|Title of Invention||
A METHOD OF MAKING A MULTISTAGE SEAL
|Abstract||This invention relates to a method of making a multistage seal (10) comprising: specifying initial first and second brush seals (20,22) having common designs for collectively sealing a differential pressure (P1-P2) along a land (12) subject to relative rotation with said seals (20,22); modifying a common design feature of said seals (20,22) to share loading from said differential pressure without blowdown therefrom; modifying said seals (20,22) to ensure rotational stability with said land; determining pressure blowdown of said seals (20,22) under pressure. The following step of using information obtained from determining pressure blowdown of said seals (20,22) under pressure for modifying said common design feature of said seals (20,22) to substantially equally share said pressure loading under said blowdown.|
|Full Text||BACKGROUND OF THE INVENTION
The present invention relates generally to rotating seals, and, more specifically, to
multistage brush seals.
Various forms of engines or motors include various forms of seals therein specifically
configured for separating relatively high and low pressure regions thereof For example,
gas and steam turbine engines have various stages therein in which air, combustion
gases, and steam travel downstream with changes of pressure and temperature thereof.
Turbine engines are made as large as practical for maximizing output work and
performance efficiency. Large turbines also have correspondingly large pressure drops
of the fluid flow therethrough which requires suitable sealing during operatioa
In a labyrinth seal, a row of annular seal teeth is disposed closely adjacent to a
cooperating land for relative rotation therewith, with a radial clearance therebetween for
reducing the likelihood of undesirable rubbing therebetween. Another form of seal
typically found in turbine engines is the brush seal in which a pack of bristles is mounted
between supporting plates, with the distal ends of the bristles extending freely therefrom
for effecting a rotary seal with the adjacent land. The bristles are inclined from the land
and may form a small clearance therewith or may be in interference contact therewith
Brush seals offer the ability to effectively seal the very high pressures in a turbine
engine, for example, while maintaining stability during relative rotation with the land
and having a suitably long life during operation.
Experience has shown that a single stage brush seal has a practical limit of sealing
differential pressure up to about 400 psid, with a suitable safety factor for
correspondingly reducing that limit. Over-pressurization of the brush seal will cause
excessive leakage, plastic deformation thereof or fatigue failure in short time.
Brush seals may be disposed in series, but again experience has shown that their ability
to seal very high differential pressures in excess of 400 psid is again limited to
substantially less than twice the 400 psid limit, correspondingly reduced by the safety
factor, for each seal in view of the practical variation in load sharing therebetweea And,
experience has additionally shown that additional series brush seals in excess of two
have no practical capability of sealing increased differential pressure imposed across
those multiple stage brush seals.
In two or more stages of identical brush seals, the first stage is capable of sharing a
minority of the total pressure load across the brush seal assembly, with the last brush seal
carrying a majority of the total pressure loading. Accordingly, the sealing capability of
the multistage brush seals is limited by that last stage, and correspondingly limits the
maximum differential pressure which the seals may safely carry during operation.
It is known to vary the seal clearances with the adjacent land to vary the load sharing
capability of each seal stage. However, the specific value of the seal clearance affects
the total sealing capability, with larger clearances decreasing loading capability, while
smaller clearances increase loading capability.
However, small clearances subject the bristles to increased friction rubbing with the land
during transient operation of the engine, with friction rubbing correspondingly heating
the components. In a typical example, the land is defined by the outer perimeter of a
rotary shaft, and the brush seals are stationary. Friction rubbing of the bristles with the
shaft causes local heating thereof and corresponding thermal expansion which can
adversely affect stability of the rotating shaft. As the shaft thermally expands under
rubbing, the rubbing friction forces further increase for further increasing friction heating
of a shaft. And, the shaft is subject to undesirable instability, such as wobbling, which
can require emergency shut down of the entire engine.
The geometric configuration of the bristles also affects the maximum sealing capability
thereof Soft or flexible bristles are subject to increased bending under differential
pressure, and hard or stiff bristles increase the friction heating under rubbing with the
land. Furthermore, the differential pressure exerted across the pack of bristles effects
blowdown therein in which the inclined bristles deflect slightly radially inwardly, which
correspondingly increases friction heating during rubbing with the land.
In view of these interrelated operation effects of brush seals, conventionally known
multistage brush seals are limited to two brush seals in series, with a current practical
limit of 550 psid total differential pressure based on a suitable factor of safety therein.
And, the ability to achieve load sharing between the multiple seals stages is limited by
bristle rubbing and rotor stability.
