Two-stage open impeller partial flow pump

Abstract

The utility model relates to the technical field of partial flow pumps, in particular to a two-stage open type impeller partial flow pump which comprises a pump body, a first-stage impeller, a guide vane, a second-stage impeller, a pump cover and a shaft. The pump body is connected with the pump cover, a first-stage impeller, a guide vane and a second-stage impeller are arranged in a pump cavity formed by the pump body and the pump cover, the first-stage impeller and the second-stage impeller are assembled on the shaft and synchronously rotate along with the shaft, a flow channel of the first-stage impeller and a flow channel of the second-stage impeller are connected through a flow channel of the guide vane, and the first-stage impeller and the second-stage impeller are open type impellers. A plurality of open type blades are evenly arranged on the sides, opposite to an inlet of the pump body, of the first-stage impeller and the second-stage impeller at equal angles, the open type blades are of retroverted corrugated structures, and the corrugated structures are that the open type blades form front wave crests protruding towards the front side at the blade inlet parts, and the open type blades form rear wave crests protruding towards the rear side at the blade outlet parts. The blades are of a retroverted corrugated structure, so that the change of the blades better conforms to the flow law, and the resistance loss in the operation process is reduced.

Description

Technical Field

[0001] This utility model relates to the field of partial flow pump technology, and in particular to a two-stage open impeller partial flow pump. Background Technology

[0002] Currently, small-flow, high-lift centrifugal pumps (flow rate Q < 6 m³ / h, head H to ~300 m) used in the petroleum and chemical industries mostly employ straight-blade open impellers. The difference between the liquid flow angle at the blade inlet and the blade angle is significant, resulting in substantial impact losses between the incoming flow and the blade inlet. Poor liquid flow within the blade channels leads to frequent loud noise and vibration once a certain speed and head are reached, and the pump exhibits poor cavitation performance. Under current stringent environmental monitoring conditions, these pumps often fail to meet environmental requirements. Utility Model Content

[0003] Based on the shortcomings of the existing technology, it is necessary to conduct research on a new hydraulic model with blades that are more in line with flow characteristics, in order to reduce pump operating noise and improve hydraulic efficiency.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a two-stage open impeller partial flow pump, comprising a pump body, a first-stage impeller, guide vanes, a second-stage impeller, a pump cover, and a shaft; the pump body is connected to the pump cover, and the pump cavity formed by the pump body and the pump cover is provided with a first-stage impeller, guide vanes, and a second-stage impeller; the first-stage impeller and the second-stage impeller are mounted on the shaft and rotate synchronously with the shaft; the first-stage impeller and the second-stage impeller are arranged in the same direction on both sides of the guide vanes, and the flow channels of the first-stage impeller and the second-stage impeller are connected by the flow channels of the guide vanes. The primary and secondary impellers are both open impellers. Each impeller has several open blades at equal angles on the side opposite the pump inlet. These open blades have a backward-inclined corrugated structure. The corrugated structure consists of a forward-convex front peak at the inlet portion of the open blade, with the circumferential angle of the front peak gradually increasing. At the outlet portion, a rearward-convex back peak is formed, with the circumferential angle of the rear peak at the outlet not exceeding 90 degrees.

[0005] Based on the above technical solution, the front side of the blade is the front along the blade rotation direction, and the rear side of the blade is the rear along the blade rotation direction. The circumferential angle of the blade is the angle between the tangent at that point and the circumferential direction.

[0006] Furthermore, the inlet angle of the open blade is between 20° and 32°. The blade angle changes smoothly at one-third of the blade length from the outlet end, transitioning smoothly to the outlet. The outlet angle is between 75° and 90°. The corrugated structure is formed by the smooth change between the inlet angle and the outlet angle, which allows the liquid to change its flow direction in the flow channel with minimal loss.

[0007] Based on the above technical solution, the impeller structure of this utility model uses backward-curved blades instead of the conventionally designed straight blades. The inlet flow angle of this open blade is calculated, and the blade inlet placement angle is between 20° and 32°. The design from the blade inlet to the rear of the blade follows the blade design rules of centrifugal pumps, using a blade angle that matches the relative flow direction of the liquid. This makes the blade changes more consistent with the flow law, reducing resistance losses during operation, improving hydraulic efficiency, and reducing noise and vibration under high-speed conditions. At the outlet end, the blade angle changes openly at approximately one-third of its length, smoothly transitioning to the outlet. The blade outlet angle is between 75° and 90°, generating a larger momentum moment at the impeller outlet and increasing the pump head.

[0008] Furthermore, the open blades include long blades and short blades, with an equal number of long blades and short blades, and a short blade is disposed between two adjacent long blades. The short blades have short inlet sections, reducing inlet discharge and increasing the impeller's flow capacity.

[0009] Based on the above technical solutions, this impeller is designed with long and short blades to increase the inlet flow area of ​​the impeller, reduce the inlet velocity of the blades, reduce flow losses, and make the pressure and velocity distribution in the flow channel more reasonable, thereby improving the cavitation performance of the pump. The addition of short blades also increases the pump head.

[0010] Furthermore, the open impeller includes a rear cover plate, open blades, and a central hub; the central hub is located at the center of the rear cover plate, and several open blades are distributed on the front surface of the rear cover plate with the central hub as the center. The outlet of the open blades extends to the outer edge of the impeller; the rear cover plate does not extend to the outer diameter of the impeller, and the rear cover plate gradually decreases in size along the blades to the outlet, which is used to support the back of the open blades. The rear cover plate forms a curved shape with the radial flow in the flow channel of the open impeller. The open impeller has several balance holes for liquid flow on the rear cover plate near the outer edge of the central hub.

[0011] Based on the above technical solution, the rear cover plate gradually decreases in size from the blade to the outlet, supporting only the back of the blade, thus increasing the working surface area of ​​the blade. The change in the rear cover plate should be designed in a curved shape to facilitate radial flow within the impeller channel. The impeller has a liquid channel similar to a balance hole on the rear cover plate on the hub side. When the back blades rotate, the pressure near the centerline decreases, and suction can be achieved through this channel (balance hole), achieving the effect of a double-suction impeller and increasing the pump's energy efficiency rating. Simultaneously, the channel also acts as a balance hole when the back pressure is high, reducing the pressure in the sealed cavity.

[0012] Furthermore, an interstage bushing is provided between the first-stage impeller and the second-stage impeller, and the interstage bushing is installed in the inner hole of the guide vane.

[0013] Based on the above technical solution, a wear-resistant interstage bushing is installed between the primary and secondary impellers. The interstage bushing acts as a throttling device, reducing backflow losses. The primary and secondary impellers are open impellers, reducing disc losses. The impeller clearance can be adjusted axially, making it suitable for conveying various corrosive media with low particle content.

[0014] Furthermore, the guide vane includes a positive guide vane, a rear wear-resistant plate of the first-stage impeller, a reverse guide vane, and a front wear-resistant plate of the secondary impeller, which are connected axially in sequence along the liquid conveying direction; a number of positive guide vanes are evenly arranged on the outside of the outlet of the first-stage impeller along the circumferential direction and connected to the rear wear-resistant plate of the first-stage impeller, and a number of reverse guide vanes are evenly arranged on the circumferential direction between the rear wear-resistant plate of the first-stage impeller and the front wear-resistant plate of the secondary impeller, which serve to collect the liquid flow and guide it back to the inlet of the secondary impeller.

[0015] Furthermore, the inlet of the first-stage impeller is located at the center of the first-stage impeller and is connected to the inlet of the pump body; the outlet of the first-stage impeller is located at the outer edge of the blades of the first-stage impeller; the outlet of the first-stage impeller is correspondingly arranged and connected to the inlet of the guide vane; the inlet of the guide vane is located in the adjacent space of several positive guide vanes on the outer edge of the rear wear-resistant plate of the first-stage impeller; the outlet of the guide vane is located at the center of several negative guide vanes; the outlet of the guide vane is correspondingly arranged and connected to the inlet of the second-stage impeller; the inlet of the second-stage impeller is located at the center of the second-stage impeller; the outlet of the second-stage impeller is located at the outer edge of the blades of the second-stage impeller and is connected to the throat outlet of the pump body. The liquid enters the inlet of the first-stage impeller from the inlet of the pump body, passes through the first-stage impeller, the guide vane and the second-stage impeller in sequence, and then leaves the throat outlet of the pump body from the tangential direction of the blades of the second-stage impeller.

