High performance double mechanical seal rotary union

Abstract

The application relates to the technical field of mechanical sealing devices, in particular to a high-performance double-end-face sealing rotary joint which comprises an outer shell, a rotating main shaft, a sealing assembly and a pressure compensation mechanism. A main flow channel is arranged in the rotating main shaft, the sealing assembly comprises a dynamic ring and a static ring, the dynamic ring rotates with the main shaft, and the static ring is connected with the pressure compensation mechanism. The pressure compensation mechanism comprises a compensation piston and a pressure guide channel which is communicated with the main flow channel, fluid medium enters the pressure guide channel to push the compensation piston, and an axial adhering thrust is applied to the static ring. The application can realize axial real-time compensation after the sealing surface is worn.

Description

Technical Field

[0001] This utility model pertains to mechanical sealing devices, specifically a high-performance double-end face sealing rotary joint. Background Technology

[0002] A rotary joint is a key connecting element used to realize the transfer of fluid media between rotating and stationary parts. It is widely used in chemical, pharmaceutical, papermaking, rubber, plastic and other industrial fields, and plays an important role in conveying media such as cooling water, steam and heat transfer oil in the continuous production process of equipment.

[0003] Rotary joints with double-end sealing structures are often used in operating conditions with high sealing performance requirements because they have high sealing reliability and safety, can effectively prevent media leakage and adapt to certain pressure fluctuation environments. By setting auxiliary sealing systems on both sides of the main seal and cooperating with a circulating sealing liquid device, the operational stability and service life can be further improved.

[0004] However, most existing double-end face sealing rotary joints use a fixed pre-tightening structure to apply contact pressure to the sealing ring, relying on springs or bellows to provide continuous clamping force to maintain the contact seal between the moving ring and the stationary ring. However, during long-term operation, the axial displacement caused by wear is difficult to compensate in real time, affecting the contact state of the sealing interface, and thus limiting the stability of the sealing performance. This problem is particularly obvious under conditions of frequent start-stop or large load changes. Utility Model Content

[0005] This invention provides a high-performance double-end face sealing rotary joint, which aims to solve the problem in the prior art that the axial displacement caused by the wear of the sealing ring is difficult to compensate in real time, thus affecting the sealing interface fit and performance stability.

[0006] To achieve the above objectives, this utility model provides the following technical solution: The high-performance double-end-face sealed rotary joint includes a housing, a rotating spindle, a sealing assembly, and a pressure compensation mechanism, wherein: The rotating spindle is rotatably disposed inside the outer casing, and the interior of the rotating spindle has a main channel for conveying fluid medium.

[0007] The sealing assembly includes a stationary ring and a rotating ring. The rotating ring is fixedly sleeved on the outer peripheral wall of the rotating spindle and rotates synchronously with the rotating spindle. The stationary ring is connected to the pressure compensation mechanism, and the end face of the stationary ring is in contact with the end face of the rotating ring to form a dynamic sealing interface.

[0008] The pressure compensation mechanism is disposed in the inner cavity of the outer shell. The pressure compensation mechanism includes a compensation piston, which can slide within the outer shell along the axial direction of the rotating main shaft. The stationary ring is fixed to the end of the compensation piston facing the rotating ring. The pressure compensation mechanism also includes a pressure guiding channel connected to the main channel. The pressure guiding channel introduces fluid medium into the side of the compensation piston away from the rotating ring. The pressure of the fluid medium pushes the compensation piston, thereby applying a continuous axial contact thrust to the stationary ring.

[0009] Preferably, the pressure compensation mechanism further includes a piston sleeve fixed to the inner wall of the outer casing, the compensation piston being slidably received in the inner cavity of the piston sleeve, a pressure chamber being defined between the compensation piston and the inner wall of the piston sleeve, and the outlet of the pressure guiding channel communicating with the pressure chamber.

[0010] Preferably, an annular sealing groove is formed on the outer peripheral wall of the compensating piston, and a piston sealing ring is installed in the annular sealing groove. The piston sealing ring abuts against the inner wall of the piston sleeve to dynamically seal the pressure chamber.

