093 4951 Behrendt und Rausch

Making it all add up

ANDRITZ has recently completed a service at Mayr-Melnhof’s FS Karton mill, involving one MG cylinder, two web stabilizers, three dryer cylinders, and a fourth headbox service. From order to completion, it all added up to four service operations in just four months.

Although it started up back in 1990, the 5.25 m wide, 350,000-tonne BM5 at FS Karton in Neuss is still one of the largest and most modern recycled boxboard machines in Europe. And every January, the mill makes sure it stays that way – with new improvements.

Udo Koolen, FS Karton’s Project Engineer, explains why FS Karton chose ANDRITZ to carry out the latest upgrades. “ANDRITZ knows the machine – they built it. But also, I like that we got everything from one supplier that took responsibility for all the work, including the actual installation – not all suppliers offer that.”

BM5 uses four fourdrinier formers to make boxboard - first top layer, second top layer, filler layer, and back layer. As part of a full headbox service, ANDRITZ installed new bottom and top slice lip and renewed all seals. “We took it completely apart,” says Johannes Kraxner, Service Manager, ANDRITZ Tissue, Paper & Board Machines, “which has given us benefits such as improved cross-direction and machine-direction basis-weight control and correct sealing on the mixing chamber right from the start-up.”

spectrum35-neuss_004

"Technologically, everything went smoothly. We did what we planned to do and achieved everything we wanted.”

UDO KOOLEN
FS Karton Project Engineer

DRYING CYLINDERS – “A VERY SKILLED JOB”

Downstream, the dryer section at Neuss comprises 44 pre-drying cylinders before the MG cylinder, followed by 21 after-drying cylinders. ANDRITZ installed three new 1.8 m diameter, 5.7 m long, PrimeDry Steel cylinders in the pre-dryer section, replacing three cast-iron cylinders.

The new steel cylinders can operate at much higher parameters (6 bar pressure, 1,200‑m/min speed) than the cast-iron cylinders. For now, though, Neuss has already achieved its immediate goals of more homogenous heat transfer, smooth runnability, safety, and a return to design quality.

And it wasn’t easy. Koolen comments, “I was very impressed with how ANDRITZ installed the drying cylinders. It was a very skilled job; they had to be precise down to the millimeter.”

In January 2017, ANDRITZ carried out a suite of service upgrades on the 350,000-tonne BM5 at Mayr-Melnhof’s FS Karton mill in Neuss, Germany, the largest recycled boxboard machine in Europe.

ANDRITZ has now serviced all four headboxes at Neuss during the past five years. The most recent upgrade was for the filler ply, which restored the headbox’s full technical functionality, enabling it to reach the desired process and quality parameters. 

MG CYLINDER – A BALANCING ACT

Although the MG cylinder is in the middle of the dryer section and runs hot, it is not actually used for drying. Instead, it ensures a smooth printing surface on the white top layer of the cartonboard and liner produced on BM5.

Over time, line pressure had resulted in the MG cylinder becoming marginally eccentric, by 0.6‑mm over a diameter of 6,400 mm – but even that was enough to require re-grinding of the cylinder. “It wasn’t a problem that was obviously noticeable,” Koolen says, “but it was causing the cylinder’s three doctors to move and was affecting the main bearings."

The grinding reduced the overall diameter by 1 mm, ensuring that the MG cylinder was perfectly round and smooth again, increasing machine stability and product quality.

The service in January also included two new PrimeRun M web stabilizers, in addition to two PrimeRun M units that ANDRITZ had installed six months earlier.

Koolen concludes, “Technologically, everything went smoothly. The sealing in the headbox worked. The cylinder set-up was a reward for good preparation and discussions between ANDRITZ and us. We did what we planned to do and achieved everything we wanted and the start-up took place with no project-related problems at all.”

spectrum35-neuss_005

"We were working for the future here. The customer is happy and they know how much we did. We have to work like we’re on the same team.”

JOHANNES KRAXNER
ANDRITZ Service Manager

Contact us
Downloads
  • SPECTRUM 35, Neuss: Making it all add up PDF : 1.3 MB