US20050279061A1 - Vents for fluid systems - Google Patents
Vents for fluid systems Download PDFInfo
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- US20050279061A1 US20050279061A1 US11/178,325 US17832505A US2005279061A1 US 20050279061 A1 US20050279061 A1 US 20050279061A1 US 17832505 A US17832505 A US 17832505A US 2005279061 A1 US2005279061 A1 US 2005279061A1
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- Prior art keywords
- vent
- fluid
- chamber
- flow
- flow path
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D45/00—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces
- B01D45/12—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces
- B01D45/16—Separating dispersed particles from gases or vapours by gravity, inertia, or centrifugal forces by centrifugal forces generated by the winding course of the gas stream, the centrifugal forces being generated solely or partly by mechanical means, e.g. fixed swirl vanes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/18—Lubricating arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/18—Lubricating arrangements
- F01D25/183—Sealing means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15C—FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
- F15C1/00—Circuit elements having no moving parts
- F15C1/16—Vortex devices, i.e. devices in which use is made of the pressure drop associated with vortex motion in a fluid
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- This invention relates to vents for fluid systems. More particularly, but not exclusively, it relates to vents for bearing chambers, for example in gas turbine engines.
- Gas turbine engines typically include one or more shafts supported on oil-lubricated bearings. These bearings are housed in bearing chambers, and there are seals between the chamber and the shaft to inhibit the leakage of lubricating oil. It is usually arranged that, under normal operating conditions, the pressure outside a bearing chamber is slightly higher than the pressure within it. This differential pressure ensures that there is a continuous counterflow of air inwards through the seals and oil leakage is avoided. However, under certain transient conditions the pressures may change so that the differential pressure is reversed. In these circumstances, oil will tend to pass through the seals and out of the bearing chamber.
- Labyrinth seals generally require a large and heavy buffer system to operate properly; some such systems also incorporate drains to dispose of any oil that does leak, adding further weight and complexity. Carbon seals can operate with a smaller counterflow of air, which may save weight in the buffer system, but they are still prone to allow oil to escape if the differential pressure is reversed.
- a separate vent may be provided for the bearing chamber, to allow an outward flow of air, when required, other than through the bearing chamber seals.
- Examples of such devices are simple vents, with or without restrictors, and spring-loaded valves; but oil can still escape from the bearing chamber through these devices, and so they do not solve the fundamental problem.
- a vent for a fluid system includes a chamber through which fluid can flow along either a first flow path or a second flow path, in which the resistance to fluid flow is relatively high when the fluid follows the first flow path and the resistance to fluid flow is relatively low when the fluid follows the second flow path.
- the first flow path is associated with fluid flow in one direction through the chamber
- the second flow path is associated with fluid flow in the opposite direction through the chamber
- the chamber has two ports, the two ports lying in planes substantially perpendicular to each other.
- the chamber is substantially cylindrical.
- one of the two ports is arranged to be substantially coaxial with the chamber and the other of the two ports is arranged to be substantially tangential to the chamber.
- the substantially tangential port may have a convergent or convergent-divergent inner profile.
- An annular wall member may protrude generally axially from the coaxial port into the chamber.
- the fluid flow at least when following the first flow path, may include a component of higher density than the fluid, and the flow of the fluid along the first flow path may act to separate the higher density component from the fluid.
- the chamber may be extended in an axial direction to receive the higher density component separated from the fluid. Means may be provided to carry the higher density component out of the chamber.
- the higher density component may comprise a lubricant.
- the vent may be a part of a bearing chamber.
- the vent may be a part of a gas turbine engine.
- a venting arrangement for a fluid system comprises a first vent and a second vent, the first and second vents being arranged in flow series, in which the first and second vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of the first vent, and when fluid flows through the venting arrangement in the other, opposite direction it follows the first flow path through the chamber of the second vent.
- a venting arrangement for a fluid system comprises a plurality of vents, the vents being arranged in flow series, in which the vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of each vent in succession, and when fluid flows through the venting arrangement in the other, opposite direction it follows the second flow path through the chamber of each vent in succession.
- the venting arrangement may be a part of a bearing chamber.
- the venting arrangement may be a part of a gas turbine engine.
- vortex throttle or vortex diode
- vortex diode a device, known as a vortex throttle or vortex diode, which is well known in the art of fluidics. This device will be described in more detail later in the specification. Those skilled in the art of fluidics will be aware of the distinctions between a vortex throttle and a vortex diode; for the purposes of this specification such distinctions are generally unimportant and for the sake of clarity the term “vortex diode” will be used throughout.
- Fluidics is a discipline whose origins lie in attempts to overcome the susceptibility of electronic circuits to interference from electromagnetic radiation. It teaches the construction of circuits, analogous to electrical or electronic circuits, in which a flow of fluid, rather than a flow of electrons, performs the work. Devices such as switches, diodes, amplifiers and so on, familiar in an electrical context, can also be made to work satisfactorily in fluidic circuits. Fluidics has received relatively little attention in recent years, although its principles have been applied (on a larger scale) in fields such as sewage flow control, where the absence of moving parts in fluidic components permits the construction of reliable valves that are not prone to blockage.
