CA1130545A - Apparatus for remotely repairing tubes in a steam generator - Google Patents
Apparatus for remotely repairing tubes in a steam generatorInfo
- Publication number
- CA1130545A CA1130545A CA338,846A CA338846A CA1130545A CA 1130545 A CA1130545 A CA 1130545A CA 338846 A CA338846 A CA 338846A CA 1130545 A CA1130545 A CA 1130545A
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- Canada
- Prior art keywords
- boom
- column
- platform
- tubesheet
- disposed
- Prior art date
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Abstract
47,746 IMPROVED APPARATUS FOR REMOTELY REPAIRING
TUBES IN A STEAM GENERATOR
ABSTRACT OF THE DISCLOSURE
Apparatus that may be assembled inside the head of a steam generator and can perform various repair and inspec-tion operations on the steam generator's tubes and tube-sheet. Selective engagement of an included tool holder and associated tools with the tube and tubesheet is provided by a gear train which has a portion which houses a tool drive motor. The drive motor provides power to a tool holder-mounted tool chuck for driving the various tools insertable therein.
TUBES IN A STEAM GENERATOR
ABSTRACT OF THE DISCLOSURE
Apparatus that may be assembled inside the head of a steam generator and can perform various repair and inspec-tion operations on the steam generator's tubes and tube-sheet. Selective engagement of an included tool holder and associated tools with the tube and tubesheet is provided by a gear train which has a portion which houses a tool drive motor. The drive motor provides power to a tool holder-mounted tool chuck for driving the various tools insertable therein.
Description
Thl~ ln~ention relates to nuclear dteam generators and more particularly to apparatu~ for remotely repalrlng : ~ the tubPs and tubesheet in a nuclear ~team generator.
Rad1oacti~e contaminantq in the primary fluld o~ a pres~urized water nuclear reactor sy~tem sometlme~ depo~it . on the tubes and in the channel head oi the nuclear ~team generator causlng repalr perso~nel who work within the : 20 channel head to be subjected to signi~icant radioacti~lty.
It i~ de~iral~le ~o provide an appara*u~ which c~n e~Pect--~ lvely inspect and repalr tubes and the a~soclated tube~heet .
within the steam generator from a remote location so a~ to reduce the e~posure o~ work personnel to the radiation present withln the channel head.
o~ the Prior Art:
United States Patant 4,205~940 is~ued June 3 1980 to L. R. Goli~k et al ,@~.
~ 3~ S~5 47,746 and assigned to the assignee of the present application shows an apparatus similar to the present inYention~ Such apparatus~ however9 utilized hydraulic positioning means for moving the apparatus' plat~orm portion relative to the base along a direct$on known as the 2 axis. While the ; a~orementioned apparatus admirably per~ormed the required repair work withln the char~el head~ its ~ydraulic positio-ning mechanism lacked the extreme precision and stability which was sometimes necessary ~or certain specific tool operations. Due to inherent characteristics of two-way hydraulic cylinders9 the prior art's posit~oning mechanism was ~ound to be somewhat slow ln one o~ the two directions of travel.
An apparatus for remotely repairing a tubesheet and tubes associated therewith ~n a channel head o~ a steam generator when made ln accordance with this lnvention com-prises a colllmn rotatably disposed in the head generally perpendlcular to the tubesheet with one end o~ the colu~n terminating a predeter~ined distance from the ~ubesheet, a boom pivotally mounted adjacent the terminal end of the column, a device ~or rotating the column and boom therewith, a locking device for securing the column and boom ln any rotated position, a device for pi~oting the boom between `
positions generally parallel to the tubesheet and generally aligned with a manway disposed in the steam generatorls head, a carriage disposed to translate along the boom, a mechanism for moving the carriage along the boom and locking it at any position thereon. me carriage constitutes a bass disposed generally parallel to the tubesheet when the boom's longitudinal axis is generally parall~l to the tubesheet, a . ~ 47,7L16 ~' ; platform disposed generally parallel to the base, a posi-tioning motor and associated gear train for moving the platform relative to the base, a mechanism ~or maintaining a . parallel relation between the platform and base during `~ relative movement therebetween, a tool holder cantilevered over and supported by the platform, a tool chuck associated : with the plat~orm ~or grasping tools inserted therein, and a drive motor which is movable with the plat~orm and provides `. power for driving the tool-grasping chuc~ which is disposed 10 on the distal end of the cantilevered tool holder. The tool drive motor is housed within a gear of the positioning gear train.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and advantages of the present inven- ~:
tion will be more fully understood ~rom the ~ollowing de-tailed description o~ the pre~erred embodiment, taken in connection with the accompanying drawings, in which~
i Figure 1 is a partial sectional view of a steam generator head with an apparatus made in accordance with the present invention disposed therein ~or remotely repairing the tubes and tubesheets;
Figure 2 is a partial sectional view of a tool holding carriage utiii~ed in the present invention;
Figure 3 is a partial sectional view taken along the lines indicated in Figure 2;
Figure 4 is a partial sectional plan view o~ the carriage shown in Figure 2; and Figure 5 is a plan view o~ a tool holder included in the carriage.
