| 摘要 |
PCT No. PCT/SE84/00004 Sec. 371 Date Sep. 11, 1984 Sec. 102(e) Date Sep. 11, 1984 PCT Filed Jan. 11, 1984 PCT Pub. No. WO84/02772 PCT Pub. Date Jul. 19, 1984.Apparatus for measuring thickness, two light measuring heads (2, 3) being mounted by air bearings in housings on either side of the web (1). The measuring heads are provided with specially implemented nozzles blowing against the surface and maintaining a constant distance of 60-100 m to the respective paper surfaces. The thickness is measured by the distance between the nozzles being measured via an electrical measuring probe (13) in one, and a means (13') sensed by the measuring probe. By the special implementation of the nozzles (12, 12') and by their being pneumatically pressing (via 11) against the surfaces, great accuracy (better than 0.5 m) is achieved even if the position of the paper is altered, rapidity also being considerable. The time to indication for a thickness alternation of about 100 mu is about 0.5 msec. |
