Axial force balance control structure

Abstract

The utility model relates to the technical field of axial force control, in particular to an axial force balance control structure, which is characterized in that a compressor comprises an impeller, and the impeller is provided with an air inlet end positioned in an air inlet area, an exhaust end positioned in an exhaust area and a back part positioned in a back area of the impeller; the axial force balance control structure comprises a first sealing ring which is arranged on the air inlet end in a sleeving mode and serves as a component used for preventing high-pressure air exhausted from the air exhaust end from flowing to the air inlet end; the second sealing ring is arranged on the back part in a sleeving manner and is used as a component for preventing the high-pressure gas exhausted from the exhaust end from flowing to the gas inlet end; the size of an annular structure defined by the inner wall of the first sealing ring is larger than that of an annular structure defined by the inner wall of the second sealing ring. By means of the arrangement, the leakage amount can be reduced when high-pressure gas leaks due to gradual abrasion of the second sealing ring, and therefore the overall efficiency of the compressor is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to axial force control technical field, concretely relates to a kind of axial force balance control structure. BACKGROUND

[0002] Some compressors of the prior art accelerate and compress gas by rotating impellers. When operating under different conditions, due to the changes in gas pressure and flow rate, an axial force parallel to the axis of the compressor is generated. The specific direction and magnitude of the axial force depend on the specific design and operating conditions of the compressor. The axial force attempts to push the rotor towards one end of the compressor, thus generating pressure on the bearing that supports the rotor. If the bearing bears excessive load, it may be subject to wear, overheating, or even damage.

[0003] After being compressed, the gas forms high-pressure gas. The high-pressure gas tends to flow from the high-pressure area (the area around the impeller exhaust port) to the low-pressure area (especially the area behind the impeller), causing additional axial force and further increasing the load on the bearing. Currently, to avoid excessive load on the bearing, one way to balance and adjust the axial force is to provide a sealing ring on the back of the impeller. The sealing ring hinders the flow of high-pressure gas from the high-pressure area to the area behind the impeller, reducing the additional axial force caused by gas leakage. However, the sealing ring on the back of the impeller may cause the leakage of high-pressure gas to increase due to wear, which gradually increases the axial force and increases the risk of bearing damage.

[0004] Therefore, how to solve the above-mentioned problem of the prior art, i.e., the increased risk of bearing damage due to wear of the sealing ring, has become a research topic of the present utility model. SUMMARY

[0005] The utility model aims to provide an axial force balance control structure.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0007] An axial force balance control structure is provided for a compressor. The compressor includes an impeller having an intake end in an intake area, an exhaust end in an exhaust area, and a back portion in a back area of the impeller. The axial force balance control structure includes:

[0008] A first sealing ring is provided around the intake end as a component for preventing high-pressure gas discharged from the exhaust end from flowing towards the intake end.

[0009] A second sealing ring is provided around the back portion as a component for preventing high-pressure gas discharged from the exhaust end from flowing towards the back area of the impeller.

[0010] The inner wall of the first sealing ring encloses a ring structure with a size larger than that of the inner wall of the second sealing ring.

[0011] In the above scheme, the size of the ring structure enclosed by the inner wall of the first sealing ring is larger than that of the ring structure enclosed by the inner wall of the second sealing ring, which can prevent the high-pressure gas discharged from the exhaust end from flowing to the intake end and the back region of the impeller, thereby avoiding the generation of additional axial force, increasing the load and wear of the bearing, and prolonging the service life of the bearing.

[0012] By setting the size of the ring structure enclosed by the inner wall of the first sealing ring to be larger than that of the ring structure enclosed by the inner wall of the second sealing ring, the size of the second sealing ring is actually reduced compared to the case where both have the same size, which can reduce the leakage amount when the second sealing ring is gradually worn out, thereby improving the overall efficiency of the compressor.

[0013] In a further technical solution, the first sealing ring and the second sealing ring are both circular ring structures.

[0014] The inner diameter of the cross section of the first sealing ring is larger than that of the second sealing ring.

[0015] The shape of the sealing ring can be set in various ways, and in this part, it is set as a circular ring structure, which has good sealing performance and a wide range of use pressures.

[0016] When a circular ring structure is used, the inner diameter of the cross section of the first sealing ring is larger than that of the second sealing ring.

[0017] Optionally, the outer diameter of the cross section of the first sealing ring is larger than that of the second sealing ring.

