A diversion-type labyrinth seal structure with a lip shape

Abstract

The present invention provides a diversion type lip labyrinth seal structure for an oil pump, which includes an oil leakage collection device, a U-shaped diversion pipe, a stationary ring, a rotating ring, and a sealing panel. The sealing panel is fixed on the rotating ring; the U-shaped diversion pipe is arranged on the periphery of the sealing panel, one end is detachably fixed by an axial bracket and a radial bracket, the other end is fitted with the stationary ring, the upper end opening of the U-shaped diversion pipe is communicated with the oil leakage collection device through an oil pipe, a brush is arranged on the inner surface of the upper end pipe part, the upper end pipe part, the lower end part and the end face of the stationary ring enclose a first cavity, a first through hole is arranged at the bottom of the brush, and a second through hole is arranged on the wall of the lower end part; a plurality of first labyrinth tooth rings are arranged on one side of the stationary ring, and a second labyrinth tooth ring is arranged on the sealing panel; a first sealing ring and a second sealing ring are arranged in the U-shaped diversion pipe. The seal structure utilizes the triple seal throttling effects of brush seal, lip seal, and labyrinth seal, greatly improving the seal effect of the entire device, and at the same time being convenient for installation and beneficial to later maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of rotary shaft seals, and more specifically, to a diversion type lip labyrinth seal structure. Background Art

[0002] Labyrinth seals belong to non-contact seals, mainly utilizing the slit throttling effect, frictional effect, and cavity dissipation effect of their sealing gaps. Their sealing method is through the combined action of a series of sealing gaps and sealing cavities. The medium to be sealed passes through the sealing gaps and sealing cavities, and the pressure energy of the flowing fluid continuously decreases, greatly reducing the outlet flow rate and achieving the sealing effect.

[0003] The effectiveness of the seal determines the safety, reliability, and economy of mechanical equipment. Currently, high-performance and large-capacity rotating machinery is widely used, posing high requirements for the sealing performance of rotor machinery. Traditional rotary seals mainly include skeleton oil seals, labyrinth seals, and traditional mechanical seals. Skeleton oil seals have high cost performance in the short term, but have a high leakage rate during long-term operation. For long-term use of labyrinth seals, the oil leakage rate is still relatively large, and it is difficult to control environmental pollution. Traditional mechanical seals are time-consuming to install, require high installation accuracy, have high maintenance costs, and have a short service life. Therefore, there is a need to provide a rotary shaft seal structure with good sealing performance and easy maintenance. Summary of the Invention

[0004] In view of the deficiencies of existing rotary shaft seal devices, the present invention provides a diversion type lip labyrinth seal structure. On the premise of collecting and diverting leaked oil, it utilizes the triple sealing throttling effects of brush seals, lip seals, and labyrinth seals, overcomes the problem of leakage during long-term operation of traditional seals, collects the leaked oil in the seal structure described in the present invention, simultaneously prevents further leakage at the leakage points, avoids pollution of the equipment by the leaked oil, and improves the overall sealing performance.

[0005] The present invention adopts the following technical solutions:

[0006] A diversion type lip labyrinth seal structure for an oil pump, characterized by comprising a leaked oil collection device, a U-shaped diversion pipe, a stationary ring that can be fixed on the end cover, a rotating ring that can be fixed on the rotating shaft, and a sealing panel. The sealing panel is fixed on the rotating ring, and the sealing panel and the rotating ring rotate together with the rotating shaft;

[0007] Axial brackets and radial brackets are provided on the outer circumference of the sealing panel. The U-shaped diversion pipe is arranged outside the sealing panel, and one end is detachably fixed by the axial brackets and radial brackets, and the other end is fitted with the stationary ring. The U-shaped diversion pipe and the stationary ring do not rotate with the rotating shaft; and its upper end opening is communicated with the leaked oil collection device through an oil pipe;

