Sealing Device

Abstract

Provided is a seal device that can reliably prevent a fluid to be sealed from leaking out of an apparatus. The seal device 1 is provided with a first seal means 21 and a second seal means 23, and prevents entry of an external fluid W and leakage of a fluid to be sealed. The first seal means 21 is provided at a location of relative rotation of a first member 10 and a second member 2 that rotates relative to the first member 10, and faces the external fluid W. The second seal means 23 is provided along with the first seal means 21, and faces the fluid to be sealed in an apparatus. Between the first seal means 21 and the second seal means 23, an intermediate seal means 22 is provided along with the first seal means 21 and the second seal means 23. Between the first seal means 21 and the intermediate seal means 22, a gas chamber 31 is formed, to which is supplied a gas having a pressure higher than the external fluid W. Between the intermediate seal means 22 and the second seal means 23, an intermediate chamber 32 is formed, to which is supplied a gas having a pressure lower than the gas supplied to the gas chamber 31 and lower than the fluid to be sealed.

Description

[Technical Field]

[0001] The present invention relates to a sealing device that seals the relative rotation points of rotary machines that are used in ship propulsion machines, tidal current power generators, and the like. [Background technology]

[0002] Conventionally, sealing devices provided in rotary machines such as those used in ship propulsion units and tidal current power generators have been known to seal annular gaps formed at points of relative rotation to prevent sealed fluids inside the machine, such as lubricating oil, from leaking outside the machine and to prevent external fluids, such as seawater, from entering the machine.

[0003] For example, Patent Document 1 discloses a seal device used in a ship propulsion unit. The seal device is held in a housing having a shaft hole through which a propulsion shaft is inserted, and includes three seal rings arranged axially in a row, the seal rings sliding against the outer circumferential surface of a liner fitted around the shaft. Air is supplied to a primary annular chamber formed between a pair of the seal rings provided on the outboard side of the ship, and lubricating oil is supplied to a secondary annular chamber formed between a pair of the seal rings provided on the inboard side. Specifically, the amount of air supplied to the primary annular chamber is adjusted so that the internal pressure is maintained at the sum of seawater pressure and the clamping pressure of the seal rings, and the amount of lubricating oil supplied to the secondary annular chamber is adjusted so that the internal pressure is sufficient to blow the air supplied to the primary annular chamber through the seal rings outboard. This constantly adjusts the internal pressures of the primary and secondary annular chambers in response to fluctuations in seawater pressure, resulting in high responsiveness to fluctuations in seawater pressure and preventing seawater from entering the ship. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-304005 (page 4, Figure 2) Summary of the Invention [Problem to be solved by the invention]

[0005] However, the sealing device of Patent Document 1 prevents seawater from entering the ship by using the internal pressure of the secondary annular chamber to which lubricating oil is supplied to blow air from the primary annular chamber outboard.However, since the internal pressure of the secondary annular chamber is always adjusted to be higher than the internal pressure of the primary annular chamber, if a malfunction occurs in these seal rings, the high-pressure lubricating oil in the secondary annular chamber will enter the primary annular chamber through the seal ring, and the lubricating oil will be blown outboard from the primary annular chamber, where there is low pressure, together with the air, which could result in the lubricating oil leaking outboard.

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide a seal device that can reliably prevent the sealed fluid from leaking outside the machine. [Means for solving the problem]

[0007] In order to solve the above problems, the sealing device of the present invention comprises: The first member and the second member are provided at a relative rotation location, the second member rotating relative to the first member. a first sealing means facing an external fluid; and a second sealing means arranged in parallel with the first sealing means and facing a sealed fluid inside the aircraft; A sealing device for preventing intrusion of an external fluid and leakage of a sealed fluid, an intermediate sealing means is provided between the first sealing means and the second sealing means, and the intermediate sealing means is provided in parallel with the first sealing means and the second sealing means; a gas chamber is formed between the first seal means and the intermediate seal means to which gas having a higher pressure than the external fluid is supplied; An intermediate chamber is formed between the intermediate seal means and the second seal means to which gas having a lower pressure than the gas supplied to the gas chamber and a lower pressure than the sealed fluid is supplied. With this, even if a problem occurs in which the sealed fluid facing the second sealing means enters the intermediate chamber through this second sealing means, the sealed fluid can be retained in the intermediate chamber, which has a lower pressure than the gas chamber adjacent to the outside of the aircraft, so that leakage of the sealed fluid to the outside of the aircraft can be reliably prevented.

