A micro-leakage reverse reflux high-pressure mechanical sealing device

Abstract

The present invention provides a micro-leakage reverse reflux type high-pressure mechanical sealing device, comprising a sleeve ring seat, a sealing gland, a pre-installed ring, a rotating fixed ring, a high-pressure sealing assembly, a rotating sealing ring, a stationary sealing ring, a stationary ring seat, and a supporting spring. A main shaft runs through the interior of the sleeve ring seat, the rotating fixed ring is fixedly installed on one end of the sleeve ring seat, the sealing gland is fixedly connected to a pump connector, the pre-installed ring is fixedly connected to the sealing gland, and the high-pressure sealing assembly is arranged between the rotating sealing ring and the sleeve ring seat, and between the stationary sealing ring and the stationary ring seat. The sealing device increases lubrication by introducing a small amount of high-pressure liquid into the sealing end face, and at the same time, the micro-leakage generated by the sealing end face reversely refluxes to the high-pressure area, which can reduce the wear of the sealing end face and control the sealing leakage. While ensuring the service life of the sealing device, the sealing performance under high pressure is also greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical seals for high-pressure pumps, in particular to a micro-leakage reverse reflux type high-pressure mechanical seal device. Background Art

[0002] In recent years, the high-end equipment manufacturing industry has developed rapidly, and the speed of equipment technology update has accelerated, moving towards higher parameters and extreme working conditions. Mechanical seals, as key basic components, are used in pumps and similar rotating mechanical equipment. Their function is to prevent medium leakage, which directly affects the equipment's operating efficiency and safety to a large extent; therefore, with the trend of extreme equipment operating parameters, the working parameters of mechanical seal products will inevitably increase accordingly. At present, the maximum working pressure of high-pressure pumps for conveying liquids has exceeded 15MPa, which puts forward strict requirements on the design of its supporting mechanical seal products, which not only ensures that the friction torque of the seal operating end face is small, but also controls the leakage of the seal end face; however, the current high-pressure mechanical seal products are designed to increase end face lubrication and control end face wear in order to increase life. Reducing liquid leakage under high pressure is not a priority goal, resulting in a large amount of leakage during the operation of the seal, which reduces the equipment's conveying efficiency, increases operating costs, and in severe cases causes environmental pollution, and even endangers property and personal safety.

[0003] How to solve the above technical problems and ensure that the friction torque of the sealing end face is small under high pressure and reduce the occurrence of liquid leakage is the research direction that technical personnel in this field are committed to. Summary of the invention

[0004] The object of the present invention is to provide a micro-leakage reverse reflux type high-pressure mechanical sealing device to solve the problems raised by the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A micro-leakage reverse reflux type high-pressure mechanical sealing device, comprising a sleeve ring seat, a sealing gland, a pre-installed ring, a rotating fixed ring, a high-pressure sealing assembly, a rotating sealing ring, a stationary sealing ring, a stationary ring seat, and a supporting spring. The sleeve ring seat is penetrated by a main shaft, the rotating fixed ring is fixedly installed on one end of the sleeve ring seat, the sealing gland is fixedly connected to a pump connector, and the pre-installed ring is fixedly connected to the sealing gland, wherein:

[0007] The sleeve ring seat is provided with a first notch, and the rotating sealing ring is sleeved on the sleeve ring seat and located in the first notch; the stationary ring seat is provided with a second notch on the side facing the rotating sealing ring, and the stationary sealing ring is sleeved on the sleeve ring seat and located in the second notch; the sealing gland is provided with a third notch for installing a supporting spring, one end of the supporting spring is installed in the third notch, and the other end is connected to the stationary ring seat, so that the rotating sealing ring abuts against the stationary sealing ring through the supporting spring;

[0008] The high-pressure sealing assembly is arranged between the rotating sealing ring and the sleeve ring seat, and between the stationary sealing ring and the stationary ring seat. The high-pressure sealing assembly consists of U-shaped sealing rings and O-shaped sealing rings of unequal thickness. The O-shaped sealing rings are sleeved in the U-shaped grooves of the U-shaped sealing rings of unequal thickness, and the two side edges of the O-shaped sealing rings are tightly attached to the inner wall of the U-shaped sealing groove.

