Double inlet multistage split case centrifugal pump

Abstract

The present invention discloses a dual-inlet multi-stage split-case centrifugal pump, which mainly includes a pump body, a pump cover, an impeller, a secondary double-suction impeller, a bearing support component, a sealing component, a pump shaft, and a sealing ring. The pump body and the pump cover are characterized in that a mixing grid is provided in the transition flow channel within the pump body and the pump cover. The mixing grid separates the transition flow channel into two flow channel cavities along the direction of water flow, so that the water flow with a biased flow vortex entering the transition flow channel is blocked by the mixing grid and the flow velocity is reduced. This significantly reduces the biased flow vortex formed by the suction effect of the impeller, reduces the impact and abrasion of the biased flow vortex on the impeller, the transition flow channel, and the secondary double-suction impeller, and prolongs the service life of the impeller and the pump body, greatly reduces the maintenance frequency, saves the use cost of the pump, and simultaneously reduces the resonance and noise in the pump body, thereby improving the stability of the pump operation.

Description

Technical Field

[0001] The invention relates to the technical field of fluid machinery, in particular to a double-inlet multi-stage split-case centrifugal pump. Background Art

[0002] As we all know, water pumps are an essential and key equipment in the basic links of industrial production equipment. With the development of my country's economy, the application scope of industrial water pumps is becoming wider and wider. Enterprises in the steel, metallurgy, power generation, mining, petroleum, chemical, cement, pharmaceuticals, fertilizers, papermaking and other industries will use centrifugal pumps, circulation pumps and other series of products in large quantities.

[0003] Multistage pumps are used in many industrial sectors, including petroleum, chemical, machinery, mining, light industry, medicine, and food. They are widely used in many industrial processes, such as heating and water supply, boiler feed, seawater desalination, industrial process vacuum technology, metallurgy, phosphorus removal, chemical aeration and feed, and agricultural water conservancy. They can pump flammable and explosive gases, as well as gases containing dust and water. Consequently, their application is increasing.Since the pressure on both sides of the centrifugal pump impeller (3) is not equal when it is running, it is easy to generate corresponding axial thrust. In order to reduce the destructiveness of the axial thrust to the pump structure, a double-inlet multi-stage centrifugal pump with mirror images of the impeller (3) on both sides is often used so that the impeller (3) does not generate axial thrust when it is running. The existing split-center centrifugal pump mainly includes a pump body (1), a pump cover (2), an impeller (3), a secondary double-suction impeller (4), a bearing support component (5), a sealing component (6), a pump shaft (7) and a sealing ring (8). The pump cover (2) is located at the upper end of the pump body (1). The pump cover (2) and the pump body (1) form an inner cavity of the pump body (1). The inner cavity of the pump body (1) includes a suction chamber, a transition flow channel (9) and an extrusion chamber that are connected to each other. A pump shaft (7) is rotatably provided at the center of the inner cavity of the pump body (1). The pump shaft (7) is mirror-imaged from the center to both ends and is provided with a secondary double-suction impeller (4), an impeller (3), a sealing component (6) and a bearing support component. The bearing components (5) are fixedly connected to the pump body (1) at both ends of the pump shaft (7). The sealing components (6) are sealed and connected to the pump body (1) and the pump cover (2). The secondary double-suction impeller (4) is located in the extrusion chamber. The outer ring of the inlet end of the secondary double-suction impeller (4) is rotatably sealed and connected to the pump body (1) and the pump cover (2) via the sealing ring (8). The impeller (3) is located in the suction chamber. The outer ring of the inlet end is rotatably sealed and connected to the pump body (1) and the pump cover (2) via a sealing ring (8). The water inlet end of the transition flow channel (9) is connected to the water outlet end of the impeller (3). The water outlet end of the transition flow channel (9) is connected to the water inlet end of the secondary double-suction impeller (4). The pump shaft (7) is driven by a drive motor. The substantial shortcomings of this structure are: 1. During the rotation of the pump shaft (7), the liquid or two-phase or multi-phase flow moves with the impeller (3). Due to the suction effect, the working medium entering the impeller (3), the transition channel (9) and the secondary double-suction impeller (4) will have a biased flow vortex line phenomenon. The working medium with the biased flow vortex accelerates the impact and abrasion on the transition channel (9) and the secondary double-suction impeller (4) under the action of radial pre-rotation and axial impact, which will shorten their service life and require maintenance and replacement. In addition, the double-suction pump structure is relatively complex and difficult to replace, which greatly increases the use cost of the pump and the manpower investment. At the same time, after the working medium with the biased flow vortex enters the secondary double-suction impeller (4), it interferes with the medium flow state when the inlet section of the secondary double-suction impeller (4) is designed, causing hydraulic loss of the pump. At the same time, the pressure of the working medium at the inlet of the secondary double-suction impeller (4) will also be reduced, and it will make it easier for cavitation to occur at the inlet of the blades of the secondary double-suction impeller (4) and generate resonance and noise during the entire working process, which will also have a great impact on the stable operation of the pump.Second, when conveying liquid, if the liquid contains a large amount of particles or the dissolved matter in the liquid is easy to precipitate crystals, these particles or crystals will often accumulate on the sealing ring (8) during the liquid conveying process, causing the impeller (3) to be stuck or even unable to rotate. In addition, the particles will also wear the sealing ring (8) or the pump body (1), causing the seal to fail and reducing the service life of the pump body (1). Summary of the Invention

