| 摘要 |
<p>A valve unit (24) which circulates and blocks air has a first block (21) connected to upstream suction tubes (22a, 22b), a second block (23) facing this first block (21) and connected to downstream suction tubes (22c, 22d), a shield plate (25) disposed in a space S between the first block (21) and the second block (23), and a motor (27) which rotates this shield plate (25). The shield plate (25) is provided with a connection hole which connects the upstream suction tube (22a) to the downstream suction tube (22c), and a connection hole which connects the upstream suction tube (22b) to the downstream suction tube (22d).</p> |
