CA1229306A - Compressor diaphragm box seal - Google Patents
Compressor diaphragm box sealInfo
- Publication number
- CA1229306A CA1229306A CA000418893A CA418893A CA1229306A CA 1229306 A CA1229306 A CA 1229306A CA 000418893 A CA000418893 A CA 000418893A CA 418893 A CA418893 A CA 418893A CA 1229306 A CA1229306 A CA 1229306A
- Authority
- CA
- Canada
- Prior art keywords
- seal
- shroud
- diaphragm
- compressor
- arcuate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/001—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between stator blade and rotor
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The combustion turbine compressor diaphragm is provided with improved diaphragm box seal. A channel-shaped seal support structure is affixed to the inner surface of the inner shroud. The base of the seal support structure defines a plurality of grooves for receiving seal strips which may be rolled into position and mechan-ically locked, such as by peening. Because the thickness of the seal support base may be increased over that of the inner shroud, the box seal increases the flexibility of seal design. In addition, the box seal improves the structural rigidity of the inner shroud.
The combustion turbine compressor diaphragm is provided with improved diaphragm box seal. A channel-shaped seal support structure is affixed to the inner surface of the inner shroud. The base of the seal support structure defines a plurality of grooves for receiving seal strips which may be rolled into position and mechan-ically locked, such as by peening. Because the thickness of the seal support base may be increased over that of the inner shroud, the box seal increases the flexibility of seal design. In addition, the box seal improves the structural rigidity of the inner shroud.
Description
2~3~6 "
COMPRESSOR DIAPHRAGM BOX SEAL
BACKGROUND OF THE INVENTION
This invention relates generally to compressor diaphragms for combustion turbines and, more particularly, to an improved compressor diaphragm having a more effi-client sealing structure.
In general terms the combustion turbine come poses sQmpreSs~r ses-tlQn, a cQm.hustor sect On, and a turbine section. The compressor section provides a steady ; flow of compressed air to the combustor section, where the compressed air is heated. From the combustor section, the hot pressurized gas is delivered to the turbine section, where gaseous expansion results in rotation of a turbine rotor, which in turn may drive a generator to generate electric power.
Thea compressor section of a combustion turbine typically comprises a plurality of compressor diaphragms arranged alternately between rows of blades affixed to the compressor rotor. Air drawn through the compressor sect lion may typically undergo an increase in pressure to approximately 15 atmospheres. A single compressor die-from may be a disc-shaped structure arranged in two semicircular, or 180, sections. The diaphragm comprises an outer ring, or shroud, and an inner ring, or shroud, with a plurality of airfoil-shaped vanes affixed there-I between. Each compressor diaphragm is assembled around the compressor rotor and between two rows of compressor ~2~3~1~
rotor blades, except at the extreme ends of the compressor rotor.
The inner and outer shrouds typically comprise a metallic plate of approximately .25 inch thickness, rolled to the appropriate diameter. Contoured holes are punched in each shroud at predetermined intervals to receive as inserts extensions from the compressor vanes, which are then welded to each shroud. The thickness of the two shrouds is chosen so as to permit the punching of holes therein, as opposed to machining the holes. In determining the thickness of the plate comprising each shroud, consideration is also given to the life of a punching tool at a given shroud thickness and the increase in structural rigidity, and thereby improved turbine performance, which may be expected from increasing that thickness.
A compressor diaphragm seal is arranged along toe inner circumference of the inner shroud so as to inhibit a leakage flow of compressed air through the annular space between the inner shroud and the turbine rotor. The seal typically comprises a pair of axially spaced angular seal points, having a horizontal arm welded to the inner face of the plate comprising the inner shroud so that a radial warm of each seal point protrudes in warmly, away from the inner shroud to create a small radial gap between itself and a disc seal arm. This arrangement provides a pair of seal points positioned at the opposite axial ends of the inner shroud of each die-from.
