A micro centripetal turbine sealing device

Abstract

The present invention relates to the field of rotary mechanical seals and discloses a micro centripetal turbine sealing device for use between a housing and a rotating shaft. The device comprises a micro centripetal turbine and a multi-stage sealing element arranged axially. A stage gap is formed between any two adjacent stages of the sealing element. A micro centripetal turbine is disposed within at least one stage gap. The micro centripetal turbine comprises a disk and a plurality of blades. The disk is used to be fixedly mounted on the outer side of the rotating shaft. The outer wall of the disk is a conical structure, and the outer diameter of the end of the disk close to the high-pressure side is larger than the outer diameter of the end of the disk away from the high-pressure side. All blades are disposed on the outer wall of the disk and arranged circumferentially. Each blade can expand and reduce the pressure of the airflow on the high-pressure side, and the end of the disk close to the high-pressure side can shield all blades. Compared with sealing using multi-stage sealing elements, the micro centripetal turbine sealing device can achieve sealing within a shorter axial spacing by utilizing the micro centripetal turbine in conjunction with the sealing element.

Description

Technical Field

[0001] The invention relates to the field of rotary mechanical seals, in particular to a micro centripetal turbine seal device. Background Art

[0002] Rotating machinery is a core component of the process industry and crucial for ensuring safe and reliable production. With advances in engineering technology, my country has made significant progress in the design and manufacturing of rotating machinery, achieving breakthroughs in the localization of high-performance, large-scale rotating machinery. During the 11th Five-Year Plan period, my country experienced a peak in petrochemical development. With the commissioning of million-ton ethylene and tens-million-ton oil refining plants, the primary challenge hindering safe and efficient production in the process industry was, to a certain extent, no longer the large capacity and high-performance rotating machinery, such as compressors and steam turbines. In fact, rotating machinery failures leading to production stoppages for maintenance are a common problem on the production line and the greatest obstacle to long-term, safe and stable operation. The most prominent manifestation of rotating machinery failure is seal leakage. Seal leakage not only affects the efficiency and service life of the machinery but, in industries like the petrochemical industry, the leakage of toxic, hazardous, flammable, and explosive media often causes serious environmental pollution and endangers public safety.

[0003] Currently, the most widely used seal in rotating machinery is the non-contact seal, which can avoid direct contact between the rotating shaft and the sealing device. However, when the non-contact seal is installed, there is a certain gap between the seal and the rotating shaft, and as the machine runs for a longer time, there will inevitably be a certain amount of collision between the rotating shaft and the seal, causing wear and affecting the sealing effect. In order to ensure the sealing effect, the non-contact seal needs to arrange multiple stages of seals along the axial direction, which means that the axial distance must be long enough to meet the space requirements for placing the multi-stage seals. However, an excessively long axial distance will affect the dynamic characteristics of the rotor, making it easy to generate vibrations during the operation of the machine, which is not conducive to the safety of the entire machine operation.

[0004] Therefore, how to achieve sealing within a shorter axial distance has become a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a micro centripetal turbine sealing device to achieve sealing within a shorter axial spacing.

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

[0007] The present invention provides a micro centripetal turbine sealing device, which is used to be arranged between a shell and a rotating shaft, comprising: a micro centripetal turbine and multi-stage sealing elements arranged along the axial direction, a stage gap is formed between any two adjacent stages of the sealing elements, and the micro centripetal turbine is arranged in at least one stage gap, and the micro centripetal turbine comprises a wheel disc and a plurality of blades, the wheel disc is used to be fixedly mounted on the outside of the rotating shaft, the outer wall of the wheel disc is a conical structure, and the outer diameter of the end of the wheel disc close to the high-pressure side is larger than the outer diameter of the end of the wheel disc away from the high-pressure side, all the blades are arranged on the outer wall of the wheel disc, and all the blades are arranged along the circumference of the wheel disc, each of the blades can expand and reduce the pressure of the airflow on the high-pressure side, and the end of the wheel disc close to the high-pressure side can block all the blades.

