U.S. patent application number 10/489970 was filed with the patent office on 2005-06-09 for device for sealing a passage through a wall.
Invention is credited to Andersson, Per-Olof.
Application Number | 20050121857 10/489970 |
Document ID | / |
Family ID | 20285393 |
Filed Date | 2005-06-09 |
United States Patent
Application |
20050121857 |
Kind Code |
A1 |
Andersson, Per-Olof |
June 9, 2005 |
Device for sealing a passage through a wall
Abstract
The invention refers to a device for sealing a passage (1)
through a stationary wall (2) between a first space (3), which is
arranged to contain a liquid. A rotatable shaft (5) is intended to
extend in the passage through the wall in such a way that a gap is
formed, which extends around the shaft between the shaft and the
wall. A chamber (8), containing liquid, is arranged between the gap
and the first space and extends around the axis. A rotatable disc
(14) is fixedly arranged on the shaft and exends outwardly from the
shaft into said chamber. Means (17', 17") are arranged to force the
liquid in the chamber to rotate at a rotary speed substantially
exceeding the rotary speed of the shaft.
Inventors: |
Andersson, Per-Olof;
(Vasterhaninge, SE) |
Correspondence
Address: |
Swidler Berlin
Shereff Friedman
Suite 300
3000 K Street NW
Washington
DC
20007
US
|
Family ID: |
20285393 |
Appl. No.: |
10/489970 |
Filed: |
January 14, 2005 |
PCT Filed: |
September 20, 2002 |
PCT NO: |
PCT/SE02/01708 |
Current U.S.
Class: |
277/431 |
Current CPC
Class: |
F16J 15/406 20130101;
F16J 15/42 20130101 |
Class at
Publication: |
277/431 |
International
Class: |
F01D 011/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2001 |
SE |
0103136-8 |
Claims
1-24. (canceled)
25. A device for sealing a passage through a stationary wall
between a first space, which is arranged to contain a gas, and a
second space, which is arranged to contain a liquid, wherein a
rotatable shaft is intended to extend in the passage through the
wall in such a way that a gap is formed, which extends around the
shaft between the shaft and the wall, a chamber being disposed
between the gap and the first space and extending around the shaft,
the device comprising: a rotatable disc fixedly disposed on the
shaft and extending outwardly from the shaft into the chamber,
wherein the chamber is arranged to contain liquid; and means for
forcing said liquid to rotate in the chamber at a rotary speed
which substantially exceeds the rotary speed of the shaft.
26. A device according to claim 25, wherein the forcing means
includes means for providing rotation in the chamber between the
disc and the first space.
27. A device according to claim 26, wherein the forcing means
includes a blade member operable to rotate independently of the
shaft.
28. A device according to claim 27, wherein the forcing means
includes a drive member operable to rotate the blade member at a
rotary speed which is higher than the rotary speed of the
shaft.
29. A device according to claim 27, wherein the blade member is
rotatably carried by a bearing member which is connected to at
least one of the shaft, the disc, and the wall.
30. A device according to claim 27, wherein the blade member
includes at least one set of blades which are disposed in the
chamber.
31. A device according to claim 27, wherein the blade member
includes a rotor member which extends outwardly in the chamber.
32. A device according to claim 31, wherein the blade member
includes a first set of blades disposed on the rotor member and
oriented towards the first space, and a second set of blades
disposed on the rotor member and oriented towards the disc.
33. A device according to claim 31, wherein the rotor member
includes a rotor of an electric motor having a stator disposed
outside the chamber.
34. A device according to claim 27, wherein the blade member forms
the chamber.
35. A device according to claim 34, wherein the blade member
includes a first set of blades disposed on a first limiting wall of
the chamber and oriented towards the disc, and a second set of
blades disposed on a second limiting wall of the chamber and
oriented towards the first limiting wall.
36. A device according to claim 25, wherein the forcing means
supplies liquid to the chamber at a speed and direction sufficient
to force the liquid in the chamber to said rotation.
37. A device according to claim 36, wherein the forcing means
includes at least a nozzle for said liquid supply, wherein said
nozzle extends in a substantially tangential direction into the
chamber.
38. A device according to claim 36, wherein the forcing means
include a pump for providing said liquid supply.
