flow velocity and separate coarse dirt particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan is positioned in the dirty area to directly extract contaminated air, then the extraction effectiveness is improved, but the fan becomes soiled with dust and vapors reducing its reliability
Solution Approach 1:
The exhaust pipe is divided into two distinct sections: a first pipe section with a larger cross-section where the fan is positioned in clean air, and a second pipe section with a smaller cross-section that channels contaminated air. This segmentation allows the fan to remain isolated from contaminants while still enabling effective extraction through the Venturi effect created by the cross-section transition.
Solution Approach 2:
The second pipe section with reduced cross-section acts as an intermediary element that creates a Venturi effect. This constriction zone accelerates air flow and generates negative pressure to draw contaminated air from the milling area, while the fan itself remains positioned in the clean first pipe section, thus mediating between the clean fan environment and the dirty extraction zone.
2Reliability
If the exhaust pipe has a constant large cross-section, then the fan operates in clean air, but the extraction efficiency of contaminated air is reduced
Solution Approach 1:
The exhaust pipe exhibits varying cross-sectional dimensions at different locations. The first pipe section maintains a larger cross-section for fan protection, while the second pipe section features a smaller cross-section specifically at the contamination intake zone. This local variation in geometry creates the necessary Venturi effect to enhance extraction efficiency without compromising fan cleanliness.
3Productivity
If the exhaust pipe cross-section is reduced to enhance Venturi effect, then extraction efficiency is improved, but the fan may be exposed to contaminated air
Solution Approach 1:
The exhaust pipe is segmented into a clean zone (first pipe section with larger cross-section) and a contamination zone (second pipe section with smaller cross-section). The fan is positioned exclusively in the clean zone, while the cross-section reduction occurs only in the second section where contaminated air is drawn in, thus achieving both efficient extraction and fan protection.
Solution Approach 2:
Instead of reducing the cross-section throughout the entire exhaust pipe (which would expose the fan to contaminants), the cross-section reduction is applied in reverse sequence: the fan operates in the larger cross-section clean air zone, and the Venturi effect is generated downstream in the smaller cross-section zone where contamination is intentionally drawn in.
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
Effectively extracts dust and vapors without soiling the fan, improving operator safety and visibility by keeping the fan clean and enhancing the extraction efficiency through the Venturi effect and gravity-assisted dirt separation.
Implementation Method 1
The present invention has the advantage that the Venturi effect is used to extract air contaminated with dust and vapors particularly effectively.
Implementation Method 2
coarse dirt particles in the contaminated air, which are too heavy to be carried along by the air, fall to the ground due to gravity and in this case fall downwards along the first and/or second longitudinal axis of the exhaust pipe towards the floor covering
Data Source
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AI summary
In a road milling machine (1), comprising a machine frame (6), at least three drive units (2, 3), wherein at least two drive units (3) are driven and at least one drive unit (2) is steerable, at least one milling drum (11) for processing the pavement (4), and at least one extraction device (12) for extracting air contaminated with dust and vapors, the extraction device (12) is provided to have at least one first exhaust pipe (13) with at least one first pipe section (24) having at least one first cross-section (26) and at least one second pipe section (20) having at least one second cross-section (22), wherein the second cross-section (22) is smaller than the first cross-section (26), wherein an intake duct (18) has an inlet opening (30) and an outlet opening, wherein the outlet opening (28) opens into the exhaust pipe (13) in the area of the second pipe section (20).wherein the air contaminated with dusts and vapors can be drawn in at the inlet opening (30).