Novel dry type axial flow pump structure

Abstract

The utility model relates to a novel dry-type axial flow pump structure which comprises a horizontally-split suction chamber, and the suction chamber comprises an independent suction chamber lower portion and an independent suction chamber upper portion. The lower part and the upper part form a complete suction chamber, a front guide vane is arranged in the suction chamber, and the water guide flow rotating direction of the front guide vane is opposite to the rotating direction of the impeller; the front guide vane hub is made into a sliding bearing seat, and a rib plate of the sliding bearing seat is designed into a front guide vane; a self-lubricating sliding bearing is arranged between the sliding bearing seat and the pump shaft; and the bearing seat and the impeller hub are integrally streamlined. Compared with an original axial flow pump structure, the axial flow pump has the advantages of being low in improvement cost, stable in operation, convenient to install and maintain and the like while improving a hydraulic structure. The novel structure is beneficial to eliminating the outflow circulation of the impeller, improving the lift and efficiency of the pump, and increasing the self-lubricating sliding bearing which is a fulcrum close to the impeller, so that the rigidity of the rotor is enhanced, the pump runs more stably, the service life of the water pump is prolonged, and the user experience is improved.

Description

Technical Field

[0001] The utility model relates to a dry axial flow pump, in particular to a novel dry axial flow pump structure with high hydraulic efficiency, stable operation and convenient installation. Background Art

[0002] The dry axial flow pump has the characteristics of large flow, compact structure, small axial size and easy installation.

[0003] Existing dry axial flow pumps have a compact structure to control costs. The motor and pump share a common shaft, which shortens the axial dimensions of the pump head and bearing unit. This results in the design of the product without guide vanes because the guide vane flow path after the impeller outlet is obstructed by the shaft. In addition, the curvature radius of the outlet elbow is too small, resulting in significant water loss. At the same time, the coaxial design reduces the stiffness of the long shaft and increases the deflection at the blades, affecting the stable operation of the pump. In order to improve the efficiency and operational stability of the pump, reduce the operating costs of water conservancy projects, improve the customer experience, and enhance market competitiveness, it is necessary to optimize the structure of the existing dry axial flow pump. Proposing a new axial flow pump structure that is efficient, stable, and easy to install is of great practical significance. Utility Model Content

[0004] In view of the above problems, the main purpose of the present invention is to provide a new dry axial flow pump structure with high hydraulic efficiency, stable operation and convenient installation.

[0005] The utility model solves the above technical problems through the following solutions: a novel dry axial flow pump structure, the novel dry axial flow pump structure comprising: a horizontally split suction chamber, the suction chamber comprising an independent suction chamber lower part and an independent suction chamber upper part; the independent suction chamber lower part and the independent suction chamber upper part constitute a complete suction chamber, a front guide vane is provided in the suction chamber, the water flow rotation direction of the front guide vane is opposite to the rotation direction of the impeller; the front guide vane hub is made into a sliding bearing seat, and the rib plate of the sliding bearing seat is designed as a front guide vane; a self-lubricating sliding bearing is provided between the sliding bearing seat and the pump shaft.

[0006] In a specific implementation example of the present invention, the outer ring of the self-lubricating sliding bearing is interference-fitted with the inner hole of the sliding bearing seat of the suction chamber, and the inner ring of the self-lubricating sliding bearing is clearance-fitted with the pump shaft.

[0007] In a specific implementation example of the present invention, a labyrinth seal is provided on the dividing surface between the lower part of the independent suction chamber and the upper part of the independent suction chamber. The dividing surface is sealed with green shell paper during installation, and the lower part of the independent suction chamber and the upper part of the independent suction chamber are connected with bolts.

[0008] In a specific implementation example of the present invention, front guide vanes are provided on the lower portion of the independent suction chamber and the upper portion of the independent suction chamber, and the front guide vanes are integrated with the wall surface of the suction chamber.

[0009] In a specific implementation example of the present utility model, an impeller locking nut for positioning the impeller hub is provided between the sliding bearing seat and the impeller hub of the novel dry axial flow pump structure, and the impeller locking nut is sleeved on the pump shaft.

[0010] In a specific implementation example of the present invention, the sliding bearing seat and the impeller hub are combined into a streamlined structure that reduces hydraulic impact loss in the suction chamber.

[0011] In a specific implementation example of the present invention, the number of the front guide vanes provided in the suction chamber is 5 to 9, which are evenly arranged in the circumferential direction.

[0012] In a specific implementation example of the present invention, the number of blades is 7.

[0013] In a specific embodiment of the present invention, the inner diameter D3 of the self-lubricating sliding bearing is the shaft diameter D2 of the impeller in the new dry axial flow pump structure minus (5 to 15) mm.