[0009] As a specific implementation method, slot one and slot two are both provided with a receiving groove for installing a high-pressure sealing assembly, and the thickness of the unequal thickness U-shaped sealing ring away from the receiving groove is greater than the thickness on the side close to the receiving groove; the outer end surfaces on both sides of the unequal thickness U-shaped sealing ring are provided with inwardly recessed trapezoidal grooves, and there are multiple trapezoidal grooves on the outer end surface of each side, which are evenly spaced along the radial direction on the outer end surface of the U-shaped sealing ring.

[0010] As a specific implementation, a group of reverse reflux grooves and a group of forward injection grooves are provided on the ring end surface of the rotating sealing ring facing the stationary sealing ring, and the forward injection grooves are located outside the reverse reflux grooves;

[0011] There are multiple reverse reflux grooves, which are arranged in a spiral shape on the end face of the rotating sealing ring. The inner circle radius of the reverse reflux groove is not less than the inner diameter value of the stationary sealing ring, and the outer circle radius is less than the outer diameter value of the stationary sealing ring; the forward injection groove is in the shape of a bull horn, and the tip of the bull horn faces outward, the position of the tip of the bull horn exceeds the outer edge of the stationary sealing ring, and the position of the open end of the bull horn is located on the inner side of the outer edge of the stationary sealing ring.

[0012] As a specific implementation manner, the number of the reverse reflux grooves is 6-18, the depth is 4μm-12μm, and all the reverse reflux grooves are evenly spaced along the same circumferential direction; the number of the forward injection grooves is 3-8, the depth is 0.4mm-1.2mm, and all the forward injection grooves are evenly spaced along the same circumferential direction.

[0013] As a specific implementation manner, the U-shaped sealing rings of unequal thickness are made of plastic or rubber.

[0014] As a specific implementation, a leakage hole is provided on the side of the sealing gland facing away from the pump connecting body, and a throttling liquid-blocking ring is fixedly installed on the outer side of the leakage hole for collecting the leaked liquid.

[0015] As a specific implementation, the side of the stationary ring seat facing away from the stationary sealing ring is sealed with the sealing cover through a retaining ring and a balancing sealing ring. The retaining ring and the balancing sealing ring are inserted between the stationary ring seat and the sealing cover, and the retaining ring is close to the sealing cover side, and the balancing sealing ring is close to the stationary ring seat side.

[0016] As a specific implementation, a flushing hole is provided on the sealing gland, and a liquid diversion ring is fixedly installed on the inner side of the sealing gland at the flushing hole.

[0017] As a specific implementation, an annular groove is provided on the radial outer side wall of the pre-installation ring, and an annular boss matching with the annular groove is provided on the rotating fixed ring.

[0018] As a specific implementation manner, an elastic metal sheet is arranged inside the U-shaped sealing ring of unequal thickness.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The sealing device of the present invention has high-pressure sealing components arranged between the rotating sealing ring and the sleeve ring seat, and between the stationary sealing ring and the stationary ring seat. The O-shaped sealing ring is protected by the U-shaped sealing ring of unequal thickness, thereby increasing the sealing strength and preventing the O-shaped sealing ring from being compressed, extruded and bursting under high pressure. At the same time, the lips of the U-shaped ring of unequal thickness are compressed and supported by the elastic force of the O-shaped ring, so that the lips are always in close contact with the sealed surface, thereby ensuring the sealing effect under high pressure.

[0021] 2. A groove structure combining a millimeter-level forward injection groove and a micron-level reverse reflux groove is set on the sealing end face of the rotating sealing ring. During the operation of the sealing device, high-pressure liquid can be introduced into the sealing end face for lubrication through the forward injection groove, and possible leakage liquid can be pumped back to the high-pressure area through the rotary pumping effect of the micron-level reverse reflux groove, thereby achieving the purpose of autonomously enhancing lubrication and controlling leakage of the sealing operating end face under high pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of the micro-leakage reverse reflux type high-pressure mechanical sealing device of the present invention;

[0023] Figure 2 It is a cross-sectional view of the high-pressure sealing component in a free state;

[0024] Figure 3 for Figure 1 A partial enlarged view of the middle I position;

[0025] Figure 4 for Figure 1 A partial enlarged view of the II position;

[0026] Figure 5 This is the sealing end face groove structure diagram;

[0027] Figure 6 It is a cross-sectional view of a high-pressure sealing component containing an elastic metal sheet in a free state;

[0028] In the figure: 1. sleeve ring seat; 2. high-pressure sealing assembly; 3. rotating sealing ring; 4. retaining ring; 5. liquid diversion ring; 6. stationary sealing ring; 7. stationary ring seat; 8. support spring; 9. pre-installed ring; 10. retaining ring; 11. balancing sealing ring; 12. rotating fixed ring; 13. throttling liquid retaining ring; 14. sealing cover; 101. notch one; 102. accommodating groove; 201. U-shaped sealing ring of unequal thickness; 202. O-ring; 203. trapezoidal groove; 204. elastic metal sheet; 301. reverse reflux groove; 302. forward injection groove; 141. flushing hole; 142. leakage hole; 701. notch two. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in an exemplary manner in conjunction with the accompanying drawings.