- FIG. 1 is a schematic sectional view of a vortex diode of known type, showing the air flows in the “low resistance” direction;
- FIG. 2 is a schematic sectional view taken on the line A-A in FIG. 1 ;
- FIG. 3 is a schematic sectional view of a vortex diode of known type, showing the air flows in the “high resistance” direction;
- FIG. 4 is a schematic sectional view taken on the line B-B in FIG. 3 ;
- FIG. 5 is a schematic representation of a bearing chamber having a vent according to one aspect of the invention.
- FIGS. 6 and 7 are schematic sectional views of two alternative embodiments of a bearing chamber vent according to one aspect of the invention.
- FIG. 8 is a schematic sectional view of a further alternative embodiment of a bearing chamber vent according to one aspect of the invention.
- FIG. 9 is a schematic representation of a bearing chamber having a venting arrangement according to an alternative aspect of the invention.
- FIG. 10 is a schematic representation of a bearing chamber having a venting arrangement according to a further alternative aspect of the invention.
- a vortex diode 20 of known type comprises structure 22 defining a cylindrical volume 24 .
- Two ducts of circular cross-section are in fluid communication with the cylindrical volume 24 .
- Duct 26 is coaxial with the cylindrical volume 24 and duct 28 is tangential to the cylindrical volume 24 .
- FIGS. 3 and 4 the arrangement of the vortex diode 20 is exactly as in FIGS. 1 and 2 .
- the geometry of the cylindrical volume 24 will tend to urge the fluid into vortical flow, as shown by the arrow 42 in FIG. 3 .
- the fluid will then exit the cylindrical volume 24 via the duct 26 (as shown by the arrow 44 in FIG. 4 ), but because of the swirling motion imparted to the flowing fluid the resistance to flow will be relatively high.
- any higher density component entrained in the fluid will tend to be urged outwards by centrifugal force, and will tend to be separated from the fluid.
- the duct 28 may have an inner profile that converges towards the cylindrical volume 24 , or may have an inner profile that is convergent-divergent. When fluid flows into the cylindrical volume 24 through the duct 28 , as shown in FIGS. 3 and 4 , such an inner profile will increase the velocity of the fluid flowing into the cylindrical volume 24 , for a given pressure drop, and thus increase the efficiency of the separation.
- FIG. 5 shows a schematic sectional view of a bearing chamber 50 of a gas turbine engine (not shown) having a vent according to one aspect of the invention.
- Conduit 52 links the bearing chamber 50 to the tangential port 54 of a vortex diode 56 of known type.
- Conduit 58 links the coaxial port 60 of the vortex diode 56 to a region 62 outside the bearing chamber 50 .
- the vent is shown attached to the side of the bearing chamber. However, it is envisaged that it could equally well be integrated into the structure of the bearing chamber, or alternatively be entirely separate from the bearing chamber and mounted separately within the engine.
- the pressure in the bearing chamber 50 will be lower than the pressure in the region 62 outside the bearing chamber 50 , and so there will be a flow of air from the region 62 into the bearing chamber 50 . Air will therefore flow into the vortex diode 56 through the coaxial port 60 , and out through the tangential port 54 . The air flow through the vortex diode 56 will therefore be substantially as shown by the arrows 30 and 32 in FIGS. 1 and 2 , and the resistance to flow will be relatively low.
- the relative pressures in the engine may change such that the pressure in the bearing chamber 50 is higher than the pressure in the region 62 . There will then be a flow of air from the bearing chamber 50 into the region 62 . Air will therefore flow into the vortex diode 56 through the tangential port 54 , and out through the coaxial port 60 . The air flow through the vortex diode 56 will therefore be substantially as shown by the arrows 40 , 42 and 44 in FIGS. 3 and 4 , and the resistance to flow will be relatively high. It is likely that some oil or similar lubricant will be entrained in the air flow, and (as explained in the discussion of FIGS. 3 and 4 ) the swirling motion imparted to the air will tend to urge any such component outwards by centrifugal force, and will thus tend to separate it from the air.
- FIGS. 6 and 7 show two alternative embodiments of the vortex diode used in the vent of FIG. 5 , in which provision is made to collect oil separated out from the air flow.
- the cylindrical volume 24 is extended downward by the addition of an annular volume 64 .
- the whole of the cylindrical volume 24 is enlarged downward.
- any oil separated out from the air flow will collect in the annular volume 64 (of FIG. 6 ) or in the lower part of the enlarged cylindrical volume 24 (of FIG. 7 ). Subsequently, when the air flow returns to normal, as shown in FIGS.
- the separated oil can flow through the conduit 66 back into the duct 28 and subsequently back to the bearing chamber, impelled by the normal flow of air out of the vortex diode 20 through the duct 28 (as shown by arrow 32 in FIG. 1 ).