[0004] In order to solve the substantial deficiencies of the above-mentioned prior art, the present invention provides a double-inlet multi-stage split centrifugal pump with novel structure, high operating efficiency, high working stability, low use cost, low noise and long working life.

[0005] The technical means adopted by the present invention to solve the above technical problems are:

[0006] A double-inlet multi-stage split-center centrifugal pump mainly comprises a pump body (1), a pump cover (2), an impeller (3), a secondary double-suction impeller (4), a bearing support component (5), a sealing component (6), a pump shaft (7) and a sealing ring (8), characterized in that a mixing grid (10) is provided in a transition flow channel (9) in the pump body (1) and the pump cover (2), wherein the mixing grid (10) separates the transition flow channel (9) into two flow channel cavities along the direction of water flow, so as to facilitate the water flow with a biased flow vortex entering the transition flow channel (9) to be blocked by the mixing grid (10) and reduce the flow velocity, significantly reduce the biased flow vortex formed by the suction effect of the impeller (3), reduce the impact and abrasion of the biased flow vortex on the impeller (3), the transition flow channel (9) and the secondary double-suction impeller (4), extend the service life of the impeller (3) and the pump body (1), greatly reduce the maintenance frequency, save the use cost of the pump, and at the same time, reduce the resonance and noise in the pump body (1). This improves the stability of pump operation.

[0007] The present invention can fix adjacent scrapers (11) and particle holding grooves (12) on the outer ring of the water inlet end of the impeller (3) and / or the outer rings at both ends of the secondary double-suction impeller (4), one end of the particle holding groove (12) extends to the end of the impeller and / or the secondary double-suction impeller, the scrapers (11) and the particle holding grooves (12) are arranged circumferentially, and the outer ends of the scrapers (11) are exposed from the outer ring of the impeller (3) body, so that when in use, the scrapers (11) rotate and scrape off particles on the sealing ring (8), and the particles fall into the particle holding grooves (12) and are washed away by the fluid, thereby avoiding the accumulation or stagnation of particles in the gap between the sealing ring (8) and the impeller (3) during the liquid transportation process, causing the impeller (3) to be stuck in rotation, thereby extending the service life of the sealing ring (8) and significantly improving the working stability.

[0008] The present invention can also symmetrically provide two pairs of rectifying grids (13) at the outlet end of the transition flow channel (9), and the rectifying grids (13) are axially arranged to facilitate the rectifying grids (13) to rectify the fluid mixed by the mixing grid (10) again, thereby further reducing the flow resistance of the fluid, thereby significantly improving the stability of the operation.

[0009] The present invention can also symmetrically provide guide baffles (14) on both sides of the horizontal split position of the transition flow channel (9), and the height and width of the guide baffles (14) gradually decrease in an arc from the outer end toward the pump shaft (7), so as to achieve the purpose of guiding the fluid after the steady flow through the guide baffles (14), thereby improving the operating efficiency and working efficiency of the pump body (1).

