| 摘要 |
PURPOSE:To reduce the noise generated in the terminal of a pump passage by the rotation of an impeller. CONSTITUTION:A casing cover 37 has a grooved pump passage 4 formed thereon, and a damping part 51 is formed on the terminal part of the pump passage 44 extending over a discharge port 46. The damping part 51 is shallower than the pump passage 44 and enclosed by a vertical wall 51a. Further, it has an oblique wall surface (border line) 51c for gradually entering the vane piece of the impeller into a partitioned part 47, and is tapered along the rotating direction of the impelled. According to this form, noise is reduced, and the form change of the damping part 51 is suppressed even when cutting work is added to enhance the plane precision of the casing cover. The reduction in noise is attained by the formation of the damping part shallower than the main range of the pump passage extending over the discharge port 46, and the formation of the oblique wall surface (border line) 51c for gradually entering the vane piece of the impeller into the partitioned part 47 on the terminal of the pump passage.
|