39. A device according to claim 25, wherein the chamber includes
several sub-chambers disposed between the gap and the first space
and extending around the shaft, and two rotatable discs rigidly
disposed on the shaft and extending outwardly from the shaft into a
respective one of said sub-chambers, wherein each of said
sub-chambers is arranged to contain liquid.
40. A device according to claim 39, wherein each sub-chamber is
disposed to permit a part of said liquid to flow into the
sub-chambers and at least partly be retained for said sealing of
the passage.
41. A device according to claim 25, wherein liquid flows from said
chamber to the second space.
42. A device according to claim 25, further comprising a wall
portion which partly defines the chamber and extends outwardly from
the gap.
43. A device according to claim 41, wherein the chamber between the
disc and the wall portion forms an outlet channel disposed to
reduce the speed of the liquid flowing from the chamber to the
second space.
44. A device according to claim 43, wherein the outlet channel
extends from a radially outer position at the periphery of the disc
to a radially inner position in proximity to the shaft.
45. A device according to claim 43, further comprising guide vanes
disposed in the outlet channel for conveying the liquid flowing
from the chamber to the second space.
46. A device according to claim 45, wherein the guide vanes are
disposed on the wall portion.
47. A device according to claim 43, wherein the wall portion is
rigidly connected to the wall.
48. A method for sealing a passage through a stationary wall
between a first space, which contains a gas, and a second space,
which contains a liquid, wherein a rotating shaft extends in the
passage through the wall in such a way that a gap is formed, which
extends around the shaft between the shaft and the wall, wherein
the method includes the steps of: providing a device including a
chamber, which is arranged between the gap and the first space and
extends around the shaft, and a rotating disc, which is rigidly
arranged on the shaft and extends outwardly from the shaft into the
chamber, wherein the chamber is arranged to contain liquid, and
forcing said liquid in the chamber to rotate at a rotary speed
which substantially exceeds the rotary speed of the shaft.
Description
THE BACKGROUND OF THE INVENTION AND PRIOR ART
[0001] The present invention refers to a device according to the
preamble of claim 1, and a method according to the preamble of
claim 25. The invention is particularly suitable for sealing
between a substantially stationary wall and a rotating shaft
extending through a passage in the wall. Examples of application
areas are ships and a propeller shaft extending through the hull of
the ship. Also other application areas are possible.
[0002] DE-A-1955016 discloses such a device for sealing a passage
through a wall between a first space, which is arranged to contain
a gas, and a second space, which is arranged to contain a gas, and
a second space, which is arranged to contain a liquid. A rotating
turbine shaft extends in the passage through the wall and is
journalled in a shaft bearing having a gap extending around the
shaft between the shaft and the wall. A rotating disc is rigidly
arranged on the shaft and extends outwardly from the shaft. A
stationary wall in the form of a further disc is provided between
the shaft bearing and the rotating disc. The stationary disc is
designed in such a way that it forms a space between the two discs.
Furthermore, supply conduits are provided for the supply of liquid
to this space via two nozzles. The liquid forms a rotating liquid
ring in the space.
[0003] DE 4212169 discloses a labyrinth sealing having a channel
between a rotating part and a stationary disc. The channel may be
supplied with oil via a supply channel, wherein a liquid level will
be formed in the channel due to the rotation of the disc.
[0004] GB 1284596 also discloses a labyrinth sealing with feeding
of liquid into a space formed by flange members from a rotating
rotor. A stationary disc extends into the space and includes
channels for said feeding of liquid and for discharging liquid from
the space.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is to provide a device
enabling a sufficient sealing of a passage for a rotating
shaft.
[0006] This object is achieved by the device initially defined,
which is characterised in that it includes means arranged to force
said liquid in the chamber to rotate at a rotary speed which
substantially exceeds the rotary speed of the shaft.
[0007] By such means it is possible to ensure in an efficient
manner that substantially no liquid will be transported from the
second space to the first gas-filled space. The liquid, which
rotates at the rotary speed which is higher than the speed of the
shaft, forms a liquid body in a radially outer part of the chamber.
This liquid body prevents substantially all media transport through
the passage. In relation to mechanical sealings the advantage of a
low friction and substantially no wear of essential sealing
components is of course also achieved. Advantageously, the wall is
stationary and consists, for instance, of a wall element of a ship
or a stationary plant.