A lack of sufficient structural rigidity in the rolled plate comprising the inner shroud results in de election of the inner shroud and a resultant discontinuity at the horizontal joint between the two semicircular structures comprising a single diaphragm. The discontinue-unity at thy horizontal joint causes a flow disturbance which reduces the overall efficiency of the combustion turbine. The use of a rolled plate having a maximum ~L2Z93~?6 thickness of .25 inch to construct the inner shroud con-tributes to the shroud's lack of rigidity. As set forth above, the .25 inch thickness was selected as a balance between fabrication costs and performance efficiency.
A problem which occasionally accompanies turbine compressor operation is the phenomenon of compressor stall. Compressor stall is a condition associated with single compressor stage, which is the combination of a blade row and a vane diaphragm, or a single blade row, or I a single vane diaphragm. A stall condition typically occurs when air flow vectors normally impacting an airfoil surface vary, as a result, for example, of chanting pros-sure and thermal ratios, so as to produce a splitting of the air flow at the leading edge of the airfoil. Stall condition denotes the failure of the blade or vane row to produce its normal increase in pressure. A turbine may have one or more stages or rows operating in the stall condition and yet malnt2in successful operation.
The phenomenon of compressor surge occurs when too many compressor stages or rows are operating in the stall condition. Surge denotes a failure of the entire compressor section ox the turbine and is accompanied by an immediate system shutdown, or turbine trip, and the no-sultan loss of power generation capacity.
A certain amount of flow leakage from the high pressure side of a diaphragm through the diaphragm seal to the low pressure side of the diaphragm seal to the low pressure side of the diaphragm is inherent in typical prior art combustion turbine compressors. The inherence of this leakage arises from the practicality of completely sealing the space between two metallic surfaces, one of which is rotating. Any Leakage through the diaphragm seal results in a distrains of the flow pattern near the inner shroud of the compressor diaphragm. An air flow disturbance may in turn increase the siesta ability of the stage or row to the stall condition and thereby contribute to a compressor surge. The flow disturbance resulting 1~93~
from leakage through a diaphragm seal also contributes to a loss of turbine operating efficiency. Hence, improved efficiency of a diaphragm seal translates into improved turbine operating efficiency and diminished susceptibility to compressor stall and surge.
In summary, typical prior art compressor die-phragms have been structured to operate in a way that limits operating efficiency and to some extent contributes to the possible development of stall and surge conditions during operation. Although these inadequacies do not prevent the combustion turbine from operating satisfactory fly, they do tend to inhibit to some extent the overall operational efficiency of the combustion turbine.
SUMMARY OF THE INVENTION
Accordingly, an improved combustion turbine come presser diaphragm comprises an outer shroud, an inner shroud, a plurality of airfoils supported between the inner and outer shrouds and a boy sell. The compressor diaphragm is preferably structured in two semicircular sections. Affixed to an inner surface of the inner shroud, the box seal provides improved sealing efficiency and increased structural sufficiency for the diaphragm.
The box seal comprises an arcuate seal support base fad-tally spaced from the inner surface of inner shroud and a pair of arcuate legs generally perpendicular to the seal support base and supporting the base in spaced relation-ship from the inner shroud. An inner surface of the seal support base defines a plurality of grooves for receiving a plurality of seal strips.
