A blind-drilled press roll is a press roll with a specially designed cover surface containing thousands of blind holes, small holes that do not pass completely through the roll cover. These holes act as temporary water reservoirs during the pressing process.
When the wet paper web passes through the press nip between the press rolls, water is squeezed out of the sheet. The blind holes provide space for that water to enter momentarily, reducing the chance of water flowing back into the sheet. This improves the efficiency of dewatering and supports higher dryness levels after the press section.
In modern papermaking, the press section plays a decisive role in improving sheet dryness, reducing energy consumption, and preparing the paper web for efficient drying. Among the many roll types used in this section, the Blind-Drilled Press Roll is one of the most important for optimizing dewatering performance and press stability.
Designed with a surface covered in numerous non-through drilled holes, the blind-drilled press roll is engineered to temporarily absorb and store water squeezed out of the paper sheet during the press nip. This helps prevent water from returning to the sheet, improves dryness after pressing, and enhances the overall efficiency of the paper machine.
As paper machines continue to run at higher speeds and demand better energy performance, the blind-drilled press roll has become an essential solution for advanced press section design.
Blind-drilled rolls are commonly used in combination with press felts, suction rolls, shoe presses, or other press section rolls, depending on the machine design and paper grade.
1. Improving Dewatering Efficiency
The most important function of a blind-drilled press roll is to enhance water removal in the press nip. The blind holes temporarily store the expressed water, allowing the sheet to exit the nip with lower moisture content.
2. Reducing Rewetting
Without proper water handling, some of the water removed during pressing can flow back into the paper sheet. Blind holes help minimize this rewetting effect, resulting in higher outgoing dryness and better press efficiency.
3. Supporting Stable Nip Performance
The roll cover structure helps optimize pressure distribution and water handling inside the nip. This contributes to stable press performance and more uniform dewatering across the machine width.
4. Lowering Energy Consumption
Higher sheet dryness after the press section reduces the load on the dryer section, leading to lower steam consumption and improved energy efficiency.
Diameter: 700–1,500 mm
Face Length: 2,000–10,500 mm
Cover Material: rubber, polyurethane, composite, or engineered elastomer
Blind Hole Diameter: typically 2–4 mm, depending on application
Blind Hole Depth: customized according to dewatering requirements
Open Area Ratio: optimized for press performance and sheet support
Operating Speed: up to 2,000 m/min or higher
Dynamic Balance: ISO 21940 G2.5 or better
Runout Tolerance: typically ≤0.02 mm