The irg is a vertical non-self-priming multistage centrifugal pump driven by a standard electric motor. The motor output shaft is directly connected to the pump shaft through a coupling. The flow passage parts of the pressure-resistant cylinder abd are fixed between the pump head and the inlet and outlet parts with strut bolts. The inlet and outlet are located on the same plane at the bottom of the pump. Such pumps can be equipped with intelligent protectors to effectively prevent dry running, out-of-phase and overload.