Patent ID: 7290979

Claim:
A circumferential flow pump which press-feeds fuel and is equipped with a pump cover and a pump base constituting a pump chamber and a disc-shaped vane wheel rotating in the pump chamber and in which plural vane groove portions are formed along an outer peripheral wall of the vane wheel so as to penetrate through the vane wheel and so as to be trained in an outer peripheral direction of the vane wheel while partitioned by partition walls in the outer peripheral direction, and feed passages are formed in an annular form in the pump cover and the pump base respectively so as to face the vane groove portions of the vane wheel, wherein a first groove sectional area (S 1 ) of a feed passage at a pump cover side is set to be smaller than a second groove sectional area (S 2 ) of a feed passage at a pump base side, wherein an annular outer peripheral wall is formed on the outer peripheral portion of said disc-shaped vane wheel, wherein the ratio of the first groove sectional area (S 1 ) and the second groove sectional area (S 2 ) is set to satisfy 0.6≦S 1 /S 2 <0.9.