[0008] The second sealing means may be a lip seal, and may be arranged so that a lip portion thereof is pressed against the second member by the sealed fluid. According to this, the pressure of the sealed fluid, which is higher than the pressure of the gas in the intermediate chamber, can be used as the clamping pressure of the lip seal, so that the sealed fluid is less likely to enter the intermediate chamber.

[0009] The intermediate chamber may be in communication with the recovery chamber via a communication passage. According to this, the sealed fluid that has entered the intermediate chamber is recovered in the recovery chamber through the communicating passage, making it easier to discharge the sealed fluid in the intermediate chamber into the recovery chamber, which is a separate chamber, thereby further preventing the sealed fluid from leaking outside the machine.

[0010] The communication passage may be provided with a check valve for preventing backflow toward the intermediate chamber. This makes it possible to prevent the sealed fluid recovered in the recovery chamber from flowing back into the intermediate chamber through the communication passage.

[0011] The intermediate chamber may be supplied with a pressure-controlled compressed gas. This makes it possible to maintain an appropriate differential pressure between the gas supplied to the gas chamber and the sealed fluid.

[0012] The compressed gas may be compressed air. This makes handling easy and ensures safety.

[0013] The sealed fluid may be controlled to a lower pressure than the external fluid. This makes it difficult for the sealed fluid that has entered the intermediate chamber to leak out of the machine. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating a stern tube seal system using a seal device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged schematic view showing the sealing device in the first embodiment. [Figure 3] FIG. 6 is a schematic diagram illustrating a stern tube seal system using a seal device according to a second embodiment of the present invention. [Figure 4] FIG. 10 is an enlarged schematic view showing a sealing device in Example 2. [Figure 5] FIG. 10 is a schematic diagram illustrating a modified example of the stern tube seal system using the seal device in the second embodiment. [Figure 6] FIG. 10 is an enlarged schematic view showing a sealing device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealing device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0016] A sealing device according to a first embodiment will be described with reference to Figures 1 and 2. In this embodiment, a sealing device for a ship propulsion unit will be described as an example. In addition, the left side of Figures 1 and 2 will be the stern side (outboard side) of the sealing device, and the right side of Figures 1 and 2 will be the bow side (inboard side) of the sealing device. In Figures 2 and 4, hatching of the housing and the like is omitted, and the compressed air and lubricating oil supplied to and stored in each chamber are schematically shown by hatching.

[0017] As shown in FIG. 1 , the sealing device 1 according to the present invention is a shaft sealing device for a ship's propulsion unit. It is attached from the stern side to a stern tube 100 through which a propeller shaft 2 having a propeller 3 for propulsion is inserted. It is used to prevent leakage of lubricating oil, a sealed fluid supplied into the stern tube 100 that constitutes the hull for lubricating the propeller shaft 2 and a bearing (not shown), outside the ship, and to prevent seawater W, an external fluid, from entering the ship. The sealing device 1 is connected by pipelines to an air control unit 120, a lubricating oil circulation unit 130, and a recovery unit 140, all of which are provided on board, to form a stern tube sealing system. The sealing device 40 provided on board is attached from the bow side to the stern tube 100 and serves to prevent the lubricating oil supplied into the stern tube 100 from entering the machinery room. In this embodiment, the sealing device 1 on the stern side will be described, and a description of the sealing device 40 on the bow side will be omitted.

[0018] As shown in Figures 1 and 2, the sealing device 1 is provided at a relative rotation point between a housing 10 as a first member and a liner 4 constituting a propeller shaft 2 as a second member that rotates relative to the housing 10, and is mainly composed of a first lip seal 21 as a first sealing means facing the seawater W outside the ship, a second lip seal 23 as a second sealing means that is arranged in parallel with the first lip seal 21 on the inboard side and faces the lubricating oil that fills the oil chamber 33 in the stern tube 100, and an intermediate lip seal 22 as an intermediate sealing means that is arranged in parallel with the first lip seal 21 and the second lip seal 23.