[0030] It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0031] In addition, in the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. However, if it is indicated as a direct connection, it means that the two connected bodies are not connected through a transition structure, but are connected to form a whole through a connecting structure. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, the first feature "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0034] The present invention provides a micro-leakage reverse reflux type high pressure mechanical sealing device, see Figure 1 As shown, the sealing device includes a sleeve ring seat 1, a sealing cover 14, a pre-installed ring 9, a rotating fixed ring 12, a high-pressure sealing assembly 2, a rotating sealing ring 3, a stationary sealing ring 5, a stationary ring seat 7 and a supporting spring 8.

[0035] The sleeve ring seat 1 has a main shaft running through it, a rotating fixed ring 12 is fixedly mounted on one end of the sleeve ring seat 1, a sealing gland 14 is fixedly connected to the pump connection body, and a pre-installed ring 9 is fixedly connected to the sealing gland 14. In this example, the sealing gland 14 is fixedly connected to the pump connection body by a bolt assembly; the rotating fixed ring 12 is fixedly connected to the sealing gland 14 by a bolt assembly. Here, as Figure 1As shown, the main shaft is horizontally arranged in the left-right direction, with the right side being the atmospheric side and the left side being the medium side of the pump chamber. The sleeve ring seat 1 rotates relative to the sealing gland 14 as the main shaft rotates, and the rotating fixed ring 12 is fixedly installed on the right side of the sleeve ring seat 1 and rotates as the main shaft rotates. The sealing device integrates the sleeve ring seat 1 and the sealing gland 14 as a whole through the pre-installed ring 9 and the rotating fixed ring 12. Specifically, in this example, an annular groove is provided on the radial outer wall of the pre-installed ring 9, and an annular boss matching the annular groove is provided on the rotating fixed ring 12. The groove width of the annular groove is larger than the width of the annular boss. The purpose is to limit the rotating fixed ring 12 when it is installed. After the rotating fixed ring 12 is installed, the pre-installed ring 9 will be removed.

[0036] Preferably, in this example, the rotating seal ring 3 can be axially limited and fixed on the sleeve ring seat 1 by the clamp ring 4; the stationary seal ring 5 is axially limited and fixed on the stationary ring seat 7 by screws. In addition, the stationary seal ring 5 is radially matched and installed on the sealing gland 14.

[0037] In this example, a slot 101 is provided on the sleeve ring seat 1, and the rotating sealing ring 3 is sleeved on the sleeve ring seat 1 and located in the slot 101; a slot 2 701 is provided on the side of the stationary ring seat 7 facing the rotating sealing ring 3, and the stationary sealing ring 5 is sleeved on the sleeve ring seat 1 and located in the slot 2 701, and a slot 3 for installing a support spring 8 is provided on the sealing cover 14, one end of the support spring 8 is installed in the slot 3, and the other end is connected to the stationary ring seat 7, and the compressive elastic force generated by the support spring 8 makes the stationary sealing ring 5 in the stationary ring seat 7 fit tightly with the rotating sealing ring 3 on its left side.

[0038] Here, a high pressure sealing assembly 2 is arranged between the rotating sealing ring 3 and the sleeve ring seat 1, and between the stationary sealing ring 5 and the stationary ring seat 7. The high pressure sealing assembly 2 is composed of a U-shaped sealing ring 201 of unequal thickness and an O-shaped sealing ring 202. The O-shaped sealing ring is sleeved in the U-shaped groove of the U-shaped sealing ring 201 of unequal thickness, and the two sides of the O-shaped sealing ring 202 are closely attached to the inner wall of the U-shaped sealing groove, see Figure 2 shown.

