A high efficiency multistage pump

Abstract

The invention discloses a high-efficiency multistage pump, which comprises a segmented pump casing (1), a centrifugal impeller (2), a partition (3), a positive guide vane (4), and a reverse guide vane (5), wherein the segmented pump casing has a radial section (11); the centrifugal impeller comprises a front disc (21), a rear disc (22), a blade (23), and an inlet ring (24), wherein the blade has a blade leading edge (26), and the reverse guide vane has a reverse guide vane trailing edge (51); the pump is characterized in that a sealing groove (52) is provided on the reverse guide vane, the upstream end of the inlet ring is embedded in the sealing groove, the left side surface of the radial section (11) is used as a reference surface, the upstream end surface of the inlet ring is located on the left side of the reference surface, and the reverse guide vane trailing edge is substantially located on the right side of the reference surface. The invention can effectively improve the sealing effect between the reverse guide vane and the next-stage impeller, reduce the backflow and turbulence at the impeller inlet, and reduce the flow loss at the next-stage impeller inlet, thereby improving the hydraulic performance and efficiency of the multistage pump.

Description

Technical Field

[0001] The invention relates to the technical field of fluid machinery and multistage pumps, and in particular to a high-efficiency multistage pump. Background Art

[0002] The existing multi-stage pump includes a segmented pump casing, a centrifugal impeller, a partition, a positive guide vane, and a reverse guide vane. An impeller cavity is formed between the segmented pump casing and the first side of the adjacent partition, and a centrifugal impeller is installed in the impeller cavity. A reverse guide vane cavity is formed between the second side of the partition and the next-stage segmented pump casing, and a reverse guide vane is installed in the reverse guide vane cavity. Positive guide vanes are arranged on the outer periphery of the centrifugal impeller. The segmented pump casing has a radial section, and a sealing ring is installed on the inner peripheral wall of the radial section; the centrifugal impeller includes a front disk, a rear disk, blades, an inlet ring, and a hub barrel. A plurality of blades are distributed along the circumferential direction and connected between the front disk and the rear disk. The inlet end of the front disk has an inlet ring, and the inlet ring is sealed with the sealing ring. A hub barrel is arranged on the radial inner side of the rear disk, and the hub barrel is installed on the pump shaft. The blades have blade leading edges, and the reverse guide vanes have reverse guide vane trailing edges. However, the existing matching structure between the downstream end of the reverse guide vane and the next-stage impeller still has the problems of poor sealing effect, large flow loss at the inlet of the next-stage impeller, and the efficiency of the multi-stage pump needs to be further improved. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a high-efficiency multi-stage pump, which can effectively improve the sealing effect between the reverse guide vane and the next-stage impeller, reduce the backflow and turbulence at the impeller inlet, and reduce the flow loss at the next-stage impeller inlet, thereby improving the hydraulic performance and efficiency of the multi-stage pump.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A high-efficiency multistage pump, comprising a segmented pump casing (1), a centrifugal impeller (2), a partition (3), a positive guide vane (4), and a reverse guide vane (5); an impeller cavity is formed between the segmented pump casing and a first side of an adjacent partition, a centrifugal impeller is installed in the impeller cavity, a reverse guide vane cavity is formed between the second side of the partition and the next segmented pump casing, a reverse guide vane cavity is installed in the reverse guide vane cavity, a plurality of reverse guide vanes are distributed in the circumferential direction, a positive guide vane is arranged on the outer periphery of the centrifugal impeller, a plurality of positive guide vanes are distributed in the circumferential direction, the segmented pump casing has a radial section (11), a sealing ring (12) is installed on the inner peripheral wall of the radial section; the centrifugal impeller comprises a front disc (21), a rear disc (22), blades (23), an inlet A pump comprises a ring (24), a hub (25), a plurality of blades distributed along the circumferential direction and connected between a front disk and a rear disk, an inlet ring is provided at the inlet end of the front disk, the inlet ring is sealed with a sealing ring, a hub is provided at the radial inner side of the rear disk, the hub is installed on the pump shaft, the blades have a blade leading edge (26), and the reverse guide vane has a reverse guide vane trailing edge (51); it is characterized in that: in an axial cross-sectional view passing through the axis, a sealing groove (52) is provided on the reverse guide vane (5), the upstream end of the inlet ring (24) is embedded in the sealing groove, the left side surface of the radial section (11) is used as a reference plane, the upstream end surface of the inlet ring is located on the left side of the reference plane, and the reverse guide vane trailing edge (51) is generally located on the right side of the reference plane.

