Sealing device

Abstract

Provided is a sealing device with simple pressure control. A sealing device (1) is provided with: a cylindrical body (10) into which a rotating shaft (2) is inserted; a sealing device (1) for sealing a rotating shaft (2) and a cylindrical body (10), the sealing device (1) having at least two sealing spaces (S5, S6) interposed between the sealing ring (25) and the cylindrical body (10), in which a sealing fluid (OL3) is introduced from the outside into one of the sealing spaces (S5), the one of the sealing spaces (S5) and the other of the sealing spaces (S6) being communicated through a flow path (6), and the sealing fluid (OL3) being introduced from the outside into the other of the sealing spaces (S5, S6) through the flow path (6), the sealing fluid (OL3) being introduced into the other of the sealing spaces (S5, S6) being introduced into the other of the sealing spaces (S5, S6) through the flow path (6). The flow path (6) is provided with a pressure adjustment device (30) that adjusts the pressure of the sealing fluid (OL3) introduced into one of the sealed spaces (S5) and introduces the sealing fluid (OL3) into the other sealed space (S6).

Description

Technical Field

[0001] This invention relates to sealing devices, and more particularly to sealing devices for sealing relatively rotating parts of rotating machinery applicable to ship propellers or tidal current generators. Background Technology

[0002] In the sealing devices of rotating machinery such as propellers or tidal generators installed on ships, sometimes the sealed fluid inside the machine, such as lubricating oil, is prevented from leaking to the outside of the ship and external fluids such as seawater are prevented from entering the machine by sealing the annular gap formed in the relatively rotating parts.

[0003] For example, the sealing device in Patent Document 1 is located at both axial ends of the stern tube supporting the bearings of the propeller shaft, and uses the sealing devices on both sides to seal lubricating oil into the stern tube. The sealing device has a cylindrical component and a first to a third sealing ring, which are axially separated and mounted on the inner circumferential surface of the cylindrical component. Each sealing ring is a lip seal, and its inner diameter end slides on the outer circumferential surface of a sleeve that is externally fixed to the propeller shaft.

[0004] A first space is defined between the first and second sealing rings on the outer side of the ship. A fluid with a pressure higher than seawater pressure is supplied to the first space from an external first supply device. A second space is defined between the second and third sealing rings on the inner side of the ship. A fluid with a pressure higher than the fluid pressure in the first space and the hydraulic pressure in the stern tube is supplied to the second space from an external second supply device.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2018 / 216155 (page 7) Figure 2 ) Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In a sealing device like that in Patent Document 1, the lip of the second sealing ring is pressed against the sleeve by the fluid pressure in the second space, which is higher than the fluid pressure in the first space, thus sealing the first space and the second space and preventing lubricating oil from leaking to the outside of the machine.

[0010] However, in the sealing device like that in Patent Document 1, fluid with pressure adjusted by the first supply device is supplied to the first space, and fluid with pressure adjusted by the second supply device is supplied to the second space. Therefore, if the seawater pressure changes, the pressure of each fluid needs to be adjusted separately, making the pressure control of the first space and the second space complicated.

[0011] This invention was made in view of such a problem, and its purpose is to provide a sealing device with simple pressure control.

[0012] Methods for solving problems

[0013] To address the aforementioned issues, the sealing device of the present invention comprises: a cylindrical body through which a rotating shaft is inserted; and a sealing ring installed on the cylindrical body to seal between the cylindrical body and the rotating shaft. The sealing device has at least two sealing spaces separated by the sealing ring, wherein a sealing fluid is introduced from the outside into one of the sealing spaces, and the one sealing space is connected to the other sealing space via a flow path. A pressure adjusting device is provided in the flow path to adjust the pressure of the sealing fluid introduced into the one sealing space and introduce it into the other sealing space.

[0014] Therefore, the pressure of the adjusted sealing fluid introduced into one sealing space can be adjusted by using a pressure adjusting device and introduced into the other sealing space, thus making it easy to adjust the sealing space of one sealing space and the other sealing space to an appropriate pressure.

[0015] Alternatively, the flow path may be formed in the cylindrical body.

[0016] Therefore, there is no need to configure piping or other components on the outside of the cylindrical body to connect to another sealed space, thus enabling the sealing device to be constructed in a compact manner.

