Self-draining reinforced pressurized dry gas seal structure

Abstract

The application provides a self-draining reinforced pressurized dry gas seal structure, which comprises a dynamic ring body, a static ring mechanism and an elastic supporting mechanism, the dynamic ring body is used for being installed on a rotating mechanism, the elastic supporting mechanism is used for being installed in a pump body, the static ring mechanism is installed on the pump body through the elastic supporting mechanism, the dynamic ring body is provided with a spiral group groove, the rotating mechanism is provided with a spiral groove used for being matched with the spiral group groove, the spiral group groove comprises an outer spiral groove and an inner spiral groove which are sequentially arranged from outside to inside along the radial direction of the dynamic ring body, and the spiral direction of the inner spiral groove is opposite to that of the outer spiral groove, and the application can solve the problem that a set of compressed air source introduction sealing gas blocking medium needs to be specially equipped in the prior art, the application is not suitable for the equipment with compact structure and limited equipment space, and the air inlet design of the equipment cannot be met.

Description

Technical Field

[0001] This invention relates to the field of dry gas sealing technology, specifically to a self-draining enhanced pressurized dry gas sealing structure. Background Technology

[0002] High-speed pumps, as a special type of centrifugal pump, have shown broad application prospects in many industrial fields due to their advantages such as high speed, high head, and compact structure. In the aerospace field, the pressurization and transportation of liquid oxygen / kerosene propellants needs to meet the cleanliness requirements of 10^-6. The precision control capabilities of high-speed pumps meet this requirement, therefore, the sealing performance requirements of mechanical seals used in high-speed pumps are extremely high.

[0003] High-speed pump dry gas seal is a non-contact shaft end sealing technology applied to high-speed rotating equipment (such as centrifugal pumps). Its core principle is to form a micron-level gas film on the sealing end face through the gas dynamic pressure effect, achieving a zero-leakage or zero-escape sealing effect. For example, the invention disclosed in CN110985433B discloses an adjustable dynamic seal device and turbine pump assembly for turbine pumps (hereinafter referred to as prior art 1), including a dynamic ring, a stationary ring assembly, an axial force loader, and a housing. The stationary ring assembly includes a stationary ring, a stationary ring seat, a stationary ring bellows, and a rear seat connected in sequence, wherein the stationary ring is used to abut against the dynamic ring, and the rear seat is used to fix and connect the housing. The stationary ring seat is connected to the stationary ring bellows on its radially inner side and to one end of the axial force loader on its radially outer side, and the other end of the axial force loader is connected to the housing. The housing is also provided with a pressure tapping hole corresponding to the axial force loader at the connection position. The air source applies pressure to the axial force loader through the pressure tapping hole, and the force is transmitted to the stationary ring and the moving ring through the stationary ring seat to adjust the end face mating force of the stationary ring and the moving ring.

[0004] In the prior art 1, sealing gas can be introduced through an air source to block the medium, but a special compressed air source needs to be equipped. The configuration of the compressed air source inevitably makes the overall configuration of the dry gas sealing device more complicated, making the entire operating system more complicated and reducing its effectiveness. It is not suitable for equipment with a compact structure, limited equipment space, and inability to meet the design requirements of the air inlet. Summary of the Invention

[0005] The purpose of this invention is to provide a self-draining enhanced pressurized dry gas sealing structure, which can solve the problem in practical use that the existing technology requires a special set of compressed air source to introduce the sealing gas barrier medium, which is not suitable for equipment with compact structure and limited space that cannot meet the design requirements of the air inlet.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A self-draining enhanced pressurized dry gas sealing structure, characterized in that it includes a dynamic ring body, a static ring mechanism and an elastic support mechanism, wherein the dynamic ring body is used to be mounted on a rotating mechanism;

[0008] The elastic support mechanism is used to be installed in the pump body, and the stationary ring mechanism is installed on the pump body through the elastic support mechanism; the moving ring body is provided with a spiral groove, and the rotating mechanism is provided with a spiral groove for cooperating with the spiral groove.