[0014] In a specific implementation example of the present invention, the center of the inner hole of the sliding bearing seat in the horizontal direction is consistent with the center of the front guide vane, and the inner hole of the bearing seat limits the self-lubricating sliding bearing in the horizontal direction. The inner hole diameter of the limiting part is smaller than the inner hole diameter of the bearing seat, and the difference L4 is 5 to 10 mm. After limiting, the sliding bearing and the inner hole of the bearing seat are clearance-matched in the horizontal direction.

[0015] The positive progress of the present invention is that the novel dry axial flow pump structure provided by the present invention has the following advantages compared with common similar technologies:

[0016] 1. The suction chamber with guide vanes and sliding bearings can be rectified in advance by placing the guide vanes in front of the suction chamber, so that the direction of rotation of the water flow at the suction chamber outlet is opposite to that of the impeller, which helps to eliminate the circulation of the impeller outflow. The effect is better than the structure with the guide vanes placed after the impeller, which improves the pump head and hydraulic efficiency and compensates for the water loss caused by the lack of guide vanes and bends.

[0017] 2. Adding a self-lubricating sliding bearing before the impeller inlet eliminates the need for additional lubricant. This bearing addresses the issue of reduced stiffness caused by excessive shaft length in coaxial structures. Furthermore, by adding a fulcrum close to the impeller (the fulcrum is the sliding bearing 3 in the suction chamber), shaft stiffness is increased, allowing for a reduced shaft diameter. This also reduces the size of the corresponding sleeve, mechanical seal, and rolling bearing unit. Compared to the additional structural components in the suction chamber, this reduces the overall pump cost while ensuring more stable rotor operation.

[0018] 3. The new suction chamber adopts a horizontal split type, which makes the pump easy to disassemble and assemble when maintaining the sliding bearing at the customer's site;

[0019] 4. After optimizing the structure, the impeller installation was changed from positioning the impeller pressure plate at the shaft end to positioning the impeller lock nut through the shaft, reducing the requirements for the shaft diameter. At the same time, the original guide shell can be moved to merge with the sliding bearing seat. In this way, the overall structure of the sliding bearing seat and impeller hub is more streamlined and resembles a bullet, reducing hydraulic impact losses in the suction chamber while protecting the sliding bearing.

[0020] 5. The new axial flow pump structure improves the hydraulic performance while ensuring the rotor stiffness. The front guide vane hub is made into a sliding bearing seat, and the rib plate of the sliding bearing seat is designed as a front guide vane. The two are cleverly combined, and the shaft system can also be reduced in size, with low modification costs and convenient disassembly and assembly, thereby improving product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram (cross-sectional view) of the assembly of the new dry axial flow pump proposed in this utility model.

[0022] Figure 2 It is a three-dimensional front view of the suction chamber parts (middle section) in the present invention.

[0023] Figure 3 It is a side view (cross-sectional view) of the suction chamber parts in the present invention.

[0024] Figure 4 This is a schematic diagram of the assembly of the dry axial flow pump prototype before improvement (cross-section view).

[0025] Figure 1-4 Middle: independent suction chamber lower part 1, pump shaft 2, self-lubricating sliding bearing 3, independent suction chamber upper part 4, impeller locking nut 5, impeller 6, shaft sleeve 7, pump body 8, guide casing 9, impeller pressure plate 10, labyrinth seal 11, front guide vane 12, split surface 13, sliding bearing seat 4-1, impeller hub 6-1, integrated suction chamber-impedera chamber 8-1. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to illustrate the technical solutions of the present invention in detail.

[0027] Figure 1 This is a schematic diagram (section view) of the assembly of the new dry axial flow pump proposed in this utility model. Figure 2 This is a three-dimensional front view of the suction chamber part (middle section) in the utility model. Figure 3 This is a side view (sectional view) of the suction chamber parts in the present invention, as shown in FIG. Figure 1-3As shown: The novel dry axial flow pump structure proposed in the present invention includes: a horizontally split suction chamber, comprising an independent suction chamber lower portion 1 and an independent suction chamber upper portion 4 (sliding bearing seat 4-1); the independent suction chamber lower portion 1 and the independent suction chamber upper portion 4 form a complete suction chamber, and the suction chamber is provided with a front guide vane 12, the water flow rotation direction of the front guide vane being opposite to the rotation direction of the impeller; the front guide vane hub is formed into a sliding bearing seat 4-1, and the rib plate of the sliding bearing seat is designed as a front guide vane; a self-lubricating sliding bearing 3 is provided between the sliding bearing seat 4-1 and the pump shaft 2. The outer ring of the self-lubricating sliding bearing 3 has an interference fit with the inner hole of the sliding bearing seat 4-1 in the suction chamber, and the inner ring of the self-lubricating sliding bearing 3 has a clearance fit with the pump shaft 2.

