Shielded multistage pump

Abstract

The application relates to the technical field of canned pumps, in particular to a canned multistage pump which comprises a conveying section and a power section arranged in sequence along an axial direction, a flow regulating assembly is arranged at the medium inlet of the conveying section; a stator assembly and a rotor assembly constituting electromagnetic induction cooperation are fixed in the power section, a driving shaft is coaxially fixed with the rotor assembly; a thrust disc is coaxially fixed on the driving shaft and cooperates with the bearing of the driving shaft; a guide groove is arranged on the working surface of the thrust disc in the radial direction, at least three groups of floating tiles are assembled in the guide groove, at least one fulcrum abutting against the groove bottom surface of the guide groove is arranged on the floating tile, so that the floating tile can produce pitching movement in the guide groove along the radial direction of the thrust disc around the fulcrum, and the end surface of the floating tile away from the guide groove forms surface contact with the bearing. The application greatly reduces the abrasion degree of the bearing used in cooperation with the thrust disc in the canned pump, and improves the performance of the canned pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of canned pump, in particular to a canned multi-stage pump. BACKGROUND

[0002] The canned multi-stage pump is an important equipment in the fields of chemical industry, petrochemical industry, chemical fiber, pharmaceutical, refrigeration and nuclear power, and is a combination of centrifugal pump and canned motor. The rotor and impeller of the canned multi-stage pump are fixed on the same shaft, the rotor and stator are separated by a shield, the rotor rotates in the medium to be transported, and the power is transmitted to the rotor through the stator magnetic field, and then transmitted to the impeller of the canned pump.

[0003] The canned multi-stage pump is generally suitable for use in large flow and high lift working conditions. The axial force of the water pump is large, and in particular, the axial force of the vertical multi-stage pump also includes the weight of the rotor assembly and the plurality of impellers. The axial force is larger than that of the horizontal pump. During operation, the excessive axial force can greatly aggravate the wear of the bearing in the pump body, resulting in reduced performance of the water pump. At the same time, under the operating condition of large flow, the medium entering the canned pump will cause uneven distribution of the medium, resulting in uneven stress of the impeller along the radial direction. Influenced by the impeller, the driving shaft of the canned pump will be eccentric, resulting in line contact or point contact between the bearing on the driving shaft and the thrust disc in the pump body, further increasing the wear of the bearing. Therefore, it is urgent to solve. SUMMARY

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present application provides a canned multi-stage pump. The present application greatly reduces the wear degree of the bearing used in cooperation with the thrust disc in the canned pump, and improves the performance of the canned pump.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] A canned multi-stage pump comprises a conveying section and a power section arranged in sequence along the axial direction. A flow regulating assembly is arranged at the medium inlet of the conveying section. A stator assembly and a rotor assembly constituting electromagnetic induction cooperation are fixed in the power section. A driving shaft is coaxially fixed with the rotor assembly. A thrust disc is coaxially fixed on the driving shaft and cooperates with the bearing of the driving shaft.

[0007] A guide groove is formed on the working surface of the thrust disc along the radial direction. At least three floating tiles are assembled in the guide groove. At least one fulcrum abutting the groove bottom surface of the guide groove is arranged on the floating tile, so that the floating tile can produce pitching motion in the guide groove along the radial direction of the thrust disc about the fulcrum. The end surface of the floating tile away from the guide groove forms a surface contact with the bearing.

[0008] As a further scheme of the present application: the mating surface of the stator assembly and the rotor assembly is respectively provided with a stator shield sleeve and a rotor shield sleeve, and there is a flow gap between the stator shield sleeve and the rotor shield sleeve for the medium to pass through; the driving shaft is provided with a flow channel in the axial direction, and the two ends of the flow channel are respectively communicated with the flow gap and the impeller cavity of the delivery section; and the outlet end of the impeller cavity is respectively communicated with the flow gap and the delivery flow channel of the delivery section.

[0009] After the medium sequentially passes through the liquid inlet and the impeller cavity of the delivery section, part of the medium is discharged through the delivery flow channel of the delivery section to the liquid outlet, and the other part of the medium sequentially passes through the flow gap and the flow channel to flow back to the impeller cavity.

