A non-contact hydraulic sealing device based on helical groove fluid dynamic effect

Abstract

This invention discloses a non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves, aiming to solve the problem of dry friction damage between the spiral groove surface and the smooth surface of the stationary ring during the start-up and shutdown phases of pump equipment. The device includes a rotating ring, a stationary ring, a secondary ring, and a locking mechanism. During initial startup, the secondary ring rotates under the viscous shear force of the rotating ring, effectively transferring mechanical friction to a preset wear-resistant surface, protecting the core spiral groove from high temperature and wear. When the rotational speed reaches a preset threshold, the locking mechanism is hydraulically or electromagnetically driven, braking through a piston and locking block, causing the secondary ring to transition from a rotating state to a stationary locked state. At this time, a momentary speed jump occurs between the rotating ring and the secondary ring, guiding the spiral groove to quickly establish a high-rigidity liquid film, achieving stable and reliable non-contact operation. This invention, by introducing a secondary ring and coordinating with locking and braking control, achieves friction transfer, protects the core working surface, and achieves a protective effect on the core hydraulic sealing structure.

Description

Technical Field

[0001] This invention relates to the field of pump sealing technology, and specifically to a non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves. Background Technology

[0002] In high-speed, high-pressure pumps such as boiler feed pumps, sealing technology is crucial to the reliability and lifespan of the equipment. Traditional contact mechanical seals suffer from severe end-face wear, making it difficult to meet the requirements for long-term stable operation. Therefore, contactless sealing technology based on the hydrodynamic effect of spiral grooves has emerged as one of the core technologies for solving the seal wear problem in this field. Its working principle typically involves machining micron-sized spiral grooves on the sealing end faces of the rotating or stationary rings. When the pump shaft rotates, the spiral grooves pump fluid between the sealing end faces through shearing action, generating a hydrodynamic pressure rise. This pushes the rotating and stationary ring end faces apart, forming an extremely thin fluid film. This "hydrodynamic pressure balance" state achieves contactless operation between the end faces, significantly extending seal life and reducing power consumption.

[0003] Because the hydrodynamic conversion efficiency of a spiral groove is highly dependent on its micro-geometric topology (such as groove depth tolerance, groove width ratio, and surface roughness of the groove bottom), the end face is extremely difficult to machine and very expensive. The geometric profile of the spiral groove must maintain a high degree of integrity; depth deviation or wear of the groove edge radius will directly cause the flow field to change from stable laminar flow to turbulent flow, thereby significantly reducing the opening force.

[0004] During the pump's start-up and operation, as the pump shaft begins to rotate, the spiral grooves force external fluid into the space between the sealing end faces through shearing action. The fluid dynamic pressure gradually increases with the rotational speed until it is sufficient to overcome the back spring force and the fluid static pressure, thus opening the dynamic and stationary rings. However, in existing technologies, the spring preload on the stationary ring is usually constant and rigid, and during the transient process of pump start-up, there is a significant lag in the establishment of fluid dynamic pressure. Before the dynamic pressure reaches a threshold sufficient to open the sealing surface, the dynamic and stationary rings remain in forced contact under the high pressure of the elastic compensation mechanism. At this time, the high-speed rotation of the dynamic ring and the strong clamping of the stationary ring will generate severe dry friction, i.e., initiation dry friction.

[0005] This dry friction causes the temperature of the sealing surface to spike rapidly, easily leading to thermal cracking of the sealing material or thermal deformation of the end face. More seriously, dry friction directly damages the precise microscopic geometry of the spiral groove, resulting in a significant weakening of its hydrodynamic effect. This damage not only further increases the opening pressure threshold of the seal but also causes a continuous deterioration in sealing performance, thereby drastically shortening the service life of the seal and seriously threatening the operational reliability of pumps under high-frequency start-stop or complex operating conditions.

[0006] Therefore, existing technologies lack effective active intervention methods to address the end-face damage problem during the start-up and shutdown phases. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves, which aims to effectively solve the problem of dry friction between the dynamic and static rings during the start-up and shutdown phases and the resulting damage to the sealing end face structure in the prior art.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a non-contact hydraulic sealing device based on the hydrodynamic effect of a spiral groove, comprising a rotating ring, a stationary ring, a secondary ring, and a locking mechanism; the secondary ring is rotatably mounted on the stationary ring and forms a hydraulic sealing structure corresponding to the rotating ring; the locking mechanism is used to lock the secondary ring relative to the stationary ring.