The box seal arrangement permits the inner shroud to be maintained at a thickness which may be easily punched, while providing a seal support structure of sup fishnet thickness to accommodate grooving and thereby enable attachment of the plurality of seal strips, in contrast to the two seal points available in typical prior art arrangements. The seal strips are mechanically sup-ported in the grooves, rather than welded as in prior ~LZ2~313~6 arrangements. In addition, the mechanically inserted seal strips may be more easily removed and replaced than the welded seal strips of the typical prior art seals. Final-lye the box or channel-shaped structure of the seal sign nificantly increases the structural rigidity of the inner shroud and thereby diminishes the discontinuity typically found at the horizontal joint of the prior art compressor diaphragms. This in turn decreases flow disturbance at the horizontal joint and thereby increases overall operate in efficiency, while diminishing susceptibility of the compressor to stall and surge conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a sectional view of a portion of a compressor section of a combustion turbine;
Figure 2 shows a 180 section of a compressor diaphragm; and Figure 3 shows a sectional view of a compressor diaphragm structured cording to the prinrl~les of. the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 shows a portion of a combustion turbine compressor 10 in cross-section. The compressor lo coy proses a rotor 12, supporting a plurality of rotor blades 14, and an outer compressor casing 16, supporting a plower amity of compressor diaphragms 18. Each diaphragm 18 supports a plurality of compressor vanes 20, only one of which for each diaphragm I may be seen in the sectional view of Figure 1. When operating, the rotor 12 and rotor blades 14 rotate with respect to the compressor casing 16 and the diaphragms 18, drawing air, represented at refer-once character I through the narrowing, annular passage-way 24 to a combustor section (not shown) of the combs-lion turbine. As air is drawn through the compressor section 10, the air pressure gradually increases to apt proximately 15 atmospheres.
Compressed air from the compressor section of the turbine is then heated by a plurality of combustors ~93~;
(not shown) in the combustor section of the turbine. From the combustor section the hot compressed gases are direct-Ed to the turbine section of the combustion turbine, wherein the energy released upon expansion and cooling of the gases is translated into rotation of the combustion turbine rotor. In large combustion turbines used in power generation, the turbine rotor rotation is connected to a generator which thereby generates electric power.
Each compressor diaphragm 18 is constructed in lo two 180, semicircular sections, one of which is depicted in Figure 2. Each compressor diaphragm 18 comprises an outer arcuate shroud 30, an inner arcuate shroud 32, and a plurality of compressor vanes 20. The compressor die-from I shown in Figure 2 with a few vanes 20 for pun-poses of illustration, normally supports a plurality of vanes 20 at regular intervals about the entire annular space between the inner shroud 32 and the outer shroud 30.
To accordance iota the principles of the invention, ye compressor diaphragm 18 is structured with an improved compressor diaphragm box seal 34 for improved structural sufficiency and sealing efficiency. The box seal 34 is shown in greater detail in Figure 3.
Construction of the compressor diaphragm 18 generally progresses as follows. Contoured holes are punched in the outer shroud 30 and in the inner shroud 32, as shown by reference characters 36 and 38, respectively, for receiving extensions of the compressor vane 20. Next, an outer extension 40 of the compressor vane 20 is in-sorted through the hole 36 in the outer shroud and the extension is thereafter welded to the outer shroud as shown at reference characters 42 and 44. This is done for each vane 20 for the diaphragm 18. Next, an inner extent soon of the compressor vane 20 is inserted into the hole 38 and the inner shroud 32 and welded thereto. A semi circular seal support block 35 of channel-shaped cross section is then welded to the inner side of the inner shroud 32. The seal support bloc 35 comprises an arcuate ~ZZS~3~
support base 50 and a pair of arcuate legs 52. After the block welding is completed the seal support block 35 is machined to the final shape shown in Figure 3, including grooves 46 in the inner surface of the support base 50 for receiving seal strips 48, which are preferably formed from sheet metal. The seal strips 48 are thereafter edge-rolled into the grooves 46 and secured by mechanical staking, such as by preening.
The number of seal points 48 included on the support base 50 varies with the position of the diaphragm within the compressor. Generally, the number of seal strips 48 increases with the downstream position of the diaphragm, corresponding to the increasing proximity of blade rows on the compressor rotor and the increased pressures at the downstream end. As can be seen in Figure
COMPRESSOR DIAPHRAGM BOX SEAL
BACKGROUND OF THE INVENTION
This invention relates generally to compressor diaphragms for combustion turbines and, more particularly, to an improved compressor diaphragm having a more effi-client sealing structure.
In general terms the combustion turbine come poses sQmpreSs~r ses-tlQn, a cQm.hustor sect On, and a turbine section. The compressor section provides a steady ; flow of compressed air to the combustor section, where the compressed air is heated. From the combustor section, the hot pressurized gas is delivered to the turbine section, where gaseous expansion results in rotation of a turbine rotor, which in turn may drive a generator to generate electric power.