[0018] In a further technical solution, the axial force balance control structure further comprises an adjusting assembly for adjusting the pressure of the back region of the impeller.

[0019] It should be noted that when the gas is accelerated and compressed in the impeller, due to the principle of momentum conservation and fluid mechanics, an axial force parallel to the axis of the compressor will be generated; the axial force tries to push the rotor to one end of the compressor, thus generating pressure on the bearing supporting the rotor; if the axial force is not properly balanced or offset, it will cause the bearing to bear excessive load, thereby causing wear, overheating, and even damage to the bearing; the damage to the bearing will seriously affect the performance and reliability of the compressor, and may even cause the entire compressor system to shut down.

[0020] By setting the adjusting assembly, the axial force can be balanced or even offset, avoiding the above problems or reducing the degree of harm caused by the axial force.

[0021] Further technical solutions, the adjusting assembly includes a balance pipeline that communicates the back area of the impeller and the intake area.

[0022] Through the setting of the balance pipeline, the pressure of the back area of the impeller (such as the P2 area in the figure) and the pressure of the intake area (such as the P1 area in the figure) can be balanced, thereby reducing the axial force and improving the stability and efficiency of the compressor.

[0023] Further technical solutions, the adjusting assembly further includes an adjusting valve arranged in the balance pipeline, and the adjusting valve serves as a component for controlling the flow of fluid in the balance pipeline.

[0024] The adjusting valve opening size can be adjusted according to the needs under different working conditions to reduce the overall pressure of the back area of the impeller, thereby reducing the overall axial force. Compared with the way of not setting the adjusting valve but only using the balance pipeline, the way in this part is more flexible.

[0025] It should be emphasized that without the balance pipeline, the axial force is forward (only for convenience of explanation and understanding, without considering the specific direction), and the axial force is large, and the bearing load is large; after the balance pipeline is added, the front and rear pressures are balanced, and the forward axial force is reduced; in some working conditions where the forward axial force is small, only the balance pipeline is added, the rear end pressure becomes small, which may cause the axial force to turn backward, which is not conducive to the use of the bearing, and the adjusting valve added on the balance pipeline can also prevent the axial force from turning backward.

[0026] Further technical solutions, the adjusting assembly further includes a pressure gauge arranged in the balance pipeline, and the pressure gauge serves as a component for displaying the pressure value in the balance pipeline.

[0027] The pressure gauge (or pressure gauge) displays the current pressure value in the balance pipeline by measuring the fluid pressure in the balance pipeline, so that the adjusting valve can timely control the flow of fluid in the balance pipeline.

[0028] Further technical solutions, the impeller has an intake end in the intake area, an exhaust end in the exhaust area, and a back part in the back area of the impeller.

[0029] Further technical solutions, the compressor further includes a front bearing set, a rear bearing set, a main shaft, and a shaft seal.

[0030] The main shaft is connected with the impeller.

[0031] The front bearing set, the rear bearing set, and the shaft seal are all sleeved on the main shaft.

[0032] As used herein, the terms "first", "second", etc. do not particularly refer to order or sequence, nor are they used to limit the present application, but are merely used to distinguish components or operations described by the same technical terms.

[0033] As used herein, the terms "connected" or "positioned" can refer to two or more components or devices being directly or indirectly connected or positioned with respect to one another, and can also refer to two or more components or devices being in operative or communicative connection or engagement with one another.

[0034] As used herein, the terms "comprising", "including", "containing", etc. are open-ended terms that mean "including, but not limited to".

[0035] As used herein, the terms used, unless otherwise specifically noted, generally have their ordinary meanings in the field of use, in the context of the present application, and in the context of the special content. Certain terms used to describe the present application are discussed below or elsewhere in the specification to provide additional guidance to those skilled in the art in understanding the description of the present application.

[0036] As used herein, the terms "front", "back", "up", "down", "left", "right", etc. are directional terms used in the present application only to illustrate the positional relationship between structures, and are not used to limit the scope of protection and the specific direction in actual implementation.