3~ 5~
47,746 ; DESCRIPTION OF THE PREFERRED EMBODI~EWT
Re~erring now to the drawlngs in detail, Figure 1 illustrates a portion o~ channel head 10 included in a steam generator 12 ~rhich also has a tubesheet 14 with a plurallty o~ holes 16 formed therein. Tubes 18 are disposed ln holes 16 ~d extend upwardly in operational position ~rom tube-sheet 14. The channel head 10 ha~ a generally hemispherical wall 20 and is divided into an inlet portion and outlet portion (only one o~ which is shown in the drawings) by a dividing plate 22. Each portion has a ma~way 24 dlsposed in the wall 20~ but it is to be understood that the pre~ent inYention can be utilized with equal ~acility in a channel head 10 whose inlet and outlet portions are accessible ~ -through a single manway 24.
An apparatus ~or remo-tely repalring and inspeoting : ;
-the tubes 18 and tubesheet 14 is generally indicated at 26 disposed in one portion of the channel head 10 and comprises ~:
; : a vertically oriented column 28 which is plvotally connected - -to the wall 20 o~ the channel head 10 and extends generally upwardly therefrom, me column 28 is generally pe~pendicu~
lar to the tub~sheet 14 and is disposed adJacent t~e divid-ing plate 22. A spherical bear~ng 30 is disposed at the :
~oot o~ colunGI 28 in a bearing hous~ng 32 which ls ~astened `~
to the wall 20 by welding or other me~ns and ~orms a first ~;
support means ~or the column 28. A second support means 34 is fastened to the dividing plate 22 by ~eldlng or other 3~S~ 47,7~6 means and is disposed intermediate the ends of column28. The second support means 34 includes an anti-friction apparatus such as ball or roller bearings (not shown) which are disposed about and permit rotation of column 28 therein.
Split collar 36 is included in the second support means 34 and has a gap 38 which may be closed by hydraulic cyl~nder 40 to lock the column 28 in any selected rotated position.
As shown in Figure 1, the second support 34 has X
and Y ad~ustments in a plane generally parallel to the tubesheet ~or insuring proper column alignment perpendicular to tubesheet 14. Movement in the X direction is afforded by dovetail 42 and adJusting screw 4LI. A set screw 46 locks the dovetail 42 in position when the column 28 is plumb in one direction. The other degree of movement, ~, is provided by ~ackscrews and clevis mounted bolts 48 or other appro- ;~
priate means such as shims. The terminal or upper end of .
column 28 terminates a predetermined distance from the tubesheet 14 so as to avoid rotating interference therewith.
A boom 50 is pivotally connected to the terminal .
20 end of column 28 by a suitable mounting bracket 52. The pivotal connection is such that the boom 50 rotates with column 28 and can pivot from a position generally parallel to the tubesheet 14 to a position generally aligned with -~
manway 24. A pair of telescoping hydraulic cylinders 54 :
(only one shown) are pivotally connected to the lower end of column 28 by a suitable bracket 56 and to the distal end of boom 50 by connection bracket 58 to provide means for pivot-ing the boom 50 from the position generally parallel to tubesheet 14 to the position generally aligned with the manway 24.
