Seal for a joint or juncture – Seal between relatively movable parts – Close proximity seal
Reexamination Certificate
1999-04-12
2001-04-24
Melius, Terry Lee (Department: 3628)
Seal for a joint or juncture
Seal between relatively movable parts
Close proximity seal
C277S378000
Reexamination Certificate
active
06220602
ABSTRACT:
THE FIELD OF THE INVENTION
The present invention relates to a seal arrangement and in particular to a seal arrangement between relatively movable components.
BACKGROUND OF THE INVENTION
It is frequently necessary to effect a seal in a clearance gap between two components that are capable of relative movement. In particular one or more seals are often required to seal between a rotatable shaft and a static component containing the shaft, the static structure having a bore through which the shaft extends. A gas turbine engine has shafts which rotate at relatively high speeds and which are exposed to pressurised hot gases. Seals are required between the shafts and a surrounding static structure. Also a gas turbine engine has rotor discs, or drums, which rotate at relatively high speeds and which carry the rotor blades. Seals are required between the radial tips of the rotor blades and a surrounding static structure and seals are required between the rotor disc, or drum, and the static structure. The seal performance may have a significant effect on the overall efficiency of the gas turbine engine.
In gas turbine engines it is known to control the clearance between the rotor blade tips and the static structure by using materials with different coefficients of thermal expansion, by controlled heating or cooling the static structure surrounding the rotor blades, by the controlled supply of pressurised gas to a chamber to move the static structure or by using abradable seals.
In gas turbine engines it is known to use seals between the rotor disc, or drum, and the static structure for example labyrinth seals, abradable seals etc.
In gas turbine engines it is known to use seals between the shaft and the static structure for example labyrinth seals, brush seals, leaf seals and air riding seals etc.
Labyrinth seals, abradable seals, leaf seals and brush seals are passive seals whereas the controlled heating and the controlled pressurising of the static structure are active seals.
In most gas turbine engines labyrinth seals are used and these are designed to avoid large clearances at certain operating conditions, however their sealing is not as good as required and hence the specific fuel consumption is not good. The active seals have the potential to give increased sealing with a resultant improvement in the specific fuel consumption of the gas turbine engine but they are not generally used because they are complex systems.
Any improvement in the seals may improve the specific fuel consumption of the gas turbine engine.
SUMMARY OF THE INVENTION
The present invention seeks to provide a novel seal arrangement which has improved sealing efficiency.
Accordingly the present invention provides a seal arrangement between relatively movable components, the seal comprising at least one magnet on a first one of the components and at least one magnet or at least one electrically conducting member on the second component, a clearance being defined between the first component and the second component, means to bias the at least one magnet on the first component and the at least one magnet or electrically conducting member on the second component towards each other to reduce the clearance, and the at least one magnet on the first component and the at least one magnet or electrically conducting member on the second component being arranged to produce a force to act against the biasing means to control the clearance.
The first and second components may be relatively rotatable. The first component may be a static component and the second component may be a rotatable component.
The first component may comprise a stator casing and a plurality of stator vanes extending radially inwardly from the stator casing, the second component comprises a rotor carrying a plurality of rotor blades, a plurality of circumferentially arranged magnets on the radially inner ends of the stator vanes, at least one magnet or at least one electrically conducting member on the rotor and means to bias the stator vanes radially inwardly towards the rotor.
The rotor may have at least one annular magnet or at least one set of circumferentially arranged magnets. The rotor may have at least one annular electrically conducting member.
The first component may comprise a stator structure, the second component comprises a rotor carrying a plurality of rotor blades, at least one magnet on the stator structure, at least one magnet or at least one electrically conducting member on the rotor and means to bias the at least one magnet on the stator axially towards the rotor.
The stator structure may have at least one annular magnet.
The first component may a rotatable component and the second component may be a static component.
The first component may be a rotor carrying a plurality of rotor blades, the second component is a stator casing, each rotor blade having a magnet at its tip, the casing having a portion surrounding the blade tips, the casing portion is biased radially towards the blade tips, the casing portion comprising at least one electrically conducting member or a plurality of magnets.
The rotor may be a compressor rotor, a turbine rotor or a fan rotor.
The static component may carry a plurality of radially inwardly extending and tangentially inclined magnetic members, the rotatable component has at least one magnet or at least one electrically conducting member spaced radially from the radially inner ends of the magnetic members.
The radially inwardly extending and tangentially inclined magnetic members may be bristles or leaves.
The means to bias may comprise a supply of pressurised fluid or it may comprise spring means.
The at least one magnet on the first component may be a permanent magnet, an electromagnet or a superconducting magnet. The at least one magnet on the second component may be a permanent magnet, an electromagnet or a superconducting magnet.
There may be means to measure the clearance and means to adjust the biasing means in response to the clearance measurement to control the clearance.
The clearance may be defined between the at least one magnet on the first component and the at least one magnet or the electrically conducting member on the second component.
The clearance may be defined between a sub component attached to the at least one magnet on the first component and a sub component attached to the at least one magnet or the electrically conducting member on the second component.
REFERENCES:
patent: 2883212 (1959-04-01), Laser
patent: 3869135 (1975-03-01), Diederich
patent: 4434987 (1984-03-01), Albers et al.
patent: 4447063 (1984-05-01), Kotzur et al.
patent: 4600202 (1986-07-01), Schaeffler et al.
patent: 4795168 (1989-01-01), Adams et al.
patent: 5064205 (1991-11-01), Whitford
patent: 5161804 (1992-11-01), Orlowski et al.
patent: 5865441 (1999-02-01), Orlowski
patent: 0458547 A2 (1981-11-01), None
patent: 2087986 (1982-06-01), None
patent: 2258699 (1993-02-01), None
patent: WO23298 (1995-08-01), None
Knott David S
Webster John R
Hewitt James M.
Manelli, Denison & Selte PLLC
Melius Terry Lee
Rolls-Royce plc
Taltavull W. Warren
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