Double-suction pump inlet flow guide elbow structure

Abstract

The utility model relates to a kind of double-suction pump inlet flow guide elbow structure, the structure is installed between flow guide elbow inlet flange and flow guide elbow outlet flange, the structure includes: elbow body, elbow body is built into the flow guide baffle that will be bent pipe inside original flow passage be divided into two flow passages, the appearance of flow guide baffle is generally concave flaky structure, vertically arranged along the pipe diameter center line of elbow;Flow guide baffle one end is flush with flow guide elbow inlet flange, the other end is flush with flow guide elbow outlet flange;Elbow body and flow guide baffle are integrally cast or integrally welded.The utility model both sides even water inlet, solve the single-sided water inlet too large double-suction pump single-sided impeller cavitation problem, avoid impeller cavitation damage;The utility model makes that double-suction pump impeller both sides axial water thrust be balanced, reduces bearing axial load;The utility model water flow is guided through three-dimensional baffle, avoid the inlet turbulent flow phenomenon of original elbow, inlet flow state is stable, water loss is small, and water inlet noise is small.

Description

Technical Field

[0001] This utility model relates to a bent pipe structure, specifically a double-suction pump inlet guide bent pipe structure that can effectively avoid cavitation problems caused by excessive water intake on one side of a double-suction pump. Background Technology

[0002] Double-suction pumps are widely used in various industries such as steel, chemical, and water. Their inlet and outlet pipelines are required to be straight in and out as much as possible. However, some pump rooms have limited space or are restricted by the location of the inlet pool, so horizontal bends are used for the pump inlet and outlet. Due to the inertia of the water itself, less water enters the inner side of the double-suction pump impeller bend and more water enters the outer side of the impeller bend. This leads to cavitation on one side of the pump and an imbalance of axial forces on both sides of the impeller, which accelerates bearing wear. Utility Model Content

[0003] To address the aforementioned problems, the main objective of this utility model is to provide a double-suction pump inlet guide bend structure that can effectively avoid cavitation problems caused by excessive water intake on one side of the double-suction pump.

[0004] To address the issues of unilateral cavitation and axial force imbalance caused by the inlet bend, this utility model patent provides an inlet guide bend structure for a double-suction pump. This structure can uniformly guide incoming water to both sides of the impeller inlet of the double-suction pump, making it suitable for various inlet positions and easy to arrange in compact spaces.

[0005] The structural feature is that a baffle is built into the bend, which divides the original flow channel into two channels. The baffle adopts a three-dimensional twisted structure. The geometry of the baffle is designed using CFD and optimized through simulation. The baffle is welded to the bend or cast integrally. The baffle starts at the bend's starting point and ends at the bend's ending point. The bend is connected to the inlet pipe and the pump inlet flange through a flange. The guide bend can be made into a variable diameter guide bend according to the pipe and pump inlet flange size, or it can be designed into a guide bend with different curvatures.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution: a double-suction pump inlet guide bend structure, wherein the double-suction pump inlet guide bend structure is installed between the guide bend inlet flange and the guide bend outlet flange.

[0007] The double-suction pump inlet guide bend structure includes: a bend body, the bend body having a built-in guide baffle that divides the original flow channel inside the bend into two flow channels, the guide baffle having an overall concave sheet-like structure and being arranged vertically along the center line of the bend's diameter; one end of the guide baffle is flush with the inlet flange of the guide bend, and the other end is flush with the outlet flange of the guide bend; the bend body and the guide baffle are cast as one piece or welded as one piece.

[0008] In a specific implementation of this utility model: both the inlet flange and the outlet flange of the guide bend use standard flanges, which are connected to the inlet pipeline and pump respectively by bolts and gaskets.

[0009] In a specific embodiment of this utility model: the thickness of the water inlet portion of the flow guide baffle gradually changes along the fluid direction, with the inlet end being thinner and gradually thicker, and the middle being the thickest, while the outlet end is thicker and gradually thinner, with the inlet end and the outlet end having the same thickness.

[0010] In a specific embodiment of this utility model, the thickness range of the inlet and outlet ends is 15-25mm, and the thickest part in the middle is 5-10mm thicker than the inlet and outlet ends.

[0011] In a specific embodiment of this utility model, the cross-section of the thickest part in the middle is offset inward by 20-40mm.

[0012] The positive and progressive effects of this utility model are as follows: The double-suction pump inlet guide bend structure provided by this utility model has the following advantages:

[0013] 1. Uniform water intake on both sides solves the problem of cavitation on one side of the impeller in double-suction pumps due to excessive water intake on one side, thus avoiding impeller cavitation damage;

[0014] 2. Uniform water intake from both sides balances the axial water thrust on both sides of the double-suction pump impeller, reducing the axial load on the bearings and extending their service life.

[0015] 3. Water inlet guidance: The water flow is guided by a three-dimensional baffle, avoiding the turbulent flow phenomenon at the inlet of the original bend. The inlet flow is stable, close to horizontal flow, with small hydraulic loss and low water inlet noise.