[0006] Furthermore, in an axial cross-sectional view through the axis, in the radial direction, the sealing groove (52) is arranged between the sealing ring (12) and the trailing edge (51) of the anti-guide vane, the trailing edge of the anti-guide vane is arranged adjacent to the leading edge (26) of the blade, and the axial gap between the trailing edge of the anti-guide vane and the leading edge of the blade is smaller than the axial length of the inlet ring (24) and / or the sealing ring.

[0007] Furthermore, the trailing edge (51) of the anti-guide vane is tilted relative to the axis of the pump shaft, with an inclination angle a=65-85°, and the leading edge (26) of the blade is tilted relative to the axis of the pump shaft, with an inclination angle b=45-70°.

[0008] Furthermore, the maximum axial clearance between the trailing edge (51) of the anti-guide vane and the leading edge (26) of the blade is less than 0.7 times the axial length of the inlet ring (24).

[0009] Furthermore, in a radial cross-sectional view, the trailing edge (51) of the reverse guide vane presents a first corrugated structure, and the first corrugated structure extends in the radial direction.

[0010] Furthermore, the radial outer side of the first corrugated structure has a maximum curvature S1, and the radial inner side has a maximum curvature S2, S1<S2, and S1=(0.3-0.7)S2.

[0011] Furthermore, in an axial cross-sectional view passing through the axis, the blade leading edge (26) presents a second corrugated structure, and the second corrugated structure extends in the radial direction.

[0012] Furthermore, the radial outer side of the second corrugated structure has a maximum curvature S3, and the radial inner side has a maximum curvature S4, S3>S4, and S3=(1.2-2.2)S4.

[0013] Furthermore, in an axial cross-sectional view through the axis, a second inclined surface (27) is provided on the outer periphery of the left end of the hub (25), and a first inclined portion (53) is provided at the tail end of the bottom arc portion of the downstream end of the reverse guide vane (5), and the first inclined portion is substantially parallel to the second inclined surface.

[0014] A high-efficiency multistage pump of the present invention has the following beneficial technical effects:

[0015] (1) The present invention provides a sealing groove on the anti-guide vane, and the upstream end of the inlet ring is embedded in the sealing groove, so that the inlet ring and the sealing groove form an embedded rotating dynamic fit / dynamic seal; taking the left side of the radial section as the reference plane, the upstream end face of the inlet ring is located on the left side of the reference plane, and the trailing edge of the anti-guide vane is located on the right side of the reference plane, which can effectively improve the sealing effect between the anti-guide vane and the next-stage impeller, reduce the flow loss at the inlet of the next-stage impeller, and thus improve the hydraulic performance and efficiency of the multi-stage pump.

[0016] (2) The present invention can reduce backflow and turbulence at the impeller inlet by designing the trailing edge of the anti-guide vane to have a first corrugated structure (in the radial cross-sectional view) and the leading edge of the blade to have a second corrugated structure (in the axial cross-sectional view), and further reduce the flow loss at the inlet of the next-stage impeller, thereby improving the hydraulic performance and efficiency of the multi-stage pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the cross-sectional structure of a high-efficiency multi-stage pump of the present invention;

[0018] Figure 2 It is a partially enlarged structural schematic diagram of the high-efficiency multi-stage pump of the present invention;

[0019] Figure 3 It is a partially enlarged structural schematic diagram of the high-efficiency multi-stage pump of the present invention;

[0020] Figure 4 It is a schematic diagram of the trailing edge structure of the reverse guide vane of the present invention.

