A vertical multistage centrifugal pump with fully open flow passage

Abstract

The invention discloses a vertical multistage centrifugal pump with a fully open flow channel, comprising a motor, an inlet and outlet water housing and a cylinder connected in sequence, a flow channel housing being arranged in the cylinder, the flow channel housing comprising an extrusion section, a middle section and a suction section connected in sequence, a guide impeller being arranged in the flow channel housing, the motor being connected to the cylinder through the inlet and outlet water housing, the inlet and outlet water housing being connected to the extrusion section, the middle section, the suction section and the guide impeller through a pipe; the guide impeller is composed of several stages of impellers connected in sequence from top to bottom, the bottom impeller being located in the suction section, each stage of the impeller comprising a hub and blades covering the hub, the outer edge positions of the inlet and outlet of the blades being connected with a water inlet ring and a water outlet ring; a flange connection surface is arranged at the maximum outer diameter position of the guide impeller, and the connection surface between the extrusion section, the middle section and the suction section is a flange connection stop fitting surface. The invention solves the defects in the traditional vertical multistage centrifugal pump, improves the manufacturing accuracy and hydraulic performance of the centrifugal pump, and is convenient for installation and maintenance.

Description

Technical Field

[0001] The present invention relates to a centrifugal pump, and more particularly to a vertical multi-stage centrifugal pump with a fully open flow passage. Background Art

[0002] The traditional vertical multistage centrifugal pump is also called a cylinder type vertical multistage centrifugal pump. It is designed and manufactured based on the introduction and absorption of foreign advanced technology. It is a mature product that has been widely used in large-scale power station petrochemical projects at home and abroad, with high operating efficiency and reliability. Its structure is as follows Figure 1 and Figure 2 As shown, the water inlet is composed of a trumpet tube 1, a guide vane body 2 and a diffuser 3. Among them, the guide vane body 2 is a casting, and its appearance is a rotating body. From the inside to the outside, it is composed of a hub 4, a blade 5 and a shell 6, thereby forming a closed guide vane body 2 of the centrifugal pump. Since the shell 6 completely encloses the blades 5, the maximum outer circle size is small, which saves materials, but its disadvantages are also obvious. Since the blades 5 are space-distorted curved surfaces and are completely enclosed, it is not easy to check and find, nor is it easy to clean the casting sand and polish, and even sand is trapped inside and cannot be cleaned. The flow path between the blades 5 in the guide vane body 2 is smooth and unobstructed, which has a great influence on the efficiency of the centrifugal pump. Summary of the invention

[0003] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a vertical multi-stage centrifugal pump with a fully open flow channel, which solves the defects in traditional vertical multi-stage centrifugal pumps, improves the manufacturing accuracy and hydraulic performance of the centrifugal pump, and facilitates installation and maintenance.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A vertical multistage centrifugal pump with a fully open flow channel, comprising: a motor, a water inlet and outlet housing and a cylinder connected in sequence from top to bottom, a flow channel housing is arranged in the cylinder, the flow channel housing comprises: an extrusion section, a middle section and a suction section connected in sequence from top to bottom, the suction section is a water inlet, the extrusion section is a water outlet, a guide impeller is arranged in the flow channel housing, the motor is connected to the cylinder through the water inlet and outlet housing, the water inlet and outlet housing is connected to the extrusion section, the middle section, the suction section and the guide impeller through a pipe, and the motor torque is transmitted to the guide impeller through a shaft;

[0006] The impeller is composed of several stages of impellers connected in sequence from top to bottom, the lowest impeller is located in the suction section, each stage of the impeller includes: a hub, and blades covering the hub, and the outer edges of the inlet and outlet of the blades are respectively connected with a water inlet ring and a water outlet ring;

[0007] A plurality of latching teeth are arranged below each stage of the impeller, and a latching groove matching the plurality of latching teeth is arranged in the suction section and the middle section;

[0008] The maximum outer diameter position of the guide impeller is provided with a flange connection surface, the connection surfaces between the discharge section, the middle section and the suction section are flange connection stopper matching surfaces, and the guide impeller is pressed into the flow channel housing through the flange connection surface and bolts;

[0009] The water outlet is connected to the water inlet and outlet housing through a connecting pipe;

[0010] The shaft is provided with a bearing, which is fixed in the cylinder through a bearing bracket;

[0011] An inducer is also arranged in the suction section, and the inducer is fixed on the shaft through an impeller nut.