- the conduits 66 and 28 may be arranged so that the separated oil will tend to flow back to the bearing chamber under the action of gravity.
- FIG. 8 shows an alternative embodiment of a vortex diode having a higher resistance to flow in the “low resistance” direction.
- An annular collar 68 protrudes into the cylindrical volume 24 .
- the duct 28 is of smaller diameter than in the vortex diode of FIG. 1 . It will be appreciated, by one skilled in the art, that changes may be made to the protrusion of the collar 68 , and to the diameters of the two ducts 26 and 28 , so as to tailor the flow resistance of the vortex diode in both directions to suit particular applications.
- FIG. 9 shows a bearing chamber having a venting arrangement according to an alternative aspect of the invention, which comprises two vortex diodes in flow series.
- Conduit 52 links the bearing chamber 50 to the tangential port 70 of a first vortex diode 72 .
- Conduit 74 links the coaxial port 76 of the first vortex diode 72 to the coaxial port 78 of a second vortex diode 80 .
- Conduit 82 links the tangential port 84 of the second vortex diode 80 to a region 62 outside the bearing chamber 50 .
- the air will subsequently flow through the conduit 74 and through the first vortex diode 72 , entering through the coaxial port 76 and exiting through the tangential port 70 .
- the air flow through the first vortex diode 72 will therefore be substantially as shown by arrows 30 and 32 in FIGS. 1 and 2 , and the resistance to flow will be relatively low.
- venting arrangement is shown attached to the side of the bearing chamber. However, it is envisaged that it could equally well be integrated into the structure of the bearing chamber, or alternatively be entirely separate from the bearing chamber and mounted elsewhere within the engine.
- the two vortex diodes may be arranged differently in relation to each other, provided that their coaxial ports are always linked together, without affecting the operation of the venting arrangement.
- FIG. 10 shows a bearing chamber having a venting arrangement according to a further aspect of the invention, comprising three vortex diodes arranged in flow series.
- Conduit 52 links the bearing chamber 50 to the tangential port 54 of a first vortex diode 56 .
- a conduit 57 links the coaxial port 60 of the first vortex diode 56 to the tangential port 54 of a second vortex diode 56 .
- a further conduit 57 links the coaxial port 60 of the second vortex diode to the tangential port 54 of a third vortex diode 56 , in like manner.
- Conduit 58 links the coaxial port 60 of the third vortex diode 56 to a region 62 outside the bearing chamber 50 .
- venting arrangement is shown attached to the side of the bearing chamber. However, it is envisaged that it could equally well be integrated into the structure of the bearing chamber, or alternatively be entirely separate from the bearing chamber and mounted elsewhere within the engine.
- the three vortex diodes may be arranged differently in relation to each other, provided that the ports of the successive vortex diodes are always connected in the manner shown in FIG. 10 , without affecting the operation of the venting arrangement.
- each of the vortex diodes could have different flow characteristics (as discussed in connection with FIG. 8 ), for example to optimize the oil separation.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Theoretical Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
Abstract
A vent for a fluid system includes a chamber through which fluid can flow along either a first flow path or a second flow path, in which the resistance to fluid flow is relatively high when the fluid follows the first flow path and relatively low when the fluid follows the second flow path. In a preferred embodiment the chamber is substantially cylindrical and has two ports, one of which is substantially coaxial with the chamber and the other of which is substantially tangential to the chamber. The fluid flow, at least when following the first flow path, may include a component of higher density than the fluid, and the flow of the fluid along the first flow path may act to separate the higher density component from the fluid.
Description
- This invention relates to vents for fluid systems. More particularly, but not exclusively, it relates to vents for bearing chambers, for example in gas turbine engines.
- Gas turbine engines typically include one or more shafts supported on oil-lubricated bearings. These bearings are housed in bearing chambers, and there are seals between the chamber and the shaft to inhibit the leakage of lubricating oil. It is usually arranged that, under normal operating conditions, the pressure outside a bearing chamber is slightly higher than the pressure within it. This differential pressure ensures that there is a continuous counterflow of air inwards through the seals and oil leakage is avoided. However, under certain transient conditions the pressures may change so that the differential pressure is reversed. In these circumstances, oil will tend to pass through the seals and out of the bearing chamber.
- Various types of sealing arrangement are known that attempt to prevent oil leakage. Labyrinth seals generally require a large and heavy buffer system to operate properly; some such systems also incorporate drains to dispose of any oil that does leak, adding further weight and complexity. Carbon seals can operate with a smaller counterflow of air, which may save weight in the buffer system, but they are still prone to allow oil to escape if the differential pressure is reversed.
- A separate vent may be provided for the bearing chamber, to allow an outward flow of air, when required, other than through the bearing chamber seals. Examples of such devices are simple vents, with or without restrictors, and spring-loaded valves; but oil can still escape from the bearing chamber through these devices, and so they do not solve the fundamental problem.
