Streamline elbow for axial flow pump and production method

Abstract

The invention relates to an elbow for a streamline axial flow pump and a production method, the elbow is a circular elbow formed by punching, forming and welding two fan-shaped blanks, and the elbow is respectively provided with an elbow inner cambered surface and an elbow outer cambered surface; a mechanical seal seat is fixedly arranged on one side of the outer cambered surface of the elbow, a connecting cylinder is sleeved outside the mechanical seal seat, and an outlet pipeline and an inlet pipeline are respectively arranged at two ends of the elbow; the invention relates to a stamping and welding production process for a two-section fan-shaped blank for a pump elbow. Through the working procedures of numerical control blanking, punch forming, assembly welding, heat treatment shaping and the like, a cutting machine is used for cutting a steel plate into two fan-shaped blanks, the blanks are punched into two shells through a press machine, the two shells are assembled and welded to form a complete circular ring elbow, annealing heat treatment is carried out to eliminate stress, and shaping and roundness correction are carried out. The inner surface and the outer surface of the elbow are smooth, vortex and fluid resistance are reduced in a streamline mode, pressure loss is avoided, fluid conveying stability is guaranteed, production weld joints are reduced, corrosion is reduced, and the service life of equipment is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of fluid transportation, and in particular relates to a streamlined elbow for an axial flow pump and its manufacturing method. Background Technology

[0002] Axial flow pumps are low-head, high-flow-rate pumps widely used in salt production, nitrate production, and the chemical industry. They rely on the vortex force generated by the high-speed rotation of an impeller within the pump casing to lift and transport liquids, pushing water from bottom to top. The impeller blades are typically submerged in the water source. Due to the high-speed rotation of the impeller, the lift generated by the blades continuously pushes the water upwards, causing it to flow out through the outlet pipe. As the impeller continues to rotate, water is continuously pumped to a higher level. Therefore, the smoothness of the liquid transported by the elbow in an axial flow pump is extremely important. A smooth, rounded transition in the elbow and a smooth flow path, ensuring unobstructed fluid transport and no pressure loss, are essential to guaranteeing the efficiency of the axial flow pump.

[0003] Current axial flow pump elbows are made of equal-diameter shrimp-shaped welded elbows, which have many welds and are prone to stress and chemical and electrochemical corrosion. The non-circular transition of the flow channel and the unevenness of the welds cause eddies and pressure drops in the fluid, resulting in pump body vibration, noise, increased fluid resistance, and reduced efficiency. Summary of the Invention

[0004] The problem this invention aims to solve is that existing axial flow pump elbows have many weld seams that are prone to electrochemical corrosion, leading to increased fluid resistance and reduced efficiency. The invention provides a streamlined axial flow pump elbow and its manufacturing method. By employing a two-part fan-shaped blank stamping and welding process, the welded elbow has fewer weld seams, resulting in smooth, unobstructed fluid flow, increased axial flow pump efficiency, improved overall pump unit efficiency, and ensured stable media delivery.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a streamlined axial flow pump elbow, wherein the elbow is formed by stamping and welding two fan-shaped blanks into a circular elbow, and the elbow has an inner arc surface and an outer arc surface respectively. The elbow has a fixed mechanical seal seat on one side of its outer arc surface. The mechanical seal seat is fitted with a connecting cylinder. The elbow has an outlet pipe and an inlet pipe at its two ends, respectively. The inlet pipe is connected to a horizontal pipe, and the outlet pipe and the horizontal pipe are respectively fitted with flanges. The inner arc surface of the elbow is fitted with reinforcing ribs and welded with flanges.

