Non-contact self-impact seal having efficient throttling effect and fixed gap

Abstract

A non-contact self-impact seal having an efficient throttling effect and a fixed gap. The non-contact self-impact seal is formed by assembling a static ring (1), a dynamic ring (2) and a suspension column (7), wherein the static ring, the dynamic ring and the suspension column are all rigidly fixed; the suspension column is respectively arranged in the static ring or the dynamic ring according to an assembly relationship; a non-contact gap formed after the static ring, the dynamic ring and the suspension column are rigidly fixed forms a fluid channel; the fluid channel is composed of an inlet, an outlet and a laminated arrangement structure; the laminated arrangement structure is composed of several self-impact units; the self-impact unit specifically comprises the fluid channel; a first bifurcated opening (3) of the fluid channel is divided into an oblique channel and a curved channel; and the curved channel converges with the oblique channel again after a U-turn to form a second bifurcated opening (4). The non-contact self-impact seal has the advantages of a stable seal gap, leak suppression performance independent of the rotating speed of a main shaft, a simple structure, a simple system, etc.; and the arrangement mode is a lamination form, and can be a series arrangement and a stepped arrangement, such that the throttling efficiency is more efficient.

Description

A non-contact self-impact seal with high throttling efficiency and fixed gap Technical Field

[0001] The invention belongs to the technical field of rotating fluid mechanical equipment, and in particular relates to a non-contact self-impact seal with high throttling efficiency and fixed gap. Background Art

[0002] With technological advancements and industrial development, the demand for practical high-parameter mechanical seals is becoming increasingly stringent. The latest API-682 standard stipulates that sealing systems must operate stably for at least three years (25,000 hours) of continuous operation. The limitations of traditional mechanical seals are becoming increasingly apparent under these high-parameter conditions: high power consumption, severe wear, and limited lifespan. Non-contact mechanical seals based on hydrodynamic lubrication, featuring zero leakage, low power consumption, and long life, are experiencing rapid development. High-performance non-contact mechanical seals have become a key focus of advanced sealing technology research and development both domestically and internationally. As early as 2012, non-contact seals, represented by brush and dry gas seals, were included as advanced sealing technologies in the US "Advanced Gas Turbine Sealing and Leakage Control Strategies" and have successfully replaced the original mechanical seals on the PW2000 engine, completing thousands of flight test hours. Numerous domestic researchers have been dedicated to the technical promotion, theoretical research, and domestication of non-contact mechanical seals. However, high-performance sealing products continue to rely on imports, and are subject to limited supply cycles and quantities, severely restricting the development and application of high-end equipment technology.

[0003] The current state of research in non-contact mechanical seal technology at home and abroad. In the 1950s, the development of the nuclear power industry necessitated an urgent need for high-PV mechanical seals. Consequently, non-contact seals primarily based on hydrostatic, dynamic, and thermal hydrodynamic pressure emerged. By the 1960s, various types of hydrostatic and dynamic seals had gradually gained industrial application. Driven by the demands of aerospace and nuclear power, new sealing materials such as silicon carbide and high-quality carbon graphite emerged in the 1970s, and multi-stage and combined seals such as spiral, floating ring, and spiral groove seals gained prominence. Since the 1980s, increasing environmental protection requirements have led to the introduction of various new standards (such as API 610, API 682, and STLE SP-30). Laser processing, surface modification, and computer technology have significantly promoted theoretical advances and performance improvements in non-contact mechanical seals. Achieving zero leakage and zero escape of media is a key characteristic of non-contact seals, but the specific leakage suppression methods and mechanisms vary. The following analyzes the current state of research in four representative types of non-contact mechanical seals.

