JP3668709B2 - Seal device for pod propeller propulsion system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealing device for a pod propeller propulsion system.
[0002]
[Prior art]
In recent years, the power generated by the diesel engine in the hull is converted into an electric signal by an electric propulsion system, and this signal is transmitted by wire to an electric motor in a pod that is rotatably mounted on the stern part of the hull. A pod propeller propulsion system that rotates a propeller with a connected propeller shaft (for example, the product name “Adipod” from ABB Adipod) has been attracting attention. According to this system, the pod can be rotated outside the hull. There are various advantages such as no need for a steering machine and enhanced steering performance, electric propulsion can reduce noise and vibration in the ship, and the degree of freedom in design such as placing the engine on the bow side of the hull. It is said that there is.
[0003]
Of course, such a pod propeller propulsion system also requires a sealing device. In this case, the sealing device includes a pod that is provided on a floating structure such as a hull so as to be rotatable about a longitudinal axis, and a rear side of the pod. A cylindrical casing connected to the propeller shaft, a propeller shaft that is coaxially inserted into the casing and connected to an electric motor disposed in the pod, and slidably contacts the outer peripheral surface of the shaft to allow external water to flow. The thing provided with the some seal ring to seal is employ | adopted.
By the way, recently, due to an increase in the draft pressure accompanying the increase in size of the ship, there is a problem that the seal ring is damaged early and the lubricating oil leaks out of the ship, which leads to environmental pollution.
[0004]
Therefore, as a stern tube sealing device adopted in a normal marine vessel propulsion system that is not the pod propeller propulsion system, pressurized air is introduced into an air chamber partitioned between a pair of adjacent seal rings among a plurality of seal rings. The air is constantly blown out from the chamber toward the outboard water (see Japanese Utility Model Publication No. 5-35249, Japanese Patent Application Laid-Open No. 11-304005), and changes in response to fluctuations in draft pressure. By supplying pressurized air that is lower than the water pressure by a predetermined differential pressure into the air chamber (see Japanese Patent No. 2778899), the sliding load acting on the lip portion of the seal ring is reduced, and the durability of the seal ring is reduced. There is known an air seal type stern tube sealing device that improves the performance.
[0005]
[Problems to be solved by the invention]
Even in the conventional pod propeller propulsion system, it is necessary to overcome the problem that when the draft pressure increases as the size of the ship increases, the seal ring is damaged early and the lubricating oil leaks out of the ship, leading to environmental pollution. is there. Therefore, if the above-mentioned air seal type stern tube sealing device, which has been adopted in ordinary ship propulsion systems, is applied to the rear part of the pod that constitutes the pod propeller propulsion system, the durability of the seal ring can be improved. Conceivable.
[0006]
However, since the pod of the pod propeller propulsion system contains an electric motor that is vulnerable to water and a radial bearing that is easily corroded by seawater, the conventional air seal type stern tube sealing device was simply applied to the tail part of the pod. Alone, the pod propeller propulsion system can be fatally damaged.
In other words, when the air chamber partitioned in the tail part of the pod is pressurized to a level where air blows out from it or slightly lower than the draft pressure, the inside of the pod is also applied from the seal ring on the front side constituting the chamber. Because it is easy to blow out compressed air, external water that has entered the air chamber leaks into the pod together with the pressurized air, and this leaked water increases the risk of electric motor failure and corrosion of radial bearings. New challenges arise.
[0007]
In view of such circumstances, the present invention adopts an air seal type sealing device in a pod propeller propulsion system, and an air chamber provided on the rear side of the pod while effectively preventing external water from leaking into the pod. The purpose is to improve the durability of the seal ring without causing failure or corrosion of the internal equipment of the pod.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention takes the following technical means.
That is, the present invention provides a first air supply means for supplying pressurized air into an air chamber defined between a pair of adjacent seal rings among a plurality of seal rings in the sealing device of the pod propeller propulsion system described above. And second air supply means for supplying pressurized air that changes in response to fluctuations in draft pressure in a state higher than the air pressure in the air chamber into the pod.
[0009]
According to the present invention described above, the first air supply means supplies pressurized air into the air chamber inside the casing connected to the rear side of the pod. Therefore, the lip portion of the seal ring that defines the air chamber The sliding load acting on the surface is reduced, and the durability of the seal ring is improved.
On the other hand, since the second air supply means supplies pressurized air that changes in response to fluctuations in draft pressure in a state higher than the air pressure in the air chamber, the lip of the seal ring as described above. By reducing the sliding load acting on the part, even if external water enters the air chamber, it is effectively prevented that the external water leaks into the pod.
[0010]
Thus, according to the present invention, while the second air supply means effectively prevents external water from leaking into the pod, the first air supply means adds to the air chamber provided on the rear side of the pod. By supplying compressed air, the sliding load acting on the lip part of the seal ring can be reduced, which can improve the durability of the seal ring without causing failure or corrosion of the internal equipment of the pod. it can.
Hereinafter, more preferred embodiments of the present invention will be described based on the contents of the dependent claims.
[0011]
In the present invention, in order to improve the life of the seal ring more reliably, it is necessary to lubricate the lip portion of the seal ring with a lubricating material such as grease or lubricating oil.
Therefore, a lubrication chamber is formed between a seal ring on the front side of the pair of seal rings that divides the air chamber and a seal ring disposed on the front side, and a lubricating liquid is contained in the lubrication chamber. It is recommended to provide a liquid supply means for supplying the liquid.
[0012]
If such a liquid supply means is provided, it is expected that the lubricating liquid and external water will leak into the air chamber, so a drain circuit for collecting them in the floating structure should be connected to the air chamber. Is preferred.
On the other hand, in order to keep the seal ring on the rear side of one of the seal rings defining the air chamber lubricated, the seal ring is defined between the seal ring and the seal ring disposed on the rear side. It is preferable to fill the lubrication chamber with a lubricant having such a high viscosity that the pressurized air blown out from the air chamber is not blown off to the rear side.
[0013]
In this case, since the lubricant in the lubrication chamber located on the rear side of the air chamber has such a high viscosity that it is not blown off to the rear side, the pressure of the pressurized air is increased to the extent that air is blown out from the air chamber. In this case, the lubricant is not scattered outside, and environmental pollution can be prevented. In addition, when the lubricant in the lubrication chamber is highly viscous as described above, it is not necessary to add a seal ring on the rear side to prevent oil leakage. There is also an advantage that can be made.
[0014]
In the present invention, when a sealing device that blows pressurized air through a seal ring is employed, a first compressed air source and a pair of seal rings that divide the air chamber are used as the first air supply means. An air control unit that sets the pressure of the compressed air from the compressed air source to such an extent that air is blown out from the rear side seal ring, and the compressed air that has passed through the air control unit is supplied to the air chamber. What is necessary is just to employ | adopt what is provided with the air piping led to.
In this case, since air is constantly blown out from the air chamber, the second compressed air source is used as the second compressed air source as the second compressed air source as the second compressed air source. If an air relay that sets the pressurized air of the air relay to a predetermined output pressure and a pressurized pipe that applies the output pressure set by the air relay into the pod is adopted, the output pressure of the air relay By setting the air pressure higher than the air pressure in the air chamber, it is possible to supply pressurized air that changes in response to fluctuations in the draft pressure in the pod in a state higher than the air pressure in the air chamber.
[0015]
In the present invention, when a seal device of a type that can change the air pressure in the air chamber is employed, the first compressed air source and the pressurized air from the compressed air source are used as the first air supply means. An air control unit that sets the air to a predetermined pressure and flow rate, a detection pipe that detects the draft pressure by blowing the pressurized air that has passed through the air control unit directly into the external water without passing through the seal ring, A first air relay that sets the pressurized air from the first compressed air source to a predetermined output pressure using the air pressure in the detection pipe as a pilot pressure, and the output pressure set by the first air relay as the air chamber What is necessary is just to employ | adopt what is provided with the air piping applied inside.
[0016]
In this case, if the output pressure of the first air relay is set higher than the air pressure in the detection pipe by an amount corresponding to the tightening force of the garter spring, the air pressure inside the air chamber can be set to the extent that air blows out. On the other hand, if the output pressure of the first air relay is set to a value approximately equal to or slightly lower than the air pressure in the detection pipe, pressurized air will not blow out from the air chamber. There is an advantage that leakage can be prevented and air consumption can be reduced.
[0017]
In this case, since it is also possible to perform control so that air does not always blow out from the air chamber, the second air supply means includes a second compressed air source, and a detection pipe. A second air relay that sets the pressurized air from the second compressed air source to a predetermined output pressure using the air pressure as a pilot pressure, and an application that applies the output pressure set by the second air relay to the pod. If the one with pressure piping is adopted, the output pressure of the second air relay is set higher than the air pressure in the air chamber, so that the draft pressure fluctuates in a state higher than the air pressure in the air chamber. Correspondingly changing pressurized air can be fed into the pod.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of a sealing device 1 according to the present invention.
As shown in FIG. 1, the sealing device 1 of this embodiment is used for a pod propeller propulsion system 2, and this propulsion system 2 has a vertical axis at the stern portion of a hull 3 which is an example of a floating structure. A pod 4 rotatably provided around, a cylindrical casing 5 connected to the rear side of the pod 4, and an electric motor inserted coaxially into the casing 5 and disposed in the pod 4 6 and a propeller shaft 7 connected to 6.
[0019]
The front side end portion (right side end portion in FIG. 1) of the shaft 7 is supported by a thrust bearing 8 disposed at the front portion of the pod 4 so as to be rotatable and not moved in the axial direction. The rear side end (left side end in FIG. 1) is rotatably supported by a radial bearing 9 disposed at the rear end of the pod 4. The rear side end of the shaft 7 protrudes outside the pod 4, and the propeller 10 is fixed to the protruding end.
The sealing device 1 of the present embodiment is an external sealing device arranged outside the rear side of the pod 4, whereas the internal sealing device 11 is provided in a portion between the radial bearing 9 and the motor 6 in the pod 4. Is provided.
[0020]
As shown in FIG. 2, the sealing device 1 includes a pod 4 provided at the bottom of the hull 3 so as to be rotatable about a longitudinal axis, a cylindrical casing 5 connected to the rear side of the pod 4, A propeller shaft 7 inserted coaxially into the casing 5 and connected to an electric motor 6 disposed in the pod 4, and a plurality of sealing members for sealing the external water W in sliding contact with the outer peripheral surface of the shaft 7. And seal rings 12 to 15.
Among these, the propeller shaft 7 is composed of a shaft main body 16 directly connected to the motor 6 and a cylindrical liner 17 attached to an axial portion corresponding to the casing 5 in the shaft main body 16. The lip portion of each of the seal rings 12 to 15 whose base end portion is fixed to the inner peripheral surface of the casing 5 is in sliding contact with the outer peripheral surface of the liner 17. Note that the shaft 7 can be configured by only the shaft body 16 without providing the liner 17.
[0021]
In this embodiment, a total of four seal rings 12 to 15 are provided in the casing 5 so as to define the air chamber 20 and the lubrication chambers 21 and 22 on both the front side and the rear side.
Among these, the first seal ring 12 on the most rear side (the left side in FIG. 2) and the second seal ring 13 positioned on the front side are arranged so that the tip edge of the lip portion faces the rear side. The third seal ring 14 is the third seal ring 14 counted from the rearmost side and the fourth seal ring 15 is located one front side of the third seal ring 14, and the tip edge of the lip portion is on the front side (FIG. 2). The right side of the Ring-shaped garter springs 23 are wound around the lip portions of all the seal rings 12 to 15.