[0009] The spiral groove assembly includes an outer spiral groove and an inner spiral groove arranged sequentially from the outside to the inside along the radial direction of the moving ring body.

[0010] Preferably, the rotating mechanism includes a rotating shaft and a bushing, the bushing being fixedly mounted on the rotating shaft, and the rotating ring body being connected to the bushing.

[0011] Preferably, the bushing is provided with a first mounting groove, and a first sealing ring is installed in the first mounting groove.

[0012] Preferably, the inner and outer spiral grooves are arranged alternately.

[0013] Preferably, the stationary ring mechanism includes a stationary ring body and a push ring, the stationary ring body is fixedly mounted on the push ring, and the push ring is connected to the elastic support mechanism.

[0014] Preferably, the elastic support mechanism includes a spring body and a spring seat, the spring seat is fixedly installed in the pump body, and the push ring is connected to the spring seat through the spring body.

[0015] Preferably, a retaining ring is fixedly installed inside the pump body, and a limiting area for limiting the stationary ring body is formed between the retaining ring and the pump body.

[0016] Preferably, the retaining ring is provided with a second mounting groove, and a second sealing ring is installed in the second mounting groove.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In this invention, when the rotating ring body rotates at high speed along the shaft, the outer spiral groove generates centrifugal and shear forces due to its spiral structure, drawing ambient air from the outside of the sealing end face into the outer spiral groove. As the gas flows along the spiral groove towards the center of the rotating ring body, the depth of the outer spiral groove gradually decreases, and the gas is compressed to form a high-pressure gas film. This gas film establishes a stable non-contact isolation layer between the stationary ring and the rotating ring body, effectively preventing media leakage.

[0019] The inner spiral groove has a spiral direction opposite to that of the outer spiral groove, which can generate a reverse pumping effect on the medium. When a small amount of medium attempts to leak outward through the sealing end, the inner spiral groove, which rotates with the rotating mechanism, can push the medium along the groove into the pump body, forming a backflow effect, thereby reducing the amount of medium leakage and improving the sealing resistance. The outer spiral groove is responsible for air intake and pressurization, while the inner spiral groove is responsible for medium backflow. The two are radially distributed to form functional zones, jointly constructing a sealing system that does not require an external air source. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of the moving ring body in this invention.

[0023] The attached diagram lists the components represented by each number as follows:

[0024] 101-Dynamic ring body, 102-Static ring mechanism, 103-Elastic support mechanism, 104-Rotation mechanism, 105-Pump body, 106-Helical groove, 107-Helical groove, 108-Outer spiral groove, 109-Inner spiral groove, 110-Rotation shaft, 111-Shaft sleeve, 112-First sealing ring, 113-Static ring body, 114-Push ring, 115-Spring body, 116-Spring seat, 117-Snap ring, 118-Second sealing ring, 119-Third sealing ring. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0026] In the description of the embodiments of the present invention, it should be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0029] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of the present invention; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0031] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] Example 1

[0033] See Figures 1-2 This embodiment discloses a self-draining enhanced pressurized dry gas sealing structure, including a dynamic ring body 101, a stationary ring mechanism 102 and an elastic support mechanism 103. The dynamic ring body 101 is used to be installed on the rotating mechanism 104.

[0034] The elastic support mechanism 103 is used to be installed inside the pump body 105, and the stationary ring mechanism 102 is installed on the pump body 105 through the elastic support mechanism 103; the moving ring body 101 is provided with a spiral groove 106, and the rotating mechanism 104 is provided with a spiral groove 107 for cooperating with the spiral groove 106.

[0035] The spiral groove 106 includes an outer spiral groove 108 and an inner spiral groove 109 arranged radially from the outside to the inside along the moving ring body 101. The spiral direction of the inner spiral groove 109 is opposite to that of the outer spiral groove 108.