[0017] Alternatively, the sealing space of the other party may be located closer to the inside of the machine than the sealing space of the first party, and an oil chamber may be located even closer to the inside of the machine in the sealing space of the other party.

[0018] Therefore, oil that wants to leak from the oil chamber inside the machine to the outside can be recovered in the sealed space of the low-pressure side, and oil leakage to the outside of the machine can be prevented because a sealed space of the high-pressure side is provided on the outside of the sealed space of the other side.

[0019] Alternatively, the sealing space of one party may be adjacent to the sealing space of the other party, and the sealing ring may be a lip seal, thereby increasing the sealing force of the sealing ring by utilizing the pressure difference between the sealing spaces of the two parties.

[0020] Therefore, by utilizing the pressure difference between the sealing spaces of one and the other, the sealing force of the lip seal is increased, thus effectively preventing fluid leakage. Furthermore, fluid does not easily move between the sealing spaces of one and the other from outside the flow path, making it easy to adjust the pressure in both sealing spaces.

[0021] Alternatively, the fluid within the sealed space of the other party can be discharged to the outside.

[0022] This allows fluid to be discharged from the sealed space of the other party to the outside.

[0023] The pressure regulating device is a valve in which the valve core is stressed by a spring.

[0024] Therefore, the opening can be adjusted according to the pressure difference between the sealing spaces of one side and the other side. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view showing the sealing device of Embodiment 1 of the present invention.

[0026] Figure 2 This is an exploded view showing the construction of a pressure regulating valve.

[0027] Figure 3 It is a schematic diagram showing the pressure status of each sealed space.

[0028] Figure 4 This is a cross-sectional view showing the sealing device of Embodiment 2 of the present invention.

[0029] Figure 5 This is a cross-sectional view showing the sealing device of Embodiment 3 of the present invention. Detailed Implementation

[0030] Hereinafter, the sealing device for implementing the present invention will be described based on embodiments.

[0031] Example 1

[0032] Reference Figures 1-3 The sealing device of Example 1 will be described. Furthermore, in this example, a sealing device used in the stern tube of a ship will be used as an example. And, Figure 1 The left side of the paper is designated as the stern side (outer side of the ship). Figure 1 The right side of the paper is described as the bow side (inner side of the ship), the stern side (outer side of the ship) is the outer side of the sealing device, and the bow side (inner side of the ship) is the inner side of the sealing device.

[0033] like Figure 1 As shown, the sealing device 1 of the present invention is a shaft sealing device for a ship's propeller. Inside the stern tube 100 through which the propeller shaft 2, which serves as the rotation axis of the propeller 3, is inserted, a bearing (not shown) is disposed and sealed with lubricating oil OL1, which is the fluid to be sealed.

[0034] A sealing device 1 is provided on the stern side of the stern tube 100. This sealing device 1 is used to prevent lubricating oil OL1, which is an internal fluid, from leaking out of the ship from between the stern tube 100 and the sleeve 4, which is externally fixed to the propeller shaft 2, and to prevent seawater SW1, which is an external fluid, from entering the ship. In this embodiment, the sleeve 4 forms part of the propeller shaft 2.

[0035] In addition, a sealing device (not shown) is provided on the bow side of the stern pipe 100 to prevent lubricating oil from leaking from between the stern pipe 100 and the propeller shaft 2 into the ship's engine room.

[0036] like Figure 1 As shown, the sealing device 1 mainly consists of a housing 10 as a cylindrical body, a first lip seal 21 to a sixth lip seal 26, and a pressure reducing valve 30 as a pressure adjusting device.

[0037] The hull 10 is formed into a generally cylindrical shape by integrally connecting the first segmented hull 10a, the second segmented hull 10b, the third segmented hull 10c, the fourth segmented hull 10d, the fifth segmented hull 10e, the sixth segmented hull 10f, and the seventh segmented hull 10g, which are sequentially interlocked along the axial direction, using bolts or the like (not shown). In the hull 10, the flange of the seventh segmented hull 10g, formed on the bow side, is fixed to the stern tube 100 by bolts or the like (not shown).

[0038] The outer diameter portion of the first lip seal 21 is sealed between the first segmented housing 10a and the second segmented housing 10b. The outer diameter portion of the second lip seal 22 is sealed between the second segmented housing 10b and the third segmented housing 10c. The outer diameter portion of the third lip seal 23 is sealed between the third segmented housing 10c and the fourth segmented housing 10d.