[0008] Optionally, the blade is a spiral blade.

[0009] Optionally, the thickness of the wheel disc gradually decreases from an end of the wheel disc close to the high-pressure side to an end of the wheel disc away from the high-pressure side, so that the outer side wall of the wheel disc is a tapered structure.

[0010] Optionally, the outer diameter of the wheel disc at one end close to the high-pressure side is greater than the distance between the top end of the blade and the axis of the rotating shaft, so that the wheel disc at one end close to the high-pressure side can cover all the blades.

[0011] Optionally, there are multiple micro centripetal turbines, and all of the micro centripetal turbines are respectively arranged in the stage intervals at different positions.

[0012] Optionally, the outer side wall of the wheel disc is a curved structure.

[0013] Optionally, a plurality of annular grooves are axially arranged on the inner wall of the shell, the sealing members correspond to the annular grooves one by one, each of the sealing members is partially embedded in the corresponding annular groove, and a gasket for positioning the two adjacent levels of the sealing members is provided between any two adjacent annular grooves.

[0014] Optionally, there is a gap between the outer side wall of one end of the wheel disc close to the high-pressure side and the gasket.

[0015] Optionally, the seal is a carbon ring.

[0016] Compared with the prior art, the present invention has achieved the following technical effects:

[0017] The micro centripetal turbine sealing device provided by the present invention is used to be arranged between a shell and a rotating shaft, and includes: a micro centripetal turbine and a multi-stage sealing element arranged along the axial direction, a stage gap is formed between any two adjacent stage sealing elements, and a micro centripetal turbine is arranged in at least one stage gap. The micro centripetal turbine includes a wheel disc and multiple blades. The wheel disc is used to be fixedly mounted on the outside of the rotating shaft. The outer wall of the wheel disc is a conical structure, and the outer diameter of the end of the wheel disc close to the high-pressure side is larger than the outer diameter of the end of the wheel disc away from the high-pressure side. All blades are arranged on the outer wall of the wheel disc, and all blades are arranged along the circumference of the wheel disc. Each blade can expand and reduce the pressure of the airflow on the high-pressure side, and the end of the wheel disc close to the high-pressure side can block all blades.

[0018] During use, the disc rotates synchronously with the shaft, and the blades rotate synchronously with the disc. As the blades rotate, they expand the high-pressure airflow, i.e., the airflow entering between the shaft and the housing from the high-pressure side, converting the pressure energy of the airflow into mechanical energy, thereby reducing the pressure energy of the airflow. Simultaneously, the end of the disc closest to the high-pressure side can obstruct the flow of airflow. Thus, compared to sealing using multi-stage seals, the micro-centrifugal turbine sealing device provided by the present invention, by adding a micro-centrifugal turbine and utilizing the micro-centrifugal turbine in conjunction with the seal, can achieve sealing within a shorter axial spacing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A cross-sectional view of a micro centripetal turbine sealing device provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the arrangement of a micro centripetal turbine in a micro centripetal turbine sealing device provided in an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the velocity triangle of the blades of the micro centripetal turbine sealing device provided in an embodiment of the present invention;

[0023] Figure 4 A comparison diagram of the sealing effects of the micro centripetal turbine sealing device provided in an embodiment of the present invention and a conventional sealing method;

[0024] Figure 5 A sealing principle diagram of a micro centripetal turbine sealing device provided in an embodiment of the present invention;

[0025] Figure 6The sealing principle diagram of the non-contact seal mentioned in the background technology.

[0026] Figure 1-Figure 5 Explanation of the reference numerals: 100, micro centripetal turbine sealing device; 1, housing; 2, rotating shaft; 3, seal; 4, micro centripetal turbine; 401, wheel disc; 402, blade; 5, gasket; 6, gap; 7, void.