[0011] Preferably, the pressure compensation mechanism further includes an elastic preload member disposed in the pressure chamber, the two ends of the elastic preload member abutting against the inner bottom wall of the piston sleeve and the end face of the compensation piston away from the moving ring, respectively, for providing an initial contact force to the stationary ring when the system is not under pressure.

[0012] Preferably, the outer casing is provided with a guide structure that cooperates with the compensation piston. The guide structure includes an axial guide groove formed on the inner wall of the piston sleeve and a guide pin fixed to the outer peripheral wall of the compensation piston. The end of the guide pin is slidably fitted into the axial guide groove to limit the circumferential rotation of the compensation piston.

[0013] Preferably, the pressure guiding channel includes a radial drainage hole formed on the wall of the rotating spindle tube, an annular flow collecting groove formed on the inner circumferential wall of the piston sleeve, and a connecting hole connecting the annular flow collecting groove and the pressure chamber, wherein the outlet of the radial drainage hole is always opposite to the annular flow collecting groove.

[0014] Preferably, the end of the outer casing is provided with an end cap, and the end cap has a through indicator hole. The pressure compensation mechanism also includes a wear indicator rod, one end of which is fixedly connected to the rear end of the compensation piston, and the other end passes through the indicator hole and extends to the outside of the outer casing.

[0015] Preferably, the stationary ring is connected to the front end face of the compensating piston by an anti-rotation pin, the rotating ring is connected to the rotating spindle by a key, and the outer shell is fixedly connected to the piston sleeve by threads.

[0016] The high-performance double-end face sealing rotary joint provided by this utility model has the following beneficial effects: This high-performance double-end-face sealing rotary joint, through a pressure compensation mechanism, introduces pressurized working medium from the main channel into the pressure chamber behind the compensation piston via a pressure guide channel. The medium's own pressure acts on the compensation piston, generating an axial thrust positively correlated with the system pressure. This thrust continuously acts on the stationary ring, pushing it towards the moving ring. When the sealing surfaces of the stationary and moving rings wear, the resulting minute axial gap is immediately filled by the hydraulically driven compensation piston, achieving dynamic and real-time compensation for wear on the sealing surfaces and maintaining a constant contact pressure between the sealing interfaces. This structure changes the traditional method of relying on springs or other fixed preload elements. Its compensation force adaptively adjusts with the operating pressure, thus maintaining a tight seal even under long-term operation, frequent start-stop, or load changes, significantly improving the sealing reliability and service life of the rotary joint. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the high-performance double-end face sealing rotary joint of this utility model. Figure 2 This is a cross-sectional view showing the connection relationship between the sealing assembly and the pressure compensation mechanism according to an embodiment of this application; Figure 3 This is a partially enlarged schematic diagram of the pressure compensation mechanism of this utility model; Figure 4 This is a schematic diagram of the compensating piston and piston sleeve mating structure according to an embodiment of this application; Explanation of reference numerals in the attached figures: 1. Outer shell; 2. Rotating spindle; 3. Main flow channel; 4. Stationary ring; 5. Rotating ring; 6. Dynamic sealing interface; 7. Compensating piston; 8. Pressure chamber; 9. Piston sleeve; 10. Pressure guiding channel; 11. Radial drainage hole; 12. Annular collecting groove; 13. Connecting hole; 14. Piston seal ring; 15. Elastic preload element; 16. Guide pin; 17. Axial guide groove; 18. Wear indicator rod. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figures 1 to 4 This utility model provides a high-performance double-end face sealed rotary joint, which is used in industrial fluid transportation systems to connect fixed pipes and rotating equipment, and to transmit high-pressure or high-temperature fluid media during rotation.

[0020] Please see Figure 1 This utility model provides a technical solution: a high-performance double-end face sealed rotary joint, which includes a housing 1, a rotating spindle 2 rotatably disposed inside the housing 1, a sealing assembly installed between the rotating spindle 2 and the housing 1, and a pressure compensation mechanism for axial force compensation of the sealing assembly. A main channel 3 is provided on the central axis of the rotating spindle 2, passing through both ends of the rotating spindle 2, through which fluid medium flows between the inside and outside of the rotary joint. The housing 1 is a hollow cylindrical structure, providing a mounting base and protection for the internal components. The rotating spindle 2 is rotatably supported inside the housing 1 by bearing components (not shown). One end of the rotating spindle 2 extends out of the housing 1 and connects to a rotating device, while the other end connects to a fixed pipe.

