High-suction-height self-priming centrifugal pump

Abstract

The invention provides a high-suction-height self-priming centrifugal pump which comprises a pump body and an impeller, a volute is arranged in the pump body, the impeller is located in the volute, and the impeller is driven by a power device to rotate. A water storage space is arranged at an outlet of the pump body, and an outlet of the volute extends into the water storage space through a drainage channel; a gas-liquid mixing device is arranged between an inlet of the volute and an inlet of the pump body, and air on the inner wall of the inlet is sucked into the gas-liquid mixing device by means of pressure difference formed in the liquid flowing process. The inside of the volute is communicated with the gas-liquid mixing device through a circulating channel and is used for forming backflow jet flow; and carrying out secondary shearing and mixing on the gas-liquid mixed flow by utilizing reflux jet flow. The high-suction-lift self-suction centrifugal pump is simple in overall design and low in manufacturing and maintenance cost, can keep high-suction-lift self-suction capacity under complex working conditions, and effectively overcomes the defects that an existing self-suction centrifugal pump is slow in exhaust, difficult to start and limited in suction lift.

Description

Technical Field

[0001] This invention relates to the field of centrifugal pumps, and particularly to a high-suction-lift self-priming centrifugal pump. Background Technology

[0002] Centrifugal pumps, as one of the most widely used fluid transport devices in industrial and civil fields, rely on the centrifugal force generated by the high-speed rotation of the impeller to lift and transport liquids. Self-priming centrifugal pumps, as an important branch of centrifugal pumps, have the core advantage that after the initial priming, subsequent starts do not require repeated priming. They can automatically remove gas from the suction line and restore normal fluid transport function. Therefore, they play an irreplaceable role in applications requiring frequent start-stop or complex suction conditions, such as agricultural irrigation, municipal drainage, industrial circulation, and emergency fire fighting.

[0003] Despite the significant ease of operation of self-priming centrifugal pumps, their technological development has long faced several bottlenecks. In existing technologies, the most common solution for achieving self-priming is to incorporate a liquid storage chamber or an additional independent gas-liquid separation chamber within the pump body. The liquid storage chamber, by pre-filling the pump body with liquid, forms a gas-liquid mixture during pump startup using impeller agitation. This mixture undergoes initial gas-liquid separation due to density differences, with the gas being discharged and the liquid returning to participate in the next cycle. The gas-liquid separation device reduces the flow velocity by increasing the flow channel volume or changing the flow direction, promoting gas escape from the liquid and being guided to the outlet. However, both of these mainstream technological approaches have inherent limitations. First, their exhaust process largely relies on the fluid's own kinetic energy and gravitational differentiation, resulting in generally low exhaust efficiency and long pump start-up times, making it difficult to meet the demands of rapid response conditions. Second, these structures require a high amount of liquid before initial startup; insufficient liquid storage or incomplete priming can easily lead to self-priming failure and even dry running and wear. Furthermore, the additional liquid storage chamber or separation device not only increases the structural complexity and casting difficulty of the pump body, but also increases material and manufacturing costs, which to some extent limits its popularization and application.

[0004] Furthermore, an improved self-priming centrifugal pump has been disclosed in the prior art. This pump incorporates a suction chamber within the pump body and connects an outlet pipe to a multi-component inlet pipe at the upper and lower ends of the suction chamber, respectively, attempting to optimize the water flow distribution at the suction end. While this design improves the uniformity of suction to some extent compared to conventional structures, its self-priming efficiency, especially during the critical gas removal phase at startup, remains insufficient. The fundamental reason is that this structure fails to achieve proactive and efficient handling of the intake air. Under complex operating conditions such as severe air accumulation in the suction line, a sudden increase in inlet air volume, or the transported medium containing trace impurities affecting the stability of the gas-liquid interface, this technical solution reveals significant shortcomings in the thoroughness and speed of venting. The air is not effectively broken into fine bubbles and fully mixed with the liquid, leading to gas accumulation within the pump and the formation of air resistance. This not only reduces the pump's efficiency and flow rate but may also cause vibration and noise, affecting operational stability and reliability.

