An ultra-high pressure zero leakage mechanical seal end face structure

Abstract

An ultra-high pressure zero leakage mechanical seal end face structure, including a dynamic ring and a static ring of a mechanical seal, one side of the dynamic ring or static ring end face is a high pressure side, i.e., upstream, and the other side of the dynamic ring or static ring end face is a low pressure side, i.e., downstream, and the end face of one of the dynamic ring or static ring is divided into five functional structural areas, which are distributed in the annular band area of ​​the seal end face and are, from the downstream side to the upstream side, a sealing dam area, a guide functional structural area, a low pressure leakage control functional structural area, an isolation functional structural area, and a high pressure bearing functional structural area. The guide, low pressure leakage control, and isolation functional structural areas are composed of a combination of circumferential steps, micro-textures, and annular grooves, wherein the guide functional structural area has a radial straight groove connecting the low pressure leakage control, isolation, high pressure bearing functional structural area, and the upstream side, and the high pressure bearing functional structural area is a conical surface configuration, and between the guide, low pressure leakage control, and isolation functional structural areas is a sealing dam. The beneficial effect of the present invention is that under the influence of the guiding structure and the isolation structure functions, a low-pressure area surrounding the sealing end surface can be generated in the low-pressure leakage control functional structure area to form a strong throttling effect, thereby overcoming the ultra-high pressure difference resistance, and at the same time, the upstream side cone surface configuration produces a strong fluid static pressure effect, so that the seal operates in a non-contact state. The invention can be used for liquid, gas or gas-liquid mixed phase medium, and it is easy to achieve zero leakage and non-contact operation under ultra-high pressure conditions, and has a long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical end face sealing, and in particular to a zero-leakage sealing end face groove structure suitable for ultra-high liquid or gas pressure, and suitable for a rotary shaft end sealing device of fluid machinery such as pumps and compressors. Background Art

[0002] In the existing field of mechanical end face sealing technology, in order to prevent the leakage of high-pressure fluid along the rotating shaft, a multi-stage seal series is often used. For example, a three-stage series fluid dynamic pressure type mechanical seal achieves sealing through three-stage pressure separation, or firstly uses a fluid static pressure type mechanical seal to basically complete the pressure relief, and further uses the second and third stage seals to prevent leakage under low pressure to achieve sealing. The above two methods are typical forms of nuclear main pump mechanical seals. The fluid pressure is about 16MPa. For higher fluid pressures such as 30MPa, this method further increases the number of sealing stages, which not only reduces the efficiency of the whole machine, but also is not conducive to the integration and lightweight development of the whole machine. In addition, Salant et al. opened a cavity inside the static ring of the fluid static pressure type mechanical seal to fill it with pressurized fluid, in order to control the deformation of the ring body by changing the fluid pressure, thereby regulating the thickness of the sealing liquid film to control the leakage. Since a too small balance gap will lead to increased end face contact and friction and wear, the method proposed by Salant et al. still does not overcome the characteristics of large leakage of fluid static pressure type mechanical seals. Therefore, in the field of mechanical sealing technology, due to the inability to effectively control the strong pressure differential flow caused by the ultra-high fluid pressure, there is still a lack of effective leakage control methods for ultra-high pressure fluids. Summary of the invention

[0003] In order to control the strong pressure differential flow caused by ultra-high fluid pressure, overcome the deficiency of existing mechanical end face sealing technology that cannot effectively control the sealing leakage, and at the same time improve the sealing tribological performance and ensure the sealing load-bearing performance, the present invention provides an ultra-high pressure zero leakage mechanical seal end face structure, which can effectively balance the strong pressure differential flow of ultra-high pressure fluid under single-stage sealing, achieve zero leakage, and make the mechanical seal have good tribological performance and load-bearing performance.

[0004] The technical solution of the present invention:

[0005] An ultra-high pressure zero leakage mechanical seal end face structure, including a dynamic ring and a static ring of a mechanical seal, one side of the dynamic ring or static ring end face is a high pressure side, i.e., upstream, and the other side of the dynamic ring or static ring end face is a low pressure side, i.e., downstream, and the end face of one of the dynamic ring or static ring is divided into five functional structural areas, which are distributed in the annular band area of ​​the seal end face and are, from the downstream side to the upstream side, a sealing dam area, a guide functional structural area, a low pressure leakage control functional structural area, an isolation functional structural area, and a high pressure bearing functional structural area. The guide, low pressure leakage control, and isolation functional structural areas are composed of a combination of circumferential steps, micro-textures, and annular grooves, wherein the guide functional structural area has a radial straight groove connecting the low pressure leakage control, isolation, high pressure bearing functional structural area, and the upstream side, and the high pressure bearing functional structural area is a conical surface configuration, and between the guide, low pressure leakage control, and isolation functional structural areas is a sealing dam.