[0019] 2, the housing 10 is formed into a generally cylindrical shape by, in order from the stern side, fitting a first split housing 10a, a second split housing 10b, a third split housing 10c, and a fourth split housing 10d together in the axial direction and connecting them together with bolts (not shown) or the like. The housing 10 is fixed with bolts (not shown) or the like with a flange portion formed on the bow-side fourth split housing 10d abutting against the stern tube 100 from the stern side.

[0020] In addition, in the housing 10, the outer diameter portion of the first lip seal 21 is held in an approximately sealed state between the first split housing 10a and the second split housing 10b, the outer diameter portion of the intermediate lip seal 22 is held in an approximately sealed state between the second split housing 10b and the third split housing 10c, and the outer diameter portion of the second lip seal 23 is held in an approximately sealed state between the third split housing 10c and the fourth split housing 10d.

[0021] In addition, the second split housing 10b, the third split housing 10c and the fourth split housing 10d have through holes that form part of the first air supply passage 11 that connects the air control unit 120 and the first annular chamber 31 as a gas chamber, and the second split housing 10b has a supply port 11a on the upper side of its inner surface that connects to the first air supply passage 11.

[0022] Furthermore, the third split housing 10c and the fourth split housing 10d are formed with through holes that form part of the second air supply passage 12 that communicates between the air control unit 120 and the second annular chamber 32 serving as an intermediate chamber, and the third split housing 10c is formed with a supply port 12a on the upper side of its inner circumferential surface that communicates with the second air supply passage 12. Furthermore, the third split housing 10c and the fourth split housing 10d are formed with through holes that form part of the communication passage 14 that communicates between the second annular chamber 32 and the recovery unit 140, and the third split housing 10c is formed with a discharge port 14a on the lower side of its inner circumferential surface that communicates with the communication passage 14.

[0023] 2, these lip seals 21, 22, 23 are made of an elastic material such as fluororubber or nitrile rubber, which has excellent water resistance and oil resistance. Note that the lip seals 21, 22, 23 of this embodiment have well-known configurations, so detailed description thereof will be omitted.

[0024] The lip seals 21, 22, 23 are arranged side by side in the axial direction with their outer diameter portions held in a substantially sealed state in the housing 10, and the inner peripheral surfaces of the lip portions 21a, 22a, 23a, which extend radially inward and axially toward the high-pressure side, are brought into sliding contact with the outer peripheral surface of the liner 4 fitted onto the propeller shaft 2, thereby forming a first annular chamber 31 between the first lip seal 21 and the intermediate lip seal 22, and a second annular chamber 32 between the intermediate lip seal 22 and the second lip seal 23. Furthermore, an annular oil chamber 33 is formed between the second lip seal 23 and the stern-side lip seal 41 of the bow-side sealing device 40.

[0025] The first annular chamber 31 is supplied with compressed air adjusted to a higher pressure than seawater W from the air control unit 120 via the first air supply passage 11. The second annular chamber 32 is supplied with compressed air adjusted to a lower pressure than the compressed air supplied from the air control unit 120 to the first annular chamber 31 via the second air supply passage 12 and to a lower pressure than the lubricating oil supplied from the lubricating oil circulation unit 130 to the oil chamber 33 in the stern tube 100.

[0026] The first lip seal 21 provided on the stern side of the first annular chamber 31 is arranged so that its lip portion 21a faces outboard, and the seawater pressure P W acts as part of the fastening pressure on the lip portion 21a. The intermediate lip seal 22 provided on the bow side of the first annular chamber 31 and on the stern side of the second annular chamber 32 is arranged so that its lip portion 22a faces outboard, i.e., toward the first annular chamber 31, and the air pressure P1 in the first annular chamber 31 acts as part of the fastening pressure on the lip portion 22a. The second lip seal 23 provided on the bow side of the second annular chamber 32 is arranged so that its lip portion 23a faces inboard, i.e., toward the stern tube 100, and the oil pressure P1 in the oil chamber 33 in the stern tube 100 O acts as part of the clamping pressure on the lip portion 23a.

[0027] Next, the air control unit 120, the lubricating oil circulation unit 130, and the recovery unit 140 which together with the sealing device 1 constitute the stern tube sealing system will be described.