[0036] In this embodiment, the end face opposite to the stationary ring mechanism 102 of the rotating ring body 101 is a sealing end face. The spiral groove 106 is disposed on the sealing end face. The spiral groove 106 includes an outer spiral groove 108 and an inner spiral groove 109 arranged radially from the outside to the inside. The rotating mechanism 104 is provided with a spiral groove 107, which is disposed on the outer circumferential surface near the rotating ring body 101. The spiral line of the spiral groove 107 is axially aligned with the spiral line of the inner spiral groove 109 of the rotating ring to ensure the formation of a continuous flow channel and avoid abrupt changes in the flow channel. The spiral groove 107 and the inner spiral groove 109 disposed on the rotating ring body 101 form a continuous flow channel in the axial direction, which together enhances the reverse pumping and throttling effect of the medium. Moreover, when the rotating mechanism 104 is started or in the low-speed operation stage, the dynamic pressure effect is weak. The spiral groove 107 disposed on the rotating mechanism 104 can produce a significant reverse guiding effect on the medium at low speed, which better matches the initial closing force provided by the elastic support mechanism 103. The outer spiral groove 108 extends from the outer edge of the sealing end face towards the center, while the inner spiral groove 109 extends from the medium side, and the spiral direction of the inner spiral groove 109 is opposite to that of the outer spiral groove 108. When the rotating mechanism 104 rotates at high speed, it drives the rotating ring body 101 to rotate. When the rotating ring body 101 rotates at high speed with the shaft, the outer spiral groove 108 generates centrifugal force and shear force within the groove due to its spiral structure, drawing ambient air from the outside of the sealing end face into the outer spiral groove 108. As the gas flows along the spiral groove 107 towards the center of the rotating ring body 101, the groove depth of the outer spiral groove 108 gradually becomes shallower, and the gas is compressed to form a high-pressure gas film. This gas film establishes a stable non-contact isolation layer between the stationary ring and the rotating ring body 101, effectively preventing medium leakage. The spiral direction of the inner spiral groove 109 is opposite to that of the outer spiral groove 108, enabling a reverse pumping effect on the medium. When a small amount of medium attempts to leak outward through the sealing end, the inner swirling groove 109, which rotates with the rotating mechanism 104, can push the medium along the groove into the pump body 105, forming a backflow effect, thereby reducing the amount of medium leakage and improving the sealing resistance. The outer swirling groove 108 is responsible for air intake and pressurization, while the inner swirling groove 109 is responsible for medium backflow. The two form functional zones in radial distribution, jointly constructing a sealing system that does not require an external air source. Through the coordinated work of the inner swirling groove 109 and the outer swirling groove 108, ambient air is directly used as the sealing air source, which not only forms a stable gas film to isolate the medium, but also actively suppresses medium leakage. It does not require an external compressed air or nitrogen system and is suitable for compact equipment with limited space and where it is impossible to set an external air source interface, thus expanding the application scenarios of dry gas sealing.

[0037] The outer spiral groove 108 is a spiral groove 107 extending from the outer edge of the sealing end face towards the center, with its depth decreasing linearly from the outer edge to the center along the groove line; the inner spiral groove 109 is a spiral groove 107 extending from the medium side towards the middle of the sealing end face, with its spiral direction opposite to that of the outer spiral groove 108, and its depth decreasing linearly from the inner edge to the center along the groove line; the initial groove depth of the outer spiral groove 108 is defined as h at the outer edge. o1 The depth of the termination groove is h, located at the junction with the inner spiral groove 109. o2 The initial groove depth of the inner swirling groove 109 is defined as h, located at the inner edge of the medium side. i1 The depth of the termination groove is h at the junction with the outer spiral groove 108. i2 ;

[0038] The groove depths of the inner spiral groove 109 and the outer spiral groove 108 satisfy the following cooperative relationship:

[0039] and

[0040] By making The value between 1.5 and 2.5 ensures that the initial section of the outer swirl groove 108 has a stronger gas intake capacity, while avoiding insufficient medium reflux due to an overly shallow inner swirl groove 109; The depth gradient of the outer swirl channel 108 is maintained between 0.3 and 0.6 to ensure a suitable decreasing gradient, allowing the gas to gradually increase in pressure during flow; A depth between 0.4 and 0.8 allows the inner swirl channel 109 to maintain its reflux capacity while preventing the medium from becoming stuck due to excessive channel depth.

