A split type inter-stage bushing and a multi-stage center-opening pump using the same

Abstract

The utility model discloses a half formula interstage bushing and multistage middle open pump using it relates to centrifugal pump water conservancy design field. The half formula interstage bushing includes first half bushing, second half bushing, connecting mechanism, metal gasket, and first half bushing and second half bushing are half circular ring respectively, and first half bushing is connected with second half bushing through connecting mechanism half, and metal gasket is set up between the transverse section of first half bushing and the transverse section of second half bushing, to make the inner surface of first half bushing and the inner surface of second half bushing be on same cylindrical surface. Through half formula interstage bushing, can make multistage middle open pump rotor part after dynamic balance need not split can install interstage bushing, and do not influence rotor part's dynamic balance effect.

Description

Technical Field

[0001] This utility model relates to the field of centrifugal pump hydraulic design, specifically a split-stage bushing for multi-stage split-case pumps. Background Technology

[0002] Multistage centrifugal pumps achieve a gradual increase in water pressure through multiple impellers. Each impeller stage has a different chamber and withstands different water pressures than the next stage. Since all impellers are mounted on the same pump shaft, water leakage often occurs between the shaft and the pump casing of adjacent impeller stages. When water leaks from the high-pressure area to the low-pressure area, it results in efficiency loss for the centrifugal pump. Therefore, the gap between the pump casing and the shaft sleeve / interstage retainer (which protects the impeller shaft) should be minimized to reduce leakage. However, this also makes the interstage retainer and pump casing more prone to collisions during operation. Because multistage centrifugal pumps are only supported by bearings at both ends, the interstage retainer has significant deflection, making it easy for the interstage retainer and pump casing to scrape against each other during shaft rotation, potentially leading to pump casing failure over time. Since the pump casing is very expensive, accounting for over 60% of the total pump cost, a cheaper interstage bushing can be installed on the pump casing, allowing friction between the interstage bushing and the interstage retainer. Because interstage bushings and interstage retainers are simple in structure and inexpensive, they can be replaced even if they wear out due to friction.

[0003] According to domestic and international standards, the rotor components of multistage centrifugal pumps must be dynamically balanced before use to eliminate imbalances and prevent malfunctions during operation. The gap between the interstage bushing and the interstage retainer is extremely small, typically less than 1mm. Therefore, it is common practice to not install the interstage bushing before dynamic balancing of the rotor components. After dynamic balancing, some parts are removed, the interstage bushing is installed, and then the remaining parts are installed. However, this method significantly reduces the reliability of the rotor component's dynamic balancing, and the random imbalances caused by the second installation of parts cannot be avoided, nor does it comply with relevant domestic and international standards. Therefore, a new type of interstage bushing is needed to solve the above problems. Utility Model Content

[0004] The purpose of this invention is to provide a split-stage interstage bushing and a multi-stage split-case pump using the same, in order to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a split-stage interstage bushing for a multi-stage split-case pump, characterized in that the split-stage interstage bushing includes a first half-buffer, a second half-buffer, a connecting mechanism, and a metal gasket. The first half-buffer and the second half-buffer are each a semi-circular ring. The first half-buffer and the second half-buffer are connected by a half-connecting mechanism. The metal gasket is disposed between the cross-section of the first half-buffer and the cross-section of the second half-buffer, so that the inner surfaces of the first half-buffer and the second half-buffer are on the same cylindrical surface.

[0006] Optionally, the connecting mechanism includes: Two grooves are provided on the outer surface of the first half bushing. Each groove corresponds to a cross section of the first half bushing. Between each pair of corresponding grooves and cross sections, a groove surface in the groove that is away from the cross section forms a limiting surface. The limiting surface is parallel to the cross section. The part of the first half bushing located between the limiting surface and the cross section forms a limiting protrusion. Multiple mounting holes are formed on the limiting protrusion and perpendicular to the cross-section; Multiple threaded holes are formed in the second half bushing and the openings are located on the cross section of the second half bushing. The threaded holes correspond one-to-one with the mounting holes. The connecting screws correspond one-to-one with the mounting holes. In each set of corresponding mounting holes, threaded holes and connecting screws, the connecting screws pass through the mounting holes and are threadedly connected to the threaded holes to connect the first half bushing and the second half bushing.

[0007] Optionally, the connecting mechanism further includes: A first pin hole is formed on the limiting protrusion and perpendicular to the cross-section; A second pin hole is formed in the second half bushing and its opening is located on the cross section of the second half bushing; A tapered pin passes through the first pin hole and is inserted into the second pin hole to position and fix the first half bushing and the second half bushing.

