Motor shaft for pipeline centrifugal pump

Abstract

The utility model relates to a motor shaft for a pipeline centrifugal pump. Belongs to the technical field of mechanical manufacturing. The utility model mainly provides a corrosion-resistant motor shaft for a pipeline centrifugal pump or solves the problem of mechanical seal failure caused by corrosion. The mechanical seal is mainly characterized by comprising a shaft section used for installing the mechanical seal; and a heat-resistant steel and stainless steel welding layer is arranged at the outer diameter of the shaft section. The device has the characteristic of prolonging the service life of the pipeline centrifugal pump, and is mainly used for repairing a new motor shaft of the pipeline centrifugal pump or a motor shaft with mechanical seal failure caused by corrosion.

Description

Motor shaft for pipeline centrifugal pumps Technical Field

[0001] This utility model belongs to the field of mechanical manufacturing technology, specifically relating to a motor shaft suitable for pipeline centrifugal pumps, especially suitable for pump equipment in high temperature, humid and corrosive liquid environments. Background Technology

[0002] Currently, pipeline centrifugal pumps (such as water pumps and oil pumps) are widely used in industrial fields, and their sealing structure typically employs mechanical seals. In practical use, when pumps operate in high-temperature, humid environments or when conveying corrosive liquids, the motor shaft at the mechanical seal is prone to corrosion. This leads to a decrease in the fit between the mechanical seal and the shaft, causing leaks such as water and oil. Existing solutions often focus on replacing the mechanical seal or bearings, neglecting the inherent corrosion resistance of the motor shaft itself. The corrosion resistance, high-temperature resistance, and crack resistance of the mating area between the motor shaft and the mechanical seal directly affect the pump's sealing performance and service life; therefore, a technical solution that can improve the corrosion resistance of the shaft section is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to address the problem of pump leakage caused by corrosion of existing motor shafts. This invention provides a motor shaft for pipeline centrifugal pumps, which significantly improves the corrosion resistance, high temperature resistance, and wear resistance of the shaft section by improving the material of the mechanical seal mating area, thereby extending the service life of pump equipment.

[0004] The technical solution of this utility model is: a motor shaft for a pipeline centrifugal pump, including a shaft section for installing a mechanical seal, characterized in that: a heat-resistant steel-stainless steel welded layer is provided at the outer diameter of the shaft section.

[0005] The thickness of the heat-resistant steel stainless steel welded layer in the technical solution of this utility model is 1.0-4.5mm, 1.5-3.0mm or 2mm.

[0006] The diameter tolerance of the shaft segment described in the technical solution of this utility model is js8, the surface roughness is Ra0.8, and the tolerance grades for cylindricity, circular runout, and coaxiality are 7.

[0007] The heat-resistant stainless steel welded layer described in the technical solution of this utility model is formed by welding with heat-resistant stainless steel welding rods / A412. The welding rods have rutile coatings, and the welding wire material is Cr26Ni26Mo2, pure austenitic stainless steel. The welding rods have good corrosion resistance, heat resistance, crack resistance, and wear resistance.

[0008] In the technical solution of this utility model, the outer surface of the heat-resistant steel stainless steel welded layer is machined and ground to ensure fitting accuracy.

[0009] The motor shaft in the technical solution of this utility model is made of medium carbon steel quenched and tempered material.

[0010] The motor shaft in the technical solution of this utility model is made of 45 steel or 40Cr.

[0011] The beneficial effects of this utility model technology are:

[0012] 1. By adding a heat-resistant steel and stainless steel welded layer to the outside of the shaft section where the mechanical seal is installed on the motor shaft, it can effectively resist the erosion of high temperature, humidity and corrosive liquids, and avoid the shaft section from rusting;

[0013] 2. The corrosion resistance, high temperature resistance, and crack resistance of the weld layer significantly improve the fit stability between the mechanical seal and the shaft, reducing the risk of leakage;

[0014] 3. Shaft segment dimensional accuracy (diameter tolerance js8, surface roughness Ra0.8, cylindricity, circular runout, coaxiality and other tolerance grades 7) and surface grinding treatment ensure the installation accuracy of the mechanical seal and extend the overall service life of pump equipment;

[0015] 4. Applicable to the repair of newly manufactured motor shafts and rusted motor shafts, reducing equipment maintenance costs.

[0016] This utility model has the feature of improving the service life of pipeline centrifugal pumps. It is mainly used for the repair of newly manufactured motor shafts or motor shafts of pipeline centrifugal pumps that have been corroded and caused mechanical seal failure. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the structure of this utility model.

[0018] In the diagram: 1-Welding layer; 2-Motor shaft; 3-Mechanical seal; 4-Impeller fixing bolt; 5-Impeller; 6-Impeller baffle; 7-Connecting seat. Detailed Implementation

[0019] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0020] As shown in Figure 1, one embodiment of the motor shaft for a pipeline centrifugal pump of this utility model includes a motor shaft 2. The motor shaft 2 is the motor shaft of the pipeline centrifugal pump, which is an 18.5KW circulating water pump, and includes a motor shaft section for mounting a mechanical seal 3.

