[0001] The present invention relates to a sealing device for pod propeller propulsion systems.
[0002] In recent years, a pod propeller propulsion system in which an electrical power generated
by a diesel engine in the hull is transformed into an electric signal by an electric
system, and the signal is transmitted to an electric motor in the pod rotatably mounted
on the stern of the hull by means of a wire, so that the propeller is rotated by a
propeller shaft connected to the motor (for example, "AZIPOD", a product of ABB Azipod)
has been a focus of attention. Since the pod is freely rotatable outside the hull,
this system has various advantages such that a steering apparatus is not necessary
and the steerage is improved; that inboard noise and vibration can be reduced because
it is electrically propelled; that the variation of design such as to dispose the
engine on the bow-side of the hull expands; and the like.
[0003] Even in such a pod propeller propulsion system, a sealing device is required as a
matter of course. The sealing device employed in this case comprises a pod provided
at the stern of the hull in such a manner that it is able to rotate freely about the
vertical axis, a cylindrical casing connected to the pod on the stern-side of the
hull, a propeller shaft coaxially inserted into the casing and connected to the electric
motor disposed in the pod, and a plurality of seal ring to be brought into sliding
contact with the outer periphery of the shaft to seal off outside water.
[0004] Recently, there is a problem in that increase in draft pressure in association with
upsizing of marine vessels promotes early damage of the seal ring, which may cause
outboard leakage of lubricant and accordingly results in environmental pollution.
[0005] Therefore, as a stern tube sealing device employed in a normal marine vessel propulsion
system other than the above-described pod propeller propulsion system, an air-seal
stern tube sealing device in which sliding load on the lip of the seal ring is lowered
to improve durability of the seal ring by supplying compressed air to an air chamber
defined between an adjacent pair of seal rings out of a plurality of seal rings to
constantly blow off air from the chamber toward outboard water (See Japanese Examined
Utility Model Publication No. 35249/1993, and Japanese Unexamined Patent Application
Publication No. 304005/1999), or by supplying compressed air having air pressure which
varies corresponding to variation in draft pressure and is lower than the draft pressure
by a predetermined pressure difference into the air chamber (See Japanese Patent Publication
No.2778899) is known.
[0006] In the pod propeller propulsion system of the related art, it is necessary to solve
the problem that when the draft pressure increases with upsizing of the marine vessel,
the seal ring may be damaged at an early stage and accordingly lubricant leaks outboard,
which may result in environmental pollution. Therefore, it is believed that the durability
of the seal ring is improved by adopting the above-described air-seal stern tube sealing
device employed in the normal marine vessel propulsion system to the rear portion
of the pod that constitutes the pod propeller propulsion system.
[0007] However, since an electric motor that has a weakness for water, a radial bearing
that is apt to corrode due to sea water, and the like are stored in the pod of the
pod propeller propulsion system, the pod propeller propulsion system may be fatally
damaged with mere adoption of the conventional air-seal stern tube sealing device
to the rear portion of the pod.
[0008] In other words, when the air chamber defined at the rear portion of the pod is applied
with pressure to the extent that allows a jet of air to blow off therefrom, or that
is slightly lower than the draft pressure, compressed air can easily be blown off
from the seal ring on the front-side (closer side to the pod) that constitutes the
chamber into the pod. Therefore, there may arise another problem that outside water
entered into the air chamber leaks together with compressed air into the pod, which
may increase the possibility of breakdown of the electric motor or corrosion of the
radial bearing.
[0009] In view of such circumstances, it is an object of the present invention to provide
an air-seal type sealing device for pod propeller propulsion systems, wherein compressed
air can be supplied to an air chamber provided on the rear-side of a pod while effectively
preventing leakage of outside water into the pod, so that durability of the seal ring
is increased without breakdown or corrosion of internal equipment in the pod.
[0010] In order to achieve the above-described object, the present invention devises following
technical means.
[0011] The present invention provides a sealing device for pod propeller propulsion system
according to claim 1.
[0012] According to the present invention, since the first air supplying means supplies
compressed air into the air chamber in a casing connected to the rear-side of the
pod, the sliding load on the lips of the seal rings for defining the air chamber is
reduced, thereby improving durability of the seal ring.
[0013] On the other hand, since the second air supplying means supplies compressed air having
air pressure higher than that in the air chamber and varying corresponding to variations
in draft pressure into the pod, even when outside water enters into the air chamber
because of the sliding load on the lips of the seal rings is reduced as described
above, outside water is effectively prevented from being leaked into the pod.
[0014] Therefore, according to the present invention, the sliding load acting upon the lips
of the seal rings can be reduced by supplying compressed air to the air chamber provided
on the rear-side of the pod by means of the first air supplying means while effectively
preventing outside water from leaking into the pod by means of the second air supplying
means, and thus the durability of the seal ring can be increased without breakdown
or corrosion of the internal equipment of the pod.
[0015] The preferred embodiments of the present invention will now be described according
to the contents of the dependent claims.
[0016] In the present invention, in order to ensure improvement of the lifetime of the seal
ring, it is necessary to lubricate the lip of the seal ring by lubricating material
such as grease, lubricant, or the like.
[0017] Therefore, it is recommended to construct a lubricant chamber between the seal ring
on the front-side out of a pair ot seal rings for defining the air chamber and a next
seal ring located further on the front-side and provide liquid supplying means for
supplying a liquid lubricant into the lubricant chamber.
[0018] When such a liquid supplying means is provided, since a liquid lubricant or outside
water may leak into the air camber, it is preferred to connect a drain circuit with
the air chamber for collecting them within the pod or a structure to which the pod
is mounted.
[0019] On the other hand, in order to keep the seal ring on the rear-side (farther side
from the pod) out of a pair of seal ring for defining the air chamber lubricated,
it is preferred that a lubricant chamber defined between the seal ring and a seal
ring located further on the rear-side is filled with lubricant highly viscous to the
extent that it cannot be blown off outside the casing even by compressed air injected
from the air chamber.
[0020] In this case, since lubricant in the lubricant chamber positioned on the rear-side
of the air chamber has a high viscosity to the extent that it cannot be blown off
outside the casing, even when the pressure of compressed air is increased to the extent
that air is blown out from the air chamber, the lubricant is prevented from being
scattered out of the casing and thus environmental pollution can be prevented in advance.
When lubricant filled in the lubricant chamber is highly viscous as described above,
it is not necessary to add another seal ring on the rear-side for preventing oil leakage,
whereby the axial dimension of the sealing device may be reduced.
[0021] In the present invention, when employing the sealing device of the type that blows
off compressed air through the seal ring, the first air supplying means comprising
a first compressed air source, an air control unit for setting the pressure of compressed
air from the compressed air source to the extent that air is blown off outside of
the casing from the seal ring on the rear-side out of a pair of seal rings that define
the air chamber, and an air piping for conducting the compressed air passed through
the air control unit to the air chamber may be employed.
[0022] In this case, since air is regularly blown off from the air chamber, by employing
a second air supplying means comprising a second compressed air source, an air relay
for setting the air pressure of the compressed air from the second compressed air
source to a predetermined output pressure with the air pressure in the air piping
as a pilot pressure, and a pressurizing piping for applying the output pressure set
at the air relay to the interior of the pod, and by setting the output pressure of
the air relay slightly higher than the air pressure in the air chamber, compressed
air having air pressure higher than that in the air chamber and varying corresponding
to variations in draft pressure can be supplied into the pod.
[0023] In the present invention, when employing the sealing device of the type that the
air pressure in the air chamber can be varied, the first air supplying means comprising
a first compressed air source, an air control unit for setting pressure of compressed
air from the compressed air source to a predetermined pressure and flow rate, a detecting
piping for blowing off the compressed air passed through the air control unit directly
to outside water without passing through the seal ring to detect the draft pressure,
a first air relay for setting pressure of compressed air from the first compressed
air source to predetermined output pressure corresponding to the air pressure in the
detecting piping as a pilot pressure, and an air piping for applying the output pressure
predetermined at the first air relay into the air chamber may be employed.
[0024] In this case, by setting the output pressure of the first air relay to a value higher
than the air pressure in the detecting piping by the pressure corresponding to a tightening
force of the garter spring, the air pressure of the air chamber can be set to the
extent that air is blown off therefrom. On the other hand, when the output pressure
of the first air relay is set to almost the same value as the air pressure in the
detecting piping or slightly lower than that value, compressed air is not blown off
from the air chamber and, hence, outboard leakage of the liquid lubricant out of the
casing in association with its blowoff may be prevented in advance, and advantageously,
the amount of air consumption may be reduced as low as possible.
[0025] In this case, since it is possible to carry out control in which air is not always
blown off from the air chamber, compressed air having air pressure higher than that
in the air chamber and varying corresponding to variations in draft pressure can be
supplied into the pod by employing the second air supplying means comprising a second
compressed air source, a second air relay for setting pressure of compressed air from
the second compressed air source to a predetermined output pressure corresponding
to the air pressure in the detecting piping as a pilot pressure, and a pressurized
piping for applying the output pressure set at the second air relay into the pod,
and by setting the output pressure of the second air relay slightly higher than the
air pressure in the air chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026]
Fig. 1 is a schematic side view of the pod propeller propulsion system according to
the first embodiment;
Fig. 2 is a cross sectional side view of the sealing device according to the first
embodiment;
Fig. 3 is a cross sectional view in the casing for illustrating a modification of
the second lubricant chamber; and
Fig. 4 is a cross sectional side view of the sealing device according to the second
embodiment.
[0027] Referring now to the drawings, the embodiment of the present invention will be described.
[0028] Figs. 1 to 3 show a first embodiment of a sealing device 1 according to the present
invention.
