A star wire dynamic pressure groove-back pressure self-induction enhanced pressurized dry gas seal structure

Abstract

The application relates to a star-shaped line dynamic pressure groove-back pressure self-induction reinforced pressurized dry gas seal structure and belongs to the technical field of rotary fluid machinery sealing. The sealing end surface of a dry gas seal dynamic ring is provided with main star-shaped line dynamic pressure grooves which are uniformly and interval arranged; the inner side direction of the main star-shaped line dynamic pressure grooves is provided with secondary star-shaped line dynamic pressure grooves; the secondary star-shaped line dynamic pressure grooves are uniformly and interval arranged along the circumferential direction of the dry gas seal dynamic ring; an annular pressure equalizing groove is arranged between the main star-shaped line dynamic pressure grooves and the secondary star-shaped line dynamic pressure grooves, the pressure equalizing groove is communicated with the secondary star-shaped line dynamic pressure grooves; and a back pressure induction hole is arranged in the pressure equalizing groove. The main and secondary star-shaped line dynamic pressure grooves are arranged in series in the gas flow direction, the groove roots of each star-shaped line dynamic pressure groove are provided with a sealing dam structure, the leakage can be effectively limited, the sealing back pressure is introduced into the dam area of the sealing gap through the back pressure induction hole, a secondary pressure peak is formed, and the radial pressure distribution of the gas film can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rotary fluid machinery sealing, in particular to a star-shaped line dynamic pressure groove-back pressure self-guiding flow reinforced pressurized dry gas seal structure BACKGROUND

[0002] Mechanical seal is a key technology to prevent fluid leakage, mainly applied to the dynamic and static interface of rotating shaft and cavity. Non-contact seal is widely used in various low-speed, medium-speed and high-speed rotating machinery due to its unique advantages. The main working principle of non-contact mechanical seal is to form a complete fluid film on the sealing end face by using fluid static pressure or dynamic pressure, so that the sealing end face is separated from each other, thereby avoiding contact, and having the characteristics of low leakage, low wear and long service life.

[0003] In recent years, dry gas seal technology has been constantly meeting the working condition requirements of supporting host machines, and with the rapid development of industry, the service environment of dry gas seal has gradually turned to extremization. The working conditions of high pressure inlet and high speed rotation have brought great challenges to the safe and stable operation of dry gas seal. In view of this, seal workers have carried out a large number of dry gas seal structure parameter optimization and fluid dynamic pressure groove type design research with the purpose of improving the end face gas film characteristics.

[0004] For the working environment of high pressure inlet, dry gas seal is in a high pressure heavy load state (high inlet pressure leads to high closing force) at the beginning of starting. The conventional groove type design and structure parameter optimization is to strengthen the fluid dynamic pressure effect of the sealing end flow field, and then to ensure the improvement of the load capacity in the stable operation stage of the seal. However, the initial stage of starting is low in sealing speed, and the fluid dynamic pressure effect is weak, which is the inherent defect of dynamic pressure type dry gas seal. Only groove type design and structure parameter optimization cannot produce enough gas film bearing capacity, and the separation of dynamic and static rings will be delayed, which will cause long time dry friction of the sealing end face and induce serious wear and large temperature rise of the end face. Therefore, in order to ensure the normal opening and long time stable operation of dry gas seal, a new type of high load dry gas seal structure needs to be proposed, which can ensure the long period operation of high parameter power system and enhance environmental protection. SUMMARY

[0005] In order to solve or partially solve the problems in the related art, the present application provides a star-shaped line dynamic pressure groove-back pressure self-guiding flow reinforced pressurized dry gas seal structure, which aims to solve the technical problems of poor gas film bearing capacity and slow opening speed of the existing dry gas seal structure in the extreme dry gas seal environment of high pressure and low speed.