[0008] Optionally, the area of ​​the metal gasket is not greater than the area of ​​the cross section of the first half-shear and the second half-shear.

[0009] Optionally, the first half bushing has a groove on its outer arc surface along the circumferential direction, and the groove is located in the middle of the arc surface; the second half bushing has a protrusion on its outer arc surface along the circumferential direction, and the protrusion is located in the middle of the arc surface. The split-stage bushing is fixedly installed inside the pump casing, and the pump casing is provided with limiting protrusions and limiting grooves corresponding to the grooves and protrusions.

[0010] A multistage split-case pump equipped with a split-stage interstage bushing, characterized in that the multistage split-case pump includes a rotor assembly, a pump casing, and a split-stage interstage bushing. The rotor assembly includes a shaft, impellers, interstage bushings, and bearings. There are multiple impellers arranged sequentially along the middle of the shaft. Interstage bushings are arranged between adjacent impellers, and bearings are arranged at both ends of the shaft. The pump casing can be separated by a horizontal plane along the shaft centerline, and the rotor assembly is mounted inside the pump casing via bearings; The split-stage bushing is fixedly installed inside the pump casing, corresponding to the interstage baffle, with a gap between the inner ring of the interstage bushing and the outer ring of the interstage baffle.

[0011] Optionally, the gap should not exceed 1 mm.

[0012] Analysis shows that, compared with the prior art, the advantages and beneficial effects of the present invention are as follows: When the rotor assembly of a multi-stage split-case pump is dynamically balanced, the split-stage bushings are not installed. After the rotor assembly is dynamically balanced, when assembling the whole pump, the split-stage bushings are first disassembled, and then the first and second half bushings are installed in their respective positions on the rotor assembly. The first and second half bushings are positioned and fixed by tapered pins, and finally the connecting screws are tightened to complete the installation. Therefore, the rotor assembly of a multi-stage split-case pump can be equipped with the interstage bushings without disassembly after dynamic balancing, and the dynamic balancing effect of the rotor assembly is not affected. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the split-stage bushing in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a multi-stage split-case pump according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the rotor component of a multi-stage split-case pump according to an embodiment of the present invention; Figure 4 This is a partial schematic diagram of a multi-stage split-case pump equipped with a split-stage bushing, according to an embodiment of the present invention.

[0014] Among them: 1. Split-stage bushing; 11. First half bushing; 12. Second half bushing; 13. Slot; 14. Connecting screw; 15. Tapered pin; 16. Metal gasket; 17. Groove; 18. Protrusion; 2. Rotor assembly; 21. Shaft; 22. Impeller; 23. Interstage retaining sleeve; 24. Bearing; 3. Pump casing. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] It should be noted that in the description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0017] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale.

[0018] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0019] Before understanding this utility model, it is important to understand that the diameter of the impeller 22 of the multi-stage split-case pump is much larger than the diameter of the interstage bushing. Therefore, the interstage bushing needs to be installed before the impeller 22. Since the interstage bushing is not part of the rotor component 2 and there is a gap between it and the interstage retainer 23, installing the interstage bushing on the rotor component 2 affects the dynamic balance of the rotor component 2. If the interstage bushing is installed after the rotor component 2 has been dynamically balanced, it is necessary to disassemble some parts and reassemble the rotor component 2, which will also affect the dynamic balance of the rotor component 2.

[0020] Please refer to Figures 1 to 3 ,in Figure 1 This is a schematic diagram of a split-stage bushing structure; Figure 2 A schematic diagram of the rotor structure of a multi-stage split-case pump; Figure 3 Schematic diagram of a multi-stage split-case pump; Figure 4 A partial schematic diagram of a multistage split-case pump equipped with a split-stage interstage bushing.

[0021] This utility model provides a split-stage interstage bushing 1, which is applied in multi-stage split-case pumps, such as... Figure 1 As shown, it includes a first half-bushing 11, a second half-bushing 12, a connecting mechanism, and a metal gasket 16. The first half-bushing 11 and the second half-bushing 12 are each half of a circular ring. The first half-bushing 11 and the second half-bushing 12 are connected by the connecting mechanism. The metal gasket 16 is disposed between the cross-section of the first half-bushing 11 and the cross-section of the second half-bushing 12. This arrangement ensures that the inner surfaces of the first half-bushing 11 and the second half-bushing 12 are on the same cylindrical surface, and the outer surfaces of the first half-bushing 11 and the second half-bushing 12 are also on the same cylindrical surface.

