Miller sticks to adhesive conveyor

Sometimes resolving a sticky situation requires a measured and delicate approach. For Miller Brewing Co.’s Fort Worth , TX bottling facility, a conveying system designed in-house with ALL-CON World Systems, Inc. at its sister facility in Eden, NC gently and efficiently alleviated difficulties with hot-melt glue chip (also known as BB’s or chicklets) handling on their bottled beer carton and tray sealing lines.

After being put through its paces for five years in Miller’s Eden plant, the ALL-CON CLEANFEED® Automatic Glue Feed System was installed in Fort Worth in September 2001. According to retired Miller employee Jim Good, who collaborated extensively with ALL-CON to develop the system in 1996, the conveyor provides steady thermoplastic adhesive feeding to glue melting units for increased machine uptime with more consistent-quality melting and sealing than with hand loading. In addition, he says CLEANFEED’s filtration system greatly reduces the cost associate with clogged adhesive nozzles.

Before a CLEANFEED system was installed, Mike Chamberlain, technical services area manager – electrical, says that operators in the Fort Worth plant were required to heft 40 lb. cartons of adhesive chips to the melter, where they would manually scoop them into the unit as needed. “One of the drawbacks of this method is that you get a stratifying effect,” explains Good. That is chips at the bottom of the tank may measure 350 degrees F, but “layers” above would be cooler and would change the temperature of the glue mixture. ”If you do not maintain a high enough or consistent enough temperature, then all of the glue will not penetrate the wax coating on the cartons,” he adds.

Additionally, operators, who were often required to simultaneously attend to other tasks such as loading the carton magazines, would sometimes unintentionally allow glue to run low in the melter. This resulted in adhesive charring, which caused clogged applicator nozzles and equipment downtime. Charring also occurred as the dust and powder that covered the glue chips in their original packaging was inadvertently loaded into the melter.

With  CLEANFEED a radio frequency probe positioned in 1 ½ inches from the bottom of the melting tank sends a signal to a controller when the tanks needs to be refilled and prevents glue from running low. The system then activates a vacuum line that transports chips from a Gaylord to vacuum chamber assembly before being dispensed into the melting unit. To prevent foreign particles such as fines (particulates measuring 10 microns or less) and powders from entering the melter and clogging adhesive applicator nozzles, CLEANFEED filters the thermoplastic glue at various points in the conveying process.

In the case of the Eden installation, Good says that CLEANFEED brought about a “radical change” in the number of glue nozzles needing replacement on a regular basis when filters were cleaned or changed daily. Before ALL-CON’s CLEANFEED system, he notes, the plant could go through 50 – 80 nozzles a month in dry weather, and 100 – 120 during periods of high humidity. With the new system, that number dropped to a mere 12 nozzle replacements per month – a sizable cost savings. While the Forth Worth facility has not seen a dramatic change in nozzle use, Chamberlain notes that charring and downtime have been considerable reduced.

Another unique feature of the CLEANFEED system, relates Good, is its ability to self-clean. At the end of each cycle, the system is automatically purged clean to assure there is no material build-up in the conveying lines. “…other systems will leave chips laying in the conveying tube, and that’s not a good thing in high humidity.”

In addition, CLEANFEED restricts moisture from entering conveying lines due to heat transfer from the melter. Thus, glue chips remain dry and do not bond together before changing to a molten state upon entering the melter.

Miller Brewing Co., now has ALL-CON CLEANFEED® Automatic Glue Feed Systems running on 10 of its packaging lines, including six in Eden , two at its Trenton , OH plant, one in a facility in Albany , GA and its Fort Worth line. Apparently, when Miller finds something that works well, they stick to it!    *US Patent # 6,095,803