[0028] As shown in FIG. 1, the air control unit 120 is a unit that supplies compressed air, which is supplied from a compressor (not shown) installed on board the ship and whose pressure is adjusted by a pressure reducing valve, a flow control valve, etc. (not shown), through the first air supply path 11, the second air supply path 12, or the third air supply path 13, to the first annular chamber 31, the second annular chamber 32, or the lubricating oil tank 131 of the lubricating oil circulation unit 130 described later. Specifically, the air control unit 120 controls the seawater pressure P W In response to this, the air pressure P1 in the first annular chamber 31 is always kept equal to the seawater pressure P W Adjust so that it exceeds Furthermore, seawater pressure P W varies depending on the draft of the ship, and the air control unit 120 controls the seawater pressure P W The air pressure is adjusted to follow the fluctuations of the seawater pressure P W A signal corresponding to the pressure in the first air supply passage 11 and the first annular chamber 31 is output to a pressure reducing valve 122, which is a part of an air control unit 120 provided at a branch point of the first air supply passage 11 and the second air supply passage 12. When passing through the pressure reducing valve 122, a part of the compressed air is supplied to the first annular chamber 31 based on the output signal at a pressure lower than the air pressure P1 of the compressed air supplied to the first annular chamber 31 and higher than the oil pressure P of the lubricating oil supplied to the oil chamber 33 in the stern tube 100. O The compressed air is supplied to the second annular chamber 32 through the second air supply passage 12 at an air pressure P2 that is reduced to a pressure P2 that is lower than the air pressure P1 by a predetermined differential pressure.

[0029] The lubricating oil circulation unit 130 is a unit that circulates lubricating oil by supplying lubricating oil from a lubricating oil tank 131 provided on board the ship through a first lubricating oil circulation path 132 into the stern tube 100 using a pump 134, and returning the lubricating oil from the stern tube 100 through a second lubricating oil circulation path 133 to the lubricating oil tank 131 again. W A signal corresponding to the signal is output to a pressure reducing valve 123, which is a part of an air control unit 120 provided at a branching point of the first air supply passage 11 and the third air supply passage 13, and when passing through the pressure reducing valve 123, a part of the compressed air has a pressure higher than the air pressure P2 of the compressed air supplied to the second annular chamber 32 based on the output signal and is equal to or higher than the seawater pressure P W After the pressure is adjusted to be equal to or lower by a predetermined differential pressure than the pressure in the lubricating oil tank 131, the lubricating oil is supplied to the lubricating oil tank 131 through the third air supply passage 13. Therefore, the oil pressure P O The compressed air thus decompressed comes into contact with the oil surface as a boundary surface, and the pressure P2 of the second annular chamber 32 is higher than the air pressure P2 of the second annular chamber 32 and is equal to the seawater pressure P W It is adjusted to a pressure lower than or equal to that of the

[0030] That is, seawater pressure P W , the air pressure P1 in the first annular chamber 31, the air pressure P2 in the second annular chamber 32, and the oil pressure P O Air pressure P1>Seawater pressure P W ≧Hydraulic pressure P O > Air pressure P2 is adjusted to be always satisfied.

[0031] The recovery unit 140 is a unit that recovers lubricating oil to a recovery chamber 141 provided inside the ship through the communication passage 14 in the event of a malfunction in which lubricating oil enters the second annular chamber 32 from the oil chamber 33 in the stern tube 100. In addition, a check valve 142 is provided in the communication passage 14 to prevent the lubricating oil recovered in the recovery chamber 141 from flowing back into the second annular chamber 32.

[0032] In this way, in the sealing device 1 of this embodiment, compressed air reduced in pressure to air pressure P2 by the air control unit 120 is supplied to the second annular chamber 32 through the second air supply passage 12 so that the air pressure is lower than the air pressure P1 of the compressed air supplied to the first annular chamber 31 through the first air supply passage 11.Therefore, even if a problem occurs in which lubricating oil in the oil chamber 33 facing the second lip seal 23 enters the second annular chamber 32 through the second lip seal 23, the lubricating oil that has entered the second annular chamber 32, which has an air pressure P2 lower than that in the first annular chamber 31 adjacent to the outboard side, can be retained, and leakage of lubricating oil overboard can be reliably prevented.