[0027] Figure 6 Description of reference numerals: 1', rotating shaft; 2', sealing member. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The object of the present invention is to provide a micro centripetal turbine sealing device capable of achieving sealing within a shorter axial distance.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] refer to Figure 1-Figure 5 As shown, the micro centripetal turbine sealing device 100 provided in this embodiment is used to be arranged between the housing 1 and the rotating shaft 2, and includes: a micro centripetal turbine 4 and a multi-stage sealing member 3 arranged along the axial direction.

[0032] Specifically, a stage gap is formed between any two adjacent stage seals 3, and a micro centripetal turbine 4 is provided in at least one stage gap. The micro centripetal turbine 4 is preferably provided between the high-pressure side and the low-pressure side, closer to the high-pressure side. It should be noted that one side of the two sides of the micro centripetal turbine sealing device 100 has a high pressure and the other side has a low pressure. The side with high pressure is the high-pressure side, and the side with low pressure is the low-pressure side. The micro centripetal turbine sealing device 100 provided in this embodiment is in accordance with Figure 1 When arranged in the manner shown, the left side is the high-pressure side and the right side is the low-pressure side. Figure 1 The arrow in the middle indicates the direction of air flow.

[0033] like Figure 2As shown, the micro centripetal turbine 4 includes a disc 401 and a plurality of blades 402. The disc 401 is used to be fixedly mounted on the outside of the rotating shaft 2. As the rotating shaft 2 rotates synchronously, the outer wall of the disc 401 is a conical structure, and the outer diameter of the end of the disc 401 close to the high-pressure side is larger than the outer diameter of the end of the disc 401 away from the high-pressure side. All blades 402 are arranged on the outer wall of the disc 401. As the disc 401 rotates synchronously, all blades 402 are arranged along the circumference of the disc 401. For example, all blades 402 are evenly arranged along the circumference of the disc 401. Each blade 402 can expand and reduce the pressure of the airflow on the high-pressure side, and the end of the disc 401 close to the high-pressure side can block all blades 402.

[0034] During specific use, the wheel disc 401 rotates synchronously with the shaft 2, and the blades 402 rotate synchronously with the wheel disc 401. When the blades 402 rotate, they can expand the high-pressure side airflow, that is, the airflow entering between the shaft 2 and the housing 1 from the high-pressure side, converting the pressure energy of the airflow into mechanical energy, thereby reducing the pressure energy of the airflow. At the same time, the end of the wheel disc 401 close to the high-pressure side can hinder the flow of the airflow and prevent the high-pressure side airflow from directly rushing to the low-pressure outlet along the axial direction. In this way, compared with sealing using a multi-stage seal 3, the micro-centrifugal turbine sealing device 100 provided by the present invention can achieve sealing within a shorter axial spacing by adding a micro-centrifugal turbine 4 and using the micro-centrifugal turbine 4 to cooperate with the seal 3.

[0035] In this embodiment, if Figure 2 As shown, the blades 402 are spiral blades, and the bending direction of each blade 402 close to the high-pressure side is the same as the rotation direction of the shaft 2, and the bending direction of each blade 402 away from the high-pressure side is opposite to the rotation direction of the shaft 2.

[0036] In this embodiment, if Figure 2 As shown, the thickness of the wheel disc 401 gradually decreases from the end of the wheel disc 401 close to the high-pressure side to the end of the wheel disc 401 away from the high-pressure side, so that the outer wall of the wheel disc 401 is a tapered structure.

[0037] In this embodiment, the outer diameter of the wheel disc 401 near the high pressure side is larger than the distance between the top of the blade 402 and the axis of the shaft 2, so that the wheel disc 401 near the high pressure side can cover all the blades 402.

[0038] In this embodiment, if Figure 2 As shown, there are multiple micro centrifugal turbines 4, all of which are respectively arranged in stage intervals at different positions. The number of micro centrifugal turbines 4 and the positions of the stage intervals in which the micro centrifugal turbines 4 are arranged are determined according to actual needs.

