High-pressure shielding type multi-stage pump

Abstract

The utility model relates to the field of pumps, in particular to a high-pressure shielding type multistage pump which comprises a conveying section and a power section which are sequentially arranged from bottom to top in the vertical direction, the conveying section comprises a conveying sleeve with an inner cavity and an outer cavity, and a hydraulic assembly is arranged in an inner cavity of the conveying sleeve. An outer cavity of the conveying sleeve forms a conveying channel used for conveying media, the media enter the hydraulic assembly from a pump inlet of the conveying section through the conveying channel from bottom to top, then pass through the hydraulic assembly from top to bottom and are discharged through a pump outlet of the conveying section, and a driving shaft in the power section provides power for the hydraulic assembly. The axial force of the shielding type multi-stage pump is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the field of pumps, in particular to a high-pressure shielded multi-stage pump. Background Art

[0002] The shielded multistage pump is an important equipment in the fields of chemical, petrochemical, chemical fiber, pharmaceutical, refrigeration and nuclear power. It is a combination of centrifugal pump and shielded motor. The rotor and impeller of the shielded multistage pump are fixed on the same shaft. The shielding sleeve is used to separate the rotor and stator. The rotor rotates in the medium being transported, and its power is transferred to the rotor through the stator magnetic field, and then to the impeller of the shielded pump.

[0003] As described in the publication number "CN116221136A", the existing shielded multi-stage pump is generally suitable for large flow and high head conditions. The axial force of the pump is large under operating conditions. When it is arranged vertically, the axial force also includes the weight of the rotor assembly and several impellers. During operation, excessive axial force will greatly increase the wear of the bearings in the pump body, resulting in reduced performance and shortened life of the pump. Therefore, it is urgent to solve this problem. Utility Model Content

[0004] In order to avoid and overcome the technical problems existing in the prior art, the utility model provides a high-pressure shielded multistage pump. The utility model greatly reduces the axial force of the shielded multistage pump.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A high-pressure shielded multi-stage pump comprises a conveying section and a power section which are arranged in sequence from bottom to top along a vertical direction. The conveying section comprises a conveying sleeve having an inner and outer cavity. A hydraulic component is arranged in the inner cavity of the conveying sleeve. The outer cavity of the conveying sleeve constitutes a conveying channel for conveying a medium. The medium enters the hydraulic component after passing through the conveying channel from bottom to top from the pump inlet of the conveying section, and then passes through the hydraulic component from top to bottom and is discharged through the pump outlet of the conveying section. A driving shaft in the power section provides power for the hydraulic component. Rectifier plates which are plugged and fixed are evenly installed along the circumferential direction at the pump outlet. The plate surfaces on both sides of the rectifier plates are straight plates and inclined plates respectively, and the plate surfaces of the straight plates are arranged radially along the pump outlet.

[0007] As a further solution of the utility model: the hydraulic component includes impellers evenly spaced along the axial direction on the driving shaft, and each impeller conveys the medium from top to bottom; the inner cavity of the conveying sleeve is also axially arranged with guide vanes located on the outer ring of the impeller, and the guide vanes and each impeller are enclosed to form a flow channel for conveying the medium; the impeller rear cover plate of each impeller is provided with a reflux inlet at the medium outlet, and the impeller rear cover plate of each impeller is provided with a reflux outlet at the medium inlet, and a throttling ring is installed on the rear cover plate of each impeller, and a sealing ring corresponding to the position of each throttling ring is installed on the guide vane, and a balancing gap is provided between the sealing ring and the throttling ring for the medium to pass through; a part of the medium discharged from the impeller passes through the reflux inlet, the balancing gap and the reflux outlet in turn and then flows back to the impeller inlet to form a reflux channel.

[0008] As a further solution of the utility model: the flow area F of the balancing gap m for:

[0009]

[0010] Among them, A represents the axial force that the pump body needs to balance;

[0011] D m The drag coefficient representing the balance gap;

[0012] g represents the acceleration due to gravity;

[0013] q represents the leakage of the medium through the return channel;

[0014] ρ represents the medium density;

[0015] R m represents the radius of the sealing ring,

[0016] R h Indicates the effective radius of the impeller hub.

