| 摘要 |
The invention concerns an arrangement for identifying a web breakage in a paper web R in a papermaking machine. The arrangement comprises a blowing box 10, 10a, 10b, wherein one blows air from an inlet channel 12 into the space E inside the cover frame 11, arrow L1. From the space E inside the cover frame 11, one allows air to flow via a flow slit 13a, 13b transverse to the direction of movement of the web, which flow slit 13a, 13b is situated between the bottom piece 14 of the cover frame 11 of the blowing box 10 and the side wall pieces 15a, 15b. In the proposed arrangement, the blowing box 10, 10a, 10b is arranged in such a way in relation to the wire and web draught W/R that the bottom piece 14 of the blowing box 10 is situated at a distance from the wire and web draught W/R. One lets air flow, arrow L2, from the flow slit 13a, 13b of the cover frame 11 in the direction of the plane of the web T, thereby inducing an air flow, arrow L3, from the space D between the bottom piece 14 and the wire and web draught W/R, in which space one creates an underpressure PA. The layout includes a connection 16 which is arranged to open in the space D between the bottom piece 14 and the wire and web draught W/R. The connection 16 is connected to a pressure difference transmitter 16 and, via this, along a signal line 19, to a central unit 17, whereupon from the change in the level PA of underpressure prevailing in the space D one observes at the central unit 17 a web breakage and the fact that the web W is separated from the connection to the wire W. <IMAGE>
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