[0009] Furthermore, the locking mechanism includes a locking block, a return spring, a locking rod, and a piston. The piston is disposed inside the plug cylinder and receives driving force. The locking rod is fixed to the bottom of the piston. The return spring is located between the plug cylinder and the piston and is fitted onto the locking rod. The locking block is fixed to the bottom of the locking rod and corresponds to the secondary ring.

[0010] Furthermore, the driving force is the water pressure introduced from the outlet of the pump body. The outlet of the pump body is provided with a water inlet, which is connected to the inlet of the plug cylinder in sequence via a shut-off valve, a filter, a pressure reducing valve, a check valve, an accumulator, and a pressure gauge.

[0011] Furthermore, it also includes a backflow mechanism, which includes a backflow head, a three-way valve, and a flow regulating valve. The three-way valve is connected between the filter and the pressure reducing valve, and its branch is connected to the flow regulating valve and the backflow head. The backflow head is correspondingly disposed in the pump body.

[0012] Furthermore, the driving force is the locking force provided by the electric lock plate, and the locking mechanism includes an electromagnetic component, a driving rod, and an electromagnetic lock plate; the electromagnetic component is installed on the pump housing, one end of the driving rod is connected to the piston, and the other end is provided with an electromagnetic lock plate corresponding to the electromagnetic component.

[0013] Furthermore, the moving ring is fixed on the moving ring seat at the end of the bushing, and a spiral groove is provided at the end of the moving ring.

[0014] Furthermore, the stationary ring adapter is fitted onto the stationary ring seat, and a first sealing ring is provided between the stationary ring and the stationary ring seat.

[0015] Furthermore, the secondary ring is connected to a locking sleeve via a spline structure, and the end of the locking sleeve is provided with an elastic deformation layer, with the outer side of the locking sleeve corresponding to the locking mechanism.

[0016] Furthermore, the moving ring is mounted on the bushing, and the stationary ring is mounted on the stationary ring seat via an elastic compensation mechanism. A rotating groove is provided at the outer end of the stationary ring, and a rotating seat is provided at the inner end of the secondary ring, with the rotating seat fitted inside the rotating groove.

[0017] Furthermore, the rotating seat includes multiple rotating blocks, which are assembled below the locking sleeve and fixed on the secondary ring. A washer is provided between the rotating seat and the locking sleeve, and a second sealing ring is provided between the rotating groove and the rotating seat.

[0018] The beneficial effects of the above technical solution are as follows: In response to the problem in the prior art that the dynamic and static rings inevitably generate severe dry friction during the start-up and shutdown phases due to the lag in the establishment of dynamic pressure, which leads to damage to the precision geometric profile of the spiral groove and sealing failure, this invention provides a solution that, by introducing a secondary ring intermediate body in conjunction with locking and braking control, achieves friction transfer, protects the core working surface, and upgrades the traditional dynamic and static two-body sealing structure into a dynamic, secondary, and static three-body collaborative system. Through physical isolation, the sealing logic is decomposed into independent functional surfaces and friction surfaces, thereby achieving protection of the core hydraulic sealing structure.

[0019] During implementation, in the initial transient phase of pump startup, the rotating fit structure between the bottom of the secondary ring and the rotating groove of the stationary ring is utilized to enable the secondary ring to rotate under the viscous shear force of the rotating ring. This causes the dry grinding during startup to occur on a pre-designed sacrificial wear-resistant surface made of a highly thermally conductive and self-lubricating material. This achieves spatial displacement of the dry grinding risk and ensures that the core functional surface of the rotating ring spiral groove is in a relatively static protective state before the dynamic pressure is established. This solves the problems of thermal cracking, deformation, and loss of geometric accuracy of the spiral groove caused by dry grinding in existing technologies, and significantly improves the service life of the equipment.