[0016] 4. Pump operating noise is reduced, pipeline stress is reduced, and unit vibration is reduced;

[0017] 5. Stable water intake and increased pump flow ensured production needs were met;

[0018] 6. This stabilizes the internal flow of the water pump, improves efficiency, and reduces the unit's power consumption. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the installation location of this utility model.

[0020] Figure 2 This is a three-dimensional view of the overall structure of the guide bend proposed in this utility model.

[0021] Figure 3-1 This is one of the three-dimensional views of the flow guide baffle in this utility model.

[0022] Figure 3-2 This is the second three-dimensional view of the flow guide baffle in this utility model.

[0023] Figure 3-3 This is the third three-dimensional view of the flow guide baffle in this utility model.

[0024] Figure 4-1 This is a schematic diagram of the inlet cross-section of the flow guide baffle in this utility model.

[0025] Figure 4-2 This is a schematic diagram of the front section of the flow guide baffle in this utility model.

[0026] Figure 4-3 This is a schematic diagram of the middle section of the flow guide baffle in this utility model.

[0027] Figure 4-4 This is a schematic diagram of the rear section of the flow guide baffle in this utility model.

[0028] Figure 4-5 This is a schematic diagram of the outlet cross-section of the flow guide baffle in this utility model.

[0029] The following are the names corresponding to the reference numerals in this utility model:

[0030] In the diagram: 1. Bending pipe body; 2. Baffle plate; 3. Inlet flange of the bending pipe; 4. Outlet flange of the bending pipe; 5. Double suction pump. Detailed Implementation

[0031] The preferred embodiments of this utility model are given below with reference to the accompanying drawings to illustrate the technical solution of this utility model in detail.

[0032] To address the issues of unilateral cavitation and axial force imbalance caused by the inlet bend, this invention provides an inlet guide bend structure for a double-suction pump. This structure can uniformly guide incoming water to both sides of the impeller inlet of the double-suction pump, making it suitable for various inlet positions and easy to arrange in compact spaces.

[0033] This invention incorporates a baffle plate within a bend, dividing the original flow channel into two channels. The baffle plate employs a three-dimensional twisted structure, with its geometry designed using CFD and optimized through simulation. The baffle plate is welded to or integrally cast with the bend. The baffle plate begins at the bend's starting point and ends at its bend's ending point. The bend is connected to the inlet pipe and the pump inlet flange via flanges. The guide bend can be made into a variable-diameter guide bend according to the pipe and pump inlet flange dimensions, or it can be designed into guide bends with different curvatures.

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention, as shown below. Figure 1As shown: This utility model incorporates a baffle plate within the bend, dividing the original flow channel into two channels. The baffle plate employs a three-dimensional twisted structure, with its geometry designed using CFD and optimized through simulation. The baffle plate is welded to or integrally cast with the bend. The baffle plate begins at the bend's starting point and ends at its bend's ending point. The bend is connected to the inlet pipe and the pump inlet flange via flanges. The guide bend can be made into a variable-diameter guide bend according to the pipe and pump inlet flange dimensions, or it can be designed into guide bends with different curvatures.

[0035] Below are specific examples: Figure 1 As shown, the double-suction pump inlet guide bend structure is installed between the guide bend inlet flange 3 and the guide bend outlet flange 4. The double-suction pump inlet guide bend structure includes: bend body 1, bend body 1 has a built-in guide baffle 2 that divides the original flow channel inside the bend into two flow channels. The guide baffle 2 has an overall concave sheet-like structure and is arranged vertically along the center line of the bend's diameter. One end of the guide baffle 2 is flush with the guide bend inlet flange 3, and the other end is flush with the guide bend outlet flange 4. The bend body 1 and the guide baffle 2 are cast as one piece or welded as one piece.

[0036] Both the inlet flange 3 and outlet flange 4 of the guide bend use standard flanges and are connected to the inlet pipeline and pump respectively by bolts and gaskets. In the specific implementation of this utility model, the connection method between the guide baffle and the bend is determined according to the size of the bend; for small diameters, a cast integral type is selected, and for large diameters, welding is selected.

[0037] In practical implementation, the thickness of the inlet portion of the flow guide baffle in this invention gradually changes along the fluid direction, from thin at the inlet end to thickest in the middle, and from thickest at the outlet end to thinner, with the inlet and outlet ends having the same thickness. The thickness range of the inlet and outlet ends is 15-25mm, with the thickest part in the middle being 5-10mm thicker than both the inlet and outlet ends, and the cross-section of the thickest part in the middle offset inward by 20-40mm (see [reference]). Figure 3-1 (The distance between lines A and B in the diagram).

[0038] This invention solves the problem of uneven water intake caused by the lack of baffles in traditional inlet bends. At the same time, the baffles are hydraulically designed and simulated using CFD software, and are not simple two-dimensional straight baffles, but more closely resemble the actual three-dimensional flow field, reducing eddies and backflow.

