An aluminum foundry and diecaster is a cooler and more pleasant place to work lately thanks to the adoption of some powerful dust-and odor-control equipment involving air cannons. LeClaire Manufacturing in Bettendorf, IA, is using BossTek® DustBoss® DB-30™ dust cannons to improve airflow, reduce indoor temperatures, and direct air toward internal ventilation systems. The result is not only a more temperate workplace but improved worker morale.
Open windows, wall fans, and large ceiling-mounted fans do little good without enough positive pressure within the building to push outside any significant amount of warm air. “The building was adequately designed for airflow, and we have several fans in place, but if the air outside is stagnant, the heat just hangs in the building and becomes very uncomfortable,” explained LeClaire owner and co-president Rob Zimmerman.
The plant —a supplier of aluminum castings for agricultural, RV, medical devices, valves/pumps, and other manufacturing sectors — has several melting furnaces in operation and 10 large windows approximately 8 feet (2.4 m) from the ground, and five more windows approximately 20 feet (6 m) from the ground. Heat generated by the production process rises toward a 38-ft (11.5 m) high, pitched ceiling with two high-velocity exhaust fans connected to vents.
Radiating heat spreads from each furnace and stretches throughout the shop. The lack of adequate circulation can cause the heat to stagnate, and during the summer humidity can weigh down the hot air, slowing its ascent or causing it to remain idle. As hot air rises and collects in the pitched roof, the two high-velocity exhaust fans struggle to keep up with hot-air volume, particularly in combination with the outdoor summer heat.
For hot air to exit the open windows and roof-mounted exhaust vents more efficiently, wind is essential. As wind passes the windows and vents, the low pressure outside draws out the heat. Without the higher pressure indoors, only the heat in direct proximity exits the windows, and exhaust fans need to work harder to pull heat out of the vents. Direct wind or high wind velocities can blow into open windows, creating circulation and cooling the air, but that’s a rare event in the Midwestern summer.
Along with exhaust fans, other methods have been used at ground level to promote air movement and offer relief. Periodically, fans were placed around the shop floor to aid air circulation. Also, portable air conditioners were placed at each of seven workstations to keep the immediate area cool for each worker. In a large area, like the molding department, none of these methods was quite adequate.
“We read an article about how a DustBoss had helped another diecasting operation with air circulation, so we decided to rent two DB-30 units for a summer,” Zimmerman said. “When they arrived, we were immediately impressed.”
Designed for dust suppression in large outdoor industrial settings using atomized mist nozzles, air cannon technology has been adapted for use in indoor manufacturing with high heat environments (including metalcasting operations) for effective air circulation.
The DB-30 has a standard 480V / 3-phase motor running an industrial 7.5 horsepower fan generating 9,200 CFM (260.50 CMM), positioned in the rear of a specially engineered, cone-shaped steel barrel. With the fan blades shielded by a heavy mesh guard, the unit draws air from the wide opening in the tail and forces it down the cone toward the narrower mouth in front. Compressing the air down the barrel increases velocity and directs the discharge.
Because the DustBoss is engineered to operate outside, large area coverage and mobility are critical to its effective, compact design. Mounted on a mobile carriage, the golf-cart sized unit weighs approximately 800 lbs (363 kg) and it can be repositioned easily wherever it is needed, using a forklift.
At LeClaire, the air cannons were positioned at an opposing wall, near the lower windows and pointing toward each other. Able to oscillate 359º and adjust vertically 0-50º, operators programmed the units to cover an arc of about 100º, drawing air inside from the low windows.
After a warmer than average summer, the LeClaire staff reported that the DustBoss units achieved their goal of cooling the area and promoting air circulation. Operators also appreciated the rugged construction and ease of use, being able to program the machine’s settings on the touch pad and walk away. “We could tell these machines were built to last and would require very little maintenance,” Zimmerman said.
Once a used DB-30 and a more-powerful DB-60 generating 30,000 CFM (849.50 CMM) became available, LeClaire’s managers took the opportunity to expand its installation.