[0008] A brush is provided on the inner surface of the inner side wall of the upper tube portion of the U-shaped diversion tube. A first cavity is formed among the end faces of the upper tube portion, the lower end portion of the U-shaped diversion tube and the static ring. A plurality of first labyrinth tooth rings are provided on the side of the static ring close to the sealing panel. A second labyrinth tooth ring staggered with the first labyrinth tooth ring is provided at the position corresponding to the static ring on the sealing panel. The first labyrinth tooth ring and the second labyrinth tooth ring form a labyrinth sealing structure;

[0009] A first sealing ring and a second sealing ring are respectively provided on the inner surface of the outer tube wall of the lower end portion of the U-shaped diversion tube and between the end portion of the static ring close to the end cover and the sealing panel. The first sealing ring, the second sealing ring and the sealing panel form a lip sealing structure, and the labyrinth sealing structure is located between the first sealing ring and the second sealing ring;

[0010] A first through hole communicating the upper tube portion of the U-shaped diversion tube with the first cavity is provided at the bottom of the brush. A second through hole is provided on the wall of the lower end portion of the U-shaped diversion tube for communicating the first cavity with the space between the first sealing ring and the labyrinth sealing structure.

[0011] Further, the first sealing ring and the second sealing ring are V-shaped sealing rings, which are composed of a pressing ring and a supporting ring. The inclination directions of the pressing rings of the two sealing rings are opposite, and they are in an "eight" shape structure with each other.

[0012] Further, the value range of the gap C between the lower end of the pressing ring of the first sealing ring and the second sealing ring and the sealing panel is 0.8-1.4 mm; the value range of the included angle θ between the pressing ring and the supporting ring is 20°-30°.

[0013] Further, an extension portion extending towards the inside of the first cavity is provided at the edge of the second through hole.

[0014] Further, the diameter of the second through hole is 2-3 mm, the number of the first through holes is multiple, and the diameter is 0.1-0.2 mm.

[0015] Further, a one-way valve is provided between the leakage oil collecting device and the U-shaped diversion tube.

[0016] Further, the static ring is of a split structure and is fixed into a ring shape by bolt connection; the static ring is positioned and fixed by a positioning step fixed on the end cover.

[0017] Further, the tops of the first labyrinth tooth ring and the second labyrinth tooth ring are both semi-elliptical. The length Sg of the tooth cavity is equal to the length 2b of the short axis of the ellipse; the tooth height a=(0.8-1.2)*2b, and the value range of the tooth top gap Hc is 4-6 mm; the sealing length is taken within 35 mm-45 mm, and the inlet length is equal to twice the outlet length, that is, S in =2S out .

[0018] Furthermore, the axial distance between the labyrinth seal mechanism and the second sealing ring is 3 - 5 mm.

[0019] Furthermore, the brush is an oil - repellent brush made of oil - repellent material, and the brushes are evenly distributed.

[0020] The diversion - type lip - type labyrinth seal structure provided by the present invention guides the fluid leaked from the oil pump into the seal device through the leakage oil collection device and the oil pipe, preventing the leakage oil from polluting the pump. In the seal structure of the present invention, the brush and the first through - hole at its bottom constitute the first - stage seal, the lip - seal structure formed between the first sealing ring, the second sealing ring and the seal panel is the second - stage seal of the present invention, and the labyrinth seal between the stationary ring and the seal panel is the third - stage seal.

[0021] The fluid enters the U - shaped diversion pipe through the oil inlet. At the brush, part of the fluid comes to the first sealing ring, and the other part of the fluid enters the first cavity through the first through - hole and stays in the first cavity. The liquid staying in the first cavity enters the gap between the first sealing ring and the labyrinth seal structure through the second through - hole; another part of the liquid located upstream of the first sealing ring passes through the sealing gap through the first sealing ring and all converges in front of the labyrinth seal structure. Through the throttling effect of the labyrinth seal, the remaining fluid flows into the second cavity after being throttled by the second sealing ring. On the one hand, the above - mentioned seal structure can collect the collected leakage oil, and on the other hand, it also uses the three - stage seal structure to provide resistance to the leakage oil flowing into the collection space, providing a certain pressure resistance to the leakage point, slowing down and reducing the leakage amount.

