Note: Descriptions are shown in the official language in which they were submitted.
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BEARING ASSEMBLY HAVING FILTER DEVICE
Description
Scope of the invention
The invention relates to a bearing arrangement having a bearing transversed by
a
medium, in particular water.
For bearing arrangements having a bearing transversed by a medium, for example
water, it is common in the practice to filter the medium flowing through the
bearing, in
particular water in the case of a water-lubricated bearing, to keep particles
away from
the bearing. For this purpose, filter systems with a particle filter are for
example
provided which are set up downstream of the inflow side of the bearing so that
the
medium only enters the bearing after passing the particle filter. The flow-
through of
the medium, i.e. the quantity of medium flowing through the bearing per time
unit
decreases to the same extent in which the particle filter absorbs particles
and
becomes contaminated. Highly contaminated particle filters can virtually bring
the
flow-through of the medium through the bearing to a halt, thus severely
impairing the
lubrication or cooling of the bearing by the medium. This disadvantage in
particular
occurs, if the contaminated particle filter cannot be readily exchanged, for
example in
tidal current power stations, whose main tube bearings are submerged under
water
and not readily accessible.
Furthermore, the structural integration of filter systems into the bearing of
the bearing
arrangement is known.
DE 1 132 738 A describes a bearing arrangement for the end section of the
counter
shaft of a counter, in particular a fluid counter, wherein the end section of
the shaft is
arranged in a bearing box transversed by water and wherein a filter system is
assigned to a face of the storage box which comprises a ring made of a filter
, .
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material, wherein the ring surrounds a shaft. The ring prevents both the
inflow into
the bearing box as well as the outflow of the medium out of the bearing box.
JP 2003042159 AA (Abstract) describes a bearing arrangement for a dynamic
thrust
bearing, wherein a centrifugal separation chamber is provided which is
arranged at a
distance from the rotational axis of the shaft, wherein the separation chamber
has a
fluid connection with an inflow and an outflow area of the bearing
arrangement.
JP 08338425 AA (Abstract) describes a bearing arrangement with a shaft
positioned
in a bearing, wherein the bearing is integrated in a bearing case. The bearing
arrangement is provided to retain a shaft submerged under water, wherein the
water
serves as lubricant of the shaft. An inflow area is provided on the inflow
side, in
which a means of motion directs the water into a filter of a filter system. An
outflow
area is provided on the outflow side which the water enters into after flowing
through
the bearing. The means of motion has a torque-resistant connection with the
shaft
and is essentially designed as a radially protruding section. The means of
motion
comprises an inlet opening, from which the water either flows through the fine
filter or
past the fine filter toward the outflow area. The fine filter is rigidly
connected to the
means of motion.
JP 08135653 AA (Abstract) describes a bearing arrangement for a shaft
submerged
under water which is integrated in a bearing transversed by water. A motion
plate is
arranged between the bearing and the bearing retainer of the bearing on the
inflow
side which directs the water radially outward to a diversion plate arranged
underneath an angle from where the water is directed either radially inward to
the
fine filter or parallel to the shaft into an outflow area. The filter of the
filter system has
a distance to the shaft to allow the particles to pass the filter. If the
shaft stops
moving, the motion plate stops moving too and no water passes the fine filter.
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DE 10 2007 003 618 A1 describes a bearing arrangement in a first exemplary
embodiment (Fig. 3), in which a cartridge filter is provided on the inflow
side. After the
water has passed said filter, it flows into a conically tapered area.
DE 10 2007 003 618 A1 describes a bearing arrangement in a second exemplary
embodiment (Fig. 2) in which a cartridge filter with a downstream filter pump
is provided
on the inflow side.
The subsequently filed patent application DE 10 2008 052 287.2 dated October
18,
2008 describes a bearing arrangement having a bearing transversed by a medium,
in
particular water, a filter system comprising a protective cap arranged on the
inflow side
and a fine filter arranged downstream of the protective cap. Furthermore, the
bearing
arrangement comprises a conveyor system for the medium arranged downstream of
the
bearing on the outflow side and which controls the flow of the medium through
the
bearing.
Object of the invention
The object of the invention is to specify a bearing arrangement which
sustainably
maintains the filter efficiency.
Abstract of the invention
The object for the bearing arrangement is in particular solved according to
the invention
in that the conveyor system is arranged between the protective cap and the
fine filter.
Consequently, the conveyor system is arranged within the filter system, namely
between the protective cap and the fine filter and ensures that a pressure
difference is
built up in front of the fine filter, so that the fine filter can be
transversed by an
adjustable quantity of lubricant, even if the permeability of the fine filter
decreases due
to increasing contamination of the filter material.
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The conveyor system has the additional advantage that it suppresses the
penetration
of particles into the gap between the protective cap and the fine filter.
The invention, its properties and advantages as well as advantageous
embodiments
of the invention are described below with reference to water as the medium
flowing
through the bearing; however, it is understood, that a different medium than
water,
specifically a different fluid can be provided to flow through the bearing.
The conveyor system preferably has a torque-resistant connection with the
shaft.