[0006] Furthermore, the guide functional structural area is composed of three parts, the first part is a periodically distributed micro-texture or circumferential step, the number of which is in the range of 1 to 100; the second part is an annular groove; the third part is a periodically distributed radial linear groove and is connected to the upstream side, the number of which is in the range of 2 to 10, the depth is in the range of 5 to 1000 μm, and the central angle of the groove area is in the range of 1 to 10°. The micro-texture or circumferential step of the first part can be connected to the annular groove of the second part or the radial linear groove of the third part in a divergent shape.

[0007] Furthermore, the low-pressure leakage control and isolation functional structural areas are composed of periodically distributed circumferential steps, which are paired and connected with the radial straight grooves one by one to form divergent grooves, that is, the number of periods of the two is the same, and the depth range is 1 to 200 μm, and the width range is 0.1 to 8 mm; or the low-pressure leakage control and isolation functional structural areas are composed of micro-textures and annular grooves, and 2 to 20 micro-textures are distributed between every two radial straight grooves and are connected with the annular grooves.

[0008] Furthermore, the annular grooves are all connected with the radial linear grooves. The depth of the annular grooves in the guide and isolation functional structural area is 0 to 500 μm, and the depth of the annular grooves in the low-pressure leakage control functional structural area is 1 to 500 μm. The width range is 0.1 to 5 mm.

[0009] Furthermore, the micro texture is in the shape of long strips such as but not limited to long trapezoidal, rectangular, L-shaped, parallelogram and the like. For the guiding functional structure area and the isolation functional structure area, the depth of the micro texture ranges from 0 to 100 μm, and for the low-voltage leakage control functional structure area, the depth ranges from 1 to 100 μm.

[0010] Furthermore, the high-voltage bearing functional structural area is composed of periodically distributed conical surfaces, the number of periods is the same as that of the radial linear grooves, and the cone angle range is 1 to 1000 μrad.

[0011] Working principle of the present invention:

[0012] Under the action of fluid pressure differential force and the rotary shear of the sealing dynamic ring, the high-pressure fluid on the upstream side is sucked into the gap of the sealing end face. The fluid first enters the high-pressure bearing functional structural area, and forms a strong fluid static pressure effect and a pressure fluid film under the action of the conical surface configuration. This is the main reason for the sealing bearing capacity. The ultra-high pressure difference between the inner and outer diameters causes the fluid to flow further to the downstream side. The texture of the isolation functional structural area is a divergent gap. The fluid pressure in this area is low and stable, so that the fluid flow in the high-pressure bearing functional structural area has little effect on the fluid flow in the low-pressure leakage control functional structural area. At the same time, the divergent texture of the guiding functional structural area makes the fluid pressure in this area lower than that on the downstream side, which can form a reverse pressure differential flow to reduce leakage. The low-pressure leakage control functional structure area is between the isolation and guide functional structure areas, making it a relatively closed area, and the fluid pressure around this area is relatively low. This makes the texture of the low-pressure leakage control functional area extremely low in fluid pressure due to its divergence, forming a significant pressure difference flow that makes the surrounding fluid flow to this area. Further, due to the obstruction of the sealing dam area, the fluid in this area flows to the upstream side through the radial straight groove of the guide functional structure area to achieve zero leakage sealing.

[0013] Beneficial effects of the present invention:

[0014] (1) Based on the principle of fluid mechanics, the present invention divides the sealing end face into five functional structural areas. By constructing a reverse pressure differential flow to balance the strong pressure differential flow caused by the ultra-high fluid pressure, a single-stage seal can control the sealing of the ultra-high pressure fluid and achieve zero leakage.

[0015] (2) The presence of the isolation, low-pressure leakage control and guide functional structural areas in the present invention enables the seal to achieve zero leakage under a larger balance gap, so that the seal not only has good sealing performance, but also has excellent tribological properties.

[0016] (3) The present invention can be applied to the sealing of high-pressure or ultra-high-pressure liquid, gas or gas-liquid mixed medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the mechanical seal end face structure of the present invention, in which 1 is a sealing dam, 21, 22 and 23 are L-shaped textures, annular grooves and radial straight grooves which together constitute a guiding functional structural area, 3 is a low-pressure leakage control functional structural area composed of divergent circumferential step-shaped grooves, 41 and 42 are isolation functional structural areas composed of long trapezoidal textures and annular grooves, and 5 is a conical surface configuration, i.e., a high-pressure bearing functional structural area.