[0022]
The chamber defined between the second seal ring 13 and the third seal ring 14 is an air chamber 20 whose interior is pressurized with pressurized air, and a pair of seals defining the air chamber 20. A chamber defined between the second seal ring 13 on the rear side of the rings 13 and 14 and the first seal ring 12 disposed further on the rear side thereof is filled with a highly viscous lubricant 24 inside. The first lubrication chamber 21 is used.
That is, the inside of the first lubrication chamber 21 is filled with a lubricant 24 made of grease or the like having such a high viscosity that it is not blown off to the rear side by the pressurized air blown out from the air chamber 20.
[0023]
Further, the chamber defined between the third seal ring 14 on the front side of the pair of seal rings 13 and 14 defining the air chamber 20 and the fourth seal ring 14 disposed further on the front side. The second lubricating chamber 22 is filled with a lubricating liquid 25 having sufficient fluidity by a liquid supply means 37 described later.
The sealing device 1 of the present embodiment copes with fluctuations in the draft pressure P in a state higher than the first air supply means 26 for supplying pressurized air into the air chamber 20 and the air pressure P1 in the air chamber 20. And second air supply means 27 for supplying pressurized air that changes in the pod 4.
[0024]
Among these, the first air supply means 26 includes a first compressed air source 28 made of a compressor or the like disposed in the hull 3 and a rear side of the pair of seal rings 13 and 14 that define the air chamber 20. An air control unit 29 that sets the pressure of the pressurized air from the first compressed air source 26 to such an extent that air is blown out from the second seal ring 13, and the compressed air that has passed through the air control unit 29 is air The air pipe 30 is led to the chamber 20.
The air control unit 29 includes a pressure reducing valve 31 and a flow rate adjusting valve 32 connected to the downstream side thereof. In the present embodiment, the first compressed air source 28 has an air pressure of 7 to 8 (kg / cm ² ) Is used, and this air pressure is reduced by 2-3 (kg / cm) by the pressure reducing valve 31. ² ) Depressurized to a certain extent. Further, the flow rate of the pressurized air is set to about 10 to 40 (Nl / min) by the flow rate adjusting valve 32, and the pressurized air is fed into the air chamber 20 at a constant flow rate. The pressurized air is always blown out from the outside.
[0025]
The tightening force of the garter spring 23 of the seal ring 13 is approximately 0.1 (kg / cm ² ), The draft pressure at the center position of the propeller shaft 7 by the external water W is P (kg / cm ² ), The air pressure P1 in the air chamber 20 is P + 0.1 (kg / cm) due to the above-mentioned blowout of pressurized air. ² And is controlled to a pressure that is always higher than the draft pressure P by a certain differential pressure and that corresponds to the fluctuation of the draft pressure P.
On the other hand, the second air supply means 27 is supplied from the second compressed air source 34 made of a compressor or the like disposed in the hull 3 and the second compressed air source 34 using the air pressure in the air pipe 30 as a pilot pressure. An air relay 35 that sets the pressurized air to a predetermined output pressure, and a pressure pipe 36 that applies the output pressure set by the air relay 35 to the pod 4 are provided.
[0026]
Therefore, by setting the output pressure of the air relay 35 to be higher than the air pressure P1 in the air chamber 20, pressurization that changes in response to the fluctuation of the draft pressure P in a state higher than the air pressure P1 in the air chamber 20. Air can be supplied into the pod 4.
In the present embodiment, the output pressure of the air relay 35 is 0.2 (kg / cm) with respect to the pilot pressure. ² ) So that the inside of the pod 4 is P1 + 0.2 (kg / cm ² ) = P + 0.3 (kg / cm ² ), That is, 0.3 (kg / cm) always with respect to the draft pressure P ² ) Can only be kept high.
[0027]
Further, the sealing device 1 of the present embodiment includes a liquid supply means 37 including an oil pump for supplying the lubricating liquid 25 into the second lubrication chamber 22 and lubrication that has leaked into the air chamber 20 due to the supply. And a drain circuit 38 connected to the air chamber 20 for collecting the liquid 25 and the external water W in the ship. The drain circuit 38 includes a discharge pipe 39 connected to the air chamber 20 and a drain tank 40 disposed in the hull 3 or the pod 4.