Thea compressor section of a combustion turbine typically comprises a plurality of compressor diaphragms arranged alternately between rows of blades affixed to the compressor rotor. Air drawn through the compressor sect lion may typically undergo an increase in pressure to approximately 15 atmospheres. A single compressor die-from may be a disc-shaped structure arranged in two semicircular, or 180, sections. The diaphragm comprises an outer ring, or shroud, and an inner ring, or shroud, with a plurality of airfoil-shaped vanes affixed there-I between. Each compressor diaphragm is assembled around the compressor rotor and between two rows of compressor ~2~3~1~
rotor blades, except at the extreme ends of the compressor rotor.
The inner and outer shrouds typically comprise a metallic plate of approximately .25 inch thickness, rolled to the appropriate diameter. Contoured holes are punched in each shroud at predetermined intervals to receive as inserts extensions from the compressor vanes, which are then welded to each shroud. The thickness of the two shrouds is chosen so as to permit the punching of holes therein, as opposed to machining the holes. In determining the thickness of the plate comprising each shroud, consideration is also given to the life of a punching tool at a given shroud thickness and the increase in structural rigidity, and thereby improved turbine performance, which may be expected from increasing that thickness.
A compressor diaphragm seal is arranged along toe inner circumference of the inner shroud so as to inhibit a leakage flow of compressed air through the annular space between the inner shroud and the turbine rotor. The seal typically comprises a pair of axially spaced angular seal points, having a horizontal arm welded to the inner face of the plate comprising the inner shroud so that a radial warm of each seal point protrudes in warmly, away from the inner shroud to create a small radial gap between itself and a disc seal arm. This arrangement provides a pair of seal points positioned at the opposite axial ends of the inner shroud of each die-from.
A lack of sufficient structural rigidity in the rolled plate comprising the inner shroud results in de election of the inner shroud and a resultant discontinuity at the horizontal joint between the two semicircular structures comprising a single diaphragm. The discontinue-unity at thy horizontal joint causes a flow disturbance which reduces the overall efficiency of the combustion turbine. The use of a rolled plate having a maximum ~L2Z93~?6 thickness of .25 inch to construct the inner shroud con-tributes to the shroud's lack of rigidity. As set forth above, the .25 inch thickness was selected as a balance between fabrication costs and performance efficiency.
A problem which occasionally accompanies turbine compressor operation is the phenomenon of compressor stall. Compressor stall is a condition associated with single compressor stage, which is the combination of a blade row and a vane diaphragm, or a single blade row, or I a single vane diaphragm. A stall condition typically occurs when air flow vectors normally impacting an airfoil surface vary, as a result, for example, of chanting pros-sure and thermal ratios, so as to produce a splitting of the air flow at the leading edge of the airfoil. Stall condition denotes the failure of the blade or vane row to produce its normal increase in pressure. A turbine may have one or more stages or rows operating in the stall condition and yet malnt2in successful operation.
The phenomenon of compressor surge occurs when too many compressor stages or rows are operating in the stall condition. Surge denotes a failure of the entire compressor section ox the turbine and is accompanied by an immediate system shutdown, or turbine trip, and the no-sultan loss of power generation capacity.
A certain amount of flow leakage from the high pressure side of a diaphragm through the diaphragm seal to the low pressure side of the diaphragm seal to the low pressure side of the diaphragm is inherent in typical prior art combustion turbine compressors. The inherence of this leakage arises from the practicality of completely sealing the space between two metallic surfaces, one of which is rotating. Any Leakage through the diaphragm seal results in a distrains of the flow pattern near the inner shroud of the compressor diaphragm. An air flow disturbance may in turn increase the siesta ability of the stage or row to the stall condition and thereby contribute to a compressor surge. The flow disturbance resulting 1~93~
from leakage through a diaphragm seal also contributes to a loss of turbine operating efficiency. Hence, improved efficiency of a diaphragm seal translates into improved turbine operating efficiency and diminished susceptibility to compressor stall and surge.
In summary, typical prior art compressor die-phragms have been structured to operate in a way that limits operating efficiency and to some extent contributes to the possible development of stall and surge conditions during operation. Although these inadequacies do not prevent the combustion turbine from operating satisfactory fly, they do tend to inhibit to some extent the overall operational efficiency of the combustion turbine.
SUMMARY OF THE INVENTION
Accordingly, an improved combustion turbine come presser diaphragm comprises an outer shroud, an inner shroud, a plurality of airfoils supported between the inner and outer shrouds and a boy sell. The compressor diaphragm is preferably structured in two semicircular sections. Affixed to an inner surface of the inner shroud, the box seal provides improved sealing efficiency and increased structural sufficiency for the diaphragm.
The box seal comprises an arcuate seal support base fad-tally spaced from the inner surface of inner shroud and a pair of arcuate legs generally perpendicular to the seal support base and supporting the base in spaced relation-ship from the inner shroud. An inner surface of the seal support base defines a plurality of grooves for receiving a plurality of seal strips.
The box seal arrangement permits the inner shroud to be maintained at a thickness which may be easily punched, while providing a seal support structure of sup fishnet thickness to accommodate grooving and thereby enable attachment of the plurality of seal strips, in contrast to the two seal points available in typical prior art arrangements. The seal strips are mechanically sup-ported in the grooves, rather than welded as in prior ~LZ2~313~6 arrangements. In addition, the mechanically inserted seal strips may be more easily removed and replaced than the welded seal strips of the typical prior art seals. Final-lye the box or channel-shaped structure of the seal sign nificantly increases the structural rigidity of the inner shroud and thereby diminishes the discontinuity typically found at the horizontal joint of the prior art compressor diaphragms. This in turn decreases flow disturbance at the horizontal joint and thereby increases overall operate in efficiency, while diminishing susceptibility of the compressor to stall and surge conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a sectional view of a portion of a compressor section of a combustion turbine;
Figure 2 shows a 180 section of a compressor diaphragm; and Figure 3 shows a sectional view of a compressor diaphragm structured cording to the prinrl~les of. the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 shows a portion of a combustion turbine compressor 10 in cross-section. The compressor lo coy proses a rotor 12, supporting a plurality of rotor blades 14, and an outer compressor casing 16, supporting a plower amity of compressor diaphragms 18. Each diaphragm 18 supports a plurality of compressor vanes 20, only one of which for each diaphragm I may be seen in the sectional view of Figure 1. When operating, the rotor 12 and rotor blades 14 rotate with respect to the compressor casing 16 and the diaphragms 18, drawing air, represented at refer-once character I through the narrowing, annular passage-way 24 to a combustor section (not shown) of the combs-lion turbine. As air is drawn through the compressor section 10, the air pressure gradually increases to apt proximately 15 atmospheres.
Compressed air from the compressor section of the turbine is then heated by a plurality of combustors ~93~;
(not shown) in the combustor section of the turbine. From the combustor section the hot compressed gases are direct-Ed to the turbine section of the combustion turbine, wherein the energy released upon expansion and cooling of the gases is translated into rotation of the combustion turbine rotor. In large combustion turbines used in power generation, the turbine rotor rotation is connected to a generator which thereby generates electric power.
Each compressor diaphragm 18 is constructed in lo two 180, semicircular sections, one of which is depicted in Figure 2. Each compressor diaphragm 18 comprises an outer arcuate shroud 30, an inner arcuate shroud 32, and a plurality of compressor vanes 20. The compressor die-from I shown in Figure 2 with a few vanes 20 for pun-poses of illustration, normally supports a plurality of vanes 20 at regular intervals about the entire annular space between the inner shroud 32 and the outer shroud 30.
To accordance iota the principles of the invention, ye compressor diaphragm 18 is structured with an improved compressor diaphragm box seal 34 for improved structural sufficiency and sealing efficiency. The box seal 34 is shown in greater detail in Figure 3.
