A multistage centrifugal pump for pumping liquids including: • a leak-tight chamber including a shaft going through it, said shaft projecting from said leak-tight chamber through a rotary mechanical seal and defining a shaft axis; • a motor placed outside said leak-tight chamber connected to said shaft for operating same; • a cylindrical chamber coaxial with said shaft, integrated in said leak-tight chamber; • at least one liquid inlet placed in a position close to or coinciding with a first end of said cylindrical chamber, said liquid inlet being connected with at least one inlet mouth; • at least one liquid outlet placed in a position close to or coinciding with a second end of said cylindrical chamber opposite the first end, said liquid outlet being connected to at least one outlet mouth through the mentioned leak-tight chamber; • a plurality of drive impellers attached to said shaft for rotating integrally therewith, and inscribed in said cylindrical chamber, said liquid being driven and the liquid pressure successively increased from the first end to the second end of the cylindrical chamber by the rotation of said drive impellers; characterized in that • the inlet mouth and the outlet mouth are, each one, defined on a plane inclined 45° with respect to the shaft axis, said planes being parallel or perpendicular to each other; • a connecting element is hermetically coupled to each one of said inlet mouth and outlet mouth by coupling means and each connecting element is also connectable to a pipe; • the connecting elements are configured to provide: • a first coupling configuration in which the pipe attached to said connecting element of the inlet mouth is parallel to the shaft axis, • a second coupling configuration in which said pipe attached to said connecting element of the inlet mouth is perpendicular to the shaft axis; • a third coupling configuration in which a pipe attached to said connecting element of the outlet mouth is parallel to the shaft axis, and • a fourth coupling configuration in which the mentioned pipe attached to said connecting element of the outlet mouth is perpendicular to the shaft axis. • a leak-tight chamber including a shaft going through it, said shaft projecting from said leak-tight chamber through a rotary mechanical seal and defining a shaft axis; • a motor placed outside said leak-tight chamber connected to said shaft for operating same; • a cylindrical chamber coaxial with said shaft, integrated in said leak-tight chamber; • at least one liquid inlet placed in a position close to or coinciding with a first end of said cylindrical chamber, said liquid inlet being connected with at least one inlet mouth; • at least one liquid outlet placed in a position close to or coinciding with a second end of said cylindrical chamber opposite the first end, said liquid outlet being connected to at least one outlet mouth through the mentioned leak-tight chamber; • a plurality of drive impellers attached to said shaft for rotating integrally therewith, and inscribed in said cylindrical chamber, said liquid being driven and the liquid pressure successively increased from the first end to the second end of the cylindrical chamber by the rotation of said drive impellers; • the inlet mouth and the outlet mouth are, each one, defined on a plane inclined 45° with respect to the shaft axis, said planes being parallel or perpendicular to each other; • a connecting element is hermetically coupled to each one of said inlet mouth and outlet mouth by coupling means and each connecting element is also connectable to a pipe; • the connecting elements are configured to provide: • a first coupling configuration in which the pipe attached to said connecting element of the inlet mouth is parallel to the shaft axis, • a second coupling configuration in which said pipe attached to said connecting element of the inlet mouth is perpendicular to the shaft axis; • a third coupling configuration in which a pipe attached to said connecting element of the outlet mouth is parallel to the shaft axis, and • a fourth coupling configuration in which the mentioned pipe attached to said connecting element of the outlet mouth is perpendicular to the shaft axis. • a first coupling configuration in which the pipe attached to said connecting element of the inlet mouth is parallel to the shaft axis, • a second coupling configuration in which said pipe attached to said connecting element of the inlet mouth is perpendicular to the shaft axis; • a third coupling configuration in which a pipe attached to said connecting element of the outlet mouth is parallel to the shaft axis, and • a fourth coupling configuration in which the mentioned pipe attached to said connecting element of the outlet mouth is perpendicular to the shaft axis.