A pump comprises a housing, with an interior defining a rotor path, an inlet formed in the housing at a first position on said rotor path, an outlet formed in the housing at a second position on said rotor path spaced from said first position. A rotor is rotatable in the housing with a first surface that seals against the housing. A second surface is formed on said rotor circumferentially spaced from said first surface and forms a chamber that travels around said rotor path to convey fluid from the inlet to the outlet. A resilient seal formed with the housing is located on the rotor path to prevent fluid flow from said outlet to said inlet past the seal. A passage may be provided to supply fluid to an under surface of the seal at a pressure that acts to urge the seal against the rotor.