Rotor limiting structure for regulating rotor leakage of multistage centrifugal pump without stopping

Abstract

The utility model relates to centrifugal pump technical field, and specifically is a rotor limiting structure that can not stop regulating multistage centrifugal pump rotor amount of hunting. The one end of pump shaft is bimonthly ladder shape near oil pump, and the side surface of bearing gland is connected with fixed ring near oil pump, and the inside of fixed ring is provided with the limiting component that can displace along the axial direction of pump shaft between pump shaft outer layer ladder, and the top of bearing gland is provided with the adjusting mouth opposite limiting component, drives the axial displacement of limiting component through adjusting mouth, changes the gap size with pump shaft inner layer ladder, and the extension section is connected with oil pump and is set up in the end of pump shaft near oil pump. The position of limiting component is controlled and observed through adjusting mouth, thereby carries out mechanical limiting to pump shaft inner layer ladder, can realize the restraint to rotor axial hunting amount under the operating state, solves the problem that the axial hunting amount of traditional balance disc structure is too big in the start -stop stage.

Description

Technical Field

[0001] This utility model relates to the field of centrifugal pump technology, specifically a rotor limiting structure that can adjust the rotor displacement of a multi-stage centrifugal pump without stopping the pump. Background Technology

[0002] In modern industrial fluid transport systems, high-power, high-speed multistage centrifugal pumps are widely used as key equipment in petrochemical, energy, and power industries. These pump sets typically employ a sliding bearing support structure, with one end of the pump shaft connected to the drive motor via a flexible coupling, and the other end connected to an oil pump. A balance disc mechanism is relied upon to dynamically balance the rotor's axial force. During operation, the complex hydrodynamic characteristics generated by the high-speed rotation of the impeller can cause axial movement of several millimeters in the rotor system. Figure 1 .

[0003] The existing balance disc structure has inherent dynamic characteristics during the start-up and shutdown phases: the initial fluid flow impact causes the rotor to shift towards the non-drive end, and after the head is established, the fluid reaction force pushes the rotor towards the motor side. This periodic oscillation is transmitted to the motor rotor through the coupling. Long-term operation may cause the motor bearing positioning to shift. At the same time, a large axial movement will prolong the time for the balance disc to balance the axial force, accelerate its wear, and affect the reliability of the shaft sealing system. Utility Model Content

[0004] The present invention aims to solve the above problems, thereby providing a rotor limiting structure that can adjust the rotor displacement of a multi-stage centrifugal pump without stopping the pump.

[0005] The technical solution adopted by this utility model to solve the aforementioned problem is:

[0006] A rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down the pump includes a pump shaft and a bearing cover at the non-drive end of the pump body. The pump shaft has a double-layer stepped shape at the end near the oil pump. A fixing ring is connected to the side of the bearing cover near the oil pump. A limiting component that can be displaced along the pump shaft axially is provided between the inner side of the fixing ring and the outer step of the pump shaft. An adjustment port is provided on the top of the bearing cover, which is opposite to the limiting component. The axial displacement of the limiting component is driven through the adjustment port. An extension section connected to the oil pump is provided at the end of the pump shaft near the oil pump.

[0007] Compared with the prior art, the outstanding features of this utility model, which adopts the above technical solution, are:

[0008] By adjusting the position of the limiting component through the adjustment port and observing it, the inner step of the pump shaft is mechanically limited. This can constrain the axial movement of the rotor during operation, solving the problem of excessive axial movement caused by the traditional balance disc structure during start-up and shutdown. It also reduces the risk of rotor offset due to cumulative displacement, improves the operational stability of the shaft sealing system, and compared with the traditional stop-and-adjustment method, this non-stop adjustment function can maintain continuous operation of the equipment and reduce maintenance downtime.

[0009] As a preferred embodiment, a further technical solution of this utility model is:

[0010] Furthermore, bolt holes are made on the retaining ring and the bearing cover respectively, and they are connected by connecting bolts. The fixing method of using bolt holes and connecting bolts is convenient for disassembly and maintenance and can maintain the positioning accuracy of the retaining ring and the bearing cover. The bolt connection can adapt to the preload adjustment requirements under different working conditions and is more conducive to on-site maintenance operations compared with fixing methods such as welding.

[0011] Furthermore, the extension section has the same diameter as the outer stepped structure of the pump shaft. A sleeve is provided on one side of the extension section, and the sleeve is detachably connected to the end of the pump shaft. Since the modification is carried out on the original pump shaft, the length of the original pump shaft is insufficient to support the connection of the oil pump. Therefore, the extension section is quickly disassembled and assembled by connecting it to the end of the pump shaft with the sleeve, ensuring the axial connection strength while ensuring the installation length.

