LNG immersed pump

Abstract

The utility model discloses an LNG (Liquefied Natural Gas) immersed pump, which belongs to the field of immersed pump equipment and comprises a pump body, a lower bearing, an upper bearing, a stator, a main shaft, an impeller pressurizing structure, a first flow guide pipe and a second flow guide pipe, the impeller pressurizing structure comprises a pressurizing shell and a pressurizing impeller; a pressurizing cavity is formed in the pressurizing shell; the front end of the main shaft exceeds the front end of the pump body and is rotatably mounted in the middle of the booster cavity; the pressurizing impeller is used for being driven by the main shaft to rotate and pressurizing the LNG liquid entering the pressurizing cavity; the first flow guide pipe and the second flow guide pipe are located on the upper side and the lower side of the pump body correspondingly and communicate with the interior of the booster cavity. A first flow guide channel and a second flow guide channel are further formed in the pump body; the first flow guide channel is used for guiding LNG liquid flowing through the first flow guide pipe into the lower bearing, and the second flow guide channel is used for guiding LNG liquid flowing through the second flow guide pipe into the upper bearing. According to the utility model, the lubricating effect of the bearing can be guaranteed, and the lubricating requirements on the bearing under different working conditions are met.

Description

Technical Field

[0001] The utility model belongs to the field of submersible pump equipment, in particular to a LNG submersible pump. Background Art

[0002] LNG is the abbreviation of liquefied natural gas, the main component of which is methane. It is colorless, odorless, non-toxic and non-corrosive, and is recognized as the cleanest fossil energy on earth. LNG submersible pump is a pump equipment used to transport liquefied natural gas and related cryogenic liquids. It has been widely used due to its small size, low noise, long service life, easy installation, no terrain restrictions and the ability to work below the liquid surface.

[0003] Taking into account factors such as fluid, pressure, effective sealing between pump and pump cover, installation and maintenance, most current LNG submersible pumps are installed in a vertical suspension to improve the effective working efficiency of the pump. However, current general LNG submersible pumps have problems such as long process pipelines, many elbows, insufficient pipe diameter, and poor return and liquid discharge. As a result, the pump pool outside the pump body cannot be completely filled with liquid regardless of whether it is at a high or low liquid level, which in turn causes the bearings to not be completely immersed and wetted, resulting in dry grinding, which accelerates the damage of the bearings and affects the normal operation of the submersible pump.

[0004] The patent with application number 201310548690.X discloses an LNG submersible pump, which improves the overall performance of the pump by increasing the pressure of the impeller by adding an inducer, thereby improving the wear resistance of the bearing under low temperature of LNG, reducing the deformation of the bearing, and extending the service life of the bearing. However, since the patent is in high head, high speed, and large flow conditions when in use, even if the liquid is filled in the pump body in advance, the liquid level in the pump will drop as the pump operation time increases, causing the upper bearing in the pump body to be dry-grinded because it cannot be completely immersed in the liquid; and the patent does not take into account that when the liquid in the pump pool is at a low liquid level, it will be difficult to pressurize the pump body, resulting in less liquid being sucked into the pump, resulting in the upper bearing being unable to be immersed, and the lower bearing can only be half immersed at most, and the upper and lower bearings cannot be effectively lubricated, and the bearing wear is serious. It can be seen that the patent does not solve the problem that the bearing cannot be completely immersed in the LNG low-temperature liquid due to changes in the working conditions during the operation of the pump, which then causes dry grinding. After the bearings are worn, they may become loose, vibrate, make abnormal noises, or even fall off, which may damage the motor coil, shaft, impeller, etc. It may also easily cause pump cavitation and the inability to generate pressure, which seriously affects the liquid filling efficiency and shortens the service life of the submersible pump. Therefore, there is an urgent need to provide an LNG submersible pump that can solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to provide an LNG submersible pump to address the above shortcomings, and to solve the problem that the bearings of the current submersible pumps are worn because they cannot be completely immersed in liquid. To achieve the above purpose, the utility model provides the following technical solutions:

