| 摘要 |
In a rotary vane positive displacement pump (28), the pump impeller (56) has weights (68-73) at the outer tips of the vanes (58-63) of greater mass per unit volume than the vanes and increasing outward centrifugal force urging engagement of the outer tips against the pump housing sidewall (44). In another embodiment, enlarged outer tips (86) of the vanes (82) are offset from the radial center-line (83) of the vane in a direction opposite the direction of rotation. In a further embodiment, a plurality of filler blades (91-96) are provided between respective vanes (101-106) and occupy space therebetween and displace volume in the pumping chamber (46). The filler blades have tapered leading edges (93a) accommodating flexure of the respective vane (103) during greatest flexure thereof. In further embodiments, the leading edges of the filler blades have a concave arcuate profile (128, 146) receiving in complementary relation enlarged outer tips (122, 138) of respective vanes upon flexure thereof.
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