[0039] The outer diameter portion of the fourth lip seal 24 is sealed between the fourth segmented housing 10d and the fifth segmented housing 10e. The outer diameter portion of the fifth lip seal 25 is sealed between the fifth segmented housing 10e and the sixth segmented housing 10f. The outer diameter portion of the sixth lip seal 26 is sealed between the sixth segmented housing 10f and the seventh segmented housing 10g.

[0040] Furthermore, a seal 5 is installed on the inner circumferential surface of the first segment housing 10a to prevent foreign objects from entering.

[0041] Between the housing 10 and the sleeve 4, multiple sealing spaces are divided axially by the first lip seal 21 to the sixth lip seal 26.

[0042] Specifically, a first sealing space S1 is formed between the seal 5 and the first lip seal 21. A second sealing space S2 is formed between the first lip seal 21 and the second lip seal 22. A third sealing space S3 is formed between the second lip seal 22 and the third lip seal 23. A fourth sealing space S4 is formed between the third lip seal 23 and the fourth lip seal 24.

[0043] A fifth sealing space S5, serving as one sealing space, is formed between the fourth lip seal 24 and the fifth lip seal 25. A sixth sealing space S6, serving as the other sealing space, is formed between the fifth lip seal 25 and the sixth lip seal 26. Furthermore, an oil chamber S7, the inner side of the stern tube 100, is formed on the inner side of the sixth sealing space S6.

[0044] The first lip seal 21 is configured with its lip 21a facing outwards from the ship. The pressure inside the first lip seal 21, i.e., the pressure within the first sealing space S1, functions as part of the tightening pressure applied to the lip 21a. Furthermore, the second lip seal 22, the fourth lip seal 24, the fifth lip seal 25, and the sixth lip seal 26 have substantially the same structure as the first lip seal 21.

[0045] Furthermore, the third lip seal 23 is configured such that the lip 23a faces the inside of the ship, and the pressure on the inside of the third lip seal 23, i.e. the pressure in the fourth sealing space S4, functions as part of the tightening pressure on the lip 23a.

[0046] A second sealed space S2 is formed in the second segmented housing 10b.

[0047] The third segment housing 10c has a communication hole 13 that connects the third sealed space S3 to the external air inlet device 41, and an outlet hole (not shown) that connects the third sealed space S3 to the external outlet container 42.

[0048] A connecting hole 14 is formed in the fourth segment housing 10d to connect the fourth sealing space S4 with the first oil supply device 43.

[0049] The fifth segment housing 10e has a communication hole (not shown) that connects the fifth sealing space S5 to the second oil supply device 44, and a communication hole 61 that forms part of the flow path 6 that connects the fifth sealing space S5 to the sixth sealing space S6.

[0050] The connecting hole 61 is generally T-shaped, having a radially penetrating portion and a branch portion extending inward from the middle of this portion towards the inner side of the ship. A pressure reducing valve 30, described later, is installed on the outer diameter side of the radially penetrating portion of the connecting hole 61.

[0051] Furthermore, a connecting hole 62 is formed in the sixth segment housing 10f to connect the fifth sealing space S5 and the sixth sealing space S6. The connecting hole 62, together with the connecting hole 61, forms part of the flow path 6. The connecting hole 62 extends in an inverted L-shape from the branch portion of the connecting hole 61 and communicates with the sixth sealing space S6.

[0052] The flow path 6 of the present invention is composed of a connecting hole 61 and a connecting hole 62, which connects the fifth sealing space S5 and the sixth sealing space S6.

[0053] Furthermore, a discharge port (not shown) is formed in the sixth segment housing 10f, which communicates with the sixth sealed space S6 and the external discharge container 45.

[0054] In addition, this embodiment illustrates a configuration with discharge container 42 and discharge container 45 respectively, but the same discharge container can also be used.

[0055] like Figure 1 and Figure 2 As shown, the pressure reducing valve 30 is a lift valve, mainly composed of a fixed plunger 31, a pressure adjusting rod 32, a push plate 33, a spring 34, a valve core 35, a valve seat component 36, and a cover 37.

[0056] The fixed plunger 31 is screwed to the outer diameter side of the radially penetrating portion of the communicating hole 61 of the fifth segment housing 10e via a gasket 30a.