Accordingly, it is desired to provide an improved multistage brush seal for increasing the
maximum load carrying capability thereof.
BRIEF DESCRIPTION OF THE INVENTION
Multistage brush seals are made by initially specifying designs thereof for collectively
sharing a differential pressure along an adjacent land subject to relative rotation with the
seals. The seals are modified to share the loading without blowdown therefrom. The
seals are further modified to ensure rotational stability with the land. The seals are built
and tested under pressure to determine pressure blowdown thereof And then, the seals
are again modified to share the pressure loading under blowdown. In this way, the seals
share the load in situ under the effects of blowdown.
BRIEF DESCRIPTION OF THE/DRAWINGS
The invention, in accordance with preferred and exemplary embodiments, together with
further objects and advantages thereof, is more particularly described in the following
detailed description taken in conjunction with the accompanying drawings in which:
Figure 1 is a partly sectional axial view through a portion of a multistage brush seal
adjacent a cooperating land in accordance with an exemplary embodiment of the present
Figure 2 is a partly sectional radial view of a portion of the multistage seal illustrated in
Figure 1 and taken along line 2-2.
Figure 3 is a flowchart representation of a method of making the multistage seal
illustrated in Figures 1 and 2 in accordance with an exemplary embodiment of the
DETAILED DESCRIPTION OF THE INVENTION
Illustrated in cross section in Figure I is a multistage annular seal 10 disposed
concentrically around an annular land 12 in the exemplary form of a rotor shaft. The
seal is suitably mounted in an annular seal support 14 coaxially about an axial or
longitudinal centerline axis 16 of the rotor shaft.
The seal is configured in Figure 1 for use in large industrial gas or steam turbine engines,
with the seal being a stationary or stator component surrounding the rotating shaft.
Alternatively, the land 12 may be stationary, with the seal being mounted for rotary
movement relative thereto.
In either configuration, the seal and land experience relative rotation during operation in
the engine, and the seal is configured for sealing differential pressure maintained on
opposite axial sides of the seal. For example, a fluid 18, such as steam, is maintained on
the right side of the seal at a high pressure P1 and is effectively sealed by the multistage
seal for rninimizing leakage between the seal and land to the region on the left side of the
seal maintained under a lower pressure P2.
The differential pressure, P1-P2, acting across the seal during operation may be
relatively high, and greater than about 400 psid for example, and may be substantially
higher than about the 550 psid which is the currently known maximum differential
pressure capability of conventional brush seals of two or more stages, with a safety
factor of two. As indicated above, conventional brush seals do not have the capability
for sealing such very high pressures without increased risk of damage to the seals or
The multistage seal illustrated in Figure 1 includes first and second annular brush seals
20,22 sharing a common design. Each brush seal includes an annular pack or multitude
of bristles 24a,b mounted axially between an annular forward support plate 26a,b and an
annular aft backing plate 28a,b.
The proximal or base ends of the first and second bristles 24a,b are suitably joined to the
corresponding base ends of the respective first and second forward and aft plates by
corresponding welds 30 in a conventional manner.
The individual brush seals 20,22 have a common design which is conventional, except as
modified in accordance with the present invention as further described hereinbetow. For
example, the distal ends of the bristles extend in free length Al,2 from the base ends of
the bristles laminated between the mounting plates to extend in cantilever fashion from
the distal ends of the corresponding aft plates 28a,b to define corresponding radial
clearances B1,2 with the adjacent land 12.
The bristle packs extend past the full radial length of the annular aft plates 28a,b, and
extend radially inwardly therefrom in the exemplary embodiment illustrated in Figure 1.
The radially inward extension of the distal ends of the bristles from the corresponding
distal ends of the aft plates defines a corresponding fence height C1,2.
Correspondingly, the cooperating forward plates 26a,b have recesses radially outwardly
from their radially inner distal ends which provide an axial gap with the bristles for
defining the corresponding free lengths A1,2 thereof. In the embodiment illustrated in
Figure 1, the two stages of brush seals are spaced axially apart by an axial spacing D
measured between the packs of bristles thereof.
Accordingly, during operation the high pressure fluid 18 is contained at the first forward
plate 26a of the first brush seal 20 and is effectively sealed by the first pack of bristles
24a with a correspondingly small radial clearance Bl which permits unobstructed
rotation of the shaft therein. However, some of the fluid 18 leaks through the first
bristles 24a and first clearance Bl and flows downstream to the second brush seal 22.