[0010] The present invention can also provide an interstage seal (15) between the outlet end of the transition flow channel (9) and the pump shaft (7). The interstage seal (15) is a split structure composed of two half interstage seal bodies (15-1), and the two sides of the two half interstage seal bodies (15-1) are fixedly connected by fixing screws. The outer end of the interstage seal (15) is fixedly connected to the pump body (1) and the pump cover (2) through a positioning pin or a protrusion. Two pairs of rectifying grids (13) are symmetrically provided on one end surface of the interstage seal (15). The rectifying grids (13) are axially arranged to facilitate the rectification of the fluid mixed by the mixing grid (10) through the rectifying grid (13), thereby further reducing the flow resistance of the fluid, so that the stability of the operation is significantly improved.

[0011] The present invention can also symmetrically provide guide baffles (14) on both sides of the horizontally divided position of the interstage seal body (15), wherein the height and width of the guide baffles (14) gradually decrease in an arc from the outer end toward the pump shaft (7), so as to achieve the purpose of guiding the fluid after the flow is stabilized through the guide baffles (14), thereby improving the operating efficiency and working efficiency of the pump body (1).

[0012] The present invention can also provide a labyrinth inner hole in the inner hole of the interstage sealing body (15), and the labyrinth inner hole of the interstage sealing body (15) is sealedly connected to the pump shaft (7) through a sealing ring provided therein, so as to improve the sealing performance of the interstage sealing body (15) and the pump shaft (7) through the labyrinth inner hole.

[0013] Due to the adoption of the above structure, the present invention has the advantages of novel structure, high operating efficiency, high working stability, low use cost, low noise, long working life and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of an embodiment of the present invention.

[0015] Figure 2It is a three-dimensional schematic diagram of the mixing position of the transition channel.

[0016] Figure 3 This is the main view of the interstage seal.

[0017] Figure 4 yes Figure 3 Left view of .

[0018] Figure 5 It is the hydraulic diagram of the transition channel.

[0019] Figure 6 It is a structural schematic diagram of another embodiment of the present invention.

[0020] Figure 7 yes Figure 6 A partial enlarged view of middle A.

[0021] Figure 8 yes Figure 7 Schematic diagram of the structure of the scraper and particle holding groove in the B direction.

[0022] Reference numerals: pump body (1), pump cover (2), impeller (3), secondary double-suction impeller (4), bearing support component (5), sealing component (6), pump shaft (7), sealing ring (8), transition flow channel (9), mixing grid (10), scraper (11), particle holding groove (12), rectifying grid (13), guide baffle (14), interstage seal (15), semi-interstage seal body (15-1). DETAILED DESCRIPTION

[0023] The present invention will be described below with reference to the accompanying drawings and embodiments.

[0024] As attached Figure 1 、 2As shown in , 5, a double-inlet multi-stage split centrifugal pump mainly includes a pump body (1), a pump cover (2), an impeller (3), a secondary double-suction impeller (4), a bearing support component (5), a sealing component (6), a pump shaft (7) and a sealing ring (8). The structure of the pump body (1), the pump cover (2), the impeller (3), the secondary double-suction impeller (4), the bearing support component (5), the sealing component (6), the pump shaft (7) and the sealing ring (8) is the same as that of the prior art and will not be described in detail. It is characterized in that a mixing grid (10) is provided in the transition flow channel (9) in the pump body (1) and the pump cover (2). The mixing grid (10) of the present invention is preferably provided In the middle of the transition flow channel (9), the mixing grid (10) separates the transition flow channel (9) into two flow channel cavities along the direction of the water flow, so that the water flow with the bias flow vortex entering the transition flow channel (9) is blocked by the mixing grid (10) to reduce the flow velocity, significantly reducing the bias flow vortex formed by the suction effect of the impeller (3), reducing the impact and abrasion of the bias flow vortex on the impeller (3), the transition flow channel (9) and the secondary double-suction impeller (4), extending the service life of the impeller (3) and the pump body (1), greatly reducing the maintenance frequency, saving the use cost of the pump, and at the same time, reducing the resonance and noise in the pump body (1), so as to improve the stability of the pump operation.