[0010] As a further scheme of the present application: the rectifying assembly is a detachable rectifying blade fixed at the liquid inlet.

[0011] As a further scheme of the present application: the length of the rotor shield sleeve is less than the length of the stator shield sleeve, and along the flow direction of the medium in the flow gap, the shaft body of the driving shaft is coaxially fixed with an anti-rotation ring which is located at a position staggered with the rotor shield sleeve; there is an annular gap between the anti-rotation ring and the stator assembly for the medium to pass through; and the outer ring of the anti-rotation ring is provided with an anti-rotation thread in the circumferential direction, which is opposite to the rotation direction of the rotor assembly.

[0012] As a further scheme of the present application: the rotor shield sleeve and / or the stator shield sleeve is provided with a resistance-increasing pattern on one side of the adjacent flow gap, which reduces the flow speed of the medium.

[0013] As a further scheme of the present application: the flow channel penetrates the driving shaft in the axial direction.

[0014] As a further scheme of the present application: the driving shaft includes a motor shaft and an impeller shaft which are coaxially fixed through a shaft coupling; the motor shaft is coaxially fixed with the rotor assembly; and the end of the impeller shaft extends to the inlet of the impeller cavity.

[0015] As a further scheme of the present application: the thrust disc includes a support seat in the form of a ring, the surface of the support seat is provided with a positioning groove for the support disc to be clamped therein, a guide groove is arranged in the radial direction of the disc surface of the support disc and penetrates the disc surface of the support disc, and the fulcrum of the floating tile abuts against the groove bottom surface of the positioning groove after penetrating the guide groove.

[0016] As a further scheme of the present application: the disc surface of the support disc is uniformly provided with guide grooves in the circumferential direction, and the number of the floating tiles corresponds to the number of the guide grooves; the floating tile is in the form of a sector, and the end surface of the adjacent support seat is provided with a guide block corresponding to the shape of the positioning groove; and the fulcrum is a spherical protrusion arranged on the guide block.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] 1. The application improves the thrust disc in the shield pump, through opening the guide groove on the thrust disc along the radial direction, and assembling the floating tile which can pitch and float along the radial direction of the thrust disc in the guide groove, when the driving shaft drives the thrust disc to occur eccentric phenomenon, the floating tile can pitch and float in the guide groove around its fulcrum, so that the end surface of the floating tile can always contact with the bearing contact surface, thereby greatly reducing the wear of the bearing, and improving the performance of the shield pump; the arrangement of the thrust disc avoids the uneven stress caused by the manufacturing and assembly tolerances of the bearing and the thrust disc, and adaptively adjusts the thrust disc to completely adhere to the bearing, reduces the pressure intensity of the axial force applied on the bearing, and makes the bearing more wear-resistant; through the medium shunt, part of the medium is directly discharged, and the other part flows through the flow gap between the shield sleeves and the flow channel on the driving shaft in turn, and then returns to the impeller cavity, which can circulate cool the rotor assembly, the stator assembly and the driving shaft, increases the pressure difference between the upstream end and the downstream end of the rotor assembly, and increases the pressure acting on the rotor assembly, so the axial force acting on the bearing is greatly reduced.

[0019] 2. The application arranges the counter-rotation ring on the driving shaft, and arranges the thread direction of the outer ring of the counter-rotation ring to be opposite to the rotating direction of the rotor assembly, so that when the rotor assembly rotates, the counter-rotation ring can drive the liquid beside the thread under the action of the thread, generate a reverse impact force, increase the flow resistance of the liquid passing through the counter-rotation ring, thereby greatly reducing the pressure of the downstream end of the rotor assembly, increasing the pressure acting on the rotor assembly, and the direction of the pressure is opposite to the axial force acting on the bearing, so the axial force acting on the bearing is further reduced.

[0020] 3. The application arranges the resistance increasing pattern on the shield sleeve to increase the flow resistance of the fluid passing through the flow gap, which has the same effect as the counter-rotation ring, increases the pressure acting on the rotor assembly, and reduces the axial force acting on the bearing; the flow channel penetrates through the driving shaft along the axial direction, which can greatly reduce the axial force acting on the bearing, and the split type arrangement of the driving shaft reduces the machining difficulty of the long shaft hole, and the motor shaft can match the impeller shafts with different lengths and different numbers of impeller stages, thereby reducing the production cost.

