Tubular dragcableconveyorshelpcompanyturn greencoffee beansinto smoothblends

A coffee roaster specifiestubular drag cableconveyors for a new facility’sproduction process toreduce operating costs andimprove productionefficiency.

Apffels Fine Coffees, Santa FeSprings, Calif., produces awide r ange o f cus tom-

blended regular and flavored whole-bean and ground coffees and othercoffee ingredients for food stores, pri-vate labelers, and food-service estab-lishments. The company importshand-picked green coffee beans andcustom-blends and roasts them tomake the whole-bean and ground cof-fee products that are packaged in 1-ounce to 5-pound valve bags fordistribution. In early 2004, the com-pany worked with an engineeringfirm to design and build a new ad-vanced computer-aided roasting facil-

ity for small-batch and high-volumeproduction runs. When planning thefacility, the company needed to installa conveying system that would effi-ciently and gently move the coffeebeans and ground coffee through theproduction process without diminish-ing product quality.

Finding better conveyorsIn the past, the company used bucketelevators, augers, and pneumatic pres-sure conveying systems to move thebeans and ground coffee through theblending, roasting, grinding, flavoring,and packaging processes. However,

The freshly roasted coffee beans discharge from the roasters into a hop-per that directs them to the conveying system that gently moves them tothe holding silos.

New installation

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these conveyors were maintenance-and labor-intensive and required ex-cessive production downtime to cleanbetween product runs to prevent cross-contamination. “This kept our opera-tion costs high and decreased ourproduction efficiency,” says DarrylBlunk, Apffels president. “The con-veyors also broke the roasted coffeebeans and declassified the coffeegrounds because of the way theyworked. This was a problem becausewe want unbroken beans and a consis-tent grind distribution at the end whenwe package the final product.”

When the company decided to buildthe new facility, it worked closely

with Nohbell Corp., Bellevue, Wash.,an engineering firm that specializes indesigning, developing, and imple-menting supply-chain operations forcoffee, wine, and food processors.During the planning stage, the engi-neering firm recommended that thecompany use enclosed tubular dragcable conveyors to move the beansand ground coffee through the pro-duction process. Based on the engi-neering firm’s experience in thecoffee industry, these slow-running,dust-free conveyors would carefullyconvey the friable roasted beans andground coffee without breaking thebeans or stratifying the grounds. Andbecause of how the conveyors move

The roasted beans discharge from the holding silos (right) into a convey-ing system that moves them vertically and then horizontally above thetwo grinders (bottom left).

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material through the enclosed tubes,they would also reduce maintenanceand cleaning requirements and im-prove production efficiency and prod-uct quality.

The company sent samples to a rec-ommended conveyor supplier fortesting. The supplier, Cablevey Con-veyors, Oskaloosa, Iowa, manufac-tures custom-designed conveyingsystems for the food processing, agri-culture, wood, and other bulk solidsindustries. The tests proved success-ful, and the company’s engineersworked with the supplier’s engineer-ing team to custom-design eight con-veying systems for the new facility.

The tubular drag cable conveyorsIn late 2004, the supplier’s techni-cians installed eight Model 4000 Se-ries tubular drag cable conveyors,some of which have multiple dis-charges, in the company’s new roast-ing facility. Each conveyor consists oftwo 4-inch-diameter enclosed tubesections (an infeed and a return tube)with a turnaround section at one endand a variable-speed 5-horsepowerdrive-and-sprocket assembly at theother. The turnaround section con-nects the infeed and return tubes at theinfeed end and includes an automaticcable-tensioning device. The drive-and-sprocket assembly connects thetubes at the discharge end, forming acontinuous circuit. If necessary, astrategically placed mechanical cor-ner in the conveying circuit redirectsmaterial at a horizontal or verticalright angle. The conveyor is con-structed of stainless steel, making itsuitable for food-grade applications.

A continuous flexible stainless steelcable is installed inside the enclosedtubes, and solid, food-grade, ultra-high-molecular-weight polyethylene(UHMW-PE) circular discs aremounted on the cable at regular inter-vals. The discs are shaped to ease ma-t e r i a l movemen t and r educedegradation. Since the discs arenearly the same diameter as the tubes,their narrow clearance with the tubewalls ensures that the material stays

between them during conveying andminimizes residue on the tube walls.To minimize downtime betweenproduct runs, a food-grade clean-outdisc mounted on the cable keeps thetubes clean, and a continuously oper-ating air-knife at the outlets blows airacross the discs when they pass to dis-lodge any material from them.

The production process equipmentand conveying systems are fully auto-mated and integrated with a centralcontroller, allowing remote controland monitoring of the entire processfrom one location. Using the con-troller interface, an operator creates arecipe for a custom-blended coffeeproduct and pushes the start button.The controller then automaticallyopens and closes the necessary valvesand conveying system discharges tomove the beans and ground coffeethrough the production process, frombag-break station to packager.