This lower pressure fluid is then sealed by the second pack of bristles 24b, with the small
radial second clearance B2 around the shaft. And, some of this lower pressure fluid
leaks through the second bristles 24b and second clearance B2 into the low pressure
region maintained near the face of the second aft plate 28b.
As shown in Figure 2, the second bristles 24b, as well as the first bristles 24a illustrated
in Figure 1, are tangentially inclined between their corresponding mounting plates at an
inclination angle of about 45-60 degrees from the tangential. The direction of rotation of
the shaft land 12 is illustrated counterclockwise in Figure 2, and the bristles are inclined
oppositely therefrom so that they may bend or flex radially outwardly under occasional
friction rubbing therebetween.
The individual bristles 24a,b may be formed of any conventional material, such as alloy
steel, with a relatively small diameter measured in a few mils. The material composition
of the bristles, length, diameter, and inclination angle affect the resulting bending
stiffness thereof during a rub with the shaft land 12.
As indicated above, the two-stage brush seals 20,22 could be identically configured for
sharing the pressure loading from the differential pressure P1-P2, but a conventional
configuration thereof is not capable of withstanding high differential pressure exceeding
about 550 psid. The bristles in such a conventional design would be relatively stiff and
would increase heating of the shaft during rubbing with the bristles and could lead to
shaft instability, including wobbling thereof.
However, in accordance with the present invention, the two brush seals 20,22 may be
suitably modified for substantially increasing their collective load carrying capability
without adversely affecting rotor stability due to occasional bristle-land rubbing.
More specifically, Figure 3 illustrates in flowchart form an exemplary embodiment of
making the multistage seal 10 illustrated in Figures 1 and 2 in a configuration having
increased load carrying capability while also enjoying rotor stability. The method
commences with the conventional boundary or engine conditions which define the
environment in which the multistage seal is intended to be used. For example, the
boundary conditions include the high and low pressures P1,2, the corresponding
differential pressure therebetween, the temperature of the fluid 18, the rotational speed of
the shaft, the overall geometry between the shaft 12 and the seal including radial
dimensions thereof and expected differential thermal growth between the stator and
rotor components of the seal including startup closures between the bristles and land.
The initial configurations of the two brush seals 20,22 are specified in any conventional
manner for maximizing their individual toad carrying capability under the expected high
pressure loads of operatioa The corresponding initial seal designs will therefore have
maximum bending stiffness of the inclined bristles for withstanding corresponding
maximum pressure loading thereof.
In the exemplary embodiment of the seals illustrated in Figures 1 and 2, the bristles are
initially designed with a suitable clearance B1,B2 with the rotating land 12 for nominal
operation therewith. Since the seal components are subject to differential thermal
expansion relative to the shaft, the initially selected seal clearances are cut-back or
enlarged for minimizing contact with the rotor land 12 and minimizing corresponding
heat generated thereby. It is noted that larger radial clearances decrease sealing
performance and also decrease efficiency of the engine.
A two-dimensional (2-D) computational flow model is suitably defined in corresponding
software, and analyzed in a conventional digitally programmable computer 32 illustrated
schematically in Figure 3 for determining or setting the radial clearances B1,2 of the two
seals for sharing pressure loading therebetween, preferably equally, without
consideration of blowdown. At this stage in the process, the design of the multistage
seal is conventional and is conducted without consideration of blowdown which would
occur in the in situ operation of the seal in its actual environment. The 2-D flow
modeling software is conventional, such as Design Flow Solutions which is
commercially available from ABZ, Inc., Chantilly, VA.
By adjusting the corresponding radial clearances B1 ,2, pressure loading may be shared
equally between the two seals, but this is an analytical-only prediction of the seal
performance without regard to blowdown. In practice, blowdown significantly affects
performance of the multistage seal including the load sharing between the discrete brush
The multistage seal is only as strong as its weakest seal The failure of any one of the
two brush seals therein will promptly cause the other brush seal to fail; and, therefore,
conventional two-stage brush seals are designed with suitable safety factors of operation,
and have corresponding limits on pressure loading capability as indicated above.