[0033] Furthermore, since the lip portion 22a of the intermediate lip seal 22 provided on the stern side of the second annular chamber 32 is positioned facing the first annular chamber 31, the lip portion 22a of the intermediate lip seal 22 is pressed inward toward the outer surface of the liner 4 and sealed by the pressure difference between the air pressure P1 in the first annular chamber 31 and the air pressure P2 in the second annular chamber 32, thereby preventing lubricating oil that has entered the second annular chamber 32 from entering the first annular chamber 31 and further preventing the lubricating oil from leaking overboard.

[0034] Furthermore, even if a problem occurs in which the lubricating oil in the oil chamber 33 in the stern tube 100 enters the second annular chamber 32 through the second lip seal 23, the lubricating oil that has entered the second annular chamber 32 is recovered in the recovery chamber 141 inside the ship through the connecting passage 14, making it easier to discharge the lubricating oil from the second annular chamber 32, thereby better preventing the lubricating oil from leaking outside the ship.

[0035] The lubricating oil supplied from the lubricating oil circulation unit 130 to the oil chamber 33 in the stern tube 100 is W The oil pressure P O is the seawater pressure P W Since the pressure is controlled to be lower than the pressure in the second annular chamber 32, even if lubricating oil enters the second annular chamber 32, it is unlikely to leak out of the ship.

[0036] Furthermore, the compressed air supplied from the air control unit 120 to the second annular chamber 32 is reduced in pressure by a preset differential pressure lower than the lubricating oil supplied to the oil chamber 33 in the stern tube 100, so that the lip portion 23a of the second lip seal 23 is pressed radially inward toward the outer circumferential surface of the liner 4 by the differential pressure between the second annular chamber 32 and the oil chamber 33, thereby forming a seal, thereby preventing the lubricating oil supplied into the oil chamber 33 from entering the second annular chamber 32. Furthermore, the compressed air supplied to the second annular chamber 32 can also be prevented from entering the oil chamber 33.

[0037] In addition, pressure-adjusted compressed air is supplied to the second annular chamber 32 via the air control unit 120, and the differential pressure between the compressed air supplied to the first annular chamber 31 and the lubricating oil supplied to the oil chamber 33 can be maintained at an appropriate level.As a result, the load on the intermediate lip seal 22 and the second lip seal 23 that make up the second annular chamber 32 can be maintained approximately constant, thereby extending their service life.

[0038] Furthermore, compressed air is supplied to the first annular chamber 31 and the second annular chamber 32 via the air control unit 120, making handling easy and ensuring safety.

[0039] In addition, the seawater pressure P W Since the compressed air whose pressure is adjusted to the above air pressure P1 is supplied to the first annular chamber 31 through the first air supply passage 11, the intrusion of seawater W into the first annular chamber 31 from between the lip portion 21a of the first lip seal 21 and the liner 4 is prevented. Furthermore, the air of the air pressure P1 supplied to the first annular chamber 31 is W The air is blown out of the ship from between the lip portion 21a of the first lip seal 21 and the liner 4 against the seawater pressure P W Since it is possible to detect fluctuations in the temperature, there is no need to install additional detection tanks or piping.

[0040] The air pressure P2 in the second annular chamber 32 is set to the seawater pressure P W By setting the oil pressure P OThe seawater pressure P W Since the lubricating oil pressure can be reduced to less than 1 / 2, there is no need to install pump equipment for increasing the pressure of the lubricating oil or the lubricating oil tank 131 at a high location, and the entire stern tube seal system can be simplified.

[0041] It is preferable that a pressure control valve such as a pressure reducing valve or a relief valve be installed in the second annular chamber 32 so that excess pressure can be discharged if high-pressure compressed air enters from the first annular chamber 31, thereby preventing air from entering the oil chamber 33. [Example]

[0042] Next, a sealing device according to a second embodiment will be described with reference to Figures 3 and 4. Note that the same components as those shown in the previous embodiment will be given the same reference numerals and redundant description will be omitted.