Then, the quantity of medium, specifically the water, flowing through the
bearing is
dependent on the rotational speed of the shaft which acts as drive for the
conveyor
system.
The conveyor system is preferably designed as perforated ring wheel. In
addition to
the perforation, it may comprise shovel-like structures to support or increase
the
water conveyed toward the fine filter. The ring wheel is particularly suitable
to
suppress the penetration of contaminated water to the fine filter if the
bearing is
stopped.
Alternatively or in addition to the design of the conveyor system as
perforated ring
wheel, the conveyor system is preferably designed as conveyor propeller. The
conveyor propeller has a shovel-like structure which allows the aspiration of
water
from the area surrounding the protective cap. It is understood that the
conveyor
propeller can be provided in addition to the ring wheel, wherein the conveying
effect
on the water is essentially achieved with the conveyor propeller, while the
covering
pane essentially prevents the re-penetration of contaminated water to the fine
filter, if
the conveyor propeller is stopped. In this case, the covering pane can be
designed
as a flat disk with holes.
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Again alternatively or in addition to a design of the conveyor system as
perforated ring
wheel or as conveyor propeller, the conveyor system is preferably arranged on
a side of
the protective cap facing away from the area of the protective cap approached
by the
flow. This allows the exploitation of the rotation of the protective cap to
convey the
water, especially in the case where a particularly preferably embodiment
provides that
the conveyor system is designed as a worm conveyor.
In a preferred embodiment of the invention, the conveyor system, in particular
the worm
conveyor can also be attached to the fine filter, especially in the event that
the
protective cap is not arranged in such a way that it rotates along with the
shaft.
Preferably, the shaft is designed as sleeve shaft at least in sections and the
sleeve shaft
comprises a radial borehole which opens into an inflow area provided
downstream on
the inflow side of the bearing. The motion of the water inside the filter
toward the axis of
the shaft can develop the effect of a rotational filter, with which in
particular heavy
components of the medium such as particles can be kept away. The design of the
shaft
as sleeve shaft allows the conveyance of the filtered water to the single
bearing of the
bearing arrangement or to two or a plurality of bearings arranged at a
distance from
each other, wherein the water exits the sleeve shaft at the site of the radial
borehole
and enters the inflow area provided downstream on the inflow side of the
bearing. It is in
particular possible to provide a single filter system for a bearing
arrangement which
comprises two or more bearings arranged at a distance from each other in the
direction
of the shaft, so as to simplify the set up as well as the maintenance of the
bearing
arrangement.
Further advantages and properties of the invention can be gathered from the
description herein of exemplary embodiments.
The invention is described and explained in detail below with reference to the
enclosed
drawings.
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Brief description of the drawings
Fig. 1 shows a schematic section through a first exemplary embodiment of a
bearing
arrangement according to the invention,
Fig. 2 shows a schematic section through a second exemplary embodiment of a
bearing arrangement according to the invention, and
Fig. 3 shows a schematic section through a third exemplary embodiment of a
bearing
arrangement according to the invention.
Detailed description of the drawings
Fig. 1 shows a bearing arrangement comprising a first bearing 1 transversed by
water as medium and a second bearing 2 arranged at a distance from the first
bearing 1 as well as a common filter system 3 assigned to both bearings 1, 2
as well
as a shaft 4 pivotably integrated in both bearings 1, 2. The filter system 3
is arranged
downstream of the inflow side of both bearings 1, 2 in the sense that the
water first
needs to pass the filter system 3 in order to reach the respective bearing 1,
2. A
torque-resistant connection is provided between the shaft 4 and a rotor 5
which is
driven by the water flowing around the bearing assembly and whose kinetic
energy is
converted into electrical energy by a generator 6. As a result, the bearing
arrangement is designed as a component of a tidal current power station not
illustrated further and submerged under water.
The second bearing 2 is arranged at a considerable distance from the common
filter
system 3 in the direction of the shaft 4. To allow the inflow of filtered
water from the
filter system 3 to the second bearing 2, the shaft 4 is designed as sleeve
shaft in
sections, so that filtered water is carried to a radial borehole 11 in the
corpus of the
hollow section 12 along said section of the shaft 4. The radial borehole 11
opens into
an inflow area 13 arranged downstream in relation to the flow of the second
bearing
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2, whereby the water enters an outflow area 14 after flowing through the
second
bearing 2 and exits the bearing arrangement.
The filter system 3 is designed in three parts and comprises a protective cap
15, a
screen filter 16 and a fine filter 17. The protective cap 15 has a conical, in
particular
obtuse conical shape in the direction of the approaching medium (arrow 18).
