An axial force adjustable centrifugal pump

Abstract

This utility model discloses an axial force adjustable centrifugal pump, relating to the field of self-priming pump technology. It includes a pump body with a suction chamber and a pump cavity interconnected inside. A bearing rod is rotatably mounted within the pump cavity, with an impeller and a balance disc sequentially fixedly fitted at the end of the bearing rod, and a rear pump cover rotatably mounted thereon. The rear pump cover is installed at the rear end of the pump body. This axial force adjustable centrifugal pump features a return water interface on the rear pump cover, connected to the centrifugal pump suction chamber via a return pipe component. The suction chamber is the lowest pressure zone of the centrifugal pump. Pressurized fluid in the mechanical seal cavity flows to the centrifugal pump suction chamber through the return pipe component. The fluid return velocity can be changed by adjusting the gate valve opening of the return pipe component, thereby affecting the pressure difference between the mechanical seal cavity and the pump cavity, thus adjusting the axial force of the centrifugal pump towards the inlet side. This effectively reduces vibration and noise caused by fluid excitation.

Description

Technical Field

[0001] This utility model relates to the field of self-priming pump technology, specifically an axial force adjustable centrifugal pump. Background Technology

[0002] A centrifugal pump is a pump that uses the centrifugal force generated by the rotation of an impeller to transport liquids. It works by utilizing the centrifugal motion of water caused by the rotation of the impeller. Before starting the pump, the pump casing and suction pipe must be filled with water. Then, the motor is started, causing the pump shaft to drive the impeller and water to rotate at high speed. The water undergoes centrifugal motion, being thrown towards the outer edge of the impeller and flowing into the pump's discharge pipe through the flow channel of the volute casing.

[0003] Because the bearing area of ​​the impeller's rear cover plate is larger than that of the front cover plate, most centrifugal pumps, especially high-lift pumps, generate axial force, which points from the drive end towards the impeller inlet. Currently, a rear inlet ring and balance holes on the impeller are generally used to reduce some of the axial force exerted by the fluid on the rotor components (mainly the impeller) towards the inlet side. The principle is that the pressurized fluid entering the mechanical seal cavity through the gap between the impeller's rear inlet ring and the centrifugal pump's rear sealing ring partially flows back to the low-pressure area at the impeller inlet through the balance holes, reducing the pressure within the mechanical seal cavity and thus simultaneously reducing the axial force (pointing towards the inlet side) acting on the impeller's rear cover plate. However, once this structure is finalized, the magnitude of the axial force cannot be changed, and the pressurized fluid flowing back through the balance holes disrupts the flow pattern of the medium at the impeller inlet, generating unnecessary fluid pulsation. This affects the pump's cavitation performance and increases the vibration and noise generated by the pump due to fluid excitation. Utility Model Content

[0004] The purpose of this invention is to provide an axial force adjustable centrifugal pump to solve the problems of vibration and noise caused by fluid excitation in existing centrifugal pumps.

[0005] To achieve the above objectives, this utility model provides the following technical solution: an axial force adjustable centrifugal pump, comprising a pump body, wherein a suction chamber and a pump cavity are provided inside the pump body and are interconnected; a bearing rod is rotatably arranged inside the pump cavity; an impeller and a balance disc are sequentially fixedly sleeved at the end of the bearing rod, and a rear pump cover is rotatably sleeved thereon; the rear pump cover is installed at the rear end of the pump body; a mechanical seal cavity is formed between the balance disc and the rear pump cover; a reflux pipe component is connected to a fixed rod on one side of the pump body; and both ends of the reflux pipe component are respectively connected to the mechanical seal cavity and the suction chamber.

[0006] Preferably, a front pump cover is installed at the front end of the pump body, and the suction chamber is located on one side of the front pump cover.

[0007] Preferably, a rear sealing ring is rotatably sleeved on the outer side of the balance disc, the rear sealing ring is fixed on the inner wall of the rear pump cover, and the side of the balance disc away from the rear pump cover is in contact with the impeller surface wall.

[0008] Preferably, a mechanical seal ring is fixedly sleeved on the outer side of the bearing rod, and the mechanical seal ring is located between the balance disc and the rear pump cover.