[0004] (1) Labyrinth seals

[0005] Labyrinth seals are an effective sealing structure widely used in modern aircraft engines, steam turbines, and other power machinery. They feature a simple structure, are frictionless, have a long lifespan, and are easy to maintain. Their primary operating mechanism is the throttling of the gap between the seal teeth and the dissipation of kinetic energy in the inter-tooth cavity. These effects include friction, velocity contraction, air permeability, and thermodynamics. Thermodynamics is the primary driver of labyrinth seals, while friction contributes to the sealing effect, while fluid contraction and air permeability weaken it. In the 1980s, the MK-152 engines used by my country's civil aviation fleet were replaced prematurely due to excessive oil consumption. Switching to labyrinth seals resulted in a 40.7% reduction in fuel consumption. NASA's AST program, implemented in the 1990s, demonstrated that for every 10% reduction in aircraft engine fuel efficiency, improvements to labyrinth seal technology accounted for 2% to 3% of this reduction. The practical application of my country's new fighter jet engines also demonstrates that by rationally improving the sealing performance of labyrinth seals, their efficiency can be significantly increased by 10%. However, at present, labyrinth seals still have shortcomings, mainly manifested in: the air permeability effect is significant, the energy of the sealed medium cannot be fully dissipated, and the sealing efficiency is continuously lost; airflow excitation problems will also occur under high parameters, which can easily cause the sealed rotor system to become unstable and reduce the sealing stability.

[0006] (2) Dry gas seal

[0007] Dry gas seal technology, based on the principles of dynamic and static pressure, features low wear, long life, and zero leakage, making it ideally suited for high-speed applications. In the 1960s, NASA, Pratt & Whitney Aircraft (PWA), and General Electric (GE) began exploring the application of this technology in critical, high-speed aircraft engine components. John Crane's range of dry gas seals has found widespread application in compressors, steam turbines, and industrial pumps. Since the introduction of this technology in China in the 1990s, universities such as Tsinghua University, Xi'an Jiaotong University, Beihang University, and Harbin Institute of Technology have conducted extensive theoretical and experimental research, effectively promoting the localization of this technology. In terms of industrial development, companies such as Rimi Holdings, SINOMACH, and Hefei General Research Institute have also developed a series of products that have been successfully applied. However, compared to foreign countries, there is still a certain gap, especially in the field of high-performance products. Currently, the maximum operating pressure of foreign dry gas seals can reach 10,000 psi (approximately 69 MPa) and a linear speed of 250 m / s (at 65 MPa). The maximum field application pressure of domestic dry gas seals is approximately 25 MPa, corresponding to a linear speed of less than 230 m / s. Furthermore, due to the influence of the permeability effect, a single dry gas seal cannot meet leakage requirements. In practice, several seals are often used in combination. During normal operation, the gas film thickness is only approximately 2-5 μm, and the stability of the gas film and system at the mesoscale is also not optimistic. Furthermore, the core technology of dry gas seals lies in the precision machining of 3-10 μm grooves (Ra < 0.8 μm), and this high-efficiency and precision manufacturing method has been blocked by foreign technology.

[0008] (3) Upstream pumping seal

[0009] Upstream pumping seals, derived from gas-lubricated bearing technology, are primarily used for liquid media. By pumping the sealing medium from the low-pressure side to the high-pressure side, they achieve low or even zero leakage in a non-contact manner. The first patent for upstream pumping seals was granted in 1981. Since the 1990s, research on this technology has steadily increased. The spiral groove type has proven to be highly effective in suppressing leakage, resulting in a series of products successfully applied in industry. In 2014, Smith designed a new upstream pumping seal with anti-fouling properties and demonstrated its reliability through case studies. In 2018, Warda et al. proposed a bidirectional integral pumping seal device with excellent sealing performance. The first patent for upstream pumping seals in China was granted in 1990. Currently, teams including Wang Yuming of Tsinghua University, Hao Muming of China University of Petroleum, Song Pengyun of Kunming University of Science and Technology, Zhu Weibing of Xihua University, and Chen Huilong of Jiangsu University have conducted numerous valuable research on upstream pumping seals through theoretical analysis and experimental research. At present, upstream pumping mechanical seals are mostly used in situations where the rotation speed is not high (<3000 rpm). In multiple working conditions and reverse rotation environments, the lack of obvious dynamic pressure effect is a prominent problem. In severe cases, it will cause the sealing ring to wear and cause seal failure.