[0043] A seal device 201 in Example 2 will be described. As shown in Fig. 3, the seal device 201 is provided at a relative rotation location between a housing 210 as a first member and a liner 4 constituting a propeller shaft 2 as a second member that rotates relative to the housing 210, and is mainly composed of a first lip seal 21, an intermediate lip seal 22, a second lip seal 23, and an auxiliary lip seal 24 provided in parallel with the second lip seal 23 on the bow side.

[0044] As shown in Figure 4, the housing 210 is formed into an approximately cylindrical shape by, in order from the stern side, fitting the first split housing 10a, the second split housing 10b, the third split housing 10c, the fourth split housing 210d, and the fifth split housing 210e together in the axial direction and connecting them together with bolts or the like (not shown).

[0045] In addition, the outer diameter portion of the auxiliary lip seal 24 is held in a substantially sealed state between the fourth divided housing 210d and the fifth divided housing 210e in the housing 210. In addition, an annular second oil chamber 34 is formed between the second lip seal 23 and the auxiliary lip seal 24.

[0046] Furthermore, the fourth split housing 210d and the fifth split housing 210e are formed with through holes that form part of a branch communication passage 234 that branches off from the first lubricant oil circulation path 132 extending from the lubricant oil circulation unit 130 and communicates with the second oil chamber 34, and the fourth split housing 210d is formed with a supply port 234a on the lower side of its inner circumferential surface that communicates with the branch communication passage 234. An open / close valve 235 is provided in the branch communication passage 234. The lubricant oil tank 131 that constitutes the lubricant oil circulation unit 130 is configured as a pressurized tank that can adjust the pressure of the lubricant oil using the pressure of compressed air supplied from the air control unit 120 through the third air supply path 13.

[0047] The second lip seal 23 provided on the stern side of the second oil chamber 34 is arranged so that its lip portion 23a faces the inboard side, i.e., the second oil chamber 34 side, and the oil pressure P O2 acts as part of the tightening pressure on the lip portion 23a. The auxiliary lip seal 24 provided on the bow side of the second oil chamber 34 is arranged so that its lip portion 24a faces the inboard side, i.e., the stern tube 100 side. O1 acts as part of the clamping pressure on the lip portion 24a.

[0048] According to this, in the sealing device 201 of this embodiment, the lip portion 23a of the second lip seal 23 is disposed so as to face the second oil chamber 34, and therefore the lip portion 23a of the second lip seal 23 is pressed radially inward toward the outer circumferential surface of the liner 4 by the pressure difference between the second annular chamber 32 and the second oil chamber 34, thereby sealing, and therefore it is possible to prevent the lubricating oil supplied to the second oil chamber 34 from entering the second annular chamber 32. Furthermore, the lubricating oil supplied to the second oil chamber 34 from the lubricating oil circulation unit 130 through the branched communicating passage 234 is sealed by the second lip seal 23, and the hydraulic pressure P O2 The oil pressure P in the oil chamber 33 O1 Above (hydraulic P O2 ≧Hydraulic pressure P O1), the lubricating oil can flow out from between the lip portion 24a of the auxiliary lip seal 24 and the liner 4 into the oil chamber 33, and the lubricating oil supplied to the second oil chamber 34 is less likely to enter the second annular chamber 32. The lubricating oil that flows out from the second oil chamber 34 into the oil chamber 33 returns to the lubricating oil tank 131 through the second lubricating oil circulation path 133.

[0049] In addition, by providing an opening / closing valve 235 in the branch communication passage 234, for example, if the second lip seal 23 is damaged, the supply of lubricating oil to the second oil chamber 34 can be stopped by closing the opening / closing valve 235, and the lubricating oil can be switched to being sealed mainly by the auxiliary lip seal 24.

[0050] Furthermore, the lubricant oil tank constituting the lubricant oil circulation unit is not limited to being configured as a pressurized tank in which the pressure of the lubricant oil can be adjusted by the pressure of the compressed air supplied from the air control unit 120. For example, as a modified example of the stern tube sealing system using the sealing device 201 in this embodiment 2, the lubricant oil tank 231 constituting the lubricant oil circulation unit 230 may be configured as a gravity tank that supplies lubricant oil at a constant pressure by gravity, as shown in Fig. 5. The lubricant oil circulation unit 230 shown in Fig. 5 may be applied to the stern tube sealing system using the sealing device 1 in the above-mentioned embodiment 1. [Example]

[0051] Next, a sealing device according to a third embodiment will be described with reference to Fig. 6. Components that are the same as those shown in the previous embodiments will be assigned the same reference numerals, and duplicated descriptions will be omitted. In this embodiment, a sealing device for a center-open type tidal current power generator will be described as an example. In addition, the left side of Fig. 6 will be the inner diameter side of the sealing device, and the right side of Fig. 6 will be the outer diameter side of the sealing device.