Construction of the compressor diaphragm 18 generally progresses as follows. Contoured holes are punched in the outer shroud 30 and in the inner shroud 32, as shown by reference characters 36 and 38, respectively, for receiving extensions of the compressor vane 20. Next, an outer extension 40 of the compressor vane 20 is in-sorted through the hole 36 in the outer shroud and the extension is thereafter welded to the outer shroud as shown at reference characters 42 and 44. This is done for each vane 20 for the diaphragm 18. Next, an inner extent soon of the compressor vane 20 is inserted into the hole 38 and the inner shroud 32 and welded thereto. A semi circular seal support block 35 of channel-shaped cross section is then welded to the inner side of the inner shroud 32. The seal support bloc 35 comprises an arcuate ~ZZS~3~
support base 50 and a pair of arcuate legs 52. After the block welding is completed the seal support block 35 is machined to the final shape shown in Figure 3, including grooves 46 in the inner surface of the support base 50 for receiving seal strips 48, which are preferably formed from sheet metal. The seal strips 48 are thereafter edge-rolled into the grooves 46 and secured by mechanical staking, such as by preening.
The number of seal points 48 included on the support base 50 varies with the position of the diaphragm within the compressor. Generally, the number of seal strips 48 increases with the downstream position of the diaphragm, corresponding to the increasing proximity of blade rows on the compressor rotor and the increased pressures at the downstream end. As can be seen in Figure
3, the support base 50 ma be arranged to support more or fewer seal strips 48, depending upon the physical require-m~n'CS _ The compressor diaphragm box seal 34 provides a 0 number of advantages over prior art seals described in toes Background Of The Invention. The I base 50 of the seal support block 35 is thick enough to support machining of a plurality of grooves 46; whereas, thy inner shroud 32 which was maintained to a maximum thickness of approx-irately .25 inch, was not thick enough to support machine in of the grooves therein. As a result, tune seal support block 35 can support a plurality of seal points 48 while the inner shroud 32 was capable of supporting only a pair of seal points which had to be welded thereto. The come presser diaphragm box seal I provides for improved effi-Chinese over the two-point inner shroud seal by increasing the number of seal strips used. In addition, the mechanic gaily staked seal strips 48 of the box seal 34 are more readily removed and replaced than the two seal points of the prior art which were rigidly welded to the inner shroud 32.
~L2Z~3~
A further advantage of the box seal 34 is the increased structural rigidity provided to the sheet metal seal strips 48. In prior art designs, the seal strips were required to extend radially from the inner surface of the inner shroud 32 to the compressor disc seal arms.
Flow-induced excitation caused the seal strips to vibrate, resulting in reduced fatigue life of the long seal strips.
In addition to offering a more rigid point of attachment for the seals, the box seal 34 permits use of seal strips which are shorter in radial length and, hence, more nests-lent to fatigue than prior art seal strips.
Still another advantage of the box seal 34 is the increased structural rigidity which it provides to the inner shroud 32. Maintaining the inner shroud I to a thickness which can be mechanically punched results in a structure subject to deflection, producing discontinuities at the horizontal joints of the compressor diaphragms.
The box seal 34 effectively increases the thickness of the inner shroud and correspondingly increases the structural rigidity of the inner shroud, significantly improving the continuity at the horizontal joint. This reduces or elm-inmates flow disturbances which occurred at the horizontal joint in prior art compressors and thereby increases the overall efficiency of the combustion turbine.
A final advantage of the box seal 34 is the increased torsional rigidity provided to the inner shroud 32. In prior art designs, variations in the axial deflect lion of individual vanes 20 caused a war page or twist in the inner shroud 32. The resultant distortions in the exposed surface of the inner shroud 32 caused flow disturb banes and a decrease in operating efficiency. By erect-in a "torque box," the box seal 34 and inner shroud 32 combination greatly reduces susceptibility of the inner shroud 32 to war page and thereby promotes operating effi-Chinese.