[0021] 4. The thrust disc of the application is composed of a support seat and a support disc, and the split type structure is easy to assemble and replace, the end surface of the floating tile is provided with a guide block which is clamped into the positioning groove, so that the end surface area of the floating tile can be increased, the floating tile is arranged in a fan shape, the face contact area with the bearing can be increased, and the spherical protrusions are arranged to enable the floating tile to freely slide in the positioning groove. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural schematic view of the shield pump of the application.

[0023] Figure 2Enlarged view of A in the figure. Figure 1 Enlarged view of B in the figure.

[0024] Figure 3 Enlarged view of A in the figure. Figure 1 Enlarged view of B in the figure.

[0025] Figure 4 Enlarged view of A in the figure.

[0026] Figure 5 Enlarged view of A in the figure.

[0027] In the figure:

[0028] 1, conveying section; 11, liquid inlet; 12, impeller cavity; 13, conveying flow channel; 14, liquid outlet;

[0029] 2, power section; 21, stator assembly; 211, stator shield sleeve;

[0030] 22, rotor assembly; 221, rotor shield sleeve;

[0031] 23, counter-rotation ring; 231, counter-rotation thread; 24, flow gap; 25, bearing;

[0032] 3, drive shaft; 31, motor shaft; 32, impeller shaft; 33, flow passage;

[0033] 4, thrust disc; 41, support seat; 411, positioning groove;

[0034] 42, support disc; 421, guide groove;

[0035] 43, floating tile; 431, guide block; 432, spherical protrusion. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0037] Please refer to Figures 1 to 5 In the embodiments of the present application, a shielded multi-stage pump, which is a vertical pump, has a pump body including a conveying section 1 and a power section 2 arranged in sequence from bottom to top.

[0038] The impeller cavity 12 is arranged axially in the conveying section 1, and a plurality of impellers are arranged axially in the impeller cavity 12. The bottom end of the impeller cavity 12 is communicated with the liquid inlet 11, and the impeller cavity 12 and the pump shell of the conveying section 1 are provided with an annular conveying flow channel 13. After the medium leaves the impeller cavity outlet at the top of the impeller cavity 12, it is discharged from the liquid outlet 14 through the flow passage 33. The liquid outlet 14 is preferably arranged at the bottom of the conveying section 1 and is located on the same straight line as the liquid inlet 11 and is separated from each other. The above is only a preferred embodiment of the conveying section 1, and the structure of the conveying section 1 can be adjusted according to different application scenarios.

[0039] The removable flow straightener blade is installed at the liquid inlet 11 of the conveying section 1, so as to improve the water flow state entering the conveying section 1 and make the water more uniform.

[0040] The power section 2 includes a stator assembly 21 and a rotor assembly 22, and the stator assembly 21 and the rotor assembly 22 are electromagnetically coupled to drive the rotation of the rotor assembly 22. The rotor assembly 22 is coaxially fixed with the motor shaft 31 arranged in the power section 2. The impeller shaft 32 is arranged axially in the conveying section 1, and a plurality of impellers are uniformly arranged on the shaft body of the impeller shaft 32. The impeller shaft 32 and the motor shaft 31 are coaxially fixed through a shaft coupling, thereby forming a driving shaft 3. The driving shaft 3 is provided with a flow passage 33 penetrating the driving shaft 3 along the axial direction. One end of the driving shaft 3 located in the power section 2 is a high-pressure end, and the other end located in the conveying section 1 is a low-pressure end.

[0041] The stator assembly 21 and the rotor assembly 22 are provided with a stator shield 211 and a rotor shield 221 at corresponding positions, and the stator shield 211 and the rotor shield 221 are provided with an annular flow gap 24.

[0042] The conveying section 1 is provided with a hole to communicate the flow gap 24 with the outlet of the impeller cavity 12. Most of the medium at the outlet of the impeller cavity 12 is discharged from the liquid outlet 14 through the conveying flow channel 13, and a small part of the medium is sequentially returned to the inlet of the impeller cavity 12 through the flow gap 24 and the flow passage 33.