[0037] The working principle and advantages of the utility model are as follows: the gap between the impeller and the compressor shell is prone to gas leakage, and the high-pressure gas discharged from the exhaust end is prone to flowing to the intake end and the back area of the impeller through the gap. The leaked gas in the low-pressure area of the intake area generates additional axial force, increasing the load and wear of the bearing. By setting the first sealing ring and the second sealing ring, the high-pressure gas discharged from the exhaust end can be prevented from flowing to the intake end and the back area of the impeller, thereby avoiding the generation of additional axial force and the increase of the load and wear of the bearing, and prolonging the service life of the bearing. By setting the size of the annular structure formed by the inner wall of the first sealing ring to be larger than the size of the annular structure formed by the inner wall of the second sealing ring, compared with the case where the sizes of the two are the same, the size of the second sealing ring is actually reduced, which can reduce the leakage amount when the second sealing ring is gradually worn out and causes high-pressure gas leakage, thereby improving the overall efficiency of the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The structure diagram of the axial force balance control structure of the utility model embodiment is applied to the compressor.

[0039] Figure 2 The change relationship diagram of the flow coefficient and the pressure head coefficient when the compressor is running.

[0040] In the above attached diagrams: 1. Inlet area; 2. Inlet end; 3. Exhaust area; 4. Exhaust end; 5. Impeller back area; 6. Back part; 7. First sealing ring; 8. Second sealing ring; 9. Adjustment assembly; 91. Balance pipeline; 92. Adjustment valve; 93. Pressure gauge; 10. Front bearing assembly; 11. Rear bearing assembly; 12. Main shaft; 13. Shaft seal. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0042] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0043] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0044] See Figures 1-2 An axial force balance control structure is provided for a compressor, the compressor including an impeller having an inlet end 2 in an inlet region 1, an exhaust end 4 in an exhaust region 3, and a back portion 6 in an impeller back region 5; the axial force balance control structure includes:

[0045] The first sealing ring 7 is sleeved on the air inlet end 2 and serves as a component to prevent high-pressure gas discharged from the exhaust end 4 from flowing to the air inlet end 2.

[0046] The second sealing ring 8 is fitted onto the back portion 6 and serves as a component to prevent the high-pressure gas discharged from the exhaust end 4 from flowing to the impeller back region 5.

[0047] The size of the annular structure formed by the inner wall of the first sealing ring 7 is larger than the size of the annular structure formed by the inner wall of the second sealing ring 8.

[0048] by Figure 1 To explain, Figure 1 The compressor in the compressor is a gear-driven centrifugal compressor, including a main shaft 12, a shaft seal 13, a front bearing assembly 10, and a rear bearing assembly 11, and the gears are helical; see also Figure 2In actual operation, due to changes in suction pressure, exhaust pressure, and motor speed (torque), the magnitude of the axial force on the impeller and helical gear will change, and therefore the direction of the resultant axial force will also change. Thus, the direction of the resultant axial force across the entire operating range of the compressor may be to the left (point a) or to the right (point b). In some cases, the helical gear will generate a horizontal force to the right (all assuming...). Figure 1 The axial force (based on the motor speed and torque) is related to the motor speed and torque. The impeller will generate an overall resultant force with a horizontal axial force to the left.

[0049] This application can be used for gear-driven centrifugal compressors, direct-drive centrifugal compressors, or other types of compressors. When used for direct-drive centrifugal compressors, since there is no axial force behind the gears, the size of the second sealing ring 8 corresponding to the gear-driven centrifugal compressor can be appropriately increased (still smaller than the size of the first sealing ring 7), while the control scheme and method remain unchanged.

[0050] It should be noted that when the gas is accelerated and compressed by the impeller, its pressure and temperature will increase. During this process, the gas not only gains higher kinetic energy, but also stores more pressure energy due to compression. When the gas enters the diffuser or other diffuser through the outlet on the exhaust end 4, its speed gradually decreases, while its pressure further increases. However, due to the gap between the impeller and the compressor housing, some high-pressure gas will leak through this gap to the impeller back area 5, forming a high-pressure area.

[0051] Gas leakage is likely to occur at the gap between the impeller and the compressor housing. High-pressure gas discharged from the exhaust end 4 can easily flow through this gap to the intake end 2 and the impeller back area 5. The leaked gas will generate additional axial force in these low-pressure areas of the intake end 2, increasing the load and wear of the bearing.

[0052] By setting the first sealing ring 7 and the second sealing ring 8, the high-pressure gas discharged from the exhaust end 4 can be prevented from flowing to the intake end 2 and the impeller back area 5, thus avoiding the generation of additional axial force, thereby avoiding increased bearing load and wear, and extending bearing service life.