[0029] As shown in Fig. 1, the sealing device 1 of this embodiment is designed for a pod
propeller propulsion system 2. The propulsion system 2 comprises a pod 4 provided
at a stern of a hull 3 as an example of a structure floating on the water so as to
rotate freely about a vertical axis, a cylindrical casing 5 connected to the rear-side
of the pod 4, and a propeller shaft 7 inserted coaxially into the casing 5 and connected
to an electric motor 6 disposed in the pod 4.
[0030] The end of the shaft 7 on the front-side (right end in Fig. 1) is supported by a
thrust bearing 8 disposed at the front portion of the pod 4 so as to rotate freely
but not to move in the axial direction, and the end of the shaft 7 on the rear-side
(left end in Fig. 1) is supported by a radial bearing 9 disposed at the rear end of
the pod 4 so as to rotate freely. The end of the shaft 7 on the rear-side projects
outside the pod 4, and a propeller 10 is fixed on the projected end.
[0031] The sealing device 1 of this embodiment is an external sealing device disposed outside
the pod 4 on the rear-side thereof, while between the radial bearing 9 and the motor
6 in the pod 4 an internal sealing device 11 is provided.
[0032] As shown in Fig. 2, the sealing device 1 described above comprises the pod 4 provided
at the stern of the hull 3 so as to rotate freely about the vertical axis, the cylindrical
casing 5 connected to the rear-side of the pod 4, the propeller shaft 7 inserted coaxially
into the casing 5 and connected to the electric motor 6 disposed in the pod 4, and
a plurality of seal rings 12-15 in sliding contact with the outer periphery of the
shaft 7 for sealing outside water W.
[0033] The propeller shaft 7 comprises a shaft body 16 connected directly to the motor 6,
and a cylindrical liner 17 mounted on the axial portion of the shaft body 16 corresponding
to the casing 5, wherein the lip of each seal ring 12-15 having a proximal end fixed
on the inner peripheral surface of the casing 5 is in sliding contact with the outer
peripheral surface of the liner 17.
[0034] The shaft 7 may be constructed only of the shaft body 16, without providing the liner
17.
[0035] In this embodiment, there are provided four seal rings 12-15 in total for defining
an air chamber 20 within the casing 5 and lubricant chambers 21, 22 on the rear side
and front side thereof.
[0036] The first seal ring 12 disposed at the rearmost position (left side in Fig. 2) and
the second seal ring 13 disposed next to the first ring on the front-side are oriented
in such a manner that the tip edges of the lips face toward the rear-side. The third
seal ring 14 that is disposed at the third rearmost position and the fourth seal ring
15 disposed next to the third seal ring 14 on the front-side are oriented in such
a manner that the tip edges of the lips thereof face toward the front-side (right
side in Fig. 2). The lips of the seal rings 12-15 are all wound with ring-shaped garter
springs 23 respectively.
[0037] The chamber defined between the second seal ring 13 and the third seal ring 14 is
used as an air chamber 20 the inside of which is pressurized by compressed air, and
a chamber defined between the second seal ring 13 which is the rear-side one of a
pair of seal rings 13, 14 defining the air chamber 20 and the first seal ring 12 that
is disposed further on the rear-side thereof is used as the first lubricant chamber
21 which is to be filled with a high viscosity lubricant 24.
[0038] In other words, the first lubricant chamber 21 is filled with the lubricant 24 formed
of grease or the like that is highly viscous to the extent that it cannot be blown
off outside the casing even by compressed air blown off from the air chamber 20.
[0039] A chamber defined between the third seal ring 14 which is the front-side one of a
pair of seal rings 13, 14 defining the air chamber 20 and the fourth seal ring 14
disposed further on the front-side thereof is used as the second lubricant chamber
22 which is filled with a liquid lubricant 25 having sufficient fluidity by liquid
supplying means 37 described later.
[0040] The sealing device 1 of this embodiment comprises a first air supplying means 26
for supplying compressed air into the air chamber 20, and a second air supplying means
27 for supplying compressed air having air pressure higher than the air pressure P1
in the air chamber 20 and varying corresponding to variations in draft pressure P
into the pod 4.
[0041] The first air supplying means 26 comprises a first compressed air source 28 including
a compressor and the like disposed in the hull 3, an air control unit 29 for setting
pressure of compressed air from the first compressed air source 28 to the extent that
air is blown off outside the casing from the second seal ring 13 on the rear-side
out of a pair of seal rings 13, 14 defining the air chamber 20, and an air piping
30 introducing compressed air passed through the air control unit 29 to the air chamber
20.
[0042] The air control unit 29 is provided with a pressure reducing valve 31 and a flow
regulating valve 32 connected at a downstream side thereof. In this embodiment, the
first compressed air source 28 supplying compressed air of 7-8 (kg/cm
2) is used and then the air pressure is reduced by the pressure reducing valve 31 to
about 2-3 (kg/cm
2). Concurrently, the flow rate of compressed air is set to approximately 10-40 (Nl/min.)
by the flow regulating valve 32 to supply compressed air at a constant flow rate to
the air chamber 20, so that compressed air is regularly blown off outside the casing
from the lip of the second seal ring 13.
[0043] Since the tightening force of the garter spring 23 of the seal ring 13 is generally
0.1 (kg/cm
2), the air pressure P1 in the air chamber 20 is set to P+0.1 (kg/cm
2) by the blowoff of compressed air described above, where the draft pressure at the
center of the propeller shaft 7 of outside water W is P (kg/cm
2), and thus the air pressure P1 is controlled to vary corresponding to variations
of the draft pressure P with regularly keeping a level higher than the draft pressure
P by a constant pressure difference.
[0044] On the other hand, the second air supplying means 27 comprises a second compressed
air source 34 including a compressor and the like disposed in the hull 3, an air relay
35 for setting pressure of compressed air from the second compressed air source 34
to a predetermined output pressure with the air pressure in the air piping 30 as a
pilot pressure, and a pressurizing piping 36 for applying the output pressure set
at the air relay 35 to the interior of the pod 4.
[0045] Therefore, by setting the output pressure of the air relay 35 slightly higher than
the air pressure P1 in the air chamber 20, compressed air having air pressure higher
than the air pressure P1 in the air chamber 20 and varying corresponding to variations
in draft pressure P can be supplied into the pod 4.
[0046] In this embodiment, the output pressure of the air relay 35 is set to a value 0.2
(kg/cm
2) higher than the pilot pressure, and thus the pressure in the pod 4 can be maintained
at P1+0.2(kg/cm
2)=P+0.3(kg/cm
2), in other words, at a pressure constantly 0.3(kg/cm
2) higher than the draft pressure P.
[0047] The sealing device 1 of this embodiment comprises the liquid supplying means 37 including
an oil pump and the like for supplying the liquid lubricant 25 into the second lubricant
chamber 22, and a drain circuit 38 connected to the air chamber 20 for collecting
the liquid lubricant 25 leaked into the air chamber 20 during the supply thereof or
outside water W within the pod 4 or the hull 3. The drain circuit 38 is constructed
of a discharge pipeline 39 connected to the air chamber 20, and a drain tank 40 disposed
in the hull 3 or the pod 4.
[0048] The liquid supplying means 37 may be constructed to pump the liquid lubricant 25
little by little at a constant flow rate, or to pump the liquid lubricant 25 intermittently
at constant intervals. Though the drain tank 40 and the liquid supplying means 37
may be disposed in the pod 4 if it has any room for them, it is preferable to dispose
them in the hull 3 so that the pod 4 can be miniaturized.
[0049] The operation of the sealing device 1 in the above-described construction will now
be described.
[0050] In this embodiment, since the first air supplying means 26 supplies compressed air
into the air chamber 20 in the casing 5 that is connected to the rear side of the
pod 4, the sliding load on the lips of the respective seal rings 13, 14 defining the
air chamber 20 is reduced, thereby improving durability of the seal rings 13, 14.
Especially, in this embodiment, since compressed air is regularly blown off from the
second seal ring 13, the lip of the ring 13 is hardly brought into sliding contact
with the outer peripheral surface of the propeller shaft 7, thereby significantly
increasing the lifetime of the second seal ring 13.
[0051] On the other hand, since the second air supplying means 27 is constructed to supply
compressed air having air pressure higher than the air pressure P1 in the air chamber
20 and varying corresponding to variations in draft pressure P in the pod 4, even
when outside water W enters into the air chamber 20 by reducing the sliding load on
the lips of the seal rings 13, 14 as described above, further leakage of outside water
W into the pod 4 is effectively prevented.
[0052] As is described thus far, according to the sealing device 1 of this embodiment, the
sliding load on the lips of the seal rings 13, 14 may be reduced by supplying compressed
air into the air chamber 20 disposed on the rear side of the pod 4 by the first air
supplying means 26 while effectively preventing leakage of outside water W into the
pod 4 by means of the second air supplying means 27. Therefore, durability of the
seal rings 13, 14 may be improved without inducing breakdown or corrosion of the internal
equipment of the pod 4.
[0053] According to this embodiment, since the liquid supplying means 37 for supplying the
liquid lubricant 25 into the second lubricant chamber 22 is provided and the drain
circuit 38 is connected to the air chamber 20, even when the liquid lubricant 25 or
outside water W leaks into the air chamber 20, they can be collected within the hull.
Therefore, the seal ring 14 may be maintained in a lubricated state while preventing
environmental pollution in association with the blowoff of the liquid lubricant 25
outside the casing.
[0054] In addition, in this embodiment, since the lubricant 24 in the first lubricant chamber
21 is highly viscous to the extent that it cannot be blown off outside the casing,
the lubricant 24 is prevented from being scattered outside the casing even when the
pressure of compressed air is increased to the extent that air is blown off from the
air chamber 20, and thus environmental pollution may be prevented in advance. In addition,
the axial dimension of the sealing device 1 may be reduced since it is not necessary
to provide an additional seal ring on the rear-side for preventing oil leakage.
[0055] Fig. 3 shows a modification of the second lubricant chamber 22.
[0056] In this modification, the fourth seal ring 15 constituting the second lubricant chamber
22 is disposed in such a manner that the tip edge of the lip thereof faces toward
the rear-side. In this case, since the second lubricant chamber 22 is defined between
a pair of seal rings 14 and 15 the tip edges of the lips of which face with each other,
leakage of the liquid lubricant 25 into the pod 4 may be prevented more effectively.
[0057] As a matter of course, in this construction, it is necessary to provide a safety
valve 41 on the second lubricant chamber 22 to prevent the internal pressure of the
second lubricant chamber 22 from increasing too much due to a pressure force of the
liquid supplying means 37. In this case, the relief pressure of the safety valve 41
should be set to a level approximately 0.2 (kg/cm
2) higher than the air pressure P2 in the pod 4.
[0058] Fig. 4 is a second embodiment of the sealing device 1 according to the present invention.
[0059] The major difference between the first embodiment and the second embodiment is that
the first embodiment is constructed to blow off compressed air through the seal ring,
while the second embodiment is constructed in such a manner that the air pressure
in the air chamber can be varied by blowing off compressed air toward outside water
without passing through the seal ring. Other structures are almost the same.
[0060] Therefore, only the points that differ from the first embodiment are focused here,
and the members of the same construction or the same operation are designated by the
same reference numerals and not described here again.
[0061] As shown in Fig. 4, the first air supplying means 26 of this embodiment comprises
a first compressed air source 43 including a compressor and the like disposed in the
hull 3, and an air control unit 44 for setting pressure of compressed air from the
compressed air source 43 to a predetermined pressure and a flow rate, a detecting
piping 45 for blowing off compressed air passed through the air control unit 44 directly
toward outside water W without passing through the seal rings 12, 13 to detect the
draft pressure P, a first air relay 46 for setting pressure of compressed air from
the first compressed air source 43 to a predetermined output pressure with the air
pressure in the detecting piping 45 as a pilot pressure, and an air piping 47 for
applying the output pressure predetermined at the first air relay 46 into the air
chamber 20.
[0062] The air control unit 44 of this embodiment comprises a pressure reducing valve 48,
a flow regulating valve 49 connected at the downstream side thereof, and the first
air relay 46. While the discharge port of the detecting piping 45 is disposed at the
proximal portion of the casing 5 in the figure, the discharge port may be disposed
on the pod 4 or the hull 3.
[0063] In the first air supplying means 43 described above, by setting the output pressure
of the first air relay 46 to a value higher than the air pressure in the detecting
piping 45 by a pressure corresponding to a tightening force of the garter spring 23,
the air pressure of the air chamber 20 can be set to the extent that compressed air
is blown off therefrom as in the case of the first embodiment.
[0064] According to the first air supplying means 43 of this embodiment, the output pressure
of the first air relay 46 may be set to almost the same value as the air pressure
in the detecting piping 45 or slightly lower than that value. In this case, since
compressed air is not blown off from the air chamber 20, leakage of the liquid lubricant
25 out of the casing in association with its blowoff may be prevented in advance,
and advantageously, the amount of air consumption may be reduced as low as possible.
[0065] On the other hand, the second air supplying means 27 comprises a second compressed
air source 50 including a compressor and the like disposed in the hull 3, a second
air relay 51 for setting pressure of compressed air from the second compressed air
source 50 to a predetermined output pressure with the air pressure in the detecting
piping 45 as a pilot pressure, and a pressurized piping 52 for applying the output
pressure set at the second air relay 51 into the pod 4.
[0066] Therefore, according to the second air supplying means 27, by setting the output
pressure of the second air relay 52 to a value slightly higher than the air pressure
P1 in the air chamber 20, compressed air having air pressure higher than the air pressure
P1 in the air chamber 20 and varying corresponding to variations in the draft pressure
P may be supplied into the pod 4.
[0067] The present invention is not limited to the respective embodiments described above,
and various modifications are possible. For example, the construction in which the
first seal ring 12 is omitted and thus the first lubricant chamber 21 is not provided
is also applicable.
[0068] It should be noted that the pod propeller propulsion system 2 provided on the stern
portion of the hull 3 as described above may be provided also on the bow portion or
central portion of the full 3, or various structures floating on the water including
an excavation plant of offshore oil fields, floating aerodromes, and the like.
[0069] As is described thus far, according to the present invention, since compressed air
can be supplied to the air chamber provided at the rear portion of the pod while effectively
preventing outside water from being leaked into the pod, durability of the seal ring
may be improved without inducing breakdown or corrosion of the internal equipment
of the pod.
[0070] The present invention relates to a sealing device, which can be utilized to seal
around the shaft of the pod propeller propulsion system provided at the rear portion
of the hull so as to rotate freely about the vertical axis.
1. A sealing device for use as a seal between a propeller shaft (7) and a pod (4) of
a pod propeller propulsion system, comprising:
a plurality of seal rings (12, 13, 14, 15) in sliding contact with an outer periphery
of the shaft (7);
characterized by
first air supplying means (26) for supplying compressed air into an air chamber
(20) defined between a pair of adjacent seal rings (13, 14) out of the plurality of
seal rings (12, 13, 14, 15); and
second air supplying means (27) for supplying compressed air having air pressure
higher than air pressure (P1) in the air chamber (20) and varying corresponding to
variations in draft pressure (P) into the pod (4).
2. A sealing device for pod propeller propulsion system as set forth in Claim 1, further
comprising;
liquid supplying means (37) for supplying a liquid lubricant (25) into a lubricant
chamber (22) defined between the front-side seal ring (14) out of the pair of seal
rings (13, 14) for defining the air chamber (20) and the seal ring (15) that is disposed
further on the front side; and
a drain circuit (38) connected to the air chamber (20) for collecting the liquid
lubricant (25) or outside water (W) leaked into the air chamber (20) within the structure
(3).
3. A sealing device for pod propeller propulsion system as set forth in Claim 1 or Claim
2, wherein a lubricant (24) having a high viscosity to the extent that it cannot be
blown off outside the casing (5) even by compressed air blown off from the air chamber
(20) is filled in the lubricant chamber (21) defined between the rear-side seal ring
(13) out of the pair of seal rings (13, 14) defining the air chamber (20) and the
seal ring (12) disposed further on the rear side.
4. A sealing device for pod propeller propulsion system as set forth in any one of Claims
1 to 3, wherein the first air supplying means (26) comprises:
a first compressed air source (28);
an air control unit (29) for setting the pressure of compressed air from the compressed
air source (28) to the extent that air is blown off outside the casing (5) from the
rear-side seal ring (13) out of the pair of seal rings (13, 14) defining the air chamber
(20); and
an air piping (30) for introducing the compressed air passed through the air control
unit (29) into the air chamber (20).
5. A sealing device for pod propeller propulsion system as set forth in Claim 4, said
second air supplying means (27) comprises:
a second compressed air source (34);
an air relay (35) for setting pressure of compressed air from the second compressed
air source (34) to a predetermined output pressure with the air pressure in the air
piping (30) as a pilot pressure; and
a pressurizing piping (36) for applying the output pressure set at the air relay (35)
to the interior of the pod (4).
6. A sealing device for pod propeller propulsion system as set forth in any one of Claim
1 to 3, wherein the first air supplying means (26) comprising:
a first compressed air source (43);
an air control unit (44) for setting pressure of compressed air from the compressed
air source (43) to a predetermined pressure and flow rate;
a detecting piping (45) for blowing off the compressed air passed through the air
control unit (44) directly to outside water (W) without passing through the seal ring
(13) to detect the draft pressure (P);
a first air relay (46) for setting pressure of compressed air from the first compressed
air source (43) to a predetermined output pressure with the air pressure in the detecting
piping (45) as a pilot pressure; and
an air piping (47) for applying the output pressure predetermined at the first air
relay (46) into the air chamber (20).
7. A sealing device for pod propeller propulsion system as set forth in Claim 6, wherein
said second air supplying means (27) comprises:
a second compressed air source (50);
a second air relay (51) for setting pressure of compressed air from the second compressed
air source (50) to a predetermined output pressure with the air pressure in the detecting
piping (45) as a pilot pressure; and
a pressurizing piping (52) for applying the output pressure set at the second air
relay (51) into the pod (4).
1. Dichtungsvorrichtung zum Gebrauch als eine Dichtung zwischen einer Schraubenwelle
(7) und einer Gondel (4) eines Pod-Antriebssystems mit:
einer Vielzahl von Dichtungsringen (12, 13, 14, 15), die mit dem Außenumfang der Welle
(7) in Gleitkontakt sind;
gekennzeichnet durch
eine erste Zuführeinrichtung (26) zum Zuführen von Druckluft in eine zwischen einem
Paar benachbarter Dichtungsringe (13, 14) aus der Vielzahl der Dichtungsringe (12,
13, 14, 15) definierte Luftkammer (20); und
eine zweite Luftzuführeinrichtung (27) zum Zuführen von Druckluft mit einem Luftdruck,
der höher als ein Luftdruck (P1) in der Luftkammer (20) ist und sich gemäß Änderungen
im Tiefgangdruck (P) in der Gondel (4) ändert.
2. Dichtungsvorrichtung für ein Pod-Antriebssystem gemäß Anspruch 1, ferner mit:
einer Flüssigkeitszuführeinrichtung (37) zum Zuführen eines flüssigen Schmiermittels
(25) in eine Schmiermittelkammer (22), die zwischen dem vorderseitigen Dichtungsring
(14) aus dem Paar der Dichtungsringe (13, 14) zum Definieren der Luftkammer (20) und
dem Dichtungsrings (15) definiert ist, der weiter an der Vorderseite angeordnet ist;
und
einem Ableitkreislauf (38), der mit der Luftkammer (20) verbunden ist, zum Sammeln
des flüssiges Schmiermittels (25) oder Außenwassers (W), welches in die Luftkammer
(20) innerhalb der Struktur (3) leckt.
3. Dichtungsvorrichtung für ein Pod-Antriebssystem gemäß Anspruch 1 oder 2, wobei ein
Schmiermittel (24), das eine hohe Viskosität bis zu dem Ausmaß hat, dass es nicht
aus dem Gehäuse (5) herausgeblasen werden kann, selbst nicht durch von der Luftkammer
(20) herausgeblasene Druckluft, in die Schmiermittelkammer (21) gefüllt ist, die zwischen
dem rückseitigen Dichtungsring (13) aus dem Paar Dichtungsringen (13, 14), die die
Luftkammer (20) definieren, und dem weiter an der Rückseite angeordneten Dichtungsring
(12) definiert ist.
4. Dichtungsvorrichtung für ein Pod-Antriebssystem gemäß einem der Ansprüche 1 bis 3,
wobei die erste Luftzuführeinrichtung (26) folgendes aufweist:
eine erste Druckluftquelle (28);
eine Luftsteuereinheit (29) zum Einstellen des Drucks der Druckluft von der Druckluftquelle
(28) auf das Ausmaß, dass Luft von dem rückseitigen Dichtungsring (13) aus dem Paar
die Luftkammer (20) definierenden Dichtungsringen (13, 14) nach außen des Gehäuses
(5) herausgeblasen wird; und
eine Luftrohrleitung (30) zum Einführen der die Luftsteuereinheit (29) passierenden
Druckluft in die Luftkammer (20).
5. Dichtungsvorrichtung für ein Pod-Antriebssystem gemäß Anspruch 4, wobei die zweite
Luftzuführeinrichtung (27) folgendes aufweist:
eine zweite Druckluftquelle (34);
ein Luftrelais (35) zum Einstellen des Drucks der Druckluft von der zweiten Druckluftquelle
(34) auf einen vorbestimmten Ausgabedruck, wobei der Luftdruck in der Luftrohrleitung
(30) ein Vorsteuerdruck ist; und
eine Druckbeaufschlagungsrohrleitung (36) zum Aufbringen des bei dem Luftrelais (35)
eingestellten Ausgabedrucks auf das Innere der Gondel (4).
6. Dichtungsvorrichtung für ein Pod-Antriebssystem gemäß einem der Ansprüche 1 bis 3,
wobei die erste Luftzuführeinrichtung (26) folgendes aufweist:
eine erste Druckluftquelle (43);
eine Luftsteuereinheit (44) zum Einstellen des Drucks der Druckluft von der Druckluftquelle
(43) auf einen vorbestimmten Druck und Durchflussrate;
eine Erfassungsrohrleitung (45) zum Ausblasen der die Luftsteuereinheit (44) passierenden
Druckluft unmittelbar zum Außenwasser (W), ohne dabei den Dichtungsring (13) zu passieren,
um den Tiefgangdruck (P) zu erfassen;
ein erstes Luftrelais (46) zum Einstellen des Drucks der Druckluft von der ersten
Druckluftquelle (43) auf einen vorbestimmten Ausgabedruck, wobei der Luftdruck in
der Erfassungsrohrleitung (45) ein Vorsteuerdruck ist; und
eine Luftrohrleitung (47) zum Aufbringen des an dem ersten Luftrelais (46) vorbestimmten
Ausgabedrucks in die Luftkammer (20).
7. Dichtungsvorrichtung für ein Pod-Antriebssystem gemäß Anspruch 6, wobei die zweite
Luftzuführeinrichtung (27) folgendes aufweist:
eine zweite Druckluftquelle (50);
ein zweites Luftrelais (51) zum Einstellen des Drucks der Druckluft von der zweiten
Druckluftkammer (50) auf einen vorbestimmten Ausgabedruck, wobei der Luftdruck in
der Erfassungsrohrleitung (45) ein Steuerdruck ist; und
eine Druckbeaufschlagungsrohrleitung (52) zum Aufbringen des an dem zweiten Luftrelais
(51) eingestellten Ausgabedrucks in die Gondel (4).
1. Dispositif d'étanchéité destiné à être utilisé sous forme de joint entre un arbre
d'hélice (7) et une nacelle (4) d'un système de propulsion à hélice en nacelle, comprenant
:
une pluralité de bagues d'étanchéité (12, 13, 14, 15) en contact coulissant avec une
périphérie extérieure de l'arbre (7) ;
caractérisé par
des premiers moyens d'alimentation en air (26) permettant de fournir de l'air comprimé
dans une chambre à air (20) définie entre une paire de bagues d'étanchéité adjacentes
(13, 14) parmi la pluralité de bagues d'étanchéité (12, 13, 14, 15) ; et
de seconds moyens d'alimentation en air (27) permettant de fournir de l'air comprimé
présentant une pression d'air supérieure à la pression de l'air comprimé (P1) dans
la chambre à air (20) et variant en fonction des variations de la pression de tirage
(P) vers l'intérieur de la nacelle (4).
2. Dispositif d'étanchéité destiné à un système de propulsion à hélice en nacelle selon
la revendication 1, comprenant en outre :
des moyens de fourniture de liquide ((37) permettant de fournir un lubrifiant liquide
(25) dans la chambre de lubrifiant (22) définie, entre la bague d'étanchéité (14)
côté avant parmi une paire de bagues d'étanchéité (13, 14) destinées à définir la
chambre à air (20), et la bague d'étanchéité (15) qui est disposée plus loin sur le
côté avant ; et
un circuit de drainage (38) relié à la chambre à air (20) permettant de collecter
le lubrifiant liquide (25) ou l'eau extérieure (W) ayant coulé dans le chambre à air
(20) à l'intérieur de la structure (3).
3. Dispositif d'étanchéité destiné à un système de propulsion à hélice en nacelle selon
la revendication 1 ou 2, dans lequel un lubrifiant (24), présentant une viscosité
élevée au point où il ne peut pas être emporté en dehors du carter (5) même par l'intermédiaire
de l'air comprimé soufflé provenant de la chambre à air (20), est empli dans la chambre
de lubrificant (21) définie, entre la bague d'étanchéité (13) côté arrière, parmi
la partie de bagues d'étanchéité (13, 14) définissant la chambre à air (20), et la
bague d'étanchéité (12) disposée plus loin sur le côté arrière.
4. Dispositif d'étanchéité destiné à un système de propulsion à hélice en nacelle selon
l'une quelconque des revendications 1 à 3, dans lequel les premiers moyens d'alimentation
en air (26) comprennent :
une première source d'air comprimé (28) ;
une unité de régulation d'air (29) permettant de régler la pression de l'air comprimé
provenant de la source d'air comprimé (28), dans la mesure où l'air est soufflé en
dehors du carter (5) depuis la bague d'étanchéité (13) parmi les bagues d'étanchéité
(13, 14) définissant la chambre à air (20) ; et
une conduite d'air (30) permettant d'introduire dans la chambre à air (20) l'air comprimé
ayant traversé l'unité de régulation d'air (29).
5. Dispositif d'étanchéité destiné à un système de propulsion à hélice en nacelle selon
la revendication 4, lesdits seconds moyens d'alimentation en air (27) comprenant :
une seconde source d'air comprimé (34) ;
un relais d'air (35) permettant de régler la pression de l'air comprimé provenant
de la seconde source d'air comprimé (34) à une pression de sortie prédéterminée avec
la pression d'air contenue dans la conduite d'air (30) en tant que pression pilote
; et
une conduite de mise sous pression (36) permettant d'appliquer la pression de sortie
réglée au niveau du relais d'air (35) à l'intérieur de la nacelle (4).
6. Dispositif d'étanchéité destiné à un système de propulsion à hélice en nacelle selon
l'une quelconque des revendications 1 à 3, dans lequel les premiers moyens d'alimentation
en air (26) comprennent :
une première source d'air comprimé (43) ;
une unité de régulation d'air (44) permettant de régler la pression de l'air comprimé
provenant de la source d'air comprimé (43) à une pression et une vitesse d'écoulement
prédéterminés ;
une conduite de détection (45) permettant de souffler l'air comprimé ayant traversé
l'unité de régulation d'air (44) directement vers l'eau extérieure (W) sans passer
à travers la bague d'étanchéité (13) pour détecter la pression de tirage (P) ;
un premier relais d'air (46) permettant de régler la pression de l'air comprimé provenant
de la première source d'air comprimé (43) à une pression de sortie prédéterminée avec
la pression d'air contenue dans la conduite de détection (45) en tant que pression
pilote ; et
une conduite d'air (47) permettant d'appliquer la pression de sortie prédéterminée
au niveau du premier relais d'air (46) à l'intérieur de la chambre à air (20).
7. Dispositif d'étanchéité destiné à un système de propulsion à hélice en nacelle selon
la revendication 6, dans lequel lesdits seconds moyens d'alimentation en air (27)
comprennent :
une seconde source d'air comprimé (50) ;
un second relais d'air (51) permettant de régler l'air comprimé provenant d'une seconde
source d'air comprimé (50) à une pression de sortie prédéterminée avec la pression
d'air contenue dans la conduite de détection (45) en tant que pression pilote ; et
une conduite de mise sous pression (52) permettant d'appliquer la pression de sortie
réglée au niveau du second relais d'air (51) à l'intérieur de la nacelle (4).