[0039] Specifically, the bottom of the notch 101 on the sleeve ring seat 1 and the notch 2 701 on the stationary ring seat 7 are both provided with a receiving groove 102 for installing the high-pressure sealing assembly 2, and the thickness of the unequal thickness U-shaped sealing ring 201 away from the receiving groove 102 is greater than the thickness of the side close to the receiving groove 102. That is, the unequal thickness U-shaped sealing ring 201 in the notch 101 has a thicker thickness on the side in contact with the rotating sealing ring 3; the unequal thickness U-shaped sealing ring 201 in the notch 2 701 has a thicker thickness on the side in contact with the stationary sealing ring 5, see Figure 3 , 4In addition, both sides of the outer end surface of the unequal thickness U-shaped sealing ring 201 are provided with inwardly recessed trapezoidal grooves 203, and there are multiple trapezoidal grooves 203 on each side of the outer end surface, which are evenly spaced along the radial direction of the main shaft. By providing the trapezoidal grooves 203, after the unequal thickness U-shaped sealing ring 201 is compressed and deformed, it can ensure that the lip of the unequal thickness U-shaped sealing ring 201 is flat and in close contact with the sealed parts such as the rotating sealing ring 3 and the stationary sealing ring 5.

[0040] Preferably, the unequal thickness U-shaped sealing ring 201 is made of plastic or rubber material with good elasticity. In order to enhance the strength and deformation force of the unequal thickness U-shaped sealing ring 201, an elastic metal sheet 204 may be added inside the unequal thickness U-shaped sealing ring 201. Figure 6 shown.

[0041] A retaining ring 10 and a balancing sealing ring 11 are also provided between the stationary ring seat 7 and the sealing cover 14. The retaining ring 10 and the balancing sealing ring 11 are in contact with and are sleeved between the stationary ring seat 7 and the sealing cover 14. The retaining ring 10 is close to the sealing cover 14 side, and the balancing sealing ring 11 is close to the stationary ring seat 7 side.

[0042] In addition, a group of reverse reflux grooves 301 and a group of forward injection grooves 302 are provided on the ring end surface of the rotating sealing ring 3 facing the stationary sealing ring 5. There are multiple forward injection grooves 302, which are evenly spaced along the same circumferential direction; there are multiple reverse reflux grooves 301, which are located on the inner side of the forward injection grooves 302, and the multiple reverse reflux grooves 301 are also evenly spaced along the same circumferential direction. Figure 5 shown.

[0043] A plurality of reverse reflux grooves 301 are arranged in a spiral shape on the end face of the rotating sealing ring 3. The longitudinal cross section of each reverse reflux groove 301 is in a rhombus shape. The inner circle radius of the reverse reflux groove 301 is not less than the inner diameter of the stationary sealing ring 5, and the outer circle radius is less than the outer diameter of the stationary sealing ring 5. Each forward injection groove 302 is in a bull horn shape, with the tip of the bull horn facing outward, the position of the tip of the bull horn exceeds the outer edge of the stationary sealing ring 5, and the position of the open end of the bull horn is located inside the outer edge of the stationary sealing ring 5. In this example, all the reverse reflux grooves 301 are arranged in a clockwise spiral shape on the end face of the rotating sealing ring 3.

[0044] During the rotation of the rotating sealing ring 3, high-pressure liquid is introduced into between the rotating sealing ring 3 and the stationary sealing ring 6 through the forward injection groove 302, so as to lubricate and cool the two end surfaces of relative motion, and the high-pressure liquid flows from the outer diameter high-pressure side to the inner diameter low-pressure side of the stationary sealing ring 6 at the dynamic sealing end face, which will cause a small amount of liquid leakage along the flow direction. During the leakage process, due to the spiral shape formed by the reverse reflux groove 301, the leaked liquid will flow back from the inner diameter low-pressure side of the stationary sealing ring 6 to the outer diameter high-pressure side through the dynamic pressure effect generated by the reverse reflux groove 301, thereby avoiding the leakage of high-pressure liquid.

[0045] In addition, in this example, the number of the reverse reflux grooves 301 is 6-18, and the depth is 4μm-12μm; the forward injection grooves 302 are evenly distributed along the end surface axial direction, the number is 3-8, and the depth is 0.4mm-1.2mm. Figure 5 As shown, the number of reverse reflux grooves 301 is 12, the number of forward injection grooves 302 is 6, and two reverse reflux grooves 301 are arranged between two adjacent forward injection grooves 302. Here, the depth design of the reverse reflux groove 301 is to enable the leaked liquid to quickly return to the high-pressure side according to the dynamic pressure effect generated by the reverse reflux groove 301 after entering the reverse reflux groove 301, and prevent the liquid from entering the rotating sealing ring 3. If the depth of the forward injection groove 302 is too small, it will be unfavorable for the introduction of high-pressure liquid, and if it is too large, it will lead to excessive high-pressure liquid between the rotating sealing ring 3 and the stationary sealing ring 6, and the reverse reflux groove 301 will not have time to reversely return it to the high-pressure side, resulting in the high-pressure liquid flowing into the rotating sealing ring 3.