[0053] By setting the size of the annular structure formed by the inner wall of the first sealing ring 7 (see D1 in the figure) to be larger than the size of the annular structure formed by the inner wall of the second sealing ring 8 (see D2 in the figure), compared to setting both to the same size, the size of the second sealing ring 8 is actually reduced. This reduces leakage when high-pressure gas leaks due to the gradual wear of the second sealing ring 8, thereby improving the overall efficiency and performance of the compressor, especially under high-load conditions (close to...). Figure 2 (Point b in the middle).

[0054] In the embodiment, the first sealing ring 7 and the second sealing ring 8 are both annular structures.

[0055] The inner diameter of the cross section of the first sealing ring 7 is greater than the inner diameter of the cross section of the second sealing ring 8.

[0056] The shape of the sealing ring can be variously set, and in the embodiment, the annular structure is set, which has good sealing performance and a large pressure range.

[0057] Correspondingly, when the annular structure is used, the inner diameter of the cross section of the first sealing ring 7 is greater than the inner diameter of the cross section of the second sealing ring 8.

[0058] Optionally, the outer diameter of the cross section of the first sealing ring 7 is greater than the outer diameter of the cross section of the second sealing ring 8.

[0059] In the embodiment, the axial force balance control structure further comprises an adjusting assembly 9 for adjusting the pressure of the impeller back area 5.

[0060] It should be noted that when the gas is accelerated and compressed in the impeller, due to the principle of momentum conservation and fluid mechanics, a force parallel to the axis of the compressor, i.e., an axial force, will be generated; the axial force attempts to push the rotor to one end of the compressor, thus generating pressure on the bearing supporting the rotor; if the axial force is not properly balanced or offset, it will cause the bearing to bear excessive load, thus causing the bearing to be worn, overheated, or even damaged; the damage of the bearing will seriously affect the performance and reliability of the compressor, and even cause the entire compressor system to be shut down.

[0061] Through the setting of the adjusting assembly 9, the axial force can be balanced or even offset, thereby avoiding the above problems or reducing the damage degree of the axial force.

[0062] In the embodiment, the adjusting assembly 9 comprises a balance pipeline 91 communicating the impeller back area 5 and the gas inlet area 1.

[0063] Through the setting of the balance pipeline 91, the pressure of the impeller back area 5 (such as the P2 area in the figure) and the pressure of the gas inlet area 1 (such as the P1 area in the figure) can be balanced, thereby reducing the axial force and improving the stability and efficiency of the compressor.

[0064] In the embodiment, the adjusting assembly 9 further comprises an adjusting valve 92 arranged in the balance pipeline 91, and the adjusting valve 92 serves as a component for controlling the flow of fluid in the balance pipeline 91.

[0065] When the adjusting valve 92 is completely closed, the balance pipeline 91 cannot communicate the impeller back area 5 and the gas inlet area 1; after the balance pipeline 91 is switched from the open state to the closed state, at this time, the pressure of the impeller back area 5 is higher than the pressure of the gas inlet area 1, and the pressure difference will cause the axial force to be generated; when the adjusting valve 92 is completely opened, the balance pipeline 91 can communicate the impeller back area 5 and the gas inlet area 1, and the pressure of the impeller back area 5 is lower than the pressure of the gas inlet area 1, thus reducing the axial force.Figure 1 In this case, the axial force resultant in the impeller is to the left.

[0066] The opening size of the regulating valve 92 can be adjusted according to the need under different working conditions to reduce the overall pressure of the back region 5 of the impeller, thereby reducing the overall axial force. Compared with the mode of not setting the regulating valve 92 but only using the balance pipeline 91, the mode in this embodiment is more flexible.

[0067] It should be emphasized that, without the balance pipeline 91, the axial force is forward (only for the convenience of explanation and understanding, without considering the specific direction), and the axial force is large, and the bearing load is large; after the balance pipeline 91 is added, the front and rear pressures are balanced, and the forward axial force is reduced; in some working conditions where the forward axial force is small, only the balance pipeline 91 is added, the rear end pressure becomes small, which may cause the axial force to turn backward, which is not conducive to the use of the bearing, and the regulating valve 92 added on the balance pipeline 91 can also prevent the axial force from turning backward.

