| 摘要 |
The appts. (10) to coat the surface of a moving web (22), with a liquid or paste coating medium (16), has a jet lip (32) at the outlet side of the coating flow (18) which is longer than the jet lip (30) at the web entry side. The coating flow (18), according to the coating medium (16), is defined by a convex surface section (32a) at the jet lip (32) which projects over the entry lip (30). The coating flow can pass over a concave surface section at the outlet jet lip, before it reaches the convex surface section, in the delivery direction. Or the flow can move over a concave surface section at the jet lip on the web entry side, before it reaches the concave surface section at the jet lip on the outlet side. The two concave sections are formed by flats on a circular cylinder, where the radius for the concave section at the entry jet lip of 10-100 mm is pref. longer than the radius of the concave section at the outlet lip of 1-20 mm. The angular extent of the cylinder flat for the entry side of 10-90 deg is pref. greater than that of the flat for the concave section at the jet lip on the outlet side of 30-120 deg . The jet lip (32) at the outlet side has a flat surface section (32c) in the delivery direction of coating (16). The coating flow (18) meets the coating surface (22) at an angle ( beta ) of 5-75 deg . A setting mechanism (34) acts on the jet lip (30) at the entry side and/or the outlet side, to vary the gap between the jet lips (30,32), with setting units (34) at intervals across the web (22) width to alter the coating jet gap at local points. The coating medium (16) is delivered across the width of the free-stream jet applicator (12) by a distribution tube (26) at the entry side or the outlet side.
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