Sleeve roll renews the wire section of paper and board machines

“Valmet’s new Sleeve roll technology significantly changes the operating principle of the wire section of a paper and board machine, as water is no longer removed from the web only by vacuum, but also by pressing. Pressing is a significantly more energy-efficient way to remove water from the web,” says the person who has been developing the Sleeve roll technology on a production scale. Wind Silomaa From Valmet.

The sleeve roll consists of a variable radius shoe, a static axle beam and rotating ends, which are rotated by a flexible lubricated polyurethane belt. The roll presses the web between two wires against a small radius shoe. The convex shoe bulges outside the base circle of the sleeve roll, whereby the wire tension and small radius create a high dewatering pressure, and the water is effectively removed from the web. Depending on the wire tension and radius value, very high compression pressures of up to 150 kPa can be achieved. With traditional wire section technologies, the compression pressure is typically 15–40 kPa and with a suction roll or HiVac 60–70 kPa.

“The high water removal efficiency in the Sleeve roll position reduces the need for vacuum in the wire section, which also reduces the power requirement for the wire section drives, because there are fewer dragging components. At the same time, savings are achieved in the overall energy consumption of the wire section. With traditional technology, approximately 80 percent of the wire section's energy consumption goes to the power consumption of the wire drives and vacuum technology,” says Tuuli Silomaa.

Valmet has two Sleeve roll deliveries. The first started in 2021 on a board machine refurbishment in South Korea. The second started in the summer of 2021 on a new board machine at Palm Aalen in Germany.

Last December, the French Technical Association of the Paper Industry (ATIP) awarded Valmet's innovative Sleeve roll technology and Valmet Sleeve Roll Belt the Palme d'Or award.