[0021] Please see Figure 2 The sealing assembly, the core component for achieving fluid sealing between the stationary and moving parts, comprises a stationary ring 4 and a moving ring 5. The moving ring 5 is fixedly fitted onto the outer peripheral wall of the rotating main shaft 2 via a key connection and rotates synchronously with the rotating main shaft 2. The stationary ring 4 is connected to the front end of the pressure compensation mechanism and is movable along the axial direction of the rotating main shaft 2, but is restricted in the circumferential direction and does not rotate. One end face of the stationary ring 4 and one end face of the moving ring 5 are in contact with each other, and these two precision-machined end faces together form a dynamic sealing interface 6. During equipment operation, the moving ring 5 rotates at high speed while the stationary ring 4 remains stationary. During the relative rotation of the two rings, the dynamic sealing interface 6 blocks the leakage path of the fluid medium from the main channel 3 to the interior of the outer casing 1.

[0022] Please see Figure 2 and Figure 3The pressure compensation mechanism is the key structure of this invention for real-time compensation of wear on the dynamic sealing interface 6. This mechanism is located within the inner cavity of the outer casing 1 and is directly connected to the stationary ring 4. The pressure compensation mechanism includes a piston sleeve 9, which is a stepped cylindrical structure and is threadedly fixed to the inner wall of the outer casing 1, forming an integral part of the outer casing 1. The pressure compensation mechanism also includes a compensation piston 7, which is slidably housed within the inner cavity of the piston sleeve 9 and can reciprocate within the piston sleeve 9 along the axis of the rotating main shaft 2. The stationary ring 4 is fixedly mounted on the end face of the compensation piston 7 facing the dynamic ring 5 by an anti-rotation pin. A sealed pressure chamber 8 is defined between the rear end face of the compensation piston 7 and the inner bottom wall of the piston sleeve 9.

[0023] For effective dynamic sealing of pressure chamber 8, please refer to [link / reference]. Figure 3 One or more annular sealing grooves are formed on the outer peripheral wall of the compensating piston 7, and a piston sealing ring 14 is installed in each annular sealing groove. When the compensating piston 7 is installed in the piston sleeve 9, the outer peripheral surface of the piston sealing ring 14 abuts tightly against the inner wall of the piston sleeve 9. As the compensating piston 7 slides axially, the piston sealing ring 14 always maintains a sealing state on the pressure chamber 8, preventing the pressurized fluid in the pressure chamber 8 from leaking to other areas of the outer casing 1.

[0024] Please continue reading. Figure 3 To maintain necessary contact pressure between the two sealing surfaces of the dynamic sealing interface 6 during the initial startup of the rotary joint or when the system is not under pressure, the pressure compensation mechanism also includes an elastic preload element 15 inside the pressure chamber 8. In this embodiment, the elastic preload element 15 is specifically a coiled compression spring. The elastic preload element 15 is axially positioned within the pressure chamber 8, with one end abutting against the inner bottom wall of the piston sleeve 9 and the other end abutting against the rear end face of the compensation piston 7 away from the moving ring 5. After installation, the elastic preload element 15 is in a compressed state, and its elastic force continuously pushes the compensation piston 7 toward the moving ring 5, thereby applying an initial axial contact force to the stationary ring 4.

[0025] Please see Figure 4To limit the compensating piston 7 to purely axial sliding within the piston sleeve 9 and prevent circumferential rotation with the main rotating shaft 2, a guide structure cooperating with the compensating piston 7 is provided on the outer casing 1. This guide structure specifically includes one or more axial guide grooves 17 formed on the inner wall of the piston sleeve 9, and one or more guide pins 16 fixed to the outer peripheral wall of the compensating piston 7. The ends of the guide pins 16 slidably engage within the corresponding axial guide grooves 17. When the compensating piston 7 is subjected to axial force, the guide pins 16 slide along the length of the axial guide grooves 17; when the compensating piston 7 is subjected to any possible torque component, the sidewalls of the guide pins 16 abut against the sidewalls of the axial guide grooves 17, thereby preventing circumferential rotation of the compensating piston 7.