[0057] The pressure adjusting rod 32 is screwed and fixed to the fixed plunger 31 in a position that can be adjusted. A fixing nut 30c is screwed onto the portion of the pressure adjusting rod 32 that extends outward from the fixed plunger 31 via a spring washer 30b to prevent the screwed state between the pressure adjusting rod 32 and the fixed plunger 31 from loosening due to vibration or other reasons.

[0058] On the outside of the fixed plunger 31, a cover 37 is externally fixed via a gasket 30d.

[0059] On the inner diameter side of the pressure adjusting rod 32 of the fixed plunger 31, a valve core 35 is arranged via a push plate 33 and a spring 34 in a manner that allows it to contact and separate from the valve seat component 36.

[0060] A valve seat component 36 is screwed onto the inner diameter side of the radially penetrating portion of the connecting hole 61 in the fifth segment housing 10e. This valve seat component 36 has a valve seat, and the opening degree of the flow path 6 can be adjusted by the valve core 35 contacting and separating from the valve seat.

[0061] Furthermore, the force of the spring 34 that applies force to the valve core 35 on the valve seat component 36 side can be adjusted by adjusting the relative position of the pressure adjusting rod 32 relative to the fixed plunger 31.

[0062] Next, the fluid pressure in each sealed space will be explained.

[0063] like Figure 3 As shown, seawater SW1 flows into the first sealed space S1 through the gap between the seal 5 and the sleeve 4. The first sealed space S1 and the external space S8 are at approximately the same pressure.

[0064] Air A in the third sealed space S3 (described later) is ejected from between the second lip seal 22 and the sleeve 4 and introduced into the second sealed space S2. Furthermore, the air introduced into the second sealed space S2 is ejected from between the first lip seal 21 and the sleeve 4 toward the first sealed space. The pressure in the second sealed space S2 is adjusted to be higher than the seawater pressure and lower than the pressure in the fourth sealed space S4.

[0065] Air A at a pressure lower than that in the second sealed space S2 and the fourth sealed space S4 is continuously introduced into the third sealed space S3 from the air inlet device 41. The air inlet device 41 uses a pressure sensor (not shown) to detect the pressure in the second sealed space S2 and the fourth sealed space S4, and adjusts the pressure of air A to be lower than the detected pressure in the second sealed space S2 and the fourth sealed space S4.

[0066] Therefore, the pressure in the third sealing space S3 is lower than the pressure in the second sealing space S2, which serves as the tightening pressure of the lip 22a of the second lip seal 22, thus improving the sealing force of the second lip seal 22. Similarly, the pressure in the third sealing space S3 is lower than the pressure in the fourth sealing space S4, which serves as the tightening pressure of the lip 23a of the third lip seal 23, thus improving the sealing force of the third lip seal 23.

[0067] Furthermore, the third sealed space S3 is connected to the discharge container 42, so even if seawater SW2 in the second sealed space S2 and / or lubricating oil OL2 in the fourth sealed space S4 flow into the third sealed space S3, it can be recovered to the external discharge container 42. In addition, an on / off valve is formed in the flow path between the third sealed space S3 and the discharge container 42, which can appropriately change the connection state.

[0068] Lubricating oil OL2, which is at a pressure slightly higher than that of oil chamber S7, is continuously introduced from the first oil supply device 43 into the fourth sealed space S4.

[0069] Lubricating oil OL3, which has a lower pressure than that in the fourth sealing space S4, is always introduced into the fifth sealing space S5 from the second oil supply device 44. The pressure in the fifth sealing space S5 is adjusted by the flow throttling of the pressure reducing valve 30, and is lower than the pressure in the fourth sealing space S4.

[0070] Therefore, the pressure in the fifth sealing space S5 is lower than the pressure in the fourth sealing space S4, which is the tightening pressure of the lip 24a of the fourth lip seal 24, thus improving the sealing force of the fourth lip seal 24.

[0071] The pressure in the fifth sealing space S5 pushes the valve core 35 of the pressure reducing valve 30 upward, and the lubricating oil OL3 in the fifth sealing space S5 flows into the sixth sealing space S6 through the part of the flow path 6 that is throttled by the pressure reducing valve 30.