[0028]
The liquid supply means 37 may be one that constantly pumps the lubricating liquid 25 little by little at a constant flow rate, or may be one that intermittently pumps the lubricating liquid 25 at regular intervals. Further, the drain tank 40 and the liquid supply means 37 can be provided inside the pod 4 if there is room in the pod 4, but it is preferable to arrange the drain tank 40 and the liquid supply means 37 in the hull 3 because the pod 4 can be made compact. .
Next, the operation of the sealing device 1 according to the above configuration will be described.
That is, in the present embodiment, the first air supply means 26 supplies pressurized air into the air chamber 20 inside the casing 5 connected to the rear side of the pod 4. The sliding load acting on the lip portion of the seal rings 13 and 14 is reduced, and the durability of the seal rings 13 and 14 is improved. In particular, in the present embodiment, since pressurized air is constantly blown from the second seal ring 13, the lip portion of the ring 13 hardly comes into sliding contact with the outer peripheral surface of the propeller shaft 7. The lifetime can be greatly increased.
[0029]
On the other hand, the second air supply means 27 supplies the pressurized air that changes in response to the fluctuation of the draft pressure P in the pod 4 in a state higher than the air pressure P1 in the air chamber 20. As described above, even if the external water W enters the air chamber 20 by reducing the sliding load acting on the lip portions of the seal rings 13 and 14, the external water W may further leak into the pod 4. Effectively prevented.
Thus, according to the sealing device 1 of the present embodiment, the first air supply means 26 effectively prevents the external water W from leaking into the pod 4 by the second air supply means 27, and the pod 4 can reduce the sliding load acting on the lip portion of the seal rings 13 and 14 by supplying pressurized air to the air chamber 20 provided on the rear side of the pod 4, so that the internal device of the pod 1 is broken. The durability of the seal rings 13 and 14 can be improved without causing corrosion.
[0030]
Further, according to the present embodiment, the liquid supply means 37 for supplying the lubricating liquid 25 is provided in the second lubricating chamber 22 and the drain circuit 38 is connected to the air chamber 20. Even if W leaks into the air chamber 20, they can be recovered in the ship. For this reason, the seal ring 14 can be made into a lubrication state, preventing the environmental contamination accompanying the lubricating liquid 25 being blown outside.
Furthermore, in this embodiment, since the lubricant 24 in the first lubrication chamber 21 has such a high viscosity that it is not blown off to the rear side, the pressure of the pressurized air is increased to the extent that air blows out from the air chamber 20. Even in this case, the lubricant 24 does not scatter to the outside, and in this respect as well, environmental pollution can be prevented in advance, and it is also necessary to add a seal ring on the rear side to prevent oil leakage. Therefore, the axial dimension of the sealing device 1 can be made compact.
[0031]
FIG. 3 shows a modification of the second circulation chamber 22.
That is, in this modification, the fourth seal ring 15 constituting the second circulation chamber 22 is arranged so that the front end edge of the lip portion faces the rear side. In this case, since the second lubrication chamber 22 is partitioned between the pair of seal rings 14 and 15 in which the leading edges of the lip portions face each other, the lubricating liquid 25 is more likely to leak to the pod 4 side. It can be effectively prevented.
However, in the case of such a structure, it is necessary to connect the safety valve 41 to the second lubrication chamber 22 so that the inside of the second circulation chamber 22 does not become too high due to the pumping force of the liquid supply means 37. The relief pressure of the safety valve 41 is 0.2 (kg / cm) than the air pressure P2 in the pod 4. ² ) Just set a high level.
[0032]
FIG. 4 shows a second embodiment of the sealing device 1 according to the present invention.
The main difference between the first embodiment and the present embodiment is that the former is a type in which pressurized air is blown out through the seal ring, whereas the latter is the external water W without passing through the seal ring. The air pressure in the air chamber can be changed by blowing out pressurized air to the other, and other configurations are almost the same.
Therefore, in the following, points different from the first embodiment will be described with emphasis, and members having the same structure or function will be denoted by the same reference numerals in the drawings, and redundant description will be omitted.
[0033]
As shown in FIG. 4, the first air supply means 26 of the present embodiment includes a first compressed air source 43 composed of a compressor or the like disposed in the hull 3, and pressurized air from the compressed air source 43. The air pressure control unit 44 sets the air pressure to a predetermined pressure and flow rate, and the compressed air that has passed through the air control unit 44 is blown directly to the external water W without passing through the seal rings 12 and 13 to detect the draft pressure P. A detection pipe 45, a first air relay 46 that sets the pressurized air from the first compressed air source 43 to a predetermined output pressure using the air pressure in the detection pipe 45 as a pilot pressure, and the first air relay 46 And an air pipe 47 that applies the set output pressure into the air chamber 20.
[0034]
The air control unit 44 of this embodiment includes a pressure reducing valve 48, a flow rate adjusting valve 49 connected to the downstream side thereof, and the first air relay 46. In the illustrated example, the outlet of the detection pipe 45 is arranged at the base end portion of the casing 5, but this outlet can also be arranged on the pod 4 or the hull 3 side.
In the first air supply means 43, if the output pressure of the first air relay 46 is set higher than the air pressure in the detection pipe 45 by the tightening force of the garter spring 23, the same as in the case of the first embodiment. Further, the air pressure inside the air chamber 20 can be set to such an extent that the pressurized air is blown out from the air chamber 20.
[0035]
Further, according to the first air supply means 43 of the present embodiment, the output pressure of the first air relay 46 can be set to a value substantially equal to or slightly lower than the air pressure in the detection pipe 45. In this case, since the pressurized air does not blow out from the air chamber 20, it is possible to prevent the lubricating liquid 25 from leaking out of the ship with the blowout, and to reduce the air consumption as much as possible. is there.
On the other hand, the second air supply means 27 is supplied from the second compressed air source 50 composed of a compressor or the like disposed in the hull 3 and the second compressed air source 50 using the air pressure in the detection pipe 45 as a pilot pressure. A second air relay 51 that sets the pressurized air to a predetermined output pressure, and a pressure pipe 52 that applies the output pressure set by the second air relay 51 into the pod 4 are provided.
[0036]
Therefore, according to the second air supply means 27, the output pressure of the second air relay 52 is set higher than the air pressure P1 in the air chamber 20, so that the air pressure is higher than the air pressure P1 in the air chamber 20. Thus, pressurized air that changes in response to fluctuations in the draft pressure P1 can be supplied into the pod 4.
In addition, this invention is not limited to each above-described embodiment, It can change variously. For example, the first seal ring 12 may be omitted and the first lubrication chamber 21 may not be provided.
[0037]
Moreover, in the said embodiment, although the pod propeller propulsion system 2 is provided in the stern part of the hull 3, this propulsion system 2 can also be provided in the center part and the bow part of the hull 3, and the undersea oil field which floats on the sea. It can be provided in various floating structures such as drilling plants and airports.
[0038]
【The invention's effect】
As described above, according to the present invention, it is possible to supply pressurized air to the air chamber provided in the rear part of the pod while effectively preventing external water from leaking into the pod. The durability of the seal ring can be improved without failure or corrosion.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a pod propeller propulsion system according to a first embodiment.
FIG. 2 is a side sectional view of the sealing device of the first embodiment.
FIG. 3 is a cross-sectional view inside a casing for illustrating a modification of the second lubrication chamber.
FIG. 4 is a side sectional view of a sealing device according to a second embodiment.
[Explanation of symbols]
1 Sealing device
2 Pod propeller propulsion system
3 hull (floating structure)
4 Pods
5 Casing
6 Electric motor
7 Propeller shaft
12 First seal ring
13 Second seal ring
14 Third seal ring
15 Fourth seal ring
20 Air chamber
21 First circulation chamber
22 Second circulation chamber
24 Lubricant
25 Lubricating liquid
26 First air supply means
27 Second air supply means
28 First compressed air source
29 Air control unit
30 Air piping
34 Second compressed air source
35 Air Relay
36 Pressurized piping
37 Liquid supply means
38 Drain circuit
43 First compressed air source
44 Air control unit
45 Detection piping
46 First Air Relay
47 Air piping
50 Second compressed air source
51 Second air relay
52 Pressure piping

Claims (7)

A pod (4) provided on the floating structure (3) so as to be rotatable about the longitudinal axis, a cylindrical casing (5) connected to the rear side of the pod (4), and the casing (5) A propeller shaft (7) that is coaxially inserted into the pod (4) and connected to an electric motor (6), and an outer water surface that is in sliding contact with the outer peripheral surface of the shaft (7). A seal device of a pod propeller propulsion system comprising a plurality of seal rings (12, 13, 14, 15) for sealing (W),
A first air supply that supplies pressurized air into an air chamber (20) defined between a pair of adjacent seal rings (13, 14) among the plurality of seal rings (12, 13, 14, 15). Means (26);
Second air supply means for supplying pressurized air that changes in response to fluctuations in draft pressure (P) in a state higher than the air pressure (P1) in the air chamber (20) into the pod (4). 27) and
A sealing device for a pod propeller propulsion system. Of the pair of seal rings (13, 14) defining the air chamber (20), a partition is formed between the seal ring (14) on the front side and the seal ring (15) disposed on the front side. Liquid supply means (37) for supplying a lubricating liquid (25) into the lubricated chamber (22),
A drain circuit (38) connected to the air chamber (20) for recovering the lubricating liquid (25) and external water (W) leaking into the air chamber (20) into the floating structure (3). )When,
The sealing device for a pod propeller propulsion system according to claim 1, wherein: Of the pair of seal rings (13, 14) defining the air chamber (20), the seal ring is defined between the seal ring (13) on the rear side and the seal ring (12) disposed on the rear side. The lubricating chamber (21) is filled with a lubricant (24) having such a high viscosity that it is not blown off to the rear side by pressurized air blown out from the air chamber (20). 3. A sealing device for a pod propeller propulsion system according to 1 or 2. The first air supply means (26) includes a first compressed air source (28) and a seal ring on the rear side of a pair of seal rings (13, 14) that define the air chamber (20) ( 13) An air control unit (29) for setting the pressure of the compressed air from the compressed air source (28) to such an extent that air is blown to the outside, and the compressed air that has passed through the air control unit (29) The pod propeller propulsion system sealing device according to any one of claims 1 to 3, further comprising an air pipe (30) leading to the air chamber (20). The second air supply means (27) is pressurized from the second compressed air source (34) using the second compressed air source (34) and the air pressure in the air pipe (30) as a pilot pressure. An air relay (35) for setting air to a predetermined output pressure, and a pressure pipe (36) for applying the output pressure set by the air relay (35) into the pod (4). The sealing device of the pod propeller propulsion system according to claim 4. The first air supply means (26) includes a first compressed air source (43) and an air control unit (44) for setting the pressurized air from the compressed air source (43) to a predetermined pressure and flow rate. And a detection pipe (45) for detecting the draft pressure (P) by blowing the pressurized air that has passed through the air control unit (44) directly to the external water (W) without passing through the seal ring (13). The first air relay (46) for setting the pressurized air from the first compressed air source (43) to a predetermined output pressure using the air pressure in the detection pipe (45) as a pilot pressure, and the first A pod propeller according to any one of claims 1 to 3, further comprising an air pipe (47) for applying an output pressure set by an air relay (46) into the air chamber (20). Propulsion system sealing device. The second air supply means (27) is pressurized from the second compressed air source (50) using the second compressed air source (50) and the air pressure in the detection pipe (45) as a pilot pressure. A second air relay (51) for setting air to a predetermined output pressure, a pressure pipe (52) for applying the output pressure set by the second air relay (51) into the pod (4), The sealing device for a pod propeller propulsion system according to claim 6.

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