[0006] An LNG submersible pump comprises a pump body, wherein the pump body comprises a lower bearing, an upper bearing, a stator and a main shaft rotatably mounted in the middle of the pump body, and further comprises an impeller boosting structure, a first guide pipe and a second guide pipe; the impeller boosting structure comprises a boosting housing and a boosting impeller; the boosting housing is arranged at the front side of the pump body and has a boosting chamber inside; the front end of the main shaft exceeds the front end of the pump body and is rotatably mounted in the middle of the boosting chamber; the boosting impeller is mounted on the side wall of the main shaft located in the boosting chamber; the boosting impeller is used to be driven by the main shaft to rotate and generate centrifugal force centrifugal force, thereby pressurizing the LNG liquid introduced into the boosting chamber; the first guide pipe and the second guide pipe are both arranged parallel to the main shaft; the first guide pipe and the second guide pipe are respectively located on the upper side and the lower side of the pump body, and are connected to the inside of the boosting chamber through the rear side wall of the boosting shell; the pump body is also provided with a first guide channel and a second guide channel; the first guide channel is used to guide the LNG liquid flowing through the first guide pipe into the lower bearing from the front end of the lower bearing, and the second guide channel is used to guide the LNG liquid flowing through the second guide pipe into the upper bearing from the rear end of the upper bearing.

[0007] Furthermore, the shape of the boost chamber is cylindrical; the rear side wall of the boost shell is a straight wall, and two liquid outlets are symmetrically provided at the upper part and the lower part of the rear side wall of the boost shell; the front end of the first guide pipe is connected to the liquid outlet located at the upper part of the rear side wall of the boost shell, and the front end of the second guide pipe is connected to the liquid outlet located at the upper part of the rear side wall of the boost shell.

[0008] Furthermore, a first liquid inlet hole is provided at the front end of the lower bearing, and a first liquid outlet hole is provided at the rear end of the lower bearing; the first guide channel includes a first guide section and a second guide section; the first guide section is used to transport the LNG liquid flowing through the first guide pipe to the second guide section; the second guide section is used to allow the LNG liquid to enter the interior of the lower bearing through the first liquid inlet hole, and then be discharged from the first liquid outlet hole.

[0009] Furthermore, a liquid leakage partition is provided in the first liquid outlet hole; the outer wall of the liquid leakage partition is configured as a sawtooth structure; and a liquid leakage gap is formed between the outer wall of the liquid leakage partition and the inner wall of the first liquid outlet hole.

[0010] Furthermore, a second liquid inlet hole is provided at the rear end of the upper bearing, and a second liquid outlet hole is provided at the front end of the upper bearing; the second guide channel includes a third guide section and a fourth guide section; the third guide section is used to transport the LNG liquid flowing through the second guide pipe to the fourth guide section; the fourth guide section is used to allow the LNG liquid to enter the interior of the upper bearing through the second liquid inlet hole and be discharged from the second liquid outlet hole.

[0011] Furthermore, the fourth guide section is also provided with a nozzle for spraying LNG liquid into the interior of the upper bearing.

[0012] Furthermore, a liquid leakage partition is provided in the second liquid outlet through hole; the outer wall of the liquid leakage partition is a sawtooth structure; and a liquid leakage gap is formed between the outer wall of the liquid leakage partition and the inner wall of the second liquid outlet through hole.

[0013] Furthermore, the pump body also has an installation cavity located between the upper bearing and the lower bearing; the installation cavity is provided with a first opening on the side wall near the front of the lower bearing, and the installation cavity is provided with a second opening on the side wall near the rear of the upper bearing.

[0014] Furthermore, the stator is arranged in the installation cavity, and the side wall of the stator is provided with a plurality of leakage grooves along the circumferential direction, and the leakage grooves are used to discharge the LNG liquid accumulated at the rear of the installation cavity from the leakage grooves to the front of the installation cavity.

[0015] Furthermore, it also includes two connecting rods; the two connecting rods are respectively fixed to the upper and lower parts of the pump body; the front ends of the two connecting rods are respectively fixed to the upper and lower sides of the rear side wall of the supercharger housing.

[0016] The beneficial effects of the utility model are:

[0017] 1. The utility model provides two independent LNG liquid delivery channels to separately soak the upper bearing and the lower bearing, and ensures that the upper bearing and the lower bearing are soaked in LNG liquid when the pump body is working, so that the bearing cooling and lubrication effects are good, the bearing wear is reduced, and the service life of the bearing is extended.

[0018] 2. The utility model utilizes the main shaft in the pump body to drive the boost impeller to rotate. It does not need to configure an additional drive structure, which can save energy and simplify the structure. It can also meet the cooling and lubrication requirements of the upper bearing and the lower bearing of the pump body at different speeds, and the design is ingenious. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the utility model;

[0020] Figure 2 This utility model Figure 1 Schematic diagram of structure A;

[0021] Figure 3 This utility model Figure 1 Schematic diagram of structure B;

[0022] Figure 4 It is a structural schematic diagram of the stator of the utility model;

[0023] In the accompanying drawings: 1-pump body, 2-lower bearing, 3-upper bearing, 4-stator, 5-main shaft, 6-impeller boost structure, 7-first guide tube, 8-second guide tube, 9-leakage baffle, 11-first guide channel, 12-second guide channel, 13-installation cavity, 14-connecting rod, 21-first liquid inlet hole, 22-first liquid outlet hole, 31-second liquid inlet hole, 32-second liquid outlet hole, 41-leakage groove, 61-boost housing, 62-boost impeller, 131-first opening, 132-second opening, 611-boost cavity. DETAILED DESCRIPTION

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0025] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", "some examples", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods, but the present invention is not limited to the following embodiments.

[0027] Embodiment 1:

