How to achieve better HVAC and dust collection

In southern California, Mulligan Sales blends dry dairy and other food ingredients for makers of baked goods, snack foods, and confections. These powdered ingredients typically create high dust levels that tend to absorb moisture in the air, requiring cool, dry in-plant conditions.

In its powdered ingredients processing facility, Mulligan Sales required both substantial dust collection and constant air conditioning for temperature and humidity control. Running both systems simultaneously was not an option with the company’s existing dust collectors — an external baghouse unit with envelope-type ﬁlters and a manual shaker for ﬁlter cleaning.

The existing system vented outside, returning no air back into the mixing and batch-weighing areas. And, because the unit would have extracted conditioned air, as well, the air conditioning could only be run when the unit was off and the facility was not blending.

Additionally, the facility had limited power available for the dust collection equipment, so a bigger system alone was not the answer. Mulligan needed a solution to:

improve collection of high levels of dust while integrating with the facility’s environmental controls, saving costs and losses associated with external venting
provide vastly updated ﬁltering technology for improved performance and reduced maintenance
fit the solution to the limited available power.

Figure 1. The exhaust duct from the SFC downward flow dust collector is equipped with in-line silencer and safety filter.

A United Air Specialists (UAS) representative performed an assessment of Mulligan’s existing equipment, identiﬁed its key design inefﬁciencies and areas in need of dust collection, and considered the company’s potential need for additional processing equipment in the future.

The representative then arranged a tour of a successful UAS installation at a snack food maker’s facility. Impressed with its performance, Mulligan chose to work with UAS, which solved Mulligan’s temperature control needs with an external UAS SFC 12-3 downward ﬂow cartridge dust collector, customized with a C-3600 Cyclone pre-cleaner for each of the existing large mixer and batch-weighing areas (Figure 1). This achieved measurably more effective, efﬁcient dust collection than the previous baghouse unit. Unlike the former externally vented design, the new SFC system returned clean air into the facility. For further assurance the system featured an exterior safety ﬁlter, as well as a silencer to keep the noise level below OSHA guidelines (Figure 2).

Figure 2. The dust collector is integrated with the facility’s environmental controls to improve dust collection and save costs and losses associated with external venting, as well as provide improved filter performance and reduced maintenance.

As for system size, UAS tailored the design to meet Mulligan’s equipment and airﬂow goals, as well as the facility’s limited horsepower requirements.

Maintenance was also substantially reduced, since the SFC system required less frequent ﬁlter change-outs than the previous baghouse unit. This resulted from the SFC’s patented pulse-jet technology that pulses dust off ﬁlters. UAS designed this pulse-jet system to clean the full length of the cartridge ﬁlter for better, long-lasting performance while allowing the unit to clean the ﬁlters during operation. Further, the pulsing is delivered in regulated blasts of air, so fewer pulses are needed, which conserves costly compressed air.

“The facility went from having tremendous dust challenges to an 85% decrease,” says Byron Tobin, Mulligan Sales plant manager. With no external air discharge, the company also began saving thousands of dollars in state permitting fees, while reinforcing its good-neighbor commitment.

UAS’s solution also resolved the challenges of dust collection in conjunction with temperature and humidity control. “UAS worked with our vision all the way,” says Tobin, who also cited quality details that are yielding added value, including the system’s washable ﬁlter cartridges with a spare set for less downtime during change-outs, explosion relief vents for protection, powder-coated ﬁnish on the collectors for corrosion resistance, and three additional ﬂexible dust collection arms that allow reconﬁguration of the processing room equipment for other projects.

To accommodate Mulligan’s future needs, the new system can be expanded. The facility is initially optimizing 30-40% of the new system’s capacity, allowing for expansion or reconﬁguration to improve productivity at any time, says Tobin. “We knew we needed to step up,” he says. “The result is impressive, and we have future capability.”

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