~L2Z~3~
A further advantage of the box seal 34 is the increased structural rigidity provided to the sheet metal seal strips 48. In prior art designs, the seal strips were required to extend radially from the inner surface of the inner shroud 32 to the compressor disc seal arms.
Flow-induced excitation caused the seal strips to vibrate, resulting in reduced fatigue life of the long seal strips.
In addition to offering a more rigid point of attachment for the seals, the box seal 34 permits use of seal strips which are shorter in radial length and, hence, more nests-lent to fatigue than prior art seal strips.
Still another advantage of the box seal 34 is the increased structural rigidity which it provides to the inner shroud 32. Maintaining the inner shroud I to a thickness which can be mechanically punched results in a structure subject to deflection, producing discontinuities at the horizontal joints of the compressor diaphragms.
The box seal 34 effectively increases the thickness of the inner shroud and correspondingly increases the structural rigidity of the inner shroud, significantly improving the continuity at the horizontal joint. This reduces or elm-inmates flow disturbances which occurred at the horizontal joint in prior art compressors and thereby increases the overall efficiency of the combustion turbine.
A final advantage of the box seal 34 is the increased torsional rigidity provided to the inner shroud 32. In prior art designs, variations in the axial deflect lion of individual vanes 20 caused a war page or twist in the inner shroud 32. The resultant distortions in the exposed surface of the inner shroud 32 caused flow disturb banes and a decrease in operating efficiency. By erect-in a "torque box," the box seal 34 and inner shroud 32 combination greatly reduces susceptibility of the inner shroud 32 to war page and thereby promotes operating effi-Chinese.
Claims (5)
1. A combustion turbine compressor diaphragm having an upstream side and a downstream side, said diaphragm arranged in two opposing sections, the assembled combination of which circumscribes a compressor rotor, each said section comprising:
an outer arcuate shroud;
an inner arcuate shroud of lesser radius than and arranged concentric with said outer shroud, said inner shroud having an inner surface spaced from and facing the compressor rotor when assembled;
a plurality of airfoils fixedly supported by and between said inner and outer shrouds, said plurality of air-foils arranged to direct fluid flowing generally perpendicular to the plane of said inner and said outer shrouds;
said inner shroud being formed from a ring-like arcuate section of plate thin enough to permit machine punching of holes in the inner shroud plate for receiving inner ends of said airfoils; and means for sealing said diaphragm relative to the compressor rotor, said sealing means comprising an arcuate base having a predetermined number of radially inwardly facing arcuate grooves for sealing strips and having sufficient thickness to support machining of said grooves, and wall means extending radially outwardly for securance to said ring-like inner shroud plate to stiffen said diaphragm against warping.
an outer arcuate shroud;
an inner arcuate shroud of lesser radius than and arranged concentric with said outer shroud, said inner shroud having an inner surface spaced from and facing the compressor rotor when assembled;
a plurality of airfoils fixedly supported by and between said inner and outer shrouds, said plurality of air-foils arranged to direct fluid flowing generally perpendicular to the plane of said inner and said outer shrouds;
said inner shroud being formed from a ring-like arcuate section of plate thin enough to permit machine punching of holes in the inner shroud plate for receiving inner ends of said airfoils; and means for sealing said diaphragm relative to the compressor rotor, said sealing means comprising an arcuate base having a predetermined number of radially inwardly facing arcuate grooves for sealing strips and having sufficient thickness to support machining of said grooves, and wall means extending radially outwardly for securance to said ring-like inner shroud plate to stiffen said diaphragm against warping.