[0022] In the U - shaped diversion pipe, the collected leakage oil preferentially enters the first cavity through the first through - hole at the bottom of the brush. As the fluid in the first cavity increases, the pressing force on the first sealing lip becomes greater. Therefore, the sealing performance of the first sealing lip can be enhanced. At the same time, due to the gap between the first cavity and the labyrinth seal, the contact stress between the first sealing lip and the seal panel will not be too large, and the generated friction force will not be too large, which is beneficial to improving the sealing effect and extending the service life of the seal. Therefore, the lip - type seal structure can be well self - adjusted and can also play a good sealing role.

[0023] The first cavity in the present invention plays a role in diverting and throttling the incoming flow. Part of the fluid enters the first cavity, and part of the fluid flows along the pipeline to the first sealing ring, reducing the pressure of the fluid on the first sealing ring, avoiding serious wear of the compression ring and the sealing ring of the sealing ring due to excessive pressure, and even reverse flow phenomenon, which is beneficial to extending the service life of the device. Most of the fluid entering the first cavity stays in the cavity, sharing the pressure of the second cavity and extending the one - time use duration of the device.

[0024] The sealing ring used in the present invention is a V-shaped sealing ring, which is composed of a pressure ring and a support ring, has high pressure resistance and long service life. The pressure rings of the two sealing rings are inclined in opposite directions and are in an "eight" shape with each other. As the flow rate increases, the pressure generated by the fluid on the pressure ring of the first sealing ring also increases. The pressure causes the gap between the pressure ring of the first sealing ring and the lower wall to gradually decrease, and the sealing effect is further improved. At the same time, the sealing ring not only plays a throttling role on the incoming flow, but also can hinder the backflow of the fluid in the U-shaped guide tube and the second cavity, greatly improving the sealing effect of the entire device. In addition, since there is a gap between the sealing ring pressure ring and the sealing panel, the contact stress between the sealing ring and the sealing panel will not be too large, and the friction generated will not be too large, which is conducive to extending the life of the sealing device.

[0025] The brush is an oleophobic brush, and the through holes at the bottom are arranged at equal intervals, which is conducive to the fluid from the oil inlet to enter the first cavity. The brush is oleophobic and can return to its original state after the oil inlet stops, and the inherent gaps are still maintained between each other.

[0026] The two sets of semi-elliptical labyrinth tooth rings of the labyrinth seal are staggered in the U-shaped guide tube, which is beneficial to enhance the friction effect and the flow contraction effect. The pressure of the fluid flowing through can be reduced, and the outlet flow rate is greatly reduced, which plays a positive role in improving the sealing performance.

[0027] In the present invention, one side of the bottom of the U-shaped guide tube is fixedly connected to the sealing panel by an axial bracket and a radial bracket, which is not only easy to install, but also only needs to open the bracket during later maintenance to clean and maintain the lower pipeline of the entire U-shaped guide tube, effectively reducing the maintenance cost while taking into account the requirements for rotor stability, which has important engineering significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the flow-guiding lip-shaped labyrinth seal structure described in the present invention.

[0029] Figure 2 Schematic diagram of brush seal structure.

[0030] Figure 3 The figure is a schematic diagram of the sealing ring structure of the present invention.

[0031] Figure 4 This is a schematic diagram of the size ratio of the labyrinth seal structure described in the present invention.

[0032] Figure 5 The leakage simulation data before and after the installation of the guide lip labyrinth seal structure described in the present invention.