A suitable safety factor may be conventionally introduced into the design of the
multistage seal by setting the corresponding fence heights Cl,2 and corresponding
thicknesses E1 ,2, see figure 1, ofthe first and second packs of bristles 24a,b according to
the loading predicted by the 2-D model with a suitable safety factor of about two (2) for
Blowdown is a significant operational parameter of the seal in its intended environment
and is illustrated schematically in Figure 2. As the pressurized fluid 18 passes between
the individual bristles 24a,b of the both packs, the bristles are elastically bent or
displaced radially inwardly as shown in phantom line which decreases the effective
clearance between the distal ends thereof and the land 12. This radially inward
deflection ofthe bristles under pressure is expressed in a few mils or millimeters in view
of its small magnitude and represents the blowdown effect during operation under
Since blowdown affects bristle clearance with the land 12, blowdown also affects rotor
stability. Accordingly, conventional computational flow dynamics (CFD) may be used
to validate the load sharing distributions predicted in the 2-D model, and additionally
provide seal stability parameters associated with operation with the rotating shaft. The
CFD analysis is conducted in three dimensions (3-D) in the same or different digitally
programmable computer 32. The CFD software is conventional, such as STAR-CD
which is commercially available from CD-adapco, Melville, NY.
Using the 3-D analysis, the initial design of the two seals may be further modified in
order to satisfy suitable stability criteria for ensuring stable operation of the rotor
components without unacceptable wobbling, for example. Preferably, the 3-D analysis
is used to specify the free length Al,2 of the two bristle packs, the axial spacing D
therebetween, and the resulting bending stiffness of the bristles.
The 3-D analysis may also be used for optimizing the free length, axial spacing, and
additionally the seal clearances B1,2 to minimize heat generation under land rubbing
with the bristles while maintaining suitable stability.
The method of making the multistage seal disclosed above is preferably conducted
analytically in sequence to specify suitable designs thereof for sharing load substantially
equally therebetween while maintaining rotor stability. However, in situ operation of the
so-designed multistage seal will experience the practical variations in performance
which cannot be fully predicted analytically.
Accordingly, the multistage seal so analytically designed is then actually built and tested
in suitable size or scale for empirically determining its performance in its intended, or in
In testing of the multistage seal, pressures, temperatures, and mass flows are measured
between the high and low pressure sides of the seal to find or determine the blowdown of
each seal. The same 2-D flow model disclosed above may be used in a conventional
manner to determine the blowdown of each seal based on the measured performance
The 2-D flow model may then be used again to reset the radial clearances B 1,2 for each
of the seals to share the pressure loading substantially equally under the effects of the
measured blowdown. Engineering judgment or trial and error may be used for
increasing or decreasing the respective sizes of the two clearances B 1,2 in conjunction
with the corresponding measured blowdowns thereof for equally sharing the pressure
In this way, the multistage seal may be initially analytically designed in a conventional
manner without blowdown affects, then optimized for stability of operation in situ, and
then built and tested for measuring seal performance and behavior. The empirical data
from the testing is then used to determine blowdown under differential pressure, and the
sea! designs may be further modified for equally sharing the load while using the
measured blowdown and achieving stable operation
This method of making the multistage sea! results in two brush seals which may be
otherwise identical in design and configuration, except as required for sharing the
pressure loading substantially equally in situ while maintaining rotor stability. In this
way, the two brush seals may be designed for more accurately sharing the pressure
loading equally, which correspondingly increases their collective ability for safely
sharing the total differential pressure acting across the multistage seal. Relatively minor,
but significant, variation in the geometry of the two brush seals, can achieve a substantial
increase in the differential pressure capability thereof, which may be reliably obtained in
situ in the intended environment notwithstanding the affects of blowdown.
Furthermore, the method may be further used to introduce three or more stages of brush
seals and accurately control the load sharing therebetween including the affects of
blowdown at each of the seals. As indicated above, conventional multistage brush seals
exceeding two stages enjoy little, if any, increase in load carrying capability for the third
or more stages.
A further improvement of the multistage seal disclosed may be obtained by predicting or
further testing behavior of the multistage seal and its performance over extended time in
the intended environment. Long term operation of seals is subject to performance
variation due to wear or other factors which affect performance. Evaluation of seal
performance over time may determine changes in engine conditions or blowdown of the
individual stages which may be used for further modifying the seal design for
maintaining its improved performance over extended time of operation.
A particular advantage of the present invention is that the two brush seals 20,22 may
have substantially identical or common designs except for a single design feature thereof
having different configurations for sharing the pressure loading with blowdown, with
preferably equal load sharing. The method illustrated in Figure 3 begins with the
definition of each brush sea! with substantially identical design features and
configurations thereof, including size and dimension and material properties. Each
brush seal includes its pack of bristles mounted between the corresponding forward and
aft plates, with the various geometric dimensions A,B,C and E. And, the two seals are
axially spaced apart by the dimension D.
