Coffee Conveyors Keep it Clean

Ports are the ideal location to clean up green coffee arriving from origin.

“Port NOLA offers value-added services for imported coffee that include capabilities to weigh, sort, grade, roast, and package coffee,” according to Donnell Jackson, media relations manager at the Port of New Orleans.

Warehouses at port facilities dedicated to receiving coffee in large quantities can efficiently destone, remove metal and plastic using sizing and screening equipment, and with specialty grades, optically sort coffee for roasters with limited space and equipment.

Moving huge quantities of green coffee arriving in bulk and moving between silos is challenging, explains Karl Seidel, marketing director at Cablevey, a leading drag conveyor system.

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“Green coffee beans are more fragile than you might imagine, and can cause binding and breakage of the raw bean in the conveying process, if not engineered thoughtfully,” he says.

Facilities equipped with bucket elevators, augers and pneumatic pressure conveying systems are more likely to break green coffee, he said. “Bumping, battering, stress, or friction lead to breakage,” he explains. In specialty grades, the result is a loss in quality and wholesale price.

A typical installation consists of 4-inch diameter enclosed tube sections (infeed and return) with a turnaround section at one end and variable speed drive-and-sprocket with an automatic cable-tensioning device. The continuous circuit is constructed of stainless steel, suitable for food-grade applications. Coffee is gently conveyed by solid, food-grade, heavy-duty polyethylene mounted at regular intervals. A food grade cleanout disc is used to keep the tubes clean and a continuously operating air knife at the outlets blows debris off discs as they pass.

A recent installation enabled Nippon Coffee to transport approximately 600-800 kilos of green coffee per hour utilizing Cablevey technology, said Seidel.

Completely clean

There are five steps in making coffee pristine. Fines, dust, chaff, and other light material are removed using a negative aspiration system as green coffee proceeds through scalping screen (to remove larger objects) followed by sifting screens (to remove smaller objects. Green coffee is then exposed to bottom air to separate low-density product.

Destoners - Objects 2.5 times or greater density than green coffee (stones) are separated during this stage.

Sizer/Grader - Clients specify screen size to sort the coffee by bean width. Typically there are four screens in use, three of which are sizing good product with a fourth for waste.

Gravity table - Undesirable coffee beans of the correct size, but low density are less desirable. This device isolates low-density beans.

Color sorter - Optical sorters scanning for color intensity and tonality are used to discard coffee with color defects. Beans that are black (stinkers), deep blue, or dark brown and those showing undesired red, yellow, white, and various shades of green

Food safety concerns

Provisions of the Food Safety Modernization Act (FSMA), enacted in 2011 requiring stricter standards and practices in the way food is handled, transported, and processed, are now enforced following a five-year transition. The new law shifts the focus of food safety management to prevention.

Since FDA began inspecting importers for the new food safety mandates last year, the agency has issued more than 100 compliance-related citations. In 2017 FDA conducted about 300 foreign supplier verification program (FSVP) inspections. In 2018, when the new regulations expand to include all firms employing 500 and fewer employees, the agency said it will conduct several thousand FSVP inspections.

Safeguarding food requires vigilant inspection of tubular drag conveyor systems to prevent tainted product from making its way to the public, says Seidel. “Cablevey’s conveyor monitoring system cameras help handlers comply with FSMA regulations, he said.

Engineers at Cablevey developed a mini-HD inspection camera as a diagnostic tool used during the preventative maintenance cycle. The video cameras, mounted inside the tube, are self-contained with a removable micro SD card and LED lights. The video is formatted for use on any computer and the high-resolution images reveal build up, dents, improper alignment of pipes. Verifying the cleanliness of the tube’s interior ensures a high level of sanitation, he said.