[0039] Figure 4-1 This is a schematic diagram of the inlet cross-section of the flow guide baffle in this utility model. Figure 4-2 This is a schematic diagram of the front section of the flow guide baffle in this utility model. Figure 4-3 This is a schematic diagram of the middle section of the flow guide baffle in this utility model. Figure 4-4 This is a schematic diagram of the rear section of the flow guide baffle in this utility model. Figure 4-5This is a schematic diagram of the outlet cross-section of the flow guide baffle in this utility model. As shown in the figure above: the thickness of the inlet portion of the baffle gradually changes along the fluid direction, being thinner at the inlet end and the outlet end, and thickest in the middle. The flow guide baffle has a three-dimensional twisted structure, not a simple two-dimensional straight baffle, which can evenly divide the incoming flow into two parts while minimizing hydraulic losses.

[0040] In this invention, the distance by which the partition deviates from the center line in the middle section is greater than that in the front and rear sections, while the inlet and outlet sections do not deviate.

[0041] The inlet and outlet sections use standard flanges, which are connected to the pump and inlet pipe by bolts and gaskets. The connection method between the flow guide baffle and the bend depends on the size of the bend; for small diameters, a cast-in-place design is selected, while for large diameters, welding is selected.

[0042] This utility model solves the problem of uneven water intake caused by the lack of baffles in traditional inlet bends. At the same time, the baffles are hydraulically designed and simulated using CFD software, and are not simple two-dimensional straight baffles, but more in line with the actual three-dimensional flow field, reducing eddies and backflow.

[0043] The guide bend is a combination of a three-dimensional guide baffle and a bend. The water inlet of the baffle has no angle difference with the incoming flow, and the water flows smoothly into the two separated flow channels. The baffle adopts the design concept of blade guide vanes, so that the water flows into the pump cavity suction chamber in an approximately constant and uniform manner after passing through the guide bend.

[0044] Below are two specific examples of the application of this utility model:

[0045] 1. At a chemical plant in Shanxi, the original KQSN700-M14 / 700 double-suction pump was equipped with a 90° welded conventional bend. After 3 to 6 months of use, the water flow rate was seriously insufficient, even though the outlet water pressure basically met the requirements. After adjusting the valves and other measures, the flow rate did not improve. Upon inspection after shutdown, it was found that the impeller and wear ring on the drive end were severely damaged by cavitation, while there were no obvious problems on the non-drive end.

[0046] Following a site survey, the original inlet bend was modified by replacing it with a diversion bend. Based on the site dimensions, the bend was designed to be DN700, taking into account the normal operating flow rate of 4000m. 3 With a flow rate of / h, a custom-designed guide bend was used. The flow divider was connected to the 90° bend by welding. After installation on site, the pump noise was significantly reduced, the water intake of both impellers was balanced, and after one year of operation, the impellers were disassembled without cavitation damage, and the bearing life was more than doubled.

[0047] 2. The second-phase circulating water system of a chlor-alkali plant in Shaoguan, Guangdong Province, is equipped with three DFSS400-13N / 4C pumps (NPSH 5.7m) and one KQSN500-M9 / 587F pump (NPSH 4.5m). The inlet pipes of all three pumps have 90° bends. On site, the three DFSS double-suction pumps showed obvious cavitation noise, and the calculated operating efficiency was only about 62%. In contrast, the KQSN pump had better cavitation performance, did not show cavitation, and had an efficiency close to 80%.

[0048] To address the cavitation phenomenon in three DFSS pumps, a custom-designed guide bend was used to improve the DN500 welded structure. After the modification, the cavitation noise of the DFSS pumps was significantly reduced, and the flow rate increased from the original 1300 m³ / h. 3 / h increased to 1500m 3 / h, accounting efficiency improved to 79%.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection of this utility model as defined by the appended claims and their equivalents.

Claims

1. A double-suction pump inlet guide bend structure, characterized in that: The double-suction pump inlet guide bend structure is installed between the guide bend inlet flange and the guide bend outlet flange. The double-suction pump inlet guide bend structure includes: a bend body, the bend body having a built-in guide baffle that divides the original flow channel inside the bend into two flow channels, the guide baffle having an overall concave sheet-like structure and being arranged vertically along the center line of the bend's diameter; one end of the guide baffle is flush with the inlet flange of the guide bend, and the other end is flush with the outlet flange of the guide bend; the bend body and the guide baffle are cast as one piece or welded as one piece.

2. The double-suction pump inlet guide bend structure according to claim 1, characterized in that: Both the inlet flange and outlet flange of the guide bend use standard flanges and are connected to the inlet pipeline and pump respectively by bolts and gaskets.

3. The double-suction pump inlet guide bend structure according to claim 1 or 2, characterized in that: The thickness of the water inlet section of the flow guide baffle gradually changes along the fluid direction, from thin at the inlet end to thick at the middle, and from thick at the outlet end to thin at the outlet end, with the inlet and outlet ends having the same thickness.

4. The double-suction pump inlet guide bend structure according to claim 3, characterized in that: The thickness ranges from 15 to 25 mm at the inlet and outlet ends, with the thickest part in the middle being 5 to 10 mm thicker than the inlet and outlet ends.

5. The double-suction pump inlet guide bend structure according to claim 4, characterized in that: The cross-section of the thickest part in the middle is offset inward by 20-40mm.

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