[0021] In the figure: a segmented pump casing 1, a centrifugal impeller 2, a partition 3, a positive guide vane / diffuser guide vane 4, a reverse guide vane 5; a radial section 11, a sealing ring 12, a front disc 21, a rear disc 22, a blade 23, an inlet ring 24, a hub 25, a blade leading edge 26, a second inclined surface 27, a reverse guide vane trailing edge 51, a sealing groove 52, and a first inclined portion 53. DETAILED DESCRIPTION

[0022] In order to make the technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described in detail in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present invention, which are only used to explain the present invention, not to limit the present invention. It should be noted that, for the convenience of description, only the parts / structures related to the present invention are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0023] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present invention should be the common meanings understood by ordinary technicians in the field to which the present invention belongs.

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0025] like Figure 1-4 As shown, a high-efficiency multistage pump comprises a segmented pump casing 1, a centrifugal impeller 2, a partition 3, a positive guide vane 4, and a reverse guide vane 5. An impeller cavity is formed between the segmented pump casing 1 and a first side of an adjacent partition 3, and a centrifugal impeller 2 is installed in the impeller cavity. A reverse guide vane cavity is formed between the second side of the partition 3 and the next segmented pump casing 1, and a reverse guide vane 5 is installed in the reverse guide vane cavity. A plurality of reverse guide vanes 5 are distributed along the circumferential direction. A positive guide vane 4 is arranged on the outer periphery of the centrifugal impeller 2. A plurality of positive guide vanes 4 are distributed along the circumferential direction. The segmented pump casing 1 has a radial section 11, and an inner periphery of the radial section 11 is provided with a plurality of positive guide vanes 4. The centrifugal impeller 2 comprises a front disc 21, a rear disc 22, blades 23, an inlet ring 24, and a hub 25. A plurality of blades 23 are distributed along the circumferential direction and connected between the front disc 21 and the rear disc 22. The inlet end of the front disc 21 has an inlet ring 24, and the inlet ring 24 is sealed with the sealing ring 12. A hub 25 is provided on the radial inner side of the rear disc 22, and the hub 25 is installed on the pump shaft. The blades 23 have a blade leading edge 26, and the reverse guide vane 5 has a reverse guide vane trailing edge 51. It is characterized in that: in the axial cross-sectional view through the axis (XX) (such as Figure 2-3 As shown in the figure, a sealing groove 52 is provided on the reverse guide vane 5, and the upstream end of the inlet ring 24 is embedded in the sealing groove 52. The left side surface of the radial section 11 is used as the reference plane, the upstream end surface of the inlet ring 24 is located on the left side of the reference plane, and the reverse guide vane trailing edge 51 is generally located on the right side of the reference plane.

[0026] A high-efficiency multistage pump of the present invention is provided with a sealing groove 52 on the anti-guide vane 5, and the upstream end of the inlet ring 24 is embedded in the sealing groove 52, so that the inlet ring 24 and the sealing groove 52 form an embedded rotating dynamic fit / seal; taking the left side surface of the radial section 11 as the reference plane, the upstream end surface of the inlet ring 24 is located on the left side of the reference plane, and the anti-guide vane trailing edge 51 is located on the right side of the reference plane, which can effectively improve the sealing effect between the anti-guide vane 5 and the next-stage impeller, reduce the flow loss at the inlet of the next-stage impeller, and thus improve the hydraulic performance and efficiency of the multistage pump.

[0027] Furthermore, in the axial cross-sectional view through the axis, as shown in FIG. Figure 2-3 As shown, in the radial direction, the sealing groove 52 is arranged between the sealing ring 12 and the anti-guide vane trailing edge 51, the anti-guide vane trailing edge 51 is arranged adjacent to the blade leading edge 26, and the axial gap between the anti-guide vane trailing edge 51 and the blade leading edge 26 is smaller than the axial length of the inlet ring 24 and / or the sealing ring 12.