[0033] The following are the descriptions of the reference numerals:

[0034] 1 - Rotating shaft; 2 - Sealing panel; 3 - Check valve; 4 - U-shaped diversion pipe; 5 - Brush; 6 - First cavity; 7 - First sealing ring; 8 - Stationary ring; 9 - Rotating ring; 10 - Second cavity; 11 - Positioning step; 12 - Second sealing ring; 13 - Axial support; 14 - Radial support; 15 - End cover; 16 - Support ring; 17 - Pressure ring; 18 - Oil pipe; 19 - First labyrinth tooth ring; 20 - Second labyrinth tooth ring. Detailed implementation manners

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0036] The diversion type lip labyrinth seal structure described in the present invention is installed between the rotating shaft and the end cover, as Figure 1 shown, and includes a leakage oil collection device, a U-shaped diversion pipe 4, a stationary ring 8 that can be fixed on the end cover 15, a rotating ring 9 that can be fixed on the rotating shaft 1, and a sealing panel 2. The sealing panel 2 is fixed on the rotating ring 9, and the sealing panel 2 and the rotating ring 9 rotate together with the rotating shaft 1. For the convenience of installation and disassembly, the stationary ring 8 is set as a split structure and is fixed into a ring shape by bolt connection; the stationary ring 8 is positioned and fixed by the positioning step 11 fixed on the end cover 15.

[0037] Axial supports 13 and radial supports 14 are arranged on the outer circumference of the sealing panel 2. The U-shaped diversion pipe 4 is arranged outside the sealing panel 2, and one end is detachably fixed by the axial support 13 and the radial support 14, and the other end is matched with the stationary ring 8. The U-shaped diversion pipe 4 and the stationary ring 8 do not rotate with the rotating shaft 1. And its upper end opening is communicated with the leakage oil collection device through an oil pipe 18. A check valve 3 is arranged between the leakage oil collection device and the U-shaped diversion pipe 4 to prevent the collected leakage oil from flowing back to the leakage site. In this embodiment, both the axial support 13 and the radial support 14 are connected to the rotating ring by threads.

[0038] A brush 5 is arranged on the inner surface of the inner side wall of the upper end pipe part of the U-shaped diversion pipe 4. A first cavity 6 is formed among the upper end pipe part, the lower end part of the U-shaped diversion pipe 4 and the end face of the stationary ring 8. A plurality of first labyrinth tooth rings 19 are arranged on the side of the stationary ring 8 close to the sealing panel 2, and second labyrinth tooth rings 20 staggered with the first labyrinth tooth rings 19 are arranged at the corresponding positions of the sealing panel 2 and the stationary ring 8. The first labyrinth tooth rings 19 and the second labyrinth tooth rings 20 form a labyrinth seal structure.

[0039] As Figure 4As shown, the tops of the first labyrinth tooth ring 19 and the second labyrinth tooth ring 20 are both semi-elliptical, the length Sg of the tooth cavity is equal to the length 2b of the minor axis of the ellipse; the tooth height a = (0.8 - 1.2) * 2b, and the value range of the tooth tip clearance Hc is 4 - 6 mm; the sealing length is taken within 35 mm - 45 mm, and the inlet length is equal to twice the outlet length, i.e., S in = 2S out .

[0040] A first sealing ring 7 and a second sealing ring 12 are respectively arranged on the inner surface of the outer wall of the lower end of the U-shaped diversion pipe 4 and between the end of the stationary ring 8 close to the end cover 15 and the sealing panel 2. The first sealing ring 7, the second sealing ring 12 and the sealing panel 2 form a lip seal structure, and the labyrinth seal structure is located between the first sealing ring 7 and the second sealing ring 12. The space between the labyrinth seal structure and the second sealing ring 12 is the second cavity 10, and the length of the second cavity 10 in the axial direction of the rotating shaft 1 is 3 - 5 mm.

[0041] As Figure 3 shown, the first sealing ring 7 and the second sealing ring 12 are V-shaped sealing rings, which are composed of a pressing ring 17 and a supporting ring 16. The inclination directions of the pressing rings 17 of the two sealing rings are opposite, and they are in a "V" - shaped structure with each other. The value range of the gap C between the lower ends of the pressing rings 17 of the first sealing ring 7 and the second sealing ring 12 and the sealing panel 2 is 0.8 - 1.4 mm; the value range of the angle θ between the pressing ring 17 and the supporting ring 16 is 20° - 30°

[0042] As Figure 2 shown, a first through - hole communicating the upper pipe part of the U-shaped diversion pipe 4 and the first cavity 6 is arranged at the bottom of the brush 5. The brush 5 can be an oil - repellent brush made of an oil - repellent material. The number of the first through - holes is multiple and they are evenly distributed among the brushes 5. The diameter of the first through - hole is 0.1 - 0.2 mm.