[0028] See attached Figures 1-2. An LNG submersible pump comprises a pump body 1, wherein the pump body 1 comprises a lower bearing 2, an upper bearing 3, a stator 4 and a main shaft 5 rotatably mounted in the middle of the pump body 1, and further comprises an impeller boosting structure 6, a first guide pipe 7 and a second guide pipe 8; the impeller boosting structure 6 comprises a boosting housing 61 and a boosting impeller 62; the boosting housing 61 is arranged at the front side of the pump body 1 and has a boosting chamber 611 inside; the front end of the main shaft 5 exceeds the front end of the pump body 1 and is rotatably mounted in the middle of the boosting chamber 611; the boosting impeller 62 is mounted on the side wall of the main shaft 5 located in the boosting chamber 611; the boosting impeller 62 is used to be driven by the main shaft 5 to rotate And generate centrifugal force, thereby pressurizing the LNG liquid introduced into the boosting chamber 611; the first guide pipe 7 and the second guide pipe 8 are both arranged parallel to the main shaft 5; the first guide pipe 7 and the second guide pipe 8 are respectively located on the upper and lower sides of the pump body 1, and are connected to the inside of the boosting chamber 611 through the rear side wall of the boosting housing 61; the pump body 1 is also provided with a first guide channel 11 and a second guide channel 12; the first guide channel 11 is used to guide the LNG liquid flowing through the first guide pipe 7 from the front end of the lower bearing 2 into the lower bearing 2; the second guide channel 12 is used to guide the LNG liquid flowing through the second guide pipe 8 from the rear end of the upper bearing 3 into the upper bearing 3. It can be seen from the above structure that the general pump body 1 will be placed vertically in the pump pool when in use. The lower bearing 2, the upper bearing 3, and the stator 4 are all arranged inside the pump body 1, and the lower bearing 2 is located below the upper bearing 3, and the stator 4 is located between the lower bearing 2 and the upper bearing 3. The main shaft 5 is rotatably mounted in the middle of the pump body 1. When the main shaft 5 rotates, it can drive the various impellers inside the pump body 1 to rotate. The impeller boosting structure 6 is used to introduce LNG liquid that can be used to lubricate and cool bearings from an external pump pool, and to boost the LNG liquid. The impeller boosting structure 6 includes a boosting housing 61 and a boosting impeller 62. The boosting housing 61 is arranged on the front side of the pump body 1, and a boosting chamber 611 is provided inside the boosting housing 61. A liquid inlet may be provided on the boosting housing 61, so that the LNG liquid in the pump pool outside the boosting housing 61 enters the boosting chamber 611, and then the LNG liquid in the boosting chamber 611 is boosted by the boosting impeller 62 driven to rotate by the main shaft 5. Since the boost impeller 62 is installed on the side wall of the main shaft 5 located in the boost chamber 611, when the pump body 1 is working normally, the main shaft 5 will not only drive the impeller in the pump to rotate, but also drive the boost impeller 62 to rotate at the same time. Therefore, the utility model does not need an additional driving structure to drive the boost impeller 62 to rotate, which can save energy and simplify the structure. Moreover, when the boost impeller 62 rotates, a certain negative pressure will be generated inside the boost chamber 611. As long as there is still a certain amount of LNG liquid at the bottom of the pump pool, it can be continuously sucked into the boost chamber 611. In addition, as the working condition of the pump body 1 changes, the speed of the main shaft 5 will be increased or decreased, and the speed of the boost impeller 62 will change with the change of the main shaft 5.For example, when the speed of the main shaft 5 is increased, the speed of the boost impeller 62 is increased, the negative pressure in the boost chamber 611 is increased, more LNG liquid is sucked into the boost chamber 611, and is delivered to the upper bearing 3 or the lower bearing 2 more quickly after being pressurized. Since more LNG liquid is needed to cool and lubricate the bearings when the speed of the pump body 1 is high, the design of the boost impeller 62 of the utility model can ensure the cooling and lubrication requirements of the pump body 1 for the bearings under high speed conditions, and the same is true when the speed is low. It can be seen that the utility model can also meet the cooling and lubrication requirements of the upper and lower bearings of the pump body 1 under different speed conditions, and the design is ingenious. The first guide pipe 7 and the second guide pipe 8 are both connected to the inside of the boost chamber 611 through the rear side wall of the boost housing 61, so that the pressurized LNG liquid is respectively input into the first guide pipe 7 or the second guide pipe 8. The first guide pipe 7 and the second guide pipe 8 are independently arranged outside the pump body 1, respectively located on the upper and lower sides of the pump body 1, and are both arranged parallel to the main shaft 5. Then, the LNG liquid flowing through the first guide pipe 7 can be introduced into the lower bearing 2 from the front end of the lower bearing 2 through the first guide channel 11, and the lower bearing 2 is immersed, so as to achieve cooling and lubrication of the lower bearing 2; or the LNG liquid flowing through the second guide pipe 8 can be introduced into the upper bearing 3 from the rear end of the upper bearing 3 through the second guide channel 12, and the upper bearing 3 is immersed, so as to achieve cooling and lubrication of the upper bearing 3. The utility model provides two independent LNG liquid delivery channels for the lower bearing 2 and the upper bearing 3, so as to ensure that the upper bearing and the lower bearing are immersed in the LNG liquid when the pump body 1 is working, and the bearing cooling and lubrication effect is good, which can reduce the bearing wear and extend the service life of the bearing.

[0029] Embodiment 2:

[0030] See attached Figures 1 to 4 On the basis of the first embodiment, the shape of the boosting chamber 611 is cylindrical; the rear side wall of the boosting shell 61 is a straight wall, and two liquid outlets are symmetrically arranged at the upper and lower parts of the rear side wall of the boosting shell 61; the front end of the first guide pipe 7 is connected to the liquid outlet located at the upper part of the rear side wall of the boosting shell 61, and the front end of the second guide pipe 8 is connected to the liquid outlet located at the upper part of the rear side wall of the boosting shell 61. It can be seen from the above structure that since the boosting impeller 62 is arranged in the middle of the boosting chamber 611, two liquid outlets are symmetrically arranged at the upper and lower parts of the rear side wall of the boosting shell 61, so that the LNG liquid inside the cylindrical boosting chamber 611 can be diverted to the upper and lower sides of the boosting chamber 611 after boosting, and outputted to the first guide pipe 7 or the second guide pipe 8 from the two liquid outlets on the rear side wall of the boosting shell 61 as a straight wall at the same time, so as to ensure that the pressure of the pressurized LNG liquid is consistent when it is outputted to the first guide pipe 7 or the second guide pipe 8.

[0031] The front end of the lower bearing 2 is provided with a first liquid inlet hole 21, and the rear end of the lower bearing 2 is provided with a first liquid outlet hole 22; the first guide channel 11 includes a first guide section and a second guide section; the first guide section is used to transport the LNG liquid flowing through the first guide pipe 7 to the second guide section; the second guide section is used to allow the LNG liquid to enter the interior of the lower bearing 2 through the first liquid inlet hole 21, and then be discharged from the first liquid outlet hole 22. As can be seen from the above structure, the LNG liquid flowing through the first guide pipe 7 first enters the first guide channel 11, and then is transported from the first guide channel 11 to the first liquid inlet hole 21, slowly fills the interior of the lower bearing 2 from the front end, and then is discharged from the first liquid outlet hole 22 provided at the rear end of the lower bearing 2, so as to achieve the immersion of the lower bearing 2 and ensure the cooling and lubrication effect of the lower bearing 2.

[0032] A leakage baffle 9 is provided in the first liquid outlet hole 22; the outer wall of the leakage baffle 9 is a sawtooth structure; a leakage gap is formed between the outer wall of the leakage baffle 9 and the inner wall of the first liquid outlet hole 22. As can be seen from the above structure, the provision of the leakage baffle 9 can slow down the speed at which the LNG liquid is discharged from the first liquid outlet hole 22 of the lower bearing 2, so that the LNG liquid entering the lower bearing 2 can fully lubricate and cool the lower bearing 2.

[0033] Embodiment three:

[0034] See attached Figures 1 to 4 . On the basis of the second embodiment, the rear end of the upper bearing 3 is provided with a second liquid inlet hole 31, and the front end of the upper bearing 3 is provided with a second liquid outlet hole 32; the second guide channel 12 includes a third guide section and a fourth guide section; the third guide section is used to transport the LNG liquid flowing through the second guide pipe 8 to the fourth guide section; the fourth guide section is used to allow the LNG liquid to enter the interior of the upper bearing 3 through the second liquid inlet hole 31, and be discharged from the second liquid outlet hole 32. It can be seen from the above structure that the LNG liquid flowing through the second guide pipe 8 first enters the second guide channel 12, and then is transported from the second guide channel 12 to the second liquid inlet hole 31, fills the interior of the upper bearing 3 from the rear end, and then is discharged from the second liquid outlet hole 32 provided at the front end of the upper bearing 3, so as to achieve the immersion of the upper bearing 3 and ensure the cooling and lubrication effect of the upper bearing 3.

[0035] The fourth guide section is also provided with a nozzle for spraying LNG liquid into the interior of the upper bearing 3. As can be seen from the above structure, the provision of the nozzle can spray the LNG liquid into the interior of the upper bearing 3 more uniformly.

[0036] A leakage baffle 9 is provided in the second liquid outlet hole 32; the outer wall of the leakage baffle 9 is a sawtooth structure; a leakage gap is formed between the outer wall of the leakage baffle 9 and the inner wall of the second liquid outlet hole 32. As can be seen from the above structure, the provision of the leakage baffle 9 can slow down the speed at which the LNG liquid is discharged from the second liquid outlet hole 32 of the upper bearing 3, so that the LNG liquid entering the upper bearing 3 can fully lubricate and cool the upper bearing 3.

[0037] The pump body 1 also has an installation cavity 13 located between the upper bearing 3 and the lower bearing 2; the installation cavity 13 is provided with a first opening 131 on the side wall near the front of the lower bearing 2, and the installation cavity 13 is provided with a second opening 132 on the side wall near the rear of the upper bearing 3. As can be seen from the above structure, the installation cavity 13 is used to provide installation space for structures such as the stator 4 and the rotor, and the installation cavity 13 is provided with a first opening 131 on the side wall near the front of the lower bearing 2, and the first opening 131 is used to discharge the LNG liquid that flows through the lower bearing 2 and enters the front of the installation cavity 13 out of the pump body 1 and then returns to the pump pool. The installation cavity 13 is provided with a second opening 132 on the side wall near the rear of the upper bearing 3, and the second opening 132 is used to discharge the LNG liquid that flows through the upper bearing 3 and enters the rear of the installation cavity 13 out of the pump body 1 and then returns to the pump pool.

[0038] The stator 4 is arranged in the installation cavity 13, and the side wall of the stator 4 is provided with a plurality of leakage grooves 41 along the circumferential direction, and the leakage grooves 41 are used to discharge the LNG liquid accumulated in the rear part of the installation cavity 13 from the leakage grooves 41 to the front part of the installation cavity 13. From the above structure, it can be known that since the front and rear ends of the stator 4 have a liquid receiving portion with a trapezoidal cross section, the LNG liquid leaked from the front end of the upper bearing 3 will first enter the liquid receiving portion at the rear end of the stator 4, and will overflow into the installation cavity 13 only after the liquid receiving portion at the rear end of the stator 4 is filled with liquid. The side wall of the stator 4 is provided with a plurality of leakage grooves 41 along the circumferential direction, and at this time, a part of the LNG liquid accumulated in the rear part of the installation cavity 13 can be discharged from the leakage grooves 41 to the front part of the installation cavity 13.

[0039] It also includes two connecting rods 14; the two connecting rods 14 are respectively fixed to the upper and lower parts of the pump body 1; the front ends of the two connecting rods 14 are respectively fixed to the upper and lower sides of the rear side wall of the boost housing 61. From the above structure, it can be seen that the boost housing 61 is fixedly connected to the pump body 1 through the two connecting rods 14, and the two connecting rods 14 are respectively fixed to the upper and lower parts of the pump body 1, which can ensure the stability after connection.

[0040] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An LNG submersible pump, comprising a pump body (1), wherein the pump body (1) comprises a lower bearing (2), an upper bearing (3), a stator (4) and a main shaft (5) rotatably mounted in the middle of the pump body (1), characterized in that: The invention comprises an impeller boosting structure (6), a first flow guide pipe (7) and a second flow guide pipe (8); the impeller boosting structure (6) comprises a boosting shell (61) and a boosting impeller (62); the boosting shell (61) is arranged at the front side of the pump body (1) and has a boosting chamber (611) inside; the front end of the main shaft (5) exceeds the front end of the pump body (1) and is rotatably mounted in the middle of the boosting chamber (611); the boosting impeller (62) is mounted on the side wall of the main shaft (5) located in the boosting chamber (611); the boosting impeller (62) is used to be driven by the main shaft (5) to rotate and generate centrifugal force, thereby boosting the LNG liquid introduced into the boosting chamber (611); the first boosting impeller (62) is used to be driven by the main shaft (5) to rotate and generate centrifugal force, thereby boosting the LNG liquid introduced into the boosting chamber (611); the second ... used to be driven by the main shaft (5) to rotate and generate centrifugal force; the first boosting impeller (62) is used to be used to boost the LNG liquid introduced into the boosting chamber (611); the second boosting impeller (62) is used to be used to boost the LNG liquid introduced into the boosting chamber (611); the first boosting impeller (62) is used to be used to boost the LNG liquid introduced into the boosting chamber (611); the second boosting impeller (62) is used to be used to A flow guide pipe (7) and a second flow guide pipe (8) are both arranged parallel to the main shaft (5); the first flow guide pipe (7) and the second flow guide pipe (8) are respectively located on the upper side and the lower side of the pump body (1), and are both connected to the inside of the boost chamber (611) through the rear side wall of the boost housing (61); a first flow guide channel (11) and a second flow guide channel (12) are also provided in the pump body (1); the first flow guide channel (11) is used to guide the LNG liquid flowing through the first flow guide pipe (7) from the front end of the lower bearing (2) into the lower bearing (2); the second flow guide channel (12) is used to guide the LNG liquid flowing through the second flow guide pipe (8) from the rear end of the upper bearing (3) into the upper bearing (3).

2. The LNG submersible pump according to claim 1, characterized in that: The boost chamber (611) is cylindrical in shape; the rear side wall of the boost shell (61) is a straight wall, and two liquid outlets are symmetrically provided at the upper and lower parts of the rear side wall of the boost shell (61); the front end of the first flow guide tube (7) is connected to the liquid outlet located at the upper part of the rear side wall of the boost shell (61), and the front end of the second flow guide tube (8) is connected to the liquid outlet located at the upper part of the rear side wall of the boost shell (61).

3. The LNG submersible pump according to claim 1, characterized in that: The front end of the lower bearing (2) is provided with a first liquid inlet through hole (21), and the rear end of the lower bearing (2) is provided with a first liquid outlet through hole (22); the first guide channel (11) comprises a first guide section and a second guide section; the first guide section is used to transport LNG liquid flowing through the first guide pipe (7) to the second guide section; the second guide section is used to allow the LNG liquid to enter the interior of the lower bearing (2) through the first liquid inlet through hole (21) and then be discharged from the first liquid outlet through hole (22).

4. The LNG submersible pump according to claim 3, characterized in that: A liquid leakage partition (9) is fitted in the first liquid outlet through hole (22); the outer wall of the liquid leakage partition (9) is configured as a sawtooth structure; and a liquid leakage gap is formed between the outer wall of the liquid leakage partition (9) and the inner wall of the first liquid outlet through hole (22).

5. The LNG submersible pump according to claim 1, characterized in that: The rear end of the upper bearing (3) is provided with a second liquid inlet through hole (31), and the front end of the upper bearing (3) is provided with a second liquid outlet through hole (32); the second guide channel (12) comprises a third guide section and a fourth guide section; the third guide section is used to transport LNG liquid flowing through the second guide pipe (8) to the fourth guide section; the fourth guide section is used to allow LNG liquid to enter the interior of the upper bearing (3) through the second liquid inlet through hole (31) and be discharged from the second liquid outlet through hole (32).

6. The LNG submersible pump according to claim 5, characterized in that: The fourth guide section is also provided with a nozzle for spraying LNG liquid into the interior of the upper bearing (3).

7. The LNG submersible pump according to claim 5, characterized in that: A liquid leakage partition (9) is fitted in the second liquid outlet through hole (32); the outer wall of the liquid leakage partition (9) is a sawtooth structure; and a liquid leakage gap is formed between the outer wall of the liquid leakage partition (9) and the inner wall of the second liquid outlet through hole (32).

8. The LNG submersible pump according to claim 1, characterized in that: The pump body (1) further comprises an installation cavity (13) located between the upper bearing (3) and the lower bearing (2); the installation cavity (13) is provided with a first opening (131) on a side wall near the front of the lower bearing (2), and the installation cavity (13) is provided with a second opening (132) on a side wall near the rear of the upper bearing (3).

9. The LNG submersible pump according to claim 8, characterized in that: The stator (4) is arranged in the installation cavity (13), and a plurality of leakage grooves (41) are arranged on the side wall of the stator (4) along the circumferential direction. The leakage grooves (41) are used to discharge LNG liquid accumulated at the rear of the installation cavity (13) from the leakage grooves (41) to the front of the installation cavity (13).

10. The LNG submersible pump according to claim 1, characterized in that: It also includes two connecting rods (14); the two connecting rods (14) are respectively fixed to the upper and lower parts of the pump body (1); the front ends of the two connecting rods (14) are respectively fixed to the upper and lower sides of the rear side wall of the boost housing (61).

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