Porous aerostatic bearings for paper machine roll deflection compensation

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master_Harding_Luke_2025.pdf (26.29 MB)

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School of Engineering | Master's thesis
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Date

2025-06-14

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Mcode

Degree programme

Master's programme in Mechanical Engineering

Language

en

Pages

63

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Abstract

The paper and board industry is in need of a new method to reduce friction in deflection compensated paper machine rolls. State-of-the-art deflection compensation solutions feature hydrostatic loading shoes that require high-pressure oil for operation. These shoes produce kilowatts of friction per roll and have experienced catastrophic failures resulting in expensive losses in infrastructure and machine down time. The oil film thickness and oil viscosity limit the possibilities for further friction reduction in this area; however, using high-pressure air instead of oil could be a feasible solution while maintaining equal levels of loading force. In this study, an aerostatic loading shoe for deflection compensated paper machine rolls was constructed and tested in a laboratory environment at half scale. A measurement frame to quantify the maximum loading force and friction force of the loading shoe was also constructed. The study focused on the relationship between the loading force and force of the aerostatic loading shoe at a maximum web speed of 990 m/min (16.5 m/s). The results show that aerostatic deflection compensation is possible with line loads that are below 100 kN/m. The friction power losses from the aerostatic loading shoes are an order of magnitude smaller than the current hydrostatic solutions. This research was successful in filling a research gap in the paper and board machine industry and gives a solid foundation for future research into aerostatic deflection compensation methods.

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Supervisor

Viitala, Raine

Thesis advisor

Miettinen, Mikael

Keywords

gas seal, paper calendering, air bearing, aerostatic seal, friction reduction, low-friction

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https://urn.fi/URN:NBN:fi:aalto-202508196373

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[dipl] Insinööritieteiden korkeakoulu / ENG