[0043] A second through - hole is arranged on the wall of the lower end of the U-shaped diversion pipe 4 for communicating the first cavity 6 and the space between the first sealing ring 7 and the labyrinth seal structure. An extension part extending towards the inside of the first cavity 6 is arranged at the edge of the second through - hole to slow down the transfer of the liquid staying in the first cavity 6 to the labyrinth seal.

[0044] The provided diversion lip-shaped labyrinth seal structure of the present invention guides the fluid leaked from the oil pump through the oil leakage collection device and the oil pipe 18 into the U-shaped diversion pipe 4 through the oil inlet. At the brush, a part of the fluid reaches the first sealing ring 7, and another part of the fluid enters the first cavity 6 through the first through hole and stays in the first cavity 6. The liquid staying in the first cavity 6 enters the gap between the first sealing ring 7 and the labyrinth seal structure through the second through hole; another part of the liquid located upstream of the first sealing ring 7 passes through the first sealing ring 7 through the sealing gap and all converges in front of the labyrinth seal structure. Through the throttling effect of the labyrinth seal, the remaining fluid flows into the second cavity after being throttled by the second sealing ring 12. On the one hand, the above-mentioned seal structure can collect the collected leaked oil, and on the other hand, it also uses the three seal structures to provide resistance to the leaked oil flowing into the collection space, providing a certain pressure resistance to the leakage point, slowing down and reducing the leakage amount.

[0045] In a specific case, the rotor diameter is 30 mm. According to the aforementioned seal structure, parameters such as the rotor diameter D, the total seal length L, the tooth cavity length Sg, and the number of teeth N are determined, and the specific numerical values of the determined parameters are shown in Table 1.

[0046] Table 1. Design parameters of the labyrinth tooth ring

[0047] Number of teeth N (pcs) 8 Total sealing length L (mm) 40 Semi-major axis of ellipse a (mm) 4 Minor axis of ellipse 2b (mm) 4 Tooth cavity length Sg (mm) 4 Tooth tip clearance Hc (mm) 5 Rotor diameter D (mm) 30

[0048] To further study the leakage characteristics of the seal structure described in the present invention, the actual leakage amount Q1 under different pressure differences is calculated through numerical simulation, and compared with the leakage amount Q2 in the case without this seal structure, as Figure 5 shown. Thus, the reduction rate δ of the leakage amount is calculated. Among them,

[0049]

[0050] As can be seen from the figure, the reduction rate of the leakage amount remains at about 70%, so it can be obtained that the diversion lip-shaped labyrinth seal structure has good sealing performance.

[0051] The described embodiments are the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Without departing from the essential content of the present invention, any obvious improvements, substitutions or modifications that those skilled in the art can make all belong to the protection scope of the present invention.

