Multi-stage pump guide vane structure

Abstract

The utility model relates to a multistage pump guide vane structure which comprises a guide vane, the guide vane comprises a connecting base ring, the connecting base ring is connected with an annular base plate extending outwards in the radial direction, a plurality of reverse guide vanes inclining in the same direction are arranged on one face of the annular base plate in a protruding mode, and all the reverse guide vanes are arranged at intervals in the circumferential direction. The inner end of at least one reverse guide blade extends inwards to the connecting base ring and continues to vertically extend in the direction away from the annular base plate to form a protruding section so that the reverse guide blade can extend into a water inlet of a lower-stage impeller through the protruding section. In the structure, the tail ends of the two reverse guide blades are extended and bent to extend to the water inlet of the next-stage impeller, so that the flow state of the water inlet of the next-stage impeller can be controlled, and the backflow loss of the water inlet of the next-stage impeller under a small-flow working condition is weakened. Experiments show that the guide vane can improve the lift of a small flow interval, does not influence the lift of a rated working condition, can be used for improving the hump characteristic of a multi-stage pump, can also be used for debugging the slope of a lift curve with special requirements, and has practical value.

Description

Technical Field

[0001] The utility model belongs to the technical field of centrifugal pumps in non-variable displacement pumps, and particularly relates to a guide vane structure of a multi-stage pump. Background Art

[0002] Centrifugal pumps include single-stage centrifugal pumps and multi-stage centrifugal pumps, such as the technical solutions disclosed in CN210599573U and CN108757477A. An impeller and a guide vane are installed and used in cooperation in the water pressure chamber of the centrifugal pump, and are usually composed of one or more pairs of impellers and guide vanes connected in series; the impeller rotates and is arranged in the pump casing, and the guide vane is fixedly arranged in the pump casing; the impeller has a water inlet and a water outlet. During operation, the fluid at the water outlet of the impeller is guided by the guide vane to the water outlet channel of the pump (single-stage) or enters the water inlet of the next-stage impeller (multi-stage), and the guide vane is beneficial to the flow of the fluid. Several anti-guide vanes that are inclined in the same direction are usually convexly provided on the guide vane. Referring to the full-lift centrifugal pump disclosed in CN202417951U, by optimizing the outlet installation angle of the anti-guide vanes, the performance of the pump can be improved, and it can be reliably used under the conditions of high lift and small flow rate and low lift and large flow rate, and has the full-lift characteristic. However, in experimental observations and actual detections, when the flow rate is small, the fluid flow state at the impeller inlet is not good, there is a reflux loss, which affects the lift in the small flow rate range, and it can be further improved and optimized. Summary of the Invention

[0003] Aiming at the above deficiencies of the prior art, the technical problem to be solved by the utility model is to provide a guide vane structure of a multi-stage pump to avoid the problem that there is a reflux loss at the inlet of the lower-stage impeller when the multi-stage centrifugal pump is in a small flow rate condition, which affects the lift in the small flow rate range.

[0004] To solve the above technical problem, the utility model adopts the following technical scheme:

[0005] A guide vane structure of a multi-stage pump includes a guide vane. The guide vane includes a connecting base ring, the connecting base ring is connected to a radially extending annular substrate, and a plurality of anti-guide vanes that are inclined in the same direction are convexly provided on one surface of the annular substrate. All the anti-guide vanes are circumferentially spaced; the inner end of at least one anti-guide vane extends inward to the connecting base ring and continues to vertically extend in a direction away from the annular substrate to form a convex section, so as to extend into the water inlet of the lower-stage impeller through the convex section.

[0006] To further improve the above technical scheme, all the anti-guide vanes are circumferentially evenly distributed, and the inner ends of two opposite anti-guide vanes extend to have the convex section.

[0007] Furthermore, the connecting base ring, the annular substrate and each anti-guide vane are an integrally formed structure.

[0008] Further, the number of guide vanes is several, and they are arranged in series in the pump casing in one-to-one cooperation with several impellers. The impeller includes a front cover plate and a rear cover plate. The annular base plate of the guide vane cooperating therewith is located outside the rear cover plate. The side of the annular base plate provided with the return guide vanes faces the next-stage impeller. The return guide vanes on the annular base plate extend towards the next-stage impeller, and the free end of the raised section of the return guide vane with the raised section extends into the water inlet of the next-stage impeller.

[0009] Compared with the prior art, the utility model has the following beneficial effects:

[0010] In the multi-stage pump guide vane structure of the utility model, the tails of the two return guide vanes are extended and bent to extend into the water inlet of the next-stage impeller, which can control the flow state of the water inlet of the next-stage impeller and weaken the return loss at the water inlet of the next-stage impeller under the small flow condition.

[0011] Experiments show that the guide vane can increase the head in the small flow range, and at the same time does not affect the head under the rated condition. It can be used to improve the hump characteristic of the multi-stage pump, and can also be used to debug the slope of the head curve with special requirements, which has practical value. Description of the Drawings

[0012] Figure 1 is a schematic structural diagram of a conventional guide vane;

[0013] Figure 2 is Figure 1 the left view of

[0014] Figure 3 is a schematic diagram of the guide vane of a multi-stage pump guide vane structure of a specific embodiment;

[0015] Figure 4 is Figure 3 the left view of

[0016] Figure 5 is a schematic installation diagram (radial half side) of a multi-stage pump guide vane structure of a specific embodiment;

[0017] Figure 6 is a comparison diagram of the use effects of a multi-stage pump guide vane structure of a specific embodiment and a conventional guide vane;

[0018] Among them, guide vane 1, connecting base ring 11, annular base plate 12, return guide vane 13, raised section 14, pump casing 2, impeller 3, front cover plate 31, rear cover plate 32, shaft sleeve body 33, water inlet 34. Detailed Embodiments

[0019] The following further elaborates on the detailed embodiments of the present utility model with reference to the drawings.

[0020] Please refer to Figure 1 and Figure 2 , which are conventional guide vanes.Figure 3 and Figure 4 As shown in Figure 4 , the guide vane 1 in the guide vane structure of a multi-stage pump in a specific embodiment is shown. The guide vane 1 includes a connecting base ring 11, which is used to be sleeved outside the impeller. The length can be long or short, depending on the length of the cooperation with the impeller. The connecting base ring 11 is connected to a radially extending annular substrate 12. On one surface of the annular substrate 12, a plurality of anti-guide vanes 13 that are inclined in the same direction are convexly provided. The inclination direction of the anti-guide vanes 13 is adapted to the working rotation direction of the impeller, radially extending and inclined, and having a certain outward convex arc. All the anti-guide vanes 13 are circumferentially spaced; the inner end of at least one anti-guide vane 13 extends inward to the connecting base ring 11 and continues to bend and vertically extend in a direction away from the annular substrate 12 to form a convex section 14, so as to extend into the water inlet of the lower-stage impeller through the convex section 14. During implementation, the connecting base ring 11, the annular substrate 12, and each anti-guide vane 13 are an integrally formed structure and can be formed by casting or other means. The convex section 14 is still coplanar with the anti-guide vane 13 where it is located.

[0021] Preferably, all the anti-guide vanes 13 are circumferentially evenly arranged, and the inner ends of two opposite anti-guide vanes 13 extend to have the convex section 14, and the other anti-guide vanes 13 maintain a conventional shape. If the number of anti-guide vanes 13 is an even number, such as Figure 4 the eight shown in Figure 4 , then the two completely opposite anti-guide vanes 13 have the convex section 14; if the number of anti-guide vanes 13 is an odd number, such as seven, one anti-guide vane 13 and any one of the two anti-guide vanes opposite to it can be selected to have the convex section 14.

[0022] Please refer to Figure 5 , when installed on a multi-stage centrifugal pump, the number of guide vanes 1 is several, and they are arranged in series in one-to-one cooperation with several impellers 3 in the pump casing 2. The impellers 3 are synchronously rotationally connected to a pump shaft (not shown in the figure). The pump shaft rotates through the pump casing 2. The guide vane 1 is fixed relative to the pump casing 2, generally fixed by a detent pin (not shown in the figure); the impeller 3 includes a front cover plate 31 and a rear cover plate 32. The blades are connected between the front cover plate 31 and the rear cover plate 32. The rear cover plate 32 is integrally connected to the sleeve body 33 of the impeller 3 sleeving the pump shaft. The annular substrate 12 of the guide vane 1 cooperating with the impeller 3 is located outside the rear cover plate 32 and is sleeved on the sleeve section of the impeller 3 through the connecting base ring 11. Radially, there is a notch on the outer edge of the annular substrate 12 or there is a spacing between the corresponding inner wall of the pressure water chamber of the pump casing 2 to communicate the upper-stage outlet water and the lower-stage inlet water. The surface of the annular substrate 12 where the anti-guide vanes 13 are provided faces the lower-stage impeller 3. Each anti-guide vane 13 on the annular substrate 12 extends axially perpendicular to the annular substrate 12 in the direction of the lower-stage impeller. The free end of the axial extension abuts against the inner wall of the pressure water chamber of the pump casing 2. The free end of the convex section 14 of the anti-guide vane 13 having the convex section 14 extends into the water inlet 34 of the lower-stage impeller 3.

[0023] The multi-stage pump diffuser structure of the embodiment has the trailing ends of two return guide vanes 13 extended and bent to extend to the water inlet of the next-stage impeller, which can control the flow pattern at the water inlet of the next-stage impeller and weaken the return loss at the water inlet of the next-stage impeller under small-flow conditions. Experiments show that this diffuser can increase the head in the small-flow range without affecting the head under rated conditions, can be used to improve the hump characteristics of multi-stage pumps, and can also be used to adjust the slope of the head curve with special requirements.

[0024] Verification example: On a certain model test pump, a conventional original diffuser and a new diffuser of the structure of the present invention are used respectively. Among them, the length of the protruding section 14 of the new diffuser extending into the impeller water inlet 34 is about one-half of the straight section of the impeller water inlet 34. Radially, there are gaps of about 5 mm on one side between the outer and inner sides ( Figure 5 the upper and lower edges shown) of the free end of the protruding section 14 and the inner wall of the corresponding impeller water inlet 34. Please refer to Figure 6 . In the large-flow range, the head of the new diffuser basically coincides with that of the original diffuser. In the small-flow range, the head of the new diffuser increases. The head increases by about 14 m at a head of 100 m 3 / h, the slope of the head curve increases from 1.13 to 1.15, and the hump high point shifts left from 200 m 3 / h to 180 m 3 / h, and the hump is improved. The efficiency of the new diffuser decreases slightly, and it decreases by about 0.5% at a rated condition of 350 m 3 / h, which has little impact.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A multi-stage pump diffuser structure, comprising a diffuser, the diffuser including a connecting base ring, the connecting base ring connecting a radially extending annular substrate, and a plurality of counter-guide vanes protruding and inclined in the same direction are provided on one surface of the annular substrate, and all the counter-guide vanes are circumferentially spaced apart; characterized in that: The inner ends of at least one anti-guide vane extend inwards to connect to the base ring, and continue to extend vertically away from the annular substrate to form a raised section, so as to extend into the water inlet of the lower-stage impeller through the raised section.

2. The multi-stage pump diffuser structure according to claim 1, wherein: All the anti-guide vanes are circumferentially evenly distributed, and the inner ends of two opposite anti-guide vanes extend to have the raised section.

3. The multi-stage pump guide vane structure according to claim 1, characterized in that: The connecting base ring, the annular substrate and each anti-guide vane are of an integrally formed structure.

4. The multi-stage pump guide vane structure according to any one of claims 1-3, characterized in that: The number of guide vanes is several, and they are arranged in series in one-to-one cooperation with several impellers in the pump casing. The impeller includes a front cover plate and a rear cover plate. The annular substrate of the guide vane cooperating therewith is located outside the rear cover plate. The side of the annular substrate provided with the anti-guide vanes faces the lower-stage impeller. The anti-guide vanes on the annular substrate extend towards the lower-stage impeller, and the free end of the raised section of the anti-guide vane with the raised section extends into the water inlet of the lower-stage impeller.

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