[0009] Preferably, a bearing housing component is rotatably sleeved on the outer side of the bearing rod, and the bearing housing component is installed at the rear end of the rear pump cover.

[0010] Preferably, a gate valve is installed on the reflux pipe component.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] This application designs a return water interface on the rear pump cover of the centrifugal pump, which is connected to the centrifugal pump suction chamber through a return pipe component. The suction chamber is the lowest pressure zone of the centrifugal pump. The pressurized fluid in the mechanical seal cavity flows to the centrifugal pump suction chamber through the return pipe component. At this time, the fluid return velocity can be changed by adjusting the opening of the gate valve of the return pipe component, thereby affecting the pressure difference between the mechanical seal cavity and the pump cavity, thereby adjusting the magnitude of the axial force of the centrifugal pump pointing towards the inlet side, thus effectively reducing the vibration and noise caused by fluid excitation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of a conventional centrifugal pump with adjustable axial force according to the present invention;

[0014] Figure 2 This is a schematic diagram of the overall structure of an axial force adjustable centrifugal pump according to the present invention;

[0015] Figure 3 This is a schematic diagram illustrating the axial force analysis within the flow channel of a centrifugal pump with adjustable axial force according to this utility model.

[0016] The following are the labels in the diagram: 1. Suction chamber; 21. Pump body; 22. Pump cavity; 3. Impeller; 4. Rear pump cover; 5. Rear sealing ring; 6. Balance disc; 71. Mechanical seal ring; 72. Mechanical seal cavity; 81. Return pipe assembly; 82. Gate valve; 9. Bearing housing assembly. Detailed Implementation

[0017] 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.

[0018] Example: Figure 1 - Figure 3 As shown, this utility model provides a technical solution for an axial force adjustable centrifugal pump, including a pump body 21. The pump body 21 has a suction chamber 1 and a pump cavity 22 that are interconnected inside. A bearing rod is rotatably arranged inside the pump cavity 22. An impeller 3 and a balance disc 6 are fixedly sleeved at the end of the bearing rod in sequence, and a rear pump cover 4 is rotatably sleeved thereon. The rear pump cover 4 is installed at the rear end of the pump body 21. A mechanical seal cavity 72 is formed between the balance disc 6 and the rear pump cover 4. A fixed rod on one side of the pump body 21 is connected to a return pipe component 81. The two ends of the return pipe component 81 are respectively connected to the mechanical seal cavity 72 and the suction chamber 1.

[0019] Specifically, the pump body 21 is a single-suction, single-stage horizontal structure. This pump body 21 eliminates the rear inlet ring and balance hole structure of the impeller 3. The mechanical seal cavity 72 is separated from the pump cavity 22 by the balance disc 6 and the rear sealing ring 5. The gap between the dynamic and static components allows the high-pressure fluid in the pump cavity 22 to enter the mechanical seal cavity 72. If the fluid entering the mechanical seal cavity 72 does not flow out, the pressure inside the cavity quickly becomes consistent with the high-pressure zone of the pump cavity 22. The axial force F0 of the front cover plate of the impeller 3 points towards the drive end, and the axial force F1 at the outer edge of the rear cover plate points towards the suction end. Since they are both within the pump cavity 22, the pressures are approximately equal, and their axial projected areas are similar. Therefore, F0 and F1 can be approximated as canceling each other out. Similarly, the axial forces in opposite directions between the impeller 3 and the balance disc 6 also cancel each other out. The axial force F2 acting on the balance disc 6 within the mechanical seal cavity 72 becomes the main force acting on the pump rotor's axial force.

[0020] The pump body 21 is generally equipped with a low-noise motor. The bearing of the low-noise motor is fixedly connected to the end of the bearing rod. Since the low-noise motor is an existing technology, its specific form, usage and installation method will not be described in detail in this application.

[0021] The centrifugal pump suction chamber 1 is connected to the suction pipeline through its interface flange. The suction pipeline is a return pipe component 81 located at one end of the suction chamber 1. The interface flange is used to connect other pipelines in the existing technical means. The specific usage, installation method and specific form are all existing technical structures and means, and this application will not elaborate on them.

[0022] like Figure 1 and Figure 2 As shown, a front pump cover is installed at the front end of the pump body 21, and the suction chamber 1 is located on one side of the front pump cover.