[0046] In addition, a leakage hole 142 is provided on the side of the sealing gland 14 facing away from the pump connection body, see Figure 1 As shown, a throttling liquid-blocking ring 13 is fixedly installed on the outer side of the leakage hole 142, i.e., close to the atmosphere side, for collecting the leaked liquid and preventing the leaked liquid from directly flowing into the atmosphere when abnormal leakage occurs in the sealing device.

[0047] The sealing gland 14 is also provided with a flushing hole 141, see Figure 1 As shown, a liquid diversion ring 5 is fixedly installed on the inner side of the sealing gland 14 at the flushing hole 141. The flushing hole 141 is provided to introduce high-pressure fluid to flush the dynamic sealing end face, to prevent impurities on the medium side of the pump chamber from entering the sealing end face, and to cool down the temperature at the same time, and the liquid diversion ring 5 is provided to prevent the introduced high-pressure fluid from directly flushing the sealing end face.

[0048] The operating principle of the micro-leakage reverse reflux type high-pressure mechanical sealing device of the present invention is as follows:

[0049] The micro-leakage reverse reflux type high-pressure mechanical seal device is fixed to the pump connector by bolts, and the inner diameter of the sleeve ring seat 1 is installed in cooperation with the main shaft, and is fixed to the main shaft by the rotating fixed ring 12; after installation, the pre-installed ring 9 is removed to complete the installation. During the operation of the sealing device, the medium side of the pump chamber is filled with high-pressure liquid. Under the action of the high-pressure liquid, the bottom end face of the rotating seal ring 3 presses the high-pressure seal assembly 2, so that the O-ring 201 is compressed and deformed, ensuring that the outer end faces of the lips on both sides of the unequal thickness U-shaped seal ring 202 are tightly attached to the sleeve ring seat 1 and the rotating seal ring 3, thereby forming a sealing effect on the high-pressure liquid; the sealing principle of the high-pressure seal assembly between the stationary seal ring 6 and the stationary ring seat 7 is also the same, and the stationary ring seat 7 and the seal gland 14 are sealed by the balance seal ring 11 to prevent the high-pressure liquid from leaking from here to the atmosphere side. The main function of the retaining ring 10 is to prevent the seal ring 11 from being squeezed out of the gap between the stationary ring seat 7 and the seal gland 14 by the high-pressure liquid. At the same time, the sleeve ring seat 1 drives the rotating sealing ring 3 to rotate with the main shaft, and the end face of the stationary sealing ring 6 is closely attached to the end face of the rotating sealing ring 3 under the action of the high-pressure liquid and the supporting spring 8, so as to generate relative motion and form a dynamic sealing end face; during the rotation of the rotating sealing ring 3, the high-pressure liquid is introduced into between the rotating sealing ring 3 and the stationary sealing ring 6 through the forward injection groove 302, so as to lubricate and cool the two end faces of relative motion, and the high-pressure liquid flows from the outer diameter high-pressure side of the stationary sealing ring 6 to the inner diameter low-pressure side at the dynamic sealing end face, which will cause a small amount of liquid leakage along the flow direction. During the leakage process, the leaked liquid will flow back from the inner diameter low-pressure side of the stationary sealing ring 6 to the outer diameter high-pressure side through the dynamic pressure effect generated by the reverse reflux groove 301, so as to avoid the leakage of the high-pressure liquid.

[0050] The present invention introduces a small amount of high-pressure liquid into the sealing end face to increase lubrication. At the same time, the micro-leakage generated by the sealing end face flows back to the high-pressure area, which can reduce the wear of the sealing end face and control the sealing leakage. While ensuring the service life of the seal, the sealing performance under high-pressure conditions is also greatly improved.

