| 摘要 |
<p>The invention relates to a system of loading and controlling a press nip in a paper or board machine. The press nip (N) is formed as an extended nip press which comprises a loading shoe (14) which is arranged to be loaded by means of two loading cylinders (26, 27). The loading shoe (14) is pressed against a backing roll (2) which includes a backing shoe (28). The system of loading and controlling the press nip (N) comprises at least two valves (22, 23) and loading medium lines (30, 24, 25) passing from the valves (22,23) to the loading shoe (14) and the backing shoe (28). One valve (22) is arranged to be employed for loading the first loading cylinder (26) of the loading shoe (14) of an extended nip roll (1), as viewed in the running direction (S) of the web, and for loading a loading cylinder (29) of the backing shoe (28) of the backing roll (2). The other valve (23) is arranged to be employed for loading the second loading cylinder (27) of the loading shoe (14) of the extended nip roll (1), as viewed in the running direction (S) of the web. Check valves (31, 32, 33) are fitted in lines (34, 35) between the loading medium lines of the valves (22) and (23), which check valves allow pressure to pass from the side of higher pressure to the side of lower pressure when the loading pressure exceeds a given limit value.</p> |