[0006] A method for manufacturing a streamlined elbow for an axial flow pump, the specific process flow is as follows: The pump elbow is a large-diameter, non-standard metal stamping elbow, produced by stamping and welding two-lobed fan-shaped blanks. 1) CNC blanking: Based on the unfolded drawing of the non-standard elbow, a special cutting program and mold need to be customized for the non-standard angle. The bending radius R value is determined by the algorithm to unfold the drawing. The steel plate is cut into two fan-shaped blanks using a plasma or laser cutting machine. 2) Stamping: The cut two fan-shaped blanks are placed into the mold of a large press. The mold needs to reserve thickness allowance. During the stamping and stretching process, the outer arc surface metal of the elbow will be stretched, resulting in a wall thickness reduction of 0% to 20%. The inner arc surface metal of the elbow will be compressed and thickened and wrinkled. The two shells are formed by stamping the pressure blank. 3) Assembly and welding: The two pressed shell halves are assembled and aligned on the jig, and welded along the longitudinal seam to form a complete circular elbow with an inlet pipe and an outlet pipe; 4) Heat treatment and shaping: After welding, the elbow needs to be annealed to relieve stress, and then shaped and rounded. The bevels at both ends of the elbow are also machined to facilitate on-site pipeline welding.

[0007] The advantages and positive effects of this invention are: 1. The present invention provides a streamlined elbow for an axial flow pump. The elbow is formed by stamping and welding two fan-shaped blanks into a circular elbow. The elbow has an inner arc surface and an outer arc surface. It is formed in one piece, with a beautiful appearance and good smoothness of the inner and outer surfaces. The smooth and streamlined inner surface reduces fluid resistance while ensuring fluid transport pressure and ensuring the stability of fluid delivery.

[0008] 2. This invention discloses a method for producing streamlined axial flow pump elbows. Since the pump elbows are large-diameter non-standard metal stamped elbows, a two-part fan-shaped blank stamping and welding production process is adopted. Through CNC blanking, stamping, assembly welding, heat treatment and shaping, etc., the smoothness of the inner and outer surfaces of the elbows is achieved, resulting in a streamlined shape that reduces eddies and fluid resistance, avoids pressure loss, reduces production welds, reduces corrosion, and extends the service life of the equipment.

[0009] 3. This invention discloses a method for producing a streamlined axial flow pump elbow. The method employs assembly welding, assembling and aligning the two pressed shell halves on a jig, and welding along the longitudinal seam to form a circular elbow with an outlet pipe and an inlet pipe. This ensures a streamlined flow channel, optimizes the flow channel curvature through fluid dynamics, avoids abrupt changes in direction, reduces eddy generation, and improves the efficiency of liquid flow. The inlet and outlet fluid transitions smoothly, with the inlet using a horizontal pipe connection structure to the elbow, mitigating fluid impact and balancing efficiency and noise reduction. Attached Figure Description

[0010] Figure 1 A schematic diagram of a streamlined elbow structure for an axial flow pump according to the present invention.

[0011] 1-Elbow; 2-Inlet pipe; 3-Inner arc surface of elbow; 4-Reinforcing rib; 5-Horizontal pipe; 6-Outlet pipe; 7-Outer arc surface of elbow; 8-Mechanical seal seat; 9-Connecting cylinder; 10-Flange. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to specific embodiments.

[0013] like Figure 1 As shown, a streamlined axial flow pump elbow is made of large-diameter non-standard metal using two fan-shaped blanks. A customized cutting program and mold are required to determine the development diagram of the non-standard elbow. A plasma or laser cutting machine is used to cut the steel plate into two fan-shaped blanks. A press is used to stamp and weld them into a circular elbow. The elbow 1 has an outlet pipe 6 and an inlet pipe 2 at both ends. The inlet pipe 2 connects to a horizontal pipe 5. The elbow 1 has an inner arc surface 3 and an outer arc surface 7. A mechanical seal seat 8 is fixed to one side of the outer arc surface 7. A connecting cylinder 9 is fitted over the mechanical seal seat 8. Flanges 10 are installed on the outlet pipe 6 and the horizontal pipe 5. Reinforcing ribs 4 are installed on the inner arc surface 3, and flanges 10 are welded to the reinforcing ribs 4.