[0020] As the rotational speed climbs to the rated threshold, the system actively brakes the secondary ring via a hydraulic locking mechanism or an electromagnetic locking plate triggered by an electrical signal. At the instant the secondary ring transitions from a servo-driven state to a stationary locked state, a significant velocity jump occurs between it and the high-speed rotating moving ring, causing a rapid hydrodynamic pressure rise in the spiral groove. Combined with the unique spline structure and elastic deformation layer between the secondary ring and the locking sleeve, the device retains axial sliding freedom while locking in the circumferential direction, allowing the secondary ring to adaptively displace in response to the hydrodynamic pressure rise. This rapidly expands a high-pressure liquid film sealing zone with extremely high rigidity, achieving stable and reliable contactless operation. Furthermore, through a counterflow mechanism located at the far end of the sealing cavity, the system maintains liquid film stability while actively controlling the temperature and shielding impurities in the wear transfer zone through positive pressure clean liquid flow, ensuring a stable sealing environment under complex operating conditions.

[0021] In summary, this invention features a novel structure. By optimizing the sealing structure, it achieves a technological leap from passively bearing wear to actively intervening in protection. Through spatial transfer, it protects the geometric integrity of the core functional surfaces, accelerates the formation of the sealed water wall, and greatly reduces long-term maintenance costs. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0023] Figure 2 For the present invention Figure 1 Front view structural diagram;

[0024] Figure 3 For the present invention Figure 1 A schematic diagram of the side view structure;

[0025] Figure 4 This is a schematic diagram of the internal structure of the present invention;

[0026] Figure 5 This is a schematic diagram of the hydraulic sealing device.

[0027] Figure 6 This is a schematic diagram of the implementation structure of the secondary ring;

[0028] Figure 7 This is a schematic diagram of the internal structure of the secondary ring;

[0029] Figure 8 This is a schematic diagram of one implementation structure of the locking mechanism;

[0030] Figure 9 This is a schematic diagram of another implementation of the locking mechanism.

[0031] Reference numerals: 1. Pump body; 2. Outlet; 3. Inlet; 4. Impeller; 5. Shaft; 6. Shaft sleeve; 7. Set screw; 8. Moving ring seat; 9. Moving ring; 10. Secondary ring; 101. Locking sleeve; 102. Rotating block; 103. Limiting part; 104. Spline; 105. Elastic deformation layer; 106. Washer; 11. Stationary ring; 12. Stationary ring seat; 13. First sealing ring; 14. Second sealing ring; 15. Locking mechanism ; 151. Plug; 152. Piston; 153. Locking rod; 154. Return spring; 155. Locking block; 16. Reverse flow mechanism; 161. Flow regulating valve; 162. Reverse flow head; 163. Three-way valve; 17. Shut-off valve; 18. Filter; 19. Pressure reducing valve; 20. Check valve; 21. Accumulator; 22. Pressure gauge; 23. Drive rod; 24. Electromagnetic lock plate; 25. Electromagnetic assembly; 26. Reverse flow head. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0033] Example 1

[0034] This embodiment aims to provide a non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves. In existing technologies, the spiral groove surface of the rotating ring 9 and the smooth surface of the stationary ring 11 are in a sealed state due to the pre-tensioning spring. During startup, dry friction inevitably occurs, leading to severe wear on both the smooth surface and the spiral groove surface, causing hydraulic seal failure. This embodiment introduces a secondary ring 10 and a hydraulic locking mechanism 15 to transfer the friction between the rotating ring 9 and the stationary ring 11 to a non-critical area, achieving wear transfer of the friction pair, protecting the hydraulic sealing surface, and improving the service life of the equipment.

[0035] like Figure 1-4 As shown, a non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves includes a dynamic ring 9, a stationary ring 11, a secondary ring 10, and a locking mechanism 15. In this embodiment, by adding a secondary ring 10 between the stationary ring 11 and the dynamic ring 9, and applying an active control locking force to the structure of the secondary ring 10, the dry grinding behavior that would otherwise damage the hydraulic sealing structure is transferred from the precision functional surface to the preset wear-resistant surface by introducing the secondary ring 10 as a wear carrier.

