MULTISTAGE CENTRIFUGAL PUMP Russian patent published in 2023 - IPC F04D29/22 

FIELD: hydraulic engineering.

SUBSTANCE: invention relates to the field of hydraulic engineering, namely to multistage high-pressure centrifugal pumps, and can be used in pumps for pumping feed water to thermal power plants, as well as to thermal power stations and nuclear power plants with power units with a capacity of 200-1200 MW. The expected result is achieved by the fact that a multi-stage centrifugal pump containing a housing with a supporting end collar, a pressure cap, a flow part resting on a supporting end collar on the pump housing and formed by steps connected to a common block consisting of sections, impellers and vane wheels, except for the latter, guiding devices, the guiding device of the last stage has tubular structure, is combined with the last section, on the end surface, from the side of the pressure cap of the pump, the tubular guide device (TGD) of the last stage rests against spring nodes consisting of helical cylindrical springs, spring nodes are located in the blind holes of the pressure cap, differs in that the spring nodes are located in blind holes on the end surface of the TGD of the last stage from the side of the pressure cap of the pump and rest against the end surface of the pressure cap, spring nodes consist of their packages of disk springs, and the last stage of the pump is made with a speed coefficient in the range n_S = 60…120, at the same time, the ratio of the diameter of the entrance to the cylindrical channels of the TGD to the outer diameter of the impeller (D3/ D2) varies within 1.02…1.04, the cylindrical section of the TGD channel with a diameter of d₀ and a length of L is connected by the ratio L₀/d₀= 0.7…1.0, the ratio of the diameter of the exit from the channels of the TGD of the guide device to the outer diameter of the impeller (D4/D2) varies within 1.7…2.1, and the values of the diffusivity angle of conical holes in the TGD are in the range α_dif =4…5°, the ratio of the areas of the output and input sections of conical holes in the TGD varies within 2.2…2.6.

EFFECT: tasks to be solved by the invention are to increase the strength of the pressure cover of the pump, increase the stiffness of the spring assembly and the magnitude of the axial force for pre-compression of the flow part to the thrust end collar of the pump housing and for the reliability of sealing along the end collar, to exclude fluid leakage from the high pressure area behind the last stage TGD to the low pressure area behind the 1^st pump stage at the pump start and stop modes, which increases the reliability of the pump, as well as optimization of the geometry of the flow part of the last-stage TGD to obtain its optimal hydraulic efficiency and the efficiency of the pump as a whole.

1 cl, 2 dwg