[0012] The impeller located in the suction section is a first-stage impeller, and the other impellers located in the middle section and the discharge section are secondary impellers.

[0013] Sealing rings are also arranged in the suction section and the middle section.

[0014] The matching surface is also provided with an O-ring.

[0015] A shaft sleeve and a guide bearing are provided between the guide impeller and the shaft, and between the bearing bracket and the shaft.

[0016] The number of the latch teeth and the latch grooves is 1 to 4 pairs.

[0017] In the above technical solution, the vertical multistage centrifugal pump with a fully open flow channel provided by the present invention has re-disassembled and reassembled the flow channel assembly parts of the traditional vertical multistage centrifugal pump, thereby improving the manufacturing accuracy and hydraulic performance of the vertical multistage centrifugal pump and facilitating installation and maintenance. The vertical multistage centrifugal pump of the present invention is simple and easy to design, and has strong operability in terms of manufacturing, installation and maintenance. Due to the improvement in design, the difficulties in manufacturing are solved and the hydraulic efficiency of the centrifugal pump is improved. It has great application value for medium and low specific speed centrifugal pumps with relatively curved and narrow flow channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a flow channel casing in an existing vertical multi-stage centrifugal pump;

[0019] Figure 2 It is a structural schematic diagram of the guide vane body in an existing vertical multi-stage centrifugal pump;

[0020] Figure 3 It is a structural schematic diagram of a vertical multi-stage centrifugal pump of the present invention;

[0021] Figure 4 is a cross-sectional view of a guide impeller in a vertical multi-stage centrifugal pump of the present invention;

[0022] Figure 5It is a schematic structural diagram of the guide impeller in the vertical multi-stage centrifugal pump of the present invention;

[0023] Figure 6 It is a structural schematic diagram of the middle section of the flow channel casing of the vertical multi-stage centrifugal pump of the present invention;

[0024] Figure 7 It is a structural schematic diagram of the flow channel casing suction section of the vertical multi-stage centrifugal pump of the present invention;

[0025] Figure 8 It is a structural schematic diagram of a flow channel casing in a vertical multi-stage centrifugal pump of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Please combine Figures 3 to 8 As shown, a vertical multistage centrifugal pump with a fully open flow channel provided by the present invention comprises: a motor 10, an inlet and outlet water housing 11 and a cylinder 12 connected in sequence from top to bottom, a flow channel housing is arranged in the cylinder 12, the flow channel housing comprises: an extrusion section 13, a middle section 14 and a suction section 15 connected in sequence from top to bottom, the suction section 15 is a water inlet, the extrusion section 13 is a water outlet, a guide impeller 16 is arranged in the flow channel housing, the motor 10 is connected to the cylinder 12 through the inlet and outlet water housing 11, the inlet and outlet water housing 11 is connected to the extrusion section 13, the middle section 14, the suction section 15 and the guide impeller 16 through the connecting pipe 29, the inducer 34 is fixed to the shaft 17 through the impeller nut 18, and the torque of the motor 10 is transmitted to the primary impeller 19, the secondary impeller 20 and the inducer 34 through the shaft 17 to rotate.

[0028] Preferably, the impeller 16 is composed of several levels of impellers connected in sequence from top to bottom, the lowest impeller is located in the suction section, and each level of impeller includes: a hub 21, and blades 22 covering the hub 21, removing the original shell, and the outer edge positions of the inlet and outlet of the blades 22 are respectively connected with a water inlet ring 23 and a water outlet ring 24 to increase the strength of the impeller blades 22 and facilitate manufacturing and installation. The plane and cylindrical surfaces of the water inlet ring 23 and the water outlet ring 24 are precision machined so as to be installed in conjunction with the corresponding parts.

[0029] Preferably, 1-4 pairs of latch teeth 25 are provided below each stage of the impeller, and the suction section 15 and the middle section 14 are provided with latch grooves 26 matched with the plurality of latch teeth 25 to prevent rotation due to the impact of water flow.

[0030] Preferably, a flange connection surface is provided at the maximum outer diameter position of the guide impeller 16, so that the blades 22 of the guide impeller 16 are fully open and the blades 22 are fully exposed. The connection surface between the extrusion section 13, the middle section 14 and the suction section 15 is a flange connection stop mating surface, which is located at the maximum outer diameter of the guide impeller 16 and can move axially relative to each other. It is also equipped with an O-ring 27 to prevent water leakage. The guide impeller 16 is pressed into the flow channel housing through the flange connection surface and bolts 28.