[0018] Figure 2 for Figure 1 Schematic diagram of the cross section of the middle sealing ring AA.

[0019] Figure 3Another embodiment of the mechanical seal groove end face of the present invention is shown in FIG. Figure 1 The micro-texture of the guiding functional structure area adopts a long trapezoidal texture.

[0020] Figure 4 Another embodiment of the mechanical seal groove end face of the present invention is shown in FIG. Figure 1 The microtexture of the isolation functional structure area adopts L-type texture.

[0021] Figure 5 Another embodiment of the mechanical seal groove end face of the present invention is shown in FIG. Figure 3 , the depth of the annular groove in the guiding and isolation functional structure area is zero.

[0022] Figure 6 Another embodiment of the mechanical seal groove end face of the present invention is shown in FIG. Figure 1 The low-pressure leakage control functional structure area is composed of an L-shaped divergent microtexture and an annular groove, and the isolation functional structure area is composed of only an annular groove, that is, the microtexture depth is zero. Specific implementation plan

[0023] Reference Figure 1-6 , an ultra-high pressure zero leakage mechanical seal end face structure, including a dynamic ring and a static ring of a mechanical seal, one side of the dynamic ring or static ring end face is a high pressure side, i.e., upstream, and the other side of the dynamic ring or static ring end face is a low pressure side, i.e., downstream, and the end face of one of the dynamic ring or static ring is divided into five functional structural areas 1-5, which are distributed in an annular area of ​​the sealing end face and are, from the downstream side to the upstream side, a sealing dam area 1, a guide functional structural area 2 (21, 22 and 23), a low pressure leakage control functional structural area 3, an isolation functional structural area 4 (41 and 42) and a high pressure bearing functional structural area 5. The guiding, low-pressure leakage control and isolation functional structural areas 2, 3 and 4 are composed of a combination of circumferential steps, micro-textures and annular grooves, wherein the guiding functional structural area 2 has a radial straight groove 23 connecting the low-pressure leakage control, isolation, high-pressure bearing functional structural areas 3, 4, 5 and the upstream side, and the high-pressure bearing functional structural area 5 is a conical surface configuration 5, and there is a sealing weir between the guiding, low-pressure leakage control and isolation functional structural areas 2, 3 and 4.

[0024] The guide functional structural area 2 is composed of three parts. The first part is a periodically distributed micro-texture or circumferential step 21, and its period number ranges from 1 to 100; the second part is an annular groove 22; the third part is a periodically distributed radial linear groove 23 and is connected to the upstream side, and its period number ranges from 2 to 10, the depth ranges from 5 to 1000 μm, and the central angle range of the groove area is 1 to 10°. The first part of the micro-texture or circumferential step 21 can be connected with the second part of the annular groove 22 or the third part of the radial linear groove 23 in a divergent shape.

[0025] The low-pressure leakage control and isolation functional structural areas 3 and 4 are both composed of periodically distributed circumferential steps 3, which are paired and connected with the radial straight grooves 23 one by one to form divergent grooves, that is, the number of periods of the two is the same, and the depth range is 1 to 200 μm and the width range is 0.1 to 8 mm; or the low-pressure leakage control and isolation functional structural areas 3 and 4 are both composed of micro-textures 41 and annular grooves 42, and 2 to 20 micro-textures 41 are evenly distributed between every two radial straight grooves 23 and connected with the annular grooves 42.

[0026] The annular grooves 22 and 42 are both connected with the radial linear grooves 23. For the guide and isolation functional structural areas 2 and 4, the depth range of the annular grooves 22 and 4 is 0 to 500 μm, and for the low-pressure leakage control functional structural area 3, the depth range is 1 to 500 μm, and the width range is 0.1 to 5 mm.

[0027] The micro textures 21, 41 are in the shape of long strips such as but not limited to long trapezoidal, rectangular, L-shaped, parallelogram and the like. For the guiding functional structure area 2 and the isolation functional structure area 4, the depth range of the micro textures 21, 41 is 0 to 100 μm, and for the low-pressure leakage control functional structure area, the depth range is 1 to 100 μm.