[0043] In order to balance the pressure at both ends of the driving shaft 3, the stator shield 211 and the rotor shield 221 are provided with resistance increasing patterns on one side adjacent to the flow gap 24. The resistance increasing patterns are not limited in shape and can only slow down the flow speed of the medium therebetween.

[0044] The length of the rotor shield 221 is generally less than the length of the stator shield 211. Along the flow direction of the liquid in the flow gap 24, the motor shaft 31 is provided with bearings 25 at the upstream end and the downstream end of the stator shield 211 to provide two-point support for the motor shaft 31.

[0045] The motor shaft 31 is further arranged with an anti-rotation ring 23 at the upstream end and / or downstream end of the stator shield 211, and an annular gap exists between the anti-rotation ring 23 and the stator assembly 21 for the medium to pass through. In order to slow down the medium flow speed, the outer ring of the anti-rotation ring 23 is provided with anti-rotation threads 231, and the thread rotation direction of the anti-rotation threads 231 is opposite to the rotation direction of the rotor assembly 22.

[0046] The driving shaft 3 is coaxially arranged with a plurality of thrust plates 4 corresponding to the number and positions of the bearings 25. The thrust plate 4 comprises a columnar support seat 41, and the support seat 41 is axially provided with a positioning groove 411 for clamping a support disc 42. The disc body of the support disc 42 is radially provided with a guide groove 421 penetrating the support disc 42, and a plurality of floating tiles 43 corresponding to the number of the guide grooves 421 are installed in the corresponding guide grooves 421. The support seat 41 is preferably made of flexible material such as rubber, and the thrust plate 4 is axially bored for the driving shaft 3 to pass through.

[0047] The floating tile 43 is fan-shaped, and one side end face of the floating tile 43 is protrudingly provided with a guide block 431 which is matched with the shape of the guide groove 421 and slightly shorter than the length of the guide groove 421. The guide block 431 is protrudingly provided with a spherical protrusion 432 at one end facing the groove bottom face of the positioning groove 411, and the spherical protrusion 432 abuts against the groove bottom face of the positioning groove 411, so as to form a fulcrum, so that the floating tile 43 performs pitching motion along the guide groove 421 with the spherical protrusion 432 as the fulcrum. The other side end face of the floating tile 43 serves as a working face and abuts against the bearing, and when the driving shaft 3 is eccentric, the floating tile 43 floats in the guide groove 421, so that the end face of the floating tile 43 can form face contact with the end face of the bearing, thereby reducing the wear degree of the bearing. The guide groove 421 is preferably provided with three groups, and is arranged in a circumferential array on the disc face of the support disc 42. When the driving shaft 3 is eccentric, at least one group of floating tiles 43 on the thrust plate 4 abut against the bearing 25, and the floating tiles 43 are preferably arranged in three groups, thereby forming three-point stable support.

[0048] The above describes the basic principles of the present application in combination with specific embodiments, but it should be pointed out that the advantages, advantages, effects and the like mentioned in the present application are only examples and cannot be considered as the must-have of each embodiment of the present application. In addition, the above specific details are only for the purpose of example and understanding, and the above details do not limit the present application to the above specific details.

[0049] The block diagrams of the devices, apparatuses, equipment, systems referred to in this application are only illustrative examples and are not intended to require or imply that the connection, arrangement, configuration must be as shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "comprise", "have", etc. are open-ended words that are to be interpreted in the context where they are used. They are not meant to be limiting. The word "or" as used in this document is intended to mean "and / or" unless otherwise indicated. The word "and" as used in this document is intended to mean "and / or" unless otherwise indicated. The word "such as" is used in this document to mean "such as but not limited to" and is intended to mean that what follows is an example of what is included in the term being used.

[0050] It is also important to note that the devices, apparatuses and methods of the present application can be embodied in a variety of other forms, including but not limited to a device, apparatus, system, method, process, computer-readable medium, computer program product, and the like. It is also important to note that the devices, apparatuses and methods of the present application can be embodied as one or more components, either alone or in combination with other devices, apparatuses, systems, methods, processes, computer-readable media, computer program products, and the like.

