| 摘要 |
1461103 Paper-making K WATANABE 5 March 1974 [12 March 1973] 9943/74 Headings D2A and D2B To make paper which does not curl due to alignment of the fibres during manufacture, stock is fed for drainage by gravity onto a linear section 2a of a first foraminous belt 2 upstream of a rotatable porous roll 1 around which the web is formed as the stock is dewatered by centrifugal force and surface pressure between the belt 2 and a second foraminous belt 3 which converges with the belt 2 at the roll 1 to define a throat 12, the web being then passed to a transfer roll 5, subsequent to which the belts 2, 3 diverge, before passing to a porous roll 6 for transfer to a conveyor 17. The roll 6 further dewaters the web and a biassing roll 18 assists its transfer from the belt 2 to the conveyor 17. Although the fibres of an underlayer P 1 of the web become aligned, the stock in a top surface layer P 2 suffers turbulence in the throat 12 so that the fibres in this layer P 2 become randomly oriented. If two headboxes 9, 9n are used, stock from box 9 produces layer P 1 and stock from box 9n produces layer P 2 , the thicknesses of layers P 1 , P 2 being controlled by varying the quantities of stock discharged from the headboxes 9, 9n. Rolls 10, 11 can be adjusted to vary the angle (α) of the throat 12. Traps 21, 22 collect white water and traps 23, 25 collect water discharged from nozzles 24, 26 for cleaning the belts 2, 3. A composite web may be formed by providing a series of machines each transferring a web onto a common conveyor 17 (Fig. 3 not shown). |