- Any oil that does leak out of a bearing chamber may contaminate the core air flow of the engine. When gas turbine engines are installed in aircraft, typically a proportion of the core air flow is taken to supply breathable air for the crew and passengers. The “cabin odour” arising out of this sort of contamination has long been recognised as undesirable. However, in recent years it has become increasingly clear that contaminated cabin air may also represent a serious health and safety hazard.
- It is therefore an object of the present invention to provide a simple and compact vent, which will allow air to flow both into and out of the bearing chamber, but which will substantially prevent the leakage of oil from the bearing chamber.
- According to one aspect of this invention, a vent for a fluid system includes a chamber through which fluid can flow along either a first flow path or a second flow path, in which the resistance to fluid flow is relatively high when the fluid follows the first flow path and the resistance to fluid flow is relatively low when the fluid follows the second flow path.
- Preferably the first flow path is associated with fluid flow in one direction through the chamber, and the second flow path is associated with fluid flow in the opposite direction through the chamber.
- Preferably the chamber has two ports, the two ports lying in planes substantially perpendicular to each other.
- In a particular preferred embodiment of this aspect of the invention, the chamber is substantially cylindrical. Preferably, one of the two ports is arranged to be substantially coaxial with the chamber and the other of the two ports is arranged to be substantially tangential to the chamber.
- The substantially tangential port may have a convergent or convergent-divergent inner profile.
- An annular wall member may protrude generally axially from the coaxial port into the chamber.
- The fluid flow, at least when following the first flow path, may include a component of higher density than the fluid, and the flow of the fluid along the first flow path may act to separate the higher density component from the fluid. The chamber may be extended in an axial direction to receive the higher density component separated from the fluid. Means may be provided to carry the higher density component out of the chamber.
- The higher density component may comprise a lubricant.
- The vent may be a part of a bearing chamber. The vent may be a part of a gas turbine engine.
- According to an alternative aspect of the invention, a venting arrangement for a fluid system comprises a first vent and a second vent, the first and second vents being arranged in flow series, in which the first and second vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of the first vent, and when fluid flows through the venting arrangement in the other, opposite direction it follows the first flow path through the chamber of the second vent.
- According to a further alternative aspect of the invention, a venting arrangement for a fluid system comprises a plurality of vents, the vents being arranged in flow series, in which the vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of each vent in succession, and when fluid flows through the venting arrangement in the other, opposite direction it follows the second flow path through the chamber of each vent in succession.
- The venting arrangement may be a part of a bearing chamber. The venting arrangement may be a part of a gas turbine engine.
- The preferred embodiments of all the aspects of the invention described in this specification use a device, known as a vortex throttle or vortex diode, which is well known in the art of fluidics. This device will be described in more detail later in the specification. Those skilled in the art of fluidics will be aware of the distinctions between a vortex throttle and a vortex diode; for the purposes of this specification such distinctions are generally unimportant and for the sake of clarity the term “vortex diode” will be used throughout.
- Fluidics is a discipline whose origins lie in attempts to overcome the susceptibility of electronic circuits to interference from electromagnetic radiation. It teaches the construction of circuits, analogous to electrical or electronic circuits, in which a flow of fluid, rather than a flow of electrons, performs the work. Devices such as switches, diodes, amplifiers and so on, familiar in an electrical context, can also be made to work satisfactorily in fluidic circuits. Fluidics has received relatively little attention in recent years, although its principles have been applied (on a larger scale) in fields such as sewage flow control, where the absence of moving parts in fluidic components permits the construction of reliable valves that are not prone to blockage.
- Certain embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
-
FIG. 1 is a schematic sectional view of a vortex diode of known type, showing the air flows in the “low resistance” direction; -
FIG. 2 is a schematic sectional view taken on the line A-A inFIG. 1 ; -
FIG. 3 is a schematic sectional view of a vortex diode of known type, showing the air flows in the “high resistance” direction; -
FIG. 4 is a schematic sectional view taken on the line B-B inFIG. 3 ; -
FIG. 5 is a schematic representation of a bearing chamber having a vent according to one aspect of the invention; -
FIGS. 6 and 7 are schematic sectional views of two alternative embodiments of a bearing chamber vent according to one aspect of the invention; -
FIG. 8 is a schematic sectional view of a further alternative embodiment of a bearing chamber vent according to one aspect of the invention; -
FIG. 9 is a schematic representation of a bearing chamber having a venting arrangement according to an alternative aspect of the invention; -
FIG. 10 is a schematic representation of a bearing chamber having a venting arrangement according to a further alternative aspect of the invention. - Referring first to
FIGS. 1 and 2 , avortex diode 20 of known type comprisesstructure 22 defining acylindrical volume 24. Two ducts of circular cross-section are in fluid communication with thecylindrical volume 24.Duct 26 is coaxial with thecylindrical volume 24 andduct 28 is tangential to thecylindrical volume 24. - When fluid flows into the
cylindrical volume 24 through theduct 26, as shown by thearrow 30 inFIG. 2 , it will tend to flow substantially in the manner indicated by thearrows 32 so as to exit thecylindrical volume 24 via theduct 28, and the resistance to flow will be relatively low. - Referring now to
FIGS. 3 and 4 , the arrangement of thevortex diode 20 is exactly as inFIGS. 1 and 2 . When fluid flows into thecylindrical volume 24 through theduct 28, as shown by thearrows 40, the geometry of thecylindrical volume 24 will tend to urge the fluid into vortical flow, as shown by thearrow 42 inFIG. 3 . The fluid will then exit thecylindrical volume 24 via the duct 26 (as shown by thearrow 44 inFIG. 4 ), but because of the swirling motion imparted to the flowing fluid the resistance to flow will be relatively high. Furthermore, any higher density component entrained in the fluid will tend to be urged outwards by centrifugal force, and will tend to be separated from the fluid. - The
duct 28 may have an inner profile that converges towards thecylindrical volume 24, or may have an inner profile that is convergent-divergent. When fluid flows into thecylindrical volume 24 through theduct 28, as shown inFIGS. 3 and 4 , such an inner profile will increase the velocity of the fluid flowing into thecylindrical volume 24, for a given pressure drop, and thus increase the efficiency of the separation. -
FIG. 5 shows a schematic sectional view of abearing chamber 50 of a gas turbine engine (not shown) having a vent according to one aspect of the invention.Conduit 52 links thebearing chamber 50 to thetangential port 54 of avortex diode 56 of known type.Conduit 58 links thecoaxial port 60 of thevortex diode 56 to aregion 62 outside thebearing chamber 50. - The vent is shown attached to the side of the bearing chamber. However, it is envisaged that it could equally well be integrated into the structure of the bearing chamber, or alternatively be entirely separate from the bearing chamber and mounted separately within the engine.
- In normal operation, the pressure in the bearing
chamber 50 will be lower than the pressure in theregion 62 outside the bearingchamber 50, and so there will be a flow of air from theregion 62 into the bearingchamber 50. Air will therefore flow into thevortex diode 56 through thecoaxial port 60, and out through thetangential port 54. The air flow through thevortex diode 56 will therefore be substantially as shown by thearrows FIGS. 1 and 2 , and the resistance to flow will be relatively low. - It is possible, under certain operating conditions of the gas turbine engine, that the relative pressures in the engine may change such that the pressure in the bearing
chamber 50 is higher than the pressure in theregion 62. There will then be a flow of air from the bearingchamber 50 into theregion 62. Air will therefore flow into thevortex diode 56 through thetangential port 54, and out through thecoaxial port 60. The air flow through thevortex diode 56 will therefore be substantially as shown by thearrows FIGS. 3 and 4 , and the resistance to flow will be relatively high. It is likely that some oil or similar lubricant will be entrained in the air flow, and (as explained in the discussion ofFIGS. 3 and 4 ) the swirling motion imparted to the air will tend to urge any such component outwards by centrifugal force, and will thus tend to separate it from the air. -
FIGS. 6 and 7 show two alternative embodiments of the vortex diode used in the vent ofFIG. 5 , in which provision is made to collect oil separated out from the air flow. In the embodiment ofFIG. 6 thecylindrical volume 24 is extended downward by the addition of anannular volume 64. InFIG. 7 , the whole of thecylindrical volume 24 is enlarged downward. In use, under the abnormal conditions described earlier when the air flow is as shown inFIGS. 3 and 4 , any oil separated out from the air flow will collect in the annular volume 64 (ofFIG. 6 ) or in the lower part of the enlarged cylindrical volume 24 (ofFIG. 7 ). Subsequently, when the air flow returns to normal, as shown inFIGS. 1 and 2 , the separated oil can flow through theconduit 66 back into theduct 28 and subsequently back to the bearing chamber, impelled by the normal flow of air out of thevortex diode 20 through the duct 28 (as shown byarrow 32 inFIG. 1 ). Theconduits -
FIG. 8 shows an alternative embodiment of a vortex diode having a higher resistance to flow in the “low resistance” direction. Anannular collar 68 protrudes into thecylindrical volume 24. In addition, theduct 28 is of smaller diameter than in the vortex diode ofFIG. 1 . It will be appreciated, by one skilled in the art, that changes may be made to the protrusion of thecollar 68, and to the diameters of the twoducts -
