RU2733500C1 - Centrifugal pump impeller with improved positive suction bead - Google Patents

Abstract

FIELD: pumps building.

SUBSTANCE: centrifugal pump impeller comprises main disc, cover disc and vanes arranged there between. Each blade is made in the form of a bent convex surface with the beginning of construction on a segment from the diameter of the main disc to the diameter of the covering disc with turning through angle of 140–360°. Turning starts at an angle β1 between blade edge and tangent to outer circumference of main disc and ends at an angle β2 between another edge of blade and tangent to outer circle, with offset along axis by value L. Values α – inclination angle of blade leading edge, should lie in range from 30 to 90°.

EFFECT: invention is aimed at reduction of acoustic noise and hydrodynamic vibrations of pump rotor, improvement of reliability and reduction of impeller positive suction bead.

1 cl, 4 dwg

Description

Technology area

The invention relates to the field of pump engineering, in particular to designs of impellers of centrifugal pumps.

Known impeller centrifugal pump (see RF patent No. 2661801). For this pump, the angle between the tangent to the trailing edge of the blade and the tangent to the impeller circumference is in the range from 40 ° to 90 °, and the shape of the blades is described by second-order surfaces. The disadvantages of this pump are high cavitation headroom and high noise.

The closest source of information is RF patent No. 2594247 (impeller of an intermediate stage of a centrifugal pump). This intermediate stage impeller of a centrifugal pump contains a driving disc, a covering disc and blades located between them, and the covering disc is equipped with an additional seal in the form of an annular protrusion concentric with the inner protrusion of the main seal, and forming, together with the main seal, a discharge chamber. In this case, in the plane perpendicular to the impeller axis, the line connecting the inlet and outlet edges of the impeller blade is inclined to the tangent to the outer circumference of the impeller blade passing through the outlet edge of the impeller blade at an angle exceeding by 30 ° -45 ° the exit angle of the impeller blade , and the maximum distance from the line connecting the input and output edges of the impeller blade to the blade in the direction perpendicular to the above line is from 0.15 to 0.25 of the length of the line connecting the input and output edges of the impeller blade. The disadvantages of this pump are high cavitation reserves and high hydrodynamic vibrations of the rotor.

The proposed impeller makes it possible to eliminate the above disadvantages. The technical result is a significant reduction in acoustic noise and hydrodynamic vibrations of the pump rotor, a significant increase in reliability and a decrease in the cavitation reserve of the impeller.

The technical result is achieved by the fact that the impeller of the centrifugal pump contains: a main disk, a cover disk and blades located between them. In this case, each blade is made in the form of a curved convex surface, with the beginning of construction on a segment from the diameter of the main disk to the diameter of the covering disk, with a turn at an angle of 140-360 ° (at these values of the angle, the most smooth "suction" of liquid into the channels of the impeller without vortex formation), starting at an angle β1 between the blade edge and tangent to the inner circumference of the main disk and ending at an angle β2 between the other blade edge and the tangent to the outer circumference of the covering disk, with a displacement along the axis by the value L, while the values of α are the angle the slope of the leading edge of the blade should lie in the range from 30 to 90 °.

The essence of the claimed technical solution is illustrated by drawings 1-4, where

FIG. 1 - Pump impeller with the minimum possible cavitation reserve, axonometric view;

FIG. 2 - Profile of the impeller blade, front view;

FIG. 3 - Section of the impeller along the frontal plane А-А;

FIG. 4 - Profile of the impeller blade, axonometric view.

The main general objective of the present invention is to create a centrifugal pump impeller with improved technical and economic characteristics, specifically with reduced acoustic noise and hydrodynamic vibrations of the rotor, increased reliability, high resource and the minimum possible cavitation reserve of the impeller, through a complex of design improvements in its basic components. The proposed shape of the impeller blades makes it possible to “suck” liquid into the inlet funnel with the lowest possible energy losses, practically without vortex formation, i.e. with the lowest possible cavitation headroom.

The proposed invention is aimed at ensuring the maximum life cycle of the impeller and the pump as a whole, increasing its efficiency, reducing acoustic noise and hydrodynamic vibrations, and most importantly, minimizing the cavitation destruction of the pump impeller, due to the most smooth, shock-free fluid flow onto the impeller blades, providing at the same time, there are minimal eddies in the flow and minimal hydrodynamic vibrations.

FIG. 1 shows an impeller consisting of a main disk 1, a cover disk 2, blades 3.

FIG. 2 shows the profile of the impeller blade 3 - front view. The figure illustrates the construction of the number n of blades 3, thickness s, with the beginning of construction on the segment starting from the diameter D1 of the main disk 1 and ending at the diameter D2 of the cover disk 2, with a turn through an angle ϕ, while the values of the angle ϕ lie in the range from 140 to 360 °, starting at an angle β1 between the blade edge and a tangent to the outer circumference of the main disk, the values of which, in order to minimize losses from liquid inflow onto the inlet edge of the impeller blade, lie in the range from 5 to 30 ° and ending at an angle β2 between the other edge of the blade and the tangent to the outer circumference of the covering disk, the choice of the value of the angle β2 depends primarily on the maximum efficiency of the impeller, and lies preferably in the range from 3 to 60 °, with an offset along the axis by the value L. The blade constructed in this way 3, consisting of the working surface kp and the rear surface ks (see Fig. 4), is converted into an array of blades, which allows with maximum efficiency with the minimum possible losses for vortex formation, i.e. with the lowest possible cavitation margin, bring the liquid into the inlet funnel of the impeller and then transfer it along the mh and ms profiles to the diameter D3 of the outlet b from the impeller.

FIG. 3 shows a section A-A of the impeller along the frontal plane. The figure illustrates the main dimensions of the impeller, as well as the angle α - inclination of the leading edge of the blade 3. To ensure the condition of minimizing vortex formation, that is, the lowest possible cavitation margin, the values of the angle α should lie in the range from 30 to 90 °.

FIG. 4 shows a perspective view of the profile of the blade 3 of the impeller described earlier.

Claims (1)

An impeller of a centrifugal pump containing a main disk, a cover disk and blades located between them, characterized in that each blade is made in the form of a curved convex surface, with the beginning of construction on a segment from the diameter of the main disk to the diameter of the cover disk, with a turn at an angle of 140- 360 °, starting at an angle β1 between the blade edge and the tangent to the inner circumference of the main disk, and ending at an angle β2 between the other blade edge and the tangent to the outer circumference of the covering disk, with an offset along the axis by the value L, while the values of the angle α the slope of the leading edge of the blade should lie in the range from 30 to 90 °.

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