~:~3~5~5 47,7ll6 A hollow shaft DC motor 60 is disposed about column 28 and is connected thereto. Motor 60 has a rnotor base 62 with ad~ustable feet 64 which engage the dividing plate 22 to provide means for rotating the column 28 and the boom 50 therewith. Disposed w:ithin the motor 60 are means ~or indicating the angular position of the hollow shaft.
The motor 60 iS reversible to provide rotatlon of column 28 and boom 50 in either direction.
The boom 50 comprises a pair of generally parallel lO rails or channels 66 with guideways 68 disposed on the top - ~;
and bottom portion of each channel 66. The guideways 68 extend longitudinally along the boom 50 and are parallel to each other. A carriage 70 is slidably disposed on the guideways 68 and has a pair of bearings 72 which slidably engage each of the guideways 68 so as to cause the carriage ;
70 to move rectilinearly and parallel to the longitudinal axis of the boom ~0.
The carriage 70, as best shown in Figures 2 and 3, comprises a base 74 and a platform 76 which are disposed ~; `
20 generally parallel to each other and to the tubesheet 14 when the longitudinal axis of the boom 50 is parallel there-to. The base 74 is connected to bearings 72 while the platform 76 is disposed above and parallel to base 74. An ~ ~-air motor 78 or other drive means, is connected to plat~orm 76.
Means for moving platform 76 with respect to base 74 comprises a reversible electric motor 80 or other posi-tioning means for driving a gear train 82. Platform 76 is moved relative to base 74 along a Z axis through gear train 30 82 which comprises two mateable bevel gears 84 and 86, two ` ~3~S~5 47,746 mateable spur gears 88 and 90, worm gear 92, worm wheel .:
94, and threaded sleeve or hollow lead screw 96. ~ear train 82 is best illustrated in Figure 4 which is a partial sectional plan view of the carriage 70 of Figure 2. Worm wheel 94 is driven by worm gear 92 which mates with gear teeth formed on worm wheel 94 ' s exterior. The lnner peri-phery of worm wheel ~4 is machined to mate with lead screw 96 and convert rotary motion imparted to worm wheel. 94 into `
vertical translational movement of lead screw 96. Selective rotation of reversible electric motor 80 provldes a raising and lowering of lead screw 96 and connected platrorm 76. ~
Air motor 78 is supported in lead screw 96 so as to move ~ :
with platform 76 in its upward and downward motions. -~
Means ~or maintaining a parallel relation between base 74 and platform 76 preferably comprises four round bars 98 which are affixed ad~acent the four corners of platform 76 and eight ball bushings 100 disposed in base 74 for slidably receiving bars 98. ~
A cantilevered tool holder 102 is fastened to ; ~.:
20 platform 76 and coupled to air drive motor 78. The canti~
levered tool holder 102, better illustrated in Figure 5, has ~
a tool receptacle or chuck 104 on the distal end thereof for ;~ `
grasping tool 105 and a train of gears or other drive means 106 connecting the drive motor 78 to the tool chuck 104 providing power to drive a tool 105. ;
Ball screw 108, drive motor 110, and ball nut 112 are cooperatively associated with boom 50 and carriage 70 to .
provide means for moving the carriage 70 rectllinearly along ..
the boom 50 and for holding the carriage 70 at any position along the boom 50. The ball screw 108 extends the length of . 1.3~ 1S
47,746 boom 50 and is disposed generally parallel to the longitudinal axis thereof. The ball nut 112 is aff'ixed to the carriage 70 and engages the threads of ball screw 108.
Position indicating means 114 is provided to display the position of carriage 70 along boom 50. A pair (only one ls shown) of hydraulic cylinders 116 which can be extended to contact wall 20 of the head 10 to steady boom 50 when the tool 105 is performing an operation on the tubes 18 or tubesheet 14.
The cantilevered tool holder 102, as best shown in Figure 4, has arcuate plates 118 equally spaced on opposlte sides of the axis of the drive motor 78. Lugs 120 clamp the ~.arcuate plates 118 and tool holder 102 to the platform 76.
