| 摘要 |
PURPOSE:To reduce noise of a pump by specifically shaping the inwall face continuing to the vane-retraction-side edge of th inlet of a discharge chamber to produce counter-flow, which attenuates the flow of air which is to be collected and jammed by a rotor into the opening of a slit thereon. CONSTITUTION:The inwall face 37 which continues to the vane-retraction-side edge of the inlet 32 of a discharge chamber 30 is formed flat, containing the tangential line Z-Z of a rotor 7 which runs from the external peripheral face thereof opposed to the inlet 32 thereof through the vane-retraction-side edge. In the vicinity of the vane-retraction-side edge of the inlet 32 of the discharge chamber 30, downward air flow in the direction (b) along the external peripheral face of the rotor 7 collides against the flow of a part of air rising along the inwall 37, as shown by the arrow C, after discharged into the discharge chamber 30. Such counter-flow operation by the inwall face 37 may attenuate the flow of air which is to be collected and jammed into the clearance between the rotor 7 and the land part L. The reduction of jammed quantity of air into the opening part of each slit 18 on the rotor 7 results in noise suppression.
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