A two-stage horizontal centrifugal pump

Abstract

The utility model discloses a two -stage horizontal centrifugal pump belongs to centrifugal pump technical field. It includes: pump casing, the pump casing is by primary pump shell, secondary pump shell and the communicating pipe sequentially connected and becomes, be equipped with the liquid inlet on the primary pump shell, be equipped with the liquid outlet on the secondary pump shell, the main shaft in the pump cavity, extend along the horizontal direction, are connected with the drive motor through the bearing box, the primary impeller, the baffle and the secondary impeller are sequentially connected on the main shaft, the rotation of the primary impeller with the secondary impeller is opposite, the primary impeller with the primary pump shell forms the primary pump cavity, the secondary impeller with the secondary pump shell forms the secondary pump cavity, after the liquid enters the primary pump cavity through the liquid inlet, under the action of the primary impeller, enters the secondary pump cavity after the communicating pipe, under the action of the secondary impeller, is transported to the liquid outlet. The utility model discloses through two -stage pressure boost to satisfy the demand of high lift while offsetting the axial force, and the material flow resistance is reduced greatly.

Description

Technical Field

[0001] This utility model relates to the field of centrifugal pump technology, and in particular to a two-stage horizontal centrifugal pump. Background Technology

[0002] In coal-water slurry thickening technology, the stable transportation of coal-water slurry is the core link to ensure the continuous operation of the thickening system. At present, the industry mainly relies on two types of pumps to achieve slurry transportation, but both have unavoidable technical defects and cannot meet the requirements of high stability and high efficiency slurry transportation.

[0003] One type uses horizontal screw pumps for slurry conveying. These pumps rely on the cooperation of the rotor and stator to transport materials, but due to the inherent characteristics of coal-water slurry, two key problems exist: First, the slurry often contains large coal particles or foreign objects, which can easily get stuck in the rotor clearance of the screw pump, causing poor rotor operation and directly leading to pump shutdown or fluctuations in output flow. Second, the stator of the screw pump is made of rubber, and large coal particles or foreign objects will continuously rub against the inner wall of the stator during transport, accelerating stator wear and damage. This not only requires frequent stator replacement to maintain operation but also disrupts the operational stability of the thickening system due to frequent equipment start-ups and shutdowns. Another type uses traditional centrifugal pumps for slurry conveying. Traditional centrifugal pumps generate centrifugal force through the high-speed rotation of the impeller, driving the coal-water slurry from the center of the impeller to the surrounding areas and outputting it at high pressure from the outlet. Furthermore, to improve impeller conveying efficiency, the impeller is often designed with a closed structure on both sides. Due to the high concentration and high viscosity of coal-water slurry, it easily adheres to the impeller surface and inner wall of the centrifugal pump during transportation. The adhered coal-water slurry will gradually thicken, which will increase the transportation resistance, leading to a decrease in the pump casing output pressure and a reduction in transportation efficiency. On the other hand, it will disrupt the dynamic balance of the impeller, causing severe vibration of the pump casing, further shortening the service life of the equipment and increasing the system maintenance cost. Utility Model Content

[0004] Therefore, this utility model proposes a two-stage horizontal centrifugal pump that can adapt to the conveying requirements of coal-water slurry.

[0005] To address the aforementioned technical problems, this utility model provides the following technical solution: A two-stage horizontal centrifugal pump includes: a pump housing, which is composed of a primary pump housing, a secondary pump housing, and a connecting pipe connected in sequence; the primary pump housing has an inlet, and the secondary pump housing has an outlet; a main shaft located in the pump chamber, extending horizontally, and connected to a drive motor through a bearing housing; a primary impeller, a baffle plate, and a secondary impeller connected in sequence on the main shaft, the primary impeller and the secondary impeller rotating in opposite directions; the primary impeller and the primary pump housing form a primary pump chamber, and the secondary impeller and the secondary pump housing form a secondary pump chamber; after liquid enters the primary pump chamber through the inlet, it is transported to the connecting pipe under the action of the primary impeller and then enters the secondary pump chamber, and is transported to the outlet under the action of the secondary impeller.

[0006] In some embodiments of this utility model, the liquid inlet extends horizontally and the liquid outlet extends vertically.

[0007] In some embodiments of this utility model, the connecting pipe is connected to the primary pump casing and the connecting pipe is connected to the secondary pump casing via flanges.

[0008] In some embodiments of this utility model, the connecting pipe is connected by flanges through two semi-annular pipe bodies at both ends.

[0009] In some embodiments of this utility model, the primary pump housing and the bearing housing are sealed together by a sealing assembly located between them.

[0010] In some embodiments of this utility model, the sealing assembly includes: a first sealing seat and a second sealing seat, the end faces of the first sealing seat and the second sealing seat abutting each other and connected by a fastening assembly located between them; a sealing area is formed between the inner sidewalls of the first sealing seat and the second sealing seat and the main shaft; a first static sealing ring, a dynamic sealing ring assembly and a second static sealing ring are sequentially disposed in the sealing area.

[0011] In some embodiments of this utility model, the dynamic sealing ring assembly includes a first dynamic sealing ring and a second dynamic sealing ring, and a mounting base located between the two. The mounting base connects the first dynamic sealing ring and the second dynamic sealing ring to the main shaft and rotates therewith.

[0012] In some embodiments of this utility model, the bearing housing is sleeved on the first side of the first sealing seat and connected to the first sealing seat by a fastening assembly located between the two.

[0013] In some embodiments of this utility model, the primary pump housing is sleeved on the second side of the first sealing seat and connected to the end face of the bearing housing by a fastening assembly.

[0014] In some embodiments of this utility model, the main shaft is connected to the output shaft of the drive motor via a coupling assembly, the coupling assembly including a first half coupling, a second half coupling, and a perforated elastic block located between the two; the first half coupling is connected to the main shaft, and the second half coupling is connected to the output shaft of the drive motor.

[0015] The technical solution of this utility model has the following technical advantages over the prior art: The two-stage horizontal centrifugal pump provided by this utility model adopts a series structure of two-stage pump casing and impeller, combined with an impeller design with opposite rotation direction. While achieving efficient two-stage pressurization to meet high head requirements, it also offsets axial force and reduces main shaft load. There is no additional obstruction structure between the impeller and the pump casing, and the flow channel is smooth and continuous, which greatly reduces the material flow resistance and avoids the accumulation and blockage of high-concentration, high-viscosity coal-water slurry. Attached Figure Description

[0016] The preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, which will help to understand the purpose and advantages of this utility model, wherein: Figure 1 A cross-sectional view of a specific embodiment of the two-stage horizontal centrifugal pump provided by this utility model; Figure 2 A top view of a specific embodiment of the two-stage horizontal centrifugal pump provided by this utility model; Figure 3 This is a schematic diagram of the sealing assembly in the two-stage horizontal centrifugal pump provided by this utility model. Detailed Implementation

[0017] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0018] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0020] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1 , Figure 2 The diagram illustrates a specific embodiment of the two-stage horizontal centrifugal pump provided by this invention. The centrifugal pump includes a base 1 and a drive motor 2, a bearing housing 4, and a pump body assembly 5, which are sequentially connected to the base 1. The pump body assembly 5 includes a pump housing formed using a segmented structure. The pump housing is composed of a primary pump housing 51, a secondary pump housing 52, and a connecting pipe 53 connected sequentially. The side wall of the primary pump housing 51 has a radially arranged inlet 511, which serves as the sole inlet for materials and connects to an external supply pipeline. The top of the secondary pump housing 52 has an axially arranged outlet 512, used to transport the pressurized material to subsequent pipelines.