Dowels and dowel holes (not shown) are provided in the arcuate plates 118 and in the platform 76 to permit align-ment of the cantilevered tool holder 102 wi.th the axis of boom 50 as shown in Figure 1, rotated 180, or rotated to form an acute angle with respect to the axis of boom 50, as :
shown in phantom in Figure 4. The varying positions of tool .~ .
holder 102 column 28 cooperate to provide access to all the tubes in any selected portion of the tubesheet 14 and estab- -lish accurate positioning of the tool holder 102 to allow remotely controlled repeated operation on any tube 18 in that portion of the tubesheet 14. ; ~A C-shaped stiffening bracket 122 is ~astened to :
the column 28 and spans the motor 60 in order to reduce de-flection o.~ column 28 and minimi~e the forces on the motor 60's bearings.
The apparatus hereinbefore described may be easily and quickly installed in the head 10 of a steam generator 12 -8~
~ 3~ 5~ 47,746 and, with an assortment of tools 105, can perform various operations on all of the tubes 18 in a selected portion of the tubesheet 14 being limited only by dividing plate 22.
The apparatus so structured is rugged and reliable to permit operation within the close tolerances necessary to retube a steam generator utilizing remote controls. To operate re-motely, the angular position of the boom 50 in column 28 must be repeatable. Accurate angular positioning of column 28 and boom 50 and lndications thereof are provided by motor 60 with positional locking of the interconnected column 2 and boom 50 being provided by split collar 36 locking column 28 in the desired angular position.
The carriage 70 is positioned by rotating the ball screw 108 with motor 110 which has a brake disposed therein to lock ball screw 108 in any desired position. Ball screw nut 112 rides on the threads of screw 108 and has a plural-ity of balls which engage the threads thereof. This co-operating combination of screw and nut minimizes backlash allowing precise positioning of the carriage 70 and is not sub~ect to backdriving by the carriage. Thus, when motor llO's brake ls engaged, carriage 70 remains fixed in any desired position.
The hydraulic cylinders 54 which raise boom 50 ~ ~;
from a position aligned with manway 24 to a position where -boom 50 is generally parallel to the tubesheet 14 preferably acts against a stop in the latter position to increase the rigidity of the entire apparatus 26.
It will no~ be apparent that an improved remotely operable repair apparatus has been provided in which a highly compact tool positioning mechanism is utilized to _g_ :
, ~:
- ~13(~5~S ll7, 7ll6 mechanically engage selected tools 105 with tubesheet 14 and tubes 18. The mechanical positioning mechanism's construction results in a structure whose control is precise and whose size permits Or easy entry to the head's interior through the manway 24.
-10- ~`
, . . . ,, , . . .. ~ , .. ,, . ~ . . - . . ...
Rad1oacti~e contaminantq in the primary fluld o~ a pres~urized water nuclear reactor sy~tem sometlme~ depo~it . on the tubes and in the channel head oi the nuclear ~team generator causlng repalr perso~nel who work within the : 20 channel head to be subjected to signi~icant radioacti~lty.
It i~ de~iral~le ~o provide an appara*u~ which c~n e~Pect--~ lvely inspect and repalr tubes and the a~soclated tube~heet .
within the steam generator from a remote location so a~ to reduce the e~posure o~ work personnel to the radiation present withln the channel head.
o~ the Prior Art:
United States Patant 4,205~940 is~ued June 3 1980 to L. R. Goli~k et al ,@~.
~ 3~ S~5 47,746 and assigned to the assignee of the present application shows an apparatus similar to the present inYention~ Such apparatus~ however9 utilized hydraulic positioning means for moving the apparatus' plat~orm portion relative to the base along a direct$on known as the 2 axis. While the ; a~orementioned apparatus admirably per~ormed the required repair work withln the char~el head~ its ~ydraulic positio-ning mechanism lacked the extreme precision and stability which was sometimes necessary ~or certain specific tool operations. Due to inherent characteristics of two-way hydraulic cylinders9 the prior art's posit~oning mechanism was ~ound to be somewhat slow ln one o~ the two directions of travel.
An apparatus for remotely repairing a tubesheet and tubes associated therewith ~n a channel head o~ a steam generator when made ln accordance with this lnvention com-prises a colllmn rotatably disposed in the head generally perpendlcular to the tubesheet with one end o~ the colu~n terminating a predeter~ined distance from the ~ubesheet, a boom pivotally mounted adjacent the terminal end of the column, a device ~or rotating the column and boom therewith, a locking device for securing the column and boom ln any rotated position, a device for pi~oting the boom between `
positions generally parallel to the tubesheet and generally aligned with a manway disposed in the steam generatorls head, a carriage disposed to translate along the boom, a mechanism for moving the carriage along the boom and locking it at any position thereon. me carriage constitutes a bass disposed generally parallel to the tubesheet when the boom's longitudinal axis is generally parall~l to the tubesheet, a . ~ 47,7L16 ~' ; platform disposed generally parallel to the base, a posi-tioning motor and associated gear train for moving the platform relative to the base, a mechanism ~or maintaining a . parallel relation between the platform and base during `~ relative movement therebetween, a tool holder cantilevered over and supported by the platform, a tool chuck associated : with the plat~orm ~or grasping tools inserted therein, and a drive motor which is movable with the plat~orm and provides `. power for driving the tool-grasping chuc~ which is disposed 10 on the distal end of the cantilevered tool holder. The tool drive motor is housed within a gear of the positioning gear train.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and advantages of the present inven- ~:
tion will be more fully understood ~rom the ~ollowing de-tailed description o~ the pre~erred embodiment, taken in connection with the accompanying drawings, in which~
i Figure 1 is a partial sectional view of a steam generator head with an apparatus made in accordance with the present invention disposed therein ~or remotely repairing the tubes and tubesheets;
Figure 2 is a partial sectional view of a tool holding carriage utiii~ed in the present invention;
Figure 3 is a partial sectional view taken along the lines indicated in Figure 2;
Figure 4 is a partial sectional plan view o~ the carriage shown in Figure 2; and Figure 5 is a plan view o~ a tool holder included in the carriage.
3~ 5~
47,746 ; DESCRIPTION OF THE PREFERRED EMBODI~EWT
Re~erring now to the drawlngs in detail, Figure 1 illustrates a portion o~ channel head 10 included in a steam generator 12 ~rhich also has a tubesheet 14 with a plurallty o~ holes 16 formed therein. Tubes 18 are disposed ln holes 16 ~d extend upwardly in operational position ~rom tube-sheet 14. The channel head 10 ha~ a generally hemispherical wall 20 and is divided into an inlet portion and outlet portion (only one o~ which is shown in the drawings) by a dividing plate 22. Each portion has a ma~way 24 dlsposed in the wall 20~ but it is to be understood that the pre~ent inYention can be utilized with equal ~acility in a channel head 10 whose inlet and outlet portions are accessible ~ -through a single manway 24.
An apparatus ~or remo-tely repalring and inspeoting : ;
-the tubes 18 and tubesheet 14 is generally indicated at 26 disposed in one portion of the channel head 10 and comprises ~:
; : a vertically oriented column 28 which is plvotally connected - -to the wall 20 o~ the channel head 10 and extends generally upwardly therefrom, me column 28 is generally pe~pendicu~
lar to the tub~sheet 14 and is disposed adJacent t~e divid-ing plate 22. A spherical bear~ng 30 is disposed at the :
~oot o~ colunGI 28 in a bearing hous~ng 32 which ls ~astened `~
to the wall 20 by welding or other me~ns and ~orms a first ~;
support means ~or the column 28. A second support means 34 is fastened to the dividing plate 22 by ~eldlng or other 3~S~ 47,7~6 means and is disposed intermediate the ends of column28. The second support means 34 includes an anti-friction apparatus such as ball or roller bearings (not shown) which are disposed about and permit rotation of column 28 therein.
Split collar 36 is included in the second support means 34 and has a gap 38 which may be closed by hydraulic cyl~nder 40 to lock the column 28 in any selected rotated position.
As shown in Figure 1, the second support 34 has X
and Y ad~ustments in a plane generally parallel to the tubesheet ~or insuring proper column alignment perpendicular to tubesheet 14. Movement in the X direction is afforded by dovetail 42 and adJusting screw 4LI. A set screw 46 locks the dovetail 42 in position when the column 28 is plumb in one direction. The other degree of movement, ~, is provided by ~ackscrews and clevis mounted bolts 48 or other appro- ;~
priate means such as shims. The terminal or upper end of .
column 28 terminates a predetermined distance from the tubesheet 14 so as to avoid rotating interference therewith.
A boom 50 is pivotally connected to the terminal .
20 end of column 28 by a suitable mounting bracket 52. The pivotal connection is such that the boom 50 rotates with column 28 and can pivot from a position generally parallel to the tubesheet 14 to a position generally aligned with -~
manway 24. A pair of telescoping hydraulic cylinders 54 :
(only one shown) are pivotally connected to the lower end of column 28 by a suitable bracket 56 and to the distal end of boom 50 by connection bracket 58 to provide means for pivot-ing the boom 50 from the position generally parallel to tubesheet 14 to the position generally aligned with the manway 24.
~:~3~5~5 47,7ll6 A hollow shaft DC motor 60 is disposed about column 28 and is connected thereto. Motor 60 has a rnotor base 62 with ad~ustable feet 64 which engage the dividing plate 22 to provide means for rotating the column 28 and the boom 50 therewith. Disposed w:ithin the motor 60 are means ~or indicating the angular position of the hollow shaft.
The motor 60 iS reversible to provide rotatlon of column 28 and boom 50 in either direction.
The boom 50 comprises a pair of generally parallel lO rails or channels 66 with guideways 68 disposed on the top - ~;
and bottom portion of each channel 66. The guideways 68 extend longitudinally along the boom 50 and are parallel to each other. A carriage 70 is slidably disposed on the guideways 68 and has a pair of bearings 72 which slidably engage each of the guideways 68 so as to cause the carriage ;
70 to move rectilinearly and parallel to the longitudinal axis of the boom ~0.
The carriage 70, as best shown in Figures 2 and 3, comprises a base 74 and a platform 76 which are disposed ~; `
20 generally parallel to each other and to the tubesheet 14 when the longitudinal axis of the boom 50 is parallel there-to. The base 74 is connected to bearings 72 while the platform 76 is disposed above and parallel to base 74. An ~ ~-air motor 78 or other drive means, is connected to plat~orm 76.
Means for moving platform 76 with respect to base 74 comprises a reversible electric motor 80 or other posi-tioning means for driving a gear train 82. Platform 76 is moved relative to base 74 along a Z axis through gear train 30 82 which comprises two mateable bevel gears 84 and 86, two ` ~3~S~5 47,746 mateable spur gears 88 and 90, worm gear 92, worm wheel .:
94, and threaded sleeve or hollow lead screw 96. ~ear train 82 is best illustrated in Figure 4 which is a partial sectional plan view of the carriage 70 of Figure 2. Worm wheel 94 is driven by worm gear 92 which mates with gear teeth formed on worm wheel 94 ' s exterior. The lnner peri-phery of worm wheel ~4 is machined to mate with lead screw 96 and convert rotary motion imparted to worm wheel. 94 into `
vertical translational movement of lead screw 96. Selective rotation of reversible electric motor 80 provldes a raising and lowering of lead screw 96 and connected platrorm 76. ~
Air motor 78 is supported in lead screw 96 so as to move ~ :
with platform 76 in its upward and downward motions. -~
Means ~or maintaining a parallel relation between base 74 and platform 76 preferably comprises four round bars 98 which are affixed ad~acent the four corners of platform 76 and eight ball bushings 100 disposed in base 74 for slidably receiving bars 98. ~
A cantilevered tool holder 102 is fastened to ; ~.:
20 platform 76 and coupled to air drive motor 78. The canti~
levered tool holder 102, better illustrated in Figure 5, has ~
a tool receptacle or chuck 104 on the distal end thereof for ;~ `
grasping tool 105 and a train of gears or other drive means 106 connecting the drive motor 78 to the tool chuck 104 providing power to drive a tool 105. ;
Ball screw 108, drive motor 110, and ball nut 112 are cooperatively associated with boom 50 and carriage 70 to .
provide means for moving the carriage 70 rectllinearly along ..
the boom 50 and for holding the carriage 70 at any position along the boom 50. The ball screw 108 extends the length of . 1.3~ 1S
47,746 boom 50 and is disposed generally parallel to the longitudinal axis thereof. The ball nut 112 is aff'ixed to the carriage 70 and engages the threads of ball screw 108.
Position indicating means 114 is provided to display the position of carriage 70 along boom 50. A pair (only one ls shown) of hydraulic cylinders 116 which can be extended to contact wall 20 of the head 10 to steady boom 50 when the tool 105 is performing an operation on the tubes 18 or tubesheet 14.
The cantilevered tool holder 102, as best shown in Figure 4, has arcuate plates 118 equally spaced on opposlte sides of the axis of the drive motor 78. Lugs 120 clamp the ~.arcuate plates 118 and tool holder 102 to the platform 76.
Dowels and dowel holes (not shown) are provided in the arcuate plates 118 and in the platform 76 to permit align-ment of the cantilevered tool holder 102 wi.th the axis of boom 50 as shown in Figure 1, rotated 180, or rotated to form an acute angle with respect to the axis of boom 50, as :
shown in phantom in Figure 4. The varying positions of tool .~ .
holder 102 column 28 cooperate to provide access to all the tubes in any selected portion of the tubesheet 14 and estab- -lish accurate positioning of the tool holder 102 to allow remotely controlled repeated operation on any tube 18 in that portion of the tubesheet 14. ; ~A C-shaped stiffening bracket 122 is ~astened to :
the column 28 and spans the motor 60 in order to reduce de-flection o.~ column 28 and minimi~e the forces on the motor 60's bearings.
The apparatus hereinbefore described may be easily and quickly installed in the head 10 of a steam generator 12 -8~
~ 3~ 5~ 47,746 and, with an assortment of tools 105, can perform various operations on all of the tubes 18 in a selected portion of the tubesheet 14 being limited only by dividing plate 22.
The apparatus so structured is rugged and reliable to permit operation within the close tolerances necessary to retube a steam generator utilizing remote controls. To operate re-motely, the angular position of the boom 50 in column 28 must be repeatable. Accurate angular positioning of column 28 and boom 50 and lndications thereof are provided by motor 60 with positional locking of the interconnected column 2 and boom 50 being provided by split collar 36 locking column 28 in the desired angular position.
The carriage 70 is positioned by rotating the ball screw 108 with motor 110 which has a brake disposed therein to lock ball screw 108 in any desired position. Ball screw nut 112 rides on the threads of screw 108 and has a plural-ity of balls which engage the threads thereof. This co-operating combination of screw and nut minimizes backlash allowing precise positioning of the carriage 70 and is not sub~ect to backdriving by the carriage. Thus, when motor llO's brake ls engaged, carriage 70 remains fixed in any desired position.
The hydraulic cylinders 54 which raise boom 50 ~ ~;
from a position aligned with manway 24 to a position where -boom 50 is generally parallel to the tubesheet 14 preferably acts against a stop in the latter position to increase the rigidity of the entire apparatus 26.
It will no~ be apparent that an improved remotely operable repair apparatus has been provided in which a highly compact tool positioning mechanism is utilized to _g_ :
, ~:
- ~13(~5~S ll7, 7ll6 mechanically engage selected tools 105 with tubesheet 14 and tubes 18. The mechanical positioning mechanism's construction results in a structure whose control is precise and whose size permits Or easy entry to the head's interior through the manway 24.
-10- ~`
, . . . ,, , . . .. ~ , .. ,, . ~ . . - . . ...
Claims (10)
1. Apparatus for remotely repairing a tubesheet and tubes accessible from a head of a steam generator which has a centrally disposed partition dividing the head into an inlet and an outlet portion and a manway disposed in each of said portions, said apparatus comprising:
a column rotatably disposed in a portion of said head generally perpendicular to said tubesheet, said column having one end terminating a predetermined distance from said tubesheet;
a boom pivotally mounted adjacent the terminal end of said column;
means for rotating said column and said boom therewith;
means for locking said column and said boom in any rotated position;
means for pivoting said boom from a position generally parallel to said tubesheet to positions generally aligned with each of said manways;
a carriage disposed to ride lengthwise along said boom;
means for moving said carriage lengthwise along said boom and for fixing the position of said carriage on said boom;
said carriage including a base which is generally paral-lel to the tubesheet when the longitudinal axis of the boom is generally parallel to the tubesheet, a platform generally parallel to the base, a first gear train at least partially supported by the base and connected to the platform for moving said platform relative to said base, means for maintaining a parallel relation between the platform and base, a positioning motor for transmitting power to said first gear train, a tool holder supported by and being selectively cantilevered over said platform, said tool holder including a chuck for grasping tools and a drive motor for driving said chuck, said drive motor being associated with said first gear train and being movable with said platform wherein a plurality of tools operable on the tubes and the tubesheet are graspable by the chuck.
a column rotatably disposed in a portion of said head generally perpendicular to said tubesheet, said column having one end terminating a predetermined distance from said tubesheet;
a boom pivotally mounted adjacent the terminal end of said column;
means for rotating said column and said boom therewith;
means for locking said column and said boom in any rotated position;
means for pivoting said boom from a position generally parallel to said tubesheet to positions generally aligned with each of said manways;
a carriage disposed to ride lengthwise along said boom;
means for moving said carriage lengthwise along said boom and for fixing the position of said carriage on said boom;
said carriage including a base which is generally paral-lel to the tubesheet when the longitudinal axis of the boom is generally parallel to the tubesheet, a platform generally parallel to the base, a first gear train at least partially supported by the base and connected to the platform for moving said platform relative to said base, means for maintaining a parallel relation between the platform and base, a positioning motor for transmitting power to said first gear train, a tool holder supported by and being selectively cantilevered over said platform, said tool holder including a chuck for grasping tools and a drive motor for driving said chuck, said drive motor being associated with said first gear train and being movable with said platform wherein a plurality of tools operable on the tubes and the tubesheet are graspable by the chuck.
2. The apparatus as set forth in claim 1, wherein the cantilevered tool holder has means disposed therein for transmitting power from the drive motor to the tool chuck.
3. The apparatus as set forth in claim 2, wherein the means for transmitting power from the drive motor to the tool chuck comprises a second gear train.
4. m e apparatus as set forth in claim 1, wherein the means for rotating said column is a hollow shaft motor.
5. The apparatus as set forth in claim 1, wherein the means for locking said column comprises a split collar with a gap at the split and a hydraulic cylinder which when activated closes the gap and clamps the column.
6. The apparatus as set forth in claim 1, wherein the boom has four guideways disposed thereon generally parallel to the longitudinal axis of the boom and the car-riage has a plurality of bearing pairs which slidably engage each of the guideways.
7. The apparatus as set forth in claim 1, wherein the means for maintaining parallelism between the platform and the base comprise a plurality of bars disposed perpen-dicular to said platform and a plurality of bearings attached to said base and in slidable engagement with said bars.
8. The apparatus as set forth in claim 1, said first gear train comprising a plurality of interconnected gears and power transmission shafts, said gear including an internal-external gear whose internal teeth are engageable with a cylindrical lead screw, said lead screw housing said drive motor and providing platform displacement when rotated.
9. The apparatus as set forth in claim 1, wherein a support is rotatably disposed on an intermediate portion of the column and has means therein which permit adjustment in two directions in a plane generally parallel to the tube-sheet.
10. The apparatus as set forth in claim 1, further comprising: a pivotable support attachable to the lower end of the column and to the head.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA338,846A CA1130545A (en) | 1979-10-31 | 1979-10-31 | Apparatus for remotely repairing tubes in a steam generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA338,846A CA1130545A (en) | 1979-10-31 | 1979-10-31 | Apparatus for remotely repairing tubes in a steam generator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1130545A true CA1130545A (en) | 1982-08-31 |
Family
ID=4115495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA338,846A Expired CA1130545A (en) | 1979-10-31 | 1979-10-31 | Apparatus for remotely repairing tubes in a steam generator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1130545A (en) |
-
1979
- 1979-10-31 CA CA338,846A patent/CA1130545A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |