Cast middle guide vane type high-lift multi-stage centrifugal pump
By combining the cast-shaped intermediate guide vane and the three-dimensional design flow channel, the problems of large processing volume and poor water conservancy performance in existing multi-stage centrifugal pumps are solved, and efficient and stable centrifugal pump operation is achieved.
Patent Information
- Application Number
- CN202422037773.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-22
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-08-22
AI Technical Summary
In the existing high-head multi-stage centrifugal pumps, the processing volume of the intermediate guide vane is large and it is difficult to improve water conservancy performance, resulting in an increase in the axial and radial dimensions of the pump, an increase in efficiency loss and casting difficulty, and the inability to balance the axial force, resulting in unstable operation of the equipment.
The cast-shaped intermediate guide vane is adopted to balance the front and rear pressures through a symmetrical runner design and intermediate partition design, and combine the three-dimensional design of the runner and the fluid dynamic pressure runner to reduce processing volume and improve water conservancy performance.
The cost reduction and processing volume of the intermediate guide vane are achieved, while improving the working efficiency of the centrifugal pump, balancing the axial and radial forces, and ensuring the stable operation of the equipment.
Smart Images
Figure CN222910281U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a high-lift multistage centrifugal pump, in particular to a cast intermediate guide vane type high-lift multistage centrifugal pump. Background Technique
[0002] In China, the inventory of high-lift multistage centrifugal pumps in petrochemical industry is very high. For the back-to-back type multistage centrifugal pump, an intermediate transition flow channel is required. However, most of the intermediate guide vanes of centrifugal pumps are forged and processed, which results in a large amount of processing for the intermediate guide vane and it is difficult to have good hydraulic performance. Generally, a transition flow channel with good hydraulic performance will greatly increase the axial and radial dimensions of the pump, increasing the loss of centrifugal pump efficiency and the casting difficulty. The reason for the generation of axial force in a centrifugal pump is that when the centrifugal pump is running, the front and rear covers of the impeller are asymmetric, generating a force pointing to the suction port direction. When the axial force cannot be balanced, it will cause damage to parts such as bearings and shafts. In severe cases, the equipment will not be able to operate.
[0003] To solve the above two problems, the utility model adopts a cast intermediate guide vane, which greatly reduces the product cost, reduces the processing amount and uses a three-dimensional designed flow channel to improve the hydraulic performance. Summary of the Invention
[0004] The purpose of the utility model is to provide a cast intermediate guide vane type high-lift multistage centrifugal pump. Through the symmetric flow channel design of the intermediate guide vane and the intermediate partition design in the utility model, the front and rear pressures are balanced to achieve stable operation. The casting method of the intermediate guide vane in the utility model solves the loss of efficiency and processing difficulty in the back-to-back structure, reduces the dynamic pressure of the fluid flow channel, and improves the working efficiency of the centrifugal pump.
[0005] The purpose of the utility model is realized by the following technical solutions:
[0006] A cast intermediate guide vane type high-lift multistage centrifugal pump, the centrifugal pump includes a shaft, a drive end bearing component, a drive end mechanical seal, a drive end pump cover, a suction flange, a discharge flange, a balance pipe component, a cylinder body, a middle section, a non-drive end pump cover, a bracket, a non-drive end bearing component, a drain pipe component, a non-drive mechanical seal, a balance drum, a balance disk, a final guide vane, an impeller, a guide vane, an intermediate guide vane, a suction section, a housing seal ring, an impeller seal ring; the intermediate guide vane, the mounting holes, and the hydrodynamic flow channels are integrally cast; the sum of the inlet cross-sectional areas of the hydrodynamic flow channels of the intermediate guide vane is greater than 1.5 to 1.8 times the outlet cross-sectional area of the guide vane, and an intermediate partition is provided at the five-stage flow channel; the flow channels of the intermediate guide vane are arranged in the opposite direction; the cross-sectional area of the preselected area of the intermediate guide vane is equal to the outlet cross-sectional area of the guide vane; the impellers are arranged back-to-back, and there are a total of ten stages of impellers, and the torque is transmitted by a key through the motor connecting shaft to drive the impellers to rotate; there are two sealing O-rings on the outside of the intermediate guide vane, and its installation method is to use circumferential bolts for installation. The guide vane flow channel is designed in the form of a hydrodynamic pressure discharge chamber. The pressure discharge chambers of the guide vane are divided into two groups. One group is a five-stage pressure discharge chamber, and the other group is a ten-stage pressure discharge chamber. The five-stage pressure discharge chamber is designed with an intermediate partition, and the medium flow directions of the two groups of pressure discharge chambers are arranged in the opposite direction; the impeller seal ring is installed on the impeller, the impeller and the key are installed on the shaft, the rotor shaft is integrally installed into the suction section, and the guide vane is installed thereon. The middle section is installed and fixed by screws, including the impeller, the guide vane, and the middle section are sequentially fastened and installed integrally. The final guide vane is installed and fixed on the shaft as an integral component and is axially assembled into the cylinder body; the non-drive end pump cover is set on the cylinder body and fastened with bolts, and the drive end pump cover is installed on the other side of the cylinder body.
[0007] For the described cast intermediate guide vane type high-lift multistage centrifugal pump, a drive end mechanical seal is provided on the drive end pump cover.
[0008] For the described cast intermediate guide vane type high-lift multistage centrifugal pump, a drive end bearing component is provided on the drive end pump cover.
[0009] For the described cast intermediate guide vane type high-lift multistage centrifugal pump, a bracket is provided on the non-drive end pump cover and is fastened by bolts.
[0010] For the described cast intermediate guide vane type high-lift multistage centrifugal pump, a non-drive mechanical seal is provided on the non-drive end pump cover.
[0011] For the described cast intermediate guide vane type high-lift multistage centrifugal pump, a non-drive end bearing component is provided on the non-drive end pump cover.
[0012] The advantages and effects of the present utility model are:
[0013] 1. The utility model adopts a back-to-back design of the impeller to cancel out the axial forces in two opposite directions, keeping the shaft in a tensile state, which can ensure the continuous and stable operation of the equipment.
[0014] 2. In the existing multi-stage pumps with a back-to-back design, it is very difficult to design the intermediate transition flow passage. The utility model adopts a diffuser design, with a diffuser used in the suction chamber and an intermediate diffuser used in the pressure chamber, reducing the radial and axial dimensions.
[0015] 3. In terms of hydraulic performance, the utility model uses three-dimensional design to select the flow passage design with the least loss through simulation. The medium enters the pre-whirl area before entering the flow passage, reducing the energy loss caused by impact. Then, by adding rib plates in the flow passage to offset the interaction force between the media, and dividing the flow passage into two groups, one group is a five-stage pressure flow passage and the other group is a ten-stage pressure flow passage. The liquid flow directions of the two groups of flow passages are opposite to each other, balancing the radial force with each other, reducing the vibration of the pump unit, and simultaneously balancing the axial force and the radial force.
[0016] 4. The intermediate diffuser of the utility model is cast, greatly reducing the processing cost, and the position of the flow passage is suitable for grinding after casting, increasing the smoothness of the flow passage.
[0017] 5. The utility model adopts a symmetrical impeller arrangement and uses an intermediate diffuser with good hydraulic performance, small size, small processing amount, and capable of balancing the axial force and the radial force at the same time, solving the problem that the intermediate diffuser of the back-to-back structure has a small processing amount by casting. The flow passage uses a hydrodynamic pressure flow passage, reducing the processing amount, facilitating grinding, making the flow passage more suitable for the flow of the medium, reducing losses, and increasing the efficiency of the centrifugal pump. Description of the Drawings
[0018] Figure 1 is a schematic structural diagram of the centrifugal pump of the utility model;
[0019] Figure 2 is the front view of the intermediate diffuser structure of the utility model;
[0020] Figure 3 is the left view of the intermediate diffuser structure of the utility model.
[0021] Components in the figure: shaft 1, drive-end bearing component 2, drive-end mechanical seal 3, drive-end pump cover 4, suction flange 5, discharge flange 6, balance pipe component 7, cylinder 8, middle section 9, non-drive-end pump cover 10, bracket 11, non-drive-end bearing component 12, drain pipe component 13, non-drive mechanical seal 14, balance drum 15, balance disk 16, final diffuser 17, impeller 18, diffuser 19, intermediate diffuser 20, suction section 21, housing seal ring 22, impeller seal ring 23. Detailed Description of the Preferred Embodiment
[0022] The following is a detailed description of the utility model in conjunction with the embodiments shown in the drawings.
[0023] The utility model adopts a cast intermediate guide vane, and the mounting holes and hydrodynamic flow channels are integrally cast. The sum of the inlet cross-sectional areas of the hydrodynamic flow channels of the intermediate guide vane should be 1.5 to 1.8 times larger than the outlet cross-sectional area of the guide vane. At the five-stage flow channel, an intermediate partition is provided. When the whole centrifugal pump operates, since the flow channels of the intermediate guide vane are arranged in the opposite direction, the unit is balanced and vibration is reduced. The cross-sectional area of the preselection area of the intermediate guide vane should be approximately equal to the outlet cross-sectional area of the guide vane, so that the medium flow areas before and after are large enough to reduce friction and thus improve performance. Embodiment
[0024] As Figure 1 shown, the medium of the centrifugal pump enters the suction section 21 from the suction flange 5 to guide the liquid. The impeller 18 has a total of ten stages and is driven by the motor to drive the shaft 1 to rotate. The torque is transmitted by the key to make the impeller rotate and do work on the liquid. The medium first enters the suction section of the impeller 18. After being discharged from the impeller, the medium enters the guide vane 19. The function of the guide vane is a fixed diversion part with the dual functions of a water suction chamber and a water pressure chamber, and its radial dimension is small. The medium passing through the guide vane re-enters the next-stage impeller 18 and repeats passing through the impeller 18 and the guide vane 19 five times. At this time, the medium already has the pressure of five-stage impellers, and the axial force is the same. Through the intermediate guide vane 20, through the gap between the cylinder 8 and the middle section 9, it enters the final guide vane 17, is sucked by the sixth-stage impeller 18, passes through the remaining impellers and guide vanes in turn, and returns to the intermediate guide vane 20. Since the flow channels of the intermediate guide vane do not interfere with each other, the pressure of ten stages finally enters the discharge flange to complete the work of the equipment.
[0025] The drive-end bearing component 2 mainly bears the radial force. The balance pipe component 7 is used to prevent the pressure in the seal cavity from being too high and affecting the service life of the mechanical seal, and decompresses through the balance pipe. The non-drive-end bearing component 12 is mainly used to bear the radial force and axial force. Due to the back-to-back impeller setting, the axial forces have offset each other, but there is still a small part of the force that is not balanced and is borne by the bearing. Since the pressure inside the pump is greater than that outside the pump, a drive-end mechanical seal 3 and a non-drive mechanical seal 14 are provided to prevent the liquid inside the pump from leaking out. The drain pipe component 13 is a component for discharging the remaining medium in the pump after the pump stops. The balance drum 15 is located near the final guide vane 17, rotates with the rotor, and cooperates with the balance disk 16 to balance the axial force. The housing seal ring 22 is installed on the middle section 9 and there is a gap between it and the impeller seal ring 23 to reduce the leakage between the impeller 18 and the middle section 9.
[0026] Figure 2 、 Figure 3This is the structural diagram of the intermediate guide vane 20. The main function of the intermediate guide vane is the volute chamber. Through three-dimensional design, the present utility model designs a hydrodynamic volute chamber. When the medium enters before the intermediate guide vane 20 from the guide vane 19, it first enters the pre-whirl area to reduce the pressure loss caused by the impact of the medium when it just enters the intermediate guide vane 20. The fluid can enter the flow channel after rotating 10° to 45°. The design of the flow channel reduces the energy loss caused by the fluid direction. And two sealing O-rings are added outside the intermediate guide vane 20 to reduce the circumferential leakage. The installation method adopts circumferential bolt installation. Through the casting-molded installation holes, it can be reliably installed, increasing the reliability of the unit.
[0027] The guide vane flow channel is designed as a hydrodynamic pressure outlet chamber. Through simulation analysis, the pressure loss of this form is the smallest. The pressure outlet chamber of the guide vane is divided into two groups. One group is a five-stage pressure outlet chamber, and the other group is a ten-stage pressure outlet chamber. The flow directions of the two groups of pressure outlet chambers are opposite, balancing the radial force and reducing the vibration of the pump unit. An intermediate partition is designed in the five-stage pressure outlet chamber to balance the mutual acting forces of the fluid and enable the fluid to smoothly enter through the gap between the cylinder 8 and the middle section 9, achieving the effect of reducing losses. The area of the hydrodynamic pressure outlet chamber is relatively large, which is convenient for grinding after casting, ensuring the roughness inside the flow channel and greatly improving the efficiency of the centrifugal pump.
[0028] The impeller seal ring 23 is installed on the impeller 18. The impeller 18 and the key are installed on the shaft 1. The installed rotor is axially installed into the suction section 21, the guide vane 19 is installed, and then the middle section 9 is installed by screws. In the same steps in sequence, the impeller 18, the guide vane 19, and the middle section 9 are installed in sequence, and then the intermediate guide vane 20 is installed and tightened by screws. Then the subsequent impeller 18, guide vane 19, and middle section 9 are installed in the reverse direction. Finally, the last guide vane 17 is installed. The installed components are axially installed into the cylinder 8. The non-drive end pump cover 10 is installed on the cylinder 8 and tightened with bolts. The drive end pump cover 4 is installed on the cylinder 8. The drive end mechanical seal 3 is installed on the drive end pump cover 4. The drive end bearing component 2 is installed on the drive end pump cover 4. The bracket 11 is installed on the non-drive end pump cover 10 and tightened by bolts. The non-drive mechanical seal 14 is installed on the non-drive end pump cover 10. Finally, the non-drive end bearing component 12 is installed on the non-drive end pump cover 10 to complete the installation of the centrifugal pump. After the installation of the centrifugal pump is completed, it is installed on a special base. After alignment, the motor is connected to the centrifugal pump with a coupling. The suction and discharge flanges are installed with the pipelines. The flow rate of the centrifugal pump is adjusted by adjusting the centrifugal pump outlet valve.
Claims
1. A cast intermediate guide vane high-lift multistage centrifugal pump, characterized in that: The centrifugal pump comprises a shaft (1), a drive end bearing component (2), a drive end mechanical seal (3), a drive end pump cover (4), a suction flange (5), a discharge flange (6), a balance pipe component (7), a cylinder (8), a middle section (9), a non-drive end pump cover (10), a bracket (11), a non-drive end bearing component (12), a discharge pipe component (13), a non-drive mechanical seal (14), a balance drum (15), a balance disc (16), an end guide vane (17), an impeller (18), and a guide vane (19). ), intermediate guide vanes (20), suction sections (21), casing sealing rings (22), and impeller sealing rings (23); the intermediate guide vanes, mounting holes, and fluid dynamic pressure flow channels are all integrally cast; the sum of the inlet cross-sectional areas of the intermediate guide vane fluid dynamic pressure flow channels is greater than 1.5 to 1.8 times the outlet cross-sectional areas of the guide vanes, and an intermediate partition is provided at the fifth-stage flow channel; the intermediate guide vane flow channels are oppositely arranged; the preselected area cross-sectional area of the intermediate guide vanes is equal to the outlet cross-sectional area of the guide vanes; the impellers (18) are arranged back to back, and the impellers (18) have a total of ten stages The torque is transmitted by the key through the motor connecting shaft (1) to drive the impeller (18) to rotate; two sealing O-rings are arranged on the outer side of the intermediate guide vane (20), and the installation method thereof adopts circumferential bolt installation; the guide vane flow channel is designed in the form of a fluid dynamic pressure extrusion chamber; the extrusion chamber of the guide vane is composed of two groups, one group is a five-level pressure extrusion chamber, and the other group is a 10-level pressure extrusion chamber; the five-level pressure extrusion chamber is designed with a middle partition, and the medium flow directions of the two groups of extrusion chambers are arranged in opposite directions; the impeller sealing ring (23) is installed on the impeller (18), and the impeller (18) is connected to the impeller (18). The key is mounted on the shaft (1), the rotor shaft is integrally mounted in the suction section (21), a guide vane (19) is mounted thereon, and the middle section (9) is fixed by screws, wherein the impeller (18), the guide vane (19), and the middle section (9) are sequentially fixed by screws to form an integrated assembly, and the end guide vane (17) is fixed on the shaft to form an integrated assembly, which is axially assembled into the barrel (8); the non-drive end pump cover (10) is set on the barrel (8) and fastened by bolts, and the drive end pump cover (4) is mounted on the other side of the barrel (8).
2. A cast intermediate guide vane high-lift multistage centrifugal pump according to claim 1, characterized in that: The driving end pump cover (4) is provided with a driving end mechanical seal (3).
3. The cast intermediate guide vane high-lift multistage centrifugal pump according to claim 1, characterized in that: The driving end pump cover (4) is provided with a driving end bearing component (2).
4. The cast intermediate guide vane high-lift multistage centrifugal pump according to claim 1, characterized in that: The non-drive end pump cover (10) is provided with a bracket (11) which is fastened by bolts.
5. The cast intermediate guide vane high-lift multistage centrifugal pump according to claim 1, characterized in that: A non-driving mechanical seal (14) is provided on the non-driving end pump cover (10).
6. The cast intermediate guide vane high-lift multistage centrifugal pump according to claim 1, characterized in that: The non-driving end pump cover (10) is provided with a non-driving end bearing component (12).