| 摘要 |
<p>The present invention relates to: a bubble generator which has a plurality of balls or rollers interposed between an inner pipe having through-holes on the circumferential surface thereof and an outer pipe having or not having through-holes on the circumferential surface thereof such that the inner pipe is rotated in order to enable the plurality of balls or rollers to block the plurality of through-holes; or a bubble generator which rotates an inner pipe from among an inner pipe having through-holes on the circumferential surface thereof and an outer pipe having through-holes on the circumferential surface thereof, and which is circumscribed by slidably coming in contact with the inner pipe, so as to block the plurality of through-holes of the inner pipe by the outer pipe.</p> |