[0022] Specifically, the connecting mechanism includes: two countersunk grooves 13 disposed on the outer surface of the first half bushing 11, each countersunk groove 13 corresponding to a cross section of the first half bushing 11, and between each set of corresponding countersunk grooves 13 and cross sections, a groove surface in the countersunk groove 13 facing away from the cross section forms a limiting surface, the limiting surface being parallel to the cross section, and a limiting protrusion 18 forming the portion of the first half bushing 11 located between the limiting surface and the cross section; a mounting hole formed in the limiting protrusion 18 and perpendicular to the cross section; multiple threaded holes formed in the second half bushing 12 and opening on the cross section of the second half bushing 12, the threaded holes corresponding one-to-one with the mounting holes; and connecting screws 14 corresponding one-to-one with the mounting holes. In each set of corresponding mounting holes, threaded holes, and connecting screws 14, the connecting screws 14 penetrate the mounting holes and are threadedly connected to the threaded holes to connect the first half bushing 11 and the second half bushing 12.

[0023] The connecting mechanism further includes: a first pin hole formed on the limiting protrusion 18 and perpendicular to the cross section; a second pin hole formed on the second half bushing 12 and with its opening located on the cross section of the second half bushing 12, the first pin hole and the second pin hole corresponding to each other; and a tapered pin 15 passing through the first pin hole and inserted into the second pin hole to position and fix the first half bushing 11 and the second half bushing 12.

[0024] In one embodiment, each recess 13 has two mounting holes 18 at both ends of the limiting surface, and the mounting holes are cylindrical through holes. Correspondingly, there are two threaded holes and two connecting screws 14.

[0025] With the above design, the split-stage bushing 1 is not installed when the rotor component 2 of the multi-stage split pump is dynamically balanced. When the whole pump is assembled after the rotor component 2 is dynamically balanced, the split-stage bushing 1 is first disassembled, and then the first half bushing 11 and the second half bushing 12 are installed in the corresponding positions of the rotor component 2. The first half bushing 11 and the second half bushing 12 are positioned and fixed by the tapered pin 15, and finally the connecting screw 14 is tightened to complete the installation.

[0026] The area of ​​the metal gasket 16 of the split-type interstage bushing 1 is not greater than the area of ​​the cross-section of the first half bushing 11 and the second half bushing 12, so that the split-type interstage bushing 1 is easy to install.

[0027] The first half-bushing 11 has a groove 17 on its outer arc surface along the circumferential direction, located at the center of the arc surface. The second half-bushing 12 has a protrusion 18 on its outer arc surface along the circumferential direction, located at the center of the arc surface. The pump housing 3 has a limiting protrusion 18 and a limiting groove 17 corresponding to the groove 17 and the protrusion 18. This arrangement allows the split-stage bushing 1 to be fixedly installed inside the pump housing 3 and provides a foolproof function.

[0028] This utility model also discloses a multi-stage split-case pump equipped with a split-stage interstage bushing 1, such as... Figure 2 As shown, it includes a rotor assembly 2, a pump casing 3, and a split-stage bushing 1.

[0029] Specifically, the rotor assembly 2 includes a shaft 21, impellers 22, interstage retaining sleeves 23, and bearings 24. Multiple impellers 22 are arranged sequentially along the middle of the shaft 21. Interstage retaining sleeves 23 are positioned between adjacent impellers 22, and bearings 24 are located at both ends of the shaft 21. The pump casing 3 can be separated by a horizontal plane along the shaft centerline, and the rotor assembly 2 is mounted inside the pump casing 3 via bearings 24. A split-stage bushing 1 is fixedly installed within the pump casing 3 at a position corresponding to the interstage retaining sleeve 23, with a gap between the inner ring of the split-stage bushing 1 and the outer ring of the interstage retaining sleeve 23. During operation of the multi-stage split-case pump, the split-stage bushing 1 and the interstage retaining sleeve 23 slide and rub against each other. By installing the split-stage bushing 1 inside the pump casing 3 to allow it to slide and rub against the interstage retaining sleeve 23, the pump casing 3 is protected, preventing wear caused by prolonged scraping. Because the water pressure inside the multistage impeller 22 of the multistage centrifugal pump is different when it is working, in order to avoid water leakage between different cavities, the gap between the half-stage bushing 1 and the stage baffle 23 is no more than 1mm.