[0008] According to an embodiment of the invention, the chamber is
arranged to permit that a part of said liquid flows into the
chamber and at least partly is retained in the chamber for said
sealing of the passage. Consequently, the liquid proper to be
sealed off will form a sealing liquid body which prevents said
media transport through the passage.
[0009] According to a further embodiment of the invention, said
means are arranged to provide said rotation in the chamber between
the disc and the first space. Consequently, the rotating liquid
body is formed in an outer part of the chamber between the disc and
the first space. The disc will thus prevent liquid from flowing
straight forward from the second space to the first space. The
liquid will instead be forced to the radially outer part of the
chamber, i.e. to the blocking liquid body.
[0010] According to a further embodiment of the invention, said
means include a blade member arranged to rotate independently of
the shaft. By such a blade member the desired rotation may be
achieved in an efficient manner. Advantageously, said means include
a drive member, which is arranged to rotate the blade member at a
rotary speed which is higher than the rotary speed of the shaft.
The blade member may be rotatably carried by a bearing member which
is connected to at least one of the shaft, the disc and the
wall.
[0011] According to a further embodiment of the invention, the
blade member includes at least one set of blades which are arranged
in the chamber. Advantageously, the blade member may include a
rotor member which extends outwardly in the chamber. The rotor
member may include one or two such sets of blades. One such rotor
member may be annular and extend around the shaft, wherein the
blades are arranged on the rotor member and uniformly distributed
around the shaft.
[0012] According to a further embodiment of the invention, the
blade member includes a first set of blades, which are arranged on
the rotor member and turned towards the first space, and a second
set of blades, which are arranged on the rotor member and turned
towards the disc.
[0013] According to a further embodiment of the invention, the
rotor member includes a rotor of an electric motor having a stator
which is provided outside the chamber. The stator and the electric
connections may thus be located outside the chamber and in the
first space.
[0014] According to a further embodiment of the invention, the
blade member forms the chamber. The blade member may then
advantageously include a first set of blades, which are arranged on
a first limiting wall of the chamber and turned towards the disc,
and a second set of blades, which are arranged on a second limiting
wall of the chamber and turned towards the first limiting wall.
[0015] According to a further embodiment of the invention, said
means are arranged to supply liquid to the chamber at such a speed
and direction that the liquid in the chamber is forced to said
rotation. Such means may include at least one nozzle for said
liquid supply, wherein said nozzle extends in a substantially
tangential direction into the chamber, and a pump for providing
said liquid supply.
[0016] According to a further embodiment of the invention, the
chamber includes several part chambers, which are arranged between
the gap and the first space, and extend around the shaft, and two
rotatable discs, which are rigidly connected to the shaft and
extend outwardly from the shaft in a respective one of said part
chambers, wherein each of said part chambers is arranged to contain
liquid. Advantageously, said part chambers may be arranged to
permit a part of said liquid to flow into the part chambers and at
least partly be retained for sealing of the passage.
[0017] According to a further embodiment of the invention, the
device is arranged to permit liquid to flow from the chamber to the
second space. In such a way it is ensured that liquid not may flow
from the chamber into the first space. The device may then include
a wall portion, which partly defines the chamber and extends
outwardly from the gap. The chamber may, between the disc and the
wall portion, form an outlet channel, which is arranged to reduce
the speed of the liquid flowing from the chamber to the second
space. In such a way it is possible to regain pressure and thus
reduce the energy consumption of the device. The outlet channel may
extend from a radially outer position at the periphery of the disc
to a radially inner position in the proximity of the shaft. In
order to further increase the pressure recovering, guide vanes may
be arranged in the outlet channel for conveying the liquid flowing
from the chamber to the second space. Advantageously, said guide
vanes are arranged on the wall portion.
[0018] The object is also achieved by the method defined in the
independent claim 25.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention is not to be explained more closely
through a description of various embodiments, shown by way of
example, and with reference to the drawings attached hereto.
[0020] FIG. 1 discloses a device according to a first embodiment of
the invention.
[0021] FIG. 2 discloses a device according to a second embodiment
of the invention.
[0022] FIG. 3 discloses a device according to a third embodiment of
the invention.