[0052] A sealing device 301 in a third embodiment will now be described. As shown in Figure 6, the sealing device 301 for a center-open type tidal current power generator is used to prevent leakage of lubricating oil supplied inside the generator to lubricate a pair of bearings 304, 304 provided between an annular rotor 302 having a plurality of blades 303 on its inner circumferential surface and an annular power generating unit 307 having a coil 306 and arranged on the outer diameter side of the rotor 302, and to prevent seawater W from entering the generator. The rotor 302 is provided with magnets 305 along the circumferential direction of its outer circumferential surface, and power generation is generated when the rotor 302 receives the tidal current at its blades 303 and rotates relative to the power generating unit 307.

[0053] The sealing device 301 is mainly composed of a pair of annular housings 310, 310 as first members attached from the inner diameter side to a pair of annular casings 300, 300 arranged in front of and behind the rotor 302 and the power generation unit 307, a pair of annular first lip seals 321, 321 as first sealing means provided at the relative rotation point with the rotor 302 as a second member that rotates relative to the housings 310, 310 and faces the seawater W, a pair of second lip seals 323, 323 arranged in parallel with the first lip seals 321, 321 respectively and as second sealing means facing the lubricating oil inside the aircraft, and intermediate lip seals 322, 322 as intermediate sealing means arranged in parallel between the first lip seals 321, 321 and the second lip seals 323, 323 respectively.

[0054] 6, the housings 310, 310 are formed into a substantially cylindrical shape by fitting together a first divided housing 310a, a second divided housing 310b, a third divided housing 310c, and a fourth divided housing 310d, in that order from the inner diameter side, and connecting them together with bolts or the like (not shown). The housings 310, 310 are fixed with bolts or the like (not shown) with flanges formed on the first divided housings 310a, 310a on the inner diameter side fitted against the inner circumferential surfaces of the casings 300, 300, respectively.

[0055] In each of the housings 310, 310, one end of a first lip seal 321 is held in a substantially sealed state between the first divided housing 310a and the second divided housing 310b, one end of an intermediate lip seal 322 is held in a substantially sealed state between the second divided housing 310b and the third divided housing 310c, and one end of a second lip seal 323 is held in a substantially sealed state between the third divided housing 310c and the fourth divided housing 310d. A first annular chamber 331 is formed between the first lip seal 321 and the intermediate lip seal 322, and a second annular chamber 332 is formed between the intermediate lip seal 322 and the second lip seal 323. An annular oil chamber 333 is formed between the second lip seal 323 and the bearing 304.

[0056] Further, second split housings 310b, 310b are formed with through holes that form part of first air supply passages 311, 311 that communicate between air control unit 120 provided inside the aircraft and first annular chambers 331, 331 serving as gas chambers.

[0057] Further, third divided housings 310c, 310c are formed with through holes that form part of second air supply passages 312, 312 that communicate between air control unit 120 and second annular chambers 332, 332 serving as intermediate chambers.

[0058] In this way, in the sealing device 301 of this embodiment, compressed air reduced in pressure to P2 by the air control unit 120 is supplied to the second annular chamber 332, 332 through the second air supply passage 312, 312 so that the air pressure is lower than the air pressure P1 of the compressed air supplied to the first annular chamber 331, 331 through the first air supply passage 311, 311.Therefore, even if a malfunction occurs in which lubricating oil in the oil chamber 333 inside the aircraft facing the second lip seal 323, 323 enters the second annular chamber 332, 332 through the second lip seal 323, 323, the lubricating oil that has entered the second annular chamber 332, 332, which has an air pressure P2 lower than that in the first annular chamber 331, 331 adjacent to the outside of the aircraft, can be retained, and leakage of lubricating oil overboard can be reliably prevented.

