By automating a former rice mill, coffeemaker Cadeco Industries increased its processing accuracy and reduced its labor requirements

When coffeemaker Cadeco Industries moved its operations to a former rice mill in the Houston area, it also engaged in something of an automation gambit -- and one that paid off.

By automating virtually all functions in the 200,000-sq.-ft. facility, the company was able to dramatically increase processing accuracy and quality assurance levels while reducing its labor force to just a handful of technicians and laborers.

The family-owned Cadeco sells coffee to major supermarket chains and specialty coffee companies, as well as food conglomerates that employ third-party brokers to buy for major brands. In some cases, Cadeco sells its own blend to a customer. In others, the company blends product to customer specifications. The new Houston facility can process up to 750 million pounds of coffee per year and provides a complete range of services that include cleaning, drying, blending, steaming, roasting, storing and shipping.

Cadeco president Carlos DeAldecoa says the size and location of the former rice mill helped make the property a perfect fit for his operations. The facility's 100 bulk storage silos and close proximity to the port of Houston were especially attractive, he noted.

Upon purchasing the facility, Cadeco had old electrical and mechanical equipment stripped out, leaving only the silos. "We considered leaving some functions hand-operated but finally decided to fully automate," deAldecoa said. "Our investment was higher at that point but our operating cost is [now] lower. We have a couple of process operators, some general laborers and a maintenance crew - that's all it takes to run the plant. One man can do what would take 30 to 40 people in a facility that wasn't automated."

The plant receives coffee by truck or railcar - either in bags of 120-155 pounds or in 20-ft. containers holding up to 46,000 pounds each. A hydraulic device tilts entire trucks to dump the containers into a receiving pit. The beans then flow via pneumatic lines through cleaning stages to remove any debris, fine dust, dirt, insects, twigs or rocks. Once air-cleaned, the product is then transferred to silos.

Total automation

The hub of Cadeco's automation system is the central control room equipped with a Modicon QUANTUM PLC supplied by Schneider Electric. Eight remote I/O drops control the various processing stages -- receiving, blending, cleaning, roasting, steaming, and other functions. The automation system tracks the rate at which each line is running and notes any anomalies that might indicate a maintenance problem. The plant's preventive maintenance program is based on parameters such as running time and numbers of cycles.

"Absolutely everything is controlled by the PLC," deAldecoa said. "All process parameters are pre-programmed. This includes receiving, silo selection, inventory control, blending, amperage on equipment, weighing systems and position indicators on valves and slidegates. With the system we put in, we can even load product into anything from a 50-pound box to a 50,000-pound truck or a 190,000-pound railcar, depending on what the customer needs."

The PLC also controls the pneumatic conveyance of coffee beans through 3- to 12-in. Schedule 40 pipe. Blowers as powerful as 150 horsepower transport 20,000-120,000 pounds of coffee beans per hour through the pneumatic lines. The PLC system also regulates pressure in pneumatic lines, motors, speeds and other parameters, and reports and logs process data in real time.

"Flow meters, level indicators - more than 50 scales throughout the plant - are constantly telling us the weight of each one of the processing lines and how much coffee is going through each line," deAldecoa said. "The process has so many alarms that if there is a problem the lines can automatically be stopped without waste. If a slide gate or a valve isn't opening all the way, or if a conveying line is running at a higher pressure than it's supposed to, or a position indicator isn't working - those situations will trigger an alarm in the system and hold that process until it is fixed by maintenance."

Schneider Electric also supplied five Square D Model 6 motor control centers (MCCs). The high-density MCCs incorporate circuit breakers to provide overload protection and include relays and motor starters to control various machinery motors from the control room. To better utilize floor space, the MCCs include Square D Compact 6 starter buckets to house the numerous starters with less than 50 horsepower. This configuration allows Cadeco to conserve space by mounting 12 starters in a single section of an MCC line-up.

"All relays from the MCCs tie back to the PLC," deAldecoa said. "Everything is looped together. The MCCs contribute to our lower operating costs because they help reduce energy consumption and increase productivity through precise motor control and accurate information about operating conditions."

Besides being important internally, the efficiency control aspect of the system adds to customer confidence. "Customer confidence comes from two things: being able to track their coffee at all times throughout the process and getting full reports of their inventory at any time," deAldecoa said. "We can even send customers the operation logs to show exactly how the process went. They can actually see how the coffee was blended and see the accuracy of the blends. We can track any bean at any time in the whole plant with our system."

Running at 50,000 pound per hour, the automated blending station can mix up to 33 different types of beans into a single blend, with accuracy within 0.1 percent of each batch. For every batch withdrawn from storage and processed, the computer generates a report citing exact percentages of coffee drawn from the silos in order to generate near perfect mass balances.

DeAldecoa said that Cadeco's full range of services is what initially gets the attention of prospective customers. The automated processing system from Schneider Electric, however, provides the hook that helps win them over. "We can give customers amazing repeatability on processing quality, " he said. "The accuracy and controls that we have are way above the industry standard. It's our biggest selling point."