[0068] Here, a regulating mode is given as a reference, as follows: under the given working condition and demand condition, the compressor is normally started, the initial regulating valve 92 is completely closed, the pressure of the inlet region 1, the pressure of the exhaust region 3 and the pressure in the balance pipeline 91 (set as P3) are detected, the motor input power is set as P, the motor speed is set as n, according to the control logic, the opening size (set as F) of the regulating valve 92 is adjusted, and when P3 decreases to the set value, F remains unchanged.

[0069] In this embodiment, the regulating assembly 9 further comprises a pressure gauge 93 arranged in the balance pipeline 91, and the pressure gauge 93 serves as a component for displaying the pressure value in the balance pipeline 91.

[0070] The pressure gauge 93 (or pressure gauge) displays the current pressure value in the balance pipeline 91 by measuring the fluid pressure in the balance pipeline 91, so as to control the fluid flow in the balance pipeline 91 in time.

[0071] Generally, the pressure gauge 93 can be mechanical, electronic or digital, and the appropriate type is selected according to the specific application environment and demand. In this embodiment, the pressure gauge 93 has a signal output function to indirectly regulate the use of the regulating valve 92. The cooperation between the pressure gauge 93 and the regulating valve 92 is conventional and known to those skilled in the art, and will not be further described here.

[0072] The impeller has an inlet end 2 in the inlet region 1, an exhaust end 4 in the exhaust region 3, and a back part 6 in the back region 5 of the impeller.

[0073] In this embodiment, the compressor further comprises a front bearing set 10, a rear bearing set 11, a main shaft 12 and a shaft seal 13.

[0074] The main shaft 12 is connected with the impeller;

[0075] The front bearing set 10, the rear bearing set 11 and the shaft seal 13 are all sleeved on the main shaft 12.

[0076] The compressor includes but is not limited to a gear-driven centrifugal compressor and a direct-drive centrifugal compressor.

[0077] The main shaft 12, the shaft seal 13 and the bearing set are existing components, and their principles are understood by those skilled in the art, and thus are not described here.

[0078] The above embodiments are only for illustrating the technical concept and characteristics of the utility model, and the purpose is to enable those skilled in the art to understand the content of the utility model and implement it, and it cannot limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit and essence of the utility model should be covered within the protection scope of the utility model.

Claims

1. An axial force balance control structure, intended for a compressor, said compressor comprising an impeller having an intake end (2) in an intake area (1), a discharge end (4) in a discharge area (3) and a back portion (6) in an impeller back area (5); characterized in that: The axial force balance control structure comprises: A first sealing ring (7) is sleeved on the air inlet end (2) as a component for preventing high-pressure gas discharged from the air outlet end (4) from flowing to the air inlet end (2); A second sealing ring (8) is sleeved on the back part (6) as a component for preventing high-pressure gas discharged from the air outlet end (4) from flowing to the impeller back area (5); The size of the annular structure formed by the inner wall of the first sealing ring (7) is greater than the size of the annular structure formed by the inner wall of the second sealing ring (8).

2. The axial force balance control structure according to claim 1, characterized by: Both the first sealing ring (7) and the second sealing ring (8) are circular ring structures. The inner diameter of the cross section of the first sealing ring (7) is greater than the inner diameter of the cross section of the second sealing ring (8).

3. The axial force balance control structure according to claim 1, characterized by: The axial force balance control structure further comprises an adjusting assembly (9) for adjusting the pressure of the impeller back area (5).

4. The axial force balance control structure according to claim 3, characterized by: The adjusting assembly (9) comprises a balance pipeline (91) connecting the impeller back area (5) and the air inlet area (1).

5. The axial force balance control structure according to claim 4, characterized by: The adjusting assembly (9) further comprises an adjusting valve (92) provided in the balance pipeline (91), which is used as a component for controlling the flow of fluid in the balance pipeline (91).

6. The axial force balance control structure according to claim 5, characterized by: The adjusting assembly (9) further comprises a pressure gauge (93) provided in the balance pipeline (91), which is used as a component for displaying the pressure value in the balance pipeline (91).

7. The axial force balance control structure according to claim 1, characterized by: The compressor further comprises a front bearing set (10), a rear bearing set (11), a main shaft (12), and a shaft seal (13); The main shaft (12) is connected with the impeller; The front bearing set (10), the rear bearing set (11), and the shaft seal (13) are all sleeved on the main shaft (12).

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