[0059] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0060] For example, it goes without saying that the sealing device in the above-described embodiment can recover not only lubricating oil but also seawater W that has entered from outside the aircraft in the second annular chamber serving as the intermediate chamber. Furthermore, the external fluid is not limited to seawater, but may be, for example, fresh water. Furthermore, the sealed fluid is not limited to lubricating oil.

[0061] In the above embodiment, the air control unit 120 is described as being configured to reduce the pressure of compressed air using the pressure reducing valves 122 and 123, but this is not limiting, and various pressure control valves such as relief valves may be used to reduce the pressure of compressed air. Furthermore, the compressed gas is not limited to compressed air.

[0062] Furthermore, in the first and second embodiments, the lip seal is in sliding contact with the outer peripheral surface of the liner 4 fitted onto the propeller shaft 2, but the present invention is not limited to this, and the lip seal may be in direct sliding contact with the outer peripheral surface of the propeller shaft 2. Furthermore, in the above embodiments, each sealing means is not limited to being constituted by a lip seal.

[0063] Furthermore, in the third embodiment, the sealing device 301 applied to a center-open type tidal power generator was described, but the sealing device having the configuration of the first or second embodiment may also be applied to, for example, a turbine type tidal power generator. [Explanation of symbols]

[0064] 1 Sealing device 2 Propeller shaft (second member) 4 Liner 10 Housing (first member) 11 First air supply passage 12 Second air supply passage 13 Third air supply passage 14 Communication path 21 First lip seal (first sealing means) 22 Intermediate lip seal (intermediate sealing means) 23 Second lip seal (second sealing means) 24 Auxiliary lip seal 31 First annular chamber (gas chamber) 32 Second annular chamber (intermediate chamber) 33 Oil room 34 2nd oil room 100 Stern tube 120 Air Control Unit 122,123 Pressure reducing valve 130 Lubricating Oil Circulation Unit 131 Lubricating Oil Tank 132 1st lubricating oil circulation path 133 2nd lubricating oil circulation path 134 Pump 140 Recovery Unit 141 Recovery Room 142 Check valve 201 Sealing device 210 Housing (first member) 230 Lubricating Oil Circulation Unit 231 Lubricating Oil Tank 234 Branching Passage 300 casing 301 Sealing device 302 Rotor (second member) 307 Power Generation Unit 310 Housing (first member) 311 First air supply passage 312 Second air supply passage 321 First lip seal (first sealing means) 322 Intermediate lip seal (intermediate sealing means) 323 Second lip seal (second sealing means) 331 First annular chamber (gas chamber) 332 Second annular chamber (intermediate chamber) 333 Oil room

Claims

1. provided at a relative rotation location between a first member and a second member that rotates relative to the first member, a first sealing means facing an external fluid; and a second sealing means arranged in parallel with the first sealing means and facing a sealed fluid inside the aircraft; A sealing device for preventing intrusion of an external fluid and leakage of a sealed fluid, an intermediate seal means is provided between the first seal means and the second seal means, and the intermediate seal means is provided in parallel with the first seal means and the second seal means; a gas chamber is formed between the first seal means and the intermediate seal means, and a gas having a higher pressure than the external fluid is supplied from a first supply path; an intermediate chamber is formed between the intermediate sealing means and the second sealing means, into which gas having a pressure lower than that of the gas supplied to the gas chamber and lower than that of the sealed fluid is supplied from a second supply path separate from the first supply path; The intermediate chamber and the gas chamber are provided adjacent to each other.

2. 2. The sealing device according to claim 1, wherein the second sealing means is a lip seal, and is arranged so that a lip portion thereof is pressed against the second member by the sealed fluid.

3. 3. The sealing device according to claim 1, wherein the intermediate chamber is connected to the recovery chamber via a communication passage.

4. 4. The sealing device according to claim 3, wherein the communication passage is provided with a check valve for preventing backflow toward the intermediate chamber.

5. 5. A sealing device according to claim 1, wherein a pressure-controlled compressed gas is supplied to the intermediate chamber.

6. The sealing device according to claim 5, wherein the compressed gas is compressed air.

7. 7. A seal device according to claim 1, wherein the sealed fluid is controlled to a pressure lower than that of the external fluid.

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