Tuesday 9th Mar, 2021

Defeating dust with loading spouts

ABHR speaks to Laurence Millington, Vortex Global’s Managing Director to learn how loading spouts can reduce health risks and improve operations.

ABHR speaks to Laurence Millington, Vortex Global’s Managing Director to learn how loading spouts can reduce health risks and improve operations.

When moving dry bulk materials such as grain, coal, cement or rock, clouds of debris and dust form, which can pose risks to employee health.

Airborne dust not only causes chronic lung issues, eyesight problems and skin allergies, but can accumulate on top of elevated walkways, floors and ladder runs, making it easier to slip and fall. Additional labour is often required to clean up, further increasing costs.

Escaped dust also means material will be lost, which can lead to reduced profits over a long period of time.

Loading spouts are one way of mitigating this side effect of moving bulk materials from a silo or hopper into trucks, stockpiles, ships, barges or railcars. Spouts contain the flow of material into a confined area, reducing the radius of debris and dust.

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The spouts are made up of three distinct layers. The first is a series of internal stacking cones that can be constructed from materials like steel or polymer. On top of this is a fabric sleeve that encloses the cones to keep the dust inside of the system. An optional layer is a neoprene rubber skirt located at the bottom of the spout, which is typically used in open loading applications and rests on top of the stockpile where the material flows.

To fully control dust emissions during the loadout process, a fourth layer can be added. Loading spouts can be equipped with an in-line filtration system or integrated into an already existing dust filtration system. Using all four of these layers can drastically reduce dust emissions in comparison to using a sock.

Automation can also be included in a loading spout and can be outfitted with an aeration system to handle specific materials or desired flow rates.

Laurence Millington, Managing Director from loading spout manufacturer Vortex Global, says having a loading spout with a blower and integral filter can send the fugitive dust to draft back through the sleeve of the loading spout, trapping material dust temporarily in the filter cartridges.

“An automatic onboard pulse system dislodges the dust and fine particles, reintroducing them back into the product feed. It continuously purges the filters to keep the equipment working optimally and free of dust build-up. This prolongs the life of the filter cartridges significantly,” Millington says.

“Sensors attached to the inside of loading spouts can also automatically measure product levels, providing a signal that stops the flow of materials to prevent overfilling or plugging with the spout.”

Vortex loading spouts have a four-cable lifting design to provide as much stability as possible when compared with two or three cable systems. An in-line drive system also incorporates pulleys that feature chamfered edges and precision cable grooves to significantly reduce cable wear and back lashing as the loading spout extends and retracts, especially during the misalignment of the hatch opening. Because the cables do not fray, cable failure is nearly eliminated and so is costly downtime for repairs.

Spouts can also be fitted with single and dual-axis positioners. This becomes useful when trucks, railcars, and vessels don’t always line up in the exact same place. When loading enclosed trucks or railcars, this process can be automated utilising the hatch opening. The automated positioner can find the hatch and line up the spout accordingly.

Millington says the spouts can be used on a range of materials and applications, and can be customised to fit a plant’s exact requirements.

“In 2016, a systems group approached Vortex at the IAOM Conference & Expo,” Millington.

“A flour mill in Texas, United States, has contacted the group to consider adding Vortex Loading Spouts to a loadout station. Engineers from Vortex and the systems group discussed the project throughout the week, continuing to collaborate when they returned to the office and found a solution.”

Two Vortex Loading Spouts were installed in the mill to receive material via air slide conveyors, with the remaining six spouts mounted below two bulk bins with fluidised bin dischargers.

This allowed the plant to capture any dusts generated during the loading process at a central aspiration system, significantly reducing emissions and material wastage.

The spouts have also been used in applications with highly abrasive materials. A water heater manufacturer, based in the US, needed to reduce the amount of dust being emitted to meet new health and safety standards for crystalline silica exposure.

The manufacturing process involved discharging glass frit blends directly from bulk bag unloaders into ball mills. As free-falling materials entered the ball mills, impact forces created a lot of uncontrolled dusts. The ball mills are used to grind the glass frit before mixing it with water to create a paste-like substance. The mixture is applied to the interior of water heaters before they are dried and furnace-fired, to create a corrosion-resistant lining.

Two Vortex Loading Spouts were installed to interface the discharge of each bulk bag unloader with the loading port of each ball mill. Above, bulk bags of glass frit blend are placed in the bulk bag unloaders before the spouts are extended into the loading port of each ball mill.

Once the ball mills are filled, the spouts are retracted, and each ball mill’s loading port is closed.

Often, loading spout systems will also be used in conjunction with slide gates, diverter valves and spin loaders that control the material flow during the loadout process. Used at the bottom of a silo or hopper to shut off material flow, slide gates are placed right above dust collecting filter systems, loading spouts and positioners.

Millington says Vortex offers a range of loading spout systems, gates and diverters for any number of loading processes.

“We can also custom engineer any telescopic loading spout system to meet your most demanding loadout application requirements, including corrosive or hazardous materials, long distances, low and high temperatures,” Millington says.

“Vortex fully assembles, factory tests and packages every loading spout system before shipping it to your facility to provide ease of installation and to ensure optimal performance once in use.”