A pump assembly comprises an inlet, an outlet and a housing having an inlet aperture in fluid connection with the inlet, and an outlet aperture in fluid connection with the outlet. A rotor located within the housing is shaped to form with an interior surface of the housing a chamber. On rotation of the rotor, the chamber conveys fluid from the inlet aperture to the outlet aperture. The housing carries a seal located in the inlet and urged into contact with the rotor to prevent the passage of fluid past the rotor from the outlet to the inlet. Center lines of the inlet and the outlet are parallel to one another. The outlet can be formed by linear movement of a mold core.