[0005] In summary, existing self-priming centrifugal pump technologies generally face a series of interconnected technical challenges, including low venting efficiency, long start-up time, strong dependence on initial filling fluid, high manufacturing costs, and insufficient operational stability under complex operating conditions. The core of these problems lies in the lack of an internal mechanism capable of actively and efficiently handling intake air and achieving rapid and complete venting. Therefore, the industry urgently needs an innovative solution that can fundamentally improve the suction lift, venting efficiency, and start-up speed of self-priming centrifugal pumps while maintaining a simple structure and controllable costs, in order to adapt to more demanding and diverse application environments. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-suction-lift self-priming centrifugal pump. By incorporating a gas-liquid mixing device between the suction inlet and the impeller, the pump actively draws in and breaks up air using the pressure difference created by the liquid flow. Combined with a circulation channel, this achieves multiple gas-liquid mixing and exhaust processes, ensuring timely removal of air from the pump chamber and creating a stable negative pressure zone. This significantly improves the self-priming speed and exhaust efficiency, thereby enhancing the pump's suction lift performance. This invention features a simple overall design, low manufacturing and maintenance costs, and maintains high suction lift self-priming capability under complex operating conditions, effectively overcoming the shortcomings of existing self-priming centrifugal pumps, such as slow exhaust, difficult start-up, and limited suction lift.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0008] A high-suction-lift self-priming centrifugal pump includes a pump body and an impeller. The pump body has a volute, and the impeller is located inside the volute and is driven to rotate by a power device. A water storage space is provided at the outlet of the pump body, and the outlet of the volute extends into the water storage space through a flow channel. A gas-liquid mixing device is provided between the inlet of the volute and the inlet of the pump body. The air inside the inlet is drawn into the gas-liquid mixing device by utilizing the pressure difference formed during the liquid flow. The volute is connected to the gas-liquid mixing device through a circulation channel to form a reflux jet. The reflux jet is used to perform secondary shearing and mixing on the gas-liquid mixture.

[0009] Furthermore, the gas-liquid mixing device includes a first chamber and a second chamber. The inlet of the volute and the inlet of the pump body are divided into the first chamber and the second chamber by a baffle. The second chamber is connected to the inlet of the pump body, and the first chamber is connected to the second chamber through an air intake hole. The baffle is provided with a plurality of mixing holes connected to the second chamber. The pressure difference formed by the liquid flow draws air from the inner wall of the inlet into the first chamber through the air intake hole, and the air is sheared and broken at the mixing hole in the second chamber, mixed with the liquid, and then enters the volute.

[0010] Furthermore, the baffle includes a central sleeve and a cover plate. One end of the central sleeve is connected to the inlet of the volute. The other end of the central sleeve is provided with a cover plate, the edge of which extends to the inner wall of the pump body. The edge of the cover plate is provided with at least one suction hole, and the wall surface of the central sleeve is provided with several mixing holes.

[0011] Furthermore, the mixing hole is an inclined tapering hole, and the centerline of the mixing hole forms an acute angle with the flow direction.

[0012] Furthermore, a spiral acceleration device is provided at the outlet of the circulation channel. The spiral acceleration device includes a tapered spiral guide vane. The outlet of the circulation channel is tapered along the flow direction, and the tapered spiral guide vane is located at the tapered outlet of the circulation channel. The return jet formed at the outlet of the circulation channel is aligned with the second chamber.

[0013] Furthermore, a return channel is provided between the water storage space and the volute, and the outlet of the return channel is staggered with the outlet of the pump body, so that the fluid can return to the volute through the return channel.

[0014] Furthermore, the return channel is a Tesla valve-type one-way channel, used to prevent fluid from entering the water storage space through the return channel.

[0015] Furthermore, the water storage space is provided with a water injection hole, through which water is injected into the volute so that the liquid level at least submerges the impeller, in order to ensure the self-priming effect during startup.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. The high-suction self-priming centrifugal pump of the present invention, by setting a unique gas-liquid mixing device between the inlet of the volute and the inlet of the pump body, and matching it with a circulation channel communicating with the volute, utilizes the local pressure difference formed at the gas-liquid mixing device by the impeller driving the liquid flow during pump operation to actively draw air from the inner wall of the pump body inlet into the first chamber through the suction port. The drawn-in air is then forced through a number of mixing holes (especially inclined tapering holes) set on the baffle in the second chamber. During this process, the high-speed liquid flow violently shears and breaks up the air, forming a fine and uniform gas-liquid mixture, thereby achieving a leapfrog improvement in exhaust efficiency and self-priming speed, and solving the problems of low exhaust efficiency and slow self-priming speed.

[0018] 2. The high-suction self-priming centrifugal pump of the present invention uses a circulation channel to guide the high-pressure fluid in the volute back to the vicinity of the inlet of the gas-liquid mixing device (second chamber), forming a high-speed reflux jet. This reflux jet performs secondary or even multiple shearing and mixing on the gas-liquid flow after the initial mixing, making the bubbles more thoroughly broken down, greatly increasing the gas-liquid contact area, and accelerating the dissolution and entrainment of gas in the liquid.

[0019] 3. The high-suction-lift self-priming centrifugal pump of the present invention, through a combination of active air intake, primary shearing and crushing and secondary mixing enhancement, ensures that the air in the pump chamber can be quickly and thoroughly mixed and discharged with the liquid, thereby forming and maintaining a stable negative pressure zone at the suction inlet, significantly improving exhaust efficiency and self-priming speed, and shortening start-up time.

[0020] 4. The high-suction self-priming centrifugal pump of the present invention has a water storage space at the pump body outlet, and a diversion channel ensures that liquid can enter the space for temporary storage. The water storage space is equipped with a dedicated water injection hole. The design of the water storage space and the convenient water injection hole simplify the pump priming operation and reduce the dependence on the accuracy of the initial liquid filling. Combined with the assistance of the return channel, it ensures that even when there is a lot of gas in the suction pipeline, the pump can quickly establish an effective circulation, achieve rapid start-up, and solve the problems of long start-up time and strong dependence on the initial liquid filling.

[0021] 5. The high-suction self-priming centrifugal pump of the present invention, through a reflux channel (preferably a Tesla valve type one-way channel) set between the water storage space and the volute, can guide part of the liquid back to the volute to participate in circulation during the pump start-up and head building process, further assisting in the initial gas carrying and removal.

[0022] 6. The high-suction self-priming centrifugal pump of the present invention has a gas-liquid mixing device (composed of a central sleeve, cover plate, suction port, mixing port, etc.) directly integrated into the flow channel between the pump body inlet and the volute inlet. The structure is compact and does not require an additional large and complex external gas-liquid separator or special valve group. The circulation channel, return channel, etc. are all realized by using the internal or attached cavity structure of the pump body. The layout is reasonable and avoids too many external pipelines and connectors. This highly integrated design makes the pump body structure relatively simple, with better casting and processing technology, effectively controlling material and manufacturing costs, while improving the reliability of the system.

[0023] 7. The high-suction self-priming centrifugal pump of the present invention, through multiple gas-liquid mixing and shearing mechanisms (initial shearing through mixing holes + secondary mixing through circulating channel return jet), ensures that even when the inlet air volume is large or the medium conditions are unfavorable, it can effectively break up and carry away gas, and can better adapt to complex working conditions such as inlet pressure fluctuations and gas content changes, thus exhibiting better operational stability and reliability.

[0024] 8. The high-suction self-priming centrifugal pump of the present invention has a one-way channel with a Tesla valve structure at the reflux hole, which can effectively prevent the fluid from flowing backward, ensure the one-wayness and circulation stability of the reflux path, thereby maintaining the continuity of the gas-liquid mixing process and the stability of the pump body during high-suction operation. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the high suction lift self-priming centrifugal pump described in this invention.

[0027] Figure 2 This is a schematic diagram of the internal flow direction of the high suction head self-priming centrifugal pump described in this invention.

[0028] Figure 3 This is a schematic diagram of the gas-liquid mixing device described in this invention.

[0029] Figure 4 This is a schematic diagram of the spiral mixing device described in this invention.

[0030] Figure 5 This is a cross-sectional view of the high-suction self-priming centrifugal pump described in this invention along the outlet centerline.

[0031] Figure 6This is a schematic diagram of the flow direction of the high-suction self-priming centrifugal pump along the outlet centerline.

[0032] Figure 7 This is a schematic diagram of the reflux channel of the high suction head self-priming centrifugal pump described in this invention.

[0033] In the picture:

[0034] 1-Pump body; 2-Volume casing; 3-Inlet; 4-Suction hole; 5-Gas-liquid mixing device; 5-1-Baffle; 5-1-1-Central sleeve; 5-1-2-Cover plate; 5-2-First chamber; 5-3-Second chamber; 5-4-Mixing hole; 6-Drainage channel; 7-Water storage space; 8-Spiral acceleration device; 9-Circulation channel; 10-Impeller; 11-Sealing assembly; 12-Motor; 13-Return channel; 14-Sealing cover; 15-Outlet; 16-Water injection hole. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 mechanical connection or an electrical 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 invention according to the specific circumstances.

[0038] like Figure 1 and Figure 2 As shown, the high-suction self-priming centrifugal pump of the present invention includes a pump body 1 and an impeller 10. The pump body 1 has a volute 2 inside, and the impeller 10 is located inside the volute 2. The impeller 10 is driven to rotate by a power device. Generally, a motor 12 is connected to a rotating shaft through a coupling. The rotating shaft is connected to the impeller 10. A sealing assembly 11 is provided between the rotating shaft and the pump body 1 for sealing. Generally, the sealing assembly 11 is a mechanical seal. A water storage space 7 is provided at the outlet 15 of the pump body 1. The outlet of the volute 2 extends into the water storage space 7 through a flow channel 6. A gas-liquid mixing device 5 is provided between the inlet of the volute 2 and the inlet of the pump body 1. The air inside the inlet 3 is drawn into the gas-liquid mixing device 5 by utilizing the pressure difference formed during the liquid flow. The volute 2 is connected to the gas-liquid mixing device 5 through a circulation channel 9 to form a reflux jet. The reflux jet is used to perform secondary shearing and mixing on the gas-liquid mixture. This invention uses a combination of active air intake, primary shearing and crushing, and secondary mixing enhancement to ensure that the air in the pump chamber is quickly and thoroughly mixed and discharged with the liquid, thereby forming and maintaining a stable negative pressure zone at the inlet, significantly improving exhaust efficiency and self-priming speed, and shortening start-up time.

[0039] like Figure 3 As shown, the gas-liquid mixing device 5 includes a first chamber 5-2 and a second chamber 5-3. The inlet of the volute 2 and the inlet of the pump body 1 are divided into the first chamber 5-2 and the second chamber 5-3 by a baffle 5-1. The second chamber 5-3 is connected to the inlet 3 of the pump body 1, and the first chamber 5-2 is connected to the second chamber 5-3 through a suction hole 4. The baffle 5-1 is provided with a plurality of mixing holes 5-4 that are connected to the second chamber 5-3. The air inside the inlet 3 is drawn into the first chamber 5-2 through the suction hole 4 by the pressure difference formed by the liquid flow, and the air is sheared and broken at the mixing hole 5-4 of the second chamber 5-3, mixed with the liquid and then enters the volute 2. This invention utilizes a motor 12 to drive an impeller 10 to rotate, causing the liquid flow to create a local pressure difference at the gas-liquid mixing device 5. This pressure difference actively draws air from the inner wall of the pump inlet 3 into the first chamber 5-2 through the suction port 4. The drawn-in air is then forced through several mixing holes 5-4 on the baffle 5-1 in the second chamber 5-3. During this process, the high-speed liquid flow violently shears and breaks up the air, forming a fine and uniform gas-liquid mixture, thereby achieving a leapfrog improvement in exhaust efficiency and self-priming speed.

[0040] like Figure 3As shown, the baffle 5-1 includes a central sleeve 5-1-1 and a cover plate 5-1-2. One end of the central sleeve 5-1-1 is connected to the inlet of the volute 2; the other end of the central sleeve 5-1-1 is provided with a cover plate 5-1-2, the edge of which extends to the inner wall of the pump body 1; the edge of the cover plate 5-1-2 is provided with at least one suction hole 4, and the wall surface of the central sleeve 5-1-1 is provided with several mixing holes 5-4. The mixing holes 5-4 are inclined tapering holes, and the centerline of the mixing holes 5-4 forms an acute angle θ with the flow direction, typically 30~60°. The central sleeve and cover plate of this invention can be directly integrated into the flow channel between the pump body inlet and the volute inlet, resulting in a compact structure that eliminates the need for a large and complex external gas-liquid separator or special valve assembly. In some embodiments, the central sleeve 5-1-1 is a sleeve that gradually narrows along the flow direction, and the cover plate 5-1-2 is inclined, so that the first chamber 5-2 formed with the pump body 1 is a chamber that gradually narrows along the flow direction.

[0041] like Figure 4 As shown, a spiral acceleration device 8 is provided at the outlet of the circulation channel 9. The spiral acceleration device 8 includes a tapering spiral guide vane. The outlet of the circulation channel 9 is tapering along the flow direction, and the tapering spiral guide vane is located at the tapering outlet of the circulation channel 9. The return jet formed at the outlet of the circulation channel 9 is aligned with the second chamber 5-3. The circulation channel 9 guides the high-pressure fluid in the volute 2 back to the vicinity of the inlet of the second chamber 5-3, forming a high-speed return jet. The spiral acceleration device 8 can form a high-speed rotating jet. The high-speed rotating return jet performs secondary or even multiple shearing and mixing on the gas-liquid flow after the initial mixing, making the bubbles more thoroughly broken up, greatly increasing the gas-liquid contact area, and accelerating the dissolution and entrainment of gas in the liquid. In the embodiments, the optimal flow velocity of the return jet output by the spiral accelerator 8 is generally between 15 m / s and 35 m / s. If the flow velocity is too low (<10 m / s), the kinetic energy of the jet is insufficient, and it cannot effectively form a secondary shear on the gas-liquid flow after the initial mixing, making it difficult to further tear the already initially broken bubbles into finer and more stable bubbles. This will lead to insufficient gas-liquid mixing and reduced exhaust efficiency. Although excessively high flow velocities (>40 m / s) have a stronger shearing effect, they will cause a sharp increase in the flow resistance (head loss) of the circulation channel and the jet device itself. This energy loss needs to be provided by the impeller, which will reduce the overall efficiency of the pump, resulting in a net loss. In local low-pressure areas, excessively high flow velocities will significantly increase the risk of cavitation. Cavitation will not only damage the pump's flow-through components (such as the spiral accelerator, impeller, etc.), generating noise and vibration, but will also disrupt the stability of the flow field, thus negatively impacting the gas-liquid mixing process.

[0042] like Figure 5 , Figure 6 and Figure 7As shown, a water storage space 7 is provided at the outlet 15 of the pump body 1, and the outlet of the volute 2 extends into the water storage space 7 through a flow channel 6. A return channel 13 is provided between the water storage space 7 and the volute 2, and the outlets of the flow channel 6 and the pump body 1 outlet 15 are staggered to allow fluid to return to the volute 2 through the return channel 13. The return channel 13 is a Tesla valve type one-way channel to prevent fluid from entering the water storage space 7 through the return channel 13. A water injection hole 16 is provided on the water storage space 7, through which water is injected into the volute 2 so that the liquid level at least submerges the impeller 10 to ensure the self-priming effect during startup. This invention features a water storage space 7 at the pump outlet 15, with a flow channel 6 ensuring liquid can temporarily enter and be stored within it. The water storage space 7 has a dedicated water injection hole. This design, along with the convenient water injection hole 16, simplifies pump priming operations and reduces reliance on the accuracy of initial priming. Combined with the assistance of the return channel 13, this ensures that even with a large amount of gas in the suction line, the pump can quickly establish effective circulation, enabling rapid start-up and solving the problems of long start-up times and high dependence on initial priming. The water injection hole 16 is equipped with a sealing cap 14 to prevent dust or debris from entering when not in use.

[0043] like Figure 7 As shown in the embodiment, the return channel 13 is threadedly sealed on the pump body 1 in the form of a plug, and is installed between the water storage space 7 and the volute 2. The plug is equipped with a Tesla valve, which facilitates cleaning of the Tesla valve in the return channel 13.

[0044] The working principle is as follows:

[0045] Fluid enters the gas-liquid mixing channel 5 through pump inlet 3 and flows at high speed. Geometric contraction and velocity increase within the channel create localized low pressure before and after the mixing orifice 5-4. This pressure difference causes the suction holes 4 on the channel wall to actively draw air from the inner wall of inlet 3 into the channel. The drawn-in air, within the first chamber 5-2, comes into contact with the high-speed liquid flow at the mixing orifice 5-4 through a narrow channel. It is sheared and impacted, breaking into tiny bubbles that form a gas-liquid mixture. The central sleeve 5-1-1 guides this mixture accurately into the inlet position of impeller 10. The returning liquid enters the spiral mixing device 8 located at the circulation end through circulation channel 9. The high-speed liquid flow violently shears and breaks up the bubbles, forming a fine, uniform gas-liquid mixture. This mixture then re-enters the impeller through gas-liquid mixing device 5, forming multiple cycles of mixing until the gas in the pump chamber is fully exhausted. A Tesla valve-type one-way channel is installed in the return channel 13 to ensure that the return process is unidirectional, thus preventing reverse flow during the circulation phase from affecting exhaust efficiency. When the water storage space 7 is full, the pump enters the normal pressurization and delivery state, and the liquid is stably delivered through the outlet 15.

[0046] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0047] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-suction-lift self-priming centrifugal pump, comprising a pump body (1) and an impeller (10), wherein the pump body (1) has a volute (2) inside, and the impeller (10) is located inside the volute (2), and the impeller (10) is driven to rotate by a power device; characterized in that, The pump body (1) has a water storage space (7) at its outlet, and the outlet of the volute (2) extends into the water storage space (7) through the diversion channel (6). A gas-liquid mixing device (5) is provided between the inlet of the volute (2) and the inlet of the pump body (1). The air inside the inlet is drawn into the gas-liquid mixing device (5) by utilizing the pressure difference formed during the liquid flow. The volute (2) is connected to the gas-liquid mixing device (5) through the circulation channel (9) to form a reflux jet. The reflux jet is used to perform secondary shearing and mixing of the gas-liquid mixture.

2. The high-suction-lift self-priming centrifugal pump according to claim 1, characterized in that, The gas-liquid mixing device (5) includes a first chamber (5-2) and a second chamber (5-3). The inlet of the volute (2) and the inlet of the pump body (1) are divided into the first chamber (5-2) and the second chamber (5-3) by a baffle (5-1). The second chamber (5-3) is connected to the inlet of the pump body (1). The first chamber (5-2) is connected to the second chamber (5-3) through the suction hole (4). The baffle (5-1) is provided with a plurality of mixing holes (5-4) connected to the second chamber (5-3). The air inside the inlet (3) is drawn into the first chamber (5-2) through the suction hole (4) by the pressure difference formed by the liquid flow. The air is sheared and broken at the mixing hole (5-4) of the second chamber (5-3) and mixed with the liquid before entering the volute (2).

3. The high-suction-lift self-priming centrifugal pump according to claim 2, characterized in that, The baffle (5-1) includes a central sleeve (5-1-1) and a cover plate (5-1-2). One end of the central sleeve (5-1-1) is connected to the inlet of the volute (2). The other end of the central sleeve (5-1-1) is provided with a cover plate (5-1-2). The edge of the cover plate (5-1-2) extends to the inner wall of the pump body (1). The edge of the cover plate (5-1-2) is provided with at least one suction hole (4). The wall surface of the central sleeve (5-1-1) is provided with several mixing holes (5-4).

4. The high-suction-lift self-priming centrifugal pump according to claim 3, characterized in that, The mixing hole (5-4) is an inclined tapering hole, and the center line of the mixing hole (5-4) forms an acute angle with the flow direction.

5. The high-suction-lift self-priming centrifugal pump according to claim 2, characterized in that, The circulation channel (9) is provided with a spiral acceleration device (8) at the outlet. The spiral acceleration device (8) includes a tapered spiral guide vane. The outlet of the circulation channel (9) is tapered along the flow direction. The tapered spiral guide vane is located at the tapered outlet of the circulation channel (9). The backflow jet formed at the outlet of the circulation channel (9) is aligned with the second chamber (5-3).

6. The high-suction-lift self-priming centrifugal pump according to claim 1, characterized in that, A return channel (13) is provided between the water storage space (7) and the volute (2). The outlet of the diversion channel (6) and the outlet (15) of the pump body (1) are staggered, so that the fluid can return to the volute (2) through the return channel (13).

7. The high-suction-lift self-priming centrifugal pump according to claim 6, characterized in that, The return channel (13) is a Tesla valve type one-way channel, used to prevent fluid from entering the water storage space (7) through the return channel (13).

8. The high-suction-lift self-priming centrifugal pump according to claim 1, characterized in that, The water storage space (7) is provided with a water injection hole (16). Water is injected into the volute (2) through the water injection hole (16) so that the liquid level is at least submerged in the impeller (10) to ensure the self-priming effect during startup.

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