A centrifugal pump has a pump unit and a drive unit. The pump unit includes a volute and an impeller disposed in the volute. The drive unit has a stator and a rotor having a shaft. The volute includes an inlet, an outlet and a chamber in communication with the inlet and outlet. The inlet is coaxial with the chamber. The shaft of the rotor extends into the chamber of the volute and the impeller is attached to and driven by the shaft. The volute further includes a baffle installed in the inlet. The baffle includes a guide plate angled to the axis of the inlet.