DSI Dry Fog Dust Suppression System

What is Dry Fog?

To achieve agglomeration at the dust source, equal amounts of like sized particles of water droplets and dust particles must exist and they must be contained in an enclosed area.

At the treatment point, fog droplets are used to blanket the dust source and prevent the dust particles from becoming airborne.

Learn more about the key concepts of Dry Fog on the Dust Control Theory page.

Advantages

• Highly efficient and effective at reducing fugitive dust and suppressing respirable dust
• Low water use
• No chemicals
• Minimises wetting and overall moisture content of the material
• Returns useable material to the product stream
• Ease of installation
• Low maintenance 
• Flexible system configuration 

Why DSI Dry Fog?

DSI low flow, ultrasonic nozzles create fog droplets 1-10μm in size which easily agglomerate to dust particles as small as PM2.5 and PM10. These ultra-fine fog droplets add less than 0.1 percent of moisture by weight and attach to like size dust particles and drop them back into the process. When compared to alternative technologies, DSI Dry Fog’s ultra-fine atomization can agglomerate to the widest range of particle sizes due to its small droplet size. 

Wet Earth uses the DSI Dry Fog System because it is a robust, proven solution that has been used since 1997 in over 50 countries.

The DSI nozzles produce the finest droplets and have large throw distances compared to similar solutions from other vendors. Their nozzle enclosures provide robust protection to the nozzles and their complete solution simplifies installation. DSI nozzles are manufactured in the US and solutions are manufactured in a combination of the US and Australia.

The solution design utilises the experience of DSI’s engineers based in the US (who have designed thousands of systems) which ensure you get the best possible performance for your system.

DSI Dry Fog installations in Australia include:

• BHP Port Hedland Operations
• Citic Pacific Sino Iron
• FMG Cloudbreak and Christmas Creek
• Newcrest Cadia And Telfer Operations
• Newmont Boddington Gold
• First Quantum Ravensthorpe
• Glencore George Fisher, Mt Isa, Hail Creek and Townsville Port
  
  

The DSI Dry Fog System

DSI Dry Fog systems allow for flexible configuration with pre-assembled modular components. The type of application, type of bulk material creating dust, and operating environments are considered when customizing your system.

Housed in protective enclosures, we supply complete systems comprised of electrical controls, filtration, flow regulation, supply lines and nozzle mounts. If required, we can supply all necessary ancillary items including air compressors, air receiver stations, pumps, and self-cleaning secondary filtration systems.

Key system components are described in more detail below.

DSI Dry Fog Nozzles

DSI Dry Fog nozzles use a combination of focused compressed air and water and an external resonator to create an ultrasonic shock on the water particles to break them into a fine fog. They are commonly referred to as air atomising nozzles. The technology is illustrated in the following diagram.

The inlet water and air pressures for air atomising nozzles are relatively low (1 bar water and 5 bar air). It is possible to adjust these pressures to change the water droplet particle size and allow the fog to be 'drier' or 'wetter' depending on the material, application or other factors.

The DSI Dry Fog nozzles create droplets with a very small droplet size and a relatively low velocity which makes them ideal for capturing PM10 dust particles.

The DSI Dry Fog nozzle is the key element of the system converting the water into a dust suppressing fog. The nozzles are stainless steel and manufactured to exacting standards to ensure their performance. There are other ultrasonic air atomising nozzles available on the market, but most droplet sizes are well above the 1 to 10 micron size droplets that the DSI nozzles produce.

The following table provides an example of the droplet size distribution for the DSN-3 nozzle.

The following table lists the specifications for the range of DSI Dry Fog nozzles.

Universal Fogger Assembly

Ultrasonic air atomising nozzles are prone to damage due to the thin wire that supports the resonator. The Universal Fogger Assembly addresses this with the use of a robust enclosure for the nozzle as shown below. The enclosure also combines air and water lines into a single flexible hose from the supply enclosure.

Fogger Mounts

It is important to be able to install the nozzles so that they can be positioned and angled for optimum coverage. There are a range of Fogger Mounts that provide robust methods to position the Foggers so they are secure and easy to access.

Ball and Socket Mount

The Ball and Socket Mount allows the Fogger to be fitted from the outside of transfer points and angled to provide best dust suppression performance.

Angle Bracket Mount

The Angle Bracket Mount allows the Fogger to be connected to most surfaces and allow the Fogger to be angled to the direction which provides best performance.

Fogging Manifolds

The Fogging Manifolds provide a multi-directional stainless-steel housing for the fog nozzles which are then connected through one conduit to the Multi-Function Modules. The Fogging Manifolds have the following features:

• Heavy duty steel casing
• Easily mounted
• Factory fitted internal manifolding, single connection to Multi-Function Modules for easy installation
• Unidirectional nozzle mounts allow adjustment of the fog direction to where it is needed

Fogging Solution Modules

There are a range of modules that can be included in a DSI Dry Fog solution which depend on the project size and layout.

The key functions of these modules are:

• Filtration – typically multiple levels with self-cleaning function
• Pressure control of water and air – to ensure the ideal performance of the atomising nozzles.
• Electronic control – interface to other site systems
• Distribution of the water and air to each nozzle