[0010] (3) Magnetic fluid seal

[0011] The world's first patent for a magnetic fluid seal was filed by American scientist Rosensweig in 1948. Subsequently, scientists have conducted extensive research on the mechanical and thermodynamic properties, preparation processes, and other aspects of magnetic fluid sealing, focusing on sealing functions. The introduction of a combined magnetic fluid seal structure has effectively improved the seal's pressure resistance. Technologies such as multi-lip / inner and outer seal cooling channels and Peltier semiconductor refrigeration have further enhanced the seal's high-temperature resistance. Split-flap magnetic fluid seals have successfully solved the problem of seal assembly and replacement in complex equipment. In the 1970s, foreign scholars began studying the use of magnetic fluid to seal liquids. The results showed that the applicable speed of magnetic fluid seals in liquid environments is not high. Domestic scholars have also conducted extensive research on magnetic fluid liquid medium sealing. Li Decai of Beijing Jiaotong University, Li Wenchang of Beijing University of Chemical Technology, and Gu Jianming of Shanghai Jiaotong University have conducted in-depth research on the structure and force of magnetic fluid seals. In general, magnetic fluids have low resistance to high pressure, high temperature and linear speed when used to seal gases. Especially when used to seal liquids, the sealing performance is greatly affected by the spindle speed and is only suitable for lower speeds (<1500 rpm is better). To date, the principles and failure mechanisms of magnetic fluid sealing liquids are still not fully understood.

[0012] In summary, non-contact mechanical seals are still imperfect. Specifically, they exhibit the following: ① Most seal structures exhibit a straight-through breathability effect, resulting in high leakage and low sealing efficiency (e.g., labyrinth, dry gas, spiral, and gap seals); ② They are overly dependent on spindle speed, resulting in loss of sealing capability during startup and shutdown (e.g., dry gas, centrifugal, and upstream pumping seals); ③ They are less adaptable to high-speed or high-pressure operating conditions (e.g., magnetic fluid and spiral seals); ④ Auxiliary devices are complex, resulting in poor system stability (e.g., dry gas, upstream pumping, and spiral seals). Despite these drawbacks, non-contact sealing methods without solid-phase friction remain the optimal form of sealing for high-parameter operating conditions. If innovative fluid blocking mechanisms can be employed to enhance sealing efficiency and avoid excessive dependence or speed constraints on sealing performance while maintaining a simple structure and high stability, this could represent a significant technological innovation in the field of non-contact sealing.

[0013] Type your technical problem description paragraph here. Technical Solutions

[0014] The purpose of the present invention is to design a non-contact self-impact seal with high throttling efficiency and fixed gap, which has the advantages of stable sealing gap, no dependence on spindle speed, high throttling efficiency, simple structure and concise system.

[0015] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0016] A non-contact self-impact seal with efficient throttling and fixed gap, the non-contact self-impact seal is composed of a static ring, a dynamic ring and a suspension column. The static ring, the dynamic ring and the suspension column are all rigidly fixed. The suspension column is placed in the static ring or the dynamic ring according to the assembly relationship. The non-contact gap formed after the static ring, the dynamic ring and the suspension column are rigidly fixed constitutes a fluid channel. The fluid channel consists of an inlet, an outlet and a stacked arrangement structure. The stacked arrangement structure consists of a number of self-impact units. The self-impact unit specifically includes a fluid channel. The first bifurcation of the fluid channel divides into an oblique channel and a curved channel. The curved channel, after a large turn, intersects with the oblique channel again to form a second bifurcation.

[0017] Furthermore, the arrangement of the self-impact units can be composed of one or more combinations of symmetrical, positively staggered, and negatively staggered according to the arrangement relationship between the adjacent first bifurcation and the second bifurcation. Combined with experimental research, it is shown that the positively staggered structure has a better leakage suppression effect.

[0018] Furthermore, the stacked arrangement structure is specifically formed by a series combination of several self-impact units, and the series combination includes a single-row, double-row or multi-row arrangement style.

[0019] Furthermore, the double-row arrangement is to design the static ring into two parts that can be connected by bolts or interference fit, and sealed with a sealing ring in the middle. From the perspective of facilitating assembly, the suspension column is placed in the dynamic ring or the static ring, and the entire assembly can be completed in sequence in axial order. When arranging in multiple rows, the static ring and the dynamic ring are further split and then connected in series as a whole.

[0020] Furthermore, during assembly, the dynamic ring is rigidly fixed to the shaft or sleeve by means of set screws, keys or interference fit, and the static ring is rigidly connected to the gland or body by means of anti-rotation pins, keys or interference fit.

[0021] Furthermore, a single-row, double-row or multi-row structural arrangement style is adopted, and the static ring and the dynamic ring can be installed on the shaft or sleeve in axial order, or the seal can be assembled as a whole and then directly installed on the shaft or sleeve. Beneficial effects

[0022] Compared with traditional seals, the non-contact self-impact seal proposed by this technology has outstanding advantages:

[0023] Stable sealing gap: The non-contact self-impact seal dynamic and static rings are rigidly fixed, which can maintain stable, large-gap non-contact operation during operation, greatly improving the dynamic performance of the sealing pair to resist axial / radial vibration.

[0024] Independent of spindle speed: The non-contact, self-impact seal utilizes the impact blockage of the fluid within the three-dimensional Tesla valve channel to achieve progressive throttling and leakage control of the sealing medium. Theoretically, the number of stages and seal spacing are key to achieving standard or even zero leakage, and the leakage control effect is largely unaffected by spindle speed. Research has shown that under certain operating conditions, when the speed increases from 5,000 rpm to 50,000 rpm, the leakage increase does not exceed 3%.

[0025] Simple structure and concise system: The non-contact self-impact seal has few components and a simple structure. To save space, the static ring can also be directly supported by the sealing end cover or housing. Since the performance is not limited by the spindle speed, the system does not require complex parking assistance devices.

[0026] The stacked structure has various layout forms and high efficiency; the suspension columns are placed on the corresponding dynamic and static rings respectively, which enables simple assembly of the suspension columns. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a schematic diagram of a non-contact self-impact seal single-row stacked structure.

[0028] Figure 2 is a layout diagram of a symmetrical self-impact unit.

[0029] Figure 3 is a diagram showing the arrangement of orthogonal staggered self-impact units.

[0030] Figure 4 is a layout diagram of the negative staggered self-impact unit.

[0031] Figure 5 is a schematic diagram of a double-row combination.

[0032] FIG6 is a schematic diagram of a multi-column series combination.

[0033] Figure 7 is a single-row structure assembly drawing.

[0034] Figure 8 is a multi-column structure assembly drawing.

[0035] FIG9 is a diagram showing the effect of the staggered ratio on seal leakage.

[0036] Figure 10 shows five typical non-contact sealing structures.

[0037] Figures 11(a)-11(h) are schematic diagrams of the stacked structures of Figures 11(a), 11(b), 11(c), and 11(d) and their corresponding series of Figures 11(e), 11(f), 11(g), and 11(h).

[0038] In the picture:

[0039] In the figure: 1, static ring; 2, dynamic ring; 3, first bifurcation; 4, second bifurcation; 5, curved channel; 6, inclined channel, 7, suspension column. Best Mode for Carrying Out the Invention

[0040] The present invention will be further described below with reference to the accompanying drawings:

[0041] As shown in Figure 1, the static ring 1 and the dynamic ring 2 specifically adopt a single-row stacked arrangement structure. The non-contact self-impact seal is composed of the static ring 1, the dynamic ring 2, and the suspension 7. From the perspective of facilitating assembly, the suspension is placed in the dynamic ring or the static ring. The static ring, the dynamic ring, and the suspension are all rigidly fixed. The suspension is placed in the static ring or the dynamic ring according to the assembly relationship. The non-contact gap formed by the rigid fixation of the static ring, the dynamic ring, and the suspension constitutes a fluid channel. The fluid channel consists of an inlet, an outlet, and a stacked arrangement structure. The stacked arrangement structure is composed of several self-impact units. The self-impact unit specifically includes a fluid channel. The first bifurcation 3 of the fluid channel branches into an oblique channel 6 and a curved channel 5. The curved channel, after a large turn, intersects with the oblique channel again to form a second bifurcation 4. This structure has a high radial arrangement efficiency. The stacked arrangement structure can also be designed in a symmetrical, positively staggered, negatively staggered, and other forms. Specifically corresponding to Figures 2, 3 and 4, Figure 2 shows a symmetrical arrangement of the self-impact units, and its structure is that the bifurcations of adjacent self-impact units are shared, and the second bifurcation of the lower self-impact unit in Figure 2 is shared with the first bifurcation of the upper self-impact unit; Figures 3 and 4 show a staggered arrangement of the self-impact units, and the second bifurcation of the lower self-impact unit and the first bifurcation of the upper self-impact unit are staggered in front and behind.

[0042] As can be seen from the above, the specific position of the fluid channel is determined by the stagger value. Considering the influence of the seal spacing h, the stagger ratio k = e / h (e is the stagger value) is defined as a dimensionless representation value that measures the positive and negative stagger of the series unit. Figure 9 shows the effect of the stagger ratio change on seal leakage under different seal spacings. It can be seen that the seal leakage is the largest when the stagger is negative and remains high, which may be due to the fluid backflow lag caused by the negative stagger. When there is no stagger, that is, k = 0, the leakage is between the negative stagger and the positive stagger. After that, as the positive stagger ratio increases, the leakage shows a trend of first decreasing and then increasing. The change trends under different seal spacings are similar. The leakage is the smallest when the stagger ratio k = 2 (the stagger value is twice the seal spacing). In summary, the stagger ratio has a significant impact on seal leakage. Positive staggering is conducive to improving the leakage suppression effect. When the stagger ratio k = 2, the lowest leakage can be achieved without making the seal series unit too wide.

[0043] Based on the above basic structural characteristics, a series combination structure was designed. Increasing the number of seal stages and impact units is an effective means of improving leakage suppression and reducing leakage. However, with a single-row stacked design, the greater the number of stages, the larger the axial dimension of the seal, and the inlet and outlet (annular) areas on both sides of the seal differ. This can severely limit the actual usable space of the seal. To address this issue, a double-row or multi-row combination design can be adopted, achieving an axial arrangement of seal stages within a certain radial dimension. As shown in Figures 5 and 6, the static ring is further designed into two parts that can be connected by bolts, with a sealing ring in the middle. This allows the assembly of the three parts, the dynamic and static rings, to be completed sequentially. Multiple-row combinations can be connected in series using the double-row configuration.

[0044] The above-mentioned model structure can be adopted in a single-row configuration when axial space is limited but radial space is abundant, as shown in Figure 7. The dynamic ring is fixed to the shaft or sleeve with set screws, and the static ring is fixed to the gland with an anti-rotation pin. Other leakage points are statically sealed by sealing rings. If the sealing gas is dirty, a high-pressure flushing medium can be introduced to impact the inlet to ensure the cleanliness of the fluid.

[0045] Figure 8 shows a multi-row assembly. This structure fully utilizes the axial dimension and is suitable for applications where radial space is insufficient. The dynamic and static rings are installed sequentially from right to left. Alternatively, the seal can be assembled as a whole and then mounted directly on the shaft or sleeve, depending on the actual situation.

[0046] The new non-contact, self-impact seal, featuring efficient throttling and a fixed clearance, is a passive fluid-controlled blocking seal technology. As the fluid flows through the channel, it experiences an internal impact of fluid pulses at each stage, dissipating the fluid energy step by step. This structure, based on the flat Tesla valve, is expanded into a three-dimensional cylindrical channel. The seal structure is simple, with no additional moving parts. This non-contact mechanical seal eliminates direct solid-phase contact, offers low power consumption and low wear, making it suitable for high-speed applications.

