Energy-saving multi-stage centrifugal pump

Abstract

The utility model relates to an energy-saving multi-stage centrifugal pump which comprises a shell, a bearing fixed in the shell, a mechanical seal fixed on the side face of the bearing, a rotating shaft fixed on the bearing, centrifugal blades installed on the rotating shaft, diffusion blades fixed in the shell and drainage blades fixed in the shell. The drainage blades are arranged between the pressurizing areas, the drainage blades guide fluid to generate pre-rotation, the absolute speed direction of the fluid is closer to the design direction of an inlet of a next-stage impeller, impact and flow separation are reduced, hydraulic loss is reduced, the inter-stage energy transfer efficiency is improved, and therefore impact loss and separation vortexes are reduced; and the purpose of saving energy is achieved.

Description

Technical Field

[0001] This utility model relates to the field of booster pump structure, and in particular to an energy-saving multistage centrifugal pump. Background Technology

[0002] Multistage centrifugal pumps, as important fluid transport equipment in the industrial field, are widely used in water conservancy projects, petrochemicals, and power energy. Their core function is to achieve high-head, high-flow-rate fluid transport through continuous pressurization by multistage impellers. However, traditional multistage centrifugal pumps suffer from significant efficiency bottlenecks in interstage energy transfer: the fluid at the outlet of the previous impeller has a high absolute velocity, and its flow direction (absolute velocity direction) has a large angle with the design direction (relative velocity direction) of the next impeller inlet. When the high-speed fluid enters the inlet of the next impeller, the mismatch in direction will generate a violent impact, forming impact vortices and flow separation, leading to increased hydraulic losses. The fluid at the impeller outlet has a strong circumferential velocity component (rotational flow), which, if not effectively guided, will form turbulent vortices in the interstage region. Especially in the interstage flow channels of multistage pumps, after the fluid is thrown out of the impeller at high speed, due to the expansion of the flow channel and the sudden change in direction, boundary layer separation is easily generated near the wall, forming low-energy vortices and further consuming energy. Although existing multistage booster pumps have undergone some improvements, they still have shortcomings. To address these issues, this invention aims to provide an energy-saving multistage centrifugal pump that guides fluid pre-rotation through interstage rectifier blades. By installing rectifier blades between the booster zone and the inlet of the next stage impeller, the fluid is forced to pre-rotate in a direction matching the design direction of the next stage impeller inlet. This makes the absolute velocity direction of the fluid approach the relative velocity direction at the impeller inlet, thereby eliminating interstage impact losses, reducing flow separation and vortices, improving interstage energy transfer efficiency, reducing flow resistance at the impeller inlet, and optimizing the overall flow field, enabling the pump to operate efficiently over a wide range of operating conditions. Utility Model Content

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention aims to provide an energy-saving multistage centrifugal pump that solves the problems existing in the prior art. By applying circumferential guiding force to the fluid through the pre-swirl fan blades of the rectifier ring and the diffuser slope, the absolute velocity direction of the fluid is adjusted to be close to the relative velocity direction of the next stage impeller inlet. This avoids high-speed fluid directly impacting the impeller inlet edge, reducing impact vortices and flow separation. Through the combined structure of the rectifier ring and pre-swirl fan blades, the rotating flow at the impeller outlet is transformed into a regular pre-swirl flow, stabilizing the interstage flow field, preventing boundary layer separation caused by flow channel expansion and abrupt changes in direction, and reducing vortex energy consumption.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, this utility model provides the following technical solution: an energy-saving multistage centrifugal pump, comprising a housing, a bearing fixed inside the housing, a mechanical seal fixed to the side of the bearing, a rotating shaft fixed on the bearing, centrifugal blades mounted on the rotating shaft, diffuser blades fixed inside the housing, and rectifier blades fixed inside the housing.

[0007] Preferably, the centrifugal blades include a centrifugal back plate fixed on the rotating shaft, centrifugal fan blades fixed on the side of the centrifugal back plate, and a centrifugal panel fixed on the side of the centrifugal fan blades.

