Eight hours each day, five days/week, for 12 years: that’s the kind of equipment dependability that a market-leading company demands in order to stay in the lead. And that’s exactly what the bagging line at Union Specialties Inc. has been providing since it was installed in May 2001 by Premier Tech Chronos, headquartered in Rivière-du-Loup, QC, Canada.
Union Specialties Inc., headquartered in Newburyport, MA, is a major player in the global leather market. The company produces dispersions and specialty products for the leather and coatings industry worldwide, with production facilities in more than 49 countries.
Used to make basecoats and topcoats for leather tanning applications, Union Specialties’ dispersion products contribute to films that range from hard to flexible and confer sturdiness and longevity to end products such as leather footwear, garments, and furniture.
The bagging line installed at Union Specialties in 2001 comprises two Stonepak model 801 impeller-type valve bag fillers with DM weight controllers, a model 858 empty bag conveyor, a robotic palletizer model S430I Fanuc robot, a model 390 empty pallet dispenser, a model 405 upright slipsheet dispenser, a model LRT-4000 chain-driven roller conveyor, and a model 880 gravity-powered roller full-pallet accumulation conveyor (Stonepak is Premier Tech Chronos’ product line of valve bag fillers and related equipment).
When the line is activated via operator/touch-screen interface, the model 390 empty pallet dispenser places an empty pallet onto the LRT-4000 transfer conveyor, which advances the pallet to the model S430I Fanuc robot. The robot picks up a slipsheet from the model 405 upright slipsheet dispenser, places the slipsheet on the pallet, and picks up an empty bag from the model 858 empty bag conveyor.
The robot first places the bag on one, then the other, 801 valve bagger. As soon as a bag is full, the robot removes it from the bagger and places it on the pallet, and puts another bag on the filler. Once the pallet is full, the transfer conveyor advances the pallet out of the robot work cell and through the light curtain, at which point the pallet can be removed from the conveyor via forklift.
All those filled pallets represent an “increase [in] output of 100 percent,” according to plant manager Tom Marshall. That’s due to the robot and the two 801 valve baggers, which jointly produce 240 bags per hour. These impeller-type fillers are well-suited to handle the protein-containing compounds manufactured at Union Specialties, as well as other fine powders sized 200 mesh or finer, including cement, coal, clay, limestone, and other minerals, talc, wood flour, and other wood products.
Part of what makes the model 801 a sensible choice for bagging fine powders is that its two horizontal side screw conveyors minimize the introduction of air as they feed material into the bagger, which maximizes filling speed. Less air introduced into the material also means smaller bag sizes, which leads to easier handling for the end user (bags produced on Union Specialties’ line are 25-kilo polylined paper bags). This type of bagger also decreases fugitive dust, which helps to maximize output by decreasing material loss, as well as lowering the risk of explosion and breathing-related employee health problems.
In addition, the Stonepak model 801 bagger minimizes dust because of its fully enclosed material flowpath between the supply bin and the bag. This material protection, plus the fact that the impeller-style model 801 bagger transfers material with minimal aeration, minimizes dust production compared with other types of baggers. Any dust that might be produced during filling is reclaimed by the dust collection port located between the filling spout and the bag.
There is an additional safeguard against material loss to dust. “The bags are internal valve bags, so they are sealed by the internal flap,” says Premier Tech Chronos sales manager Gary Ritter. This avoids potential material loss that could occur at a separate bag-sealing station.
One challenge that can’t be avoided is ratholing, notes Marshall. This is a typical problem encountered in handling small, sticky powders, such as those that contain protein, and can obstruct flow and cause material segregation. It occurs when powder in the center of a hopper flows faster than powder near the hopper walls. Sometimes, powder near the walls may not flow at all until the level of material in the hopper has decreased down to the converging level of the hopper.
To avoid the obstructed flow and material segregation that ratholing produces, Union Specialties uses aerators installed in the supply hoppers. Premier Tech Chronos provides aeration “units manufactured by sub-vendors when they are needed,” explains Ritter, adding that aerators can be retrofitted to an existing line.
This support of all aspects of an equipment line includes providing technical support for equipment even after it has evolved into a more advanced model and is no longer manufactured. Such is the case with the model 801 bagger’s “DM model weight controllers [which are] obsolete, although we still support them through our parts and service department,” says Ritter.
“Our current control models are our NXT, and Intelligent Packer Controller,” Ritter continues. “These controllers are user friendly and have ‘recipe’ storage capability. Each recipe is related to a different material that is bagged and contains the set of control parameters which optimize [bagger] operation for that material. This results in the greatest production rate possible while achieving bag weights that are within the acceptable tolerance limits. These controls provide more information to the operator to help him or her optimize the functioning of the baggers.”
As a result of installing the bagging line, Union Specialties has been able to “decrease dust, minimize labor [and employee] back injury, and increase output by 100 percent,” according to Marshall, who says maintenance of the bagging line is minimal. Routine upkeep requires “employees 20 minutes a day, with no [help needed from] Premier Tech,” with annual maintenance of the line averaging $200. Apart from a minor retooling of the robot’s end-of-arm operation shortly after installation in 2001, the robot — the first one ever installed by Premier Tech Chronos — has functioned flawlessly. According to Union Specialties’ Web site, this “bagging system … has dramatically increased the modern manufacturing facility’s capacity.”
For more information on Premier Tech Chronos, call 418-868-8324 or visit www.ptchronos.com.
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