Powder Processors See Advantages in Alternative to Traditional Baghouses

After enduring frequent filter plugging, extremely short filter life, and production slowdowns, Brunk Corp. welcomed the opportunity in January 2007 to beta test Donaldson Torit’s Torit PowerCore dust collector at its Bloomington, MN, operation. Brunk pulverizes PE plastic into powder for the rotational molding industry.

Torit PowerCore was commercially introduced to the market at the 2008 Powder Show in May, but powder processors such as Brunk and other companies that have wood, cement, concrete, grain, soda ash, and sand applications have been testing this complete departure from traditional baghouse filtration technology for more than a year. PowerCore technology has been proven in engine filtration for eight years.

Brunk has four attrition mills that are ducted to its Torit PowerCore collector. “I’m very impressed with Torit PowerCore. It’s a very small footprint for the amount of filter area you get in a unit,” said David Loeffler, plant manager at Brunk Corp. “I used to have a cartridge collector for my attrition mills, but the filters would plug after a couple weeks, reducing air volumes and decreasing productivity. I considered replacing it with a larger, more expensive baghouse collector, but then we tried Torit PowerCore and it gave us the right amount of filtration area in a much smaller unit.”

The filter packs are only 7 in. tall compared with a typical 8- to 12-ft-long filter bag. The filters are smaller and handle more air volume per filter pack, which allows the height of the collector to be reduced by up to 50%.

The technology is also available as a bin vent system, which is up to 70% smaller than traditional bin vent collectors. This size reduction allows the Torit PowerCore collector to be applied in a whole new point-of-use technique. For example, the smaller size of the collector allows it to sit right on top of a tripper hood in grain handling applications. Placing the bin vent collector on the tripper hood eliminates the need for maintenance-intensive zipper ducts and a large, energy-consuming central dust collector.

Because baghouse filter maintenance is troublesome, some plants avoid servicing or replacing filters altogether. Others shut down for days to change out large, heavy, dust-loaded filter bags. Typically, one PowerCore filter pack can replace nearly six 8-ft filter bags, reducing the time and labor cost of filter maintenance. Small, lightweight PowerCore filters have handles for easy serviceability. They are changed from the clean-air side of the collector and can be replaced without tools in minutes.

“We were replacing filters in our previous collector every few weeks,” said Loeffler. “We’re just now, after more than a year, replacing our trial Torit PowerCore collector with a production unit, and from the results I’ve seen so far, I don’t expect to replace my filters for a long time.”

Long Filter Life, Low Energy

Anchor Block Co.’s Shakopee, MN, plant has similar accolades for Torit PowerCore after it beta tested a trial collector last year and then installed a full-scale production unit in March. Anchor Block operates three concrete manufacturing plants in Minnesota, where it produces standard concrete block, decorative masonry units, landscape retaining walls, and paving stones for distribution in Minnesota, Iowa, South Dakota, North Dakota, Wisconsin, and Nebraska.

The full-scale production Torit PowerCore collector installed at Anchor Block is ducted to a 5000-lb concrete mixer, which mixes very fine and abrasive sand, fly ash, aggregates, and cement.

“The filters have worked really well since the collector was installed,” said Jay Battenberg, safety director at Anchor Block. “Every time I go by the collector, the pressure gauge is hovering at the 1-in. mark. Our other collectors—baghouse and cartridge—never run that low.”

In the cement industry, a dust collector still running without filter plugging at a very low pressure drop for more than three months is a rarity, says Battenberg. When the time comes to change the filters, he expects the process to be easy.

“It looks like it’s going to be really easy to change the filters—even easier than a cartridge collector,” notes Battenberg. “There are a couple of handles, and the filters just sit in the collector. It almost looks like an air filter in a car.”

How the Technology Works

Torit PowerCore’s similarity to engine filters is no coincidence. It is new technology for the industrial processing market, but Donaldson’s PowerCore filters with Ultra-Web technology have long been a mainstay in the engine market, providing high filtration efficiency in high-performance vehicles and in construction, agricultural, and medium- to heavy-duty transportation applications.

At the heart of the collectors are PowerCore Filter Pacs, which combine proven and patented Ultra-Web technology with a fluted-media packing design. Unlike traditional 16-oz polyester filter bags, these media are configured in fluted channels that are alternately sealed, allowing air to enter through an open flute on the dirty side of the filter pack and forcing the air to pass through the media to exit out an adjacent flute on the clean side of the pack. Fluted layering lends a tight, rugged structure to the filter. While traditional filter bags move when they are pulse cleaned or shaken, accelerating bag fatigue and wear, these rugged packs are stationary, prolonging filter life.

To further extend filter life, an Ultra-Web media layer in the filter pack flutes traps dust—even submicron dust particles—on the media surface, making dust easy to pulse off and promoting better filter cleaning. Ultra-Web’s surface-loading properties prevent the depth loading of dust that commonly occurs with traditional filter bags, allowing the packs to last longer, maintain a lower operating pressure drop over a longer period of time, and use less energy. Perhaps even more dramatic is the filter packs’ efficiency. Flat-sheet testing by independent labs shows that the filter packs provide up to 78% fewer emissions than polyester bags, which translates into cleaner air in the plant and greater product recovery.

PowerCore Filter Pacs work in tandem with the Torit PowerCore collector to provide longer filter life, cleaner plant air, and lower energy use. Optimized with a direct-flow inlet to manage airflow patterns and velocities below the filters, the filter packs’ air management technique keeps the bottom of the packs clean, promotes dust particle drop-out, prevents filter abrasion, and eliminates hopper sweeping and dust reentrainment.

For more information, contact Donaldson Torit, Donaldson Company, Inc., at 800-365-1331, [email protected], or www.donaldsontorit.com.