[0006] The star-shaped line dynamic pressure groove-back pressure self-flowing enhanced pressurized dry gas seal structure comprises a dry gas seal ring, and a seal end surface of a dry gas seal moving ring is provided with a main star-shaped line dynamic pressure groove, which is uniformly and spacedly arranged along a circumferential direction of the dry gas seal moving ring, so that a main dynamic pressure groove platform area is formed between two adjacent main star-shaped line dynamic pressure grooves;

[0007] An inner side direction of the main star-shaped line dynamic pressure groove is provided with a secondary star-shaped line dynamic pressure groove, which is not connected with an inner side surface of the dry gas seal moving ring, so that a secondary seal dam is formed between the inner side surface of the dry gas seal moving ring and a groove root of the secondary star-shaped line dynamic pressure groove; the secondary star-shaped line dynamic pressure groove is uniformly and spacedly arranged along the circumferential direction of the dry gas seal moving ring, so that a secondary dynamic pressure groove platform area is formed between two adjacent secondary star-shaped line dynamic pressure grooves;

[0008] An annular pressure equalizing groove is arranged between the main star-shaped line dynamic pressure groove and the secondary star-shaped line dynamic pressure groove, the pressure equalizing groove is communicated with the secondary star-shaped line dynamic pressure groove and is not communicated with the main star-shaped line dynamic pressure groove, so that a main seal dam is formed between the pressure equalizing groove and a groove root of the main star-shaped line dynamic pressure groove;

[0009] A back pressure flow hole is arranged in the pressure equalizing groove, the back pressure flow hole penetrates the dry gas seal moving ring and corresponds to the secondary star-shaped line dynamic pressure groove one by one.

[0010] In some schemes, the main star-shaped line dynamic pressure groove has a main dynamic pressure groove root and two main groove area side walls located on both sides of the main dynamic pressure groove root;

[0011] The main dynamic pressure groove root is in a circular arc shape, and the two main groove area side walls extend along a star-shaped line.

[0012] In some schemes, the two main groove area side walls extend in the same direction or extend in opposite directions.

[0013] In some schemes, a parametric equation of the star-shaped line is as follows:

[0014] wherein a constant a is a radial width of the main star-shaped line dynamic pressure groove, and a constant b is 2a-3a.

[0015] In some schemes, the secondary star-shaped line dynamic pressure groove has a secondary dynamic pressure groove root and two secondary groove area side walls located on both sides of the secondary dynamic pressure groove root;

[0016] The secondary dynamic pressure groove root is in a circular arc shape, and the secondary groove area side walls extend along a star-shaped line.

[0017] In some schemes, the two secondary groove area side walls extend in the same direction or extend in opposite directions.

[0018] In some schemes, the parametric equation of the star-shaped line is:

[0019] wherein the constant a is the radial width of the secondary star-shaped line dynamic pressure groove, and the constant b is 2a-3a.

[0020] In some schemes, the groove depth of the primary star-shaped line dynamic pressure groove is 0.001mm-0.02mm; the groove depth of the secondary star-shaped line dynamic pressure groove is 0.001mm-0.02mm; and the groove depth of the pressure equalizing groove is 0.001mm-0.1mm.

[0021] The radial width of the primary sealing dam is 2mm-10mm, and the radial width of the secondary sealing dam is 1mm-5mm.

[0022] In some schemes, the cross-sectional shape of the back pressure drainage hole is square, circular or other shapes.

[0023] In some schemes, the number of the primary star-shaped line dynamic pressure grooves is 2-30, and the number of the secondary star-shaped line dynamic pressure grooves is 2-30.

[0024] The technical scheme provided by the present application can include the following beneficial effects:

[0025] 1. By setting the back pressure drainage hole in the pressure equalizing groove, the dry gas seal dynamic ring back pressure (inlet pressure) is introduced into the sealing dam area in the sealing gap, forming a pressure double inlet, realizing the inward movement of the high pressure area of the sealing end face, reducing the pressure drop area, and further improving the carrying capacity of the end face gas film.

[0026] 2. The secondary star-shaped line dynamic pressure groove-secondary sealing dam combination is set below the back pressure drainage hole to build a cascade dam area to further strengthen the flow resistance and pressure boosting effect of the sealing dam, and a secondary pressure peak can be formed at the near outlet position to improve the sealing opening capacity together with the back pressure drainage hole.