[0041] The helix angle θ of the outer spiral groove 108 o The helix angle θ of the inner spiral groove 109 i satisfy:

[0042] 20°≥θ o -θ i ≥10°, and 15°≤θ i <θ o ≤40°

[0043] The helix angle θ of the outer spiral groove 108 o A larger θ value is beneficial for gas intake and pressurization; the inner vortex groove 109... i A smaller helix angle value is beneficial for reverse pumping of the medium; when the θ o and θ i When the difference is between 10° and 20°, functional zoning and flow field coordination can be achieved.

[0044] The width of the outer spiral groove 108 is W. O The width of the inner spiral groove 109 is W. iThe two satisfy the slot width coordination formula:

[0045]

[0046] The outer swirling groove 108 has a wider groove than the inner swirling groove 109, which is beneficial for gas flow. The narrower groove width of the inner swirling groove 109 is beneficial for increasing the thrust of medium recirculation. Between 1.1 and 1.8, eddies or pressure losses caused by abrupt changes in the flow channel can be avoided. In this embodiment, the synergistic relationship between the groove depth, helix angle, and groove width is optimized based on computational fluid dynamics simulation and bench test data for high-speed pump sealing conditions. Its purpose is to balance the air induced pressure boosting capacity of the outer swirling groove 108 with the medium return capacity of the inner swirling groove 109, and avoid a surge in eddies or pressure losses due to improper flow channel matching.

[0047] In this embodiment, for the commonly used sealing end face specifications of high-speed pumps, the outer radius Ro = 20-50mm and the inner radius Ri = 10-30mm, the preferred external vortex groove 108 has an initial groove depth h. o1 =8-15μm, final trench depth h o2 =3-8μm; Inner swirl groove 109, initial groove depth h i1 = 4-10μm, final trench depth h i2 =2-6μm; External spiral groove 108 groove width W O =1.5-3mm, inner spiral groove 109 groove width W i =1-2mm; the groove cross-section of the inner and outer spiral grooves is rectangular, the verticality of the groove wall is ≤0.01mm / m, and the groove spacing is 1-1.5 times the groove width. In this embodiment, the groove spacing of the inner and outer spiral grooves is 1.25 times the groove width.

[0048] Further optimization involves the rotation mechanism 104, which includes a rotation shaft 110 and a bushing 111. The bushing 111 is fixedly mounted on the rotation shaft 110, and the moving ring body 101 is connected to the bushing 111. In this embodiment, the bushing 111 is coaxially fixedly fitted onto the rotation shaft 110, and the spiral groove 107 is disposed on the bushing 111. The spiral groove 107 and the spiral groove 106 of the moving ring form a continuous gas flow channel. When the bushing 111 rotates at high speed with the rotation shaft 110, the spiral groove 107 further enhances the gas diversion effect from axial to radial, improves the efficiency of gas entering the moving ring channel, and enhances the stability of gas film formation.

[0049] Further optimization involves providing a first mounting groove on the bushing 111, within which a first sealing ring 112 is installed. In this embodiment, the first sealing ring 112 is made of an elastic material such as fluororubber or polytetrafluoroethylene. The first sealing ring 112 is installed in the annular groove of the bushing 111, and under axial clamping force, it fits tightly against the shaft surface, forming a static sealing barrier to prevent media leakage along the axial gap.

