Mill Increases Efficiency By Avoiding Nasty Metal Contamination

Wire woes were causing breakdowns and excessive maintenance at a busy Northwest paper company. Equipment was needed that would remove wire remnants before they plugged up the refiner plates. The solution has proven to be both effective and economical.

Grays Harbor Paper, L.P., located in Hoquiam, WA, produces 450 tons of uncoated printing and writing paper daily. To make all that paper, the company starts with purchased market pulp, which it then re-pulps and ultimately turns into paper. The market pulp is usually delivered to the facility baled in wire. When these bundles arrive at Gray Harbor Paper, it marks the beginning of both another papermaking process and another battle against metal contamination.

Pieces of bailing wire were wreaking havoc on the machinery at Grays Harbor Paper. Wire remnants were constantly plugging up the refiner plates, which resulted in breakdowns, loss of production time, and excessive maintenance costs. The company began to recognize that dealing with the wire retroactively was not the best way. It needed equipment that would remove the wire before it made its way to the refiner. As a result, it set out to find a solution that would be both effective and economical.

Grays Harbor Paper management team began meeting with several manufacturers of magnetic equipment. Initially, the company was interested in buying an electromagnet, a device in which magnetism is produced by an electric current. After obtaining a number of quotes for electromagnets and analyzing long-term costs, Grays Harbor personnel realized electromagnets were not the answer they were looking for. "The continuous expense of electricity made them an unappealing option," said Vince Riso, paper production manager.

One of the companies they were working with, Eriez Magnetics, based in Erie, PA, suggested that the paper manufacturer think about installing permanent magnetic traps. Magnetic traps have a constant, powerful magnetic circuit that is designed to attract and hold iron contamination — with no moving parts.

Eriez personnel were confident that their recently redesigned Model T Trap would satisfy the company's needs. To show their product in action, they referred Grays Harbor Paper to a similar company in the area that was using the Model T Traps. "We were actually able to go out to the facility and see the T Trap in action. The operators even took it apart and demonstrated how easily and quickly it can be cleaned. We were certainly impressed," said Riso.

Model T Traps feature a drop-bolt design that allows for quick access to the magnet, thereby speeding the cleaning process. "The ease of opening was a big issue for us. We knew that these things were going to have to be opened up and cleaned pretty much on a daily basis," said Riso. "Some of the other companies' traps we looked at were not nearly as conducive to cleaning."

Grays Harbor Paper was also convinced that the Model T Trap would stand up effectively to the mill's corrosive conditions. With rugged welded pipe and reinforced construction, the traps can withstand working pressures up to 75 psi (5.27 kg/cm²). Plus, customers have the option of upgrading the trap bodies from standard mild steel to 304 or 316 stainless steel for even harsher environments. "It had all of the features we were looking for and the price was right. This made the decision to purchase the Model T Trap a fairly simple one," said Riso.

Since installing the Model T Trap, Grays Harbor Paper reports that its problems with wire have been greatly reduced. "We are seeing definite evidence of less wires in our systems, said Riso. "And everyday when we take the T Trap apart for cleaning, we have proof positive that it's doing its job."

Eriez is recognized as an authority in advanced technology for magnetic, vibratory, and inspection applications. Its magnetic separation, metal detection, X-ray, materials feeding, screening, conveying, and controlling equipment have applications in the process, metalworking, packaging, recycling, mining, aggregate, and textile industries. More information is available by calling 888-333-3743.