[0027] 3. By setting the primary star-shaped line dynamic pressure groove and the secondary star-shaped line dynamic pressure groove, the dynamic and static pressure is mixed in cascade, and during the mechanical start and stop process, the sealing back pressure is introduced through the back pressure drainage hole, which can improve the radial pressure distribution of the gas film, rapidly open or slowly close the sealing end face, avoid the generation of end face wear phenomenon, prolong the service life of the sealing element, and ensure the stable operation of the equipment.

[0028] 4. The star-shaped line dynamic pressure groove is used, and the bidirectional star-shaped line groove shape can be selected, and the star-shaped line dynamic pressure groove is symmetrically arranged on both sides, which can realize the clockwise and counterclockwise rotation sealing of the dry gas seal dynamic ring, and widen the application scene.

[0029] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0030] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures, and in which:

[0031] Figure 1 is a structural schematic view of the dry gas seal dynamic ring shown in embodiment one of the present application;

[0032] Figure 2 is another structural schematic view of the dry gas seal dynamic ring shown in embodiment one of the present application;

[0033] Figure 3 is a partial enlarged view of the dry gas seal dynamic ring shown in embodiment one of the present application;

[0034] Figure 4 is a dimensional schematic view of the dry gas seal dynamic ring shown in embodiment one of the present application;

[0035] Figure 5 is a structural schematic view of the back pressure drainage hole of the dry gas seal dynamic ring shown in embodiment one of the present application;

[0036] Figure 6 is a structural schematic view of the dry gas seal dynamic ring shown in embodiment two of the present application;

[0037] Figure 7 is a partial enlarged view of the dry gas seal dynamic ring shown in embodiment two of the present application;

[0038] Figure 8 is a structural schematic view of the dry gas seal dynamic ring shown in embodiment two of the present application;

[0039] Reference signs:

[0040] 1, main star-shaped dynamic pressure groove; 11, main dynamic pressure groove root; 12, main groove area side wall; 2, main dynamic pressure groove platform area; 3, secondary star-shaped dynamic pressure groove; 31, secondary dynamic pressure groove root; 32, secondary groove area side wall; 4, secondary seal dam; 5, secondary dynamic pressure groove platform area; 6, pressure equalizing groove; 7, main seal dam; 8, back pressure drainage hole;

[0041] R1 - dry gas seal dynamic ring outer diameter, R2 - main star-shaped dynamic pressure groove root radius, R3 - pressure equalizing groove outer diameter, R4 - pressure equalizing groove inner diameter, R5 - secondary star-shaped dynamic pressure groove root radius, R6 - dry gas seal dynamic ring inner diameter. DETAILED DESCRIPTION

[0042] The present application will be further described in conjunction with the drawings and specific embodiments, but the scope of protection of the present application is not limited to the content described.

[0043] Embodiment one:

[0044] As Figures 1 to 4 shown, the application provides a star-shaped line dynamic pressure groove-back pressure self-induction enhanced pressurized dry gas seal structure, comprising a dry gas seal moving ring; the outer diameter of the dry gas seal moving ring is the high-pressure inlet side, and the inner diameter is the low-pressure outlet side; the sealing end face of the dry gas seal moving ring is provided with a main star-shaped line dynamic pressure groove 1, which is uniformly spaced along the circumferential direction of the dry gas seal moving ring, so that a main dynamic pressure groove platform area 2 is formed between two adjacent main star-shaped line dynamic pressure grooves 1;

[0045] The main star-shaped line dynamic pressure groove 1 has a main dynamic pressure groove root 11 and two main groove area side walls 12 located on both sides of the main dynamic pressure groove root 11.

[0046] The main dynamic pressure groove root 11 is in the shape of a circular arc; the two main groove area side walls 12 extend along the star-shaped line.

[0047] The two main groove area side walls 12 are arranged in the same direction and curvedly extended.