[0050] Further optimization involves an alternating arrangement of the inner swirl groove 109 and the outer swirl groove 108. When the dynamic ring body 101 rotates at high speed, the alternating structure formed by the inner swirl groove 109 and the outer swirl groove 108 creates a multi-stage compression unit on the sealing end face. The gas undergoes primary compression in the outer swirl groove 108. After entering the alternating region, some of the gas flow is guided to the near-root region of the inner swirl groove 109, close to the inner side of the sealing surface, where it undergoes secondary compression. This makes the gas film pressure distribution on the sealing end face more uniform, with higher rigidity and stronger anti-interference capability. The alternating arrangement of the inner swirl groove 109 and the outer swirl groove 108 makes the dynamic pressure distribution on the sealing end face more continuous, and the gas film forms a smooth pressure transition zone in the radial direction, significantly improving the uniformity of gas film load and operational stability. Furthermore, because the inner swirl groove 109 and the outer swirl groove 108 are alternately distributed, when the medium attempts to leak outward, it will be simultaneously pushed by the backflow of multiple inner swirl grooves 109, forming a more coherent and stronger medium blocking effect.

[0051] In a further optimization, the stationary ring mechanism 102 includes a stationary ring body 113 and a push ring 114. The stationary ring body 113 is fixedly mounted on the push ring 114, and the push ring 114 is connected to the elastic support mechanism 103. In this embodiment, the axial pressure provided by the elastic support mechanism 103 is continuously and stably applied to the stationary ring body 113 through the push ring 114, ensuring a moderate fit between it and the end face of the moving ring. A stable sealing gap can be maintained by using the spring.

[0052] Further optimization involves the elastic support mechanism 103, which includes a spring body 115 and a spring seat 116. The spring seat 116 is fixedly installed inside the pump body 105, and the push ring 114 is connected to the spring seat 116 via the spring body 115. The spring seat 116 is mounted on the pump body 105, and the stationary ring body 113 is connected to the spring seat 116 via the spring body 115. Before the pump body 105 starts, the preload of the spring body 115 is applied to the sealing end face through the spring seat 116 and the stationary ring body 113, forming an initial closing force. During the start-up, shutdown, acceleration, and deceleration of the pump body 105, the rotating shaft 110 will experience axial movement due to changes in temperature and force. The force provided by the spring body 115 can be used to compensate for the axial displacement caused by this movement.

[0053] Further optimization involves a retaining ring 117 fixedly installed inside the pump body 105, forming a limiting area between the retaining ring 117 and the pump body 105 for limiting the stationary ring body 113. In this embodiment, the retaining ring 117 is threadedly connected to the inner wall of the pump body 105, forming an axial limiting structure with the pump body 105 to prevent axial displacement or detachment of the stationary ring body 113 under the action of high-pressure medium, ensuring the alignment and stability of the sealing surface.

[0054] Further optimization involves providing a second mounting groove on the retaining ring 117, within which a second sealing ring 118 is installed. The second sealing ring 118 is installed within the annular groove between the retaining ring 117 and the pump body 105, forming a radial static seal. The second sealing ring 118 prevents leakage of the medium from the assembly gap between the static ring and the pump body 105.

[0055] Further optimization involves providing a third mounting groove on the spring seat 116, within which a third sealing ring 119 is installed. Under axial clamping force, the third sealing ring 119 undergoes elastic deformation, sealing the gap between the spring seat 116 and the stationary ring body 113. This effectively isolates the process medium leaking axially from the inner side of the sealing end face (i.e., the medium side) from directly impacting, penetrating, and eroding the spring seat 116 and spring body 115, ensuring the stability of the elastic support mechanism 103 and guaranteeing the quality of the gas film formation.

[0056] Example 2

[0057] See Figures 1-2 This embodiment, based on the sealing structure described in Embodiment 1, integrates a condition monitoring and early warning system to assess the sealing health status and issue an alarm when there is a potential risk.