[0026] Please see Figure 2 and Figure 3 The core of this invention lies in using the pressure of the fluid medium itself to compensate for seal wear. This is achieved through a pressure guiding channel 10. The pressure guiding channel 10 connects the main flow channel 3 and the pressure chamber 8. Specifically, the pressure guiding channel 10 consists of several parts. First, on the pipe wall of the rotating spindle 2, corresponding to the position of the pressure compensation mechanism, one or more radial drainage holes 11 are radially opened. The inner opening of the radial drainage hole 11 communicates with the main flow channel 3, while the outer opening is on the outer peripheral wall of the rotating spindle 2. Second, on the inner peripheral wall of the piston sleeve 9, opposite to the radial drainage hole 11, an annular collecting groove 12 is formed. The width of the annular collecting groove 12 covers the outlet of the radial drainage hole 11, ensuring that the outlet of the radial drainage hole 11 remains connected to the annular collecting groove 12 regardless of the rotation angle of the rotating spindle 2. Finally, one or more connecting holes 13 are provided on the wall of the piston sleeve 9, extending from the bottom of the annular collecting groove 12. The connecting holes 13 penetrate the wall thickness of the piston sleeve 9, and their outlets lead directly to the pressure chamber 8. In this way, the high-pressure fluid medium in the main flow channel 3 can be introduced into the pressure chamber 8 behind the compensating piston 7 through the path formed by the radial drainage hole 11, the annular collecting groove 12, and the connecting hole 13.

[0027] Please see Figure 4 To visually monitor the wear condition of the sealing assembly, this invention also includes a wear indicator mechanism. The end of the outer casing 1 furthest from the rotating ring 5 is sealed by an end cap with a through indicator hole. The pressure compensation mechanism also includes a slender wear indicator rod 18. One end of the wear indicator rod 18 is fixedly connected to the center of the rear end face of the compensation piston 7, its body extends along the axis of the rotating main shaft 2, and the other end passes through the indicator hole on the end cap and extends to the outside of the outer casing 1. The wear indicator rod 18 moves axially synchronously with the compensation piston 7.

[0028] In this invention, the working process of the high-performance double-end-face sealing rotary joint is as follows: In the initial installation state, the elastic preload 15 is in a compressed state, and its elastic force is transmitted to the stationary ring 4 through the compensation piston 7, so that the end face of the stationary ring 4 is tightly fitted with the end face of the moving ring 5, forming an initial contact pressure at the dynamic sealing interface 6.

[0029] When the rotary joint starts working, after the high-pressure fluid medium enters the main flow channel 3, a portion of the fluid medium will enter the pressure chamber 8 through the pressure guide channel 10. The specific flow path is: main flow channel 3, radial drainage hole 11, annular collection groove 12, connecting hole 13, and finally reaching the pressure chamber 8. The fluid medium entering the pressure chamber 8 will apply a uniform hydraulic or pneumatic pressure to the entire rear end face of the compensating piston 7. This pressure acts on the effective area of ​​the compensating piston 7, generating a strong axial thrust. This axial thrust, combined with the elastic force of the elastic preload 15, acts together on the stationary ring 4, pushing it more tightly towards the moving ring 5, thereby establishing a sealing specific pressure at the dynamic sealing interface 6 that is positively correlated with the system medium pressure and sufficient to resist the tendency of medium leakage.

[0030] During long-term operation, the end faces of the stationary ring 4 and the dynamic ring 5 at the dynamic sealing interface 6 will wear due to relatively high-speed friction, resulting in a tiny axial gap. Once this gap appears, the sealing pressure at the dynamic sealing interface 6 will drop instantaneously. However, since the pressure in the pressure chamber 8 is always present, the axial thrust acting on the compensation piston 7 will immediately push the compensation piston 7 and the stationary ring 4 forward until the tiny gap is completely filled, and the contact state and sealing specific pressure of the dynamic sealing interface 6 will return to the set value. This compensation process occurs instantaneously and automatically.