[0048] The parametric equation of the star-shaped line is: Wherein, the parameter a is 7.78, and the parameter b is 15.56.

[0049] The inner side of the main star-shaped line dynamic pressure groove 1 is provided with a secondary star-shaped line dynamic pressure groove 3, which does not connect with the inner side of the dry gas seal moving ring, so that a secondary sealing dam 4 is formed between the inner side of the dry gas seal moving ring and the groove root of the secondary star-shaped line dynamic pressure groove 3; the secondary star-shaped line dynamic pressure groove 3 is uniformly spaced along the circumferential direction of the dry gas seal moving ring, so that a secondary dynamic pressure groove platform area 5 is formed between two adjacent secondary star-shaped line dynamic pressure grooves 3.

[0050] The secondary star-shaped line dynamic pressure groove 3 has a secondary dynamic pressure groove root 31 and two secondary groove area side walls 32 located on both sides of the secondary dynamic pressure groove root 31.

[0051] The secondary dynamic pressure groove root 31 is in the shape of a circular arc; the secondary groove area side wall 32 extends along the star-shaped line.

[0052] The two secondary groove area side walls 32 are arranged in the same direction and curvedly extended.

[0053] The parametric equation of the star-shaped line is: Wherein, the parameter a is 7.78, and the parameter b is 15.56.

[0054] The annular pressure equalizing groove 6 is provided between the main star-shaped line dynamic pressure groove 1 and the secondary star-shaped line dynamic pressure groove 3, which communicates with the secondary star-shaped line dynamic pressure groove and does not communicate with the main star-shaped line dynamic pressure groove 1, so that a main sealing dam 7 is formed between the pressure equalizing groove 6 and the groove root of the main star-shaped line dynamic pressure groove.

[0055] The back pressure drainage hole 8 is arranged through the dry gas seal dynamic ring and corresponds to the secondary star-shaped line dynamic pressure groove 3. In some embodiments, as shown in the figure, the back pressure drainage hole 8 can directly penetrate the dry gas seal dynamic ring backward, or can penetrate the dry gas seal dynamic ring from the outer side of the dry gas seal dynamic ring. Meanwhile, the end of the back pressure drainage hole 8 can be widened to improve the air intake. Figure 5

[0056] The cross-sectional shape of the back pressure drainage hole 8 is a slit.

[0057] The size R1 of the dry gas seal dynamic ring is 77.78 mm, and R6 is 58.42 mm; the groove root R2 of the main star-shaped line dynamic pressure groove 1 is 70 mm; the equalizing groove 6 is in the form of a ring belt, and the groove width (R3-R4) is 2 mm; the secondary star-shaped line dynamic pressure groove 3 starts from R4 which is 63 mm; the width (R5-R6) of the secondary seal dam 4 is 1.58 mm.

[0058] The groove depth of each main star-shaped line dynamic pressure groove 1 is 5 μm, and the parameters a and b are 7.78 and 15.56 respectively; the groove depth of the equalizing groove 6 is 5 μm, and the groove depth of each secondary star-shaped line dynamic pressure groove 3 is 5 μm, and the parameters a and b are 3 and 6 respectively. The main star-shaped line dynamic pressure groove 1 is provided with 12 grooves, and the groove ratio (R1-R2, the ratio of the area of the circular ring with grooves to the area without grooves) is 1; the secondary star-shaped line dynamic pressure groove 3 is provided with 24 grooves, and the groove ratio (R4-R5, the ratio of the area of the circular ring with grooves to the area without grooves) is 1.

[0059] The slit length-width ratio of the back pressure drainage hole 8 is 25, and the length is 1 mm.

[0060] The dry gas seal dynamic ring of the present example is compared with the classic spiral dynamic pressure groove dry gas seal dynamic ring which is the most widely used in current industrial applications. The traditional spiral dynamic pressure groove parameters are a spiral angle of 15°, a groove root radius of 70 mm, and a groove ratio of 1.