[0058] The status monitoring and early warning system includes a pressure sensor, a speed sensor, a processor unit, and an early warning device. The pressure sensor is a pressure transmitter suitable for pumping media, and its probe is installed in the media cavity through a reserved process interface on the pump body 105 for real-time monitoring of the pressure P of the sealed medium. m The speed sensor can be a magnetoelectric or photoelectric sensor, used to align with the speed measuring gear or grating mounted on the rotating shaft 110 or bushing 111, for monitoring the real-time speed n of the rotating shaft 110. currentThe processor unit is equipped with a signal acquisition module, which connects to the pressure sensor and speed sensor via wired cable, industrial bus, or wireless means. This module receives the analog signal from the pressure sensor and the pulse signal from the speed sensor, filters, amplifies, and converts the signal to digital before transmitting it to the processor unit. The processor unit is an embedded system with computing and logic control capabilities, such as a PLC, industrial microcontroller, or industrial computer, and is located in the equipment control cabinet or remote monitoring room. It connects to the signal acquisition module via cable or industrial bus such as RS485 or PROFIBUS to receive digitized pulse signals. m and n current The processor unit has pre-stored sealed structure parameters for calculation; the early warning device includes an audible and visual alarm such as a buzzer, an alarm light, and a human-machine interface (HMI). The early warning device is connected to the output port of the processor unit via a wired cable, industrial bus, or wireless means, and is used to issue audible, visual, or text alarm information according to the instructions issued by the processor unit.

[0059] The operation method of the status monitoring and early warning system is as follows:

[0060] S1. Calculate the sealing stability number S;

[0061] The sealing stability number S represents the ability of the gas film between the sealing end faces to resist medium pressure interference and maintain a stable non-contact state under specific operating conditions. Its calculation method is based on the balance relationship between the outer swirl groove 108, the inner swirl groove 109, the generated gas film stiffness, and the medium pressure, as detailed below:

[0062]

[0063] Wherein, p m For monitorable operating parameters, P represents the pressure of the sealed medium. m The unit is MPa; the K g The dynamic pressure stiffness of the gas film between the sealed end faces is measured in MPa / μm, representing the gas film's ability to resist pressure changes and maintain thickness stability. Its value is determined by the seal's structural parameters and operating speed.

[0064] The K g The calculation method is as follows:

[0065]

[0066] Wherein, n is the operating speed of the rotating shaft 110 in rpm, and is a controllable operating parameter; μ is the dynamic viscosity of the gas in the sealed gas film in Pa·s, and is a known physical property constant for common gases such as air; R0 and R iThe outer and inner radii of the sealing end face refer to the distances from the outer and inner edges of the annular working surfaces of the moving ring body 101 and the stationary ring body 113, respectively, to the axis of rotation; the h o The target gas film thickness (in meters) for the sealing end face is preset to an optimized design value based on friction, wear, and leakage requirements. The h... 01 and h i1 The initial groove depth of the outer spiral groove 108 and the inner spiral groove 109 is in meters; the θ o and θ i The helix angles of the outer spiral groove 108 and the inner spiral groove 109 are given; C is a constant that can be determined in one go through conventional hydrodynamic lubrication numerical calculations or performance tests on standard samples.

[0067] S2. Determine the state of the sealing end face based on the sealing stability number S;

[0068] For equipment such as high-speed pumps, the pressure P of the sealed medium m This may vary depending on the process flow. To ensure the sealing effect of the gas film generated at the sealing end face, the following steps are taken to adaptively adjust the rotation speed based on the sealing stability coefficient:

[0069] S21. Set target threshold: Based on safety margin and long-term operating experience, set a minimum allowable sealing stability number S for the sealing structure. target ;

[0070] Based on the operating range of the high-speed pump (speed 3000-15000 rpm, medium pressure 0.1-5 MPa), the minimum allowable sealing stability coefficient S is set. target =1.5-3.0, where under low-pressure conditions Pm≤1MPa, Starget=1.5-2.0, and under high-pressure conditions Pm>1MPa, S target =2.0-3.0;

[0071] S22. Operating Condition Monitoring and Judgment: Real-time or periodic monitoring of medium pressure P m ;

[0072] S23, Warning: Adjust the current rotational speed n current and the detected medium pressure P m Substitute into the calculation of the current sealing stability number S current ;

[0073] If S current ≥S target This indicates that the sealing stability is sufficient under the current operating conditions, and no warning is required;

[0074] If S current Less than S targetThis indicates that increased medium pressure or other factors have led to a decrease in seal stability, posing a risk of leakage. In this case, the processor unit determines that the current seal stability is below the safety threshold, triggering an alarm to prompt operators to check the operating conditions or seal status.

