| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative pressure generating device with a simple construction, the device capable of controlling a negative pressure generated proportionally to a rotational speed of a fan.SOLUTION: A negative pressure generating device has a multi-blade fan 2 constituted such that a large number of blades 22 are stood on a disk-shape base material 21 at predetermined intervals in a peripheral direction while making an angle in a radial direction to have a drum-like contour, a fan casing 3 having an end face making a ring-shape gap 33 with a ring-shape frame 23 connecting the other ends of the respective blades, covering from the side of the frame 23 to the blades 22 of the multi-blade fan 2, and in which an air suction opening 34 is opened in an axial line passing through the rotational center of the multi-blade fan 2, and a motor 4 rotating and driving the multi-blade fan 2. The device further has a relative adjusting means 6 adjusting the relative positions of the ring-shape frame 23 and the end face of the fan casing 3. |