[0025] As attached Figure 6 、 7 As shown in FIG8 , the present invention can fix adjacent scrapers (11) and particle holding grooves (12) on the outer ring of the water inlet end of the impeller (3) and / or the outer rings at both ends of the secondary double-suction impeller (4), wherein the scrapers (11) and the particle holding grooves (12) are arranged circumferentially, and one end of the particle holding groove (12) extends to the end of the impeller and / or the secondary double-suction impeller to facilitate axial discharge of particles. The outer end of the scraper (11) is exposed from the outer ring of the impeller (3) body and is axially arranged to facilitate the scraper (11) to rotate when in use, and the scraper (11) scrapes off the particles on the sealing ring (8), and the particles fall into the particle holding groove (12) and are washed away by the fluid, thereby avoiding the accumulation or stagnation of particles in the gap between the sealing ring (8) and the impeller (3) during the liquid transportation process, thereby causing the impeller (3) to rotate and stagnate, thereby extending the service life of the sealing ring (8) and significantly improving the working stability.

[0026] As attached Figure 4 、 5 As shown, the present invention can also symmetrically provide two pairs of rectifying grids (13) at the outlet end of the transition flow channel (9), and the rectifying grids (13) are axially arranged to facilitate the rectifying grids (13) to rectify the fluid mixed by the mixing grid (10) again, thereby further reducing the flow resistance of the fluid, so that the stability of the operation is significantly improved.

[0027] As attached Figure 4 、5 As shown, the present invention can also symmetrically provide guide baffles (14) on both sides of the horizontal split position of the transition flow channel (9), and the height and width of the guide baffles (14) gradually decrease in an arc from the outer end toward the pump shaft (7), so as to achieve the purpose of guiding the fluid after the steady flow through the guide baffles (14), thereby improving the operation efficiency and work efficiency of the pump body (1).

[0028] As attached Figure 4 As shown, the present invention can also be provided with an interstage seal (15) between the outlet end of the transition flow channel (9) and the pump shaft (7), the interstage seal (15) is a split structure composed of two half interstage seal bodies (15-1), and the two sides of the two half interstage seal bodies (15-1) are fixedly connected by fixing screws, the outer end of the interstage seal (15) is fixedly connected to the pump body (1) and the pump cover (2) through a positioning pin or a protrusion, and two pairs of rectifying grids (13) are symmetrically provided on one end surface of the interstage seal (15), and the rectifying grids (13) are axially arranged to facilitate the rectification of the fluid mixed by the mixing grid (10) through the rectifying grid (13), thereby reducing the flow resistance of the fluid again, so that the stability of this operation is significantly improved.

[0029] As attached Figure 4 、 5 As shown, the present invention can also symmetrically provide guide baffles (14) on both sides of the horizontal split position of the interstage seal (15), and the height and width of the guide baffles (14) gradually decrease in an arc from the outer end toward the pump shaft (7), so as to achieve the purpose of guiding the fluid after the flow is stabilized through the guide baffles (14), thereby improving the operation efficiency and work efficiency of the pump body (1).

[0030] As attached Figure 3 As shown, the present invention can also provide a labyrinth inner hole (15-1) in the inner hole of the interstage sealing body (15), and the labyrinth inner hole of the interstage sealing body (15) is sealed and connected to the pump shaft (7) through a sealing ring provided therein, so as to improve the sealing performance of the interstage sealing body (15) and the pump shaft (7) through the labyrinth inner hole.

[0031] When the present invention is working, the pump shaft (7) rotates under the drive of the driving motor, driving the impeller (3) and the secondary double-suction impeller (4) to rotate, so that the fluid enters the transition channel (9) in the form of a biased flow vortex under the drive of the rotation of the impeller (3) in the suction chamber. The water flow with the biased flow vortex entering the transition channel (9) is blocked by the mixing grid (10) to reduce the flow velocity, significantly reducing the biased flow vortex formed by the suction effect of the impeller (3), reducing the impact and abrasion of the biased flow vortex on the impeller (3), the transition channel (9) and the secondary double-suction impeller (4), and extending the service life of the impeller (3) and the pump body (1). The maintenance frequency is greatly reduced, saving the use cost of the pump. At the same time, the resonance and noise in the pump body (1) are reduced, so that the stability of the pump operation is improved. When the rectifying grid plate (13) and the guide baffle (14) at the outlet end of the fluid transition flow channel (9) are reduced, the fluid mixed by the mixing grid plate (10) is rectified again by the rectifying grid plate (13), thereby reducing the flow resistance of the fluid again. The fluid with eliminated resistance enters the secondary double-suction impeller (4) under the guidance of the guide baffle (14) and is pumped out. The present invention not only significantly improves the operation stability, but also reduces the noise generated by the fluid resonance.

[0032] During the operation of the present invention, there is a gap between the scraper (11) and the sealing ring (8), that is, the scraper (11) does not contact the sealing ring (8). The number of scrapers (11) is set according to demand, such as 1, 2, 3, or 4. The scraper (11) rotates with the impeller (3). A particle receiving groove (12) is provided on one side of the scraper (11) when it is rotated out. When the impeller (3) rotates, the scraper (11) is driven to scrape off the particles on the front sealing ring (8). The particles fall into the particle receiving groove (12) due to the force of the scraper (11) and are then taken away by the fluid in the pump body (1). Similarly, the outer rings of the left and right ends of the secondary double-suction impeller (4) are also evenly distributed with scrapers (11) and particle receiving grooves (12). The scraper (11) on the double-suction impeller (4) scrapes off the particles on the sealing ring (8) and drops them into the particle holding groove (12) on one side thereof, and is then carried away by the fluid. The present invention has an ingenious structure and can scrape off the particles adhering to the sealing ring (8) during operation. Since the distance between the bottom surface of the particle holding groove and the sealing ring is larger than the gap between the scraper and the sealing ring, the particles are prevented from wearing the sealing ring, making the impeller (3) and the secondary double-suction impeller (4) rotate more smoothly, preventing the rotor from getting stuck, and improving the operational reliability of the pump group. At the same time, it also ensures the sealing performance and the reasonable operating clearance of the moving pump shaft (7) in the pump body (1), thereby reducing the frequency of maintenance and replacement, saving its operating cost, and extending the service life of the pump.

[0033] Due to the adoption of the above structure, the present invention has the advantages of novel structure, high operating efficiency, high working stability, low use cost, low noise, long working life and the like.

Claims

1. A double-inlet multi-stage split-case centrifugal pump, mainly comprising a pump body (1), a pump cover (2), an impeller (3), a secondary double-suction impeller (4), a bearing support component (5), a sealing component (6), a pump shaft (7) and a sealing ring (8), characterized in that A mixing grid (10) is provided in the transition flow channel (9) in the pump body (1) and the pump cover (2), and the mixing grid (10) separates the transition flow channel (9) into two flow channel cavities along the direction of water flow. The outer ring of the water inlet end of the impeller (3) and / or the outer rings at both ends of the secondary double-suction impeller (4) are fixedly provided with adjacent scrapers (11) and particle accommodating grooves (12), and one end of the particle accommodating groove (12) extends to the end of the impeller and / or the secondary double-suction impeller. The scraper (11) and the particle receiving groove (12) are arranged circumferentially, the outer end of the scraper (11) is exposed from the outer ring of the impeller (3), the outlet end of the transition channel (9) is symmetrically provided with two pairs of rectifying gratings (13), the rectifying gratings (13) are axially arranged, and the horizontal split position of the transition channel (9) is symmetrically provided with guide baffles (14) on both sides, and the height and width of the guide baffles (14) gradually decrease in an arc from the outer end to the pump shaft (7). An interstage seal (15) is provided between the outlet end of the transition flow channel (9) and the pump shaft (7). The interstage seal (15) is a split structure consisting of two half interstage seal bodies (15-1), and the two sides of the two half interstage seal bodies (15-1) are fixedly connected by fixing screws. The outer end of the interstage seal (15) is fixedly connected to the pump body (1) and the pump cover (2) via a positioning pin or a protrusion. Two pairs of rectifying grid plates (13) are symmetrically provided on the end surface, and the rectifying grid plates (13) are axially arranged. Flow guide baffles (14) are symmetrically provided on both sides of the horizontally divided position of the interstage sealing body (15). The height and width of the flow guide baffles (14) gradually decrease in an arc from the outer end toward the pump shaft (7). The inner hole of the interstage sealing body (15) is provided with a labyrinth inner hole, and the labyrinth inner hole of the interstage sealing body (15) is sealed and connected to the pump shaft (7).

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