The newest OptiPress Center press section concept has a smooth, heated metal belt that goes around the center roll and guide stretcher roll. The steam-heated metal belt improves press section performance, as the temperature of the paper web increases on both sides of the press nip.
Metal belt technology has made a major breakthrough as a revolutionary new calendering concept for papermaking. Now the benefits can also be utilized in wet pressing, too. The OptiPress with metal belt technology boosts production capacity by eliminating unsupported open draws. It also increases the dry content after the press by up to six percentage points due to more effective water removal at the press nip and evaporation over the hot metal belt. Furthermore, it improves several end product qualities, such as strength and porosity.
The new concept is compact and increases dry content significantly, making it ideal for rebuilds to increase capacity by removing bottlenecks such as limited drying capacity or runnability.
Customer success story with metal belt technology: Even thinner label papers thanks to new metal belt
PM 8 at the Tervasaari mill, which produces label release base papers, went through a renovation that included a press section rebuild along with modifications throughout the paper machine line. The targets were to increase speed and further improve paper quality, as well as increasing the capacity of the paper machine by 30,000 tonnes annually.
The heart of the investment in PM 8 was the rebuild of the existing center roll-based press section with Valmet’s latest innovation: a new steam-heated metal belt application.
The new press section with metal belt technology has delivered what was promised: The draw between press and drying section has decreased significantly. Water removal is more effective as the dryness after the press has increased significantly. The concept also has positive effect on paper quality. Runnability has also improved and thanks to the rebuild the maximum speed of the paper machine has considerably increased.