[0023] FIG. 4 discloses a set of blades of the device in FIG.
3.
[0024] FIG. 5 discloses a device according to a fourth embodiment
of the invention.
[0025] FIG. 6 discloses a set of guide vanes of the device in FIG.
5.
[0026] FIG. 7 discloses a device according to a fifth embodiment of
the invention.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION
[0027] FIGS. 1, 2, 3, 5 and 7 disclose different embodiments of a
device for sealing a passage 1 through a wall 2 between a first
space 3, which is arranged to contain a gas, and a second space 4,
which is arranged to contain a liquid. The wall 2 may form a
stationary wall element of a ship or of a stationary plant. A
rotatable shaft 5, for instance a propeller shaft of a ship,
extends in the passage 1 through the wall 2 in such a way that a
gap is formed, which extends around the shaft 5 between the shaft 5
and the wall 2. The shaft 5 is rotatable around the rotary axis
x.
[0028] The device according to the invention includes a chamber 8,
which is provided between the first space 3 and the second space 4,
and more precisely between the first space 3 and said gap of the
passage 1. The chamber 8 is annular and extends around the shaft 5.
The chamber 8 is formed of a first limiting wall 11, a second
limiting wall 12 and a third limiting wall 13. The three limiting
walls 11, 12, 13 thus enclose the chamber 8. The first limiting
wall 11 and the second limiting wall 12 extend substantially
radially outwardly and in parallel to each other. The third
limiting wall 13 extends substantially coaxially with the shaft 5
and between a radially outer end of the first limiting wall 11 and
a radially outer end of the second limiting wall 12. In the first
embodiment, the limiting walls 11, 12, 13 are fixed in relation to
the stationary wall 2.
[0029] The device also includes a rotatable disc 14, which is
fixedly arranged on the shaft 5. The disc 9 extends substantially
radially outwardly from the shaft 5 into the chamber 8 and divides
the chamber 8 in a first part volume 8a and a second part volume
8b.
[0030] Liquid from the second space 4 may thus via the passage 1
and said gap flow from the second space 4 into the chamber 8.
Consequently, the chamber 8 will contain liquid. Furthermore, the
device includes different means, which are to be explained more
closely in connection with the description of various embodiments
and which are arranged to prevent liquid from flowing through the
chamber 8 to the first space 3 by forcing the liquid in the chamber
8 to rotate at a relatively high rotary speed, i.e. a rotary speed
substantially exceeding the rotary speed of the shaft 5. The
rotating liquid will thus form a rotating liquid body in the first
part volume 8a of the chamber 8 between the disc 14 and the first
limiting wall 11.
[0031] According to the first embodiment disclosed in FIG. 1, said
means include a blade member 15, which includes a rotor member in
the form of a rotatable disc 16 and two sets of blades 17', 17".
The first set of blades 17' are provided on one side of the
rotatable disc 16 and the second set of blades 17" are provided on
the other side of the rotatable disc 16. The rotatable disc 16 is
provided on a cylindrical support member 18 of the blade member 15.
The support member 18 is substantially concentrically arranged
around the shaft with regard to the rotary axis x. The rotatable
disc 16 extends substantially radially outwardly in the chamber 8
from the support member 18 between the disc 14 and the first
limiting wall 11 of the chamber 8 The first set of blades 17' are
thus turned towards the disc 14 and the second set of blades 17"
are turned towards the first limiting wall 11. The blade member 15
includes also two sealing members 19', 19". A first such sealing
member 19' is turned towards the disc 14 and a second sealing
member 19" is turned towards the first limiting wall 11. The
sealing members 19', 19" are designed in such a way that they do
not abut the disc 14 and the first limiting wall 11, respectively,
when the blade member 15 rotates, but will abut sealingly the disc
14 and the limiting wall 11, respectively, when the blade member 15
is still standing and liquid flows from the second space 4 towards
the first space 3.