[0051] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A micro-leakage reverse reflux type high-pressure mechanical sealing device, characterized in that: It includes a sleeve ring seat, a sealing gland, a pre-installed ring, a rotating fixed ring, a high-pressure sealing assembly, a rotating sealing ring, a stationary sealing ring, a stationary ring seat, and a supporting spring. The sleeve ring seat has a main shaft running through it. The rotating fixed ring is fixedly installed on one end of the sleeve ring seat. The sealing gland is fixedly connected to the pump connector. The pre-installed ring is fixedly connected to the sealing gland, wherein: The sleeve ring seat is provided with a first notch, and the rotating sealing ring is sleeved on the sleeve ring seat and located in the first notch; the stationary ring seat is provided with a second notch on the side facing the rotating sealing ring, and the stationary sealing ring is sleeved on the sleeve ring seat and located in the second notch; the sealing gland is provided with a third notch for installing a supporting spring, one end of the supporting spring is installed in the third notch, and the other end is connected to the stationary ring seat, so that the rotating sealing ring abuts against the stationary sealing ring through the supporting spring; The high-pressure sealing assembly is arranged between the rotating sealing ring and the sleeve ring seat, and between the stationary sealing ring and the stationary ring seat. The high-pressure sealing assembly is composed of a U-shaped sealing ring of unequal thickness and an O-shaped sealing ring. The O-shaped sealing ring is sleeved in the U-shaped groove of the U-shaped sealing ring of unequal thickness, and the two sides of the O-shaped sealing ring are tightly attached to the inner wall of the U-shaped groove. The slots 1 and 2 are both provided with receiving grooves for installing the high-pressure sealing assembly, and the thickness of the unequal thickness U-shaped sealing ring away from the receiving groove is greater than the thickness of the side close to the receiving groove; the outer end surfaces of both sides of the unequal thickness U-shaped sealing ring are provided with inwardly recessed trapezoidal grooves, and there are multiple trapezoidal grooves on the outer end surface of each side, which are evenly spaced along the radial direction and arranged on the outer end surface of the U-shaped sealing ring; A set of reverse reflux grooves and a set of forward injection grooves are provided on the end surface of the rotating sealing ring facing the stationary sealing ring. The forward injection grooves are located outside the reverse reflux grooves. High-pressure liquid is introduced into between the rotating sealing ring and the stationary sealing ring through the forward injection grooves. The leaked liquid flows back from the inner diameter low-pressure side of the stationary sealing ring to the outer diameter high-pressure side through the reverse reflux grooves. A plurality of reverse reflux grooves are arranged in a spiral shape on the end face of the rotating sealing ring, the inner circle radius of the reverse reflux groove is not less than the inner diameter value of the stationary sealing ring, and the outer circle radius is less than the outer diameter value of the stationary sealing ring; the forward injection groove is in the shape of a bull horn, with the tip of the bull horn facing outward, the position of the tip of the bull horn exceeds the outer edge of the stationary sealing ring, and the position of the open end of the bull horn is located on the inner side of the outer edge of the stationary sealing ring, the number of the reverse reflux grooves is 6-18, the depth is 4μm-12μm, and all the reverse reflux grooves are evenly spaced along the same circumferential direction; the number of the forward injection grooves is 3-8, the depth is 0.4mm-1.2mm, and all the forward injection grooves are evenly spaced along the same circumferential direction.

2. A micro-leakage reverse reflux high-pressure mechanical sealing device according to claim 1, characterized in that: The U-shaped sealing rings of different thickness are made of plastic or rubber.

3. A micro-leakage reverse reflux type high-pressure mechanical sealing device according to claim 1, characterized in that: A leakage hole is provided on the side of the sealing gland facing away from the pump connecting body, and a throttling liquid-blocking ring is fixedly installed on the outer side of the leakage hole for collecting the leaked liquid.

4. A micro-leakage reverse reflux type high-pressure mechanical sealing device according to claim 1, characterized in that: The side of the stationary ring seat away from the stationary sealing ring is sealed with the sealing cover through a retaining ring and a balancing sealing ring. The retaining ring and the balancing sealing ring are sleeved between the stationary ring seat and the sealing cover, and the retaining ring is close to the sealing cover side, and the balancing sealing ring is close to the stationary ring seat side.

5. A micro-leakage reverse reflux type high-pressure mechanical sealing device according to claim 1, characterized in that: A flushing hole is provided on the sealing gland, and a liquid diversion ring is fixedly installed on the inner side of the sealing gland at the flushing hole.

6. A micro-leakage reverse reflux type high-pressure mechanical sealing device according to claim 1, characterized in that: The pre-installation ring is provided with an annular groove, and the rotating fixed ring is provided with an annular boss matched with the annular groove.

7. A micro-leakage reverse reflux type high-pressure mechanical seal device according to claim 1, characterized in that: An elastic metal sheet is arranged inside the U-shaped sealing ring of unequal thickness.

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