[0075] The target rotational speed n target The calculation method is as follows:

[0076]

[0077] When an increase in medium pressure is detected, the early warning device issues an alarm, and the processor unit calculates the target rotational speed n. target And it is displayed via a human-machine interface connected to the processor unit; the operator can adjust the target rotation speed n as displayed. target Adjust the rotating shaft 110 to the required safe speed to ensure that the S value is always not lower than the target threshold, thereby actively maintaining the stability of the gas film and the reliability of the seal under various fluctuating working conditions; solve the problem that the performance of traditional dry gas seals may decline when working conditions change, and realize intelligent sealing protection.

[0078] Example 3

[0079] See Figures 1-2 This embodiment is based on implementation 2, and further optimizes the calculation method of the sealing stability number S according to the structure of the spiral groove 107 set on the bushing 111. In this embodiment, the spiral groove 107 is set on the outer circumferential surface of the bushing 111, and its spiral direction is the same as the spiral direction of the inner spiral groove 109 set on the moving ring body 101. This makes the spiral groove 107 on the bushing 111 and the inner spiral groove 109 on the moving ring body 101 form a continuous and consistent fluid dynamic channel in the axial direction, which works together on the medium side region. The spiral groove 107 and the inner spiral groove 109 cooperate to further increase the reverse pumping and throttling pressure reduction effect.

[0080] The helix angle of the spiral groove 107 is θ. s The groove depth is f s The slot width is Ws, where:

[0081]

[0082] Since the spiral groove 107 and the inner spiral groove 109 have the same spiral direction, when the bushing 111 rotates at high speed with the rotating shaft 110, they form a continuous spiral pumping channel in the axial projection. When the medium attempts to leak outward along the axial direction, it is first captured by the spiral groove 107 on the bushing 111 and pumped into the pump body 105, and then guided into the inner spiral groove 109 of the moving ring, realizing two-stage reverse pumping. This continuity greatly enhances the effect of medium reflux and significantly reduces the net leakage. The groove depth h of the spiral groove 107 s The initial depth h of the inner spiral groove is greater than or equal to 109. i1 This allows the spiral groove 107 and the inner spiral groove 109 to form a gradually narrowing flow channel cross-section from the bushing 111 to the moving ring body 101. As the medium flows through this path, the flow resistance gradually increases, and kinetic energy is gradually converted into pressure energy, achieving effective throttling and stepwise pressure reduction of the medium. This avoids high-pressure, high-particle-content media directly impacting the sealing end face; the aforementioned parameter synergy ensures that the spiral groove 107 and the inner spiral groove 109 are matched in geometry and dynamic characteristics. A suitable helix angle ratio ensures a smooth streamline transition; a suitable depth-to-width ratio coordinates the flow channel capacity and resistance, achieving a balance between reverse pumping efficiency and throttling effect.

[0083] In this embodiment, the K g The calculation method is as follows:

[0084]

[0085] μ is the dynamic viscosity of the gas in the sealed gas film, in Pa·s, and is a known physical property constant for common gases such as air. n is the operating speed of the rotating shaft 110, in rpm.

[0086] The Γ parameter is the contribution parameter of the spiral groove 107 of the bushing 111. The calculation method is as follows:

[0087]

[0088] Wherein, the θ s The helix angle of the spiral groove 107 on the outer circumference of the bushing 111 is in radians, and the h s The groove depth of the spiral groove 107 on the bushing 111 is in meters (m). η is the radial flow channel coupling efficiency coefficient, with a value range of 0 < η ≤ 1. This coefficient describes the efficiency of the hydrodynamic connection between the spiral groove 107 on the bushing 111 and the inner spiral groove 109 on the moving ring body 101. Its value can be obtained through a single calibration using CFD simulation or bench testing. When the bushing 111 does not have a spiral groove 107, Γ = 1.

