Liquid delivery pump

Abstract

The invention provides a liquid delivery pump which comprises a first shell, a second shell and a liquid delivery pump body. The second shell comprises a pump inlet, a pump outlet and a pump cavity which is in fluid communication with the pump inlet and the pump outlet; the impeller assembly comprises a centrifugal impeller and an axial flow impeller, and at least part of the impeller assembly is arranged in the pump cavity of the second shell; the impeller assembly comprises a hollow body part, the hollow body part comprises a first end adjacent to the pump inlet and a second end which is far away from the pump inlet and is opposite to the first end, the axial flow impeller is formed at the first end of the hollow body part, and the centrifugal impeller is formed at the second end of the hollow body part; and the driving assembly is at least partially arranged in the containing cavity of the first shell, and the driving assembly is configured to drive the impeller assembly to operate. The axial flow pump is additionally arranged at the front end of the centrifugal pump, the air binding problem of the centrifugal pump is solved, and the reliability of the liquid conveying pump is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water pumps and the field of fluid machinery, and in particular to a liquid delivery pump. Background Art

[0002] A liquid delivery pump is a device that converts mechanical energy into liquid kinetic energy. It is widely used in fields such as farmland irrigation, industrial production, urban water supply and sewage treatment. Among various types of liquid delivery pumps, vertical submersible centrifugal pumps are widely used in various industrial fields due to their advantages such as high efficiency, energy saving and small footprint. However, centrifugal pumps often encounter air binding problems during use, that is, the pump cavity is filled with air. Due to the low air density, the centrifugal force generated by the pump after starting rotation is small, and the low pressure formed in the center of the impeller is not enough to suck the liquid into the pump cavity, so the liquid delivery pump cannot pump the liquid normally.

[0003] The existing technology mainly dispels the air by setting a water pipe in the pump cavity and using the water pipe to introduce liquid into the pump cavity. In addition, there are some technical solutions that dispel the air by setting a nozzle in the pump cavity and using the nozzle to spray liquid, thereby forming a negative pressure and discharging the air from the pump cavity. Although these methods can solve the air binding problem to a certain extent, they require additional water pipes or nozzles, which increases the complexity and cost of the equipment. Moreover, these methods can only temporarily solve the air binding problem. If air enters the pump cavity again, the water pump still cannot work normally.

[0004] Therefore, there is an urgent need for a method and device that can solve the air binding of a centrifugal pump without adding an additional water diversion pipe or nozzle. Summary of the invention

[0005] In order to solve the above problems and defects in the prior art, the purpose of the present invention is to provide a method and device that can solve the air binding of a centrifugal pump without adding an additional water diversion pipe or nozzle.

[0006] Based on this, according to one embodiment of the present invention, there is provided a liquid delivery pump, comprising: a first shell defining a accommodating chamber; a second shell comprising a pump inlet, a pump outlet and a pump chamber in which a fluid is connected to the pump inlet and the pump outlet; an impeller assembly comprising a centrifugal impeller and an axial flow impeller, which is at least partially disposed in the pump chamber of the second shell; the impeller assembly comprises a hollow body, the hollow body comprising a first end adjacent to the pump inlet and a second end opposite to the first end away from the pump inlet, the axial flow impeller is formed at the first end of the hollow body, and the centrifugal impeller is formed at the second end of the hollow body; a drive assembly, which is at least partially disposed in the accommodating chamber of the first shell, and the drive assembly is configured to drive the impeller assembly to operate.

[0007] In one embodiment, the drive assembly is configured to drive the axial flow impeller to rotate to draw liquid from the pump inlet into the pump chamber, and drive the centrifugal impeller to rotate to transport the liquid drawn by the axial flow impeller to the pump outlet via the pump chamber.

[0008] In one embodiment, the impeller assembly is integrally formed, and the axial flow impeller and the centrifugal impeller rotate coaxially.

[0009] In one embodiment, the second end of the hollow body includes a disc-shaped portion extending radially outward, the centrifugal impeller includes a plurality of centrifugal blades arranged circumferentially at intervals on the disc-shaped portion, and the axial flow impeller includes a plurality of axial flow blades arranged circumferentially at intervals on the inner wall of the first end.

[0010] In one embodiment, the drive assembly includes a brushless DC motor.

[0011] In one embodiment, the accommodating cavity of the first shell includes a first sub-cavity and a second sub-cavity, the stator of the brushless DC motor is disposed in the first sub-cavity, and the rotor of the brushless DC motor is disposed in the second sub-cavity and coupled to the impeller assembly.

[0012] In one embodiment, the second housing includes an outward protrusion adjacent to the axial flow impeller, and a through hole is formed on a side of the outward protrusion to define the pump inlet.

[0013] In one embodiment, a top of the outward protrusion is formed with a column inserted into the hollow body from the first end.

[0014] According to another exemplary embodiment of the present invention, a liquid delivery pump is provided, comprising: a first shell defining a accommodating chamber; a second shell comprising a pump inlet, a pump outlet and a pump chamber fluidly connected to the pump inlet and the pump outlet, wherein the pump inlet is formed by a mouth extending outward from the second shell, and the mouth is formed with circumferentially distributed grooves; an impeller assembly at least partially disposed in the pump chamber of the second shell, the impeller assembly comprising a centrifugal impeller and an axial flow impeller coaxially connected in series with the centrifugal impeller, the axial flow impeller being arranged adjacent to the mouth of the second shell; a drive assembly at least partially disposed in the accommodating chamber of the first shell, the drive assembly being configured to drive the impeller assembly to operate.

[0015] In another embodiment, the drive assembly is configured to drive the axial flow impeller to rotate to draw liquid from the pump inlet into the pump chamber, and drive the centrifugal impeller to rotate to transport the liquid drawn by the axial flow impeller to the pump outlet via the pump chamber.

[0016] In another embodiment, the driving assembly includes a driving shaft, and the centrifugal impeller and the axial flow impeller are sleeved on the driving shaft.

[0017] In another embodiment, the drive assembly includes a brushless DC motor.

[0018] In the aforementioned exemplary embodiments of the present invention, compared with the prior art, the present invention can solve the air binding problem without adding additional water pipes or nozzles, and also improves the practicality and economy of the liquid delivery pump. By adding an axial flow pump to the front end of the centrifugal pump, the air inside the pump chamber and the impeller is forced out before the liquid delivery pump is started, avoiding the air binding of the centrifugal pump not only improves the reliability and stability of the liquid delivery pump, but also extends the service life of the liquid delivery pump and reduces maintenance costs. Secondly, the technical solution uses the same speed to drive the centrifugal pump and the axial flow pump, which simplifies the design of the equipment and reduces the complexity and cost of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The features, advantages and other aspects of the embodiments of the present invention will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings, in which several embodiments of the present invention are shown in an exemplary and non-limiting manner. In the accompanying drawings:

[0020] Figure 1 A cross-sectional view of a liquid delivery pump according to an embodiment of the present invention;

[0021] Figure 2 A bottom schematic diagram of a liquid delivery pump according to an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of an integrated rotor and impeller according to an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a centrifugal impeller according to an embodiment of the present invention;

[0024] Figure 5 A schematic diagram showing an integrated rotor and impeller according to another embodiment of the present invention from another perspective;

[0025] Figure 6 A schematic diagram of a bottom view of an integrated rotor and impeller according to an embodiment of the present invention;

[0026] Figure 7 It is an exploded schematic diagram of a liquid delivery pump according to an embodiment of the present invention;

[0027] Figure 8 A cross-sectional view of a liquid delivery pump according to another embodiment of the present invention;

[0028] Fig. 9A bottom schematic diagram of a liquid delivery pump according to another embodiment of the present invention;

[0029] Fig.10 The figure is an exploded schematic diagram of a liquid delivery pump according to another embodiment of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0031] The terms "including", "comprising" and similar terms used herein should be understood as open terms, i.e., "including / including but not limited to", indicating that other contents may also be included. The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment", and so on.

[0032] The existing technology mainly solves the air binding problem of centrifugal pumps by setting a water pipe or nozzle in the pump cavity to discharge the air from the pump cavity and make the centrifugal pump work normally. However, if air enters the pump cavity again, the water pump still cannot work normally. Therefore, the existing technology not only increases the complexity and cost of the liquid delivery pump, but also has great limitations.

[0033] The liquid delivery pump according to each embodiment of the present invention can be provided with an axial flow at the front end of the centrifugal pump. The self-priming ability of the axial flow pump can generate negative pressure, thereby discharging the air in the entire pump cavity, effectively solving the air binding problem. The liquid delivery pump of each embodiment of the present invention will be described below in conjunction with the accompanying drawings.

[0034] Figure 1 A cross-sectional view of a liquid delivery pump according to an embodiment of the present invention is shown; Figure 2 FIG. 2 shows a bottom schematic diagram of a liquid delivery pump according to an embodiment of the present invention. Figure 1 and Figure 2 The exemplary liquid delivery pump 10 includes a first housing 11, a second housing 12, an impeller assembly 13, and a drive assembly 16. The second housing 12 includes a pump inlet 121, a pump outlet 122, and a pump cavity 123 that fluidly connects the pump inlet 121 and the pump outlet 122.

[0035] The impeller assembly 13 is at least partially disposed in the pump cavity 123 of the second housing 12. The impeller assembly 13 includes a centrifugal impeller 14 and an axial flow impeller 15. The axial flow impeller 15 may be disposed adjacent to the pump inlet 121 of the second housing 12.

[0036] The structure of the impeller assembly 13 can take many forms. In one embodiment, the impeller assembly 13 may include a hollow body 131. The hollow body 131 may include a first end 132a adjacent to the pump inlet 121 and a second end 132b opposite to the first end 132a away from the pump inlet 121. The axial impeller 15 may be formed at the first end 132a of the hollow body 131, and the centrifugal impeller 14 may be formed at the second end 132b of the hollow body 131. In one embodiment, the second end 132b of the hollow body 131 may be arranged adjacent to the pump outlet 122.

[0037] The driving assembly 16 is at least partially disposed in the accommodating chamber 111 of the first housing 11 to drive the impeller assembly 13 to operate. In one embodiment, the driving assembly 16 can drive the axial flow impeller 15 to rotate so as to suck the liquid from the pump inlet 121 into the pump chamber 123, and drive the centrifugal impeller 14 to rotate so as to deliver the liquid sucked by the axial flow impeller 15 to the pump outlet 122 via the pump chamber 123. When the driving assembly 16 drives the axial flow impeller 15 to rotate, the axial flow impeller 15 will suck the liquid from the outside of the liquid delivery pump 10 into the pump inlet 121 through the axial force generated by its rotation. Since the axial flow impeller 15 generates self-priming force when rotating, a negative pressure can be formed at the pump inlet 121, which helps the liquid to quickly fill the pump chamber 123, so that the air originally existing in the pump chamber 123 is pushed to the pump outlet 122 by the liquid flow and discharged, ensuring that no air is retained in the pump chamber 123. At the same time, the driving assembly 16 drives the centrifugal pump 14 to rotate. Under the rotation of the axial flow impeller 15 , the air in the pump chamber 123 is eliminated and filled with liquid. The centrifugal force generated by the rotation of the centrifugal impeller 14 further pressurizes the liquid in the pump chamber 123 and pushes the liquid to the pump outlet 122 , and finally the liquid is discharged from the pump outlet 122 .

[0038] In one embodiment, the axial flow impeller 15 and the centrifugal impeller 14 can be arranged to rotate coaxially. Coaxial rotation can ensure that the centrifugal impeller 14 and the axial flow impeller 15 have the same rotation speed, simplifying the equipment design while reducing the complexity and cost of the equipment.

[0039] In one embodiment, the impeller assembly 13 may be integrally formed. However, in other embodiments, the axial flow impeller 15 and the centrifugal impeller 14 in the impeller assembly 13 may also be two separate components.

[0040] In one embodiment, the second housing 12 further includes an outward protrusion 124 adjacent to the axial flow impeller 15. The side of the outward protrusion 124 may be formed with a plurality of evenly distributed through holes 125 (e.g., four through holes), which define the pump inlet 121. It is understood that the number of through holes 125 is not limited to four, and it can be set according to actual needs. A column 126 is also formed on the top of the outward protrusion 124, which is inserted into the hollow body 131 from the first end 132a, so that the liquid entering the pump chamber 123 through the through hole 125 flows axially upward along the column 126.

[0041] In one embodiment, the drive assembly 16 may be a brushless DC motor. A brushless DC motor generally has no carbon brushes, which can reduce wear, thereby improving motor efficiency and reliability, and also has the advantage of low noise. However, in other embodiments, the drive assembly 16 may also be other types of motors or structures with a driving function.

[0042] In one embodiment, the accommodating chamber 111 defined by the first housing 11 may further include a first sub-chamber 111a and a second sub-chamber 111b. The stator 161 of the brushless DC motor may be disposed in the first sub-chamber 111a. The rotor 162 of the brushless DC motor may be disposed in the second sub-chamber 111b and coupled to the impeller assembly 13 to drive the centrifugal impeller 14 and the axial flow impeller 15 in the impeller assembly 13 to rotate.

[0043] The stator 161 can be made of, for example, laminated silicon steel sheets with coils wound on them. The current connected by the motor driver (not shown) starts the drive assembly 16 and causes the stator 161 to generate a rotating magnetic field. The rotor 162 can be made of, for example, a magnetic ring magnet covered with an annular plastic, or other materials with good conductivity such as copper or aluminum. The rotor 162 is cut by the magnetic lines of force in the rotating magnetic field generated by the stator 161, thereby generating current. These currents interact with the magnetic field generated by the stator 161 to form an electromagnetic torque, driving the rotor 162 to rotate continuously.

[0044] Figure 3 A schematic diagram showing an integrated rotor and impeller according to an embodiment of the present invention is shown; Figure 4 FIG. 2 shows a schematic diagram of a centrifugal impeller according to an embodiment of the present invention. Figure 3 and Figure 4, the centrifugal impeller 14 is coupled with the rotor 162, and forms an integrated structure of the rotor 162 and the impeller assembly 13. In one embodiment, the second end 132b of the hollow body 131 of the impeller assembly 13 may also include a disc-shaped portion 133 extending radially outward. The centrifugal impeller 14 may include a plurality of centrifugal blades 141, which are arranged axially spaced on the disc-shaped portion 133. The number of centrifugal blades 141 may be two or more, and they are centrally symmetrically arranged on the disc-shaped portion 133. The inner wall of the hollow portion 1621 of the rotor 162 may also include a bearing 18, which is used to support the rotation of the rotor 162, and can effectively reduce the friction generated during the rotation of the rotor 162, ensure its rotation accuracy, and reduce its maintenance cost in subsequent use. The bearing 18 may be made of graphite material, for example, or may be made of other materials with good self-lubrication, chemical stability and high temperature resistance.

[0045] Figure 5 Another perspective schematic diagram of an integrated rotor and impeller according to an embodiment of the present invention is shown; Figure 6 FIG. 1 is a schematic diagram showing a bottom view of an integrated rotor impeller according to an embodiment of the present invention. Figure 5 and Figure 6 The axial flow impeller 15 includes a plurality of axial flow blades 151, which are arranged axially at intervals on the inner wall of the first end 132a of the hollow body 131. The number of the axial flow blades 151 can be two or more, which can be set according to actual needs. For example, when the head of the axial flow pump formed by the axial flow impeller 15 is not higher than two meters, the number of the axial flow blades 151 can be two to four; when the head is higher than two meters, the number of the axial flow blades 151 can be five to ten.

[0046] The centrifugal pump formed by the centrifugal impeller 14 usually has a low flow and high head characteristic, while the axial flow pump formed by the axial flow impeller 15 usually has a high flow and low head characteristic. Therefore, when the centrifugal impeller 14 rotates coaxially with the axial flow impeller 15, if the ratio of the height H of the axial flow blade 151 to the diameter D of the axial flow impeller 15 is improperly set, it will have a negative impact on the performance of the centrifugal pump. Possible negative impacts include, for example, lower head of the centrifugal pump, smaller flow, higher noise, and higher power of the entire liquid delivery pump system. Therefore, according to the analysis of experimental data, when the ratio of the height H of the axial flow blade 151 to the diameter D of the axial flow impeller 15 is in the range of 0.3 to 0.6, it can effectively solve the problem of air binding of the centrifugal pump and ensure that it does not have a negative impact on the liquid delivery pump.

[0047] Figure 7 FIG. 2 shows an exploded schematic diagram of a liquid delivery pump according to an embodiment of the present invention. Figure 7, first insert the pump shaft 17 into the top groove 1261 of the column 126 at the top of the outward protrusion 124 in the second housing 12. The pump shaft 17 can be made of ceramic material, for example, or can be made of other materials with good corrosion resistance, wear resistance and high hardness. Then, the pump shaft 17 is passed through the hollow body 131 of the impeller assembly 13 so that the impeller assembly 13 is sleeved on the pump shaft 17 and the column 126 is inserted into the hollow body 131. Since the rotor 162 and the impeller assembly 13 are integrated, the pump shaft 17 also passes through the hollow part 1621 of the rotor 162 so that the rotor 162 is sleeved on the pump shaft 17. Finally, the first housing 11 that has accommodated the stator 161 (not shown) is sleeved on the outside of the integrated rotor 162 and impeller assembly 13 and fixedly installed on the second housing 12. The first housing 11 and the second housing 12 can be installed together in a variety of suitable ways, such as screw connection, snap connection or rigid connection. When the liquid delivery pump 10 is working, the rotor 162 and the impeller assembly 13 will rotate around the pump shaft 17 as the center.

[0048] Figure 8 A cross-sectional view of a liquid delivery pump according to another embodiment of the present invention is shown; Fig. 9 FIG. 2 shows a bottom schematic diagram of a liquid delivery pump according to another embodiment of the present invention. Figure 8 and Fig. 9 The exemplary liquid delivery pump 20 includes a first housing 21, a second housing 22, an impeller assembly 23, and a drive assembly 26. The second housing 22 includes a pump inlet 221, a pump outlet 222, and a pump cavity 223 that fluidly connects the pump inlet 221 and the pump outlet 222. The second housing 22 may also include a mouth 224 extending outwardly, and the pump inlet 221 is formed around the mouth 224.

[0049] The mouth 224 is also formed with a plurality of grooves 225 (e.g., four grooves) distributed in the circumferential direction of the shaft. It is understood that the number of the grooves 225 is not limited to four, and the number can be set according to actual needs. The grooves 225 can allow the liquid to enter the pump chamber 223 from the pump inlet 221 in advance and contact the impeller assembly 23 when the liquid delivery pump 20 is not working, so that part of the air in the pump chamber 223 can be discharged from the grooves 225.

[0001] The impeller assembly 23 is at least partially disposed in the pump cavity 223 of the second housing 22. The impeller assembly 23 includes a centrifugal impeller 24 and an axial flow impeller 25 coaxially connected in series with the centrifugal impeller 24. The axial flow impeller 25 may be disposed adjacent to the mouth 224 of the second housing 22.

[0002] In one embodiment, the axial flow impeller 25 may further include axial flow blades 251 and an axial flow hub 252, wherein the axial flow blades 251 are axially spaced apart and arranged on the axial flow hub 252. The number of the axial flow blades 251 may be two or more, which may be set according to actual needs.

[0003] The driving assembly 26 is at least partially disposed in the accommodating chamber 211 of the first housing 21 to drive the impeller assembly 23 to operate. In one embodiment, the driving assembly 26 can drive the axial flow impeller 25 to rotate so as to suck the liquid from the pump inlet 221 into the pump chamber 223, and drive the centrifugal impeller 24 to rotate so as to deliver the liquid sucked by the axial flow impeller 25 to the pump outlet 222 via the pump chamber 223. When the driving assembly 26 drives the axial flow impeller 25 to rotate, the axial flow impeller 25 will suck the liquid from the outside of the liquid delivery pump 20 into the pump inlet 221 through the axial force generated by its rotation. Since the axial flow impeller 25 generates self-priming force when rotating, a negative pressure can be formed at the pump inlet 221, which helps the liquid to quickly fill the pump chamber 223, so that the air originally existing in the pump chamber 223 is pushed to the pump outlet 222 by the liquid flow and discharged, ensuring that no air is retained in the pump chamber 223. At the same time, the liquid flows upward along the outer axial direction of the axial flow hub 252 of the axial flow impeller 25 and enters the centrifugal impeller 24 through the opening 241 at the bottom of the centrifugal impeller 24. Under the rotation of the axial flow impeller 25, the air in the pump chamber 223 is removed and filled with liquid. The centrifugal force generated when the driving component 26 drives the centrifugal impeller 24 to rotate further pressurizes the liquid in the pump chamber 223 and pushes the liquid to the pump outlet 222, and finally the liquid is discharged from the pump outlet 222.

[0050] In one embodiment, the drive assembly 26 may be a brushless DC motor. A brushless DC motor generally has no carbon brushes, which can reduce wear, thereby improving motor efficiency and reliability, and also has the advantage of low noise. However, in other embodiments, the drive assembly 26 may also be other types of motors or structures with a driving function.

[0051] In one embodiment, the accommodating chamber 211 defined by the first housing 21 may further include a first sub-chamber 211a and a second sub-chamber 211b. The stator 261 of the brushless DC motor may be disposed in the first sub-chamber 211a. The rotor 262 of the brushless DC motor may be disposed in the second sub-chamber 211b.

[0052] In one embodiment, the drive assembly 26 may further include a drive shaft 263, which is fixedly connected to the rotor 262 via a first bearing 27. The drive shaft 263 may be made of, for example, a ceramic material, or may be made of other materials having good corrosion resistance, wear resistance, and high hardness. The top of the drive shaft 263 is fixed in the second sub-chamber 211b via a second bearing 28, and both the first bearing 27 and the second bearing 28 may be made of, for example, a graphite material, or may be made of other materials having good self-lubrication, chemical stability, and high temperature resistance. When the rotor 262 continuously rotates due to the electromagnetic torque, the drive shaft 263 is driven to rotate, and further the impeller assembly 23 coaxially connected in series on the drive shaft 263 is driven to rotate.

[0053] Fig.10 FIG. 2 shows an exploded schematic diagram of a liquid delivery pump according to another embodiment of the present invention. Fig.10 , first, the centrifugal impeller 24 is sleeved on the lower end of the drive shaft 263 fixedly connected to the rotor 262 through the centrifugal hollow part 242 of the centrifugal impeller 24. Then, the axial flow impeller 25 is sleeved on the lower end of the aforementioned drive shaft 263 through the hollow part 253 of the axial flow hub 252. Both the centrifugal impeller 24 and the axial flow impeller 25 can be installed on the drive shaft 263 using a snap-on or other suitable fixed connection method. Finally, the first housing 21 that has accommodated the stator 261 (not shown) is sleeved on the outside of the aforementioned liquid delivery pump 20 and fixedly installed on the second housing 22. The first housing 21 and the second housing 22 can be installed together in a variety of suitable ways, for example, screw connection, snap connection or rigid connection. When the liquid delivery pump 20 is working, the rotor 262 drives the centrifugal impeller 24 and the axial flow impeller 25 connected to the same drive shaft 263 to work, so that the centrifugal impeller 24 and the axial flow impeller 25 maintain the same speed.

[0054] The present invention can solve the air binding problem without adding additional water pipes or nozzles, and also improves the practicality and economy of the liquid delivery pump. By adding an axial flow pump at the front end of the centrifugal pump, the air inside the pump chamber and the impeller is forced out before the liquid delivery pump is started, avoiding the air binding of the centrifugal pump not only improves the reliability and stability of the liquid delivery pump, but also extends the service life of the liquid delivery pump and reduces maintenance costs. Secondly, the technical solution uses the same speed to drive the centrifugal pump and the axial flow pump, which simplifies the design of the equipment and reduces the complexity and cost of the equipment.

[0055] The above description is only an optional embodiment of the embodiment of the present invention and is not intended to limit the embodiment of the present invention. For those skilled in the art, the embodiment of the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment of the present invention shall be included in the protection of the embodiment of the present invention.

[0056] Although embodiments of the present invention have been described with reference to several specific embodiments, it should be understood that embodiments of the present invention are not limited to the disclosed specific embodiments. Embodiments of the present invention are intended to cover various modifications and equivalent arrangements included in the spirit and scope of the appended claims. The scope of the appended claims is consistent with the broadest interpretation, thereby including all such modifications and equivalent structures and functions.

Claims

1. A liquid delivery pump, comprising: A first housing defining a receiving chamber; a second housing including a pump inlet, a pump outlet, and a pump chamber in fluid communication with the pump inlet and the pump outlet; an impeller assembly, including a centrifugal impeller and an axial flow impeller, which is at least partially disposed in the pump cavity of the second housing; The impeller assembly includes a hollow body, the hollow body includes a first end adjacent to the pump inlet and a second end opposite to the first end and away from the pump inlet, the axial flow impeller is formed at the first end of the hollow body, and the centrifugal impeller is formed at the second end of the hollow body; A driving assembly is at least partially disposed in the accommodating cavity of the first housing, and the driving assembly is configured to drive the impeller assembly to operate.

2. The liquid delivery pump according to claim 1, characterized in that: The driving assembly is configured to drive the axial flow impeller to rotate so as to draw liquid from the pump inlet into the pump chamber, and to drive the centrifugal impeller to rotate so as to transport the liquid drawn by the axial flow impeller to the pump outlet via the pump chamber.

3. The liquid delivery pump according to claim 2, characterized in that: The impeller assembly is integrally formed, and the axial flow impeller and the centrifugal impeller rotate coaxially.

4. The liquid delivery pump according to claim 1, characterized in that: The second end of the hollow body includes a disc-shaped portion extending radially outward, the centrifugal impeller includes a plurality of centrifugal blades arranged circumferentially at intervals on the disc-shaped portion, and the axial flow impeller includes a plurality of axial flow blades arranged circumferentially at intervals on the inner wall of the first end.

5. The liquid delivery pump according to claim 1, characterized in that: The driving assembly includes a brushless DC motor.

6. The liquid delivery pump according to claim 5, characterized in that: The accommodating cavity of the first housing includes a first sub-cavity and a second sub-cavity. The stator of the brushless DC motor is disposed in the first sub-cavity. The rotor of the brushless DC motor is disposed in the second sub-cavity and is coupled to the impeller assembly.

7. The liquid delivery pump according to claim 1, characterized in that: The second housing includes an outward protrusion adjacent to the axial flow impeller, and a through hole is formed on a side of the outward protrusion to define the pump inlet.

8. The liquid delivery pump according to claim 7, characterized in that: A column is formed on the top of the outward protrusion and is inserted into the hollow body from the first end.

9. A liquid delivery pump, comprising: A first housing defining a receiving chamber; A second housing, comprising a pump inlet, a pump outlet, and a pump chamber in fluid communication with the pump inlet and the pump outlet, wherein the pump inlet is surrounded by a mouth extending outward from the second housing, and the mouth is formed with circumferentially distributed grooves; an impeller assembly at least partially disposed within the pump chamber of the second housing, the impeller assembly comprising a centrifugal impeller and an axial flow impeller coaxially connected in series with the centrifugal impeller, the axial flow impeller being arranged adjacent to the mouth of the second housing; A driving assembly is at least partially disposed in the accommodating cavity of the first housing, and the driving assembly is configured to drive the impeller assembly to operate.

10. The liquid delivery pump according to claim 9, characterized in that: The driving assembly is configured to drive the axial flow impeller to rotate so as to draw liquid from the pump inlet into the pump chamber, and to drive the centrifugal impeller to rotate so as to transport the liquid drawn by the axial flow impeller to the pump outlet via the pump chamber.

11. The liquid delivery pump according to claim 9, characterized in that: The driving assembly comprises a driving shaft, and the centrifugal impeller and the axial flow impeller are sleeved on the driving shaft.

12. The liquid delivery pump according to any one of claims 9 to 11, characterized in that: The driving assembly includes a brushless DC motor.

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