Coarse
particles such as for example smaller stones carried along in the approaching
medium bounce off of said protective cap 15. The protective cap 15 comprises
an
inlet opening 19, facing away from the direction 18 of the approaching water
and
through which water can enter into the filter system 3. After passing the
inlet opening
19, the water flows along the obtuse conical inner wall area of the protective
cap 15
in the direction of the axis of the shaft 4 and reaches the screen filter 16,
which is
essentially arranged in the direction of the axis of the shaft 4. The screen
filter 16
retains larger particles contained in the water. After passing the screen
filter 16, the
water reaches a collecting area 19, arranged downstream relative to the flow
of the
fine filter 17. From the collecting area 20, the water runs through the fine
filter 17
which is designed with two layers and comprises two filter fleece layers which
can
easily be exchanged independently of each other and have a solid consistence,
either directly into an inflow area 8 of the first bearing 1 or ¨ in an
alternative flow
pathway ¨ into the section 12 of the shaft 4 designed as sleeve shaft toward
the
radial borehole 11, which leads into the inflow area 13 of the second bearing
2.
The water that passed the first bearing 1 enters into an outflow area 9 and is
subsequently directed away from the shaft 4 via a radial borehole 21 provided
in a
case 24 in which the bearing 4 is positioned. A covering pane 7 is provided on
the
outflow area 9 of the first bearing, which is designed as perforated circular
ring and
prevents the penetration of contaminated water into the first bearing 1, in
particular in
the event that the shaft 4 is stopped and no water is conveyed through the
filter
system 3. The covering pane 7 of the first bearing 1 has a torque-resistant
connection with the shaft 4 and develops a conveying effect in the direction
of the
flow (arrow 18).
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Another covering pane 10 is arranged on the outflow area 14 of the second
bearing
2, which also has a torque-resistant connection with the shaft and is designed
to
prevent the penetration of contaminated water into the second bearing 2 if the
shaft 4
is stopped.
Furthermore, the bearing arrangement comprises a conveyance system 22 for the
water which is arranged between the protective cap 15 and the fine filter 17.
In the first exemplary embodiment illustrated in Fig. 1, the conveyance system
22 is
designed as perforated ring wheel arranged on the inlet opening 19 fastened on
the
protective cap 15, which covers the inlet opening 19 and prevents the
penetration of
contaminated water into the area between the protective cap 15 and the screen
filter
16. The protective cap 15 has a torque-resistant connection with the shaft 4,
so that
the perforated ring wheel develops a conveying effect for the water toward the
fine
filter 16 when the shaft 4 is rotated. The borehole diameter of the
perforations of the
ring wheel decrease in the flow direction, resulting in a conveying effect
toward the
fine filter 17 when the ring wheel is turned. Alternatively or in addition to
the
perforated ring wheel, the conveyance system 22 can also comprise a conveyance
propeller arranged on the protective cap 15 with a torque-resistant
connection.
In the following description of the second or third exemplary embodiment based
on
Fig. 2 and Fig. 3, identical reference numbers refer to identical properties
or
properties with a comparable technical effect. The purpose is in particular to
emphasize the differences compared to Fig. 1 with respect to the arrangement
of the
conveyance system 22.
Fig. 2 shows a bearing arrangement with a conveyance system 22 arranged on a
side 23 of the protective cap 15 facing away from the area of the protective
cap 15
approached by the flow. The cross-sectional profile of the side 23 facing away
from
the area of the protective cap approached by the flow conically expands toward
the
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shaft 4, wherein the conveyance system 22 is designed as worm conveyor, whose
six channels on the side 23 are designed as spiral shaped circumferential
elevations.
The protective cap 15 and hence the conveyance system 22 has a torque-
resistant
connection with the shaft 4, and as a result the worm conveyor transports
water from
the inlet opening 19 toward the fine filter 17 when the shaft 4 is turned.
Fig. 3 shows a bearing arrangement in which no torque-resistant connection is
provided between the protective cap 15 and the shaft 4, but in which the
protective
cap is fixed in relation to the shaft 4. The protective cap 15 is rigidly
connected with
the case 24. The screen filter 16 is arranged in a filter retainer 25,
concentrically
arranged with and within the conical protective cap 15 and has a torque-
resistant
connection with the shaft 4. A passage is provided between the filter retainer
25 and
the side 23 facing away from the area of the protective cap 15 approached by
the
flow, within which the conveyance system 22 is provided. The conveyance system
22 is designed as three-channel worm conveyor, whose channels are designed as
spiral-shaped elevations surrounding the circumference of the filter retainer
25 facing
the side 23. A major difference in the relative speed between the protective
cap 15
and the conveyance system 22 occurs when the shaft 4 is turned and a high
pressure difference is built up as a result, thus allowing especially the
selection of a
particularly fine pored material for the fine filter 17.
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Reference list
1 First bearing
2 Second bearing
3 Filter system
4 Shaft
5 Rotor
6 Generator
7 Covering pane of the first bearing 1
8 Inflow area of the first bearing 1
9 Outflow area of the first bearing 1
10 Covering pane of the second bearing
11 Radial borehole
12 Hollow section
13 Inflow area of the second bearing 2
14 Outflow area of the second bearing 2
Protective cap
16 Screen filter
17 Fine filter
18 Direction of the approaching water
19 Inlet opening
Collecting area
21 Radial borehole
22 Conveyance system
23 Side of the protective cap 15
24 Case
Filter case
