| 摘要 |
A low inertia, low friction roller (12), which is particularly adapted for handling relatively high speed, relatively fragile running webs, comprises an inner tube (16) and an outer tube (14). The outer tube (14) is disposed substantially coaxially about the inner tube (16) and is rotatable with respect to the inner tube (16). An annular gap (46) is defined between the inner and outer tubes and has a first portion that is supplied with a restricted flow of a pressurized compressible fluid and that is adjacent the portion of the outer tube about which the web passes. A second portion of the annular gap is circumferentially spaced from the first portion of the annular gap and communicates with a fluid exhaust passage (66) in the inner tube. The dimensions of the annular gap are selected so that the fluid pressure in the first portion is greater than the fluid pressure in the second portion and so that the pressure of the fluid in the first portion of the annular gap will substantially balance the force exerted by the web on the outer tube as the web passes about the outer tube. The Figure shows an enlarged, partial cross-sectional view.
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