[0039] In this embodiment, if Figure 2As shown, the outer side wall of the wheel disc 401 is a curved structure.

[0040] In this embodiment, a plurality of annular grooves are axially arranged on the inner wall of the shell 1, and the seals 3 correspond to the annular grooves one by one. Each seal 3 is partially embedded in its corresponding annular groove, and a gasket 5 for positioning the adjacent two-stage seals 3 is provided between any two adjacent annular grooves.

[0041] Further, if Figure 1 As shown, at least part of the gaskets 5 is an inverted L-shaped structure, a mounting cavity is provided on the inner wall of the housing 1 , all the L-shaped gaskets 5 are arranged side by side, and an annular groove is formed between any two adjacent gaskets 5 .

[0042] In this embodiment, a gap 6 is formed between the outer wall of the end of the wheel disc 401 close to the high-pressure side and the gasket 5. Specifically, in this embodiment, the size of the gap 6 is 0.1 mm to 0.2 mm.

[0043] In this embodiment, the sealing member 3 is a carbon ring. It should be noted that the sealing member 3 is not limited to a carbon ring, and other structures that can achieve non-contact sealing can also be selected.

[0044] During specific use, the micro centripetal turbine 4 blades 402 are designed and matched according to the rotation direction of the shaft 2, the pressure conditions before and after the micro centripetal turbine sealing device 100, and the working conditions of the gap 7 between the seal 3 and the shaft 2. The design contents include: the size of the blade 402, the consistency of the blade 402, and the gap 6 between the wheel disc 401 and the gasket 5.

[0045] The following combination Figure 3 The pressure reduction and flow diversion principles of the micro centripetal turbine 4 provided in this embodiment are described in detail:

[0046] Figure 3 The velocity triangle of the blades 402 of the micro centripetal turbine 4 is shown. The rotation direction of the shaft 2 is counterclockwise. First, the airflow passes through the first-stage seal 3 and flows into the first-stage micro centripetal turbine 4. When the airflow flows between two adjacent blades 402, it continues to expand and do work, converting pressure energy into mechanical energy. Figure 3 It can be seen that C2 is significantly smaller than C1. Secondly, the end of the wheel 401 close to the high-pressure side also blocks the high-pressure side airflow, reducing the high-pressure gas from flowing to the outlet. Figure 3 Where W1 is the relative velocity at the inlet of the blade 402, W2 is the relative velocity at the outlet of the blade 402, C1 is the absolute velocity at the inlet of the blade 402, C2 is the absolute velocity at the outlet of the blade 402, and U is the circumferential velocity.

[0047] The following combination Figure 4-Figure 6 The advantages of the micro centripetal turbine sealing device 100 provided in this embodiment are described in detail below:

[0048] Figure 4 A schematic diagram comparing the sealing effect of the micro-centrifugal turbine 4 provided in this embodiment and the conventional sealing method is given. The placement position of the axial seal 3 corresponds to the line diagram. Figure 4 The micro-centrifugal turbine sealing device 100 provided in this embodiment takes a two-stage micro-centrifugal turbine 4 coupled to a three-stage carbon ring seal 3 as an example, and a conventional sealing method takes a multi-stage carbon ring as an example. For the sake of convenience, the method of coupling a two-stage micro-centrifugal turbine 4 to a three-stage carbon ring seal 3 will be referred to as a micro-centrifugal turbine sealing method, and the conventional multi-stage carbon ring sealing method will be referred to as a non-micro-centrifugal turbine sealing method. In the non-micro-centrifugal turbine sealing method, since the micro-centrifugal turbine 4 is not provided, a cavity is formed between the gasket 5 and the rotating shaft 2. The horizontal axis is the axial direction from the high-pressure inlet to the low-pressure outlet, and the vertical axis is the total pressure and leakage, respectively. Under the same inlet pressure and the same rotating shaft 2 speed, the micro-centrifugal turbine sealing method can reach the low-pressure outlet pressure value faster than the non-micro-centrifugal turbine sealing method. The micro-centrifugal turbine sealing method requires fewer carbon ring stages and thus requires a shorter axial spacing. Furthermore, compared to a non-micro-centrifugal turbine seal, the micro-centrifugal turbine seal provided in this embodiment prevents a significant pressure drop in the final carbon ring at the outlet, thus minimizing damage to the carbon ring. Furthermore, the micro-centrifugal turbine seal provided in this embodiment provides a barrier to airflow, preventing high-pressure airflow from axially colliding with the low-pressure outlet.