[0017] As a further solution of the utility model: two groups of parallel limit plates are provided on the guide vane, the sealing ring is clamped and fixed by the two limit plates, the gap width between the inner circle of the limit plate and the throttling ring is greater than the width of the balance gap; each impeller is coaxially fixed on the drive shaft through a threaded fixing cap.

[0018] As a further solution of the utility model: the guide vanes are arranged in multiple sections, the uppermost guide vanes are pressed and fixed by the inlet pressure cover; the lowermost guide vanes are pressed on the pump body mouth ring, and a sealing ring is arranged between the pump body mouth ring and the lowermost guide vanes; the gap between the outer ring of the guide vanes and the inner ring of the conveying sleeve is filled with the conveying medium.

[0019] As a further solution of the utility model: the power section includes a stator assembly and a rotor assembly arranged in the motor housing for electromagnetic induction cooperation, the rotor assembly is located at the inner ring of the stator assembly and is coaxially fixed with the drive shaft; a first bearing seat and a second bearing seat are provided at both ends of the power section, and the conveying section and the power section are separated by the second bearing seat; a first locating bearing and a second locating bearing are respectively provided in the first bearing seat and the second bearing seat, and the first locating bearing and the second locating bearing are rotationally cooperated with the drive shaft.

[0020] As a further solution of the utility model: the outer ring of the rotor assembly is provided with a rotor shielding sleeve, the inner ring of the stator assembly is provided with a stator shielding sleeve, and an annular cooling gap is provided between the stator shielding sleeve and the rotor shielding sleeve.

[0021] As a further solution of the utility model: a first guide hole and a second guide hole for medium to pass through are respectively provided on the first bearing seat and the second bearing seat; the end of the drive shaft extends to the outlet of the hydraulic component, and an axial hole is axially provided in the drive shaft, and a part of the medium at the outlet of the hydraulic component passes through the axial hole from bottom to top and enters the power section, and passes through the first guide hole, the cooling gap and the second guide hole in sequence, and arrives at the inlet of the hydraulic component.

[0022] As a further solution of the utility model: the shaft hole is a two-stage stepped hole that is wide at the top and narrow at the bottom, the large diameter section of the shaft hole is located in the power section, and the small diameter section of the shaft hole is located in the conveying section.

[0023] As a further solution of the utility model: the angle between the inclined plate and the straight plate of the rectifier plate is 27.3° to 36.2°.

[0024] Compared with the prior art, the beneficial effects of the utility model are:

[0025] 1. The utility model changes the direction of the impeller inlet in the shielded multi-stage pump so that the impeller inlet faces the stator assembly. The conveyed medium enters the hydraulic assembly from bottom to top through the conveying channel from the pump inlet of the conveying section, passes through the hydraulic assembly from top to bottom, and is discharged from the pump outlet of the conveying section. By changing the flow direction, the high-pressure area of ​​the impeller group is at the bottom and the low-pressure area is at the top. The pressure difference generates an upward lifting force on the hydraulic assembly, which is offset by the self-gravity of the hydraulic assembly, greatly reducing the axial force of the pump, avoiding the bearing from being affected by excessive axial force and causing wear, and increasing the service life of the pump body.

[0026] 2. The utility model forms a reflux channel on the impeller rear cover plate by arranging a throttling ring on the impeller. The reflux channel can introduce the pressure of the impeller suction port into the throttling ring. Through the cooperation of the throttling ring and the reflux channel, the area of ​​the impeller rear cover plate inside the throttling ring can be kept at low pressure, and the area outside the impeller throttling ring is high pressure, thereby balancing the axial force. According to the value of the axial force to be balanced, the most suitable flow area of ​​the balancing gap is calculated, thereby selecting the most suitable size of the sealing ring.

