Deep-well pump and multi-beam laser welding method for impeller of deep-well pump

Abstract

According to the deep-well pump and the multi-beam laser welding method for the impeller of the deep-well pump, a groove is formed in the radial end face of a hub inlet of the impeller, an end face convex ring and a runner side convex ring are arranged on the radial end face of a hub outlet of a guide vane, the end face convex ring is in clearance fit with the groove, and the runner side convex ring is matched with the runner side hub face of the impeller in an abutting mode; a through flow guide through groove is formed in the outlet end side of a hub of the impeller, flow guide blades are arranged in the flow guide through groove in the radial direction, a through jet flow through groove is formed in the inlet end side of a hub of the guide vane, a flow guide ring is arranged in the jet flow through groove, the axis of the flow guide through groove and the axis of the jet flow through groove are collinear, and the axis points to the outlet position of the guide vane. The problems of flutter, cavitation, noise vibration, maintenance and the like are solved, and then the service life of the deep-well pump is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid machinery, in particular to a deep well pump, and more particularly to a multi-beam laser welding method for a deep well pump and an impeller thereof. Background Art

[0002] A deep-well pump is a mechanical device used to extract groundwater from deep wells. Featuring compact structure, high efficiency, and stable performance, deep-well pumps are widely used in agricultural irrigation, industrial water supply, urban water supply, and drainage. Existing deep-well pumps on the market often suffer from poor flow stabilization at high speeds, high noise and vibration, and difficulty in maintenance. As demand for deep-well pumps increases, the demand for improved performance is growing. Consequently, optimizing the design of deep-well pumps is essential.

[0003] The prior art CN220850045U discloses a new type of high-speed deep well pump, including a motor 1 and a pump body 2. The motor 1 shaft 3 directly passes through multiple impellers 4 in the pump body 2, thereby synchronously driving them to rotate; the motor 1 includes a barrel 5 and a front end cover 6 and a rear end cover 7 arranged in the barrel 5. The front end cover 6 and the barrel 5, and the rear end cover 7 and the barrel 5 are all fixedly connected by laser welding. In order to improve the coaxiality and stability of the shaft 3, the premise is that the bearing grooves in the front end cover 6 and the rear end cover 7 must ensure concentricity. The front end cover 6 and the barrel 5, and the rear end cover 7 and the barrel 5 are laser welded to obtain a firm connection, so that it is placed in a dual-spindle lathe, and the bearing grooves in the front end cover 6 and the rear end cover 7 are clamped once and processed twice to ensure their concentricity. In this way, the motor 1 shaft 3 can also ensure stability under high-speed operation.

[0004] However, the above structure has design limitations, and during the actual application of deep-well pumps, the applicant discovered a number of defects: 1. At high speeds, the impeller will vibrate, creating a very loud noise that can lead to safety accidents; 2. As the pump body runs longer, the guide vanes experience severe cavitation, which leads to severe wear and tear, resulting in low diversion efficiency; 3. The impeller, a working component, is severely worn and cracked, posing a significant safety hazard. Considering the complex internal waterway structure of deep-well pumps, the applicant has proposed a multi-beam laser welding method for deep-well pumps and their impellers to address these issues, including flutter, cavitation, noise, vibration, and maintenance. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a multi-beam laser welding method for a deep well pump and its impeller.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The pump is connected with the pump end face through the through-hole, and the pump end faces the bottom end.The pump end faces the bottom end of the pump end and the pump end face are connected with the pump end by the hydraulic pump cap to the hydraulic pump cap. The hydraulic pump is connected with the hydraulic pump cap to the hydraulic pump cap.

[0008] Furthermore, both ends of the guide vane are movably mounted on the groove wall surface of the drainage groove through a short shaft.

[0009] Furthermore, the cross section of the guide ring is triangular, and the guide ring is installed at the outlet side of the jet flow groove.

[0010] Furthermore, the impeller includes a first blade and a second blade, and the second blade is fixed to the outlet end of the first blade through a connecting plate.