[0031] Preferably, the water outlet of the extrusion section 13 is connected to the water inlet and outlet housing 11 through a pipe 29. A bearing is sleeved on the shaft 17, and the bearing is fixed in the cylinder 12 through a bearing bracket 30. A sealing ring 31 is also provided in the suction section 15 and the middle section 14. A shaft sleeve 32 and a guide bearing 33 are also provided between the guide impeller 16 and the shaft 17. An inducer 34 is also provided in the suction section 15.

[0032] The vertical multi-stage centrifugal pump of the present invention re-disassembles and reassembles the parts of the traditional centrifugal pump. The lower half of the guide vane housing and the trumpet tube are combined into the suction section 15, the upper half of the guide vane housing and the lower half of the adjacent guide vane housing are combined into the middle section 14, and the upper half of the uppermost guide vane housing and the diffuser are combined into the extrusion section 13. After the guide vane housing is removed, a new part guide vane wheel is formed by the hub 21 and the blades 22. The inlet ring 23 and the outlet ring 24 are added to the outer edge of the inlet and outlet edges of the blades 22 to increase the strength of the blades 22 and facilitate manufacturing and installation. The plane and cylindrical surfaces of the inlet ring 23 and the outlet ring 24 are precision machined so as to be installed in conjunction with the corresponding parts.

[0033] The impeller 16 adopts a fully open design method, so that all blades 22 are exposed outside the flow channel housing, which is convenient for processing and grinding to remove sand inclusions. At the same time, the surface of the blade 22 can be turned and milled by a CNC machine tool to ensure that its spatial curved surface shape is completely consistent with the design. The flow channel surface in the suction section 15, the middle section 14 and the extrusion section 13 can also be turned and milled, and the roughness of the flow channel housing surface is further reduced. The fully open split design of the impeller 16 is one of the effective methods to solve the problems of unqualified efficiency and excessive vibration and noise in centrifugal pumps.

[0034] Under the premise of keeping the suction section 15, the middle section 14 and the discharge section 13 unchanged, the performance parameters of the pump can be adjusted by replacing the impeller with different blade 22 inlet angles, and the working range of the pump can be expanded. In addition, it has almost no effect on the efficiency and cavitation of the pump, which is better than adjusting the performance parameters of the pump by cutting the impeller.

[0035] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A vertical multistage centrifugal pump with a fully open flow channel, comprising: The motor, the water inlet and outlet housing and the cylinder are connected in sequence from top to bottom, characterized in that: a flow channel housing is arranged in the cylinder, the flow channel housing comprises: an extrusion section, a middle section and a suction section connected in sequence from top to bottom, the suction section is a water inlet, the extrusion section is a water outlet, a guide impeller is arranged in the flow channel housing, the motor is connected to the cylinder through the water inlet and outlet housing, the water inlet and outlet housing is connected to the extrusion section, the middle section, the suction section and the guide impeller through a pipe, and the motor torque is transmitted to the guide impeller through a shaft; The impeller is composed of several stages of impellers connected in sequence from top to bottom, the lowest impeller is located in the suction section, each stage of the impeller includes: a hub, and blades covering the hub, and the outer edges of the inlet and outlet of the blades are respectively connected with a water inlet ring and a water outlet ring; A plurality of latching teeth are arranged below each stage of the impeller, and a latching groove matching the plurality of latching teeth is arranged in the suction section and the middle section; The maximum outer diameter position of the guide impeller is provided with a flange connection surface, the connection surfaces between the discharge section, the middle section and the suction section are flange connection stopper matching surfaces, and the guide impeller is pressed into the flow channel housing through the flange connection surface and bolts; The water outlet is connected to the water inlet and outlet housing through a connecting pipe; The shaft is provided with a bearing, which is fixed in the cylinder through a bearing bracket; The suction section is also provided with an inducer, which is fixed on the shaft through an impeller nut. The impeller located in the suction section is the primary impeller, and the other impellers located in the middle section and the discharge section are secondary impellers. The suction section and the middle section are also provided with sealing rings. The matching surface is also provided with an O-ring.

2. A vertical multistage centrifugal pump with a fully open flow channel as claimed in claim 1, characterized in that: A shaft sleeve and a guide bearing are provided between the guide impeller and the shaft, and between the bearing bracket and the shaft.

3. A vertical multistage centrifugal pump with a fully open flow channel as claimed in claim 1, characterized in that: The number of the latch teeth and the latch grooves is 1 to 4 pairs.

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