[0032] The blade member 15 is according to the first embodiment
rotatably carried by the shaft 5 by means of a bearing member 21,
which is provided between and connected to the cylindrical support
member 18 and the stationary wall 2 via a substantially cylindrical
projection 22 of the first limiting wall 11. The blade member 15 is
rotated independently of the shaft 5 by means of a schematically
disclosed drive motor 23, which via a drive belt 24 or any other
power transmission member is connected to the cylindrical support
member 18. The drive motor 23 is thus arranged to rotate the blade
member 15 at a rotary speed which is higher than the rotary speed
of the shaft 5, and in such a way create a rotating liquid body in
the radially outer part of the chamber 8. The level of the rotating
liquid is marked by the arrow 25.
[0033] Furthermore, the device is arranged to permit liquid to flow
from the chamber 8, and more precisely from the second part volume
8b of the chamber 8, to the second space 4. The second part volume
8b is thus located between the disc 14 and the second limiting wall
12 forming a wall portion 30 extending substantially radially
outwardly from the gap mentioned above. The second part volume 8b
and the gap thus form an outlet channel, which extends from a
radially outer position at the periphery of the disc 14 to a
radially inner position in the proximity of the shaft 5.
[0034] FIG. 2 discloses a second embodiment where the blade member
15 forms the chamber 8 which thus is rotatable. It is to be noted
that components having substantially the same function have been
provided with the same reference signs in the various embodiments.
The chamber 8 in the second embodiment thus is formed of a separate
wall element 11, 12, 13, which is rotatable around the shaft 5
independently of the rotation of the shaft 5 and which also
includes a first limiting wall 11, a second limiting wall 12 and a
third limiting wall 13. Also in this embodiment, the limiting walls
11 and 12 extend substantially radially outwardly and in parallel
to each other, and the limiting wall 13 extends substantially
coaxially with the shaft 5 and between a radially outer end of the
limiting walls 11 and 12. The disc 14 extends substantially
radially outwardly from the shaft 5 and into the chamber 8. A wall
portion 30 extends substantially radially outwardly from said gap
and substantially in parallel with the disc 14. The wall portion 30
is rigidly connected to the stationary wall 2. In the second
embodiment, the second part volume 8b of the chamber 8 and thus an
outlet channel for liquid from the radially outer part of the
chamber 8 is formed between the disc 14 and the wall portion 30. In
the second embodiment, the first part volume 8a is formed partly
between the first limiting wall 11 and the disc 14 and partly
between the second limiting wall 12 and the wall portion 30.
[0035] According to the second embodiment, the blade member 15
includes a first set of blades 17', which are arranged on the first
limiting wall 11 and turned towards the disc 13, and a second set
of blades 17", which are arranged on the second limiting wall 12
and turned towards the wall portion 30. The first set of blades 17'
and the second set of blades 17" thus create a rotating liquid body
in a radially outer part of the respective part volume 8a, so that
liquid extends to the level indicated by the arrows 25.
[0036] The blade member 15 is according to the second embodiment
rotatably carried by the stationary wall 2 by means of a first
bearing member 21', which is arranged between and connected to the
stationary wall 2 and a substantially cylindrical projection 31 of
the first limiting wall 11, and a second bearing member 21", which
is arranged between and connected to the stationary wall 2 and a
substantially cylindrical projection 32 of the second limiting wall
12. A first sealing member 19' is arranged between the first
substantially cylindrical projection 31 and the shaft 5 in such a
way that the first sealing member 19' does not abut the shaft 5
when the blade member 15 rotates but only when the blade member 15
is still standing. A second sealing member 19" is arranged between
the second substantially cylindrical projection 32 and a
substantially cylindrical part 33 of the stationary wall 2. The
substantially cylindrical part 33 extends substantially
concentrically from the wall portion 30 between the shaft 5 and the
projection 32, wherein said gap is formed between the part 33 and
the shaft 5. The sealing member 19" does not abut the part 32 when
the blade member 15 rotates but only when the blade member 15 is
still standing.
[0037] FIGS. 3 and 4 disclose a third embodiment where the blade
member 15 includes an annular rotor 40 of an electric motor. The
blade member 10 and the rotor 40 are provided in the chamber 8 and
more precisely in the first part volume 8a. Also in this
embodiment, the chamber 8 is formed by a first limiting wall 11, a
second limiting wall 12 and a third limiting wall 13, which thus
enclose the chamber 8. In the same way as in the first embodiment,
the three limiting walls 11, 12, 13 are rigidly connected to the
stationary wall. The electric motor also includes a stator 41,
which has a winding 42 and which is arranged outside the chamber 8,
and more precisely outside the first limiting wall 13. The electric
motor may for instance be an asynchronous motor or a so-called
PMSM-motor. The blade member 15 is rotatably carried by the shaft 5
by means of a first bearing member 21' and a second bearing member
22'. No sealing members are disclosed in FIG. 3, but may for
instance be arranged between the shaft 5 and the substantially
cylindrical projections 43, 44 of the limiting walls 11 and 22,
respectively.
