A cryogenic submersible pump with a guide vane ring installed inside

Abstract

The present invention provides a cryogenic submersible pump with a guide vane ring inside, which relates to the technical field of submersible pumps and solves the problem of relatively large impact at the outlet flow channel of the cryogenic submersible pump in the prior art. The submersible pump includes a final-stage guide vane ring and a front guide vane ring. The final-stage guide vane ring is arranged on one side close to the motor rotor of the submersible pump; there are guide vane ring blades on the front guide vane ring and the final-stage guide vane ring; the guide vane ring blades include a first outer contour and a second outer contour. A blade inlet angle is formed between the first starting arc of the first outer contour and the horizontal section; a blade outlet angle is formed between the second terminating arc of the second outer contour and the horizontal section; the blade outlet angle of each guide vane ring blade is greater than its own blade inlet angle; the blade outlet angle of the final-stage guide vane ring is greater than that of the front guide vane ring. The present invention is used to reduce the flow loss in the outlet flow channel of the cryogenic submersible pump, especially to reduce the impact of the liquid on the flow channel and the pipe inlet.

Description

Technical Field

[0001] The present invention relates to the technical field of submersible pumps, and in particular to a cryogenic submersible pump provided with a diffuser ring inside. Background Art

[0002] A cryogenic submersible pump is a high-speed centrifugal liquid pump used in a cryogenic environment; when the motor drives the impeller to rotate, the impeller does work on the cryogenic medium, and the medium obtains potential energy and kinetic energy from the impeller; when the medium flows through the guiding component, part of the kinetic energy will be converted into pressure energy. The cryogenic submersible pump is mainly a power output device for cryogenic liquid media.

[0003] The applicant of the present invention has found that the prior art has at least the following technical problems:

[0004] The liquid flowing out of the last-stage impeller of the cryogenic submersible pump will form a relatively large impact on the outlet flow channel of the cryogenic submersible pump, resulting in relatively large flow losses, and at the same time, problems of noise and vibration will also occur. Summary of the Invention

[0005] The purpose of the present invention is to provide a cryogenic submersible pump provided with a diffuser ring inside, which solves the problem of relatively large impact at the outlet flow channel of the cryogenic submersible pump in the prior art. The preferred technical solutions provided by the present invention can produce many technical effects as described below.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A cryogenic submersible pump provided with a diffuser ring inside according to the present invention includes a last-stage diffuser ring and a front diffuser ring. Among them, the last-stage diffuser ring is arranged on the side close to the rotor of the submersible pump motor, the number of the front diffuser rings is at least one, and all the front diffuser rings and the last-stage diffuser ring are arranged in sequence along the axis of the submersible pump; there are diffuser ring blades on both the front diffuser ring and the last-stage diffuser ring; the diffuser ring blades include a first outer contour and a second outer contour, the first outer contour is the suction surface, and the second outer contour is the pressure surface; the first outer contour includes a first starting arc and a first ending arc, and the angle formed between the first starting arc and the horizontal section plane is the blade inlet angle; the second outer contour includes a second starting arc and a second ending arc, and the angle formed between the second ending arc and the horizontal section plane is the blade outlet angle; the blade inlet angle of each diffuser ring blade is smaller than its own blade outlet angle; the blade outlet angle of the front diffuser ring is smaller than the blade outlet angle of the last-stage diffuser ring.

[0008] Further, the range of the blade outlet angle of the last-stage diffuser ring is between 70° and 80°.

[0009] Further, the range of the blade outlet angle of the front diffuser ring is between 40° and 50°.

[0010] Further, the blade inlet angle range of the leading guide vane ring is between 2° and 5°; the blade inlet angle range of the last-stage guide vane ring is between 2° and 5°.

[0011] Further, the guide vane ring blades are formed on the outer side surface of the leading guide vane ring, and the guide vane ring blades are evenly spaced along the circumferential direction of the leading guide vane ring; the guide vane ring blades are formed on the outer side surface of the last-stage guide vane ring, and the guide vane ring blades are evenly spaced along the circumferential direction of the last-stage guide vane ring.

[0012] Further, the first outer contour is the convex profile of the guide vane ring blade, and the second outer contour is the concave profile of the guide vane ring blade; the first outer contour and the second outer contour are connected on the side close to the blade inlet angle; the guide vane ring blade further includes a third outer contour, the third outer contour is far from the connection end of the first outer contour and the second outer contour, the third outer contour of the leading guide vane ring is flush with one end surface of the leading guide vane ring, and the third outer contour of the last-stage guide vane ring is flush with one end surface of the last-stage guide vane ring; both ends of the third outer contour are respectively connected to the first outer contour and the second outer contour, and there is a smooth transition between the third outer contour and the second termination arc.

[0013] Further, the height of the last-stage guide vane ring in the axial direction is greater than the height of the leading guide vane ring in the axial direction.

[0014] Further, the height range of the leading guide vane ring is 30 cm to 35 cm; the height range of the last-stage guide vane ring is 55 cm to 60 cm.

[0015] Further, along the direction of the liquid passing through the submersible pump, the number of blades of the impeller arranged in front of the last-stage guide vane ring and adjacent to the last-stage guide vane ring is not equal to the number of guide vane ring blades on the last-stage guide vane ring; along the direction of the liquid passing through the submersible pump, the number of blades of the impeller arranged in front of the leading guide vane ring and adjacent to the leading guide vane ring is not equal to the number of guide vane ring blades on the leading guide vane ring.

[0016] Further, the number of the last-stage guide vane rings is one, and the sum of the number of the last-stage guide vane rings and the leading guide vane rings is equal to the number of impellers in the submersible pump; the impellers are spaced between the last-stage guide vane ring and the leading guide vane ring, and the liquid coming out of the inducer of the submersible pump can first flow to the impeller, and the liquid coming out of the impeller can flow to the guide vane ring adjacent to the impeller; the leading guide vane ring and the last-stage guide vane ring are respectively sleeved on the inner guide shells of the corresponding submersible pumps.

[0017] Further, a liquid inlet filter body is installed on the front outer housing of the cryogenic submersible pump, and filter holes are formed in the bottom and side walls of the liquid inlet filter body.

[0018] The cryogenic submersible pump provided by the present invention is internally provided with a guide vane ring, which increases the blade outlet angle of the last-stage guide vane ring, changes the liquid flow direction, can well convert kinetic energy into pressure energy, reduces the impact of the liquid on the outlet flow channel of the submersible pump, improves the outlet head of the pump, and thus solves the problem of relatively large impact at the outlet flow channel of the cryogenic submersible pump in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0020] Figure 1 is a schematic structural diagram of the front guide vane ring provided by the embodiment of the present invention;

[0021] Figure 2 is a schematic structural diagram of the front guide vane ring blade provided by the embodiment of the present invention;

[0022] Figure 3 is a schematic structural diagram of the last-stage guide vane ring provided by the embodiment of the present invention;

[0023] Figure 4 is a schematic structural diagram of the last-stage guide vane ring blade provided by the embodiment of the present invention;

[0024] Figure 5 is a schematic cross-sectional view of the cryogenic submersible pump internally provided with a guide vane ring provided by the embodiment of the present invention;

[0025] Figure 6 is Figure 5 partial enlarged view A of

[0026] Figure 7 is a schematic structural diagram of the cryogenic submersible pump internally provided with a guide vane ring provided by the embodiment of the present invention;

[0027] In the figure: 1 - front impeller; 2 - front guide vane ring; 3 - last-stage impeller; 4 - last-stage guide vane ring; 5 - guide vane ring blade; 51 - first outer contour; 511 - first starting arc; 512 - first ending arc; 52 - second outer contour; 521 - second starting arc; 522 - second ending arc; 53 - third outer contour; 6 - front inner guide housing; 7 - last-stage inner guide housing; 8 - last-stage outer guide housing; 9 - front outer guide housing; 10 - motor; 11 - motor housing; 12 - inducer; 13 - liquid inlet filter body; 14 - upper end cover of the motor; 15 - exhaust valve; 16 - shaft rod. Detailed implementation mode

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0029] Refer to Figures 1-7 , the present invention provides a cryogenic submersible pump with a guide vane ring provided therein, including a last-stage guide vane ring 4 and a front guide vane ring 2 (both the last-stage guide vane ring 4 and the front guide vane ring 2 are guide vane rings). Among them, the last-stage guide vane ring 4 is arranged on the side close to the rotor of the submersible pump motor. The number of the front guide vane rings 2 is at least one. All the front guide vane rings 2 and the last-stage guide vane ring 4 are arranged in sequence along the axis of the submersible pump; there are guide vane ring blades 5 on both the front guide vane ring 2 and the last-stage guide vane ring 4; the guide vane ring blade 5 includes a first outer contour 51 and a second outer contour 52. The first outer contour 51 is the suction surface, and the second outer contour 52 is the pressure surface; the first outer contour 51 includes a first starting arc 511 and a first ending arc 512. The first starting arc 511 forms a blade inlet angle with the horizontal section plane; the second outer contour 52 includes a second starting arc 521 and a second ending arc 522. The second ending arc 522 forms a blade outlet angle with the horizontal section plane; the blade inlet angle of each guide vane ring blade 5 is smaller than its own blade outlet angle; the blade outlet angle of the front guide vane ring 2 is smaller than the blade outlet angle of the last-stage guide vane ring 4. In the present invention, the blade outlet angle of the front guide vane ring 2 is set to be smaller than the blade outlet angle of the last-stage guide vane ring 4 in the submersible pump because it is considered that the liquid flowing out of the cryogenic submersible pump forms a large impact on the outlet flow channel of the submersible pump, resulting in a large flow loss, noise and vibration. Therefore, the blade outlet angle of the last-stage guide vane ring 4 is increased to change the liquid flow direction, which can well convert kinetic energy into pressure energy, reduce the impact of the liquid on the outlet flow channel of the submersible pump, and improve the outlet head of the pump.

[0030] Regarding the setting where the blade outlet angle of the leading guide vane ring 2 is smaller than that of the last-stage guide vane ring 4, considering that the leading guide vane ring 2 is arranged between two adjacent impellers, the liquid flowing out of the leading guide vane ring 2 will flow to the next-stage impeller. Therefore, it is not necessary to set the blade outlet angle of the leading guide vane ring 2 very large. In addition, the larger the blade outlet angle of the guide vane ring, the greater the height of the guide vane ring in the axial direction. If the blade outlet angle of the leading guide vane ring 2 is relatively small, it can reduce the height of the submersible pump in the axial direction to a certain extent and reduce the cost of the submersible pump.

[0031] As an optional implementation manner of the embodiment of the present invention, refer to Figure 4 , the blade outlet angle range of the last-stage guide vane ring 4 is preferably between 70° and 80°. Since the blade outlet angle is not 90°, the liquid flowing out of the last-stage guide vane ring 4 can rotate and flow, which is beneficial to the liquid flowing smoothly towards the outlet direction of the submersible pump. And when the blade outlet angle of the last-stage guide vane ring 4 is set between 70° and 80°, it can also not cause a large impact on the outlet flow channel of the submersible pump and reduce the flow loss.

[0032] As an optional implementation manner of the embodiment of the present invention, refer to Figure 2 , the blade outlet angle range of the leading guide vane ring 2 is preferably between 40° and 50°, which is convenient for the liquid flowing out of the leading guide vane ring 2 to flow to the next-stage impeller. And the outlet circulation of the leading guide vane ring 2 is basically equal to the outlet circulation of the inducer, and the impeller blade inlet has a positive incidence angle of less than 5°, so that the blade has better energy conversion performance and smaller inlet impact loss.

[0033] As an optional implementation manner of the embodiment of the present invention, refer to Figure 2 and Figure 4 , the blade inlet angle range of the leading guide vane ring 2 is between 2° and 5°; the blade inlet angle range of the last-stage guide vane ring 4 is between 2° and 5°, which is convenient for the liquid flowing out of the impeller to cut into the guide vane ring.

[0034] As an optional implementation manner of the embodiment of the present invention, refer to Figure 1 , Figure 3 , guide vane ring blades 5 are formed on the outer side surface of the leading guide vane ring 2, and the guide vane ring blades 5 are evenly spaced along the circumferential direction of the leading guide vane ring 2, and liquid flow channels are formed between two adjacent guide vane ring blades 5; guide vane ring blades 5 are formed on the outer side surface of the last-stage guide vane ring 4, and the guide vane ring blades 5 are evenly spaced along the circumferential direction of the last-stage guide vane ring 4, and liquid flow channels are formed between two adjacent guide vane ring blades 5.

[0035] As an optional implementation manner of the embodiment of the present invention, the first outer contour 51 is the convex profile of the guide vane ring blade 5, and the second outer contour 52 is the concave profile of the guide vane ring blade 5; one side of the first outer contour 51 and the second outer contour 52 close to the blade inlet angle are connected; the guide vane ring blade 5 further includes a third outer contour 53, the third outer contour 53 is far from the connection end of the first outer contour 51 and the second outer contour 52, the third outer contour 53 of the front guide vane ring 2 is flush with one end face of the front guide vane ring 2, and the third outer contour 53 of the last stage guide vane ring 4 is flush with one end face of the last stage guide vane ring 4; both ends of the third outer contour 53 are respectively connected to the first outer contour 51 and the second outer contour 52, and there is a smooth transition between the third outer contour 53 and the second termination arc 522. After passing through the front guide vane ring 2 or the last stage guide vane ring 4, the liquid flow direction changes from mainly circumferential to mainly "axial". Also, because the flow channel in the front guide vane ring 2 is divergent (limited by the shape of the guide vane ring blade 5), the liquid flow velocity gradually decreases when the liquid flows through, and part of the kinetic energy is converted into pressure energy during this flow process.

[0036] The above setting of the shape of the guide vane ring blade 5 also minimizes the liquid flow loss as much as possible; in addition, referring to Figures 1-4 , the guide vane ring blade 5 is narrower near the inlet end to facilitate the liquid to cut into the guide vane ring and avoid too small a liquid inlet of the guide vane ring; the width of the guide vane ring blade 5 is larger near the outlet end to increase the strength of the guide vane ring blade 5.

[0037] As an optional implementation manner of the embodiment of the present invention, the height of the last stage guide vane ring 4 in the axial direction is greater than the height of the front guide vane ring 2 in the axial direction; the height range of the front guide vane ring 2 can be 30 cm to 35 cm, and the height of the front guide vane ring 2 can be 32 cm; the height range of the last stage guide vane ring 4 can be 55 cm to 60 cm, and the height of the last stage guide vane ring 4 can be 57 cm.

[0038] As an optional implementation manner of the embodiment of the present invention, the number of the last-stage guide vane rings 4 is one, and the sum of the number of the last-stage guide vane rings 4 and the number of the front guide vane rings 2 is equal to the number of the impellers in the submersible pump; the impellers are distributed at intervals between the last-stage guide vane rings 4 and the front guide vane rings 2. The impeller closest to the inducer 12 is the first one, the front guide vane ring 2 is arranged between two impellers, and the last one is the last-stage guide vane ring 4. The liquid flowing out of the impeller can flow to the adjacent guide vane ring; the front guide vane ring 2 and the last-stage guide vane ring 4 are respectively sleeved on the inner guide shells of the corresponding submersible pumps. The cryogenic liquid introduced by the inducer 12 enters the (primary) impeller, and after the energy of the (primary) impeller is increased, it enters the front guide vane ring 2. In this process, the motor drives the impeller on the rotor shaft to rotate at a high speed, converting its mechanical energy into the mechanical energy of the liquid (the mechanical energy of the liquid includes pressure energy and kinetic energy). After passing through the front guide vane ring 2, the flow direction of the liquid changes from mainly the circumferential direction to mainly the "axial" direction. By analogy, the liquid enters the process of pressurizing and energy increasing at the lower stage (increasing the liquid pressure and improving the mechanical energy of the liquid) in the same principle, that is, it enters the next impeller, the next front guide vane ring 2... and finally flows to the last-stage guide vane ring 4, and flows from the last-stage guide vane ring 4 to the built-in flow channel between the motor 10 and the motor housing 11.

[0039] As an optional implementation manner of the embodiment of the present invention, along the direction of the liquid passing through the submersible pump, the number of the blades of the impeller arranged in front of the last-stage guide vane ring 4 and adjacent to the last-stage guide vane ring 4 is not equal to the number of the guide vane blades 5 on the last-stage guide vane ring 4; along the direction of the liquid passing through the submersible pump, the number of the blades of the impeller arranged in front of the front guide vane ring 2 and adjacent to the front guide vane ring 2 is not equal to the number of the guide vane blades 5 on the front guide vane ring 2. The number of the impellers can be two, namely the front impeller 1 and the last-stage impeller 3. The number of the front guide vane rings 2 can be one. The number of the guide vane blades 5 on the front guide vane ring 2 is different from the number of the impeller blades on the front impeller 1. The number of the guide vane blades 5 on the front guide vane ring 2 can be 9, and the number of the impeller blades on the front impeller 1 can be 8; the number of the guide vane blades 5 on the last-stage guide vane ring 4 is different from the number of the impeller blades on the last-stage impeller 3. The number of the guide vane blades 5 on the last-stage guide vane ring 4 can also be 9, and the number of the impeller blades on the last-stage impeller 3 can be 8. Suppose that if the number of the guide vane blades 5 on the front guide vane ring 2 is the same as the number of the impeller blades on the front impeller 1, and the blades are usually evenly distributed at intervals, then at a certain moment, the liquid outlet on the front impeller 1 may respectively correspond to the end parts of the guide vane blades 5 on the front guide vane ring 2 (that is, corresponding to Figure 1 a slender section on the inlet side of the middle guide vane blade 5), which affects the liquid flowing out of the front impeller 1 from flowing into the front guide vane ring 2, resulting in large liquid energy loss and may also cause relatively large vibration.

[0040] As an optional implementation manner of the embodiment of the present invention, a liquid inlet filter body 13 is installed on the front outer guide shell 9 of the cryogenic submersible pump. Filter holes are formed in the bottom and side walls of the liquid inlet filter body 13. The liquid inlet filter body 13 is composed of a filter screen and a support, and is laterally fixed to the front outer guide shell 9 by bolts. The liquid inlet filter body 13 adopts a flared form. At its bottom end, a round-hole type filter screen support body and a filter screen are used. The round-hole type filter screen support structure will not cause the filter assembly to become loose due to the suction force and vibration during the operation of the pump. In addition, in the prior art, the liquid inlet filter body only has a filter screen at the bottom of the screen body. Therefore, impurities deposited at the bottom of the pump pool are likely to block the liquid inlet filter body, resulting in its damage or poor circulation. However, for the cryogenic submersible pump provided by the present invention, the side wall and bottom of the liquid inlet filter body 13 both adopt a filter screen structure, which not only increases the liquid inlet area but also avoids the blockage of the liquid inlet filter body 13 as much as possible.

[0041] As an optional implementation manner of the embodiment of the present invention, the motor 10 of the cryogenic submersible pump is a cryogenic permanent magnet motor; the stator of the motor 10 is a permanent magnet stator. The cryogenic permanent magnet motor has small heat generation, low loss, and high efficiency; compared with the three-phase asynchronous motor with the same power in the original technology, the volume of this permanent magnet motor is small, and the reduction of the motor volume enables the outer shape of the pump body to be unrestricted by the size of the motor.

[0042] Embodiment 1:

[0043] A cryogenic submersible pump provided with a guide vane ring inside includes a front impeller 1, a front inner guide shell 6, a last-stage impeller 3, and a last-stage inner guide shell 7; a front guide vane ring 2 is sleeved outside the front inner guide shell 6 and the two are detachably connected; a front outer guide shell 9 is sleeved outside the front impeller 1 and the front guide vane ring 2, and a last-stage outer guide shell 8 is arranged above the front outer guide shell 9; there is a liquid flow channel between the front inner guide shell 6 and the last-stage outer guide shell 8, and the liquid coming out of the front guide vane ring 2 can flow into the last-stage impeller 3 through the liquid flow channel; a last-stage guide vane ring 4 is sleeved outside the last-stage inner guide shell 7, and the last-stage impeller 3 and the last-stage guide vane ring 4 are located inside the last-stage outer guide shell 8; the blade outlet angle of the front guide vane ring 2 is smaller than the blade outlet angle of the last-stage guide vane ring 4; the blade outlet angle range of the last-stage guide vane ring 4 is preferably between 70° and 80°; the blade outlet angle range of the front guide vane ring 2 is preferably between 40° and 50°, and the blade inlet angle range of the front guide vane ring 2 is between 2° and 5°; the blade inlet angle range of the last-stage guide vane ring 4 is between 2° and 5°.

[0044] The specific structure of the cryogenic submersible pump can be as follows: The cryogenic submersible pump further includes an upper motor cover 14, a motor housing 11, a last-stage outer guide shell 8, and a front outer guide shell 9; a liquid inlet filter body 13 is installed at the bottom end of the front outer guide shell 9; the outer top end of the motor housing 11 is fixedly provided with an upper motor cover 14, the inner top end is fixedly provided with a bearing seat, the bottom end is fixedly provided with a last-stage outer guide shell 8, and the bottom end of the last-stage outer guide shell 8 is fixedly connected to the front outer guide shell 9;

[0045] Inside the motor housing 11, a motor 10 is fixedly provided; an exhaust valve 15 is provided at the top of the motor 10 and the exhaust valve 15 is located inside the upper end cover 14 of the motor; the motor 10 includes a motor stator and a motor rotor, and a final-stage inner guide housing 7 is provided at the bottom end of the motor 10; a plurality of flow channels are provided between the motor 10 and the motor housing 11, the motor rotor is located inside the motor stator, and a connecting shaft rod 16 is provided. Above the shaft rod 16, a bearing is connected, and below the shaft rod 16, a bearing, a final-stage impeller 3, a front impeller 1, and an inducer 12 are connected.

[0046] As described above, it is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A cryogenic submersible pump with a guide vane ring provided inside, Characterized in that, It includes a last-stage guide vane ring (4) and a front guide vane ring (2), wherein, The last-stage guide vane ring (4) is arranged on one side close to the rotor of the submersible pump motor, and the number of the front guide vane rings (2) is at least one, and all the front guide vane rings (2) and the last-stage guide vane ring (4) are arranged in sequence along the axis of the submersible pump; There are guide vane ring blades (5) on both the front guide vane ring (2) and the last-stage guide vane ring (4); The guide vane ring blade (5) includes a first outer contour (51) and a second outer contour (52), the first outer contour (51) is the suction surface, and the second outer contour (52) is the pressure surface; The first outer contour (51) includes a first starting arc (511) and a first ending arc (512), and a blade inlet angle is formed between the first starting arc (511) and the horizontal section plane; The second outer contour (52) includes a second starting arc (521) and a second ending arc (522), and a blade outlet angle is formed between the second ending arc (522) and the horizontal section plane; The blade inlet angle of each guide vane ring blade (5) is smaller than its own blade outlet angle; The blade outlet angle of the front guide vane ring (2) is smaller than the blade outlet angle of the last-stage guide vane ring (4).

2. The cryogenic submersible pump with a guide vane ring provided inside according to claim 1, Characterized in that, The range of the blade outlet angle of the last-stage guide vane ring (4) is between 70° and 80°; the range of the blade outlet angle of the front guide vane ring (2) is between 40° and 50°.

3. The cryogenic submersible pump with a guide vane ring provided inside according to claim 1, Characterized in that, The range of the blade inlet angle of the front guide vane ring (2) is between 2° and 5°; the range of the blade inlet angle of the last-stage guide vane ring (4) is between 2° and 5°.

4. The cryogenic submersible pump with a guide vane ring provided inside according to claim 1, Characterized in that, The guide vane ring blades (5) are formed on the outer side surface of the front guide vane ring (2) and are evenly spaced along the circumferential direction of the front guide vane ring (2); The guide vane ring blades (5) are formed on the outer side surface of the last-stage guide vane ring (4) and are evenly spaced along the circumferential direction of the last-stage guide vane ring (4).

5. The cryogenic submersible pump with a guide vane ring provided inside according to any one of claims 1-4, Characterized in that, The first outer contour (51) is the convex profile line of the guide vane ring blade (5), and the second outer contour (52) is the concave profile line of the guide vane ring blade (5); The first outer contour (51) and the second outer contour (52) are connected to each other on the side close to the blade inlet angle; The guide vane ring blade (5) further includes a third outer contour (53), which is away from the connection end of the first outer contour (51) and the second outer contour (52). The third outer contour (53) of the front guide vane ring (2) is flush with one end face of the front guide vane ring (2), and the third outer contour (53) of the last stage guide vane ring (4) is flush with one end face of the last stage guide vane ring (4). Both ends of the third outer contour (53) are respectively connected to the first outer contour (51) and the second outer contour (52), and there is a smooth transition between the third outer contour (53) and the second termination arc (522).

6. The cryogenic submersible pump with a guide vane ring according to claim 5, characterized in that the height of the last stage guide vane ring (4) in the axial direction is greater than the height of the front guide vane ring (2) in the axial direction.

7. The cryogenic submersible pump with a guide vane ring according to claim 6, characterized in that the height range of the front guide vane ring (2) is 30 cm to 35 cm; the height range of the last stage guide vane ring (4) is 55 cm to 60 cm.

8. The cryogenic submersible pump with a guide vane ring according to any one of claims 1-4, characterized in that along the direction of the liquid passing through the submersible pump, the number of blades of the impeller arranged in front of the last stage guide vane ring (4) and adjacent to the last stage guide vane ring (4) is not equal to the number of guide vane ring blades (5) on the last stage guide vane ring (4); along the direction of the liquid passing through the submersible pump, the number of blades of the impeller arranged in front of the front guide vane ring (2) and adjacent to the front guide vane ring (2) is not equal to the number of guide vane ring blades (5) on the front guide vane ring (2).

9. The cryogenic submersible pump with a guide vane ring according to any one of claims 1-4, characterized in that the number of the last stage guide vane rings (4) is one, and the sum of the number of the last stage guide vane rings (4) and the number of the front guide vane rings (2) is equal to the number of impellers in the submersible pump; the impellers are distributed at intervals between the last stage guide vane ring (4) and the front guide vane ring (2), and the liquid coming out of the inducer (12) of the submersible pump can first flow to the impeller, and the liquid coming out of the impeller can flow to the guide vane ring adjacent to the impeller; the front guide vane ring (2) and the last stage guide vane ring (4) are respectively sleeved on the inner guide shell of the corresponding submersible pump.

10. The cryogenic submersible pump with a guide vane ring according to any one of claims 1-4, characterized in that a liquid inlet filter body (13) is installed on the front outer guide shell (9) of the cryogenic submersible pump, and filter holes are all opened at the bottom and side walls of the liquid inlet filter body (13).

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