[0027] 3. The utility model forms a sliding friction pair by cooperating the positioning bearing and the thrust bearing in the two bearing seats, so that when the multi-stage pump is in operation, the thrust bearing bears the axial force; during the operation of the pump, holes are opened on the drive shaft and the bearing seat to inhale the medium from the bottom to the top from the outlet of the hydraulic component, and pass through the gap between the stator shielding sleeve and the rotor shielding sleeve, thereby achieving a cooling effect on the power section.

[0028] 4. The arrangement of the rectifying plate at the pump outlet of the utility model makes the outlet medium flow more uniform and avoids turbulence. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the utility model.

[0030] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0031] In the figure:

[0032] 1. Conveying section;

[0033] 11. hydraulic assembly; 111. impeller; 1111. return outlet; 1112. threaded fixing cap;

[0034] 112, guide vane; 1121, limit plate; 1122, sealing ring; 1123, return inlet;

[0035] 113. Throttle ring;

[0036] 12. Delivery sleeve; 13. Delivery channel; 14. Pump inlet;

[0037] 15. Pump outlet; 16. Hydraulic component inlet; 17. Hydraulic component outlet;

[0038] 2. Power section; 21. Stator assembly; 211. Stator shielding sleeve;

[0039] 22. rotor assembly; 221. rotor shielding sleeve;

[0040] 23. driving shaft; 231. shaft hole;

[0041] 24. First bearing seat; 25. Second bearing seat;

[0042] 241. a first positioning bearing; 242. a first thrust bearing; 243. a first guide hole;

[0043] 251. Second positioning bearing; 252. Second thrust bearing; 253. Second guide hole. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0045] See also Figures 1-2 In an embodiment of the utility model, a high-pressure shielded multistage pump includes a conveying section 1 and a power section 2 arranged in sequence from bottom to top along the vertical direction, and the power section 2 provides a power source for the drive shaft 23. The power section 2 includes a stator assembly 21 and a rotor assembly 22 arranged in the motor housing for electromagnetic induction matching, and the rotor assembly 22 is arranged in the inner ring of the stator assembly 21 and is coaxially fixed with the drive shaft 23. The upper and lower ends of the power section 2 are respectively provided with a first bearing seat 24 and a second bearing seat 25, and the first bearing seat 24 and the second bearing seat 25 are respectively provided with a first locating bearing 241 and a second locating bearing 251, and the first locating bearing 241 and the second locating bearing 251 are rotatably matched with the drive shaft 23.

[0046] The drive shaft 23 has an upper shoulder and a lower shoulder. The first thrust bearing 242 is in abutment with the upper shoulder of the drive shaft 23, and the second thrust bearing 252 is in abutment with the lower shoulder of the drive shaft 23. From top to bottom, the first locating bearing 241, the first thrust bearing 242 and the upper shoulder are arranged in sequence, and the lower shoulder, the second thrust bearing 252 and the second locating bearing 251 are arranged in sequence. The first locating bearing 241 cooperates with the first thrust bearing 242 to form a sliding friction pair, and the second locating bearing 251 cooperates with the second thrust bearing 252 to form a sliding friction pair. When the multi-stage pump is running, due to the action of the axial force, the rotor assembly 22 moves axially, and the axial force is borne by two sets of thrust bearings to avoid damage to the parts inside the pump.

[0047] The inner ring of the stator assembly 21 is provided with a stator shielding sleeve 211. The two ends of the stator shielding sleeve 211 are welded and sealed with the flange of the stator assembly to protect the stator assembly 21 and prevent the medium from contacting the stator assembly 21 and short-circuiting and burning the machine. In addition, the stator shielding sleeve 211 is generally made of a non-magnetic and non-magnetic metal thin round tube that can withstand high temperature and high pressure.

[0048] The outer ring of the rotor assembly 22 is provided with a rotor shielding sleeve 221, which rotates synchronously with the rotor, and both ends of the rotor shielding sleeve 221 are also sealed by flanges and other components. There is an annular cooling gap between the stator shielding sleeve 211 and the rotor shielding sleeve 221, which can allow the medium to pass through.

[0049] In order to achieve a cooling effect, the drive shaft 23 is set as a hollow shaft, and an axial hole 231 that penetrates the drive shaft 23 is opened at the axis of the drive shaft 23. One end of the axial hole 231 is connected to the hydraulic component outlet 17, and the other end of the axial hole 231 is connected to the first guide hole 243 on the first bearing seat 24. The second bearing seat 25 has a partition effect on the conveying section 1 and the power section 2. The conveying section 1 only exchanges medium with the power section 2 through the second guide hole 253 on the second bearing seat 25. Under the action of the pressure difference, the medium at the hydraulic component outlet 17 passes through the axial hole 231 from bottom to top, reaches the cavity of the power section 2, and passes through the first guide hole 243, the cooling gap between the two shielding sleeves, and the second guide hole 253 in turn, and then returns to the conveying section 1 and reaches the hydraulic component inlet 16.

[0050] The shaft hole 231 of the driving shaft 23 is a two-stage stepped hole that is wide at the top and narrow at the bottom. The large diameter section of the shaft hole 231 corresponds to the position of the power section 2 , and the small diameter section of the shaft hole 231 corresponds to the position of the conveying section 1 .

[0051] The pump inlet 14 and the pump outlet 15 of the conveying section 1 are located at the bottom, and the pump inlet 14 and the pump outlet 15 are located at the same height. The conveying section 1 includes a conveying sleeve 12 having an inner and outer cavity. The outer cavity of the conveying sleeve 12 is connected to the pump inlet 14, thereby forming a conveying channel 13. The inner cavity of the conveying sleeve 12 is used to install the hydraulic component 11. The top of the inner cavity of the conveying sleeve 12 constitutes the hydraulic component inlet 16, and the bottom of the inner cavity of the conveying sleeve 12 constitutes the hydraulic component outlet 17. The hydraulic component outlet 17 is connected to the pump outlet 15, and the end of the drive shaft 23 extends to the hydraulic component outlet 17.

[0052] There is a cavity between the hydraulic component 11 and the inner wall of the conveying sleeve 12, and the medium can enter the inner cavity of the conveying sleeve 12 from the hydraulic component outlet 17 to fill the space between the hydraulic component 11 and the conveying sleeve 12. After the medium enters the hydraulic component 11 from the pump inlet 14 of the conveying section 1 through the conveying channel 13 from bottom to top, it passes through the hydraulic component 11 from top to bottom and is discharged through the pump outlet 15 of the conveying section 1. Plug-in fixed rectifier plates are evenly installed along the circumference at the pump outlet 15, and are detachably fixed to facilitate the replacement of rectifier plates of different sizes. The plate surfaces on both sides of the rectifier plate are straight plates and inclined plates respectively. The plate surfaces of the straight plates are arranged radially along the pump outlet 15, and the angle between the inclined plate and the straight plate of the rectifier plate is 27.3° to 36.2°, preferably 32.5°.

[0053] The hydraulic assembly 11 includes impellers 111 evenly arranged along the shaft of the driving shaft 23 . The inlet of each impeller 111 is at the top and the outlet is at the bottom. Each impeller 111 is coaxially fixed to the driving shaft 23 through a threaded fixing cap 1112 .

[0054] Multiple groups of stacked guide vanes 112 are arranged in the inner cavity of the conveying sleeve 12. The uppermost guide vanes 112 are pressed and fixed by the inlet gland of the pump body, and a sealing ring is arranged between the inlet gland and the uppermost guide vanes 112; the lowermost guide vanes 112 are pressed against the pump body mouth ring, and a sealing ring is arranged between the pump body mouth ring and the lowermost guide vanes 112. The top of the inlet gland is fixed with the boss on the second bearing seat 25. The bosses on the second bearing seat 25 are preferably four, and a flow passage is formed between adjacent bosses.

[0055] The number of the guide vanes 112 corresponds to that of the impellers 111 , and they are arranged on the outer ring of each impeller 111 . The guide vanes 112 and each impeller enclose a flow channel for conveying a medium.

[0056] The impeller rear cover of each impeller 111 is provided with a reflux inlet 1123 at the medium outlet, and the impeller rear cover of each impeller 111 is provided with a reflux outlet 1111 at the medium inlet. A throttling ring 113 is installed on the rear cover of each impeller 111, and a sealing ring 1122 corresponding to the position of each throttling ring 113 is installed on the guide vane 112. There is a balance gap between the sealing ring 1122 and the throttling ring 113 for the medium to pass through. The existence of the balance gap allows the sealing ring 1122 to move in a small range along the radial direction of the drive shaft 23; a part of the medium discharged from the impeller 111 passes through the reflux inlet 1123, the balance gap and the reflux outlet 1111 in turn and then flows back to the inlet of the impeller 111 to form a reflux channel. Two sets of parallel limit plates 1121 are provided on the guide vane 112 , and the sealing ring 1122 is clamped and fixed by the two limit plates 1121 . The width of the gap between the inner ring of the limit plate 1121 and the throttling ring 113 is greater than the width of the balance gap.

[0057] Balance gap flow area F m for:

[0058]

[0059] Among them, A represents the axial force that the pump body needs to balance;

[0060] D m The drag coefficient representing the balance gap;

[0061] g represents the acceleration due to gravity;

[0062] q represents the leakage of the medium through the return channel;

[0063] ρ represents the medium density;

[0064] R m represents the radius of the sealing ring 1122,

[0065] R h represents the effective radius of the hub of the impeller 111 .

[0066] According to the axial force that needs to be reduced in the pump body, the flow area of ​​the balance gap can be calculated, so as to select the most suitable size of sealing ring.

[0067] The guide vane 112 is also provided with a sealing ring corresponding to the position of the impeller front cover plate, which is also clamped and fixed by a limit plate. The sealing ring cooperates with the impeller front cover plate to prevent the medium from leaking at the impeller front cover plate. The sealing ring is preferably made of a plastic material with good lubricity.

[0068] The throttle ring 113 and the impeller rear cover plate are preferably arranged in a split structure, so that they can be manufactured by stamping a thin plate and then welded into one body, which is simple to manufacture, has high production efficiency and reduces manufacturing costs.

[0069] The limit plate 1121 and the guide vane 112 are welded into one body, which can also be manufactured by stamping a thin plate and then welding them into one body, which is simple to process, has high production efficiency and reduces production costs.

[0070] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0071] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

Claims

1. A high-pressure canned multistage pump, characterized in that: The invention comprises a conveying section (1) and a power section (2) which are arranged in sequence from bottom to top in a vertical direction. The conveying section (1) comprises a conveying sleeve (12) having an inner and outer cavity. A hydraulic component (11) is arranged in the inner cavity of the conveying sleeve (12). The outer cavity of the conveying sleeve (12) constitutes a conveying channel (13) for conveying a medium. The medium passes through the conveying channel (13) from bottom to top from a pump inlet (14) of the conveying section (1) and then enters the hydraulic component (11). Then, the medium passes through the hydraulic component (11) from top to bottom and is discharged through a pump outlet (15) of the conveying section (1). A driving shaft (23) in the power section (2) provides power for the hydraulic component (11). Rectifier plates which are plugged and fixed are evenly installed along the circumference at the pump outlet (15). The plate surfaces on both sides of the rectifier plates are straight plates and inclined plates respectively. The plate surfaces of the straight plates are arranged along the radial direction of the pump outlet.

2. A high-pressure shielded multistage pump according to claim 1, characterized in that: The hydraulic assembly (11) comprises impellers (111) arranged at even intervals along the axial direction on a driving shaft (23), and each impeller (111) conveys a medium from top to bottom; the inner cavity of the conveying sleeve (12) is also provided with guide vanes (112) located on the outer ring of the impeller (111) along the axial direction, and the guide vanes (112) and each impeller (111) are enclosed to form a flow channel for conveying the medium; the impeller rear cover plate of each impeller (111) is provided with a reflux inlet (1123) at the medium outlet, and the impeller rear cover plate of each impeller (111) is provided with a reflux inlet (1123) at the medium inlet. A reflux outlet (1111) is provided, a throttling ring (113) is installed on the rear cover plate of each impeller (111), a sealing ring (1122) corresponding to the position of each throttling ring (113) is installed on the guide vane (112), and a balancing gap is provided between the sealing ring (1122) and the throttling ring (113) for medium to pass through; a portion of the medium discharged from the impeller (111) passes through the reflux inlet (1123), the balancing gap and the reflux outlet (1111) in sequence and then flows back to the inlet of the impeller (111) to form a reflux channel.

3. A high-pressure shielded multistage pump according to claim 2, characterized in that: Balance gap flow area F m for: Among them, A represents the axial force that the pump body needs to balance; D m The drag coefficient representing the balance gap; g represents the acceleration due to gravity; q represents the leakage of the medium through the return channel; ρ represents the medium density; R m represents the radius of the sealing ring (1122), R h represents the effective radius of the hub of the impeller (111).

4. A high-pressure shielded multistage pump according to claim 2, characterized in that: The guide vane (112) is provided with two groups of limit plates (1121) arranged in parallel, the sealing ring (1122) is clamped and fixed by the two limit plates (1121), and the width of the gap between the inner ring of the limit plate (1121) and the throttling ring (113) is greater than the width of the balance gap; each impeller (111) is coaxially fixed on the driving shaft (23) through a threaded fixing cap (1112).

5. A high-pressure canned multistage pump according to any one of claims 2 to 4, characterized in that: The guide vanes (112) are arranged in multiple stages. The uppermost guide vanes (112) are pressed and fixed by an inlet gland. The lowermost guide vanes (112) are pressed against a pump body mouth ring. A sealing ring is arranged between the pump body mouth ring and the lowermost guide vanes (112). The gap between the outer ring of the guide vanes (112) and the inner ring of the conveying sleeve (12) is filled with conveying medium.

6. A high-pressure canned multistage pump according to any one of claims 1 to 4, characterized in that: The power section (2) comprises a stator assembly (21) and a rotor assembly (22) arranged in an electromagnetic induction match in a motor housing, wherein the rotor assembly (22) is located in the inner ring of the stator assembly (21) and is coaxially fixed with the drive shaft (23); a first bearing seat (24) and a second bearing seat (25) are arranged at both ends of the power section (2), and the conveying section (1) and the power section (2) are separated by the second bearing seat (25); a first locating bearing (241) and a second locating bearing (251) are arranged in the first bearing seat (24) and the second bearing seat (25), respectively, and the first locating bearing (241) and the second locating bearing (251) are rotatably matched with the drive shaft (23).

7. A high-pressure canned multistage pump according to claim 6, characterized in that: The outer ring of the rotor assembly (22) is provided with a rotor shielding sleeve (221), the inner ring of the stator assembly (21) is provided with a stator shielding sleeve (211), and an annular cooling gap exists between the stator shielding sleeve (211) and the rotor shielding sleeve (221).

8. A high-pressure canned multistage pump according to claim 7, characterized in that: A first guide hole (243) and a second guide hole (253) for medium to pass through are respectively provided on the first bearing seat (24) and the second bearing seat (25); the end of the drive shaft (23) extends to the hydraulic component outlet (17); an axial hole (231) is axially provided in the drive shaft (23); a portion of the medium at the hydraulic component outlet (17) passes through the axial hole (231) from bottom to top and enters the power section (2), and then passes through the first guide hole (243), the cooling gap and the second guide hole (253) in sequence and arrives at the hydraulic component inlet (16).

9. A high-pressure canned multistage pump according to claim 8, characterized in that: The shaft hole (231) is a two-stage stepped hole that is wider at the top and narrower at the bottom. The large diameter section of the shaft hole (231) is located in the power section (2), and the small diameter section of the shaft hole (231) is located in the conveying section (1).

10. A high-pressure canned multistage pump according to claim 1, characterized in that: The angle between the inclined plate and the straight plate of the rectifier plate is 27.3° to 36.2°.

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