[0028] The high-voltage bearing functional structural area 5 is composed of periodically distributed conical surfaces 5 , the number of periods of which is the same as that of the radial linear grooves 23 , and the cone angle range is 1 to 1000 μrad.

[0029] Reference Figure 1 Under the action of fluid pressure differential force and the rotational shear of the sealing dynamic ring, the high-pressure fluid on the upstream side is sucked into the gap of the sealing end face. The fluid first enters the high-pressure bearing functional structural area 5, and forms a strong fluid static pressure effect and a pressure fluid film under the action of the conical surface configuration 5, which is the main reason for the sealing bearing capacity. The ultra-high pressure difference between the inner and outer diameters causes the fluid to flow further to the downstream side. The texture of the isolation functional structural area 4 is a divergent gap. The fluid pressure in this area is low and stable, so that the fluid flow in the high-pressure bearing functional structural area 5 has little effect on the fluid flow in the low-pressure leakage control functional structural area 3. At the same time, the divergent texture of the guiding functional structural area 2 makes the fluid pressure in this area lower than that on the downstream side, which can form a reverse pressure differential flow to reduce leakage. The low-pressure leakage control functional structural area 3 is between the isolation and guide functional structural areas 4 and 2, making it a relatively closed area, and the fluid pressure around this area is relatively low. This makes the texture of the low-pressure leakage control functional area 3 extremely low in fluid pressure due to its divergence, forming a significant pressure difference flow that makes the surrounding fluid flow to this area. Further, due to the obstruction of the sealing dam area 1, the fluid in this area flows to the upstream side through the radial straight groove 23 of the guide functional structural area 2 to achieve zero leakage sealing.

[0030] The contents described in the embodiments of this specification are merely an enumeration of implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the inventive concept.

Claims

1. An ultra-high pressure zero leakage mechanical seal end face structure, comprising a dynamic ring and a static ring of a mechanical seal, wherein one side of the dynamic ring or static ring end face is a high pressure side, i.e., an upstream side, and the other side of the dynamic ring or static ring end face is a low pressure side, i.e., a downstream side, characterized in that: The end face of one of the dynamic ring or the static ring is divided into five functional structural areas, which are distributed in the annular belt area of ​​the sealing end face and are, from the downstream side to the upstream side, the sealing dam area, the guide functional structural area, the low-pressure leakage control functional structural area, the isolation functional structural area and the high-pressure bearing functional structural area; wherein the guide functional structural area has a radial straight groove connecting the low-pressure leakage control functional structural area, the isolation functional structural area, the high-pressure bearing functional structural area and the upstream side, the high-pressure bearing functional structural area is a conical surface configuration, and between the guide functional structural area, the low-pressure leakage control functional structural area and the isolation functional structural area is a sealing weir; The guide functional structural area is composed of three parts, the first part is the first micro texture which is distributed periodically, the second part is the first annular groove; the third part is the radial linear groove which is distributed periodically, and the first micro texture is connected with the radial linear groove through the first annular groove; The low-pressure leakage control functional structure area is composed of a second circumferential step that is periodically distributed, and the isolation functional structure area is composed of a second micro-texture and a second annular groove. There are 2 to 20 second micro-textures evenly distributed between every two radial straight grooves, and the second micro-texture is connected to the second annular groove, and the second annular groove is connected to the radial straight groove; the first micro-texture and the second micro-texture are in the shape of a long trapezoid, a rectangle, an L-shape or a parallelogram, and the number of periods of the cone surface is the same as the number of periods of the radial straight groove.

2. According to the ultra-high pressure zero leakage mechanical seal end face structure as described in claim 1, the period number range of the first part is 1 to 100; the period number range of the third part is 2 to 10, the depth range of the radial straight groove is 5 to 1000 μm, and the central angle range of the groove area of ​​the radial straight groove is 1 to 10°.

3. The ultra-high pressure zero leakage mechanical seal end face structure according to claim 1, wherein the depth of the radial linear groove ranges from 1 to 200 μm, and the width of the radial linear groove ranges from 0.1 to 8 mm. 4 . The ultra-high pressure zero leakage mechanical seal end face structure according to claim 1 , wherein the depth of the first annular groove and the second annular groove ranges from 0 to 500 μm. 5 . The ultra-high pressure zero leakage mechanical seal end face structure according to claim 1 , wherein the first micro texture and the second micro texture have a depth range of 0 to 100 μm.

6. The ultra-high pressure zero leakage mechanical seal end face structure according to claim 1, wherein the cone angle of the high pressure bearing functional structural area ranges from 1 to 1000 μrad.

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