[0047] From the perspective of sealing form, the new seal has an energy conversion mechanism with leakage suppression function: ① The fluid has a friction effect at high speed, and the kinetic energy is dissipated by converting it into heat energy, which is conducive to leakage suppression (same as maze, gap, spiral, dry gas seal, etc.); ② The impact blocking effect is more significant, and the direct convection impact blocking effect of each single-stage seal in the closed system without the action of pressure difference makes the throttling efficiency more prominent (same as upstream pumping, spiral, dry gas seal, etc.), and the kinetic energy of the fluid is quickly converted into heat energy and dissipated; ③ When the fluids converge and impact, they contract, which reduces the pressure and increases the speed of the fluid flowing in the low-pressure direction, and the pressure energy is converted into kinetic energy, that is, the flow contraction effect (same as maze, spiral seal, etc.); ④ After the intersection impact, the velocity direction of part of the fluid will change, driving the fluid in the channel to form a vortex at the intersection and turning point, continuously expanding and compressing, so that the kinetic energy of the gas is converted into heat energy and dissipated, that is, the thermodynamic effect (same as maze, spiral, dry gas seal, etc.). The impact blocking effect is the main reason for the new seal to suppress leakage. It has high throttling efficiency and can be achieved step by step. There is no significant permeability effect common to most non-contact seals, which is conducive to greatly improving the energy dissipation efficiency of the fluid.

[0048] The proposed new non-contact self-impact seal, which features efficient throttling and a fixed gap, is arranged in a stacked format and can be arranged in series. Figure 10 shows the typical structures of non-contact seals, including gap seals, labyrinth seals, spiral seals, and dry gas seals. It can be seen that these non-contact seal structures all have straight-through flow channels, within which fluid can leak out unimpeded, resulting in reduced sealing efficiency. However, each level of the flow channel within the new seal has an impact-blocking effect on the fluid. This structural step-by-step impact-blocking feature of the new seal can make throttling more efficient. Table 1 shows a comparison of leakage of various non-contact mechanical seals. It can be seen that under the same operating conditions, using leakage as an indicator, the new seal can reduce leakage by 53%, 64%, and 67%, respectively, compared to spiral, gap, and labyrinth seals of the same seal width.

[0049] (Seal spacing h = 0.1 mm, pressure P = 0.2 MPa, speed N = 10000 rpm, seal level Z = 12, seal width B = 34 mm)

[0050] Seal type leakage (m 3 / h) Relative change range: spiral seal 10.5253% gap seal 13.7764% labyrinth seal 14.6967% self-impact seal 4.91-

[0051] Table 2 shows the standard leakage (Q = 0.4 m 3 / h) under the self-impact seal critical sealing distance, it can be seen that the fewer the stages, the smaller the critical distance when achieving standard leakage. When the stages are Z=6, 10, and 14, the corresponding critical distances are h o =32, 34, 37 μm, which is much higher than the normalized gas film condition of dry gas seal (2-5 μm). This advantage can greatly reduce the contact probability of the sealing pair, which is of great significance to improving the sealing stability!

[0052] Table 2 Critical sealing distance h of self-impact seal under standard leakage o

[0053] (Pressure P=0.2MPa, Speed ​​N=18000rpm, Medium: Air)

[0054] Sealing level critical sealing distance (μm) Z=632Z=1034Z=1437

[0055] The present invention also studies and analyzes four stacked structural schemes. As shown in Figure 11(a)-(d), taking a 10-stage seal as an example, the static ring and dynamic ring part unit structure types are defined as A(a) and B(b), respectively, where A and B indicate the presence of a wing-shaped structure at the bottom, and a and b indicate the absence of a wing-shaped structure at the bottom. Accordingly, the structural schemes in Figure 11(a)-(d) are AbbA, AbBa, aBBa, and aBbA, respectively. This definition and classification method is suitable for various sealing levels. As shown in Figure 11(e)-(h), the 4-, 6-, 8-, and 10-stage sealing structures corresponding to the AbbA type scheme are respectively shown. It can be seen that the bottom structure of the seal is the same for the same scheme, the top structure is also the same when the level difference is 4, and the top structure is different when the level difference is 2.