[0072] That is, due to the pressure loss when passing through the pressure reducing valve 30, the lubricating oil OL4, which is depressurized, flows into the sixth sealing space S6, so the pressure in the sixth sealing space S6 becomes lower than the pressure in the fifth sealing space S5.

[0073] Therefore, the pressure in the sixth sealing space S6 is lower than the pressure in the fifth sealing space S5, which is the tightening pressure of the lip 25a of the fifth lip seal 25, thus improving the sealing force of the fifth lip seal 25.

[0074] Furthermore, the pressure in the sixth sealed space S6 is lower than the pressure in the oil chamber S7. Therefore, although the lubricating oil OL1 in the oil chamber S7 may sometimes enter the sixth sealed space S6, the lubricating oil OL1 that has entered the sixth sealed space S6 can be discharged to the discharge container 45. In addition, an on / off valve is provided in the flow path between the sixth sealed space S6 and the discharge container 45 to appropriately change the connection state.

[0075] As explained above, the pressure-reducing valve 30 can be used to adjust the pressure of the lubricating oil OL3, which is adjusted by the second oil supply device 44, introduced into the fifth sealing space S5 and then introduced into the sixth sealing space S6. Therefore, the fifth sealing space S5 and the sixth sealing space S6 can be easily adjusted to appropriate pressures. Moreover, there is no need to install a separate oil supply device different from the second oil supply device 44, thus enabling a compact structure.

[0076] Furthermore, the flow path 6 is located within the housing 10. As a result, there is no need to install piping and pressure reducing valve 30 connecting the fifth sealing space S5 and the sixth sealing space S6 outside the housing 10, thus enabling a more compact structure.

[0077] Furthermore, since a sixth sealing space S6 is arranged inside the fifth sealing space S5, and an oil chamber S7 is arranged further inside the sixth sealing space S6, lubricating oil OL1 that is about to leak from the oil chamber S7 to the outside of the ship can be recovered in the low-pressure sixth sealing space S6. Moreover, since a high-pressure fifth sealing space S5 is arranged outside the sixth sealing space S6, the leakage of lubricating oil OL1 to the outside of the ship can be prevented.

[0078] Furthermore, since the 6th sealing space S6 is supplied with the same lubricating oil as the oil chamber S7, it does not matter even if there is leakage from the oil chamber S7 into the 6th sealing space S6.

[0079] Furthermore, since a low-pressure third sealed space S3, in which air A is introduced, is disposed between the fourth sealed space S4 and the second sealed space S2, even if lubricating oil or seawater leaks into the third sealed space S3, it can be recovered without concern about leakage to the outside of the ship. Moreover, the lubricating oil and seawater recovered in the third sealed space S3 can be discharged into the discharge container 42, thus preventing overflow from the third sealed space S3 into the fourth sealed space S4 or the second sealed space S2.

[0080] Furthermore, since the fifth sealing space S5 and the sixth sealing space S6 are adjacent, the sealing force of the fifth lip seal 25, which divides the fifth sealing space S5 and the sixth sealing space S6, is increased due to the pressure difference between the two spaces, thus effectively preventing lubricating oil leakage. Moreover, lubricating oil is less likely to leak from the gap between the fifth lip seal 25 and the sleeve 4, making pressure adjustment of the fifth sealing space S5 and the sixth sealing space S6 easier.

[0081] Furthermore, the sixth sealed space S6 can switch its connection with the discharge container 45 via an on / off valve, allowing lubricating oil OL4 to be discharged to the outside. Thus, the fluid pressure within the sixth sealed space S6 can be adjusted by opening and closing the on / off valve.

[0082] Furthermore, in the pressure reducing valve 30, the valve core 35 is forced towards the valve seat component 36 by the spring 34, so the opening is adjusted according to the change of the pressure difference between the fifth sealing space S5 and the sixth sealing space S6, and the pressure of the fifth sealing space S5 and the sixth sealing space S6 can be appropriately adjusted.

[0083] Furthermore, in this embodiment 1, the arrangement of the first sealing space S1 to the sixth sealing space S6 is illustrated, but it is sufficient to provide at least the fifth sealing space S5 and the sixth sealing space S6. Also, the fifth sealing space S5 may be located on the inner side of the ship, and the sixth sealing space S6 may be located on the outer side of the ship.