[0011] Furthermore, the first blade is installed between the impeller hub and the impeller cover plate, and a buffer gap exists between the second blade and the first blade, the impeller hub and the impeller cover plate.

[0012] Furthermore, the radial length of the second blade is L1, and the radial width of the inlet flow channel of the guide vane is L2, wherein 0.3L2≤L1<0.8L2.

[0013] Furthermore, the second blade is a straight blade.

[0014] A multi-beam laser welding method for an impeller, wherein the impeller is an impeller of a deep well pump, comprises the following steps:

[0015] Pre-treat all parts of the impeller to be welded to remove surface impurities and oil stains to ensure a clean welding surface;

[0016] Fix the impeller parts to be welded on the welding fixture, and adjust the impeller position through the fixture to ensure the impeller position is stable during the welding process;

[0017] At least three laser beams are used to act simultaneously on the impeller portion to be welded, wherein one main laser beam is incident vertically to the welding portion, and the remaining auxiliary laser beams are incident at an angle of 10° to 30° to the main laser beam;

[0018] During the welding process, the energy distribution and pulse frequency of each laser beam are adjusted in real time according to the material and thickness of the impeller. At the same time, the deformation of the impeller is monitored in real time through a high-precision displacement sensor. When the deformation exceeds the preset threshold, the energy input of the laser beam and the welding speed are automatically adjusted through feedback.

[0019] After welding is completed, the welded joint is heat treated. The welded impeller is heated to 300-500℃, kept at this temperature for 2-4 hours, and then cooled with the furnace to eliminate welding residual stress.

[0020] Furthermore, in the pretreatment step, a combination of chemical corrosion and mechanical polishing is used. The impeller surface to be welded is first corroded with a nitric acid solution with a mass fraction of 5-10% for 3-5 minutes, and then mechanically polished with sandpaper with a particle size of 800-1200 mesh.

[0021] Furthermore, the fixture adopts an adaptive flexible clamping structure, which can automatically adjust the clamping point and clamping force, and the fixture has a vibration isolation function.

[0022] Furthermore, a high-speed camera is used to collect real-time image information of the molten pool during the welding process, and an image processing algorithm is used to analyze the shape, size and dynamic changes of the molten pool. The parameters of the laser beam are adjusted based on the analysis results.

[0023] Furthermore, after heat treatment, ultrasonic flaw detection and metallographic structure analysis are performed on the weld joints, and repair welding is performed on the defective parts.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. When the impeller moves at high speed, flutter and noise problems may occur due to fluid (cavitation, unstable flow, etc.), mechanical failure (bearing damage, shaft deformation, etc.), installation and connection (insufficient installation accuracy, loose connection, etc.), and imbalance (uneven mass distribution, impeller damage or loss, etc.). Therefore, in order to better stabilize the impeller and reduce flutter, the applicant has adopted a method of providing a groove on the radial end face of the impeller hub inlet, and an end face convex ring and a flow channel side convex ring on the radial end face of the guide vane hub outlet, wherein the end face convex ring is fitted with a gap in the groove, and a buffer fluid is assisted in the gap, which greatly alleviates the occurrence of flutter. In addition, the flow channel side convex ring is in contact with the flow channel side hub surface of the impeller, which limits the displacement of the impeller in the radial direction and stabilizes the high-speed operation of the impeller.

[0026] 2. Due to the unstable pressure and excessive resistance in the guide vanes, and the changes in operating conditions such as flow rate and speed, cavitation is also very likely to occur in the guide vanes. The generation of cavitation will cause abnormal noise in the deep well pump, and the generation and burst of bubbles will seriously affect the quality and service life of the guide vanes. The applicant has set a through drainage groove on the outlet side of the impeller hub, and a guide vane is radially arranged in the drainage groove. The hub inlet side of the guide vane is provided with a through jet flow groove, and a guide ring is provided in the jet flow groove. The axis of the drainage flow groove is aligned with the axis of the jet flow groove. The center lines are collinear, and the axis line points to the guide vane outlet position. The above structure increases the pressure of the fluid in the guide vane, stabilizes the operating conditions, and reduces the occurrence of noise. In addition, the applicant has also made pressurization improvements to the guide vane inlet. For example, the impeller includes a first blade and a second blade. The second blade is fixed to the outlet end of the first blade through a connecting plate. The first blade is installed between the impeller hub and the impeller cover plate. There is a buffer gap between the second blade and the first blade, the impeller hub and the impeller cover plate, which can also assist in improving the inlet flow state of the guide vane, and the noise and vibration are naturally reduced.