[0061] The working condition parameters are: external pressure Po=1 MPa, internal pressure Pi=0.1 MPa, dry gas seal dynamic ring back pressure Po=1 MPa, rotating speed w=1087.08 rad / s, working temperature T=25℃, and gas film thickness ho=5 μm. The numerical simulation results are shown in Table 1:

[0062] Table 1

[0063] Structure Opening force (N) Air film stiffness (10 8 N / m) Conventional spiral dynamic pressure groove 5599.84 11.1996 The present application 6764.76 13.5295

[0064] ​As can be seen from Table 1, the opening force of the dry gas seal dynamic ring of the embodiment is much greater than that of the traditional dry gas seal dynamic ring with spiral grooves, which can realize rapid opening or slow closing of the sealing end face, avoid the generation of end face wear phenomenon, prolong the service life of the sealing element, and the gas film stiffness is also greater than that of the traditional spiral dynamic pressure groove, which ensures the stable operation of the equipment.

[0065] Embodiment Two

[0066] As shown in Figure 6 and Figure 7 , based on embodiment one, the difference lies in that the two said secondary groove area side walls 32 are relatively curved and extended; the two said primary groove area side walls 12 are relatively curved and extended; the pressure equalizing groove 6 is fan-shaped and is arranged one by one corresponding to the secondary star-shaped line dynamic pressure groove 3; the back pressure drainage hole 8 is in the shape of a circular hole.

[0067] The size of the dry gas seal dynamic ring R1 is 48mm, and R6 is 36mm; the groove root R2 of the primary star-shaped line dynamic pressure groove 1 is 43mm; the groove width (R3-R4) of the pressure equalizing groove 6 is 1.5mm, and the fan angle is the same as that of the secondary star-shaped line dynamic pressure groove 3, which is 15°; the secondary star-shaped line dynamic pressure groove 3 starts from R4, which is 39.5mm; the width (R5-R6) of the secondary sealing dam 4 is 1mm.

[0068] Each of the primary and secondary star-shaped line dynamic pressure grooves 3 is symmetrically distributed, which can realize the rotation sealing of the dry gas seal dynamic ring in clockwise and counterclockwise directions. The groove depth of the primary star-shaped line dynamic pressure groove 1 is 5μm, and the parameters and are 5 and 15 respectively; the groove depth of the pressure equalizing groove 6 is 5μm, and the groove depth of each secondary star-shaped line dynamic pressure groove 3 is 5μm, and the parameters and are 2.5 and 7.5 respectively. The primary star-shaped line dynamic pressure groove 1 is provided with 8; the secondary star-shaped line dynamic pressure groove 3 is provided with 8. The outer diameter of the secondary star-shaped line dynamic pressure groove 3 corresponds to an angle of 15°.

[0069] The diameter of the circular hole of the back pressure drainage hole 8 is 0.3mm.

[0070] Embodiment Three

[0071] As shown in Figure 8 , based on embodiment one, the difference lies in that the difference lies in that:

[0072] The cross section of the back pressure drainage hole 8 is in the shape of a small hole, and the diameter thereof is 0.2mm. The primary star-shaped line dynamic pressure groove 1 is still a star-shaped line dynamic pressure groove, wherein the groove depth of each primary star-shaped line dynamic pressure groove 1 is 5μm, and the parameters and are 7.78 and 23.34 respectively; the groove depth of each secondary star-shaped line dynamic pressure groove 3 is 5μm, and the parameters and are 3 and 9 respectively. The groove table ratio is 0.5; the pressure equalizing groove 6 is an annular pressure equalizing groove 6, and the depth thereof is 10μm.

[0073] Having described various embodiments of the application, it is to be understood that the above description is meant not to limit and not to encompass all of the possible embodiments covered by the claims. Many modifications and variations of this application can be apparent to those of ordinary skill in the art without departing from the spirit and scope of the described embodiments. It is intended that the scope of the application should only be limited by the appended claims.