[0084] Furthermore, in this embodiment 1, the fifth sealing space S5 and the sixth sealing space S6 are shown to be adjacent, but it is also possible that different sealing spaces are formed between the fifth sealing space S5 and the sixth sealing space S6.

[0085] Furthermore, in this embodiment 1, a flow path 6 connecting the fifth sealing space S5 and the sixth sealing space S6 is exemplified in the housing 10. However, it is also possible to connect the fifth sealing space S5 and the sixth sealing space S6 by connecting a pipe provided outside the housing 10 to the opening of the housing.

[0086] Furthermore, in this embodiment 1, an example is shown of introducing the same lubricating oil as the oil chamber S7 into the fourth sealing space S4, the fifth sealing space S5, and the sixth sealing space S6, but it is not limited to this; a fluid different from the oil chamber S7 may also be introduced. In this case, it is preferable that the lip of the sixth lip seal 26 is configured to face the high-pressure side in the sixth sealing space S6 and the oil chamber S7.

[0087] Furthermore, the pressure reducing valve 30 is assembled from the outside of the housing 10 by screwing. This allows for easy assembly and replacement of the pressure reducing valve 30.

[0088] Furthermore, in the pressure reducing valve 30, the pressure adjusting rod 32 can be adjusted from outside the housing 10, thus making it easy to adjust the force of the spring 34.

[0089] Example 2

[0090] Next, refer to Figure 4 The stern tube sealing device of Example 2 will be described. Furthermore, repeated structural descriptions identical to those of Example 1 will be omitted.

[0091] like Figure 4 As shown, in this embodiment 2, the sealing device 201 is disposed on the bow side of the stern tube 100 to prevent lubricating oil in the oil chamber S7 from leaking from the stern tube 100 and the sleeve 204 externally fixed to the propeller shaft 2 into the ship's machinery room S9. The machinery room S9 is an atmospheric space.

[0092] The sealing device 201 mainly consists of a housing 210 as a cylindrical body, a first lip seal 221 to a third lip seal 223, and a pressure reducing valve 230 as a pressure adjusting device.

[0093] The hull 210 is formed into a generally cylindrical shape by integrally connecting the first segmented hull 210a, the second segmented hull 210b, the third segmented hull 210c, and the fourth segmented hull 210d from the bow side in an axially interlocking manner using bolts (not shown). In the hull 210, the flange of the fourth segmented hull 210d formed on the stern side is fixed to the stern tube 100 by bolts 7.

[0094] The outer diameter portion of the first lip seal 221 is sealed between the first segmented housing 210a and the second segmented housing 210b. The outer diameter portion of the second lip seal 222 is sealed between the second segmented housing 210b and the third segmented housing 210c. The outer diameter portion of the third lip seal 223 is sealed between the third segmented housing 210c and the fourth segmented housing 210d.

[0095] The lips of the first lip seal 221 to the third lip seal 223 face outwards from the ship.

[0096] A sealing space S11 is formed between the first lip seal 221 and the second lip seal 222. A sealing space S12 is formed between the second lip seal 222 and the third lip seal 223. The outer side of the third lip seal 223 is an oil chamber S7.

[0097] The second and third partition shells 210b and 210c are provided with flow paths 206 that connect the sealed spaces S11 and S12.

[0098] Furthermore, a pressure reducing valve 230 capable of opening and closing the flow path 206 is assembled in the third segment housing 210c. The pressure reducing valve 230 has a structure substantially the same as the pressure reducing valve 30 of Embodiment 1, therefore detailed description is omitted.

[0099] Furthermore, the sealed space S11 is connected to the discharge container 245. In addition, a throttling section 8 is provided in the flow path between the sealed space S11 and the discharge container 245.

[0100] Furthermore, the sealed space S12 is connected to the oil supply device 244. The oil supply device 244 continuously introduces lubricating oil at a pressure slightly lower than that of the oil chamber S7 into the sealed space S12.

[0101] The lubricating oil in the sealed space S12 is introduced into the sealed space S11 through the flow path 206, which is adjusted according to the pressure difference between the sealed spaces S11 and S12 by the opening of the pressure reducing valve 30. As a result, the pressure in the sealed space S11 becomes lower than the pressure in the sealed space S12.