[0030] This invention also provides a method for manufacturing a split-stage bushing 1, applicable to the aforementioned manufacturing of the split-stage bushing 1, specifically including: Step S101: Create a countersink 13 for the complete interstage bushing; Step S102: Roughly machine the complete interstage bushing; Step S103: Cut the complete interstage bushing in half to obtain the first part and the second part; Step S104: Fit and fix the first part and the second part together, open a pin hole in the middle of the sinker 13, install the tapered pin 15 in the pin hole to fix the first part and the second part, and open screw holes at both ends in the sinker 13. The screw holes of the first part are through holes and the screw holes of the second part are threaded holes. Step S105: Fabricate metal gasket 16; Step S106: Assemble and install the aforementioned components, and perform precision machining to obtain the split-stage bushing 1.

[0031] This invention also provides a method for installing a split-stage interstage bushing 1, applicable to the installation of the aforementioned split-stage interstage bushing 1 in a multi-stage split-case pump, specifically including: Step S201, the rotor component 2 is dynamically balanced. At this time, the rotor component 2 is not equipped with the split-stage bushing 1. Step S202: Disassemble the split-stage bushing 1, and assemble the multi-stage split-case pump into a whole pump. When installing the split-stage bushing 1, first install the tapered pin 15 for positioning, and then install the screws.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A split-stage interstage bushing for a multi-stage split-case pump, characterized in that, The split-stage bushing includes a first half bushing, a second half bushing, a connecting mechanism, and a metal gasket. The first half bushing and the second half bushing are each a semi-circular ring. The first half bushing and the second half bushing are connected by the connecting mechanism. The metal gasket is disposed between the cross-section of the first half bushing and the cross-section of the second half bushing, so that the inner surfaces of the first half bushing and the second half bushing are on the same cylindrical surface.

2. The split-stage bushing according to claim 1, characterized in that, The connecting mechanism includes: Two grooves are provided on the outer surface of the first half bushing. Each groove corresponds to a cross section of the first half bushing. Between each pair of corresponding grooves and cross sections, a groove surface in the groove that is away from the cross section forms a limiting surface. The limiting surface is parallel to the cross section. The portion of the first half bushing located between the limiting surface and the cross section forms a limiting protrusion. Multiple mounting holes are formed on the limiting protrusion and perpendicular to the cross-section; Multiple threaded holes formed in the second half bushing and with openings located on the cross section of the second half bushing, wherein each threaded hole corresponds to a mounting hole; The connecting screws correspond one-to-one with the mounting holes. In each set of corresponding mounting holes, threaded holes and connecting screws, the connecting screws pass through the mounting holes and are threadedly connected to the threaded holes to connect the first half bushing and the second half bushing.

3. A split-stage bushing according to claim 2, characterized in that, The connecting mechanism further includes: A first pin hole is formed in the limiting protrusion and is perpendicular to the cross-section; A second pin hole is formed in the second half bushing and its opening is located on the cross section of the second half bushing; A tapered pin, which passes through the first pin hole and is inserted into the second pin hole, to position and fix the first half bushing and the second half bushing.

4. A split-stage interstage bushing according to claim 1, characterized in that, The area of ​​the metal gasket is not greater than the area of ​​the cross-section of the first half-shroud and the second half-shroud.

5. A split-stage bushing according to claim 1, characterized in that, The first half-shoulder has a groove on its outer arc surface along the circumferential direction, and the groove is located in the middle of the arc surface; the second half-shoulder has a protrusion on its outer arc surface along the circumferential direction, and the protrusion is located in the middle of the arc surface. The split-stage bushing is fixedly installed inside the pump housing, and the pump housing is provided with limiting protrusions and limiting grooves corresponding to the grooves and protrusions.

6. A multi-stage split-case pump equipped with the split-stage bushing as described in claim 1, characterized in that, The multi-stage split-case pump includes a rotor assembly, a pump casing, and the split-stage bushing. The rotor assembly includes a shaft, impellers, interstage retaining sleeves, and bearings. There are multiple impellers arranged sequentially along the middle of the shaft. The interstage retaining sleeves are arranged between adjacent impellers, and the bearings are arranged at both ends of the shaft. The pump casing can be separated by a horizontal plane along the shaft centerline, and the rotor component is mounted inside the pump casing via the bearing; The split-stage bushing is fixedly installed inside the pump housing, corresponding to the interstage baffle, and a gap is left between the inner ring of the interstage bushing and the outer ring of the interstage baffle.

7. The multi-stage split-case pump according to claim 6, characterized in that, The gap is no greater than 1 mm.

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