[0036] like Figure 4 As shown, this embodiment is integrated into the boiler feed water pump. The pump has an impeller chamber in the middle, and a shaft end seal and a shaft connection seal on both sides. The impeller chamber has an outlet 2 and an inlet at the top and bottom, and the rotating shaft 5 passes through it. A two-stage sealing structure is provided at the shaft end seal and the shaft connection seal, namely an inner primary seal and an outer secondary seal. This embodiment mainly improves the primary seal structure.

[0037] like Figure 4-5 As shown, the power source in this embodiment is a rotating shaft 5 that runs through the pump body 1. An impeller 4 is mounted on the front end of the rotating shaft 5 via a key. The impeller 4 is located at the junction of the suction chamber and the volute cavity, and is responsible for pumping fluid from the suction chamber into the volute cavity when rotating. A bushing 6 is fitted onto the rotating shaft 5 behind the impeller 4. A moving ring seat 8 is fixed to the bushing 6 by a set screw 7, and a moving ring 9 is fixed inside the bushing 6. The moving ring 9 rotates synchronously with the rotating shaft 5, the bushing 6, and the impeller 4, and a spiral groove is machined on its end face facing the secondary ring 10.

[0038] The pump casing serves as the main support base, forming a cylindrical sealing cavity wall on its inner side. The stationary ring seat 12 is fixed to the rear end cover of the sealing cavity by flange bolts and remains coaxial with the pump casing axis. The stationary ring 11 is fitted into the inner hole of the stationary ring seat 12, and a first sealing ring 13 is provided between the stationary ring 11 and the stationary ring seat 12. The first sealing ring 13 provides radial sealing while giving the stationary ring 11 a slight axial float and self-aligning freedom, enabling it to automatically compensate for displacement errors caused by the vibration of the rotating shaft 5.

[0039] like Figure 4-7 As shown, the secondary ring 10 is rotatably mounted on the stationary ring 11, forming a hydraulic seal structure with the rotating ring 9. In implementation, the secondary ring 10 serves as an intermediate adjustment layer, positioned within the sealing cavity between the rotating ring 9 and the stationary ring 11. Specifically, the bottom of the secondary ring 10 is rotatably mounted on the stationary ring 11 via a rotary fitting structure and directly connected to the stationary ring 11. Its top end face is machined with a smooth mating surface, which mates with the spiral groove surface of the rotating ring 9. The elastic compensation mechanism (preload spring) on ​​the back of the stationary ring 11 applies an axial load, pressing the smooth end face of the secondary ring 10 tightly against the spiral groove surface of the rotating ring 9. At this point, there is no gap between the secondary ring 10 and the rotating ring 9, relying on solid contact to block the flow of the medium, achieving static zero leakage.

[0040] In the initial transient phase of pump startup, the dynamic pressure has not yet fully established. At this time, the load applied by the elastic compensation structure of the stationary ring 11 is transmitted through the secondary ring 10. Since the bottom of the secondary ring 10 is a rotary fit structure, the secondary ring 10 can rotate synchronously with the rotating ring 9 under the viscous shear force generated by the rotation of the rotating ring 9. By making the secondary ring 10 rotate synchronously with the rotating ring 9, this embodiment transfers the direct friction that originally belonged to the spiral groove surface of the rotating ring 9 and the smooth surface of the stationary ring 11 to the secondary fit surface between the bottom of the secondary ring 10 and the stationary ring 11. Since the rotating ring 9 and the secondary ring 10 are in a relatively static state, the expensive and precision spiral groove core structure is protected from dry friction damage, ensuring that the forming surface of the hydraulic seal structure always maintains geometric integrity.

[0041] In this embodiment, a secondary ring 10 is provided between the moving ring 9 and the stationary ring 11. By decomposing a complex friction process into two independent mating surfaces, the purpose of protecting the core structure is achieved. The protected object is the core functional surface. The top end face of the secondary ring 10 is a high-precision ground smooth surface, corresponding to the spiral groove surface of the moving ring 9. In operation, a high-pressure liquid film blocking zone needs to be formed here to support the end face. The wear transfer zone is a pre-designed wear-resistant surface. The bottom of the secondary ring 10 is mounted on the stationary ring 11 through a rotary mating structure. This mating surface is designed as a special wear-resistant friction pair, using materials with low friction coefficient and high thermal conductivity (such as impregnated graphite or modified PTFE), possessing a friction pair with low heat generation and high heat dissipation.