[0022] The primary pump casing 51 and the secondary pump casing 52 form a pump chamber. The main shaft 54, located within the pump chamber, extends horizontally. One end of the main shaft passes through the pump casing and is connected to the drive motor 2 via a bearing housing 4. The bearing housing 4 houses a bearing 41 to ensure the radial and axial stability of the main shaft 54 ​​during high-speed rotation. From near the drive end to far away from the drive end, the main shaft 54 ​​within the pump chamber is sequentially fitted with a primary impeller 55, a partition plate 56, and a secondary impeller 57. All three impellers are interference-fitted to the main shaft 54 ​​via flat keys and locked to the main shaft 54 ​​by lock nuts 58, rotating synchronously with the main shaft 54. The primary impeller 55 and the secondary impeller 57 rotate in opposite directions. This design allows the axial forces generated by the two impellers to cancel each other out during operation, significantly reducing the axial load on the main shaft 54, minimizing bearing wear, and extending the pump's service life. The first-stage impeller 55 and the inner wall of the first-stage pump casing 51 form a first-stage pump chamber, and the second-stage impeller 57 and the inner wall of the second-stage pump casing 52 form a second-stage pump chamber. The two pump chambers are connected by a connecting pipe 53 to achieve material flow. There are no additional guides or obstructions between the impeller and the pump casing. The flow channel cross-section is continuous and smooth, which effectively reduces the material flow resistance and avoids the accumulation of high-viscosity materials in the flow channel.

[0023] The material conveying process is as follows: Materials such as coal-water slurry enter the primary pump chamber through the inlet 511. Under the centrifugal action of the primary impeller 55, they gain initial pressurization and kinetic energy, and are then pushed along the flow channel of the primary pump casing 51 to the connecting pipe 53. After being guided by the connecting pipe 53, the material smoothly enters the secondary pump chamber, where it undergoes secondary pressurization under the further centrifugal action of the secondary impeller 57, and is finally discharged from the outlet 512. Compared with a single-stage centrifugal pump, this two-stage pressurization structure can achieve a higher outlet pressure at the same speed, meeting the requirements for high-lift conveying. Simultaneously, because the flow channel is unobstructed, the material flows smoothly, effectively avoiding clogging problems even for high-concentration coal-water slurry containing particles.

[0024] Specifically, the inlet 511, located on the primary pump casing 51, extends horizontally, with its axis aligned with the axis of the main shaft 54. The inner diameter of the inlet 511 gradually increases from its outer end towards the primary pump chamber, forming a funnel-shaped inlet structure. This horizontal extension design ensures that the flow direction of the material entering the pump chamber is parallel to the plane of rotation of the main shaft 54, reducing impact losses at the material inlet. The funnel-shaped diameter expansion structure reduces the material flow velocity, preventing high-viscosity materials from generating vortices due to sudden velocity changes at the inlet, thus improving feeding stability. The outlet 512 extends vertically, with its axis perpendicular to the axis of the main shaft 54. The inner wall of the outlet 512 has a smooth transition radius. The vertically extending outlet 512 facilitates connection with vertically arranged subsequent conveying pipelines, reducing resistance caused by pipeline turning. The transition radius structure prevents the formation of vortices at the outlet 512, ensuring smooth discharge of pressurized material and further reducing flow losses.

[0025] Specifically, the connecting pipe 53 is connected to the primary pump casing 51 and the secondary pump casing 52 via flanges. Specifically, the outlet end of the primary pump casing 51, the inlet end of the secondary pump casing 52, and both ends of the connecting pipe 53 are equipped with mating flanges, each with multiple bolt holes evenly distributed on it. During connection, a wear-resistant rubber gasket is placed between the flange contact surfaces, and then high-strength bolts are sequentially passed through the bolt holes and tightened. This flange connection method not only facilitates easy disassembly and assembly, making it convenient for later maintenance and replacement of internal pump components, but also effectively ensures the sealing performance of the connection points, preventing high-pressure materials from leaking from the connection.

[0026] The connecting pipe 53 adopts a split structure, consisting of two semi-annular pipes connected by flanges at both ends. One end of each semi-annular pipe is connected to the pump casing flange, and the other end has a matching flange structure. The two semi-annular pipes and the pump casing (including the primary pump casing 51 and the secondary pump casing 52) are connected to form a complete annular flow channel. This split design allows the connecting pipe 53 to be replaced with semi-annular pipes of different inner diameters or flow channel shapes according to different pumping requirements, improving the pump's versatility. At the same time, during installation, the semi-annular pipes can be pre-connected to the primary pump casing 51 and the secondary pump casing 52 respectively before connecting to the intermediate flange, reducing the overall assembly difficulty, and is especially suitable for on-site installation of large pump casings.

[0027] Specifically, in one optional embodiment, the primary pump casing 51 and the bearing housing 4 are sealed together by a sealing assembly 43 located between them. This sealing assembly 43 serves a dual function of connection and sealing, avoiding the structural complexity caused by separately setting up connecting flanges and seals in traditional structures. The sealing assembly 43 prevents high-pressure materials in the primary pump chamber from entering the bearing housing 4, preventing particles in the material from wearing the bearing. It also prevents lubricating oil in the bearing housing 4 from leaking into the pump chamber and contaminating the material, ensuring the reliability of pump operation and the purity of material delivery.

[0028] Specifically, the sealing assembly 43 includes a first sealing seat 431 and a second sealing seat 432. The first sealing seat 431 has a stepped annular structure, and the second sealing seat 432 has an annular flat plate structure. The end faces of both are precision-machined to ensure a good fit. After contact, they are detachably connected by circumferentially evenly distributed fastening components 439. The inner walls of the first sealing seat 431 and the second sealing seat 432 form an annular sealing area with the main shaft 54. Inside this sealing area, a first static sealing ring 433, a dynamic sealing ring assembly, and a second static sealing ring 434 are arranged sequentially. The first static sealing ring 433 and the second static sealing ring 434 are both made of graphite and are fixed to the inner walls of the first sealing seat 431 and the second sealing seat 432 respectively by set screws, keeping them stationary. The dynamic sealing ring assembly is located between the two static sealing rings, and its two end faces are tightly fitted with the end faces of the first static sealing ring 433 and the second static sealing ring 434 respectively, forming two radial sealing surfaces. Compared with the traditional single-end face seal, this multi-seal structure has a significantly improved sealing performance, which can effectively prevent the leakage of high-pressure and high-viscosity materials. At the same time, the static sealing ring made of graphite has good self-lubricating and wear-resistant properties, which extends the service life of the sealing component 43.

[0029] The dynamic sealing ring assembly includes a first dynamic sealing ring 435, a second dynamic sealing ring 436, and a mounting base 437 located between them. Both the first dynamic sealing ring 435 and the second dynamic sealing ring 436 are made of silicon carbide, which has the characteristics of high strength and high wear resistance. The mounting base 437 is an annular sleeve structure. Its inner wall is connected to the main shaft 54 ​​through a keyway, and its outer wall is connected to the first dynamic sealing ring 435 and the second dynamic sealing ring 436 through an interference fit, fixing them coaxially on the main shaft 54 ​​and rotating synchronously with the main shaft 54. The mounting base 437 ensures that the first dynamic sealing ring 435 and the second dynamic sealing ring 436 can maintain synchronous rotation, avoiding wear caused by relative rotation between them. At the same time, the silicon carbide dynamic sealing ring and the graphite static sealing ring form a hard-soft friction pair, which not only has a good sealing effect but also a low coefficient of friction, reducing power loss and improving the pump's operating efficiency.

[0030] Specifically, the bearing housing 4 is sleeved on the first side of the first sealing seat 431 (that is, the side closer to the drive motor 2), and the end face of the bearing housing 4 is in contact with the stepped surface of the first sealing seat 431. The two are connected by circumferentially distributed fastening bolts 438. This connection method makes the bearing housing 4 and the sealing assembly 43 form an integral structure, improving the stability of the main shaft 54 ​​support; at the same time, the stepped surface contact design can axially position the bearing housing 4, preventing axial movement during operation, ensuring the fitting accuracy between the bearing 41 and the main shaft 54, and reducing vibration and noise.

[0031] The primary pump casing 51 is fitted onto the second side (the side away from the drive motor 2) of the first sealing seat 431, and its end face is directly connected to the end face of the bearing housing 4 by fastening bolts. This design indirectly connects the primary pump casing 51 and the sealing assembly 43 through the bearing housing 4, simplifying the overall structure and reducing the number of connecting parts; at the same time, the bearing housing 4, as an intermediate connecting part, has good rigidity and can effectively ensure the coaxiality of the primary pump casing 51 and the main shaft 54, avoiding friction between the impeller and the pump casing due to assembly errors, and improving the smoothness of pump operation.

[0032] Specifically, in one optional embodiment, the main shaft 54 ​​is connected to the output shaft 21 of the drive motor 2 via a coupling assembly 3. The coupling assembly 3 includes a first half-coupling 31, a second half-coupling 32, and a flexible block 33 located between them. The first half-coupling 31 is fixed to the end of the main shaft 54 ​​via a key connection, and the second half-coupling 32 is fixed to the output shaft 21 of the drive motor 2 via a key connection. The opposite end faces of the first half-coupling 31 and the second half-coupling 32 are each provided with toothed grooves adapted to the flexible block 33. The flexible block 33 is made of polyurethane and engages with the two half-couplings respectively through the toothed grooves. Compared with a rigid coupling, this flexible coupling structure can effectively buffer the impact load when the drive motor 2 starts, reducing the additional torque caused by the coaxiality deviation between the main shaft 54 ​​and the motor output shaft 21. The polyurethane flexible block 33 has good elasticity and wear resistance, can absorb vibration during operation, reduce noise, and is easy to replace, improving the maintenance convenience of the equipment.

[0033] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this utility model.

Claims

1. A two-stage horizontal centrifugal pump, characterized in that, include: The pump housing is composed of a primary pump housing, a secondary pump housing, and a connecting pipe connected in sequence. The primary pump housing is provided with an inlet, and the secondary pump housing is provided with an outlet. The main shaft, located inside the pump chamber, extends horizontally and is connected to the drive motor via a bearing housing; A primary impeller, a baffle plate, and a secondary impeller are sequentially connected to the main shaft. The primary impeller and the secondary impeller rotate in opposite directions. A primary pump chamber is formed between the primary impeller and the primary pump casing, and a secondary pump chamber is formed between the secondary impeller and the secondary pump casing. After the liquid enters the primary pump chamber through the inlet, it is transported to the connecting pipe by the action of the primary impeller and then enters the secondary pump chamber by the action of the secondary impeller, and is transported to the outlet by the action of the secondary impeller.

2. A two-stage horizontal centrifugal pump according to claim 1, characterized in that: The inlet extends horizontally, and the outlet extends vertically.

3. A two-stage horizontal centrifugal pump according to claim 2, characterized in that: The connecting pipe is connected to the primary pump casing and the secondary pump casing via flanges.

4. A two-stage horizontal centrifugal pump according to claim 3, characterized in that: The connecting pipe is connected by flanges at both ends of a semi-circular pipe body.

5. A two-stage horizontal centrifugal pump according to claim 1, characterized in that: The primary pump casing and the bearing housing are sealed together by a sealing assembly located between them.

6. A two-stage horizontal centrifugal pump according to claim 5, characterized in that: The sealing assembly includes: A first sealing seat and a second sealing seat, the end faces of the first sealing seat and the second sealing seat abutting each other and connected by a fastening assembly located between them; a sealing area is formed between the inner sidewalls of the first sealing seat and the second sealing seat and the main shaft; The first static sealing ring, the dynamic sealing ring assembly, and the second static sealing ring are sequentially arranged within the sealing area.

7. A two-stage horizontal centrifugal pump according to claim 6, characterized in that: The dynamic sealing ring assembly includes a first dynamic sealing ring and a second dynamic sealing ring, and a mounting base located between them. The mounting base connects the first dynamic sealing ring and the second dynamic sealing ring to the main shaft and rotates therewith.

8. A two-stage horizontal centrifugal pump according to claim 6, characterized in that: The bearing housing is fitted onto the first side of the first sealing seat and is connected to the first sealing seat by a fastening assembly located between the two.

9. A two-stage horizontal centrifugal pump according to claim 6, characterized in that: The primary pump housing is fitted onto the second side of the first sealing seat and is connected to the end face of the bearing housing via a fastening assembly.

10. A two-stage horizontal centrifugal pump according to claim 1, characterized in that: The main shaft is connected to the output shaft of the drive motor via a coupling assembly, which includes a first half coupling, a second half coupling, and a flexible block located between them; the first half coupling is connected to the main shaft, and the second half coupling is connected to the output shaft of the drive motor.

Images