[0028] Furthermore, the trailing edge 51 of the anti-guide vane is tilted relative to the pump shaft axis, with an inclination angle a=70-80°, preferably 75°; the leading edge 26 of the blade is tilted relative to the pump shaft axis (XX), with an inclination angle b=50-65°, preferably 57°.

[0029] The maximum axial clearance between the reverse guide vane trailing edge 51 and the blade leading edge 26 is less than 0.6-0.7 times the axial length of the inlet ring 24 .

[0030] In one embodiment, in a radial cross-sectional view (the radial cross-section is perpendicular to the axial cross-section), as shown in FIG. Figure 4 As shown, the trailing edge 51 of the reverse guide vane has a first corrugated structure, and the first corrugated structure extends in the radial direction.

[0031] The radial outer side of the first corrugated structure has a maximum curvature S1, and the radial inner side has a maximum curvature S2, S1<S2, and S1=(0.4-0.6)S2, preferably 0.5.

[0032] The present invention can reduce backflow and turbulence at the impeller inlet by designing the trailing edge 51 of the reverse guide vane to have a first corrugated structure (in the radial cross-sectional view), and further reduce flow losses at the inlet of the next-stage impeller, thereby improving the hydraulic performance and efficiency of the multi-stage pump.

[0033] In the axial section view through the axis (XX), Figure 2-3 As shown, the blade leading edge 26 has a second corrugated structure, and the second corrugated structure extends in the radial direction.

[0034] The radial outer side of the second corrugated structure has a maximum curvature S3, and the radial inner side has a maximum curvature S4, S3>S4, and S3=(1.3-2.0)S4, preferably 1.6-1.7.

[0035] The present invention can further reduce backflow and turbulence at the impeller inlet by designing the blade leading edge 26 to have a second corrugated structure (in the axial cross-sectional view), and further reduce flow losses at the next-stage impeller inlet, thereby improving the hydraulic performance and efficiency of the multi-stage pump.

[0036] In one embodiment, in an axial cross-sectional view through the axis, as shown in FIG. Figure 2-3 As shown, the outer periphery of the left end of the hub 25 is provided with a second inclined surface 27, and the tail end of the bottom arc portion of the downstream end of the reverse guide vane 5 is provided with a first inclined portion 53, and the first inclined portion 53 is substantially parallel to the second inclined surface 27. The present invention can further reduce the backflow and turbulence at the impeller inlet and further reduce the flow loss at the next stage impeller inlet through the design of the first inclined portion 53, thereby improving the hydraulic performance and efficiency of the multi-stage pump.

[0037] A high-efficiency multistage pump of the present invention has the following beneficial technical effects:

[0038] (1) The present invention provides a sealing groove 52 on the anti-guide vane 5, and the upstream end of the inlet ring 24 is embedded in the sealing groove 52, so that the inlet ring 24 and the sealing groove 52 form an embedded rotating dynamic fit / seal; taking the left side surface of the radial section 11 as the reference plane, the upstream end surface of the inlet ring 24 is located on the left side of the reference plane, and the anti-guide vane trailing edge 51 is located on the right side of the reference plane, which can effectively improve the sealing effect between the anti-guide vane 5 and the next-stage impeller, reduce the flow loss at the inlet of the next-stage impeller, and thus improve the hydraulic performance and efficiency of the multi-stage pump.

[0039] (2) The present invention can reduce backflow and turbulence at the impeller inlet by designing the trailing edge 51 of the reverse guide vane to have a first corrugated structure (in the radial cross-sectional view) and the leading edge 26 of the blade to have a second corrugated structure (in the axial cross-sectional view), and further reduce the flow loss at the inlet of the next-stage impeller, thereby improving the hydraulic performance and efficiency of the multi-stage pump.