[0038] The blade member 15 includes a first set of blades 17',
which are arranged on the rotor 40 and turned towards the first
limiting wall 11, and a second set of blades 17", which are
arranged on the rotor 40 and turned towards the disc 14.
[0039] FIG. 4 discloses schematically an example of a set of blades
17" of the third embodiment. The blades 17" are arranged on an
annular carrier 45 which is mounted on the annular rotor 40.
[0040] FIG. 5 discloses a fourth embodiment of the invention. The
chamber 8 is also here formed by a first limiting wall 11, a second
limiting wall 12 and a third limiting wall 13. The three limiting
walls 11, 12, 13 thus enclose the chamber 8 and are fixedly
connected to the stationary wall 2. In this embodiment, said means
are arranged to supply liquid to the first part volume 8a of the
chamber 8 at such a speed and direction that the liquid in the
chamber 8 is forced to rotate at a rotary speed exceeding the
rotary speed of the shaft 5. The means include a set of nozzles 50
for said liquid supply. The nozzles 50 extend in a substantially
tangential direction into the chamber 8 seen in an axial section.
The liquid is supplied to the nozzles 50 by means of a
schematically disclosed pump 51 via conduit members 52. A sealing
member 19 is arranged between the first limiting wall 11 and the
shaft 5.
[0041] The outlet channel mentioned above, which partly is formed
by the second part volume 8b of the embodiments disclosed, is
arranged to reduce the speed of the liquid flowing from the chamber
8 to the second space 4. The outlet channel extends from a radially
outer position at the periphery of the disc 14 to a radially inner
position in the proximity of the shaft 5. By said speed reduction a
pressure recovery and thus a lower energy consumption of the device
is achieved. In order to further increase the pressure recovery,
guide vanes 60 of the type disclosed in FIG. 6 may be arranged in
the outlet channel for conveying the liquid flowing from the
chamber 8 to the second space 8b. In the fourth embodiment, the
guide vanes 60 are arranged on the second limiting wall 12, forming
a wall portion 30, and in the second embodiment on the wall portion
30. Also the device according to the first and third embodiments
may be provided with such guide vanes.
[0042] FIG. 7 discloses a fifth embodiment, which differs from the
other embodiments by the fact that the chamber 8 includes three
part chambers 8', 8" and 8'". Except for this difference, the
construction and the function of the device according to the fifth
embodiment in FIG. 7 is similar to the construction and the
function of the second embodiment in FIG. 2. The part chambers 8',
8" and 8'" have been formed by means of two intermedient walls 71
and 72, which are provided with blades 17'" and 17"", respectively,
and which extend substantially radially inwardly from the third
limiting wall 13. Furthermore, the fifth embodiment includes two
rotatable discs 14' and 14" which extend into a respective part
chamber 8' and 8", respectively, and two wall portions 30' and 30",
which are provided with guide vanes 60' and 60", respectively,
which correspond to the guide vanes 60 in FIG. 2. The wall portions
30' and 30" extend substantially radially outwardly from the
cylindrical part 33 and into a respective part chamber 8" and 8'",
respectively. The central part chamber 8" includes the second part
volume 8b and is thus substantially identical to the chamber in
FIG. 2, whereas the part chamber 8' merely receives the disc 14'
and the part chamber 8'" merely receives the wall portion 30". It
is to be noted that the chamber 8 may include another number part
chambers than appears from the embodiments disclosed. For instance,
it may include the two part chambers 8' and 8", and the two
rotatable discs 14' and 14", but merely one wall portion 30'. Also
other configurations are possible and especially it is to be noted
that the chamber 8 may include more than three part chambers
disclosed.
[0043] The invention is not limited to the embodiments disclosed
but may be varied and modified within the scope of the following
claims.
* * * * *