[0028] Both the independent suction chamber lower portion 1 and the independent suction chamber upper portion 4 are provided with pre-guide vanes, which are integral with the suction chamber wall. An impeller locking nut 5 for positioning the impeller hub is provided between the sliding bearing seat 4-1 and the impeller hub 6-1 of the novel dry axial flow pump structure. The impeller locking nut 5 is mounted on the pump shaft 2.

[0029] The combined structure of the sliding bearing seat 4-1 and the impeller hub 6-1 is streamlined to reduce hydraulic impact losses in the suction chamber. Reducing inlet water flow impact and increasing rotor stiffness can reduce the shaft diameter, thereby reducing costs. The suction chamber with guide vanes and sliding bearings in this utility model separates the suction chamber from the original integrated suction chamber and impeller chamber 8-1 structure. Based on actual conditions, the axial length is extended to add front guide vanes and sliding bearing seats. The front guide vanes also serve as ribs to support the bearing seat. The new suction chamber adopts an upper and lower split structure, with a labyrinth seal 11 provided on the mounting surface. During installation, the split surface 13 is sealed with green shell paper. The upper and lower sections are bolted together and then flanged to the impeller chamber.

[0030] Because the sliding bearing is added as a fulcrum, the stiffness of the shaft is significantly improved, so the shaft diameter is reduced by 2 to 3 levels according to actual conditions to optimize the shaft system. The corresponding sizes of the sleeve, mechanical seal, rolling bearing unit, etc. are all reduced to reduce costs.

[0031] The following are specific implementation examples:

[0032] The independent upper suction chamber part 4 and the independent lower suction chamber part 1 in the suction chamber with guide vanes and sliding bearings adopt an upper and lower split structure, such as Figure 2 and Figure 3A labyrinth seal 11 is provided on the dividing surface 13, and the dividing surface is sealed with green shell paper during installation. The upper and lower parts are connected with bolts and then connected to the runner chamber flange. In the new structure, the suction chamber is separated by axially lengthening the original integrated suction chamber-runner chamber 8-1 structure by (0.7~0.9)L1 (L1 is the axial length of the impeller blade edge). The length L2 of the new suction chamber is (1.2~1.5)L1, and 1.4L1 is recommended. The new suction chamber is provided with a front guide vane, with 5 to 9 blades, evenly distributed in the circumferential direction, and 7 blades are recommended. The axial length L3 of the guide vane is (0.8~1.0)L1, and 0.85L1 is recommended. The specific hydraulic angle parameters of the guide vane are determined by matching the actual impeller to ensure that the fluid enters the front guide vane horizontally for rectification and then rotates out. The rotation direction is opposite to the impeller rotation direction, so as to help eliminate the impeller outflow circulation. The inner diameter D4 of the suction chamber remains the same as the original structure.

[0033] The hub of the front guide vanes is equipped with a sliding bearing seat hole. The sliding bearing seat 4-1 is connected to the suction chamber outer casing using the front guide vanes as ribs to ensure the reliability of the sliding bearing seat. The inner diameter D3 of the self-lubricating sliding bearing is D2-(5-15) mm (D2 is the impeller shaft diameter). The specific sliding bearing is determined in accordance with the standard. The center of the sliding bearing seat inner hole is aligned with the center of the front guide vanes in the horizontal direction. The inner hole of the bearing seat limits the self-lubricating sliding bearing in the horizontal direction. The inner hole diameter of the limiting part is smaller than the inner hole diameter of the bearing seat. The difference L4 is 5-10 mm, with 5 mm recommended. After the limit, the sliding bearing has a horizontal clearance fit with the inner hole of the bearing seat. The outer ring of the self-lubricating sliding bearing has an interference fit with the inner hole of the sliding bearing seat, and the inner ring has a clearance fit with the shaft. When replacing the sliding bearing for maintenance, only the split suction chamber needs to be removed, without removing the pump head and piping. This makes disassembly and assembly convenient and reduces maintenance costs.

[0034] By adding a sliding bearing as a fulcrum, the shaft is appropriately extended toward the pump inlet, with the end vertically aligned with the inlet edge of the pre-guide vane. This significantly improves shaft stiffness. Therefore, the shaft diameter of a series of components, such as D1, is reduced by two or three steps, depending on actual conditions, to optimize the shafting. The specific reduction will be determined after verifying rotor stiffness. Consequently, the dimensions of the sleeve, mechanical seal, and rolling bearing unit are all reduced, reducing costs.

[0035] The impeller is installed from the shaft end impeller pressure plate 10 (see Figure 4 ) positioning has been changed to through-shaft installation and impeller locking nut 5 positioning. The optimized new shaft eliminates the impeller pressure plate mounting hole, reducing the shaft diameter requirement. The new impeller eliminates the mounting hole of the original guide casing 9. The guide casing has been moved to integrate with the sliding bearing seat. The sliding bearing seat and impeller hub 6-1 have a bullet-like overall shape, with a more streamlined structure, reducing suction chamber hydraulic impact losses. The labyrinth seals on the upper and lower mounting surfaces of the sliding bearing seat make the bearing seat guide head appear to be one piece, better protecting the sliding bearing from water impact.

[0036] In the specific implementation examples of the present invention, all the above parameters can be adjusted according to actual needs.

[0037] Through the above optimized design, the present invention improves the hydraulic structure while offering advantages over the original axial-flow pump structure, such as low modification cost, stable operation, and easy installation and maintenance. The new structure helps eliminate impeller outflow annularity, increasing pump head and efficiency. The addition of a self-lubricating sliding bearing, a fulcrum close to the impeller, enhances rotor rigidity and more stable pump operation, thereby increasing pump lifespan and improving user experience, thereby strengthening the market competitiveness of dry axial-flow pumps.

[0038] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrative purposes. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements shall fall within the scope of the present invention as claimed, and the scope of protection claimed by the present invention shall be defined by the appended claims and their equivalents.

Claims

1. A new type of dry axial flow pump structure, characterized by: The novel dry axial flow pump structure includes: a horizontally split suction chamber, the suction chamber including an independent suction chamber lower part and an independent suction chamber upper part; the independent suction chamber lower part and the independent suction chamber upper part constitute a complete suction chamber, the suction chamber is provided with a front guide vane, and the water flow rotation direction of the front guide vane is opposite to the rotation direction of the impeller; the front guide vane hub is made into a sliding bearing seat, and the rib plate of the sliding bearing seat is designed to be a front guide vane; a self-lubricating sliding bearing is provided between the sliding bearing seat and the pump shaft.

2. The novel dry axial flow pump structure according to claim 1 is characterized in that: The outer ring of the self-lubricating sliding bearing is interference-fitted with the inner hole of the sliding bearing seat of the suction chamber, and the inner ring of the self-lubricating sliding bearing is clearance-fitted with the pump shaft.

3. The novel dry axial flow pump structure according to claim 1 or 2, characterized in that: A labyrinth seal is provided on the dividing surface between the lower portion of the independent suction chamber and the upper portion of the independent suction chamber. The dividing surface is sealed with green shell paper during installation. The lower portion of the independent suction chamber and the upper portion of the independent suction chamber are connected with bolts.

4. The novel dry axial flow pump structure according to claim 1 is characterized in that: The lower part of the independent suction chamber and the upper part of the independent suction chamber are both provided with front guide vanes, and the front guide vanes are integrated with the wall surface of the suction chamber.

5. The novel dry axial flow pump structure according to claim 1 or 2 is characterized in that: An impeller locking nut for positioning the impeller hub is arranged between the sliding bearing seat and the impeller hub of the novel dry axial flow pump structure, and the impeller locking nut is sleeved on the pump shaft.

6. The novel dry axial flow pump structure according to claim 5 is characterized in that: The integral body of the sliding bearing seat and the impeller hub is streamlined to reduce the hydraulic impact loss in the suction chamber.

7. The novel dry axial flow pump structure according to claim 1 is characterized in that: The number of blades of the front guide vane arranged in the suction chamber is 5 to 9, and they are evenly arranged in the circumferential direction.

8. The novel dry axial flow pump structure according to claim 7 is characterized in that: The number of leaves is 7.

9. The novel dry axial flow pump structure according to claim 1 is characterized in that: The inner diameter D3 of the self-lubricating sliding bearing is the shaft diameter D2 of the impeller in the new dry axial flow pump structure minus (5 to 15) mm.

10. The novel dry axial flow pump structure according to claim 1 is characterized in that: In the horizontal direction, the center of the inner hole of the sliding bearing seat is consistent with the center of the front guide vane, and the inner hole of the bearing seat limits the horizontal direction of the self-lubricating sliding bearing. The inner hole diameter of the limiting part is smaller than the inner hole diameter of the bearing seat, and the difference L4 is 5 to 10 mm. After the limitation, the horizontal clearance of the sliding bearing and the inner hole of the bearing seat is matched.

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