Two-stage centrifugal pump

Abstract

The invention provides a two-stage centrifugal pump capable of preventing a decrease in pump efficiency by minimizing a flow loss (energy loss) of a liquid flowing through a guide vane member. In the multistage centrifugal pump, two impellers are mounted on a rotor shaft in the axial direction, each impeller is accommodated in each of two pump chambers partitioned in a pump housing by a partition wall, and a guide vane member is interposed between axially adjacent impellers. A diffusion passage divided by a plurality of diffusion blades is formed on a surface facing the front surface of the base portion, a return passage divided by a plurality of return guide blades is formed on a rear surface facing the partition wall of the base portion, and a plurality of interpolation portions are provided on a surface facing the guide blade member of the partition wall in a protruding manner along the circumferential direction. The plurality of interpolation parts are used for filling a step difference (delta) formed between the surface of the partition wall facing the guide vane member and the outer peripheral opening end of each diffusion passage of the guide vane member.

Description

[0001] The present invention relates to a two-stage centrifugal pump having a guide vane member for guiding fluid discharged from a first-stage impeller to the suction side of a second-stage impeller. Background technique [0002] In a multistage centrifugal pump as one form of a fluid machine, as in Patent Documents 1 and 2, there is a structure in which a plurality of impellers are axially attached to a rotor shaft rotationally driven by a drive source such as an electric motor, and The respective impellers are accommodated in a plurality of pump chambers defined in the pump housing, and guide vanes are respectively interposed between two impellers adjacent to each other in the axial direction via the partition wall in the pump housing. part. Here, the guide vane member has: a base portion having a center hole through which the rotor shaft can be inserted; The function of converting kinetic energy (boosting) of the treatment fluid into static pressure (diffusion function); ...

AI Technical Summary

Problems solved by technology

[0004] In addition, in Image 6 A part of the internal structure of a conventional two-stage centrifugal pump that functions as described above is shown in the cutaway perspective view of FIG. A sharp step difference δ is formed between the outflow ports 132a opened at the outer peripheral ends of the plurality of diffuser passages 132 formed in the guide vane member 110 of the partition wall 121A.

Therefore, the flow direction of the liquid flowing in the direction of the arrow in the figure in each diffusion passage 132 changes abruptly at the step difference δ, and the liquid cannot smoothly flow to each return passage 134. As a result, the flow loss of the liquid (energy loss ) becomes larger, leading to a decrease in pump efficiency in many cases

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