Safety and Prevention at the Heart of Powder and Bulk Materials Transfer

Explosion prevention and suppression in powder and bulk transfer is a top-of-mind concern for regulators and inspectors. Fortunately, suppliers with broad material-handling expertise help deal with it.

By Kevin T. Higgins, Managing Editor

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Doan Pendleton

Doan Pendleton demonstrates the hydraulic jack that lifts Vac-U-Max’s “swing-way” filter top. The innovation is designed to speed the cleaning process.

Mergers and acquisitions are more than fodder for the business pages. They also can signal broader vendor competence in helping food manufacturers address process challenges and opportunities.

Proof of that was evident at the May International Powder & Bulk Solids Conference & Exhibition in Rosemont, Ill. Many manufacturers want to pare down the number of vendors they work with and have a go-to supplier for critical systems, and exhibitors were eager to demonstrate how their evolving competence profile can deliver single source, integrated solutions.

A recent example involves Schenck AccuRate, a Whitewater, Wis., fabricator of feeders and weighing equipment for dry materials in process industries, and Kansas City-based Mac Process, a supplier of pneumatic conveying and air filtration systems. The two firms completed their merger in January, and the new entity, Schenck Process LLC, demonstrated the synergy by showcasing a continuous dense-phase conveying system that leverages Schenck’s weigh-belt expertise.

Because it runs continuously, no surge capacity is needed. Blowers operate at lower velocity, boosting energy efficiency, according to Mark Nagely, industry manager-food. The system handles both fine particles and coarse materials, gently moving them at a rate of about 800 ft. per min.

Three months before Schenck Process was established, pneumatic conveying and gravimetric feeder specialist K-Tron became Coperion K-Tron. The newly minted organization was in Rosemont to showcase its expanded capabilities. For food processors, the most meaningful capability is tighter integration of extruders and loss-in-weight feeders, with sanitary design and quick-release connections incorporated into all components.

The merger of Taylor Products and Smoot to create Magnum Systems occurred a dozen years ago, but R&D is ratcheting up to meet emerging process needs. The Kansas City-based organization displayed a pneumatic conveying system that combines elements of dilute, dense and semi-dense phase systems that is particularly suited to fine powders. Called the Ecophase, the system throttles back on the blower but runs it continuously. The result is a horsepower reduction that cuts energy consumption as much as 30 percent.

Coperion K Tron Stuart Wilson

Coperion K-Tron’s Stuart Wilson exposes the interior of the firm’s new sanitary filter receiver. The side-entry access door supports the filter media without horizontal supports and other potential harborage points, speeding the cleaning process between recipe changes.

One of the biggest suppliers of powder and bulk handling equipment is Flexicon Corp. The Bethlehem, Pa., firm isn’t active in the merger area, but it is expanding its process options.

​Dilute phase positive pressure and vacuum conveyors long have been part of Flexicon’s product portfolio, and the firm recently added tubular cable conveyors for fragile and brittle products susceptible to damage in dense phase conveying. Flexible screw conveyors have been a part of Flexicon’s product line since the founding of the company in 1974, notes David Boger vice president of global business development and marketing. He added that they are economical to operate, easy to clean and are well-suited to a wide range of materials.​

Pressure release

Ten days before the show kicked off, a dust explosion in a bag room at Georgia-Pacific’s Corrigan, Texas, plywood mill created a fire that critically injured three workers. It was a painful reminder of the 2008 dust explosions at Imperial Sugar’s Port Wentworth, Ga., mill that killed 14 and injured scores. The 2008 disaster triggered an overhaul of explosion control regulations, and a number of specialists in fire suppression and explosion protection for pneumatic conveying systems were on hand at the Powder & Bulk Solids show to promote their solutions.

In case anyone was unaware of the potential dangers when handling small particles under pressure, Johannes Lotterman, head-project control at Rembe Inc., Charlotte, N.C., demonstrated the danger twice a day with controlled explosions. Lotterman placed a few tablespoons of combustible dust in a 3-liter container, pressurized it to 2 bar (about 29 psi), then delivered an ignition spark to create an explosion and flameball through a pressure-relief vent. He then repeated the demonstration with a flame-arresting device for “flameless venting” inside a facility.

NFPA 654, the National Fire Protection Assn.’s standard for the prevention of fire and dust explosions while handling combustible particulate solids, was created after the sugar mill disaster and underwent its second revision last year. The frequent changes have contributed to manufacturer confusion about proper venting and explosion protection in their facilities.

The vast majority of food powders meet the standard’s combustion threshold, according to Flexicon’s Boger, but combustibility levels vary, and the standard is somewhat vague about necessary safeguards. “Depending on the equipment we’re trying to protect, it could double the cost of a project,” he says.

The added cost is particularly challenging for small food companies, many of which operate without any suppression or control systems, suggests Helen Sztarkman, Rembe’s sales manager. The introduction of new venting and suppression technologies also has left regulators playing catch-up. Four OSHA inspectors visited her booth, she said, to learn about remediation options as they prepare to enforce higher standards.

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