By modifying the initial design of the brush seals in the sequence of process steps
described above, the seals are reconfigured for sharing the total pressure loading applied
thereacross substantially equally within a suitably small percentage variation, as desired.
And, such load sharing is effected in situ in the intended environment under the effect of
the applied pressure loading which causes corresponding blowdown in each of the seals.
Two design features of the brush seals described above which affect both seal
performance and stability during shaft rubbing are the bristle clearances B1,2 with the
land 12 and the packing density of the bristle packs. Packing density is represented by
the number of bristles per unit length in the circumferential direction around the
perimeter of each brush seal.
The two brush seals may be substantially identical in design and configuration except for
a single design feature thereof in the preferred embodiment which has different
configurations for the different brush seals determined in accordance with the method
disclosed above for preferably equally sharing the pressure loading in the two brush seals
under the effect of blowdown.
In one embodiment of the brush seals illustrated in Figures 1 and 2 produced by the
method illustrated in Figure 3, the seals may be identical in configuration except for the
respective clearances B1,2 between the distal ends of the bristles and the adjacent land
12. In the initial design of the brush seals, the two clearances may be equal, but are
modified in accordance with the method disclosed above for achieving the even load
sharing therebetween under blowdown conditions, and with stability of operation during
rubbing with the shaft 12.
The particular values of the respective clearances will vary from design-to-design based
on the boundary conditions of operation and the basic geometry of the seals and
cooperating land. However, since two-stage conventional brush seals typically share the
overall loading unevenly with more loading being carried by the downstream seal than
the upstream seal, the clearance B2 of the downstream second brush seal 22 illustrated in
Figure 1 is preferably greater than the clearance B1 of the upstream first brush seal 20
for achieving the desired even load sharing under blowdown subject to the very high
pressure loadings intended. Correspondingly, the two brush seal designs may otherwise
be identical, including identical packing densities of the bristles thereof.
In another embodiment represented in Figure 3, the respective packing densities of the
two brush seals may be the single or common design feature which is different in the two
seals for effecting the even load sharing under blowdown, with rotor stability. In this
embodiment, the respective clearances B1,2 of the two brush seals may be equal to each
other, for example zero, for providing an interference or contact fit between the ends of
the bristles and the shaft. Although the bristles contact and therefore rub with the
rotating land 12 during operation, the bristles are still subject to blowdown which
increases the friction forces against the land and affects stability due to friction heating
of the land.
Nevertheless, the method disclosed in Figure 3 may be followed for the different design
features, such as clearance or packing density, to determine the required values thereof
for sharing the pressure loading with blowdown between the two brush seals. Since the
packing density affects leakage of the fluid flow between the bristles, it, like bristle end
clearance, may be tailored or optimized in accordance with the method disclosed above
for adjusting the respective amounts of loads carried by the two brush seals for achieving
the intended even distribution thereof under blowdown.
Another advantage of the method illustrated in Figure 3 is that the multistage seal 10
illustrated in Figure 1 may include two or more brush seals in series, with or without
additional sealing capability such as the labyrinth seal 34 illustrated therein for example.
Labyrinth seals are defined by a series of axially spaced apart annular teeth having
corresponding end clearances with the rotating land 12.
The labyrinth seal 34 illustrated in Figure 1 extends from a common annular flange
integrally formed with the base ends of the first aft plate 28a and the second forward
plate 26b as illustrated. In this way, three stages of seals are provided for collectively
sharing the total differential pressure loading between the axially opposite ends of the
The labyrinth seal 34 itself may be designed and configured in accordance with
conventional practice for sharing some of the total pressure loading, with the remaining
pressure loading being evenly shared between the two brush seals 20,22 configured in
accordance with the method illustrated in Figure 3. A portion of the total pressure
loading may be shared substantially equally between the first and second brush seals
20,22 with their respective loading being different than the pressure loading of the
labyrinth seal in view of the different designs thereof. In view of the enhanced sealing
capability of brush seals, the two brush seals illustrated in Figure 1 will collectively carry
a substantial majority of the total pressure loading across the entire multistage seal
By introducing in the design method illustrated in Figure 3 the affects of blowdown
determined by testing, and the effects of rotor stability, the brush seals are more
accurately designed for use in their intended environment. Accordingly, when the brush
seals are introduced in situ in their intended environment and under the intended pressure
loading thereacross, the load sharing thereof can be substantially equal or even for
maximizing the load carrying capability of each seal and therefore ensuring the
effectiveness and service life of the assembly thereof.