[0089] In this example, K is calculated by introducing the contribution parameter Γ of the spiral groove 107 of the bushing 111.g This allows the calculated sealing stability number S to more accurately and reliably reflect the actual sealing capability of the dry gas sealing structure of the present invention.

[0090] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-draining, enhanced, pressurized dry gas sealing structure, characterized in that: It includes a rotating ring body (101), a stationary ring mechanism (102), and an elastic support mechanism (103), wherein the rotating ring body (101) is used to be mounted on the rotating mechanism (104); The elastic support mechanism (103) is used to be installed inside the pump body (105), and the stationary ring mechanism (102) is installed on the pump body (105) through the elastic support mechanism (103); the moving ring body (101) is provided with a spiral groove (106), and the rotating mechanism (104) is provided with a spiral groove (107) for cooperating with the spiral groove (106). The spiral groove (106) includes an outer spiral groove (108) and an inner spiral groove (109) arranged in sequence from the outside to the inside along the radial direction of the moving ring body (101). The spiral direction of the inner spiral groove (109) is opposite to that of the outer spiral groove (108). The spiral groove (107) is disposed on the outer peripheral surface near the moving ring body (101). The spiral line of the spiral groove (107) is axially aligned with the spiral line of the inner spiral groove (109) of the moving ring. The spiral groove (107) and the inner spiral groove (109) disposed on the moving ring body (101) form a continuous flow channel in the axial direction. The spiral direction of the outer spiral groove 108 extends from the outer edge of the sealing end face to the center, and its groove depth decreases linearly from the outer edge to the center along the groove line; the spiral direction of the inner spiral groove (109) extends from the medium side to the middle of the sealing end face, and its groove depth decreases linearly from the inner edge to the middle along the groove line. The initial groove depth of the outer spiral groove (108) is defined as being located at the outer edge. The depth of the termination groove is located at the junction with the inner spiral groove (109). The initial groove depth of the inner swirling groove (109) is defined as the inner edge of the medium side. The depth of the termination groove is located at the junction with the outer spiral groove (108). The groove depths of the inner spiral groove (109) and the outer spiral groove (108) satisfy the following cooperative relationship: 。 2. The self-draining enhanced pressurization dry gas sealing structure according to claim 1, characterized in that: The rotating mechanism (104) includes a rotating shaft (110) and a bushing (111). The bushing (111) is fixedly installed on the rotating shaft (110), and the rotating ring body (101) is connected to the bushing (111).

3. The self-draining enhanced pressurization dry gas sealing structure according to claim 2, characterized in that: The bushing (111) is provided with a first mounting groove, and a first sealing ring (112) is installed in the first mounting groove.

4. The self-draining enhanced pressurization dry gas sealing structure according to claim 1, characterized in that: The inner spiral groove (109) and the outer spiral groove (108) are arranged alternately.

5. The self-draining enhanced pressurization dry gas sealing structure according to claim 1, characterized in that: The stationary ring mechanism (102) includes a stationary ring body (113) and a push ring (114). The stationary ring body (113) is fixedly mounted on the push ring (114), and the push ring (114) is connected to the elastic support mechanism (103).

6. The self-draining enhanced pressurization dry gas sealing structure according to claim 5, characterized in that: The elastic support mechanism (103) includes a spring body (115) and a spring seat (116). The spring seat (116) is fixedly installed inside the pump body (105), and the push ring (114) is connected to the spring seat (116) through the spring body (115).

7. The self-draining enhanced pressurization dry gas sealing structure according to claim 5, characterized in that: A retaining ring (117) is fixedly installed inside the pump body (105), and a limiting area is formed between the retaining ring (117) and the pump body (105) for limiting the stationary ring body (113).

8. The self-draining enhanced pressurization dry gas sealing structure according to claim 7, characterized in that: The retaining ring (117) is provided with a second mounting groove, and a second sealing ring (118) is installed in the second mounting groove.

9. A self-draining enhanced pressurized dry gas sealing structure according to claim 6, characterized in that: The spring seat (116) is provided with a third mounting groove, and a third sealing ring (119) is installed in the third mounting groove.

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