Dust Suppression
Our design and consultancy is backed up by our association as distributors of the following companies:
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| The Raring Corporation of the USA Agglomerated Dust Suppression |
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Transfer Point Dust Control
Primary Dump Hoppers
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MARC is the Australasian distributor of the Raring Corporation ADS patented dust suppression system.
ADS fog based dust control systems are an efficient, low cost method of controlling fugitive dust from crushing, screening, conveying, loading, and unloading activities in almost any bulk material handling application. They are as efficient as dust extraction systems with fabric filters or wet scrubbers but require only a fraction of the operating horsepower and maintenance costs
ADS systems are simple to install and operate and they require no secondary dust or sludge handling systems. |
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The principal of operation is based on the probability of like-sized water and dust particles colliding, agglomerating, and growing in size and mass. As the agglomerates become larger and heavier and they settle back onto their source where they are carried through the process without any special handling.
When the particles are significantly different in size, the larger particle displaces enough air to carry the smaller particle around it without collision.
An ADS system is comprised of a group of unique fog nozzles, their pressure and flow controls, air and water filters, and dust source enclosures. |
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Our compressed air driven FP series nozzles produce water droplets in the 0-30 micron range, ideal for capturing PM-10 dust particles. Three models are available with water flow rates from 1 to 18 gpm and corresponding air consumption ranging from 3 to 25 SCFM. Operating pressures are normally compatible with standard plant air and water supply pressures.
Controls are supplied in all standard voltages. PLC and relay logic systems are offered. Explosion proof models use air-actuated valves with remote electrical controls. Freeze protected models operate to –20 F and below without problems.
Dust enclosures are a critical part of an ADS system as they are for any other effective dust control technology. |
| To achieve optimum dust control at transfer points and at drop points from crushers and screens onto belt conveyors, The Raring Corporation has developed the following specification for the design of dust enclosures and related equipment. US patent #5,803,955 has been granted to The Raring Corporation protecting certain elements of our ADS dust control system that cause it to be a highly efficient fine particulate scrubber unlike any other on the market. |
ADS™ Dust Control Enclosure Design Specifications:
Belt enclosure dimensions: The length of belt enclosures upstream of a chute is measured from the intersection point of the enclosure and the chute. The length of the down stream (or outgoing) belt enclosure should be five times the enclosure width. This rule may be adjusted in unusual cases of conveyor speed, belt width, chute height, or fines and moisture content. The length of the up stream (incoming) belt enclosure should be at least one times the belt enclosure width. The height of the incoming and outgoing belt enclosures is measured from the top of the material on the belt in its “normal” flow condition to the top of the enclosure. The measurement should be one times the belt enclosure width to a maximum of 24”. Belts being fed by multiple chutes should be covered continuously between the chutes.
Dust seals: Skirt boards on belt enclosures must provide a tight seal to the belt. Conventional vertical dust seal 
designs do not work well. We recommend a dust seal system in which the rubber is angled to the belt so that it lays on the belt with positive force. This prevents dust and small rock from getting between the belt and the rubber which greatly reduces wear and provides a good seal against the positive air pressure within the belt enclosure. Recommended suppliers of this material include Svedala Skega, Dust Control Inc., and Asgco. The dust seal rubber must be protected from direct contact with the flow of larger rock. To do this, we recommend the use of internal rubber or steel wear plate liners.
Enclosure Baffles: The feature of our enclosure design that distinguishes it from standard practice is the use of internal baffles that create multiple dust suppression chambers within the enclosure. These baffles are simple rubber curtains hung through slots in the top of the enclosure. They distribute air flow within the enclosure, impose a small back pressure to reduce the flow of air, and provide collection surface for the moist dust. The use of baffles in conjunction with fog or water spray in conveyor enclosures (sometimes called stilling or expansion chambers) is protected under the patent sited.
Guaranteed Dust Control Efficiency: The dust control efficiency of an ADS system installed in a material transfer application has been measured by an independent testing service at 99.29%. TRC guarantees at least 97.5% dust reduction when systems are installed, operated, and maintained according to our instructions.
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The Problem: As at this Mexican copper mine, large truck dumps are generally one of the most severe dust problems in a typical minerals mining plant.
The truck dumps are generally in a windy spot, they are large and open, and they are subject to severe duty. And they are often built to accommodate multi-sided dumping.
Large truck dumps are the most difficult dust control challenge in most . |
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The Solution: Controlling dust from these types of application points requires a lot of thought and a lot of cooperation from operating and maintenance personnel.
First and foremost, the site has to be protected from the wind. Nothing will work without that. We generally apply wind fences for this purpose. See our wind fence page.
Third, a lot of fog is required to fill the hopper and to create a curtain that can contain the displaced air from the dump.
We often add water spray at the dump pocket for control of dust at the downstream stock pile. |
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The Result: In the absence of wind and when we are able to place enough nozzles close enough to the mass of air flow, we can achieve 80% dust control efficiency.
The design and placement of large truck dumps is critical to dust control. We recommend that dust control be a made an important consideration when dump pockets are designed and specified
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