Claims

1. A star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas sealing structure, including a dry gas sealing dynamic ring, characterized by: The sealing end surface of the dry gas seal dynamic ring is provided with main star-shaped linear dynamic pressure grooves (1), and the main star-shaped linear dynamic pressure grooves (1) are evenly spaced along the circumferential direction of the dry gas seal dynamic ring, thereby forming an active pressure groove platform (2) between two adjacent main star-shaped linear dynamic pressure grooves (1); A secondary star-shaped linear dynamic pressure groove (3) is provided on the inner side of the primary star-shaped linear dynamic pressure groove (1), and the secondary star-shaped linear dynamic pressure groove (3) does not connect with the inner side surface of the dry gas sealing dynamic ring, thereby forming a secondary sealing dam (4) between the inner side surface of the dry gas sealing dynamic ring and the groove root of the secondary star-shaped linear dynamic pressure groove (3); the secondary star-shaped linear dynamic pressure grooves (3) are evenly spaced along the circumferential direction of the dry gas sealing dynamic ring, thereby forming a secondary dynamic pressure groove platform (5) between two adjacent secondary star-shaped linear dynamic pressure grooves (3); An annular pressure-equalizing groove (6) is provided between the primary star-shaped linear dynamic pressure groove (1) and the secondary star-shaped linear dynamic pressure groove (3); the pressure-equalizing groove (6) is in communication with the secondary star-shaped linear dynamic pressure groove (3) but is not in communication with the primary star-shaped linear dynamic pressure groove (1), thereby forming a main sealing dam (7) between the pressure-equalizing groove (6) and the groove root of the primary star-shaped linear dynamic pressure groove (1); A back pressure drainage hole (8) is provided in the pressure equalizing groove (6), and the back pressure drainage hole (8) is provided through the dry gas sealing dynamic ring and corresponds one to one with the secondary star-shaped linear dynamic pressure groove (3).

2. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 1, characterized in that: The main star-shaped linear dynamic pressure groove (1) comprises an active pressure groove root (11) and two main groove area side walls (12) located on both sides of the active pressure groove root (11); The active pressure groove root (11) is in an arc shape; the two main groove area side walls (12) extend along a star-shaped line.

3. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 2, characterized in that: The two main groove area side walls (12) are bent and extended in the same direction or are bent and extended relative to each other.

4. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 2, characterized in that: The parametric equation of the star line is: Wherein, the constant a is the radial width of the main star-shaped linear dynamic pressure groove (1), and the constant b is 2a-3a.

5. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 1, characterized in that: The secondary star-shaped linear dynamic pressure groove (3) comprises a secondary dynamic pressure groove root (31) and two secondary groove area side walls (32) located on both sides of the secondary dynamic pressure groove root (31); The secondary dynamic pressure groove root (31) is in an arc shape; the secondary groove area side wall (32) extends along a star-shaped line.

6. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 5, characterized in that: The two secondary groove area side walls (32) are bent and extended in the same direction or are bent and extended relative to each other.

7. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 5, characterized in that: The parametric equation of the star line is: Wherein, the constant a is the radial width of the secondary star-shaped linear dynamic pressure groove (3), and the constant b is 2a-3a.

8. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 1, characterized in that: The groove depth of the primary star-shaped linear dynamic pressure groove (1) is 0.001mm-0.02mm; the groove depth of the secondary star-shaped linear dynamic pressure groove (3) is 0.001mm-0.02mm; the groove depth of the equalizing pressure groove (6) is 0.001mm-0.1mm; The radial width of the primary sealing dam (7) is 2 mm to 10 mm; the radial width of the secondary sealing dam (4) is 1 mm to 5 mm.

9. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 1, characterized in that: The cross-sectional shape of the back pressure drainage hole (8) is square, circular or other shapes.

10. The star-shaped linear dynamic pressure groove-back pressure self-drainage enhanced pressurized dry gas seal structure according to claim 1, characterized in that: The number of the primary star-shaped linear dynamic pressure grooves (1) is 2-30; the number of the secondary star-shaped linear dynamic pressure grooves (3) is 2-30.

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