| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate a noise by improving a sucking efficiency and obviating looseness and to set an opening/closing shutter in the state of opening halfway. SOLUTION: A suction side joint tube 31 is mounted in a hole 27 formed at a mounting base plate 23 mounted on a wall 5. A front plate 33 having an opening for mounting a hood side joint tube 51 is mounted on a front surface of the plate 23. An openably and closably opening/closing shutter 39 for opening/ closing the tube 31 and the tube 51 is disposed in a gap 37 formed between the plate 23 and the plate 33. A valve 55 for urging a one-end opening 31A of the tube 31 when the shutter 39 is opened and urging the shutter 39 when the shutter 39 is closed, is fitted inside the tube 51.</p> |