[0027] 3. The impeller is very easy to be damaged during long-term operation. The main reason is the improper selection of welding materials and processes, such as mismatched welding materials, unreasonable welding process parameters, and problems such as porosity, slag inclusion, and incomplete welding. Taking the above reasons into consideration, the applicant optimized the laser welding process of the impeller, such as pre-treating the impeller parts to be welded to remove surface impurities and oil stains to ensure a clean welding surface; fixing the impeller parts to be welded on the welding fixture, adjusting the impeller position through the fixture to ensure the stability of the impeller position during welding; using at least three laser beams to act simultaneously on the impeller parts to be welded In this process, one main laser beam is incident perpendicularly to the weld site, while the remaining auxiliary laser beams are incident at an angle of 10° to 30° with the main laser beam. During the welding process, the energy distribution and pulse frequency of each laser beam are adjusted in real time based on the material and thickness of the impeller. A high-precision displacement sensor monitors the impeller's deformation in real time. When the deformation exceeds a preset threshold, the laser beam's energy input and welding speed are automatically adjusted. After welding, the welded joint is heat treated by heating the impeller to 300-500°C, holding it for 2-4 hours, and then cooling it in the furnace to eliminate residual welding stress. This laser welding process makes the impeller weld more secure, thereby reducing the failure rate of the entire machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is an axial cross-sectional view of a deep well pump in the prior art;

[0029] Figure 2 It is a schematic diagram of a partially improved structure of the deep well pump of the present invention;

[0030] Figure 3 for Figure 2 An enlarged schematic diagram of a partially improved structure A of a deep well pump;

[0031] Figure 4 for Figure 2 An enlarged schematic diagram of the improved structure B of the deep well pump.

[0032] In the figure: motor 1, support base 2, coupling 3, water inlet section 4, multi-stage pump casing 5, pump shaft 6, water outlet section 7, impeller 8, groove 81, drainage groove 82, guide vane 83, first blade 84, impeller cover 85, connecting plate 86, second blade 87, guide vane 9, end face convex ring 91, flow channel side convex ring 92, jet flow groove 93, guide ring 94, radial length L1 of second blade 87, radial width L2 of the inlet flow channel of guide vane 9. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] The present invention will be described in further detail below with reference to the accompanying drawings.

[0035] like Figure 1-4 As shown, a deep well pump includes a motor 1, the lower end of the motor 1 is connected to the support base 2, the upper end of the motor 1 is connected to the water inlet section 4 through a coupling 3, a multi-stage pump casing 5 is sleeved on the pump shaft 6 and fixed downstream of the water inlet section 4, a multi-stage impeller guide vane assembly is installed on the pump shaft 6 and located in the multi-stage pump casing 5, and a water outlet section 7 is installed downstream of the multi-stage pump casing 5; it is characterized in that: the multi-stage impeller guide vane assembly includes an impeller 8 and a guide vane 9; the radial end face of the hub inlet of the impeller 8 is provided with a groove 81, and the radial end face of the hub outlet of the guide vane 9 is provided with an end face A convex ring 91 and a flow channel side convex ring 92, wherein the end face convex ring 91 is clearance-fitted with the groove 81, and the flow channel side convex ring 92 is abutted against the flow channel side hub surface of the impeller 8; a through drainage groove 82 is provided on the outlet end side of the hub of the impeller 8, and a guide vane 83 is radially provided in the drainage groove 82, and a through jet flow groove 93 is provided on the inlet end side of the hub of the guide vane 9, and a guide ring 94 is provided in the jet flow groove 93, and the axial center line of the drainage groove 82 is collinear with the axial center line of the jet flow groove 93, and the axial center line points to the outlet position of the guide vane 9.

