Prairie DRY
In an industry first, West Fraser’s Alberta Plywood operation in Edmonton, AB, has installed a complete new jet dryer from Westmill Industries, boosting drying capacity by 20%.
By: Bill Tice
The temperature wasn’t the only thing heating up in the Alberta Capital city of Edmonton this past spring as Alberta Plywood cranked up the BTUs on a new six-deck veneer drying system. The new jet dryer from Aldergrove, BC-based Westmill Industries was started up for the first time in February, and was fully operational by the end of March.
With the new dryer in place at the plant, which is a division of West Fraser Mills, the facility has increased annual drying capacity by up to 20%.
“We were pretty much at full drying capacity and that was with two very inefficient dryers,” explains Dan Lewis, the plant manager.
Lewis notes that they wanted to run the lay-up line “24/7,” and with the drying capacity they had, that was just not possible all of the time.
“We were running 18 to 19 eight-hour shifts per week,” he adds. “Now we are able to run 20 to 21 eighthour shifts. This is also an old plant and floor space was tight, so we wanted to open things up for better air quality and improved health and safety, and by putting the new dryer in a brand new building, we were able to accomplish that.”
The new building Lewis refers to is a 60,000 square foot pre-engineered structure supplied by Heartland Steel in Prince George, BC, and manufactured by Brytex Building Systems in Edmonton. With its 120-ft long heating section and 18-ft long cooling section, the dryer itself takes up most of the one third of the floor area that is currently being used in the new structure. The infeed includes a three-head vacuum feeder, a load accumulator, a pinch wheel feeder with hydraulically controlled tipple, and an infeed rollcase with overlap gates. The veneer dryer consists of: a green-end vapour evacuation section to prevent dryer vapour from escaping into the plant and allowing the dryer to run with more humidity, resulting in flatter veneers and improved veneer quality; 20 heated sections with each one being six feet long; a three-foot dead air section; and three cooler sections. In addition, the dryer is equipped with a Maxon APX gas burner system capable of providing 60,000 BTU and features a Fireye flame safety system.
The dryer outfeed system features a six-deck sequential unloader and a split level outfeed with a two-level multibelt apron, a corner transfer conveyor, merge belt conveyors and a landing table.
The dryer control system includes automatic temperature, humidity and damper control, a PLC-based plug-up detection system, and a PLC cabinet complete with an Allen Bradley ControlLogix L61 processor and Allen Bradley VersaView 1500 computer screens for simple graphical operator interface for the fans, dampers, dryer drive and temperature. Other information displayed on the screens includes alarm information, trending, and other production statistics such as downtime per shift, the number of veneer sheets fed per minute or hour, and menus for product-based production control for dryer temperature, damper position and fan speed settings.
Starting fresh
Westmill is recognized in the industry for its dryer rebuilding capability, but the Alberta Plywood dryer is the first of its kind and the largest dryer the company has built. In the design of the new dryer, Westmill engineers implemented a Door Seal System 1-2-3, which is a replacement door seam system introduced to the market in the fall of 2004. It allows for changes of a door’s seal in minutes rather than hours. Patented articulating door hardware was also specified, which allows for adjustment of the door closure pressure from outside of the dryer, even if the dryer is running. They also used OILES dryer bearings, which are proprietary new dryer bearings made from alloy metal with graphite lubrication spheres. With the bearings being impregnated with Teflon, graphite and copper, they are designed for a longer life than standard bearings.
For the dryer conveyor system, the Westmill design called for common parts that are interchangeable with other veneer dryers that are in common use. This ability to interchange parts allows Alberta Plywood to minimize parts inventory on site, as many of the parts they will stock are interchangeable between the Westmill dryer and the on-site dryers from other manufacturers, including models from Coe and Moore (USNR).
All of the equipment following the outfeed came from dryer number 4 in the older area of the mill. Most of this equipment was installed four years ago as part of another significant upgrade and mill flow reorganization.
“Everything up to the 90-degree turn in the line is new equipment, and everything from that point on came from our dryer number 4 in the older part of the mill,” explains project manager Brian Northup, who was seconded from West Fraser’s Pacific Inland Resources sawmill in Smithers, BC for the Alberta Plywood project. “The equipment that came from dryer number 4 includes the scanning system and the stacker, and they were both new when we did a major upgrade to the plant in 2002,” he adds.
Dryer number 4 now only runs random, and the veneer is graded and pulled manually. In addition to moving the Raute Mecano scanning equipment and the Raute stacker, Northup says they had to move one console and do some basic maintenance.
“Much of the maintenance work needed to be done anyway,” he says. “It was things like changing belts and wear strips, and we also upgraded the Mecano VGA G2 scanner with new software and new lights.”
As part of their proposal for the new dryer, Westmill included time for consulting with West Fraser on the moving of the nine-bin stacker and grading line and making modifications to the existing conveyor system. They also included new controls and a VersaView 1500 touch screen for the relocated stacker.
Because the new dryer was being constructed in a brand new building, downtime at the plant was minimal.
“We pre-planned everything and had most of the wiring ready to go on the new dryer, so when we were ready, we just shutdown dryer number 4 long enough to disconnect.
