| 摘要 |
<p>A short dwell coater apparatus (10A) is disclosed for coating a web (WA) with a coating material, the web moving contiguously with a rotating backing roll (26A). The apparatus (10A) includes a housing (12A) which is disposed on the opposite side of the web relative to the backing roll (26A). The housing defines a coating chamber (14A) having an upstream and a downstream end (18A,20A). The chamber is connected to a pressurized source (16A) of coating material. The chamber is exposed to the web such that the web supported by the backing roll (26A) is coated with the coating material during passage of the web past the coating chamber (14A). The upstream and downstream ends (18A,20A) of the coating chamber define first and second weirs (22A,28) respectively. Each of the weirs (22A,28) extend in a cross-machine direction such that the coating chamber (14A) is bounded by the weirs and the web moving between the weirs. The first and second weirs (22A,28) define respectively first and second overflow gaps (30,32). The arrangement is such that during use of the apparatus (10A), when the web moves past the coating chamber, coating material is coated onto the web (WA) while excess coating material overflows through the first and second gaps (30,32) for recirculating through the coating chamber. A resilient blade (24A) is disposed downstream relative to the second weir. The blade (24A) cooperates with the coating material coated onto the web such that the pressure exerted by the coating material on the blade is less than the pressure of the coating material within the coating chamber, so that mottling and streaking of the resultant web (WA) is inhibited while maintaining minimum pressure on the blade (24A).</p> |