[0102] That is, the fluid pressures are as follows: oil chamber S7 > sealing space S12 > sealing space S11 > mechanical chamber S9. Therefore, the pressure difference between oil chamber S7 and sealing space S12 improves the sealing performance of the third lip seal 223, the pressure difference between sealing space S12 and sealing space S11 improves the sealing performance of the second lip seal 222, and the pressure difference between sealing space S11 and mechanical chamber S9 improves the sealing performance of the first lip seal 221. Thus, lubricating oil leakage into mechanical chamber S9 can be prevented.

[0103] Example 3

[0104] Next, refer to Figure 5 The stern tube sealing device of Example 3 will be described. Furthermore, repeated structural descriptions identical to those in Example 1 will be omitted.

[0105] like Figure 5As shown, the sealing device 301 of this embodiment 3 is mainly composed of a housing 310 as a cylindrical body, a first lip seal 321 to a fourth lip seal 324, and pressure reducing valves 330A and 330B as pressure adjusting devices.

[0106] The hull 310 is formed into a generally cylindrical shape by integrally connecting the first segmented hull 310a, the second segmented hull 310b, the third segmented hull 310c, the fourth segmented hull 310d, and the fifth segmented hull 310e from the stern side in an axially interlocking state using bolts (not shown). Within the hull 310, the flange of the fifth segmented hull 310e formed on the stern side is fixed to the stern tube 100 by bolts 9.

[0107] The outer diameter portion of the first lip seal 321 is sealed between the first segmented housing 310a and the second segmented housing 310b. The outer diameter portion of the second lip seal 322 is sealed between the second segmented housing 310b and the third segmented housing 310c. The outer diameter portion of the third lip seal 323 is sealed between the third segmented housing 310c and the fourth segmented housing 310d. The outer diameter portion of the fourth lip seal 324 is sealed between the fourth segmented housing 310d and the fifth segmented housing 310e.

[0108] The lips of the first lip seal 321 to the third lip seal 323 face outwards from the ship. The lip of the fourth lip seal 324 faces inwards from the ship.

[0109] A sealing space S31 is formed between the first lip seal 321 and the second lip seal 322. A sealing space S32 is formed between the second lip seal 322 and the third lip seal 323. A sealing space S33 is formed between the third lip seal 323 and the fourth lip seal 324.

[0110] The second partition housing 310b and the third partition housing 310c are provided with flow paths 361 that connect the sealed spaces S31 and S32. Furthermore, the third partition housing 310c and the fourth partition housing 310d are provided with flow paths 362 that connect the sealed spaces S32 and S33.

[0111] A pressure reducing valve 330A capable of opening and closing the flow path 361 is assembled in the second segment housing 310b. A pressure reducing valve 330B capable of opening and closing the flow path 362 is assembled in the third segment housing 310c. Furthermore, the pressure reducing valves 330A and 330B have a substantially the same structure as the pressure reducing valve 30 of Embodiment 1, therefore detailed description is omitted.

[0112] Water W is sealed in the internal space S37 of the stern tube 100, which improves the lubrication of the bearing.

[0113] A water storage container 341 is disposed outside the internal space S37. This storage container 341 is connected to a pump 342. The pump 342 can pressurize the water in the storage container 341 and introduce it into the internal space S37 and the sealed space S31. In addition, in this embodiment 3, the pressure of the water W introduced into the sealed space S31 is lower than the pressure of the seawater SW in the external space S38.

[0114] Water W introduced into sealed space S31 is depressurized by pressure reducing valve 330A and introduced into sealed space S32. Water W introduced into sealed space S32 is depressurized by pressure reducing valve 330B and introduced into sealed space S33. That is, the pressure in each space is: outer space S38 > sealed space S31 > sealed space S32 > sealed space S33. Furthermore, the pressure in sealed space S33 is lower than the pressure in inner space S37.

[0115] Therefore, the sealing performance of the first lip seal 321 is improved by utilizing the pressure difference between the external space S38 and the sealed space S31; the sealing performance of the second lip seal 322 is improved by utilizing the pressure difference between the sealed spaces S31 and S32; the sealing performance of the third lip seal 323 is improved by utilizing the pressure difference between the sealed spaces S32 and S33; and the sealing performance of the fourth lip seal 324 is improved by utilizing the pressure difference between the sealed space S33 and the internal space S37. Thus, seawater SW can be prevented from flowing into the internal space S37.