[0040] The above-mentioned implementation modes are for explanation of the present invention rather than limitation of the present invention. It can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A high-efficiency multistage pump, comprising a segmented pump casing (1), a centrifugal impeller (2), a partition (3), a positive guide vane (4), and a reverse guide vane (5), wherein an impeller cavity is formed between the segmented pump casing and a first side of an adjacent partition, a centrifugal impeller is installed in the impeller cavity, a reverse guide vane cavity is formed between the second side of the partition and a segmented pump casing of a next stage, a reverse guide vane cavity is installed in the reverse guide vane cavity, a plurality of reverse guide vanes are distributed along the circumferential direction, a positive guide vane is arranged on the outer periphery of the centrifugal impeller, a plurality of positive guide vanes are distributed along the circumferential direction, and the segmented pump casing has A radial section (11) is provided, and a sealing ring (12) is installed on the inner peripheral wall of the radial section; the centrifugal impeller comprises a front disc (21), a rear disc (22), blades (23), an inlet ring (24), and a hub (25); a plurality of blades are distributed along the circumferential direction and connected between the front disc and the rear disc; an inlet ring is provided at the inlet end of the front disc, and the inlet ring is in sealing cooperation with the sealing ring; a hub is provided on the radial inner side of the rear disc, and the hub is installed on the pump shaft; the blades have blade leading edges (26), and the reverse guide vanes have reverse guide vane trailing edges (51); Features: In an axial cross-sectional view through the axis, a sealing groove (52) is provided on the reverse guide vane (5), and the upstream end of the inlet ring (24) is embedded in the sealing groove. The left side surface of the radial section (11) is used as a reference plane, the upstream end surface of the inlet ring is located on the left side of the reference plane, and the trailing edge (51) of the reverse guide vane is generally located on the right side of the reference plane. In a radial cross-sectional view, the trailing edge (51) of the reverse guide vane presents a first corrugated structure, the first corrugated structure extends radially, the radial outer side of the first corrugated structure has a maximum curvature S1, the radial inner side has a maximum curvature S2, S1<S2, and S1=(0.3-0.7)S2; In the axial cross-sectional view through the axis, the outer periphery of the left end of the hub (25) is provided with a second inclined surface (27), and the tail end of the bottom arc portion of the downstream end of the reverse guide vane (5) is provided with a first inclined portion (53), and the first inclined portion is arranged parallel to the second inclined surface.

2. A high-efficiency multistage pump as claimed in claim 1, characterized in that: In an axial cross-sectional view through the axis, in the radial direction, the sealing groove (52) is arranged between the sealing ring (12) and the trailing edge (51) of the anti-guide vane, the trailing edge of the anti-guide vane is arranged adjacent to the leading edge (26) of the blade, and the axial gap between the trailing edge of the anti-guide vane and the leading edge of the blade is smaller than the axial length of the inlet ring (24) and / or the sealing ring.

3. A high-efficiency multistage pump as claimed in claim 2, characterized in that: The trailing edge (51) of the reverse guide vane is tilted relative to the axis of the pump shaft, with an inclination angle a=65-85°, and the leading edge (26) of the blade is tilted relative to the axis of the pump shaft, with an inclination angle b=45-70°.

4. A high-efficiency multistage pump as claimed in claim 3, characterized in that: The maximum axial gap between the trailing edge (51) of the reverse guide vane and the leading edge (26) of the blade is less than 0.7 times the axial length of the inlet ring (24).

5. A high-efficiency multistage pump as claimed in claim 4, characterized in that: In an axial cross-sectional view through the axis, the blade leading edge (26) presents a second corrugated structure, which extends in the radial direction.

6. A high-efficiency multistage pump as claimed in claim 5, characterized in that: The second corrugated structure has a maximum curvature S3 on the radial outer side and a maximum curvature S4 on the radial inner side, S3>S4, and S3=(1.2-2.2)S4.

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