2. A diaphragm according to claim 1 wherein said sealing means comprises:
an arcuate seal support base having an inner surface facing the compressor rotor, said base being radially spaced from and generally concentric with the inner surface of said inner shroud, the inner surface of said base defining a plur-ality of grooves;
a pair of arcuate legs generally perpendicular to and continuous with said seal support base, said pair of legs being rigidly affixed to the inner surface of said inner shroud;
and a plurality of arcuate seal strips for insertion in at least two of the grooves in the inner surface of said base.
an arcuate seal support base having an inner surface facing the compressor rotor, said base being radially spaced from and generally concentric with the inner surface of said inner shroud, the inner surface of said base defining a plur-ality of grooves;
a pair of arcuate legs generally perpendicular to and continuous with said seal support base, said pair of legs being rigidly affixed to the inner surface of said inner shroud;
and a plurality of arcuate seal strips for insertion in at least two of the grooves in the inner surface of said base.
3. A diaphragm according to claim 2 wherein at least one of said plurality of seal strips are mechanically locked into the grooves by peening.
4. A diaphragm according to claim 2 wherein said base and said pair of legs are machined as one piece from a single stock.
5. A diaphragm according to claim 2 wherein said pair of legs are rigidly affixed to said base by welding.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US34103782A | 1982-01-20 | 1982-01-20 | |
| US341,037 | 1982-01-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1229306A true CA1229306A (en) | 1987-11-17 |
Family
ID=23336004
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000418893A Expired CA1229306A (en) | 1982-01-20 | 1983-01-05 | Compressor diaphragm box seal |
Country Status (9)
| Country | Link |
|---|---|
| JP (2) | JPS58124025A (en) |
| AR (1) | AR229634A1 (en) |
| BE (1) | BE895651A (en) |
| BR (1) | BR8300073A (en) |
| CA (1) | CA1229306A (en) |
| GB (1) | GB2113772B (en) |
| IT (1) | IT1173652B (en) |
| MX (1) | MX154757A (en) |
| SE (1) | SE455219B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3631271B2 (en) * | 1993-11-19 | 2005-03-23 | ユナイテッド テクノロジーズ コーポレイション | Inner shroud integrated stator vane structure |
| US5584654A (en) * | 1995-12-22 | 1996-12-17 | General Electric Company | Gas turbine engine fan stator |
| JP5091615B2 (en) | 2007-10-15 | 2012-12-05 | 三菱重工業株式会社 | Stator blade ring segment assembly method, stator blade ring segment, connecting member, welding method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5268613A (en) * | 1975-12-04 | 1977-06-07 | Agency Of Ind Science & Technol | Cooling device for inner diameterside sealing material of nozzle-wing in turbo-fan engine |
-
1983
- 1983-01-03 SE SE8300022A patent/SE455219B/en not_active IP Right Cessation
- 1983-01-05 CA CA000418893A patent/CA1229306A/en not_active Expired
- 1983-01-10 BR BR8300073A patent/BR8300073A/en unknown
- 1983-01-12 MX MX195892A patent/MX154757A/en unknown
- 1983-01-12 IT IT19068/83A patent/IT1173652B/en active
- 1983-01-14 GB GB08300980A patent/GB2113772B/en not_active Expired
- 1983-01-19 BE BE0/209932A patent/BE895651A/en not_active IP Right Cessation
- 1983-01-20 AR AR291904A patent/AR229634A1/en active
- 1983-01-20 JP JP58006753A patent/JPS58124025A/en active Pending
-
1986
- 1986-12-02 JP JP1986185117U patent/JPH0128245Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2113772A (en) | 1983-08-10 |
| IT1173652B (en) | 1987-06-24 |
| MX154757A (en) | 1987-12-09 |
| SE8300022L (en) | 1983-07-21 |
| SE8300022D0 (en) | 1983-01-03 |
| AR229634A1 (en) | 1983-09-30 |
| GB2113772B (en) | 1985-10-09 |
| SE455219B (en) | 1988-06-27 |
| BE895651A (en) | 1983-07-19 |
| JPH0128245Y2 (en) | 1989-08-29 |
| BR8300073A (en) | 1983-09-20 |
| JPS62101042U (en) | 1987-06-27 |
| JPS58124025A (en) | 1983-07-23 |
| GB8300980D0 (en) | 1983-02-16 |
| IT8319068A0 (en) | 1983-01-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |