Two-stage open impeller partial flow pump

Abstract

The invention 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] The present invention relates to the technical field of partial flow pumps, and particularly to a two-stage open impeller partial flow pump. Background Art

[0002] At present, small-flow high-head centrifugal pumps (flow rate Q < 6 m3 / h, head H up to ~300 m) used in the petroleum and chemical industries mostly adopt straight blade open impellers. The flow angle of the liquid at the blade inlet and the blade angle differ greatly, and the impact loss between the incoming flow at the inlet and the blade inlet is very large. The liquid flow in the blade passage is not good. After reaching a certain rotational speed and head, large noise and vibration often occur, and the cavitation performance of the pump is very poor. Under the current strict environmental protection monitoring, the environmental protection requirements are often not met. Summary of the Invention

[0003] According to the defects existing in the above-mentioned prior art, it is necessary to carry out research on a new hydraulic model of a new type of blade that is more in line with fluidity, reduce the operating noise of the pump, and improve the hydraulic efficiency.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a two-stage open impeller partial flow pump, including 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 to the pump cover, and the pump cavity formed by the pump body and the pump cover is provided with a first-stage impeller, a guide vane and a second-stage impeller. The first-stage impeller and the second-stage impeller are assembled on the shaft and rotate synchronously with the shaft. The first-stage impeller and the second-stage impeller are arranged on both sides of the guide vane in the same direction. The flow passages of the first-stage impeller and the second-stage impeller are connected through the flow passage of the guide vane. Both the first-stage impeller and the second-stage impeller are open impellers. On the side of the first-stage impeller and the second-stage impeller opposite to the pump body inlet, a number of open blades are equally divided at equal angles. The number of the open blades is a backward-inclined corrugated structure. The corrugated structure forms a front wave peak protruding forward on the blade inlet part of the open blade, and the circumferential angle of the front wave peak blade gradually increases. The open blade forms a rear wave peak protruding backward on the blade outlet part, and the circumferential angle of the rear wave peak blade at the outlet does not exceed 90 degrees.

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

[0006] Further, the blade inlet setting angle of the open blade is between 20° and 32°, and the blade angle is changed in an open manner at a position one-third of the blade length from the outlet end, and smoothly transitions to the outlet. The blade outlet angle is between 75° and 90°. The corrugated structure is formed by the smooth change between the blade inlet setting angle and the blade outlet angle, which can make the liquid change the flow direction with the smallest loss in the flow passage.

[0007] Based on the above technical solution, the impeller structure of the present invention adopts backward-inclined blades to replace the commonly designed straight blades. The inlet liquid flow angle of this open blade is given according to calculations, and the blade inlet setting angle is between 20° and 32°. The design from the blade inlet to the middle and rear parts of the blade follows the blade design rules of a centrifugal pump, adopting a blade angle that coincides with the relative flow direction of the liquid, making the blade change more in line with the flow law, reducing the resistance loss during operation, improving the hydraulic efficiency, and reducing the noise and vibration under high-speed operating conditions. The blade changes the blade angle in an open manner at about one-third of the blade length at the outlet end, smoothly transitioning to the outlet. The blade outlet angle is between 75° and 90°, causing a large moment of momentum of the liquid at the impeller outlet and increasing the head of the pump.

[0008] Furthermore, the open blade includes long blades and short blades. The number of long blades and short blades is equal, and one short blade is arranged between two adjacent long blades. The short blade has a short inlet, reducing the inlet blockage and increasing the flow capacity of the impeller.

[0009] Based on the above technical solution, the design of this impeller adopts long and short blades, increasing the inlet flow area of the impeller, reducing the inlet flow velocity of the blade, reducing the flow loss, making 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 head of the pump.

[0010] Furthermore, the open impeller includes a rear cover plate, the open blade, and a central hub; the central hub is arranged 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 blade 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 along the blade to the outlet, used to support the back of the open blade. The rear cover plate cooperates with the radial flow in the open impeller flow channel to form a curved shape. The open impeller is provided with several balance holes for liquid to flow through 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 along the blade to the outlet, only supporting the back of the blade, increasing the area of the working surface of the blade. The change of the rear cover plate is designed to be in a curved shape to facilitate the radial flow in the impeller flow channel. The impeller is provided with a liquid channel similar to a balance hole on the rear cover plate on the hub side. When the back blade rotates, the pressure near the center line decreases, and the suction function can be achieved through this channel (balance hole), achieving the effect of a double-suction impeller and increasing the energy efficiency level of the pump; at the same time, the channel also has the function of a balance hole when the back pressure is high, reducing the pressure in the sealing cavity.

[0012] Furthermore, a stage interlining is arranged between the first-stage impeller and the second-stage impeller, and the stage interlining is installed in the inner hole of the guide vane.

[0013] Based on the above technical solution, a wear-resistant inter-stage bushing is provided between the primary impeller and the secondary impeller. The inter-stage bushing plays a throttling role to reduce the return loss. The primary impeller and the secondary impeller adopt open impellers to reduce the disc friction loss. The impeller clearance can be adjusted axially, which is suitable for transporting various corrosive media with low particle content.

[0014] Further, the guide vane includes a forward guide vane, a rear wear-resistant plate of the primary impeller, a backward guide vane, and a front wear-resistant plate of the secondary impeller that are axially connected in sequence along the liquid transportation direction; a plurality of forward guide vanes are evenly arranged circumferentially outside the outlet of the primary impeller and are connected to the rear wear-resistant plate of the primary impeller. A plurality of backward guide vanes are evenly arranged circumferentially between the rear wear-resistant plate of the primary impeller and the front wear-resistant plate of the secondary impeller, which plays the role of collecting the liquid flow and guiding it back to the inlet of the secondary impeller.

[0015] Further, the liquid inlet of the primary impeller is located at the center position of the primary impeller and is connected to the inlet of the pump body. The liquid outlet of the primary impeller is located at the outer edge of the blades of the primary impeller; the liquid outlet of the primary impeller is correspondingly arranged and connected to the liquid inlet of the guide vane; the liquid inlet of the guide vane is located in the adjacent space of a plurality of forward guide vanes on the outer edge of the rear wear-resistant plate of the primary impeller. The liquid outlet of the guide vane is located at the center position of a plurality of backward guide vanes. The liquid outlet of the guide vane is correspondingly arranged and connected to the liquid inlet of the secondary impeller; the liquid inlet of the secondary impeller is located at the center position of the secondary impeller. The liquid outlet of the secondary impeller is located at the outer edge of the blades of the secondary impeller and is connected to the throat outlet of the pump body. The liquid enters the liquid inlet of the primary impeller from the inlet of the pump body, passes through the primary impeller, the guide vane, and the secondary impeller in sequence, and then leaves the throat outlet of the pump body in the tangential direction of the blades of the secondary impeller.

[0016] Based on the above technical solution, the present invention provides a flow guiding component integrated with the front and rear wear-resistant plates. The surfaces of the rear wear-resistant plate of the primary impeller in contact with the primary impeller and the front wear-resistant plate of the secondary impeller in contact with the secondary impeller can be hardened to play a wear-resistant role. A plurality of guide vane blades are evenly arranged circumferentially at the position corresponding to the outlet of the primary impeller on the guide vane, which can effectively collect the liquid ejected from the impeller. Since the guide vanes are evenly arranged, the radial forces received by the impeller are also evenly arranged circumferentially and cancel each other out. Therefore, the radial force can be effectively balanced and the vibration of the pump can be reduced. Although this design uses two-stage impellers, since the primary impeller does not generate radial force, the radial force received by the entire rotor is also very small, making the two-stage impeller arrangement possible. The guide vane body is designed with a compact structure and a small axial dimension, which reduces the shaft extension length of the pump and improves the rigidity of the rotor.

[0017] Further, a cylindrical sleeve is welded to the end of the pump cover. The primary impeller, the guide vane, and the secondary impeller are assembled in the cylindrical sleeve. The guide vane is supported and fixed through the inner hole of the cylindrical sleeve. The cylindrical sleeve is arranged in 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, a partial flow pump of the present invention is horizontally installed and has a rear-pull structure, which facilitates the disassembly of the rotor components for replacement and maintenance. The pump body and the pump cover form a pressure-bearing member that 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 of a cylindrical structure. The pump cover is connected to the pump body through a flange and fasteners to form a pressure chamber. The pump cover is a welded structure. By welding a cylindrical sleeve on the conventional pump cover, the inner diameter of the cylindrical sleeve provides radial positioning for the outer circle of the guide vane, and two impellers and the guide vane are accommodated in the cylindrical sleeve and can be pulled out as a whole during installation and disassembly.

[0019] Further, one end of the pump cover away from the pump body is connected to a bearing housing, the shaft is rotatably arranged in the bearing housing, the output end of the shaft passes through the pump cover and enters the pump body, and a shaft sleeve and a seal assembly are arranged between the shaft and the pump cover.

[0020] Further, the shaft is rotatably arranged in the bearing housing through two sets of front and rear 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 axially limits the cylindrical roller bearing; the rear bearing near the drive end of the shaft 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 arranged in a bearing body. The bearing body is placed in the inner hole of the bearing housing through outer circle positioning. There is a clearance fit between the bearing body and the inner hole of the bearing housing. A flange is formed on the bearing body, and a fastening bolt and an adjusting bolt are threadedly connected to the flange. The bearing body and the bearing housing are fixedly locked by the fastening bolt, and the adjusting bolt abuts against the end face of the bearing housing, thereby controlling the distance between the flange of the bearing body and the end face of the bearing housing, adjusting the axial installation position of the rotor structure formed by the shaft, the first-stage impeller and the second-stage impeller. The outer peripheral surface of the wear-resistant plate of the guide vane is inlaid and pressed in the inner hole of the cylindrical sleeve. The guide vane is a stationary part, and when the axial installation position of the shaft changes, the position of the guide vane remains unchanged.

[0021] Based on the above technical solution, the bearing frame formed by the bearing housing and the bearing body is designed as a structure in which the rotor can be adjusted axially: the shaft is installed in the bearing housing through two sets of front and rear bearings. The front bearing is a cylindrical roller bearing that only bears radial force, and the inner and outer rings of the bearing can move axially for a short distance; the rear bearing is a pair of angular contact ball bearings placed in the bearing body. The bearing body is placed in the inner hole of the bearing housing through outer circle positioning and bears axial and radial forces. There is a clearance fit between the bearing body and the inner hole of the bearing housing. By using the fastening bolt and the adjusting bolt, the axial position of the rotor can be adjusted, and the running clearance between the impeller and the front and rear wear-resistant plates can be adjusted during operation, thereby adjusting the performance parameters of the pump.

[0022] The beneficial effects of the present invention are as follows: This pump adopts a two-stage open impeller. After the liquid is discharged from the primary impeller, it enters the guide vane. The guide vane changes the flow direction of the liquid and then enters the secondary impeller. After the work done by the secondary impeller, the liquid obtains higher energy and then leaves the pump cover and the throat outlet of the pump body in a tangential direction. The open impeller structure can reduce the disc loss. The blades adopt a backward-inclined corrugated structure. From the blade inlet to the middle and rear parts of the blade, the design is based on the blade design rules of a centrifugal pump, and the blade angle that coincides with the relative flow direction of the liquid is adopted, making the blade change more in line with the flow law, reducing the resistance loss during operation, improving the hydraulic efficiency, and reducing the noise and vibration under high-speed operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the two-stage open impeller partial-flow pump of the present invention; Figure 2 It is a sectional view of the impeller structure; Figure 3 It is a front view of the impeller structure; Figure 4 It is a sectional view of the guide vane structure; Figure 5 is Figure 4 The A-A sectional view of the guide vane in In the figure: 1. Pump body, 2. Primary impeller, 3. Intermediate bush, 4. Guide vane, 401. Positive guide vane, 402. Rear wear-resistant plate of the primary impeller, 403. Reverse guide vane, 404. Front wear-resistant plate of the secondary impeller, 5. Secondary impeller, 6. Pump cover, 7. Seal group, 8. 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 wave crest, 19. Rear wave crest, 20. Central hub, 21. Cylindrical sleeve, 22. Cylindrical roller bearing, 23. Front end cover, 24. Angular contact ball bearing; a. Inlet installation angle. DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0025] See attached Figures 1-5, Two-stage open impeller partial flow pump, including pump body 1, primary impeller 2, guide vane 4, secondary impeller 5, pump cover 6 and shaft 9; the pump body 1 is connected to the pump cover 6, and the pump cavity formed by the pump body 1 and the pump cover 6 is provided with a primary impeller 2, a guide vane 4 and a secondary impeller 5. The primary impeller 2 and the secondary impeller 5 are assembled on the shaft 9 and rotate synchronously with the shaft 9. The primary impeller 2 and the secondary impeller 5 are arranged on both sides of the guide vane 4 in the same direction. The flow channels of the primary impeller and the secondary impeller are connected through the flow channel of the guide vane. Both the primary impeller 2 and the secondary impeller 5 are open impellers. On the side of the primary impeller 2 and the secondary impeller 5 opposite to the inlet of the pump body 1, a number of open blades are equally divided at equal angles. The number of the open blades is a backward-inclined corrugated structure. The corrugated structure is that the open blade forms a front wave peak 18 protruding forward on the inlet part of the blade, and the circumferential angle of the front wave peak blade gradually increases. The open blade forms a rear wave peak protruding backward on the outlet part of the blade, and the circumferential angle of the rear wave peak blade at the outlet does not exceed 90 degrees.

[0026] Based on the above technical solution, the front side of the blade is the front along the rotation direction of the blade, and the rear side of the blade is the rear along the rotation direction of the blade. The circumferential angle of the blade is the included angle between the tangent of the blade at this point and the circumferential direction.

[0027] Further, the installation angle of the open blade at the blade inlet is between 20° and 32°. The blade changes the blade angle at a position one-third of the blade length from the outlet end, and smoothly transitions to the outlet. The blade outlet angle is between 75° and 90°. By the smooth change between the installation angle of the blade inlet and the blade outlet angle, the corrugated structure is formed, which can make the liquid change the flow direction with the least loss in the flow channel.

[0028] Based on the above technical solution, the impeller design of the usual partial flow pump generally adopts straight blades of a star-shaped impeller. The flow angle of the liquid at the blade inlet and the blade angle differ greatly, and the impact loss between the incoming flow at the inlet and the blade inlet is very large. The liquid flows poorly in the flow channel, the noise and vibration are obvious, and the cavitation performance of the pump is very poor. The impeller structure of the present invention uses backward-inclined blades to replace the straight blades of the usual design. The inlet flow angle of this open blade is given according to calculations, and the installation angle of the blade inlet is between 20° and 32°. From the blade inlet to the middle and rear parts of the blade, according to the blade design rules of the centrifugal pump, the blade angle that coincides with the relative flow direction of the liquid is adopted, making the blade change more in line with the flow law, reducing the resistance loss during operation, improving the hydraulic efficiency, and reducing the noise and vibration under high-speed operating conditions. The blade changes the blade angle at about one-third of the blade length at the outlet end and smoothly transitions to the outlet. The blade outlet angle is between 75° and 90°, so that the liquid generates a large moment of momentum at the impeller outlet, improving the head of the pump.

[0029] Furthermore, the open vane includes a long vane 14 and a short vane 15. The number of long vanes 14 and short vanes 15 is equal, and a short vane 15 is arranged between every two adjacent long vanes 14. The inlet of the short vane 15 is short, reducing the inlet blockage.

[0030] Based on the above technical solution, the impeller is designed with long and short vanes, increasing the inlet flow area of the impeller, reducing the inlet flow velocity of the vanes, reducing the flow loss, making the pressure and velocity distribution in the flow channel more reasonable, thereby improving the cavitation performance of the pump. The addition of short vanes also increases the head of the pump.

[0031] Furthermore, the open impeller includes a rear cover plate 16, the open vanes, and a central hub 20; the central hub 20 is arranged at the center of the rear cover plate 16, and several open vanes are distributed on the front surface of the rear cover plate 16 with the central hub 20 as the center. The outlet of the open vanes 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 along the vane to the outlet, which is used to support the back of the open vanes. The rear cover plate cooperates with the radial flow in the open impeller flow channel to form a curved shape. The open impeller is provided with several balance holes for liquid circulation on the rear cover plate 16 near the outer edge of the central hub.

[0032] Based on the above technical solution, the rear cover plate gradually decreases along the vane to the outlet, only supporting the back of the vane, increasing the area of the working surface of the vane. The change of the rear cover plate should be designed into a curved shape to facilitate the radial flow in the impeller flow channel. The impeller is provided with balance holes on the rear cover plate 16 on the hub side as liquid channels. When the back vanes rotate, the pressure near the center line decreases, and the suction function can be achieved through this balance hole channel, achieving the effect of a double-suction impeller and increasing the energy efficiency level of the pump; at the same time, the channel also has the function of balance holes when the back pressure is high, reducing the pressure in the sealing cavity.

[0033] Furthermore, an inter-stage bushing 3 is arranged between the primary impeller 2 and the secondary impeller 5, and the inter-stage bushing 3 is installed in the inner hole of the guide vane 4.

[0034] Based on the above technical solution, a wear-resistant inter-stage bushing 3 is arranged between the primary impeller 2 and the secondary impeller 5. The inter-stage bushing 3 plays a throttling role, reducing the return loss. The primary impeller 2 and the secondary impeller 5 adopt open impellers, reducing the disc loss. The impeller clearance can be adjusted axially, which is suitable for transporting various corrosive media with low particles.

[0035] Further, the guide vane 4 includes a front 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 second-stage impeller that are axially connected in sequence along the liquid transport direction; a plurality of front guide vanes 401 are evenly arranged circumferentially outside the outlet of the first-stage impeller and are connected to the rear wear-resistant plate 402 of the first-stage impeller. A plurality of reverse guide vanes 403 are evenly arranged circumferentially between the rear wear-resistant plate 402 of the first-stage impeller and the front wear-resistant plate 404 of the second-stage impeller, and function to collect the liquid flow and guide it back to the inlet of the second-stage impeller.

[0036] Further, the liquid inlet of the first-stage impeller 2 is located at the center position of the first-stage impeller and is connected to the inlet of the pump body 1. The liquid outlet of the first-stage impeller 2 is located at the outer edge of the blades of the first-stage impeller; the liquid outlet of the first-stage impeller 2 is correspondingly arranged and connected to the liquid inlet of the guide vane 4; the liquid inlet of the guide vane 4 is located in the adjacent space of a plurality of front guide vanes on the outer edge of the rear wear-resistant plate 402 of the first-stage impeller. The liquid outlet of the guide vane 4 is located at the center position of a plurality of reverse guide vanes 403. The liquid outlet of the guide vane 4 is correspondingly arranged and connected to the liquid inlet of the second-stage impeller 5; the liquid inlet of the second-stage impeller 5 is located at the center position of the second-stage impeller. The liquid outlet of the second-stage impeller 5 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 1. Liquid enters the liquid inlet of the first-stage impeller 2 from the inlet of the pump body 1, successively passes through the first-stage impeller 2, the guide vane 4, and the second-stage impeller 5, and then leaves the throat outlet of the pump body 1 from the tangential direction of the blades of the second-stage impeller.

[0037] Based on the above technical solution, the present invention provides a flow guiding component integrated with the front and rear wear-resistant plates. The surfaces of the rear wear-resistant plate 402 of the first-stage impeller that contact the first-stage impeller 2 and the front wear-resistant plate 404 of the second-stage impeller that contact the second-stage impeller 5 can be hardened to play a wear-resistant role. A plurality of guide vane blades are arranged evenly in the circumferential direction at the position corresponding to the outlet of the first-stage impeller 2 on the guide vane 4, which can effectively collect the liquid ejected from the impeller. Since the guide vanes are evenly arranged, the radial forces received by the impeller are also evenly arranged in the circumferential direction and cancel each other out. Therefore, the radial force can be effectively balanced, reducing the vibration of the pump. Although this design uses two-stage impellers, since the first-stage impeller does not generate radial force, the radial force received by the entire rotor is also very small, making the two-stage impeller arrangement possible. The guide vane body has a compact design structure, a small axial dimension, reduces the shaft extension length of the pump, and improves the rigidity of the rotor.

[0038] Further, a cylindrical sleeve is welded to the end of the pump cover 6. The first-stage impeller 2, the guide vane 4, and the second-stage impeller 5 are assembled in the cylindrical sleeve 21. The guide vane 4 is supported and fixed through the inner hole of the cylindrical sleeve 21. The cylindrical sleeve 21 is arranged in the pump body 1, and the outer diameter of the cylindrical sleeve 21 matches the inner diameter of the pump body 1.

[0039] Based on the above technical solution, part of the flow pump of the present invention is horizontally installed and has a rear-pull structure, which is convenient for disassembling the rotor components for replacement and maintenance. The pump body 1 and the pump cover 6 form a pressure-bearing member that 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. A pressure chamber is formed by connecting the pump cover through a flange and fasteners. The pump cover is a welded structure. By welding a cylindrical sleeve 21 on 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.

[0040] Further, one end of the pump cover 6 away from the pump body 1 is connected to a bearing housing 10. The shaft 9 is rotatably arranged in the bearing housing 10. The output end of the shaft 9 passes through the pump cover 6 and enters the pump body 1. A shaft sleeve 8 and a seal assembly 7 are arranged between the shaft 9 and the pump cover 6.

[0041] Further, the shaft 9 is rotatably arranged in the bearing housing 10 through two sets of front and rear bearings. The front bearing near the pump cover is a cylindrical roller bearing 22. A front end cover 23 is connected to the bearing housing 10, and the stop of the front end cover 23 axially positions 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 by being assembled at the shaft shoulder. The pair of angular contact ball bearings 24 are arranged in a bearing body 11. The bearing body 11 is placed in the inner hole of the bearing housing 10 through outer circle positioning. There is a clearance fit between the bearing body 11 and the inner hole of the bearing housing 10. A flange 1101 is formed on the bearing body 11. A fastening bolt 12 and an adjusting bolt 13 are threadedly connected to the flange 1101. The bearing body 11 and the bearing housing 10 are fixedly locked by the fastening bolt 12. The adjusting bolt 13 abuts against the end face of the bearing housing 10, thereby controlling the distance between the flange 1101 of the bearing body 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 primary impeller 2 and the secondary impeller 5. The outer peripheral surface of the wear-resistant plate of the guide vane is inlaid and pressed in the inner hole of the cylindrical sleeve. The guide vane is a stationary part, and when the axial installation position of the shaft changes, the position of the guide vane remains unchanged.

[0042] Based on the above technical solution, the bearing bracket formed by the bearing housing 10 and the bearing body 11 is designed as a structure where the rotor's axial position is adjustable: The shaft 9 is installed in the bearing housing 10 through two sets of front and rear bearings 22 and 24. 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 for a short distance. The rear bearing is a pair of angular contact ball bearings 24, which are placed in the bearing body 11. The bearing body 11 is placed in the bearing housing 10 through outer circle positioning and bears axial and radial forces. The inner holes of the bearing body 11 and the bearing housing 10 have a clearance fit. By using fastening bolts 12 and adjusting bolts 13, the axial position of the rotor can be adjusted, and the running clearances of the primary impeller 2, the secondary impeller 5, and the front and rear wear-resistant plates can be adjusted during operation, thereby adjusting the performance parameters of the pump. The bearing components adopt a general standard design to improve the standardization degree of the pump. This pump can select various seals that meet the API682 standard to meet the requirements of industrial pumps in various scenarios.

[0043] It should be noted that the parts not detailed in the present invention are prior art.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by 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. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0045] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plural" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0049] The above examples are only the best embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. Two-stage open impeller partial flow pump, characterized by: It comprises a pump body, a first-stage impeller, a guide vane, a secondary impeller, a pump cover and a shaft; the pump body is connected to the pump cover, and a first-stage impeller, a guide vane and a secondary impeller are arranged in a pump chamber formed by the pump body and the pump cover, the first-stage impeller and the secondary impeller are assembled on the shaft and rotate synchronously with the shaft, the first-stage impeller and the secondary impeller are arranged on both sides of the guide vane in the same direction, the flow channel of the first-stage impeller and the flow channel of the secondary impeller are connected through the flow channel of the guide vane, the first-stage impeller and the secondary impeller are both open impellers, and a plurality of open blades are evenly distributed at equal angles on one side of the first-stage impeller and the secondary impeller opposite to the pump body inlet, and the plurality of open blades are backward-inclined corrugated structures, and the corrugated structure is that the open blade forms a front wave crest protruding toward the front side at the blade inlet part, and the open blade forms a rear wave crest protruding toward the rear side at the blade outlet part.

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

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

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

5. The two-stage open impeller sectional flow pump according to any one of claims 1 to 4, characterized in that: The open impeller includes a rear cover plate, the open blades and a central hub; the central hub is arranged at the center of the rear cover plate, and a plurality of the 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; the rear cover plate does not extend to the outer diameter of the impeller, and the rear cover plate gradually decreases along the blades to the outlet, which is used to support the back of the open blades, and the rear cover plate cooperates with the radial flow in the open impeller flow channel to form a curved shape, and the open impeller is provided with a plurality of balancing holes for liquid circulation on the rear cover plate near the outer edge of the central hub.

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

7. The two-stage open impeller sectional flow pump according to any one of claims 1 to 4, characterized in that: The guide vanes include positive guide vanes, a rear wear-resistant plate of a first-stage impeller, reverse guide vanes and a front wear-resistant plate of a secondary impeller, which are axially connected in sequence along the liquid conveying direction; a plurality of positive guide vanes are evenly arranged along the circumferential direction on the outer side of the first-stage impeller outlet and connected to the rear wear-resistant plate of the first-stage impeller, and a plurality of reverse guide vanes are evenly arranged along the circumferential direction between the rear wear-resistant plate of the first-stage impeller and the front wear-resistant plate of the secondary impeller.

8. The two-stage open impeller sectional flow pump according to any one of claims 1 to 4, characterized in that: A cylindrical sleeve is welded at the end of the pump cover, the first-stage impeller, guide vanes and secondary impeller are assembled in the cylindrical sleeve, the guide vanes are supported and fixed by the inner hole of the cylindrical sleeve, the cylindrical sleeve is arranged in the pump body, and the outer diameter of the cylindrical sleeve matches the inner diameter of the pump body.

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

10. The two-stage open impeller partial flow pump according to claim 9, characterized in that: The shaft is rotatably arranged in the bearing box through two sets of front and rear bearings. The front bearing close to the pump cover is a cylindrical roller bearing. The bearing box is connected to a front end cover, and the stop of the front end cover is the axial limit of the cylindrical roller bearing; the rear bearing close to the shaft driving end is a pair of angular contact ball bearings, which are assembled at the shaft shoulder for axial positioning. The pair of angular contact ball bearings are arranged in the bearing body, and the bearing body is placed in the inner hole of the bearing box through outer circle positioning. The bearing body and the inner hole of the bearing box are clearance-matched, and a flange is formed on the bearing body, and a fastening bolt and an adjusting bolt are threadedly connected to the flange. The bearing body and the bearing box are fixed and locked by fastening bolts, and the adjusting bolt is abutted against the end face of the bearing box, thereby controlling the distance between the bearing body flange and the end face of the bearing box, and adjusting the axial installation position of the rotor structure formed by the shaft, the first-stage impeller and the secondary impeller.

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