[0012] Furthermore, the limiting component includes an adjusting sleeve located between the inner side of the fixed ring and the outer step of the pump shaft. The outer periphery of one side of the adjusting sleeve and the inner side of the fixed ring are both provided with threaded structures for cooperation. The outer periphery of the other side of the adjusting sleeve is provided with adjusting blocks at axial intervals. The adjusting port is opposite to the adjusting block. A slot is opened at the inner end of the adjusting sleeve away from the oil pump side. A bearing disc is assembled in the slot. The outer diameter of the bearing disc and the slot form an interference fit. The inner side of the bearing disc and the inner step sidewall of the pump shaft form a limiting gap. The adjusting block is moved by adjusting the adjusting port to rotate the adjusting sleeve, and the adjusting sleeve moves axially through the threaded structure. The slot will drive the bearing disc to move to limit the pump shaft and prevent excessive movement.

[0013] Furthermore, two adjustment ports are symmetrically arranged on the top of the bearing cover with the pump shaft as the axis. The two adjustment ports can be operated separately to achieve bidirectional adjustment. When a flat-headed chisel is inserted into one adjustment port to drive the adjustment sleeve to move, the other adjustment port serves as an observation hole and provides a light source. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the traditional structure of a centrifugal pump in the background art;

[0015] Figure 2 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0016] Figure 3 for Figure 2 A magnified schematic diagram of the structure of part A in the diagram;

[0017] Figure 4 This is a top view of the bearing cap structure according to an embodiment of the present invention;

[0018] Figure 5 This is a schematic diagram of the structure of the fixing ring in an embodiment of the present invention;

[0019] Figure 6 This is a schematic diagram of the bearing disc structure according to an embodiment of the present invention;

[0020] Figure 7 This is a schematic diagram of the structure of the adjusting sleeve in an embodiment of the present invention;

[0021] Figure 8 This is a schematic diagram of the structure of the extension section in an embodiment of the present utility model;

[0022] The components in the diagram are labeled as follows: 1. Pump shaft; 2. Bearing cover; 3. Fixing ring; 4. Adjustment port; 5. Extension section; 6. Adjustment sleeve; 7. Adjustment block; 8. Bearing disc; 9. Oil pump. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments, the purpose of which is only to better understand the content of the present invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0024] A rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down the pump includes a pump shaft 1 and a bearing cover 2 at the non-drive end of the pump body. The end of the pump shaft 1 near the oil pump 9 is in a double-layer stepped shape. A fixing ring 3 is connected to the side of the bearing cover 2 near the oil pump 9. A limiting component that can be displaced along the axial direction of the pump shaft 1 is provided between the inner side of the fixing ring 3 and the outer step of the pump shaft 1. An adjustment port 4 is opened on the top of the bearing cover 2, which is opposite to the limiting component. The axial displacement of the limiting component is driven by the adjustment port 4, thereby changing the gap size between the limiting component and the inner step of the pump shaft 1. An extension section 5 connected to the oil pump 9 is provided at the end of the pump shaft 1 near the oil pump 9. The end face structure of the extension section 5 is the same as the end face structure of the original pump shaft 1.

[0025] Furthermore, bolt holes are opened on the retaining ring 3 and the bearing cover 2 respectively, and they are connected by connecting bolts. The fixing method of bolt holes and connecting bolts is convenient for disassembly and maintenance and can maintain the positioning accuracy of retaining ring 3 and bearing cover 2. The bolt connection can adapt to the preload adjustment requirements under different working conditions and is more conducive to on-site maintenance operations compared with fixing methods such as welding.

[0026] Furthermore, the extension section 5 has the same diameter as the outer stepped structure of the pump shaft 1. A sleeve is provided on one side of the extension section 5. The sleeve is detachably connected to the end of the pump shaft 1. Since the modification is carried out on the original pump shaft, the length of the original pump shaft 1 is insufficient to support the connection of the oil pump. Therefore, the extension section 5 is quickly disassembled and assembled by connecting the sleeve to the end of the pump shaft 1, ensuring the axial connection strength while ensuring the installation length. The sleeve is fitted on the pump shaft 1. The sleeve and the pump shaft 1 can be connected by a thread or by a pin with a pin hole.