[0036] Furthermore, both ends of the guide vane 83 are movably mounted on the groove wall surface of the drainage groove 82 via a short shaft.

[0037] Furthermore, the cross section of the guide ring 94 is triangular, and the guide ring 94 is installed at the outlet side of the jet flow groove 93 .

[0038] Furthermore, the impeller 8 includes a first blade 84 and a second blade 87 , and the second blade 87 is fixed to the outlet end of the first blade 84 via a connecting plate 86 .

[0039] Furthermore, the first blade 84 is installed between the impeller 8 hub and the impeller cover plate 85 , and there is a buffer gap between the second blade 87 and the first blade 84 , the impeller 8 hub and the impeller cover plate 85 .

[0040] Furthermore, the radial length of the second blade 87 is L1, and the radial width of the inlet flow passage of the guide vane 9 is L2, wherein 0.3L2≤L1<0.8L2.

[0041] Furthermore, the second blade 87 is a straight blade.

[0042] The second blade is not integrally formed with the first blade and installed between the impeller 8 hub and the impeller cover 85. This is because the second blade is placed in the cavity at the outlet of the first blade to better guide and rectify the flow. After rectification, the disturbance is reduced, the efficiency of the fluid entering the guide vane is improved, the diversion effect is better, and the noise and vibration are reduced.

[0043] A multi-beam laser welding method for an impeller, wherein the impeller is an impeller of a deep well pump, comprises the following steps:

[0044] Pre-treat all parts of the impeller to be welded to remove surface impurities and oil stains to ensure a clean welding surface;

[0045] Fix the impeller parts to be welded on the welding fixture, and adjust the impeller position through the fixture to ensure the impeller position is stable during the welding process;

[0046] At least three laser beams are used to act simultaneously on the impeller portion to be welded, wherein one main laser beam is incident vertically to the welding portion, and the remaining auxiliary laser beams are incident at an angle of 10° to 30° to the main laser beam;

[0047] During the welding process, the energy distribution and pulse frequency of each laser beam are adjusted in real time according to the material and thickness of the impeller. At the same time, the deformation of the impeller is monitored in real time through a high-precision displacement sensor. When the deformation exceeds the preset threshold, the energy input of the laser beam and the welding speed are automatically adjusted through feedback.

[0048] After welding is completed, the welded joint is heat treated. The welded impeller is heated to 300-500℃, kept at this temperature for 2-4 hours, and then cooled with the furnace to eliminate welding residual stress.

[0049] Furthermore, in the pretreatment step, a combination of chemical corrosion and mechanical polishing is used. The impeller surface to be welded is first corroded with a nitric acid solution with a mass fraction of 5-10% for 3-5 minutes, and then mechanically polished with sandpaper with a particle size of 800-1200 mesh.

[0050] Furthermore, the fixture adopts an adaptive flexible clamping structure, which can automatically adjust the clamping point and clamping force, and the fixture has a vibration isolation function.

[0051] Furthermore, a high-speed camera is used to collect real-time image information of the molten pool during the welding process, and an image processing algorithm is used to analyze the shape, size and dynamic changes of the molten pool. The parameters of the laser beam are adjusted based on the analysis results.

[0052] Furthermore, after heat treatment, ultrasonic flaw detection and metallographic structure analysis are performed on the weld joints, and repair welding is performed on the defective parts.

