The present invention relates to a modularized pump. The pump has end lids 12, 13 with an inlet and an outlet for pumped fluid, and at least two pump modules 7 sandwiched between the end lids 12,13. Each pump module includes a casing 1 with an enclosed volume 20 and at least two pump stages 6. At least one coolant inlet 10 and outlet and a separate power connection 16 for connection to a VSD is included in each module. Each pump stage 6 includes an impeller 5 with a rotor 4, a stator 2 surrounding the rotor 4, provided to drive the rotor and a can 3 between the impeller 5 and the stator 2.