FIG. 9 shows a bearing chamber having a venting arrangement according to an alternative aspect of the invention, which comprises two vortex diodes in flow series.Conduit 52 links the bearingchamber 50 to thetangential port 70 of afirst vortex diode 72.Conduit 74 links thecoaxial port 76 of thefirst vortex diode 72 to thecoaxial port 78 of asecond vortex diode 80.Conduit 82 links thetangential port 84 of thesecond vortex diode 80 to aregion 62 outside the bearingchamber 50. - In normal operation, when the pressure in the bearing
chamber 50 is lower than the pressure in theregion 62, there will be a flow of air from theregion 62 into the bearingchamber 50. Air will therefore flow into thesecond vortex diode 80 via itstangential port 84, and out through itscoaxial port 78. It will be apparent that the air flow through thesecond vortex diode 80 will therefore be substantially as shown by thearrows FIGS. 3 and 4 , and that the resistance to flow will be relatively high. Furthermore, any oil entrained in the air flow will tend to be separated out by centrifugal force. The air will subsequently flow through theconduit 74 and through thefirst vortex diode 72, entering through thecoaxial port 76 and exiting through thetangential port 70. The air flow through thefirst vortex diode 72 will therefore be substantially as shown byarrows FIGS. 1 and 2 , and the resistance to flow will be relatively low. - In the converse case, where the pressure in the bearing
chamber 50 is higher than the pressure in theregion 62, the flow of air will be from the bearingchamber 50 into theregion 62. It will be apparent that the flow of air through each of the first and second vortex diodes will be reversed. Consequently thefirst vortex diode 72 will now offer a relatively high resistance to flow, and any oil entrained in the air flow will tend to be separated out by centrifugal force; thesecond vortex diode 80 will offer a relatively low resistance to flow. Thus, this venting arrangement will offer a relatively high resistance to flow in both directions, while still permitting the centrifugal separation of any oil entrained in the air flow. - It will be appreciated, by one skilled in the art, that this arrangement could be further refined by tailoring the flow characteristics of the first and second vortex diodes (as discussed with reference to
FIG. 8 ) to obtain various combinations of flow characteristics in the two directions - The venting arrangement is shown attached to the side of the bearing chamber. However, it is envisaged that it could equally well be integrated into the structure of the bearing chamber, or alternatively be entirely separate from the bearing chamber and mounted elsewhere within the engine.
- It will be appreciated that the two vortex diodes may be arranged differently in relation to each other, provided that their coaxial ports are always linked together, without affecting the operation of the venting arrangement.
-
FIG. 10 shows a bearing chamber having a venting arrangement according to a further aspect of the invention, comprising three vortex diodes arranged in flow series. -
Conduit 52 links the bearingchamber 50 to thetangential port 54 of afirst vortex diode 56. Aconduit 57 links thecoaxial port 60 of thefirst vortex diode 56 to thetangential port 54 of asecond vortex diode 56. Afurther conduit 57 links thecoaxial port 60 of the second vortex diode to thetangential port 54 of athird vortex diode 56, in like manner.Conduit 58 links thecoaxial port 60 of thethird vortex diode 56 to aregion 62 outside the bearingchamber 50. - Under normal operating conditions, when the pressure within the bearing
chamber 50 is less than the pressure in theregion 62 outside the bearingchamber 50, air will flow from theregion 62, through theconduit 58, then successively through the threevortex diodes 56, entering each in turn through itscoaxial port 60 and exiting through itstangential port 54. Within eachvortex diode 56, then, the flow of air will be substantially as shown by thearrows FIGS. 1 and 2 , and the resistance to flow through eachvortex diode 56 will be relatively low. - In the converse case, when the pressure within the bearing
chamber 50 is greater than the pressure in theregion 62, air will flow out of the bearingchamber 50, through theconduit 52, then successively through the threevortex diodes 56, entering each in turn through itstangential port 54 and exiting through itscoaxial port 60. Within eachvortex diode 56, then, the flow of air will be substantially as shown by thearrows FIGS. 3 and 4 , and the resistance to flow will be relatively high. In addition, any oil entrained in the air flow can be separated out by centrifugal force in any of the three vortex diodes, thus giving a more effective separation than in the embodiment having only one vortex diode. - The venting arrangement is shown attached to the side of the bearing chamber. However, it is envisaged that it could equally well be integrated into the structure of the bearing chamber, or alternatively be entirely separate from the bearing chamber and mounted elsewhere within the engine.
- It will be appreciated that the three vortex diodes may be arranged differently in relation to each other, provided that the ports of the successive vortex diodes are always connected in the manner shown in
FIG. 10 , without affecting the operation of the venting arrangement. - Although this aspect of the invention has been described with reference to three vortex diodes, it will be appreciated by those skilled in the art that other numbers of vortex diodes could equally well be used.
- It will be appreciated that it would also be possible for each of the vortex diodes to have different flow characteristics (as discussed in connection with
FIG. 8 ), for example to optimize the oil separation.
Claims (20)
1. A vent for a fluid system, the vent including structure defining a chamber, the chamber defining a first flow path and a second flow path, in which fluid is able to flow through the chamber along either the first flow path or the second flow path, in which the resistance to fluid flow is relatively high when the fluid follows the first flow path and the resistance to fluid flow is relatively low when the fluid follows the second flow path.