[0116] Furthermore, the water W introduced into the sealed space S33 is discharged into the storage container 341. Also, the water W in the internal space S37 is discharged into the storage container 341.

[0117] Furthermore, in this embodiment 3, an example is shown where the pressure of the water W introduced into the sealed space S31 is lower than the pressure of the seawater SW in the outer space S38. However, it is also possible for the sealed space S31 and the outer space S8 to have the same pressure, or for the pressure of the water W introduced into the sealed space S31 to be higher than the pressure of the seawater SW in the outer space S38. This is because the water W is fresh water, so it is acceptable for it to be discharged into the outer space S38.

[0118] Furthermore, in this embodiment 3, a method in which three sealed spaces S31, S32, and S33 are connected is illustrated, but it is also possible for four or more sealed spaces to be connected.

[0119] Furthermore, in this embodiment 3, the pressure in each sealed space is gradually reduced towards the inside of the ship, but it is also possible that the pressure in each sealed space is reduced towards the outside of the ship.

[0120] The embodiments of the present invention have been described above based on the accompanying drawings, but the specific structure is not limited to these embodiments. Changes and additions that do not depart from the spirit of the present invention are also included in the present invention.

[0121] For example, in the aforementioned embodiments 1 to 3, seawater was used as the external fluid, but it can also be, for example, fresh water, oil, air, gas, etc., and can be freely changed. Furthermore, the internal fluid is not limited to lubricating oil and water, but can also be air, gas, etc.

[0122] Furthermore, in the aforementioned embodiments 1 to 3, the method of sliding contact between the lip seal and the outer peripheral surface of the sleeve embedded in the propeller shaft was described, but it is not limited to this. Alternatively, the sleeve may not be used, and the lip seal may directly slide in contact with the outer peripheral surface of the propeller shaft 2.

[0123] Furthermore, in the aforementioned embodiments 1 to 3, a pressure reducing valve was used as an example of a pressure regulating device, but it could also be a throttling mechanism such as a throttling section. Moreover, the pressure regulating device is not limited to providing pressure to the sealing space of one party by reducing pressure in the sealing space of another party; it could also provide pressure by increasing pressure.

[0124] Furthermore, pressure reducing valves are not limited to lift valves; they can also be spool valves, etc.

[0125] Furthermore, each sealing ring is not limited to being composed of a lip seal; for example, it can also be an end face seal.

[0126] Label Explanation

[0127] 1: Sealing device; 2: Propeller shaft (rotating shaft); 6: Flow path; 10: Housing (cylindrical body); 25: Fifth lip seal (sealing ring); 30: Pressure reducing valve (pressure adjusting device); 34: Spring; 35: Valve core; 36: Valve seat assembly; 41: Air inlet device; 42: Discharge container; 43: First oil supply device; 44: Second oil supply device; 45: Discharge container; 100: Stern pipe; S5: Fifth sealing space (one side's sealing space); S6: Sixth sealing space (the other side's sealing space); S7: Oil chamber; S8: External space.

Claims

1. A sealing device comprising: A cylindrical body through which a rotating shaft is inserted; and A sealing ring, which is installed on the cylindrical body, seals the space between the cylindrical body and the rotating shaft. The sealing device has at least two sealing spaces separated by the sealing ring. in, Sealing fluid is introduced from the outside into one of the sealed spaces. The sealing space of one party is connected to the sealing space of the other party through a flow path. A pressure adjusting device is provided in the flow path to adjust the pressure of the sealing fluid introduced into the sealing space of one party and then into the sealing space of the other party.

2. The sealing device according to claim 1, wherein, The flow path is formed in the cylindrical body.

3. The sealing device according to claim 1, wherein, The sealing space of the other party is located closer to the inside of the machine than the sealing space of the first party, and an oil chamber is located even closer to the inside of the machine in the sealing space of the other party.

4. The sealing device according to claim 1, wherein, The sealing space of one party is adjacent to the sealing space of the other party, and the sealing ring is a lip seal. The sealing force of the sealing ring is improved by utilizing the pressure difference between the sealing space of one party and the sealing space of the other party.

5. The sealing device according to claim 1, wherein, The fluid within the sealed space of the other party can be discharged to the outside.

6. The sealing device according to any one of claims 1 to 5, wherein, The pressure regulating device is a valve in which the valve core is stressed by a spring.

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