[0042] As the rotating shaft 5 drives the moving ring 9 and the auxiliary ring 10 to accelerate to near their rated speed, the high-pressure water flow introduced by the water inlet branch drives the piston 152 to move, and the locking block 155 quickly locks the auxiliary ring 10. The auxiliary ring 10, which was originally moving, stops rotating, while the moving ring 9 continues to rotate at high speed at its rated speed. Because the auxiliary ring 10 is locked, a huge relative speed difference is instantly generated between the moving ring 9 and the auxiliary ring 10. According to the principles of fluid dynamics, the spiral groove rapidly generates a fluid dynamic pressure rise under this instantaneous speed difference, creating a high-pressure liquid film blockage zone with extremely high rigidity between the end faces of the moving and auxiliary rings 10 in a very short time. The friction time between the locked auxiliary ring 10 and the moving ring 9 is short, which can quickly form a blockage zone and block the leakage of the medium from the volute cavity to the rear end of the sealing cavity.

[0043] The locking mechanism 15 is used to lock the secondary ring 10 relative to the stationary ring 11, aiming to achieve active braking and positioning of the secondary ring 10 using the fluid pressure of the pump system. The plug cylinder 151 is fixed to the pump casing wall by threads, and a piston 152 is precisely fitted inside the plug cylinder 151. The upper chamber of the piston 152 is connected to the water inlet 3 of the outlet 2 of the pump body 1 through a water inlet pipe. In the specific implementation structure, the locking mechanism 15 includes a locking block 155, a return spring 154, a locking rod 153, and a piston 152. The piston 152 is disposed inside the plug cylinder 151 and receives the water pressure introduced from the outlet 2. The locking rod 153 is fixed to the bottom of the piston 152. The return spring 154 is located between the plug cylinder 151 and the piston 152 and is sleeved on the locking rod 153. The locking block 155 is fixed to the bottom of the locking rod 153 and corresponds to the secondary ring 10.

[0044] In this embodiment, hydraulic power is used as the driving unit. The plug cylinder 151 is fixed to the pump casing wall by threads. A piston 152 is fitted inside the plug cylinder 151. The upper chamber of the piston 152 is connected to the water inlet 3 near the outlet 2 through a water inlet pipe. The top end of the locking rod 153 is fixed to the bottom of the piston 152, and the bottom end extends into the cavity through the sealed cavity wall and is connected to an arc-shaped locking block 155. The return spring 154 is located between the bottom of the plug cylinder 151 and the piston 152, and is fitted around the outer periphery of the locking rod 153 to form a return unit.

[0045] like Figure 8As shown, in the specific implementation structure, a water inlet 3 is provided near the outlet 2 of the pump body 1. The water inlet 3 is connected to the inlet of the plug cylinder 151 in sequence via a shut-off valve 17, a filter 18, a pressure reducing valve 19, a check valve 20, an accumulator 21, and a pressure gauge 22. To ensure that the piston 152 obtains a stable and sufficient force, the following components are arranged in sequence along the fluid direction on the water inlet branch: a shut-off valve 17, a filter 18, a pressure reducing valve 19, a check valve 20, an accumulator 21, and a pressure gauge 22. The filter 18 is used to filter out impurities in the medium, prevent the piston 152 from jamming, and ensure the reliability of pressure transmission. The pressure reducing valve 19 works in conjunction with the accumulator 21 to regulate and stabilize the pressure at the pump outlet 2 at a preset value, eliminate pressure pulsation, and ensure that the locking mechanism 15 obtains a continuous and constant axial driving force.