In this way, any conventional brush seal, and in particular brush seals designed for very
high pressure capability, may be modified in accordance with the method disclosed
above for use in series with even load distribution therebetween. The design method
ensures that one brush seal is not overloaded and the other brush seal is not underloaded,
and the collective seal arrangement can therefore carry more total pressure loading than
previously possible. And, more than two brush seals may be designed in accordance
with the method disclosed above for further increasing the total load carrying capability
of the multistage seal assembly for further increasing the total pressure load capability of
the seal, not previously before possible.
While there have been described herein what are considered to be preferred and
exemplary embodiments of the present invention, other modifications of the invention
shall be apparent to those skilled in the art from the teachings herein, and it is, therefore,
desired to be secured in the appended claims all such modifications as fell within the true
spirit and scope of the invention.
Accordingly, what is desired to be secured by Letters Patent of the United States is the
invention as defined and differentiated in the following claims in which we claim:
1. A method of making a multistage seal (10) comprising:
specifying initial first and second brush seals (20,22) having
common designs for collectively sealing a differential pressure
(P1-P2) along a land (12) subject to relative rotation with said
modifying a common design feature of said seals (20,22) to share
loading from said differential pressure without blowdown
modifying said seals (20,22) to ensure rotational stability with
determining pressure blowdown of said seals (20,22) under
pressure, characterized by comprising the step of :
using information obtained from determining pressure blowdown
of said seals (20,22) under pressure for modifying said common
design feature of said seals (20,22) to substantially equally share
said pressure loading under said blowdown.
2. A method as claimed in claim 1 wherein:
said first and second seals (20,22) are initially specified with said common
design having a pack of bristles (24a,b) mounted axially between a
forward plate (26a,b) and an aft plate (28a, b), with distal ends of said
bristles (24a,b) extending in free length therefrom; and
said bristles (24a,b) are modified in free length and stiffness to minimize
heat generation upon rubbing with said land (12) to ensure said rotational
stability with said land (12).
3. A method as claimed in claim 2 wherein:
determining pressure blowdown comprises testing said seals (20,22) to
measure pressures, temperatures, and mass flows of fluid driven
thereacross by said differential pressure (P1 - P2); and
said measured pressures, temperatures, and mass flows are analyzed to
determine said blowdown for each of said seals (20,22).
4. A method as claimed in claim 3, wherein said first and second seals
(20,22) have a common design except for a single design feature
consisting of clearance between said bristle (24a, 24b) ends and said land
(17), and said clearance is different at said first and second seals for
sharing said pressure loading.
5. A method as claimed in claim 3, wherein said first and second seals
(20,22) have a common design except for a single design feature
consisting of packing density of said bristle packs (24a,b), and said
packing density is different for said first and second seals (20,22) for
sharing said pressure loading.
6. A method as claimed in claim 3, wherein said seals (20,22) have a
common design feature differently modifiable for sharing said pressure
loading under said blowdown.
7. A multistage seal produced by carrying-out the method as claimed in
claim 1, wherein said first and second seals (20,22) having substantially
identical designs except for a single design feature having different
configurations in said seals (20,22) for substantially equally sharing said
pressure loading under blowdown in said seals (20,22).
8. A multistage seal as claimed in claim 7, wherein said common design
feature is packing density of said bristle packs, and said packing density is
different for said first and second seals for sharing said pressure.
This invention relates to a method of making a multistage seal (10) comprising:
specifying initial first and second brush seals (20,22) having common designs for
collectively sealing a differential pressure (P1-P2) along a land (12) subject to
relative rotation with said seals (20,22); modifying a common design feature of
said seals (20,22) to share loading from said differential pressure without
blowdown therefrom; modifying said seals (20,22) to ensure rotational stability
with said land; determining pressure blowdown of said seals (20,22) under
pressure. The following step of using information obtained from determining
pressure blowdown of said seals (20,22) under pressure for modifying said
common design feature of said seals (20,22) to substantially equally share said
pressure loading under said blowdown.
|Indian Patent Application Number||356/KOL/2003|
|PG Journal Number||41/2010|
|Date of Filing||26-Jun-2003|
|Name of Patentee||GENERAL ELECTRIC COMPANY|
|Applicant Address||1 RIVER ROAD, SCHENECTADY, NEW YORK|
|PCT International Classification Number||F16J 15/38|
|PCT International Application Number||N/A|
|PCT International Filing date|