Rotary kinetic fluid motors or pumps – With passage in blade – vane – shaft or rotary distributor...
Reexamination Certificate
2002-10-15
2004-07-27
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With passage in blade, vane, shaft or rotary distributor...
C415S142000, C415S170100
Reexamination Certificate
active
06767182
ABSTRACT:
This application is the US national phase of international application PCT/IB01/01297 filed May 15, 2001, which designated the US.
The present invention relates to a device for controlling the cooling flows of gas turbines.
As is known, gas turbines comprise a compressor, to which air is fed from the external environment so as to bring it up to pressure.
The air under pressure passes into a series of combustion chambers which terminate in a nozzle and into each of which an injector feeds fuel which is mixed with the air so as to form a combustible air mixture to be burned.
The turbine converts the enthalpy of the gases combusted in the aforementioned combustion chamber into mechanical energy available for a user.
The present invention refers, in particular, to the outlet zone of the gas turbine compressor.
By way of introduction of the technical problems solved by the present invention, it should be noted that the constant attempt to increase the efficiency of gas turbines is subject to the requirement for optimisation of all the flows inside the turbine engines.
In particular, the air supplied from the compression stages, since it has been produced with considerable expenditure in terms of the thermodynamic cycle, must be used as far as possible for combustion, instead of for cooling or confining functions which moreover are required in the most critical hot zones.
The problem which is posed in this context is therefore that of correct metering of this air in the various zones, taking into account that the amount of air required is variable depending on the operating conditions, the age and the degree of wear or soiling of the turbine engine, its components and the dimensional variations of the components during the transients.
In fact, in the event of an insufficient air flow, the consequences are, at best, a significant reduction in the life of the components with the possibility of blade failure and fires.
It is pointed out here, incidentally, that these factors may have a negative effect resulting in an increase in costs for users.
In order to understand more fully the technical problems involved in the present invention, reference should be made first of all to
FIGS. 1
to
3
, which show, respectively: a cross-sectional view of a gas turbine according to the prior art, denoted overall by the reference number
20
; an enlarged view of the outlet zone of the compressor
21
of the gas turbine
20
; and the conventional solution for controlling the cooling flows of the gas turbine
20
which may envisage fixed bores
22
in the body
50
of the inner barrel
23
.
In greater detail,
FIG. 1
shows a gas turbine
20
provided with a compressor
21
with which an inner barrel
23
and a load-bearing bolster
24
are associated;
FIG. 1
also shows, among other things, the rotors
25
and
26
of the turbine
20
.
Examining in greater detail
FIG. 2
, it is possible to see the casing
27
and the blades
28
, forming part of the compressor
21
, the outlet diffuser
29
of the compressor
21
, the venting outlet
33
of the load-bearing bolster
24
and the air seals
30
and
31
of the inner barrel
23
;
FIG. 2
also shows a portion of the rotor
32
.
The solutions currently used for correct metering of the air flows intended for cooling and sealing consist in the specific definition of orifices on the supply tubes/ducts and determination of the degree of play between rotating members and labyrinths formed in complementary stator components.
Orifices and labyrinths (see
FIG. 3
) are therefore interdependent from a design point of view and precisely determined during finalisation of the prototype, so that extreme situations and deviations in design can be safely handled.
This means that these adjustments and tolerances are therefore defined by the manufacturer during assembly.
However, the need for an increase in the efficiency of the machines on the part of customers has resulted in a reduction in the air flows to the absolute minimum necessary, with the application of seals which are increasingly efficient—often excessively so—with the serious risks mentioned above.
In particular, there has been a tendency to reduce the amount of air which escapes from the compressor
21
towards the innermost portions of the machine
20
(FIGS.
1
-
2
), in particular in the zone located inside the inner barrel
22
.
This air, passing through a first barrier of labyrinth seals, then escapes from the vent of the load-bearing bolster
24
of the compressor
21
and through the front interspace of the first turbine rotor, through the labyrinth formed with the angel wings on the shanks of the blades and the stationary seals mounted on the casing.
The function of this air is therefore that of providing a seal from the oil vapours in the bolster
24
and hot gases inside the turbine
20
, cooling the turbine disk and removing the heat produced by means of ventilation friction inside the inner barrel
23
.
Experience has shown that often, the compromise adopted between the need for an increase in efficiency and reliability of the machine, since there is no possibility for adjustment, has resulted in a sudden reduction in reliability of the machine.
An object of the present invention is therefore to provide a device for controlling the cooling flows of gas turbines which is able to allow the possibility of varying the air flow entering into the inner barrel, without the need for replacement of the latter.
More particularly, the invention aims to avoid any kind of disassembly of the most important components of the turbine engine, while allowing variation in the air flow into the inner barrel.
Another object of the invention is to provide a device for controlling the cooling flows of the gas turbines which allows adjustment which is customized and repeatable over time, by simply stopping the machine and performing simple operations involving the selection and replacement of suitable component parts.
A further final object of the invention is to provide a device for controlling the cooling flows of gas turbines which is advantageous from a cost point of view.
Last but not least, an object of the invention is to provide a device for controlling the cooling flows of gas turbines which is substantially safe and reliable.
These and other objects are achieved by a device for controlling the cooling flows of gas turbines, where the aforementioned gas turbine is provided with a compressor with which an inner barrel and a load-bearing bolster are associated, characterized in that it envisages the arrangement of a plurality of replaceable nozzles which have an internal bore with different diameters and which can be mounted in suitable holes formed in the substantially cylindrical body of the aforementioned inner barrel so as to allow a variation in the flow of air entering into the aforementioned inner barrel, by means of the selection and replacement of at least some of the aforementioned nozzles with other nozzles having an internal bore with suitable diameters.
According to a preferred embodiment of the present invention, each of the aforementioned nozzles has a threaded section able to engage with a corresponding internally threaded section present in a hole formed in the aforementioned inner barrel.
According to a further preferred embodiment of the present invention, each replaceable nozzle has a cylindrical section with a diameter smaller than that of the threaded section and a pair of incisions for engagement with a magnetic-head spanner.
According to another preferred-embodiment of the present invention, the nozzles are inserted by means of a guide tube and a magnetic-head spanner, the guide tube being inserted inside a corresponding hole present in the casing of the aforementioned compressor.
More particularly, the guide tube has a threaded collar for allowing engagement thereof with a corresponding hole present in the casing of the compressor.
The guide tube is inserted into the hole of the compressor casing by sliding it until the aforementioned threaded collar thereof is screwed into the cor
Look Edward K.
McAleenan James M
Nixon & Vanderhye PC
Nuovo Pignone Holding S.p.A.
LandOfFree
Device for controlling the cooling flows of gas turbines does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for controlling the cooling flows of gas turbines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for controlling the cooling flows of gas turbines will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3192066