[0021] The motor shaft 2 includes a motor shaft body and a heat-resistant steel-stainless steel welded layer 1 surrounding the outside of the motor shaft body or the shaft section where the mechanical seal 3 is installed. The motor shaft body is made of 45mm steel and has a diameter of 45mm. Due to use in high-temperature, humid, and corrosive liquid environments, the 45mm steel motor shaft corrodes, which is the main cause of mechanical seal failure and leakage. As shown by the arrow in the figure, the outer surface of the motor shaft 2 that mates with the mechanical seal 3 is the part that needs to be treated. Upon disassembling the water pump, it was found that the part of the motor shaft 2 where the mechanical seal 3 is installed was corroded. The motor shaft 2 is made of medium carbon steel tempered material, 45mm, which has poor corrosion resistance. In humid and high-temperature environments, the mechanical seal installation location is prone to corrosion. If the motor shaft body were made of 40Cr steel, the motor shaft 2 would also corrode in high-temperature, humid, and corrosive liquid environments, leading to mechanical seal 3 failure.

[0022] The rusted portion of motor shaft 2 was machined to φ41, and the rusted section of the motor shaft was welded. The section was repaired using heat-resistant steel and stainless steel welding rods (A412 / 2.5mm). Before welding, the welding rods were baked at 200-250℃ for 1 hour. The repaired section of the motor shaft was welded to φ5, machined to φ45+0.06, and ground to φ45±0.02, achieving a surface roughness Ra0.8, circular runout 0.02, and cylindricity 0.01. The treated motor shaft 2 was then reinstalled into the water pump, and the mechanical seal and bearings were replaced to prevent further corrosion. The expected service life of motor shaft 2 is over 20 years, resolving the water pump leakage problem. The repair was achieved using heat-resistant steel and stainless steel welding rods (A412, rutile coating, Cr26Ni26Mo2, pure austenitic stainless steel). The welding rods exhibit good corrosion resistance, heat resistance, crack resistance, and wear resistance.

[0023] After welding the mechanical seal installation position on motor shaft 2 with heat-resistant stainless steel welding rods, and then machining and grinding it to a thickness of more than 1mm on each side, the corrosion resistance, high temperature resistance, crack resistance and wear resistance of motor shaft 2 can be significantly improved.

[0024] The above specific implementation examples are merely explanations of this utility model and are not limitations thereof. Those skilled in the art can make non-inventive modifications to the above implementation examples as needed based on this utility model, but such modifications are protected by patent law as long as they fall within the scope of the claims of this utility model.

Claims

1. A motor shaft for a pipeline centrifugal pump, comprising a shaft segment for mounting a mechanical seal (3) of a motor shaft (7), characterized in that: The outer diameter of the shaft section is provided with a heat-resistant steel stainless steel welded layer (1).

2. A motor shaft for a tubular centrifugal pump according to claim 1, characterized in that: The thickness of the heat-resistant steel stainless steel welded layer (1) is 1.0-4.5 mm.

3. The motor shaft for a pipeline centrifugal pump according to claim 2, characterized in that: The thickness of the heat-resistant steel stainless steel welded layer (1) is 1.5-3.0 mm.

4. The motor shaft for a pipeline centrifugal pump according to claim 1, characterized in that: The thickness of the heat-resistant steel stainless steel welded layer (1) is 2 mm.

5. The motor shaft for a pipeline centrifugal pump according to any one of claims 1-4, characterized in that: The diameter tolerance of the shaft segment is js8, the surface roughness is Ra0.8, and the tolerance grades for cylindricity, circular runout, and coaxiality are 7.

6. The motor shaft for a pipeline centrifugal pump according to any one of claims 1-4, characterized in that: The heat-resistant stainless steel welded layer (1) is formed by welding with heat-resistant stainless steel welding rods / A412. The welding rods are rutile type with a flux coating. The welding wire material is Cr26Ni26Mo2, pure austenitic stainless steel. The welding rods have good corrosion resistance, heat resistance, crack resistance and wear resistance.

7. The motor shaft for use in a tubular centrifugal pump according to claim 5, characterized in that: The heat-resistant stainless steel welded layer (1) is formed by welding with heat-resistant stainless steel welding rods / A412. The welding rods are rutile type with a flux coating. The welding wire material is Cr26Ni26Mo2, pure austenitic stainless steel. The welding rods have good corrosion resistance, heat resistance, crack resistance and wear resistance.

8. The motor shaft for a pipeline centrifugal pump according to any one of claims 1-4 and 7, characterized in that: The outer surface of the heat-resistant steel stainless steel welded layer (1) is machined and ground to ensure fitting accuracy.

9. The motor shaft for a pipeline centrifugal pump according to any one of claims 1-4 and 7, characterized in that: The motor shaft (7) is made of medium carbon steel tempered material.

10. A motor shaft for a pipeline centrifugal pump of the type defined in claim 9, characterized by: The motor shaft (7) is made of 45 steel or 40Cr.

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