[0056] Leakage analysis was performed on four schemes under different sealing levels (Z = 4, 6, 8, 10) respectively, and the calculation results are shown in Table 3. It can be seen that when the level interval is 4 levels (4th and 8th levels, 6th and 10th levels), the leakage performance of each scheme is the same. The specific performance is as follows: when the levels are 4th and 8th levels, the order of each scheme according to the leakage size is AbBa < aBBa < aBbA < AbbA; when the levels are 6th and 10th levels, the order of each scheme according to the leakage size is AbBa < aBBa < AbbA < aBbA. It can be seen that although the overall leakage ranking of each scheme at different levels is not exactly the same, the leakage of the scheme AbBa is the smallest. The reason may be that there is a process in which the oncoming flow is directly blocked and then diverted in the stacked arrangement on both sides of this scheme (see Figure 11(b)). In this form, the energy dissipation efficiency is relatively high. Based on this, it can be considered that the scheme AbBa is the optimal leakage suppression structure scheme.

[0057] Table 3 Comparison of Leakage of Four Schemes under Different Levels

[0058] AbbAAbBaaBBaaBbAZ=455.0551.2552.3953.81Z=647.5641.5746.6656.16Z=845.0140.6341.6644.99Z=1040.7236.7739.8145.15

[0059] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A non-contact self-impact seal with high throttling efficiency and fixed clearance, characterized by: The non-contact self-impact seal is composed of a stationary ring, a dynamic ring, and a suspension column. The stationary ring, dynamic ring, and suspension column are all rigidly fixed. The suspension column is placed in the stationary ring or dynamic ring according to the assembly relationship. The non-contact gap formed by the rigid fixation of the stationary ring, dynamic ring, and suspension column constitutes a fluid channel. The fluid channel consists of an inlet, an outlet, and a stacked structure. The stacked structure is composed of several self-impact units. The self-impact units specifically include a fluid channel. The first bifurcation of the fluid channel branches into an oblique channel and a curved channel. The curved channel, after a sharp turn, intersects with the oblique channel again to form a second bifurcation. The arrangement of the self-impact unit can be composed of one or more combinations of symmetry, positive staggering, and negative staggering according to the arrangement relationship between the adjacent first bifurcation and the second bifurcation; positive staggering and a staggering ratio k=2 are the optimal solution, which can achieve the lowest leakage and will not make the sealing series unit too wide. Among them, the staggering value represents the specific position of the fluid channel, positive staggering is conducive to improving the leakage suppression effect, and the sealing leakage is the largest when negative staggering is used. The staggering ratio is a dimensionless characterization value that measures the positive and negative staggering amount of the series unit.

2. The non-contact self-impact seal with high throttling efficiency and fixed clearance according to claim 1, characterized in that: The stacked arrangement structure is specifically formed by a series combination of several self-impact units, and the series combination includes a single-row or multi-row arrangement style.

3. The non-contact self-impact seal with high throttling efficiency and fixed gap according to claim 2, characterized in that: The multi-row arrangement is to design the static ring into two parts that can be connected by bolts or interference fit, and the middle is sealed with a sealing ring. The suspension columns are placed in the corresponding static and dynamic rings respectively. The entire assembly can be completed in sequence in axial order. In the multi-row arrangement, the static ring and the dynamic ring are further split and then connected in series as a whole.

4. The non-contact self-impact seal with high throttling efficiency and fixed gap according to claim 2, characterized in that: During assembly, the dynamic ring is rigidly fixed to the shaft or sleeve by means of set screws, keys or interference fit connections, and the static ring is rigidly connected to the gland or body by means of anti-rotation pins, keys or interference fit connections.

5. The non-contact self-impact seal with high throttling efficiency and fixed gap according to claim 3, characterized in that: The static ring and the dynamic ring can be installed on the shaft or sleeve in axial order in a single-row or multi-row structural arrangement. The seal can also be assembled as a whole and then directly installed on the shaft or sleeve.