[0023] like Figure 1 and Figure 2 As shown, a rear sealing ring 5 is rotatably sleeved on the outer side of the balance disc 6. The rear sealing ring 5 is fixed on the inner wall of the rear pump cover 4. The side of the balance disc 6 away from the rear pump cover 4 is in contact with the surface wall of the impeller 3.

[0024] like Figure 1 and Figure 2 As shown, a mechanical seal ring 71 is fixedly sleeved on the outer side of the bearing rod, and the mechanical seal ring 71 is located between the balance disc 6 and the rear pump cover 4.

[0025] like Figure 1 and Figure 2 As shown, a bearing housing component 9 is rotatably sleeved on the outer side of the bearing rod, and the bearing housing component 9 is installed at the rear end of the rear pump cover 4.

[0026] like Figure 2 As shown, a gate valve 82 is installed on the return pipe component 81;

[0027] Working principle: The centrifugal pump's suction chamber 1 is connected to the suction pipeline via its interface flange. Suction chamber 1 is the lowest pressure zone within the centrifugal pump's flow channel. After the centrifugal pump starts operating, the fluid medium in the suction pipeline is drawn into the impeller 3 through suction chamber 1. The impeller 3 drives the fluid to perform work, increasing its energy. The pump body 21 converts part of the fluid's kinetic energy into pressure energy through the pump chamber 22 and guides it to the outlet, pumping it out to the discharge pipeline. It is evident that the pump chamber 22 is a high-pressure zone. The balance disc 6 and the rear sealing ring 5 isolate the mechanical seal chamber 72 from the pump chamber 22. The gap between the dynamic and static components allows the high-pressure fluid in the pump chamber 22 to enter the mechanical seal chamber 72. If the fluid entering the cavity does not flow, the internal pressure will quickly match the high-pressure zone of the pump cavity 22. If the gate valve 82 is opened at this time, the pressurized fluid in the mechanical seal cavity 72 will flow through the return pipe component 81 to the lowest pressure zone of the centrifugal pump's suction chamber 1. By adjusting the opening of the gate valve 82 of the return pipe component 81, the fluid return velocity can be changed, thereby affecting the pressure difference between the mechanical seal cavity 72 and the pump cavity 22, thus adjusting the magnitude of the axial force of the centrifugal pump pointing towards the inlet side.

[0028] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An axial force adjustable centrifugal pump, comprising a pump body (21), characterized in that: The pump body (21) is provided with a suction chamber (1) and a pump cavity (22) that are interconnected. A bearing rod is rotatably provided in the pump cavity (22). An impeller (3) and a balance disc (6) are fixedly sleeved at the end of the bearing rod in sequence, and a rear pump cover (4) is rotatably sleeved thereon. The rear pump cover (4) is installed at the rear end of the pump body (21). A mechanical seal cavity (72) is formed between the balance disc (6) and the rear pump cover (4). A fixed rod on one side of the pump body (21) is connected to a return pipe component (81). The two ends of the return pipe component (81) are respectively connected to the mechanical seal cavity (72) and the suction chamber (1).

2. The axial force adjustable centrifugal pump according to claim 1, characterized in that: The front end of the pump body (21) is equipped with a front pump cover, and the suction chamber (1) is located on one side of the front pump cover located on the pump body (21).

3. The axial force adjustable centrifugal pump according to claim 1, characterized in that: The outer side of the balance disc (6) is fitted with a rear sealing ring (5), which is fixed to the inner wall of the rear pump cover (4). The side of the balance disc (6) away from the rear pump cover (4) is in contact with the surface wall of the impeller (3).

4. The axial force adjustable centrifugal pump according to claim 3, characterized in that: A mechanical seal ring (71) is fixedly sleeved on the outside of the bearing rod, and the mechanical seal ring (71) is located between the balance disc (6) and the rear pump cover (4).

5. The axial force adjustable centrifugal pump according to claim 1, characterized in that: A bearing housing component (9) is rotatably sleeved on the outside of the bearing rod, and the bearing housing component (9) is installed at the rear end of the rear pump cover (4).

6. The axial force adjustable centrifugal pump according to claim 1, characterized in that: A gate valve (82) is installed on the return pipe component (81).

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