| 摘要 |
1,120,275. Centrifugal blowers and compressors. COMPAGNIE ELECTRO-MECANIQUE. July 8, 1965 [July 18, 1964], No.29099/65. Heading F1C. Surging in a centrifugal blower or compressor during starting or pressure reduction is avoided by providing an annular valve member 29, Fig. 7, concentric with the impeller 22 and movable axially between the position shown, in which it makes substantially fluid-tight contact at 33 with an annular wall 25 to block the outlet fully and open fully a by-pass passage 31, and a position in which it lies flush with an annular wall 24 to fully close the by-pass passage and fully open the outlet. Guide walls 29c may be provided on the valve member 29 to guide the by-pass flow. Servomotors 32 for moving the valve member 29 may alternatively be located to the right of the wall 25, with their rods (36), Fig. 5 (not shown) projecting through holes in the wall and preferably in alignment with ribs 26 so that their slipstreams do not affect the flow. The valve member 29 is guided by the annular surface 34 and/or the ribs 26 or by a system of axial pins, and may be divided into a number of separate segments. |