To make a custom-blended coffeeproduct, an operator empties the spec-ified bags of green coffee beans into abag-break station’s hopper. The beansdischarge from the hopper into asmall bucket elevator that moves thebeans up and over to a hopper thatconnects with sizing and screeningequipment. This equipment removesoff-size beans and any foreign materi-als, such as sticks or rocks. The beansare weighed and then discharged intothe first tubular drag cable conveyingsystem, which moves them to one ofsix silos. To blend the beans, the con-troller activates the appropriate silodischarge valves to gravity-dischargethe correct combination of beans intoa large hopper, which discharges tothe second conveying system, whichmoves the blend to one of two roastersfor roasting via the system’s two dis-charges.

The roasted beans discharge into thethird conveying system, which movesthem to one of 12 holding silos. Thecontroller activates the appropriateholding silo discharge valves to grav-ity-discharge the beans into the fourthconveying system, which can movethe beans to one of three locations via

the system’s four discharges: the fla-voring room, one of two grinders, orthe packaging room conveying sys-tem. If the beans are directed to agrinder, the ground coffee dischargesinto the fifth conveying system, whichcan move it to either one of four de-gassing silos or to the packagingroom conveying system via the sys-tem’s two discharges. The sixth con-veying system moves the groundcoffee from the degassing silos to ei-ther the flavoring room or the packag-ing room conveying system via thesystem’s two discharges.

The packaging room conveying sys-tem is the seventh system, and itmoves both regular and flavored cof-fee beans and ground coffee to one offour packaging stations via the sys-tem’s four discharges. The companyuses the eighth conveying system toput rework back into the productionprocess. By way of this system’s twodischarges, material can be moved toeither the third conveying system thatconnects to the holding silos or the

The central controller can activatethe conveying system’s first dis-charge (right) to direct the beans tothe flavoring room, the second orthird discharge to direct them toone of the grinders, or a fourth dis-charge to direct them to the pack-aging room conveying system.

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fourth conveying system that con-nects with the grinders, flavoringroom, and packaging room conveyingsystem.

According to Guillermo Contreras,Apffels production manager, thecompany operates the conveying sys-tems at 85 percent of their maximum100-foot-per-minute rate and canmove 3,000 pounds of ground coffeefrom a grinder to the degassing silosin about 45 minutes. Overall, the eightconveying systems have a total of1,970 feet of tubing. To ensure safetyduring operation, if a cable is ten-sioned too quickly or breaks or a turn-around-section cover is opened, thesystem automatically shuts down andsounds an alarm to alert the operators.

Improving the production processSince installing the tubular drag cableconveyors in the new roasting facility,the clean-out time between productruns and the maintenance and laborrequirements have significantly de-creased. “The clean-out discs insidethe tubes take out just about every-thing, leaving little to no residue onthe tube walls, so it only takes aboutfifteen to twenty minutes betweenproducts,” says Contreras. “We’vebeen using them for more than sevenyears, and I haven’t had to do much tothem, other than maintain the gearboxes, turn-arounds, and drives. Andif a cable or disc ever breaks, we justhave to a splice in a new cable sectionor mount a new disc on the cable andwe’re running again. It only takesabout an hour, depending on wherethe break occurs, and I keep plenty ofspare parts onsite. We once had to re-place a full cable and the system wasonly down for about half a day, whichis much less time than it would take tofix the bucket elevators.”

The conveying systems have also im-proved the company’s production ef-ficiency and product quality. “Theconveyors maintain the grind consis-tency as they move the ground coffeethrough the process to packaging,”says Blunk. “We’ve also seen a signif-icant decrease in bean breakage be-

cause the conveyors move the beansso gently. They’ve really helped usimprove and maintain the quality ofour whole-bean and ground-coffeeproducts.”

According the Blunk, if the companyexpands the current productionprocess or adds a new one, the sup-plier will be the first one he calls forconveyors. “Their conveying systemshave enabled us to consistently pro-duce top-quality products and easilymaintain a dust-free, sanitary opera-tion for more than seven years now,which is critical from a food-safetystandpoint,” he says. “They’ve been agood partner and have always beenresponsive. We definitely challengedthem with this installation, but therewere things we discovered during theinstallation process that helped themimprove and enhance their conveyors,so I think it’s been a win-win situationfor both of us.” PBE

Note: Find more information on thistopic in articles listed under “Mechan-ical conveying” in Powder and BulkEngineering’s Article Index in the De-cember 2012 issue and at PBE’s web-site, www.powderbulk.com, and inbooks available through the website inthe PBEBookstore. You can also pur-chase copies of past PBE articles atwww.powderbulk.com.

Cablevey Conveyors, Oskaloosa, IA641-673-8451www.cablevey.com

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