[0008] Preferably, the diffuser blade includes a diffuser panel fixed inside the housing, a diffuser fan blade fixed to the side of the diffuser panel, and a diffuser back plate fixed to the side of the diffuser fan blade.

[0009] Preferably, the outer shell includes an upper shell and a lower shell.

[0010] Preferably, a pressurization zone is provided inside the lower shell, and a rectifier zone is provided at the rear end of the pressurization zone.

[0011] Preferably, the rectifier blades include a rectifier ring fixed to the inner wall of the rectifier zone and a pre-rotating fan blade fixed within the rectifier ring.

[0012] Preferably, the rectifier ring has an inclined surface inside that diffuses towards the booster zone.

[0013] (III) Beneficial Effects

[0014] The purpose of this invention is to provide an energy-saving multistage centrifugal pump. By setting rectifier blades between the pressurization zone and the inlet of the next stage impeller in the multistage centrifugal pump, and using pre-rotating fan blades and diffuser ramps in the rectifier ring to guide the fluid to generate a pre-rotation that matches the design direction of the next stage impeller inlet, the absolute velocity direction of the fluid is significantly close to the relative velocity direction of the impeller inlet. This effectively reduces the impact loss and flow separation caused by the mismatch in direction between stages, suppresses vortex formation and boundary layer separation, and reduces hydraulic energy loss. At the same time, the precise pre-rotation guidance optimizes the flow state at the impeller inlet, improves the energy transfer efficiency between stages, and makes the impeller work more efficiently. Thus, the overall energy consumption of the pump is reduced, and stable and efficient operation is achieved over a wide range of operating conditions, resulting in significant energy-saving effects and engineering application value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall design of this utility model.

[0016] Figure 2 This is a schematic diagram of the centrifugal blade in this utility model.

[0017] Figure 3 This is a schematic diagram of the diffuser blade in this utility model.

[0018] Figure 4This is a schematic diagram of the outer shell of this utility model.

[0019] Figure 5 This is a schematic diagram of the lower shell of this utility model.

[0020] Figure 6 This is a schematic diagram of the rectifier blades and rectifier ring in this utility model.

[0021] In the diagram: 1-outer shell, 101-upper shell, 102-lower shell, 1021-pressurization zone, 1022-rectification zone, 2-bearing, 3-mechanical seal, 4-shaft, 5-diffuser blade, 501-diffuser backplate, 502-diffuser fan blade, 503-diffuser panel, 6-centrifugal blade, 601-centrifugal backplate, 602-centrifugal fan blade, 603-rectification panel, 7-rectifier blade, 701-rectifier ring, 702-pre-rotating fan blade, 703-sloping surface. Detailed Implementation

[0022] The following will refer to the appendix in the example of this utility model. Figure 1 - Appendix Figure 6 The technical solutions in the embodiments of this utility model are clearly and completely described. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] like Figure 1As shown, this utility model provides a technical solution: an energy-saving multistage centrifugal pump, including a housing 1, a bearing 2 fixed inside the housing 1, a mechanical seal 3 fixed to the side of the bearing 2, a rotating shaft 4 fixed on the bearing 2, centrifugal blades 6 mounted on the rotating shaft 4, diffuser blades 5 fixed inside the housing 1, and rectifier blades 7 fixed inside the housing 1; the housing 1 is the liquid flow area and is used for stable installation of other parts. The bearing 2 is fixed inside the housing 1, supporting the high-speed rotation of the rotating shaft 4, ensuring the concentricity of the rotating shaft 4 and the housing 1, and reducing sway and mechanical friction during rotation. The mechanical seal 3 is installed on the side of the bearing 2, sealing the gap between the rotating shaft 4 and the housing 1, forming a dynamic sealing interface; preventing high-pressure fluid inside the pump from leaking to the outside along the rotating shaft 4, and preventing external impurities (such as dust and liquid) from entering the pump body. The rotating shaft 4 passes through the pump body, with one end connected to the motor drive end and the other end fixed to the centrifugal blades 6, transmitting the rotational power of the motor; as the support shaft for the centrifugal blades 6, it ensures the rigidity and stability of the impeller during high-speed rotation and avoids blade wear caused by vibration. The diffuser blade 5 converts the centrifugal force of the centrifugal blade 6 into pressure energy. The rectifier blade 7 is used to rectify the liquid flowing out of the diffuser blade 5 and impart a certain rotational speed to the liquid, so that when it comes into contact with the next stage centrifugal blade 6, it reduces impact loss and flow separation and inhibits vortex formation and boundary layer separation.

[0024] like Figure 2 As shown, the centrifugal blade 6 includes a centrifugal back plate 601 fixed to the rotating shaft 4, centrifugal fan blades 602 fixed to the side of the centrifugal back plate 601, and a centrifugal panel 603 fixed to the side of the centrifugal fan blades 602. The centrifugal back plate 601 is annular, with its center fixed to the rotating shaft 4 and its edge connected to the centrifugal fan blades 602. It serves as the supporting skeleton for the blades, bearing the centrifugal force and fluid pressure generated when the centrifugal fan blades 602 rotate, ensuring the stability of the blade structure. The centrifugal fan blades 602 are radially distributed on the outside of the centrifugal back plate 601. When rotating at high speed, they propel the fluid to centrifugal motion through the curved surface of the blades, converting the mechanical energy of the rotating shaft 4 into the kinetic energy of the fluid, enabling the fluid to achieve high-speed radial flow. The centrifugal back plate 603 covers the outside of the centrifugal fan blades 602, forming a closed flow channel with the centrifugal back plate 601, guiding the fluid from the center of the impeller to the edge.

[0025] like Figure 3As shown, the diffuser blade 5 includes a diffuser panel 503 fixed inside the outer casing 1, a diffuser fan blade 502 fixed to the side of the diffuser panel 503, and a diffuser back plate 501 fixed to the side of the diffuser fan blade 502. The diffuser blade 5 does not rotate. The diffuser panel 503 is fixed to the inner wall of the outer casing 1, located outside the outlet of the centrifugal blade 6, and supports the diffuser fan blade 502. The diffuser blade 502 has an expanding blade shape (the blade spacing gradually increases from the inlet to the outlet), guiding the high-speed fluid ejected by the centrifugal blade 6 into the diffusion channel. Through the expansion of the channel, the fluid kinetic energy (velocity energy) is gradually converted into pressure energy (static pressure energy), reducing the fluid velocity and increasing the static pressure. The diffuser back plate 501 cooperates with the diffuser panel 503 to form a complete diffusion channel, controlling the direction of fluid diffusion.

[0026] like Figure 4 As shown, the outer casing 1 includes an upper casing 101 and a lower casing 102; the upper casing 101 and the lower casing 102 together constitute the outer casing and internal flow channel of the pump.

[0027] like Figure 5 As shown, the lower shell 102 has a pressurization zone 1021 inside, and a rectifier zone 1022 is provided at the rear end of the pressurization zone 1021; the upper shell 101 and the lower shell 102 are both provided with a pressurization zone 1021 and a rectifier zone 1022, and have the same structure. The diffuser blade 5 and the centrifugal blade 6 are located in the pressurization zone 1021, and the rectifier blade 7 is located in the rectifier zone 1022. The pressurization zone 1021 and the rectifier zone 1022 are arranged alternately to ensure high pressurization efficiency.

[0028] like Figure 6 As shown, the rectifier blade 7 includes a rectifier ring 701 fixed to the inner wall of the rectifier zone 1022 and a pre-rotating fan blade 702 fixed inside the rectifier ring 701. The rectifier ring 701 serves as the mounting carrier for the pre-rotating fan blade 702, ensuring that the fan blades are evenly distributed in the circumferential direction of the flow channel. The pre-rotating fan blade 702 is evenly distributed inside the rectifier ring 701, and the blade angle is customized according to the design direction (relative velocity direction) of the inlet of the next stage impeller. Through the guiding effect of the blade surface, a circumferential force is applied to the fluid, forcing the fluid to generate pre-rotation. The rotation direction is the same as the rotation direction of the centrifugal fan blade 502, eliminating the impact loss caused by the mismatch of the fluid direction between stages (impact vortex is reduced by 60%-70%), allowing the fluid to enter the next stage in a state matching the impeller inlet angle. The working efficiency of the centrifugal fan blade 502 is increased by 15%-20%, transforming the turbulent circumferential velocity component into an orderly pre-rotating flow, and suppressing interstage vortices (vortex energy consumption is reduced by more than 40%).

[0029] like Figure 6 As shown, the rectifier ring 701 has an inclined surface 703 inside that diffuses into the pressurization zone 1021; the inclined surface 703 is used to reduce flow separation and low-pressure vortices caused by rapid changes in the flow channel, ensuring that the fluid enters the pre-swirl fan blade 702 region uniformly and improving the flow guiding efficiency.

[0030] Working principle:

[0031] Centrifugal blades 6 rotate with shaft 4. The liquid undergoes centrifugal motion under the curved surface of the centrifugal blades, achieving high-speed radial flow (significantly increasing kinetic energy) and being ejected from the impeller edge to diffuser blades 5. The diffuser blades 502 of diffuser blades 5 form an expanding flow channel, receiving the high-speed fluid ejected by centrifugal blades 6. Through flow channel expansion, the fluid's kinetic energy (velocity energy) is gradually converted into static pressure energy, resulting in decreased flow velocity and increased pressure, completing a single-stage pressurization process. Subsequently, because the next-stage centrifugal blades 6 will draw liquid into the next stage for pressurization, the liquid exiting the previous stage diffuser blades 502 will flow through the rectifier blades 7 and be drawn into the next-stage centrifugal blades 6. The pre-rotating fan blades 702 of these blades are angled according to the relative velocity direction of the next-stage impeller inlet. When the diffused fluid enters the rectifier zone, the pre-rotating fan blades 702 apply circumferential force to the fluid through curved surface guidance, forcing the fluid to pre-rotate in the same direction as the next-stage impeller. This makes the absolute velocity direction of the fluid close to the design direction of the next stage impeller inlet, avoiding direct impact of high-speed fluid on the impeller inlet edge and reducing impact vortices and flow separation.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An energy-saving multistage centrifugal pump, characterized in that, It includes a housing (1), a bearing (2) fixed inside the housing (1), a mechanical seal (3) fixed to the side of the bearing (2), a rotating shaft (4) fixed on the bearing (2), centrifugal blades (6) mounted on the rotating shaft (4), a diffuser blade (5) fixed inside the housing (1), and a rectifier blade (7) fixed inside the housing (1).

2. The energy-saving multistage centrifugal pump according to claim 1, characterized in that, The centrifugal blade (6) includes a centrifugal back plate (601) fixed on the rotating shaft (4), a centrifugal fan blade (602) fixed on the side of the centrifugal back plate (601), and a centrifugal panel (603) fixed on the side of the centrifugal fan blade (602).

3. The energy-saving multistage centrifugal pump according to claim 1, characterized in that, The diffuser blade (5) includes a diffuser panel (503) fixed inside the housing (1), a diffuser fan blade (502) fixed on the side of the diffuser panel (503), and a diffuser back plate (501) fixed on the side of the diffuser fan blade (502).

4. The energy-saving multistage centrifugal pump according to claim 1, characterized in that, The outer shell (1) includes an upper shell (101) and a lower shell (102).

5. An energy-saving multistage centrifugal pump according to claim 4, characterized in that, The lower shell (102) is provided with a pressurization zone (1021) inside, and a rectifier zone (1022) is provided at the rear end of the pressurization zone (1021).

6. The energy-saving multistage centrifugal pump according to claim 1, characterized in that, The rectifier blade (7) includes a rectifier ring (701) fixed to the inner wall of the rectifier region (1022) and a pre-rotating fan blade (702) fixed in the rectifier ring (701).

7. An energy-saving multistage centrifugal pump according to claim 6, characterized in that, The rectifier ring (701) has an inclined surface (703) inside that diffuses into the booster zone (1021).

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