[0046] The working logic of the locking mechanism 15 is as follows: When the pump starts, the pressure at outlet 2 rises, and the high-pressure fluid in the inlet 3 enters the plug cylinder 151 through the inlet branch. The high-pressure fluid acts on the effective pressure-bearing area at the top of the piston 152, generating an axial force sufficient to overcome the preload of the return spring 154 and the frictional resistance. This force is rigidly transmitted to the locking block 155 via the locking rod 153. Under water pressure, the locking block 155 radially presses the secondary ring 10, using the frictional torque generated by the contact surface to overcome the rotational driving effect of the moving ring 9 on the secondary ring 10, forcing the secondary ring 10 to instantly switch from the following rotational state to the stationary locked state. This process generates a velocity step between the moving ring 9 and the secondary ring 10, inducing a hydrodynamic pressure rise effect in the spiral groove. When the pump stops, the impeller 4 speed decreases, the water pressure at the pump outlet 2 decreases, the fluid pressure at the top of the piston 152 disappears, and the return spring 154 uses its stored elastic potential energy to drive the piston 152 and the locking rod 153 to return upward. The locking block 155 then disengages from the secondary ring 10, allowing the secondary ring 10 to regain its free floating degree of freedom. This quickly reduces the speed difference between the secondary ring 10 and the moving ring 9, causing the high-pressure liquid film sealing zone to fail rapidly. Under the action of the pre-tightening spring on the back of the stationary ring 11, the secondary ring 10 and the moving ring 9 quickly come into contact, forming a seal again.

[0047] Traditional seals concentrate all the pressure of static sealing and dynamic film formation on the mating surfaces of the moving and stationary rings 11. This embodiment introduces a secondary ring 10 as an intermediate carrier, physically decomposing the complex process into two independent mating surfaces: one functional surface responsible for forming the high-pressure liquid film sealing zone at rated speed, and the other friction surface responsible for bearing the mechanical friction caused by insufficient dynamic pressure during start-stop transients. Simultaneously, the hydraulic locking mechanism 15 implements a logic control of the secondary ring 10, first moving and then locking, achieving rigid protection of the precision spiral groove surface. This embodiment realizes the spatial transfer of dry grinding from important functional surfaces to non-critical wear-resistant surfaces. Combined with the application of high thermal conductivity and low friction materials, it effectively suppresses frictional heat damage to the structure, ensuring the long-term reliability of the sealing device under frequent start-stop conditions.

[0048] Example 2

[0049] This embodiment, based on Embodiment 1, further optimizes the positioning and motion degrees of freedom of the sub-ring 10. For example... Figure 7 As shown, the secondary ring 10 is coaxially connected to the locking sleeve 101 via a spline 104 structure on its outer circumference. This spline 104 connection ensures that the locking sleeve 101 and the secondary ring 10 are constrained in the circumferential direction (i.e., they rotate or stop synchronously), but allow for sliding freedom in the axial direction.

[0050] In the implemented structure, the secondary ring 10 is connected to a locking sleeve 101 via a spline 104 structure. An elastic deformation layer 105 is provided at the end of the locking sleeve 101, and the outer side of the locking sleeve 101 corresponds to the locking mechanism 15. In this embodiment, an independent friction surface is provided on the outer surface of the end of the locking sleeve 101. This friction surface faces the locking block 155 of the locking mechanism 15 and is used to directly bear the radial compressive force of the locking block 155 during the locking stage, thereby generating a frictional torque sufficient to brake the rotation of the locking sleeve 101.

[0051] Meanwhile, an independent elastic deformation layer 105 is provided at the connection between the locking sleeve 101 and the end face of the secondary ring 10. During actual operation, when the locking mechanism 15 drives the locking block 155 to press against the friction surface at the end of the locking sleeve 101, the locking sleeve 101 instantly switches from a rotating state to a stationary state. At this time, the elastic deformation layer 105 provided between the locking sleeve 101 and the secondary ring 10 provides a small displacement buffer clearance for the main body of the secondary ring 10 through its axial flexible deformation. Combined with the axial sliding characteristics of the spline 104 structure, even after the locking sleeve 101 is fully braked and locked, the main body of the secondary ring 10 can still respond to the hydrodynamic lift generated by the spiral groove and undergo adaptive micro-displacement in the axial direction.