2. A vent as claimed in claim 1 , in which the first flow path is associated with fluid flow in one direction through the chamber, and the second flow path is associated with fluid flow in the opposite direction through the chamber.
3. A vent as claimed in claim 1 , which further includes structure defining two ports, the two ports being in fluid communication with the chamber and lying in planes substantially perpendicular to each other.
4. A vent as claimed in claim 3 , in which the chamber is substantially cylindrical.
5. A vent as claimed in claim 4 , in which one of the two ports is substantially coaxial with the chamber and the other of the two ports is substantially tangential to the chamber.
6. A vent as claimed in claim 5 , in which the inner profile of the substantially tangential port is convergent.
7. A vent as claimed in claim 5 , in which the inner profile of the substantially tangential port is convergent-divergent.
8. A vent as claimed in claim 5 , in which an annular wall member protrudes generally axially from the coaxial port into the chamber.
9. A vent as claimed in claim 1 , in which the fluid flow at least when following the first flow path includes a component of higher density than the fluid and the flow of the fluid along the first flow path acts to separate the higher density component from the fluid.
10. A vent as claimed in claim 9 , in which the chamber is extended in an axial direction to receive the higher density component separated from the fluid.
11. A vent as claimed in claim 9 , in which means are provided to carry the higher density component out of the chamber.
12. A vent as claimed in claim 9 , in which the higher density component comprises a lubricant.
13. A bearing chamber including a vent as claimed in claim 1 .
14. A gas turbine engine including a vent as claimed in claim 1 .
15. A venting arrangement for a fluid system, comprising a first vent as claimed in claim 1 and a second vent as claimed in claim 1 , the first and second vents being arranged in flow series, in which the first and second vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of the first vent, and when fluid flows through the venting arrangement in the other, opposite direction it follows the first flow path through the chamber of the second vent.
16. A venting arrangement for a fluid system, comprising a plurality of vents as claimed in claim 1 , the vents being arranged in flow series, in which the vents are so arranged that when fluid flows through the venting arrangement in one direction it follows the first flow path through the chamber of each vent in succession, and when fluid flows through the venting arrangement in the other direction it follows the second flow path through the chamber of each vent in succession.
17. A bearing chamber including a venting arrangement as claimed in claim 15 .
18. A bearing chamber including a venting arrangement as claimed in claim 16 .
19. A gas turbine engine including a venting arrangement as claimed in claim 15 .
20. A gas turbine engine including a venting arrangement as claimed in claim 16.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/178,325 US20050279061A1 (en) | 2002-08-13 | 2005-07-12 | Vents for fluid systems |
US11/652,126 US7384439B2 (en) | 2002-08-13 | 2007-01-11 | Vents for fluid systems |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0218777A GB2391959B (en) | 2002-08-13 | 2002-08-13 | Vents for bearing chambers |
GB0218777.1 | 2002-08-13 | ||
US10/619,145 US20040031249A1 (en) | 2002-08-13 | 2003-07-15 | Vents for fluid systems |
US11/178,325 US20050279061A1 (en) | 2002-08-13 | 2005-07-12 | Vents for fluid systems |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/619,145 Continuation US20040031249A1 (en) | 2002-08-13 | 2003-07-15 | Vents for fluid systems |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/652,126 Continuation US7384439B2 (en) | 2002-08-13 | 2007-01-11 | Vents for fluid systems |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050279061A1 true US20050279061A1 (en) | 2005-12-22 |
Family
ID=9942202
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/619,145 Abandoned US20040031249A1 (en) | 2002-08-13 | 2003-07-15 | Vents for fluid systems |
US11/178,325 Abandoned US20050279061A1 (en) | 2002-08-13 | 2005-07-12 | Vents for fluid systems |
US11/652,126 Expired - Fee Related US7384439B2 (en) | 2002-08-13 | 2007-01-11 | Vents for fluid systems |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/619,145 Abandoned US20040031249A1 (en) | 2002-08-13 | 2003-07-15 | Vents for fluid systems |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/652,126 Expired - Fee Related US7384439B2 (en) | 2002-08-13 | 2007-01-11 | Vents for fluid systems |
Country Status (2)
Country | Link |
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US (3) | US20040031249A1 (en) |
GB (1) | GB2391959B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150306529A1 (en) * | 2014-04-24 | 2015-10-29 | Nitto Denko Corporation | Ventilation member |
US20150313034A1 (en) * | 2014-04-24 | 2015-10-29 | Nitto Denko Corporation | Ventilation member |
US9480376B1 (en) | 2012-04-16 | 2016-11-01 | Billy Goat Industries, Inc. | Debris-collecting apparatus |
US9642508B1 (en) | 2012-04-16 | 2017-05-09 | Billy Goat Indutries, Inc. | Debris-collecting apparatus and method of collecting debris |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
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GB0610357D0 (en) | 2006-05-25 | 2006-07-05 | Rolls Royce Plc | Loss reduction apparatus |
DE102007058953A1 (en) * | 2007-12-07 | 2009-06-10 | Rolls-Royce Deutschland Ltd & Co Kg | Bearing chamber pressure system |
US20100130944A1 (en) * | 2008-11-21 | 2010-05-27 | Music Douglas E | Flow control devices for ophthalmic surgery |
PL2766314T3 (en) | 2011-10-11 | 2019-10-31 | Council Scient Ind Res | Vortex diodes as effluent treatment devices |
US9725338B2 (en) | 2011-10-11 | 2017-08-08 | Council Of Scientific & Industrial Research | Apparatus and method for reduction in ammoniacal nitrogen from waste waters |
GB201316543D0 (en) * | 2013-09-18 | 2013-10-30 | Rolls Royce Plc | Vortex fluid flow device |
GB201412869D0 (en) | 2014-07-21 | 2014-09-03 | Rolls Royce Plc | Pressure controlled chamber |
GB201508220D0 (en) | 2015-05-14 | 2015-06-24 | Rolls Royce Plc | A drain for a pressure sensing line |
RU199491U1 (en) * | 2020-03-23 | 2020-09-03 | Иван Валерьевич Цветков | VORTEX DIODE |
RU199636U1 (en) * | 2020-05-06 | 2020-09-11 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Омский государственный технический университет"(ОмГТУ) | VORTEX DIODE OF INCREASED DIODE |
RU2740487C1 (en) * | 2020-06-09 | 2021-01-14 | Федеральное государственное бюджетное образовательное учреждение высшего образования "Омский государственный технический университет"(ОмГТУ) | Vortex hydropneumatic diode |
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JPS6113801Y2 (en) * | 1980-08-20 | 1986-04-28 | ||
GB2084266B (en) * | 1980-09-26 | 1984-12-19 | Rolls Royce | Oil system for aircraft gas turbine engine |
GB2108714B (en) * | 1981-10-30 | 1985-07-31 | Atomic Energy Authority Uk | Fluidic devices |
GB8908067D0 (en) * | 1989-04-11 | 1989-05-24 | Atomic Energy Authority Uk | A fluidic ventillation control system |
JPH09303130A (en) * | 1996-05-10 | 1997-11-25 | Kubota Corp | Engine with closed breather device |
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- 2002-08-13 GB GB0218777A patent/GB2391959B/en not_active Expired - Fee Related
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- 2003-07-15 US US10/619,145 patent/US20040031249A1/en not_active Abandoned
-
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- 2005-07-12 US US11/178,325 patent/US20050279061A1/en not_active Abandoned
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US4131134A (en) * | 1977-05-04 | 1978-12-26 | Owen, Wickersham & Erickson | Fluid flow regulator |
US4269607A (en) * | 1977-11-07 | 1981-05-26 | Walker Robert A | Air-oil separator and method of separation |
US4433539A (en) * | 1982-05-13 | 1984-02-28 | United Technologies Corporation | Means for controlling air scavenge pressure in the bearing compartment of gas turbines |
US5042998A (en) * | 1989-02-03 | 1991-08-27 | Beusen Gerardus L | Device for treating or mixing components in gas or liquid streams |
US5059226A (en) * | 1989-10-27 | 1991-10-22 | Sundstrand Corporation | Centrifugal two-phase flow distributor |
US6228151B1 (en) * | 1999-08-18 | 2001-05-08 | G.B.D. Corp. | Apparatus and method for separating particles from a cyclonic fluid flow |
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Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9480376B1 (en) | 2012-04-16 | 2016-11-01 | Billy Goat Industries, Inc. | Debris-collecting apparatus |
US9642508B1 (en) | 2012-04-16 | 2017-05-09 | Billy Goat Indutries, Inc. | Debris-collecting apparatus and method of collecting debris |
US10667465B1 (en) | 2012-04-16 | 2020-06-02 | Billy Goat Industries, Inc. | Debris-collecting apparatus and method of collecting debris |
US11690331B2 (en) | 2012-04-16 | 2023-07-04 | Briggs & Stratton, Llc | Debris-collecting apparatus and method of collecting debris |
US20150306529A1 (en) * | 2014-04-24 | 2015-10-29 | Nitto Denko Corporation | Ventilation member |
US20150313034A1 (en) * | 2014-04-24 | 2015-10-29 | Nitto Denko Corporation | Ventilation member |
US9242198B2 (en) * | 2014-04-24 | 2016-01-26 | Nitto Denko Corporation | Ventilation member |
US9332662B2 (en) * | 2014-04-24 | 2016-05-03 | Nitto Denko Corporation | Ventilation member |
Also Published As
Publication number | Publication date |
---|---|
US20040031249A1 (en) | 2004-02-19 |
GB2391959B (en) | 2006-01-04 |
US20070157587A1 (en) | 2007-07-12 |
US7384439B2 (en) | 2008-06-10 |
GB2391959A (en) | 2004-02-18 |
GB0218777D0 (en) | 2002-09-18 |
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