[0014] A manufacturing process for streamlined axial flow pump elbows, specifically large-diameter non-standard metal stamped elbows 1, employs a two-part fan-shaped blank stamping and welding process. First, two fan-shaped blanks are CNC-cut. For non-standard angles, a customized cutting program and mold are required. Based on the unfolded diagram of the non-standard elbow, the bending radius R is determined using an algorithm. The steel plate is then cut into two fan-shaped blanks using a plasma or laser cutting machine. Next, the cut fan-shaped blanks are placed into the mold of a large press for stamping and forming. During the stamping and stretching process, the bending... The outer arc surface 7 of the elbow is stretched, resulting in a wall thickness reduction of about 10%. The mold needs to reserve a thickness allowance to prevent the inner arc surface 3 of the elbow from thickening and wrinkling due to compression. The two shell halves are formed by pressing the blank. Then, the two shell halves are assembled and aligned on the jig and welded along the longitudinal seam to form a complete elbow 1 with an inlet pipe 2 and an outlet pipe 6. Finally, the elbow 1 after welding needs to be heat-treated to relieve stress and then shaped and rounded. The bevels at both ends of the elbow 1 are machined to facilitate on-site pipe welding.

[0015] During operation, the axial flow pump relies on the vortex force generated by the high-speed rotation of the impeller inside the pump casing to lift and transport the liquid, pushing the water from bottom to top. The impeller blades of the axial flow pump are generally immersed in the water source pool. Due to the high-speed rotation of the impeller, the lift force generated by the blades continuously pushes the water upward, causing it to flow out along the outlet pipe. The liquid enters the horizontal pipe 5 and the inlet pipe 2 through flange 10, and then passes through the arc elbow 1 with the inner arc surface 3 and the outer arc surface 7 of the elbow. The vortex force of the blades lifts and transports the liquid to the outlet pipe 6 and flange 10. Because the inner surface of the elbow 1 is smooth and flat, and has a streamlined shape, the entire process is smooth and the pressure is not reduced, thus ensuring the fluid transport pressure and maintaining the stability of the fluid transport.

[0016] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A streamlined elbow for an axial flow pump, characterized in that: The elbow is formed by stamping and welding two fan-shaped blanks into a circular elbow, and the elbow has an inner arc surface and an outer arc surface. The elbow has a fixed mechanical seal seat on one side of its outer arc surface. The mechanical seal seat is fitted with a connecting cylinder. The elbow has an outlet pipe and an inlet pipe at its two ends, respectively. The inlet pipe is connected to a horizontal pipe, and the outlet pipe and the horizontal pipe are respectively fitted with flanges. The inner arc surface of the elbow is fitted with reinforcing ribs and welded with flanges.

2. The manufacturing method of a streamlined axial flow pump elbow according to claim 1, the specific process flow is as follows: The pump elbow is a large-diameter, non-standard metal stamping elbow, produced by stamping and welding two-lobed fan-shaped blanks. 1) CNC blanking: Based on the unfolded drawing of the non-standard elbow, a special cutting program and mold need to be customized for the non-standard angle. The bending radius R value is determined by the algorithm to unfold the drawing. The steel plate is cut into two fan-shaped blanks using a plasma or laser cutting machine. 2) Stamping: The cut two fan-shaped blanks are placed into the mold of a large press. The mold needs to reserve thickness allowance. During the stamping and stretching process, the outer arc surface metal of the elbow will be stretched, resulting in a wall thickness reduction of 0% to 20%. The inner arc surface metal of the elbow will be compressed and thickened and wrinkled. The two shells are formed by stamping the pressure blank. 3) Assembly and welding: The two pressed shell halves are assembled and aligned on the jig, and welded along the longitudinal seam to form a complete circular elbow with an inlet pipe and an outlet pipe; 4) Heat treatment and shaping: After welding, the elbow needs to be annealed to relieve stress, and then shaped and rounded. The bevels at both ends of the elbow are also machined to facilitate on-site pipeline welding.

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