[0027] Furthermore, the limiting component includes an adjusting sleeve 6 located between the inner side of the fixed ring 3 and the outer step of the pump shaft 1. One side of the adjusting sleeve 6 has a threaded structure that works with the inner side of the fixed ring 3. The other side of the adjusting sleeve 6 has adjusting blocks 7 spaced axially at intervals of 15° on its outer circumference. The adjusting port 4 is opposite to the adjusting blocks 7. A slot is opened at the inner end of the adjusting sleeve 6 away from the oil pump 9. A bearing disc 8 is installed in the slot. The bearing disc 8 is an angular contact ball bearing. The outer diameter of the bearing disc 8 is larger than the diameter of the pump shaft 1. The outer diameter of the bearing disc 8 forms an interference fit with the slot. The inner side of the bearing disc 8 forms a limiting gap with the inner step sidewall of the pump shaft 1. The adjusting sleeve 6 is rotated by moving the adjusting block 7 through the adjusting port 4, and the adjusting sleeve 6 moves axially through the threaded structure. The slot will drive the bearing disc 8 to move and limit the pump shaft 1 to prevent excessive movement.

[0028] Furthermore, two adjustment ports 4 are symmetrically arranged on the top of the bearing cover 2 with the pump shaft 1 as the axis. The two adjustment ports 4 can operate the adjustment block 7 to achieve bidirectional adjustment. A pestle is inserted into one adjustment port 4. When the pestle moves the adjustment sleeve 6, it serves as an observation hole and provides a light source through the other adjustment port 4. The pestle can be a flat-headed chisel or a screwdriver.

[0029] When abnormal axial movement occurs during pump unit operation, the operator inserts a pestle through the adjustment port 4 on the top of the bearing cover 2, which is convenient for applying force. The pestle is manually pressed down or struck, and tilted downwards to apply force to the upper surface of the nearest adjustment block 7, thereby driving the adjustment sleeve 6 to rotate. This causes the adjustment sleeve 6 to rotate forward along the threaded structure inside the fixing ring 3. At this time, the adjustment sleeve 6 drives the bearing disc 8 to move axially through the groove until the inner sleeve of the bearing disc 8 abuts against the inner stepped sidewall of the pump shaft 1. Then, the adjustment sleeve 6 is rotated in the opposite direction by about 15°, through symmetrical arrangement. The adjustment port 4 uses a light source to assist in confirming the adjustment amount. The light source is aligned with the gap at one adjustment port 4, and the light is observed to pass through the gap at the other adjustment port 4. At this time, the gap size is generally less than 0.5mm. When the rotor causes non-drive end displacement due to the impact of the start-stop liquid flow, the mechanical limit formed by the bearing disc 8 and the inner step of the pump shaft 1 can reduce the gap and prevent excessive movement. The gap can be enlarged by rotating the adjustment sleeve 6 in the opposite direction, realizing dynamic control of the axial movement without stopping the machine, effectively solving the problems of motor bearing misalignment and seal wear caused by the traditional balance disc structure.

[0030] The above description is only a preferred embodiment of the present utility model and does not limit the scope of the present utility model. All equivalent changes made based on the content of the present utility model specification and its drawings are included within the scope of the present utility model.

Claims

1. A rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down the pump, comprising a pump shaft and a bearing cap at the non-drive end of the pump body, wherein the end of the pump shaft near the oil pump is in a double-layer stepped shape, characterized in that: A retaining ring is connected to the side of the bearing cover near the oil pump. A limiting component that can be displaced along the pump shaft axially is provided between the inner side of the retaining ring and the outer step of the pump shaft. An adjustment port opposite to the limiting component is opened on the top of the bearing cover. The axial displacement of the limiting component is driven by the adjustment port. An extension section connected to the oil pump is provided on the pump shaft near the oil pump end.

2. The rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down, as described in claim 1, is characterized in that: Bolt holes are made on the retaining ring and the bearing cover respectively, and they are connected by connecting bolts.

3. The rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down, as described in claim 1, is characterized in that: The extension section has the same diameter as the outer stepped structure of the pump shaft, and a sleeve is provided on one side of the extension section. The sleeve is detachably connected to the end of the pump shaft.

4. The rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down, as described in claim 3, is characterized in that: The limiting assembly includes an adjusting sleeve located between the inner side of the fixed ring and the outer step of the pump shaft. The outer periphery of one side of the adjusting sleeve and the inner side of the fixed ring are provided with threaded structures for matching. The outer periphery of the other side of the adjusting sleeve is provided with adjusting blocks at axial intervals. The adjusting port is opposite to the adjusting block. A slot is opened at the inner end of the adjusting sleeve away from the oil pump side. A bearing disc is assembled in the slot. The outer diameter of the bearing disc and the slot form an interference fit. The inner side of the bearing disc and the inner step sidewall of the pump shaft form a limiting gap.

5. The rotor limiting structure for adjusting the rotor displacement of a multi-stage centrifugal pump without shutting down, as described in claim 4, is characterized in that: Two adjustment ports are symmetrically arranged on the top of the bearing cover with the pump shaft as the axis.

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