[0051] The above description of disclosed aspects is given for illustrative purposes and is not intended to limit the scope of the application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0052] The above description has been given for illustrative and descriptive purposes. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof.

Claims

1. A canned multistage pump characterized by, The application relates to a kind of electromagnetic flowmeter, including the conveying section (1) and power section (2) arranged in sequence along the axial direction, the medium inlet of conveying section (1) is arranged with rectifier assembly;Power section (2) is fixed with stator assembly (21) and rotor assembly (22) constituting electromagnetic induction cooperation, driving shaft (3) is coaxially fixed with rotor assembly (22);Thrust disc (4) is coaxially fixed on driving shaft (3) and cooperates with the bearing (25) of driving shaft (3); The working surface of thrust disc (4) is provided with guide groove (421) in radial direction, at least three groups of floating tile (43) are assembled in guide groove (421), at least one fulcrum of floating tile (43) is arranged to abut the groove bottom surface of guide groove (421), so that floating tile (43) can produce pitching motion in guide groove (421) along the radial direction of thrust disc (4) around the fulcrum, the end surface of floating tile (43) away from guide groove (421) forms surface contact with bearing (25); The cooperation surface of stator assembly (21) and rotor assembly (22) is respectively provided with stator shield sleeve (211) and rotor shield sleeve (221), there is flow gap (24) between stator shield sleeve (211) and rotor shield sleeve (221) for medium to pass through, flow channel (33) is formed in driving shaft (3) along the axial direction, the two ends of flow channel (33) are respectively communicated with flow gap (24) and impeller cavity (12) of conveying section (1), the outlet end of impeller cavity (12) is respectively communicated with flow gap (24) and conveying flow channel (13) of conveying section (1); After medium passes through inlet (11) and impeller cavity (12) of conveying section (1) in sequence, part of medium is discharged through conveying flow channel (13) of conveying section (1) to liquid outlet (14), and the other part of medium flows back to impeller cavity (12) through flow gap (24) and flow channel (33) in sequence; The length of rotor shield sleeve (221) is less than the length of stator shield sleeve (211), along the flow direction of medium in flow gap (24), the shaft of driving shaft (3) is coaxially fixed with counter-rotation ring (23) which is located at the position offset from rotor shield sleeve (221), there is annular gap between counter-rotation ring (23) and stator assembly (21) for medium to pass through, the outer ring of counter-rotation ring (23) is provided with counter-rotation thread (231) in the circumferential direction, which is opposite to the rotation direction of rotor assembly (22); Rotor shield sleeve (221) and / or stator shield sleeve (211) protrude on one side of adjacent flow gap (24) and are provided with resistance increasing lines for reducing the flow rate of medium; Thrust disc (4) includes support seat (41) in the form of ring, positioning groove (411) is formed on the surface of support seat (41) for supporting disc (42) to be clamped therein, guide groove (421) is arranged in the radial direction of the disc surface of supporting disc (42) and penetrates the disc surface of supporting disc (42), the fulcrum of floating tile (43) abuts the groove bottom surface of positioning groove (411) after penetrating guide groove (421). The disc surface of the support disc (42) is uniformly arranged with guide grooves (421) in the circumferential direction, and the number of the floating tiles (43) corresponds to that of the guide grooves (421); the floating tile (43) is a sector, and the end surface of the adjacent support seat (41) is provided with a guide block (431) corresponding to the shape of the positioning groove (411), and the fulcrum is a spherical protrusion (432) arranged on the guide block (431).

2. A canned multistage pump according to claim 1, characterized in that The rectifying assembly is a detachable rectifying vane fixed at the liquid inlet (11).

3. A canned multistage pump according to claim 1, characterized in that The overflow channel (33) penetrates the drive shaft (3) in the axial direction.

4. The canned multistage pump of claim 1, wherein The drive shaft (3) comprises a motor shaft (31) and an impeller shaft (32) coaxially fixed through a shaft coupling, the motor shaft (31) is coaxially fixed with the rotor assembly (22), and the end of the impeller shaft (32) extends to the inlet of the impeller cavity (12).

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