RU2142068C1 - Centrifugal pump impeller - Google Patents

Abstract

FIELD: centrifugal pumps and air blowers. SUBSTANCE: impeller includes drive disk, driven disk and bladed disk which form multirow radial passages. Blades located in passages are shifted circumferentially. Walls of side passages which are closer to periphery are taper in shape. Walls directed to opposite sides from plane of symmetry of impeller are intersection in its plane of symmetry over circumference whose length is equal to length of arc of all passages plus thickness of walls between adjacent passages. Peripheral section of impeller has peripheral radial passage arranged in one row and communicated with radial passages of all rows through circular space which may be divided into sectors. EFFECT: enhanced efficiency; reduced starting torque due to reduction of eddy flows in impeller. 2 cl, 10 dwg

Description

 The invention relates to the field of pump engineering, and in particular to designs of impellers of centrifugal pumps; can also be used in centrifugal blowers.

 Known impeller, containing the driving and driven disks and installed between them radial blades, forming at the entrance of the wheel between the disks two or three rows of interscapular channels [1].

 Closest to the technical nature of the proposed is the impeller, containing the driving, driven and blade disks forming radial channels in which the blades are located, displaced in the circumferential direction [2].

Significant disadvantages of both the first and second designs are:
low efficiency due to the formation of a vortex flow in the interscapular channels;
increased starting torque, due to the expansion of the total width of the channels on the periphery of the wheel in the first case and the fact that the total width on the periphery of all channels remains unchanged - in the second.

 The aim of the invention is to increase efficiency and reduce starting torque.

 This goal is achieved by the described impeller, including the driving, driven and blade disks forming radial channels in which the blades are located, displaced in the circumferential direction.

What is new is that the walls of the lateral radial channels closer to the periphery are conical, and the walls facing in opposite directions from the plane of symmetry of the impeller intersect each other in its plane of symmetry along a circle whose length is equal to the length of the arc of all channels plus wall thickness between adjacent channels the channels of one row are displaced in the circumferential direction from the channels of the adjacent row by an angle of 360 ^o / n (where n is the number of rows) and in the plane of symmetry they form one row (central) and are provided on the peripheral section with radial channels of one row communicating with the radial channels of all rows through the annular space.

 Also new is the fact that peripheral single-row radial channels communicate with radial channels of all rows through sector sections of the annular space.

In FIG. 1 shows a longitudinal section of the proposed impeller;
in FIG. 2 is a section AA of FIG. 1,
in FIG. 3 is a longitudinal section of the impeller with 3-row channels communicating with peripheral single-row channels through the annular space;
in FIG. 4 is a view of the impeller (Fig. 3) in plan with the driven disk removed;
in FIG. 5 - in terms of channels "5" of FIG. 3;
in FIG. 6 - in terms of channels "6" of FIG. 3;
in FIG. 7 - in terms of channels "4" of FIG. 3;
in FIG. 8 is a longitudinal section of the impeller with 2-row channels communicating with peripheral single-row channels through the annular space;
in FIG. 9 is a view of the impeller (Fig. 8) in plan with the driven disk removed;
in FIG. 10 - wall thickness between adjacent channels.

The impeller (Fig. 3) consists of a leading 1, driven 2 and blade 3 disks. In the latter, 3- or 2-row radial channels 4, 5 and 6 are made. The walls of the side channels 4 and 5 closer to the periphery with a diameter of D ₁ are conical, with the walls 7 and 8 facing in opposite directions from the plane of symmetry of the impeller intersect with each other in its plane of symmetry around the circle D ₂ , the length of which is equal to the length of the arc of all channels plus the wall thickness between adjacent channels. The optimal value of the diameter D ₂ is determined from the expression.

где L - длина канала по дуге окружности D₂;
t - толщина лопатки на диаметре D₂;
n - количество каналов, выходящих на диаметр D₂.PD ₂ - (L + t) _n ;

where L is the length of the channel along the arc of a circle D ₂ ;
t is the thickness of the blade on the diameter D ₂ ;
n is the number of channels facing the diameter D ₂ .

The inner walls of the channels 6 of the 3-row impeller, which are facing the axis of symmetry, do not pass into the conical surfaces at the periphery. The channels of one row are shifted in the circumferential direction from the channels of the adjacent row by 360 ^o / n (where n is the number of rows) and form one row (central) in the plane of symmetry. All channels with diameters D ₃ go to a strip bounded by two transverse planes 9 and 10. At the periphery of the impeller there are made radial (single-row) channels 11 formed by blades 12. An annular space 13 is enclosed between concentric circles formed by diameters D ₂ and D ₃ .

Two options for the annular space 13 are proposed: solid and discontinuous. In the first case, the beginning of all the blades of the peripheral row lies on the diameter D ₄ , and the ends of the blades related to multi-row channels on the diameter D ₃ (Fig. 5). In the second case, some blades forming multi-row channels pass into the blades of the peripheral row (Fig. 4, 6, 7, 9) and divide the annular space 13 into separate sectors. At D ₄ / D ₀ ≥5, the annular space is made intermittent, and at D ₄ / D ₀ ≤5 it is continuous. In FIG. 5, 6, 7 indicate the angle between sectors equal to 120 ^o ; This is one of the possible options. And in practice, it can vary between 60 -180 ^o .

 The impeller operates as follows: when it rotates, the fluid from the cavity "a" is sent to the channels 4, 5 and 6 (Figs. 3 and 8), having passed their radial and inclined sections, it enters the annular space 13. Here the pressure and velocity of the fluid are stabilized , and then the liquid enters the radial channels 11 (Fig. 4, 5, 6, 7, 9), from which it is forced into the channels of the guide apparatus.

 The execution of the walls of the side channels closer to the periphery of the conical allows you to achieve the optimal diffusivity of the channels in the Central and peripheral sections and to drastically reduce the vortex flows in the channels and thereby increase the efficiency and reduce the starting torque.

The shift of the channels of one row in the circumferential direction from the channels of the adjacent row by an angle of 360 ^o / n allows a smooth transition of the side channels into one central row of channels with optimal diffuser, which also reduces vortex flows and leads to an increase in efficiency and lower starting torque.

 In the annular space, the fluid flow is equalized in terms of speed and pressure. This space serves as if as a suction strip for the peripheral portion of the impeller. The liquid flow exiting from all the channels in the annular space calms down, from where it enters the channels of the peripheral row, which actually serves as the second stage of the impeller. In this case, the vortex formation almost completely disappears, and this leads to an increase in efficiency.

Information used
1. US patent N 3478691, MKI F 04 D 29/22, 1969

 2. A.S. N 1117410, MKI F 04 D 29/18, 1984

Claims (2)

 1. The impeller of a centrifugal pump, including a driving, driven and impeller disks forming multi-row radial channels in which the blades are located, displaced in the circumferential direction, characterized in that the walls of the side channels closer to the periphery are made conical, with the walls facing in opposite directions from the plane of symmetry of the impeller, made intersecting each other in its plane of symmetry around a circle, the length of which is equal to the length of the arc of all channels plus the wall thickness between adjacent channels, and peripheral section of the wheel is made of peripheral radial channels placed in one row and communicated with the radial channels of all rows through the annular space.  2. The wheel according to claim 1, characterized in that the annular space communicating peripheral and multi-row channels is divided into sectors.

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