[0016] Based on the above technical solution, this utility model incorporates a flow guide component integrated with the front and rear wear-resistant plates. The surfaces of the rear wear-resistant plate of the first-stage impeller in contact with the first-stage impeller, and the surfaces of the front wear-resistant plate of the second-stage impeller in contact with the second-stage impeller, can be hardened to provide wear resistance. Multiple guide vanes are evenly arranged circumferentially on the guide vanes corresponding to the outlet of the first-stage impeller, effectively collecting the liquid pumped out of the impeller. Because the guide vanes are evenly arranged, the radial force on the impeller is also evenly distributed circumferentially, canceling each other out, thus effectively balancing the radial force and reducing pump vibration. Although this design uses two-stage impellers, the first-stage impeller does not generate radial force, and the radial force received by the entire rotor is also very small, making the two-stage impeller arrangement possible. The guide vane body design is compact with a small axial dimension, reducing the pump shaft extension length and improving rotor rigidity.

[0017] Furthermore, a cylindrical sleeve is welded to the end of the pump cover, and the first-stage impeller, guide vane and secondary impeller are assembled inside the cylindrical sleeve. The guide vane is supported and fixed through the inner hole of the cylindrical sleeve. The cylindrical sleeve is installed inside the pump body, and the outer diameter of the cylindrical sleeve matches the inner diameter of the pump body.

[0018] Based on the above technical solution, the partial flow pump of this utility model adopts a horizontal installation and a pull-back structure, which facilitates the disassembly of the rotor components for replacement and maintenance. The pump body and pump cover form a pressure-bearing component, which withstands the maximum working pressure of the pump. The pump body adopts an end-suction structure, and the inner wall of the pump body is a cylindrical structure. The pump cover is connected to the pump cover through flanges and fasteners to form a pressure chamber. The pump cover is a welded structure, which is formed by welding a cylindrical sleeve onto a conventional pump cover. The inner diameter of the cylindrical sleeve provides radial positioning for the outer circle of the guide vane, and the two impellers and guide vanes are accommodated in the cylindrical sleeve. It can be pulled out as a whole during installation and disassembly.

[0019] Furthermore, the end of the pump cover away from the pump body is connected to the bearing housing, the shaft is rotatably mounted in the bearing housing, the output end of the shaft passes through the pump cover and enters the pump body, and a bushing and a sealing assembly are provided between the shaft and the pump cover.

[0020] Furthermore, the shaft is rotatably mounted in a bearing housing via two sets of bearings. The front bearing near the pump cover is a cylindrical roller bearing, and a front end cover is connected to the bearing housing. The stop of the front end cover serves as an axial limit for the cylindrical roller bearing. The rear bearing near the shaft drive end is a pair of angular contact ball bearings. The angular contact ball bearings are axially positioned at the shaft shoulder. The pair of angular contact ball bearings are housed in the bearing housing, and the bearing housing is positioned within the inner hole of the bearing housing via an outer circle. The bearing housing and the inner hole of the bearing housing are clearance-fitted. A flange is formed on the bearing housing, and fastening bolts and adjusting bolts are threaded onto the flange. The bearing housing and the bearing housing are fixed and locked together by the fastening bolts, and the adjusting bolts abut against the end face of the bearing housing, thereby controlling the distance between the bearing housing flange and the end face of the bearing housing and adjusting the axial installation position of the rotor structure formed by the shaft, the first-stage impeller, and the second-stage impeller. The outer circumferential surface of the wear-resistant plate of the guide vane is embedded in the inner hole of the cylindrical sleeve and pressed tightly. The guide vane is a stationary component, and its position remains unchanged when the axial installation position of the shaft changes.

[0021] Based on the above technical solution, the bearing housing and bearing body forming the bearing bracket are designed as a structure with adjustable axial position of the rotor: the shaft is mounted in the bearing housing via two sets of bearings, front and rear. The front bearing is a cylindrical roller bearing, which only bears radial force, and its inner and outer rings can move axially a short distance. The rear bearing is a pair of angular contact ball bearings, placed in the bearing body. The bearing body is positioned in the bearing housing via its outer diameter and bears both axial and radial forces. The bearing body and the inner bore of the bearing housing are clearance fits. By tightening bolts and adjusting bolts, the axial position of the rotor can be adjusted, and the running clearance between the impeller and the front and rear wear plates can be adjusted during operation, thereby regulating the pump's performance parameters.

[0022] The beneficial effects of this utility model are as follows: This pump adopts a two-stage open impeller. After the liquid is discharged from the first-stage impeller, it enters the guide vane. The guide vane changes the direction of liquid flow and enters the second-stage impeller. After the work done by the second-stage impeller, the liquid gains higher energy and leaves the pump cover and the throat outlet of the pump body in a tangential direction. The open impeller structure can reduce disc losses. The blade adopts a backward-inclined corrugated structure. The design from the blade inlet to the middle and rear of the blade is based on the blade design rules of centrifugal pumps. The blade angle is consistent with the relative flow direction of the liquid, so that the blade change is more in line with the flow law, reducing resistance loss during operation, improving hydraulic efficiency, and reducing noise and vibration under high speed conditions. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the two-stage open impeller partial flow pump structure of this utility model;

[0024] Figure 2 This is a sectional view of the impeller structure;

[0025] Figure 3 This is a front view of the impeller structure;

[0026] Figure 4 This is a cross-sectional view of the guide vane structure;

[0027] Figure 5 for Figure 4 AA section view of the center guide vane;

[0028] In the diagram: 1. Pump body; 2. First-stage impeller; 3. Interstage bushing; 4. Guide vane; 401. Forward guide vane; 402. Rear wear-resistant plate of the first-stage impeller; 403. Reverse guide vane; 404. Front wear-resistant plate of the second-stage impeller; 5. Second-stage impeller; 6. Pump cover; 7. Sealing assembly; 8. Shaft sleeve; 9. Shaft; 10. Bearing housing; 11. Bearing body; 1101. Bearing body flange; 12. Fastening bolt; 13. Adjusting bolt; 14. Long blade; 15. Short blade; 16. Rear cover plate; 17. Balance hole; 18. Front crest; 19. Rear crest; 20. Center hub; 21. Cylindrical sleeve; 22. Cylindrical roller bearing; 23. Front cover; 24. Angular contact ball bearing.

[0029] a. Placement corner at the entrance. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0031] See appendix Figure 1-5 A two-stage open impeller partial flow pump includes a pump body 1, a first-stage impeller 2, guide vanes 4, a second-stage impeller 5, a pump cover 6, and a shaft 9. The pump body 1 is connected to the pump cover 6. The pump chamber formed by the pump body 1 and the pump cover 6 houses the first-stage impeller 2, guide vanes 4, and second-stage impeller 5. The first-stage impeller 2 and second-stage impeller 5 are mounted on the shaft 9 and rotate synchronously with the shaft 9. The first-stage impeller 2 and second-stage impeller 5 are arranged in the same direction on both sides of the guide vanes 4. The flow channels of the first-stage impeller and the second-stage impeller are connected through the flow channels of the guide vanes. Both the primary impeller 2 and the secondary impeller 5 are open impellers. Several open blades are evenly distributed on the side opposite to the inlet of the pump body 1 in both the primary impeller 2 and the secondary impeller 5. Several of the open blades have a backward-inclined corrugated structure. The corrugated structure is formed by the formation of a forward-protruding front wave peak 18 at the blade inlet, with the circumferential angle of the front wave peak blade gradually increasing. At the blade outlet, the open blade forms a rear wave peak that protrudes backward, with the circumferential angle of the rear wave peak blade at the outlet not exceeding 90 degrees.

[0032] Based on the above technical solution, the front side of the blade is the front along the blade rotation direction, and the rear side of the blade is the rear along the blade rotation direction. The circumferential angle of the blade is the angle between the tangent at that point and the circumferential direction.

[0033] Furthermore, the inlet angle of the open blade is between 20° and 32°. The blade angle changes smoothly at one-third of the blade length from the outlet end, transitioning smoothly to the outlet. The outlet angle is between 75° and 90°. The corrugated structure is formed by the smooth change between the inlet angle and the outlet angle, which allows the liquid to change its flow direction in the flow channel with minimal loss.

[0034] Based on the above technical solutions, typical partial flow pump impeller designs use straight blades in a star-shaped impeller. The difference between the liquid flow angle at the blade inlet and the blade angle is significant, resulting in substantial impact losses between the incoming flow and the blade inlet. This leads to poor liquid flow within the flow channel, noticeable noise and vibration, and poor cavitation performance. This invention replaces the conventionally designed straight blades with backward-curved blades. The inlet liquid flow angle of these open blades is calculated and is between 20° and 32°. The design from the blade inlet to the rear of the blade follows the blade design rules for centrifugal pumps, using a blade angle that matches the relative flow direction of the liquid. This makes the blade changes more consistent with the flow pattern, reducing resistance losses during operation, improving hydraulic efficiency, and lowering noise and vibration at high speeds. At the outlet end, the blade angle changes smoothly at approximately one-third of its length, with an outlet angle between 75° and 90°. This generates a larger momentum moment at the impeller outlet, increasing the pump's head.

[0035] Furthermore, the open blade includes long blades 14 and short blades 15, with an equal number of long blades 14 and short blades 15, and a short blade 15 is disposed between two adjacent long blades 14. The short blade 15 has a short inlet, reducing inlet discharge.

[0036] Based on the above technical solutions, this impeller is designed with long and short blades to increase the inlet flow area of ​​the impeller, reduce the inlet velocity of the blades, reduce flow losses, and make the pressure and velocity distribution in the flow channel more reasonable, thereby improving the cavitation performance of the pump. The addition of short blades also increases the pump head.

[0037] Furthermore, the open impeller includes a rear cover plate 16, the open blades, and a central hub 20; the central hub 20 is located at the center of the rear cover plate 16, and a plurality of the open blades are distributed on the front surface of the rear cover plate 16 with the central hub 20 as the center, and the outlet of the open blades extends to the outer edge of the impeller; the rear cover plate 16 does not extend to the outer diameter of the impeller, and the rear cover plate 16 gradually decreases in size along the blades to the outlet, which is used to support the back of the open blades. The rear cover plate forms a curved shape with the radial flow in the flow channel of the open impeller, and the open impeller has a plurality of balance holes for liquid flow on the rear cover plate 16 near the outer edge of the central hub.

[0038] Based on the above technical solution, the rear cover plate gradually decreases in size from the blade to the outlet, supporting only the back of the blade, thus increasing the working surface area of ​​the blade. The change in the rear cover plate should be designed in a curved shape to facilitate radial flow within the impeller channel. The impeller has a balance hole on the rear cover plate 16 on the hub side as a liquid passage. When the back blades rotate, the pressure near the centerline decreases, and suction can be achieved through this balance hole passage, achieving the effect of a double-suction impeller and increasing the pump's energy efficiency rating. Simultaneously, the passage also acts as a balance hole when the back pressure is high, reducing the pressure in the sealing cavity.

[0039] Furthermore, an interstage bushing 3 is provided between the first-stage impeller 2 and the second-stage impeller 5, and the interstage bushing 3 is installed in the inner hole of the guide vane 4.

[0040] Based on the above technical solution, a wear-resistant interstage bushing 3 is installed between the primary impeller 2 and the secondary impeller 5. The interstage bushing 3 acts as a throttling device, reducing backflow losses. The primary impeller 2 and the secondary impeller 5 adopt open impellers to reduce disc losses. The impeller clearance can be adjusted axially, making it suitable for conveying various corrosive media with low particle content.

[0041] Furthermore, the guide vane 4 includes a positive guide vane 401, a rear wear-resistant plate 402 of the first-stage impeller, a reverse guide vane 403, and a front wear-resistant plate 404 of the secondary impeller, which are connected axially in sequence along the liquid conveying direction. A number of positive guide vanes 401 are evenly arranged on the outside of the outlet of the first-stage impeller along the circumferential direction and connected to the rear wear-resistant plate 402 of the first-stage impeller. A number of reverse guide vanes 403 are evenly arranged on the circumferential direction between the rear wear-resistant plate 402 of the first-stage impeller and the front wear-resistant plate 404 of the secondary impeller, which serve to collect the liquid flow and guide it back to the inlet of the secondary impeller.

[0042] Furthermore, the inlet of the first-stage impeller 2 is located at the center of the first-stage impeller and is connected to the inlet of the pump body 1; the outlet of the first-stage impeller 2 is located at the outer edge of the blades of the first-stage impeller; the outlet of the first-stage impeller 2 is correspondingly arranged and connected to the inlet of the guide vane 4; the inlet of the guide vane 4 is located in the adjacent space of several positive guide vanes on the outer edge of the rear wear-resistant plate 402 of the first-stage impeller; the outlet of the guide vane 4 is located at the center of several negative guide vanes 403. The liquid outlet of the guide vane 4 is correspondingly set and connected to the liquid inlet of the secondary impeller 5; the liquid inlet of the secondary impeller 5 is located at the center of the secondary impeller, and the liquid outlet of the secondary impeller 5 is located at the outer edge of the blades of the secondary impeller and is connected to the throat outlet of the pump body 1. The liquid enters the liquid inlet of the first impeller 2 from the inlet of the pump body 1, passes through the first impeller 2, the guide vane 4 and the secondary impeller 5 in sequence, and then leaves the throat outlet of the pump body 1 from the tangential direction of the blades of the secondary impeller.

[0043] Based on the above technical solution, this utility model incorporates a flow guide component integrated with the front and rear wear-resistant plates. The surfaces of the rear wear-resistant plate 402 of the first-stage impeller in contact with the first-stage impeller 2, and the surfaces of the front wear-resistant plate 404 of the second-stage impeller in contact with the second-stage impeller 5, can be hardened to provide wear resistance. Multiple guide vanes are evenly arranged circumferentially on the guide vane 4 at the outlet position of the first-stage impeller 2, effectively collecting the liquid pumped out of the impeller. Because the guide vanes are evenly arranged, the radial force on the impeller is also evenly distributed circumferentially, canceling each other out, thus effectively balancing the radial force and reducing pump vibration. Although this design uses two-stage impellers, the first-stage impeller does not generate radial force, and the radial force received by the entire rotor is also very small, making the two-stage impeller arrangement possible. The guide vane body design is compact with a small axial dimension, reducing the pump shaft extension length and improving rotor rigidity.

[0044] Furthermore, a cylindrical sleeve is welded to the end of the pump cover 6. The first-stage impeller 2, guide vane 4 and secondary impeller 5 are assembled inside the cylindrical sleeve 21. The guide vane 4 is supported and fixed by the inner hole of the cylindrical sleeve 21. The cylindrical sleeve 21 is located inside the pump body 1, and the outer diameter of the cylindrical sleeve 21 matches the inner diameter of the pump body 1.

[0045] Based on the above technical solution, the partial flow pump of this utility model adopts a horizontal installation and a pull-back structure, which facilitates the disassembly of the rotor components for replacement and maintenance. The pump body 1 and the pump cover 6 form a pressure-bearing component, which bears the maximum working pressure of the pump. The pump body adopts an end-suction structure, and the inner wall of the pump body is a cylindrical structure. The pump cover is connected to the pump cover through flanges and fasteners to form a pressure chamber. The pump cover is a welded structure. A cylindrical sleeve 21 is welded onto a conventional pump cover. The inner diameter of the cylindrical sleeve 21 provides radial positioning for the outer circle of the guide vane 4. The two impellers 2 and 5 and the guide vane 4 are accommodated in the cylindrical sleeve 21, and can be pulled out as a whole during installation and disassembly.

[0046] Furthermore, the end of the pump cover 6 away from the pump body 1 is connected to the bearing housing 10, the shaft 9 is rotatably disposed in the bearing housing 10, the output end of the shaft 9 passes through the pump cover 6 and enters the pump body 1, and a bushing 8 and a sealing assembly 7 are disposed between the shaft 9 and the pump cover 6.

[0047] Furthermore, the shaft 9 is rotatably mounted within the bearing housing 10 via two sets of bearings. The front bearing near the pump cover is a cylindrical roller bearing 22, and a front end cover 23 is connected to the bearing housing 10. The stop of the front end cover 23 serves as an axial limit for the cylindrical roller bearing 22. The rear bearing near the shaft drive end is a pair of angular contact ball bearings 24. The angular contact ball bearings 24 are axially positioned at the shaft shoulder. The pair of angular contact ball bearings 24 are housed within the bearing body 11, which is positioned within the inner hole of the bearing housing 10 via its outer diameter. The bearing body 11 and the inner hole of the bearing housing 10 are fitted with a clearance fit. A flange 1101 is formed on the bearing body 11. Fastening bolts 12 and adjusting bolts 13 are threaded onto the flange 1101. The bearing body 11 and the bearing housing 10 are fixed and locked by the fastening bolts 12. The adjusting bolts 13 abut against the end face of the bearing housing 10, thereby controlling the distance between the bearing body flange 1101 and the end face of the bearing housing 10, and adjusting the axial installation position of the rotor structure formed by the shaft 9, the first-stage impeller 2 and the second-stage impeller 5. The outer circumferential surface of the wear-resistant plate of the guide vane is embedded in the inner hole of the cylindrical sleeve and pressed tightly. The guide vane is a stationary part. When the axial installation position of the shaft changes, the position of the guide vane remains unchanged.

[0048] Based on the above technical solution, the bearing frame formed by the bearing housing 10 and bearing body 11 is designed as a rotor axial position adjustable structure: the shaft 9 is installed in the bearing housing 10 through two sets of bearings 22 and 24, front and rear. The front bearing is a cylindrical roller bearing 22, which only bears radial force, and the inner and outer rings of the bearing can move axially a short distance; the rear bearing is a pair of angular contact ball bearings 24, placed in the bearing body 11. The bearing body 11 is positioned in the bearing housing 10 by its outer circle and bears both axial and radial forces. The bearing body 11 and the inner bore of the bearing housing 10 are clearance fit. The axial position of the rotor can be adjusted by fastening bolts 12 and adjusting bolts 13. During operation, the running clearance of the first-stage impeller 2, the second-stage impeller 5, and the front and rear wear plates can be adjusted, thereby adjusting the pump's performance parameters. The bearing components adopt a universal standard design to improve the standardization of the pump. This pump can use various seals conforming to API 682 standards to meet the requirements of industrial pumps in various applications.

[0049] It should be noted that the parts of this utility model not described in detail are existing technologies.

[0050] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0052] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0053] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0055] The above-listed embodiments are merely preferred embodiments of this utility model. Obviously, this utility model is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. A two-stage open impeller partial flow pump, characterized in that: The pump comprises a pump body, a primary impeller, guide vanes, a secondary impeller, a pump cover, and a shaft. The pump body is connected to the pump cover, and the pump cavity formed by the pump body and the pump cover contains the primary impeller, guide vanes, and secondary impeller. The primary and secondary impellers are mounted on the shaft and rotate synchronously with the shaft. The primary and secondary impellers are arranged in the same direction on both sides of the guide vanes. The flow channels of the primary and secondary impellers are connected through the flow channels of the guide vanes. Both the primary and secondary impellers are open impellers. Several open blades are evenly distributed at equal angles on the side of the primary and secondary impellers opposite to the pump body inlet. The open blades have a backward-inclined corrugated structure. The corrugated structure is characterized by a forward-protruding wave crest at the blade inlet and a backward-protruding wave crest at the blade outlet.

2. The two-stage open impeller partial flow pump according to claim 1, characterized in that: The circumferential angle of the forward-peak blade gradually increases, and the circumferential angle of the rear-peak blade at the exit does not exceed 90 degrees; the circumferential angle of the blade is the angle between the tangent at that point and the circumferential direction.

3. A two-stage open impeller partial flow pump according to claim 1, characterized in that: The inlet angle of the open blade is between 20° and 32°. The blade angle changes smoothly at one-third of the blade length from the outlet end, transitioning smoothly to the outlet. The outlet angle is between 75° and 90°. The corrugated structure is formed by the smooth change between the inlet angle and the outlet angle.

4. A two-stage open impeller partial flow pump according to claim 1, characterized in that: The open blade includes long blades and short blades, and the number of long blades and short blades is equal, with a short blade placed between two adjacent long blades.

5. A two-stage open impeller partial flow pump according to any one of claims 1-4, characterized in that: The open impeller includes a rear cover plate, open blades, and a central hub; the central hub is located at the center of the rear cover plate, and a plurality of open blades are distributed on the front surface of the rear cover plate with the central hub as the center, and the outlet of the open blades extends to the outer edge of the impeller.

6. A two-stage open impeller partial flow pump according to any one of claims 1-4, characterized in that: An interstage bushing is provided between the primary impeller and the secondary impeller, and the interstage bushing is installed in the inner hole of the guide vane.

7. A two-stage open impeller partial flow pump according to any one of claims 1-4, characterized in that: The guide vane includes a positive guide vane, a rear wear-resistant plate of the first-stage impeller, a reverse guide vane, and a front wear-resistant plate of the second-stage impeller, which are connected axially in sequence along the liquid conveying direction. A number of positive guide vanes are evenly arranged on the outside of the outlet of the first-stage impeller along the circumferential direction and connected to the rear wear-resistant plate of the first-stage impeller. A number of reverse guide vanes are evenly arranged on the circumferential direction between the rear wear-resistant plate of the first-stage impeller and the front wear-resistant plate of the second-stage impeller.

8. A two-stage open impeller partial flow pump according to any one of claims 1-4, characterized in that: The pump cover is welded to a cylindrical sleeve at its end. The first-stage impeller, guide vane, and second-stage impeller are assembled inside the cylindrical sleeve. The guide vane is supported and fixed through the inner hole of the cylindrical sleeve. The cylindrical sleeve is installed inside the pump body, and the outer diameter of the cylindrical sleeve matches the inner diameter of the pump body.

9. A two-stage open impeller partial flow pump according to any one of claims 1-4, characterized in that: The pump cover is connected to the bearing housing at the end away from the pump body. The shaft is rotatably mounted in the bearing housing. The output end of the shaft passes through the pump cover and enters the pump body. A shaft sleeve and a sealing assembly are provided between the shaft and the pump cover.

10. A two-stage open impeller partial flow pump according to claim 9, characterized in that: The shaft is rotatably mounted in a bearing housing via two sets of bearings. The front bearing, near the pump cover, is a cylindrical roller bearing, and a front end cover is connected to the bearing housing. The stop of the front end cover serves as an axial limit for the cylindrical roller bearing. The rear bearing, near the shaft drive end, is a pair of angular contact ball bearings. The angular contact ball bearings are mounted on the shaft shoulder for axial positioning. The pair of angular contact ball bearings are housed in the bearing housing, and the bearing housing is positioned within the inner hole of the bearing housing via its outer diameter. The bearing housing and the inner hole of the bearing housing have a clearance fit. A flange is formed on the bearing housing, and fastening bolts and adjusting bolts are threaded onto the flange. The bearing housing and the bearing housing are fixed and locked together by the fastening bolts, and the adjusting bolts abut against the end face of the bearing housing, thereby controlling the distance between the bearing housing flange and the end face of the bearing housing and adjusting the axial installation position of the rotor structure formed by the shaft, the first-stage impeller, and the second-stage impeller.

Images