[0052] The moving ring 9 is mounted on the bushing 6, and the stationary ring 11 is mounted on the stationary ring seat 12 via an elastic compensation mechanism. A rotating groove is provided at the outer end of the stationary ring 11, and a rotating seat is provided at the inner end of the secondary ring 10, which is fitted into the rotating groove. The rotating seat includes multiple rotating blocks 102, which are assembled below the locking sleeve 101 and fixed to the secondary ring 10. A washer 106 is provided between the rotating seat and the locking sleeve 101 for axial load transmission. A second sealing ring 14 is provided between the rotating groove and the rotating seat to maintain an auxiliary seal and prevent the medium from leaking into the gap between the stationary ring 11 and the bushing 6 through the gap. The second sealing ring 14 is a low-friction sealing ring (such as polytetrafluoroethylene).

[0053] A rotating seat is provided at the inner end of the secondary ring 10. This rotating seat is composed of multiple arc-shaped rotating blocks 102 and is fixed on the secondary ring 10. A limiting part 103 is provided at the bottom of the rotating seat and is adapted to fit into the rotating groove at the outer end of the stationary ring 11. The rotating block 102, as a pre-designed rotating component, is made of a wear-resistant material with high thermal conductivity and self-lubrication. It is used to transfer dry wear from the spiral groove of the moving ring 9 during the start-up follow-up phase. At the same time, the combined structure makes the rotating block 102 an independently replaceable part, which is convenient for maintenance.

[0054] Example 3

[0055] This embodiment, based on the above embodiment, further includes a reversing mechanism 16 for enhancing environmental control and temperature control performance. For example... Figure 8 As shown, the backflow mechanism 16 includes a backflow head 162, a three-way valve 163 and a flow regulating valve 161. The three-way valve 163 is connected between the filter 18 and the pressure reducing valve 19, and its branch is connected to the flow regulating valve 161 and the backflow head 162. The backflow head 162 is correspondingly arranged inside the pump body 1.

[0056] like Figure 4 As shown, a locking mechanism 16, a backflow mechanism 16, and a return head 26 are provided at the pump body sealing structure. The locking mechanism 16 and the backflow mechanism 16 are for water inlet, and the return head is for water outlet. Based on the structure of Embodiment 1, a three-way valve 163 is connected in series between the filter 18 and the pressure reducing valve 19 in the water inlet branch. Its inlet end receives the filtered and purified fluid, and its outlet end supplies pressure to the pressure reducing valve 19. The branch is connected in sequence to the flow regulating valve 161 and the backflow head 162. The backflow head 162 is arranged in the sealing cavity of the pump body 1. In terms of spatial layout, the backflow head 162 is arranged at the end of the sealing cavity away from the moving ring 9 (i.e., near the back area of ​​the stationary ring seat 12). By introducing clean liquid, a positive pressure protection field is established in the sealing cavity, which slowly flows from the rear end to the front end of the volute cavity. The reflux fluid flows through this area, preferentially performing submerged convection heat transfer on the rotating block 102 at the bottom of the secondary ring 10, which is responsible for wear transfer. This rapidly removes the frictional heat generated during the start-up phase, ensuring the dimensional stability of the secondary ring 10 and its internal elastic deformation layer 105. Simultaneously, the return water flows outward through the recovery return head 26, forming a circulation.

[0057] Example 4

[0058] This embodiment provides an active locking system based on electromagnetic induction, which aims to achieve precise intervention in the locking timing of the sub-ring 10 through the logical control of electrical signals.

[0059] like Figure 9 As shown, the locking mechanism 15 uses an electric lock plate to lock the secondary ring 10. In specific implementation, as follows: Figure 8As shown, the locking mechanism 15 is electrically driven and locks the secondary ring 10 using electromagnetic force. Structurally, it includes an electromagnetic component 25 mounted on the pump casing or sealing cavity wall and an electromagnetic locking plate 24 driven by it. In conjunction with the piston 152 structure in Embodiment 1, a drive rod 23 is provided at the end of the piston 152 structure, and the electromagnetic locking plate 24 is arranged at the end of the drive rod 23. The electromagnetic component 25 is located below the electromagnetic locking plate 24. During the initial pump startup, the electromagnetic component 25 is de-energized, and the electromagnetic locking plate 24 remains separated from the locking sleeve 101 under the action of the return spring 154.