Claims

1. A diversion lip-type labyrinth seal structure for an oil pump, characterized in that, It includes an oil leakage collection device, a U-shaped diversion pipe (4), a stationary ring (8) that can be fixed on the end cover (15), a moving ring (9) that can be fixed on the rotating shaft (1), and a sealing panel (2). The sealing panel (2) is fixed on the moving ring (9), and the sealing panel (2) and the moving ring (9) rotate together with the rotating shaft (1). An axial support (13) and a radial support (14) are arranged on the outer circumference of the sealing panel (2). The U-shaped diversion pipe (4) is arranged outside the sealing panel (2), and one end is detachably fixed by the axial support (13) and the radial support (14), and the other end is matched with the stationary ring (8). The U-shaped diversion pipe (4) and the stationary ring (8) do not rotate with the rotating shaft (1); and its upper end opening is communicated with the oil leakage collection device through an oil pipe. A brush (5) is arranged on the inner surface of the inner side wall of the upper end pipe part of the U-shaped diversion pipe (4). A first cavity (6) is formed between the upper end pipe part, the lower end part of the U-shaped diversion pipe (4) and the end face of the stationary ring (8). A plurality of first labyrinth tooth rings (19) are arranged on the side of the stationary ring (8) close to the sealing panel (2). A second labyrinth tooth ring (20) that intersects with the first labyrinth tooth ring (19) is arranged at the corresponding position of the sealing panel (2) and the stationary ring (8). The first labyrinth tooth ring (19) and the second labyrinth tooth ring (20) form a labyrinth sealing structure. A first sealing ring (7) and a second sealing ring (12) are respectively arranged on the inner surface of the outer side wall of the lower end part of the U-shaped diversion pipe (4), between the end of the stationary ring (8) close to the end cover (15) and the sealing panel (2). A lip sealing structure is formed between the first sealing ring (7), the second sealing ring (12) and the sealing panel (2), and the labyrinth sealing structure is located between the first sealing ring (7) and the second sealing ring (12). A first through hole communicating the upper end pipe part of the U-shaped diversion pipe (4) and the first cavity (6) is arranged at the bottom of the brush (5). A second through hole is arranged on the wall of the lower end part of the U-shaped diversion pipe (4) for communicating the first cavity (6) with the space between the first sealing ring (7) and the labyrinth sealing structure.

2. The flow - guiding lip - type labyrinth seal structure for an oil pump according to claim 1, wherein The first sealing ring (7) and the second sealing ring (12) are V-shaped sealing rings, which are composed of a pressing ring (17) and a support ring (16). The inclination directions of the pressing rings (17) of the two sealing rings are opposite, and they are in an "eight" - shaped structure with each other.

3. The flow guiding lip-shaped labyrinth seal structure for an oil pump according to claim 2, wherein, The value range of the gap C between the lower ends of the pressing rings (17) of the first sealing ring (7) and the second sealing ring (12) and the sealing panel (2) is 0.8 - 1.4 mm; the value range of the included angle θ between the pressing ring (17) and the support ring (16) is 20° - 30°.

4. The flow guiding lip-shaped labyrinth seal structure for an oil pump according to claim 1, wherein, An extension part extending towards the inside of the first cavity (6) is arranged at the edge of the second through hole.

5. The flow-guided labyrinth seal structure for an oil pump according to claim 4, characterized in that, The diameter of the second through hole is 2 - 3 mm. The number of the first through holes is multiple and they are evenly distributed among the brushes (5). The diameter of the first through hole is 0.1 - 0.2 mm.

6. The flow - guiding lip - type labyrinth seal structure for an oil pump according to claim 1, characterized in that, A one - way valve (3) is arranged between the oil leakage collection device and the U-shaped diversion pipe (4).

7. The flow-guided labyrinth seal structure for an oil pump according to claim 1, wherein, The stationary ring (8) has a split structure and is fixed into a ring shape by bolt connection; the stationary ring (8) is positioned and fixed by a positioning step (11) fixed on the end cover (15).

8. The flow - guiding lip - type labyrinth seal structure for an oil pump according to claim 1, characterized in that, The tops of the first labyrinth tooth ring (19) and the second labyrinth tooth ring (20) are both semi-elliptical. The length Sg of the tooth cavity is equal to the length 2b of the minor axis of the ellipse; the tooth height a = (0.8 - 1.2) * 2b, and the value range of the tooth tip clearance Hc is 4 - 6 mm; the sealing length is taken within 35 mm to 45 mm, and the inlet length is equal to twice the outlet length, i.e., S in = 2S out .

9. The flow-guided labyrinth seal structure for an oil pump according to claim 1, characterized in that, The axial distance between the labyrinth seal structure and the second sealing ring (12) is 3 - 5 mm.

10. The flow-guided lip labyrinth seal structure for an oil pump according to claim 1, characterized in that, The brush (5) is an oil-repellent brush made of oil-repellent material.

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