Claims

1. A deep well pump, comprising a motor (1), wherein the lower end of the motor (1) is connected to a support base (2), the upper end of the motor (1) is connected to a water inlet section (4) via a coupling (3), a multi-stage pump housing (5) is sleeved on a pump shaft (6) and fixed downstream of the water inlet section (4), a multi-stage impeller guide vane assembly is mounted on the pump shaft (6) and located within the multi-stage pump housing (5), and a water outlet section (7) is mounted downstream of the multi-stage pump housing (5); and characterized in that: The multi-stage impeller guide vane assembly comprises an impeller (8) and a guide vane (9); a groove (81) is provided on the radial end face of the hub inlet of the impeller (8); an end face convex ring (91) and a flow channel side convex ring (92) are provided on the radial end face of the hub outlet of the guide vane (9), wherein the end face convex ring (91) is clearance-matched with the groove (81), and the flow channel side convex ring (92) is abutted against the flow channel side hub face of the impeller (8); a through drainage groove (82) is provided on the outlet end side of the impeller (8), a guide vane (83) is radially provided in the drainage groove (82), a through jet groove (93) is provided on the inlet end side of the guide vane (9), a guide ring (94) is provided in the jet groove (93), an axial center line of the drainage groove (82) is collinear with an axial center line of the jet groove (93), and the axial center line points to the outlet position of the guide vane (9).

2. A deep well pump according to claim 1, characterized in that: Both ends of the guide vane (83) are movably mounted on the groove wall surface of the drainage groove (82) via a short shaft.

3. A deep well pump according to claim 1, characterized in that: The cross section of the guide ring (94) is triangular, and the guide ring (94) is installed on the outlet side of the jet flow groove (93).

4. A deep well pump according to claim 1, characterized in that: The impeller (8) comprises a first blade (84) and a second blade (87), wherein the second blade (87) is fixed to the outlet end of the first blade (84) via a connecting plate (86).

5. A deep well pump according to claim 4, characterized in that: The first blade (84) is installed between the impeller (8) hub and the impeller cover (85), and a buffer gap exists between the second blade (87) and the first blade (84), the impeller (8) hub and the impeller cover (85).

6. A deep well pump according to claim 5, characterized in that: The radial length of the second blade (87) is L1, and the radial width of the inlet flow passage of the guide vane (9) is L2, wherein 0.3L2≤L1<0.8L2.

7. A deep well pump according to claim 6, characterized in that: The second blade (87) is a straight blade.

8. A multi-beam laser welding method for an impeller, wherein the impeller is an impeller of a deep well pump according to any one of claims 1 to 7, characterized in that: The following steps are involved: Pre-treat all parts of the impeller to be welded to remove surface impurities and oil stains to ensure a clean welding surface; Fix the impeller parts to be welded on the welding fixture, and adjust the impeller position through the fixture to ensure the impeller position is stable during the welding process; At least three laser beams are used to act simultaneously on the impeller portion to be welded, wherein one main laser beam is incident vertically to the welding portion, and the remaining auxiliary laser beams are incident at an angle of 10° to 30° to the main laser beam; During the welding process, the energy distribution and pulse frequency of each laser beam are adjusted in real time according to the material and thickness of the impeller. At the same time, the deformation of the impeller is monitored in real time through a high-precision displacement sensor. When the deformation exceeds the preset threshold, the energy input of the laser beam and the welding speed are automatically adjusted through feedback. After welding is completed, the welded joint is heat treated. The welded impeller is heated to 300-500℃, kept at this temperature for 2-4 hours, and then cooled with the furnace to eliminate welding residual stress.

9. The multi-beam laser welding method for an impeller according to claim 8, characterized in that: In the pretreatment step, a combination of chemical corrosion and mechanical grinding is used. The impeller surface to be welded is first corroded with a nitric acid solution with a mass fraction of 5-10% for 3-5 minutes, and then mechanically ground with sandpaper with a particle size of 800-1200 mesh.

10. The multi-beam laser welding method for an impeller according to claim 8, characterized in that: The fixture adopts an adaptive flexible clamping structure, which can automatically adjust the clamping point and clamping force, and the fixture has vibration isolation function.

11. The multi-beam laser welding method for an impeller according to claim 8, characterized in that: A high-speed camera is used to collect real-time image information of the molten pool during the welding process. The shape, size and dynamic changes of the molten pool are analyzed using image processing algorithms, and the parameters of the laser beam are adjusted based on the analysis results.

12. The multi-beam laser welding method for an impeller according to claim 8, characterized in that: After heat treatment, the weld joints are subjected to ultrasonic testing and metallographic analysis, and defective areas are repaired by welding.

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