[0049] It should be noted that, compared with conventional centrifugal turbines, the centrifugal turbine provided in the embodiment of the present invention is disposed between the housing 1 and the rotating shaft 2. The size of the centrifugal turbine in the present invention is much smaller than that of conventional centrifugal turbines. Therefore, the centrifugal turbine in the present invention is referred to as a micro-centrifugal turbine. The term "micro" here does not mean that the size of the micro-centrifugal turbine 4 must be smaller than a certain value. The size of the micro-centrifugal turbine 4 is adjusted according to sealing requirements. It should also be noted that the structure of the micro-centrifugal turbine 4 provided in the embodiment of the present invention is substantially the same as that of a conventional centrifugal turbine.

[0050] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A micro centripetal turbine sealing device, characterized in that: It is used to be arranged between a shell and a rotating shaft, and includes: a micro centripetal turbine and multi-stage sealing members arranged along the axial direction. A stage gap is formed between any two adjacent stages of the sealing members. The micro centripetal turbine is arranged in at least one stage gap. The micro centripetal turbine includes a wheel disc and a plurality of blades. The wheel disc is used to be fixedly mounted on the outside of the rotating shaft. The outer wall of the wheel disc is a conical structure, and the outer diameter of the end of the wheel disc close to the high-pressure side is larger than the outer diameter of the end of the wheel disc away from the high-pressure side. All the blades are arranged on the outer wall of the wheel disc, and all the blades are arranged along the circumference of the wheel disc. Each of the blades can expand and reduce the pressure of the airflow on the high-pressure side, and the end of the wheel disc close to the high-pressure side can block all the blades.

2. The micro centripetal turbine sealing device according to claim 1, characterized in that: The blades are spiral blades.

3. The micro centripetal turbine sealing device according to claim 1, characterized in that: The thickness of the wheel disc gradually decreases from one end of the wheel disc close to the high-pressure side to one end of the wheel disc away from the high-pressure side, so that the outer side wall of the wheel disc is a tapered structure.

4. The micro centripetal turbine sealing device according to claim 1, characterized in that: The outer diameter of the wheel disc at one end close to the high-pressure side is greater than the distance between the top end of the blade and the axis of the rotating shaft, so that the wheel disc at one end close to the high-pressure side can cover all the blades.

5. The micro centripetal turbine sealing device according to claim 1, characterized in that: There are multiple micro centripetal turbines, and all of the micro centripetal turbines are respectively arranged in the stage intervals at different positions.

6. The micro centripetal turbine sealing device according to claim 1, characterized in that: The outer side wall of the wheel disc is a curved structure.

7. The micro centripetal turbine sealing device according to claim 1, characterized in that: A plurality of annular grooves are axially arranged on the inner wall of the shell, and the sealing members correspond to the annular grooves one by one. Each sealing member is partially embedded in the corresponding annular groove, and a gasket for positioning the two adjacent sealing members is provided between any two adjacent annular grooves.

8. The micro centripetal turbine sealing device according to claim 7, characterized in that: A gap is defined between an outer side wall of one end of the wheel disc close to the high-pressure side and the gasket.

9. The micro centripetal turbine sealing device according to claim 1, characterized in that: The sealing member is a carbon ring.

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