[0060] When the sensor detects that the rotational speed of the shaft 5 has reached the set rated threshold, the controller sends a command to energize the electromagnetic component 25. The electromagnetic locking plate 24 moves downward, overcoming the elastic force of the return spring 154, and drives the electromagnetic locking plate 24 to press against the friction layer of the locking sleeve 101. In response to the electromagnetic signal, the secondary ring 10 is locked, generating a huge relative speed difference with the high-speed rotating moving ring 9, which rapidly establishes the high-pressure liquid film sealing zone.

[0061] When a shutdown signal is received or a decrease in speed is detected, the electromagnetic component 25 is de-energized and released, and the electromagnetic lock plate 24 is reset under the action of the return spring 154. The secondary ring 10 is released from the lock and resumes rotation, the high-pressure liquid film thrust is rapidly reduced, and under the action of the elastic compensation mechanism, it re-fits with the moving ring 9 to maintain a static seal.

[0062] This embodiment controls the locking action with electrical signals, eliminating dependence on the fluid pressure inside the pump and significantly improving the response accuracy and reliability of the sealing system under low-pressure start-up or complex operating conditions. By using preset speed triggering logic, the locking action is ensured to occur only when the liquid film meets the conditions for film formation, minimizing contact loss of the sealing surface under unstable conditions and improving the overall stability of the equipment.

Claims

1. A non-contact hydraulic sealing device based on the hydrodynamic effect of a spiral groove, characterized in that: It includes a rotating ring, a stationary ring, a secondary ring, and a locking mechanism; the secondary ring is rotatably mounted on the stationary ring and forms a hydraulic seal structure corresponding to the rotating ring; the locking mechanism is used to lock the secondary ring relative to the stationary ring.

2. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: The locking mechanism includes a locking block, a return spring, a locking rod, and a piston. The piston is disposed inside the plug cylinder and receives driving force. The locking rod is fixed to the bottom of the piston. The return spring is located between the plug cylinder and the piston and is fitted onto the locking rod. The locking block is fixed to the bottom of the locking rod and corresponds to the secondary ring.

3. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: The driving force is the water pressure introduced from the outlet of the pump body. The outlet of the pump body is provided with a water inlet, which is connected to the inlet of the plug cylinder in sequence via a shut-off valve, a filter, a pressure reducing valve, a check valve, an accumulator and a pressure gauge.

4. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: It also includes a backflow mechanism, which includes a backflow head, a three-way valve and a flow regulating valve. The three-way valve is connected between the filter and the pressure reducing valve, and its branch is connected to the flow regulating valve and the backflow head. The backflow head is correspondingly installed in the pump body.

5. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 2, characterized in that: The driving force is the locking force provided by the electric lock plate. The locking mechanism also includes an electromagnetic component, a drive rod, and an electromagnetic lock plate. The electromagnetic component is installed on the pump housing. One end of the drive rod is connected to the piston, and the other end is provided with an electromagnetic lock plate corresponding to the electromagnetic component.

6. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: The moving ring is fixed on the moving ring seat at the end of the bushing, and a spiral groove is provided at the end of the moving ring.

7. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: The stationary ring is fitted onto the stationary ring seat, and a first sealing ring is provided between the stationary ring and the stationary ring seat.

8. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: The secondary ring is connected to a locking sleeve via a spline structure. The end of the locking sleeve is provided with an elastic deformation layer, and the outer side of the locking sleeve corresponds to the locking mechanism.

9. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 1, characterized in that: The moving ring is mounted on the bushing, and the stationary ring is mounted on the stationary ring seat via an elastic compensation mechanism. A rotating groove is provided at the outer end of the stationary ring, and a rotating seat is provided at the inner end of the secondary ring, with the rotating seat fitted inside the rotating groove.

10. The non-contact hydraulic sealing device based on the hydrodynamic effect of spiral grooves according to claim 9, characterized in that: The rotating seat includes multiple rotating blocks, which are arranged below the locking sleeve and fixed on the secondary ring. A washer is provided between the rotating seat and the locking sleeve, and a second sealing ring is provided between the rotating groove and the rotating seat.

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