[0031] As wear accumulates, the axial position of the compensating piston 7 gradually moves forward. Since the wear indicator rod 18 is fixedly connected to the compensating piston 7, each forward movement of the compensating piston 7 will cause the wear indicator rod 18 to move forward synchronously. The operator can judge the cumulative wear of the dynamic sealing interface 6 by observing or measuring the change in the length of the wear indicator rod 18 extending outside the outer casing 1. When the extension length reaches the preset limit value, it indicates that the sealing ring is about to end its service life, and replacement can be arranged in advance for preventive maintenance.

[0032] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-performance double-end-face sealed rotary joint, characterized in that: It includes an outer casing (1), a rotating spindle (2), a sealing assembly, and a pressure compensation mechanism, wherein: The rotating spindle (2) is rotatably disposed inside the outer shell (1), and the rotating spindle (2) has a main channel (3) inside. The sealing assembly includes a stationary ring (4) and a rotating ring (5). The rotating ring (5) is fixed to the outer peripheral wall of the rotating spindle (2) and rotates with the rotating spindle (2). The stationary ring (4) is connected to the pressure compensation mechanism. The end face of the stationary ring (4) and the end face of the rotating ring (5) are in contact to form a dynamic sealing interface (6). The pressure compensation mechanism is located in the inner cavity of the outer shell (1). The pressure compensation mechanism includes a compensation piston (7) and a pressure guiding channel (10). The compensation piston (7) can slide along the axial direction of the rotating main shaft (2). The stationary ring (4) is fixed to the end of the compensation piston (7) facing the moving ring (5). The pressure guiding channel (10) is connected to the main channel (3). The pressure guiding channel (10) introduces the fluid medium into the side of the compensation piston (7) away from the moving ring (5). The pressure of the fluid medium pushes the compensation piston (7). The compensation piston (7) applies an axial thrust to the stationary ring (4).

2. The high-performance double-end face sealing rotary joint according to claim 1, characterized in that: The pressure compensation mechanism further includes a piston sleeve (9) fixed to the inner wall of the outer shell (1), the compensation piston (7) is slidably received in the inner cavity of the piston sleeve (9), the compensation piston (7) and the inner wall of the piston sleeve (9) define a pressure chamber (8), and the outlet of the pressure guiding channel (10) communicates with the pressure chamber (8).

3. The high-performance double-end face sealing rotary joint according to claim 2, characterized in that: The outer peripheral wall of the compensation piston (7) is provided with an annular sealing groove, and a piston sealing ring (14) is installed in the annular sealing groove. The piston sealing ring (14) abuts against the inner wall of the piston sleeve (9).

4. The high-performance double-end face sealing rotary joint according to claim 2, characterized in that: The pressure compensation mechanism also includes an elastic preload member (15) disposed in the pressure chamber (8), the two ends of which abut against the inner bottom wall of the piston sleeve (9) and the end face of the compensation piston (7) away from the moving ring (5), respectively.

5. The high-performance double-end face sealing rotary joint according to claim 2, characterized in that: The inner wall of the piston sleeve (9) is provided with an axial guide groove (17), and the outer peripheral wall of the compensation piston (7) is fixed with a guide pin (16), the end of the guide pin (16) being slidably fitted into the axial guide groove (17).

6. The high-performance double-end face sealing rotary joint according to claim 2, characterized in that: The pressure guiding channel (10) includes a radial drainage hole (11) opened on the wall of the rotating spindle (2), an annular flow collecting groove (12) opened on the inner peripheral wall of the piston sleeve (9), and a connecting hole (13) connecting the annular flow collecting groove (12) and the pressure chamber (8). The outlet of the radial drainage hole (11) is opposite to the annular flow collecting groove (12).

7. The high-performance double-end face sealing rotary joint according to claim 1, characterized in that: The end of the outer casing (1) is provided with an end cap, and an indicator hole is provided on the end cap. The pressure compensation mechanism also includes a wear indicator rod (18). One end of the wear indicator rod (18) is fixedly connected to the rear end of the compensation piston (7), and the other end passes through the indicator hole and extends to the outside of the outer casing (1).

8. The high-performance double-end face sealing rotary joint according to claim 2, characterized in that: The stationary ring (4) is connected to the front end face of the compensating piston (7) by an anti-rotation pin, the rotating ring (5) is connected to the rotating spindle (2) by a key, and the outer shell (1) is fixedly connected to the piston sleeve (9) by a thread.

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