CA2038174A1 - Means for introducing inspection equipment in active pipelines - Google Patents
Means for introducing inspection equipment in active pipelinesInfo
- Publication number
- CA2038174A1 CA2038174A1 CA002038174A CA2038174A CA2038174A1 CA 2038174 A1 CA2038174 A1 CA 2038174A1 CA 002038174 A CA002038174 A CA 002038174A CA 2038174 A CA2038174 A CA 2038174A CA 2038174 A1 CA2038174 A1 CA 2038174A1
- Authority
- CA
- Canada
- Prior art keywords
- pipeline
- housing
- hole
- pipe
- axis
- 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.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/26—Pigs or moles, i.e. devices movable in a pipe or conduit with or without self-contained propulsion means
- F16L55/46—Launching or retrieval of pigs or moles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L41/00—Branching pipes; Joining pipes to walls
- F16L41/04—Tapping pipe walls, i.e. making connections through the walls of pipes while they are carrying fluids; Fittings therefor
- F16L41/06—Tapping pipe walls, i.e. making connections through the walls of pipes while they are carrying fluids; Fittings therefor making use of attaching means embracing the pipe
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/005—Investigating fluid-tightness of structures using pigs or moles
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
MEANS FOR INTRODUCING INSPECTION EQUIPMENT
IN ACTIVE PIPELINES
ABSTRACT OF THE DISCLOSURE
A method and apparatus for internally inspecting a relatively small diameter live pipeline with a camera introduced into an elongated hole cut into the wall of the pipeline at a strategic location.
A housing formed by a pair of opposed oblique nipples is secured to the pipe and a rotary cutter is operated successively through the nipples to produce the elongated hole. The camera is introduced successively through each of the nipples to scan both upstream and downstream of the location of the elongated hole. The oblique orientation of the nipples simplifies the elongated hole forming operation and reduces flexural stresses on a cable used to propel the camera through the pipeline.
IN ACTIVE PIPELINES
ABSTRACT OF THE DISCLOSURE
A method and apparatus for internally inspecting a relatively small diameter live pipeline with a camera introduced into an elongated hole cut into the wall of the pipeline at a strategic location.
A housing formed by a pair of opposed oblique nipples is secured to the pipe and a rotary cutter is operated successively through the nipples to produce the elongated hole. The camera is introduced successively through each of the nipples to scan both upstream and downstream of the location of the elongated hole. The oblique orientation of the nipples simplifies the elongated hole forming operation and reduces flexural stresses on a cable used to propel the camera through the pipeline.
Description
~3~7~
MEANS P'OR IN'rROl)UCING INSPE:CTION EQUIPMENT
MEANS P'OR IN'rROl)UCING INSPE:CTION EQUIPMENT
2 IN ACq'I'VE PIPELINE:S
3 BAC~GROUND_OF THE INV~NTION
4 The invention relates to methods.and apparatus for in~pecting in-service pipelines.
6 ~RIOR ART
7 In-ser~ice pipelines are subject to corrosion 8 and other forms of damage or degradation. When a 9 pipeline is buried in the earth or otherwise not readily accessible for external visual inspection it is ll known to survey the condition of the pipeline by 12 causing a television camera to travel through the line 13 while the pipeline remains in place and, if conditions 14 permit, while it remains in service. Generally, this television scanning technique has only been most 16 practical where the pipeline to be inspected is 17 relatively large in diameter 50 as to permit p~ssage of 18 a self-propelled camera mounted on traction wheels. It 19 has not been generally practical to in~pect small diameter pipelines internally with a TV camera because 21 of the aifficulty in introducing the camera laterally 22 through the wall of small diameter pipelines and 23 because the limited area of a small pipe does not 24 accommodate the bulk of known traction propelled TV
cameras.
26 SUMMARY OF THE INV~NTION
27 The in~ention provides a method and apparatus 28 for internally inspecting a pipeline while it remains 29 in service and is especially suited for inspecting ` ~3~ 7~
1 buried, small diameter pipe. In accordance with the 2 invention, an access hole is cut into the wall of the 3 pipe at a strategic location. The hole is cut by a 4 tool operating within a fluidtight housing assembled on and sealed with the exterior of the pipeline. The 6 housing includes guide surfaces that support the cutter 7 tool for advance into the wall of the pipe along two 8 separate axii, each oblique to the axis of the pipe and 9 having a directional component along the pipe opposed to that of the other.
11 The cutting tool preferably is a hole saw 12 that rotates and advances succe~aively on each of the 13 separate cutting axii. The hole saw and cutting axii 14 are arranged in the housing to cut an oblong hole in the wall of the pipeline that is considerably longer in 16 the axial direction of the pipe than it is in the 17 transverse direction. The oblong configuration of the 18 hole allows a relatively large elongate TV inspection 19 camera to be inserted into and traverse the pipeline.
In the preferred embodiment of the apparatus, 21 the housing comprises two nipple-like branches that are 22 angled in a common plane radial of the pipe and 23 converge toward~ the wall area to be entered. Gate 24 valves or like means are provided on each branrh nipple to permit entry and withdrawal of the cuttin~ element 26 or elements and, subsequently, inspection apparatus~
27 The branches of the housing are angled in 28 opposed directions with respect to the axis of the pipe 29 and, con~eq~ently, are adapted to support and guide a relati~ely stiff inspection cable through the opening 31 cut in the pipeline successi~ely in opposite directions 32 along the pipe. This capability of the housing for bi-33 directionally supportin~ the inspection cable is o~
34 great importance because it permits inspection of an 203~ 7~
1 extended length of buried pipe through points of entry 2 spaced at distances twice that of t.he working length of 3 the cable. The working length of the cable can be 4 limited by friction between it and the interior walls o~ the pipe and the practical length of communications 6 wire associated with the in~pection camera. Excavation 7 and ~ite preparation time for entry into the pipeline 8 is proportionately reduced.
9 BRIEF D~SCRIPTION OF THE DRAWI W S
10 - FIG. 1 is an elevational mostly cross-11 sectional view o~ an apparatus constructed in 12 accordance with the invention and installed on a 13 pipeline in service;
14 FIG. 2 is a view similar to FIG. 1 illustrating the insertion of an inspection camera 16 device; and 17 FIG. 3 is a view similar to FIGS. 1 and 2 18 illustrating the inspection camera fully recesived in 19 the pipeline and a cable protection device in place.
D~SCRI~TION O~ T~_PR~F~RRED EUBODIMENT
21 A housing 10 is installed at a selected 22 strategic location of a pipeline 16. The illustrated 23 pipeline 16 represents an under~round n~tural gas line 24 of, for example, 3 to 6 inches in siz0. The invention is useful with other types of pipelines and in other 26 environments~ At the site of the installation of the 27 housing 10, the earth is excavated and the e~terior 28 surface of the pipe 16 is cleaned sufficiently to 29 ensure that a fluidtight s0al can be oht~ined between the pipe surfaces and the mating ~urfac~s of the 6~38~7~
- 1 housing 10. The housing 10 includes a pair of hranched 2 nipples 11 and 12 welded or otherwise joined in 3 fluidtight relation to a semi-cylindrical saddle plate 4 13. The housing i5 fabricated fro~ steel parts or other suitable structural materials~ The saddle plate 6 13 has a semi-cylindrical hollow configuration enabling 7 its inside surface designated 14 to ~onform to the 8 exterior surface of the pipeline 16. Hole~ 18 in 9 flanges 19 are provided on each end and each siae of the plate 13 to receive ends of U-bolts 21 which are 11 tightened with associated nuts 22 to draw and hold the 12 saddle plate 13 tightly against the pipeline 16.
13 G~ket material ~not shown) can be interposed between 14 the saddle plate surface 14 and exterior of the pipeline 16 to achieve a fluidtight seal between the~e 16 surfaces.
17 The nipples 11 and 12 are angled towards each 18 other such that their axii lie in a common plane that 19 passes through the coincident axii of the cylindri~al saddle plate 13 and the pipeline 16. The axial 21 direction of each branch nipple 11, 12 has a component 22 along the axii o~ the saddle plate 13 and pipe 16 23 opposite to that of the other nipple so that with 24 respect to the pipe, each branch nipple points in a direction opposite that of the other.
26 ~he branch nipples 11, 12 and ~addle plate 13 27 comprise the principle parts of the housing 10 so that 28 the enclosed space o~ the housing 10 is substantially 29 that enclosed by each nipple 11, 12. On the distal or free end of each nipple 23 is a gate valve 26 of known 31 construction that is operable selectively to close or 32 open ~ull access to the associated nippl~. A threaded 33 bushing 24 can be provided on the threaded distal ends 34 23 of the nipples 11, 12 to allow use Q~ a single pair 2~3317~
1 of gate valves 26 and related hardware on apparatus 2 like the illustrated apparatus but of larger size for 3 larger pipe sizes.
4 The saddle plate 13 has an oblong hole 27 within the space enclosed by the nipples 11, 12. The 6 perimeter of this hole 27 corresponds to the combined 7 projections of the cylindrical internal ~urfaces of the 8 branched nipples 11, 12 on the saddle plate 13. A hot 9 tapping machine 28 of generally known construction is mounted on one of the gate valves 26, for example, by 11 threaded engagement with a bushing 29 threaded into the 12 gate valve 26. The machine 28 is sele~tively operable 13 to rotate and axially displace a ~haft 31 that is 14 coaxial with the axis of the associated nipple 11 or 12. A rotary hole saw 32 is fixed to a free end of the 16 shaft 31. The axial stroke of the shaft 31 is 17 suffi~ient to completely extend and retract the hola 18 saw through the associated nipple 11 or 12 and the 19 associated gate valve 26. In the illustrated embodiment, the hole saw 32 has a diameter close to 21 that of an inside surface 25 of the nipples 11 and 12 22 so that the latter surface can laterally support and 23 guide the hole saw against significant movement radial 24 of the axis of rotation.
When installed, the tapping machine 28 ~eals 26 off the distal end of the nipple when the gate valve 26 27 is open. The tapping machine operates to extena the 28 hole saw 32, mounted on the actuating shaft 31, throu~h 29 the gate valve and saddle plate hole 27 against the wall of the pipe 16. The hole saw or cutter 32, upon 31 rotation, ~uts into the wall of the pipe 16 along a 32 line that corresponds to a proje~tion of the 33 cylindrical outline oE the hole saw on the pipe. The 34 cutter 32 is advanced until it cuts a slot at least to 2~3~-~7~
1 an imaginary plane transverse to the saadle plate axis 2 and bisecting the joint between the branc~hed nipples 11 3 and 12. At this time, the hole saw 32 is withdrawn 4 through the associated gate valve 26 and the gate valve is closed. The hot tapping machine 28 is removed and 6 mounted on the other nipple 11 or 12. With the 7 associated gate valve 26 open the hole ~aw cutter 32 is 8 again extended and rotated to form a se~ond cut into 9 the wall of the pipe 16~ The cutter 32 is advanced until the slot it cut~ meets the first cut slot at the 11 ~ mid-plane between the branched nipples ll and 12.
12 magnet or other means for retaining the coupon cut from 13 the pipe wall can be carried on the cutter or can be 14 inserted through the first branch nipple prior to full separation of the coupon. In accordance with an 16 important aspect of the invention, the branched nipples 17 11, 12 are oriented in a manner that causes the cutter 18 32 to be guided along their respective axii 50 that the 19 resultant hole which it cuts is an oblong hole in the pipe sidewall which has its major dimension, measured 21 along the axial or lengthwi~e direction of the pipe, 22 substantially longer than a holP which could be cut 23 with a single cutter 32 operating in only one branch at 24 the same angle as either of the illustrated branches 11 and 1~
26 With the coupon cut from the pipeline 16, the 27 cutter 32 and hot tapping machine 28 can be removed 28 from the branched nipples 11 and 12. A cylindrical TV
29 inspection camera 36 is inserted into the pipeline through the freshly cut hole designated 37. As shown 31 in FIGS. 2 and 3, the length of the elongated hole 37 32 enables the ~amera 36 to he manipulated into the 33 pipeline 16 de~pite its relative bulk being of a ~4 diameter in the order of about one-half the in~ide `" 2~8~7~
1 diameter of the pipe and being of a length greater than 2 the diametèr of the pipe.
3 The camera 36 is guided by the nipple 11 or 4 ~2 into the pipe]ine 16. The angle~ orient~tion of a branched nipple 11 or 12 allows its internal surface to 6 ~uide the camera 16 and an associated cable 38 smoothly 7 into the pipeline 16 and along the direction the 8 particular branch nipple i~ pointed. FIG. 3 show~ the 9 condition where the camera 36 is fully received through the hole 37 into the pipeline 16. The angular or 11 - oblique orientation of a branched nipple 11 and 12 12 reduces the flexure in the cable 38 necessary to enter 13 the pipeline. The camera 36 is pushed through the 14 pipeline 16 by the cable 38 which is relatively stiff.
As the camera moves, it makes a visual inspection of 16 the interior of the pipeline to detect any signs~of 17 leakage, corrosion, or other dama~e. A ~eries of seals 18 or packing 39 (FIG. 2) prevents significant leakage of 19 fluid from the housing 10 along the cable 38 where it enter~ a bran~hed nipple 11 or 12.
21 A guide bar implement 41 shown in FIG. 3 i~
~2 used to protect the cable 38 from rubhing against an 23 edge of the hole 37 remote from the nipple 11 or 12 24 through which the cable enters the pipe. The guide bar 41 is operated through the opposite nipple 11 or 12 26 from whi~h the cable enters the pipe. An apertured 27 diaphragm or other seal can be provided on the handle 28 of the guide bar to prevent escape of fluid. A lower 29 end 43 of the bar 41 is forked; journalled between the tines of the fork 43 is a cylindrical roller 44 Near 31 the roller 44 is a proje~ting hook 46, fixed to the 32 forked end 43, which i~ manipulated into the hole 37 33 and caught against the interior surface af the pipe 16 34 to positively locate the fork and roller in proper ~3~L7~
1 position. In this position, the cahle 38 passes under 2 the roller 44 betwaen the tines and is held away by the 3 roller from the cut edge of the hole 37 remote from the 4 nipple 11 or 12 through which the cable 38 is bein~
fed~
6 The cable 38 is driven, preferably by a 7 powerwinch, progressively into the ni~ple 1~ or 12.
8 The angled orientation of the nipple relative to the 9 axis of the pipe smoothly guides the cable without exce~sive bending~ The ~amera is propelled axially 11 - alon~ the pipe by a push force exerted through the 12 cable 38. ~he distance that the camara inspection 13 device 36 can be driven is limited by friction forces 14 between the cable 38 and internal pipe surfaces and~or the w~rking length of the communication wires 16 transmitting data from the camera that are integrated 17 with the cable proper. When the camera ha~ reached the 18 limit of its axial excursion in one direction, having 19 visually recorded the condition of the pipe, it is withdrawn with the ca~le from the pipeline. ~ith the 21 gate valves 26 closed, the cable and packing 39 is 22 transferred to the other nipple 11 or 12. The camera 23 is then reintroduced into the pipeline and driven 24 a~ially along the pipe in a direction opposite that of a ~irst phase of inspection.
26 In this manner, a relatively long length of 27 pipe can be inspected by cutting inspection holes 37 28 into the wall of the pipe 16 with the apparatus at 29 distances spaced apart twicè that of the workin~ length of the cable. This is of particular advantag~ where 31 the pipe being inspected is a natural gas line buried 3~ in the earth since a minimum number of a~cavation sites 33 need be established. The angled character of each of 34 the nipple branches 11 and 12 not only permits an 2~3~7~
1 oblong hole ~7 to he readily cut in the wall of the 2 pipe for reception of the elongate camera, but also 3 permits passage of the cable 88 in both axial direction 4 of pipe without severe bendi.ng of the cahle on a relatively small radius.
6 After inspection operations have been 7 completed, the housing 10 can be loosened and slipped 8 axially on a pipe while a permanent split sleeve o~
9 known construction is caused to follow it over the hole 37~ The permanent sleeve is tightened on the pipeline 11 - for a permanent installation and the housing 10 i5 12 removed.
13 It ~hould be e~ident that this disclosure is 14 by way o~ example and that various changes may be made by adding, modifying or eliminating details without 16 departing from the fair scope of the teaching contained 17 in this disclosure. The invention is therefore not 18 limited to particular details of this disclosure except 19 to the extent that the following claims are necessarily so limited.
6 ~RIOR ART
7 In-ser~ice pipelines are subject to corrosion 8 and other forms of damage or degradation. When a 9 pipeline is buried in the earth or otherwise not readily accessible for external visual inspection it is ll known to survey the condition of the pipeline by 12 causing a television camera to travel through the line 13 while the pipeline remains in place and, if conditions 14 permit, while it remains in service. Generally, this television scanning technique has only been most 16 practical where the pipeline to be inspected is 17 relatively large in diameter 50 as to permit p~ssage of 18 a self-propelled camera mounted on traction wheels. It 19 has not been generally practical to in~pect small diameter pipelines internally with a TV camera because 21 of the aifficulty in introducing the camera laterally 22 through the wall of small diameter pipelines and 23 because the limited area of a small pipe does not 24 accommodate the bulk of known traction propelled TV
cameras.
26 SUMMARY OF THE INV~NTION
27 The in~ention provides a method and apparatus 28 for internally inspecting a pipeline while it remains 29 in service and is especially suited for inspecting ` ~3~ 7~
1 buried, small diameter pipe. In accordance with the 2 invention, an access hole is cut into the wall of the 3 pipe at a strategic location. The hole is cut by a 4 tool operating within a fluidtight housing assembled on and sealed with the exterior of the pipeline. The 6 housing includes guide surfaces that support the cutter 7 tool for advance into the wall of the pipe along two 8 separate axii, each oblique to the axis of the pipe and 9 having a directional component along the pipe opposed to that of the other.
11 The cutting tool preferably is a hole saw 12 that rotates and advances succe~aively on each of the 13 separate cutting axii. The hole saw and cutting axii 14 are arranged in the housing to cut an oblong hole in the wall of the pipeline that is considerably longer in 16 the axial direction of the pipe than it is in the 17 transverse direction. The oblong configuration of the 18 hole allows a relatively large elongate TV inspection 19 camera to be inserted into and traverse the pipeline.
In the preferred embodiment of the apparatus, 21 the housing comprises two nipple-like branches that are 22 angled in a common plane radial of the pipe and 23 converge toward~ the wall area to be entered. Gate 24 valves or like means are provided on each branrh nipple to permit entry and withdrawal of the cuttin~ element 26 or elements and, subsequently, inspection apparatus~
27 The branches of the housing are angled in 28 opposed directions with respect to the axis of the pipe 29 and, con~eq~ently, are adapted to support and guide a relati~ely stiff inspection cable through the opening 31 cut in the pipeline successi~ely in opposite directions 32 along the pipe. This capability of the housing for bi-33 directionally supportin~ the inspection cable is o~
34 great importance because it permits inspection of an 203~ 7~
1 extended length of buried pipe through points of entry 2 spaced at distances twice that of t.he working length of 3 the cable. The working length of the cable can be 4 limited by friction between it and the interior walls o~ the pipe and the practical length of communications 6 wire associated with the in~pection camera. Excavation 7 and ~ite preparation time for entry into the pipeline 8 is proportionately reduced.
9 BRIEF D~SCRIPTION OF THE DRAWI W S
10 - FIG. 1 is an elevational mostly cross-11 sectional view o~ an apparatus constructed in 12 accordance with the invention and installed on a 13 pipeline in service;
14 FIG. 2 is a view similar to FIG. 1 illustrating the insertion of an inspection camera 16 device; and 17 FIG. 3 is a view similar to FIGS. 1 and 2 18 illustrating the inspection camera fully recesived in 19 the pipeline and a cable protection device in place.
D~SCRI~TION O~ T~_PR~F~RRED EUBODIMENT
21 A housing 10 is installed at a selected 22 strategic location of a pipeline 16. The illustrated 23 pipeline 16 represents an under~round n~tural gas line 24 of, for example, 3 to 6 inches in siz0. The invention is useful with other types of pipelines and in other 26 environments~ At the site of the installation of the 27 housing 10, the earth is excavated and the e~terior 28 surface of the pipe 16 is cleaned sufficiently to 29 ensure that a fluidtight s0al can be oht~ined between the pipe surfaces and the mating ~urfac~s of the 6~38~7~
- 1 housing 10. The housing 10 includes a pair of hranched 2 nipples 11 and 12 welded or otherwise joined in 3 fluidtight relation to a semi-cylindrical saddle plate 4 13. The housing i5 fabricated fro~ steel parts or other suitable structural materials~ The saddle plate 6 13 has a semi-cylindrical hollow configuration enabling 7 its inside surface designated 14 to ~onform to the 8 exterior surface of the pipeline 16. Hole~ 18 in 9 flanges 19 are provided on each end and each siae of the plate 13 to receive ends of U-bolts 21 which are 11 tightened with associated nuts 22 to draw and hold the 12 saddle plate 13 tightly against the pipeline 16.
13 G~ket material ~not shown) can be interposed between 14 the saddle plate surface 14 and exterior of the pipeline 16 to achieve a fluidtight seal between the~e 16 surfaces.
17 The nipples 11 and 12 are angled towards each 18 other such that their axii lie in a common plane that 19 passes through the coincident axii of the cylindri~al saddle plate 13 and the pipeline 16. The axial 21 direction of each branch nipple 11, 12 has a component 22 along the axii o~ the saddle plate 13 and pipe 16 23 opposite to that of the other nipple so that with 24 respect to the pipe, each branch nipple points in a direction opposite that of the other.
26 ~he branch nipples 11, 12 and ~addle plate 13 27 comprise the principle parts of the housing 10 so that 28 the enclosed space o~ the housing 10 is substantially 29 that enclosed by each nipple 11, 12. On the distal or free end of each nipple 23 is a gate valve 26 of known 31 construction that is operable selectively to close or 32 open ~ull access to the associated nippl~. A threaded 33 bushing 24 can be provided on the threaded distal ends 34 23 of the nipples 11, 12 to allow use Q~ a single pair 2~3317~
1 of gate valves 26 and related hardware on apparatus 2 like the illustrated apparatus but of larger size for 3 larger pipe sizes.
4 The saddle plate 13 has an oblong hole 27 within the space enclosed by the nipples 11, 12. The 6 perimeter of this hole 27 corresponds to the combined 7 projections of the cylindrical internal ~urfaces of the 8 branched nipples 11, 12 on the saddle plate 13. A hot 9 tapping machine 28 of generally known construction is mounted on one of the gate valves 26, for example, by 11 threaded engagement with a bushing 29 threaded into the 12 gate valve 26. The machine 28 is sele~tively operable 13 to rotate and axially displace a ~haft 31 that is 14 coaxial with the axis of the associated nipple 11 or 12. A rotary hole saw 32 is fixed to a free end of the 16 shaft 31. The axial stroke of the shaft 31 is 17 suffi~ient to completely extend and retract the hola 18 saw through the associated nipple 11 or 12 and the 19 associated gate valve 26. In the illustrated embodiment, the hole saw 32 has a diameter close to 21 that of an inside surface 25 of the nipples 11 and 12 22 so that the latter surface can laterally support and 23 guide the hole saw against significant movement radial 24 of the axis of rotation.
When installed, the tapping machine 28 ~eals 26 off the distal end of the nipple when the gate valve 26 27 is open. The tapping machine operates to extena the 28 hole saw 32, mounted on the actuating shaft 31, throu~h 29 the gate valve and saddle plate hole 27 against the wall of the pipe 16. The hole saw or cutter 32, upon 31 rotation, ~uts into the wall of the pipe 16 along a 32 line that corresponds to a proje~tion of the 33 cylindrical outline oE the hole saw on the pipe. The 34 cutter 32 is advanced until it cuts a slot at least to 2~3~-~7~
1 an imaginary plane transverse to the saadle plate axis 2 and bisecting the joint between the branc~hed nipples 11 3 and 12. At this time, the hole saw 32 is withdrawn 4 through the associated gate valve 26 and the gate valve is closed. The hot tapping machine 28 is removed and 6 mounted on the other nipple 11 or 12. With the 7 associated gate valve 26 open the hole ~aw cutter 32 is 8 again extended and rotated to form a se~ond cut into 9 the wall of the pipe 16~ The cutter 32 is advanced until the slot it cut~ meets the first cut slot at the 11 ~ mid-plane between the branched nipples ll and 12.
12 magnet or other means for retaining the coupon cut from 13 the pipe wall can be carried on the cutter or can be 14 inserted through the first branch nipple prior to full separation of the coupon. In accordance with an 16 important aspect of the invention, the branched nipples 17 11, 12 are oriented in a manner that causes the cutter 18 32 to be guided along their respective axii 50 that the 19 resultant hole which it cuts is an oblong hole in the pipe sidewall which has its major dimension, measured 21 along the axial or lengthwi~e direction of the pipe, 22 substantially longer than a holP which could be cut 23 with a single cutter 32 operating in only one branch at 24 the same angle as either of the illustrated branches 11 and 1~
26 With the coupon cut from the pipeline 16, the 27 cutter 32 and hot tapping machine 28 can be removed 28 from the branched nipples 11 and 12. A cylindrical TV
29 inspection camera 36 is inserted into the pipeline through the freshly cut hole designated 37. As shown 31 in FIGS. 2 and 3, the length of the elongated hole 37 32 enables the ~amera 36 to he manipulated into the 33 pipeline 16 de~pite its relative bulk being of a ~4 diameter in the order of about one-half the in~ide `" 2~8~7~
1 diameter of the pipe and being of a length greater than 2 the diametèr of the pipe.
3 The camera 36 is guided by the nipple 11 or 4 ~2 into the pipe]ine 16. The angle~ orient~tion of a branched nipple 11 or 12 allows its internal surface to 6 ~uide the camera 16 and an associated cable 38 smoothly 7 into the pipeline 16 and along the direction the 8 particular branch nipple i~ pointed. FIG. 3 show~ the 9 condition where the camera 36 is fully received through the hole 37 into the pipeline 16. The angular or 11 - oblique orientation of a branched nipple 11 and 12 12 reduces the flexure in the cable 38 necessary to enter 13 the pipeline. The camera 36 is pushed through the 14 pipeline 16 by the cable 38 which is relatively stiff.
As the camera moves, it makes a visual inspection of 16 the interior of the pipeline to detect any signs~of 17 leakage, corrosion, or other dama~e. A ~eries of seals 18 or packing 39 (FIG. 2) prevents significant leakage of 19 fluid from the housing 10 along the cable 38 where it enter~ a bran~hed nipple 11 or 12.
21 A guide bar implement 41 shown in FIG. 3 i~
~2 used to protect the cable 38 from rubhing against an 23 edge of the hole 37 remote from the nipple 11 or 12 24 through which the cable enters the pipe. The guide bar 41 is operated through the opposite nipple 11 or 12 26 from whi~h the cable enters the pipe. An apertured 27 diaphragm or other seal can be provided on the handle 28 of the guide bar to prevent escape of fluid. A lower 29 end 43 of the bar 41 is forked; journalled between the tines of the fork 43 is a cylindrical roller 44 Near 31 the roller 44 is a proje~ting hook 46, fixed to the 32 forked end 43, which i~ manipulated into the hole 37 33 and caught against the interior surface af the pipe 16 34 to positively locate the fork and roller in proper ~3~L7~
1 position. In this position, the cahle 38 passes under 2 the roller 44 betwaen the tines and is held away by the 3 roller from the cut edge of the hole 37 remote from the 4 nipple 11 or 12 through which the cable 38 is bein~
fed~
6 The cable 38 is driven, preferably by a 7 powerwinch, progressively into the ni~ple 1~ or 12.
8 The angled orientation of the nipple relative to the 9 axis of the pipe smoothly guides the cable without exce~sive bending~ The ~amera is propelled axially 11 - alon~ the pipe by a push force exerted through the 12 cable 38. ~he distance that the camara inspection 13 device 36 can be driven is limited by friction forces 14 between the cable 38 and internal pipe surfaces and~or the w~rking length of the communication wires 16 transmitting data from the camera that are integrated 17 with the cable proper. When the camera ha~ reached the 18 limit of its axial excursion in one direction, having 19 visually recorded the condition of the pipe, it is withdrawn with the ca~le from the pipeline. ~ith the 21 gate valves 26 closed, the cable and packing 39 is 22 transferred to the other nipple 11 or 12. The camera 23 is then reintroduced into the pipeline and driven 24 a~ially along the pipe in a direction opposite that of a ~irst phase of inspection.
26 In this manner, a relatively long length of 27 pipe can be inspected by cutting inspection holes 37 28 into the wall of the pipe 16 with the apparatus at 29 distances spaced apart twicè that of the workin~ length of the cable. This is of particular advantag~ where 31 the pipe being inspected is a natural gas line buried 3~ in the earth since a minimum number of a~cavation sites 33 need be established. The angled character of each of 34 the nipple branches 11 and 12 not only permits an 2~3~7~
1 oblong hole ~7 to he readily cut in the wall of the 2 pipe for reception of the elongate camera, but also 3 permits passage of the cable 88 in both axial direction 4 of pipe without severe bendi.ng of the cahle on a relatively small radius.
6 After inspection operations have been 7 completed, the housing 10 can be loosened and slipped 8 axially on a pipe while a permanent split sleeve o~
9 known construction is caused to follow it over the hole 37~ The permanent sleeve is tightened on the pipeline 11 - for a permanent installation and the housing 10 i5 12 removed.
13 It ~hould be e~ident that this disclosure is 14 by way o~ example and that various changes may be made by adding, modifying or eliminating details without 16 departing from the fair scope of the teaching contained 17 in this disclosure. The invention is therefore not 18 limited to particular details of this disclosure except 19 to the extent that the following claims are necessarily so limited.
Claims (8)
1. A method of inspecting a live pipeline comprising the steps of attaching a fluidtight housing on the pipeline, using a rotary cutter operating in the housing to cut a hole in the side of the pipeline, the cutter being supported in the housing to cut an elongated hole, with the major axis of the hole substantially aligned with the axial direction of the pipeline, inserting an elongated inspection device through the elongated hole, axially advancing the inspection device along the pipe by pushing it with a cable fed into the pipeline through the housing.
2. A method as set forth in claim 1, wherein the elongated hole is cut with a circular hole saw rotated about an axis oblique to the axis of the pipeline.
3. A method as set forth in claim 2, wherein the cable enters the housing along a line generally coincident with the axis of rotation of the cutter.
4. A method as set forth in claim 2, wherein the elongated hole is formed by successive operations of a circular hole saw rotating about two axes each oblique to the axis of the pipe and converging towards one another.
5. A method as set forth in claim 4, wherein the axes of rotation are arranged to produce a hole greater in length in the axial direction of the pipe than a hole which could be produced by the same cutter operating along only one axis.
6. A method as set forth in claim 5, wherein the housing is provided in the form of two converging branches corresponding to said axes of rotation, and the inspection device is introduced into the pipeline successively through a first and then a second of said branches, the pipe being inspected in one axial direction when the inspection device is inserted in the first branch and being inspected in the opposite direction when the inspection device is inserted in the second branch.
7. Apparatus for inspecting a pipeline in service comprising a housing adapted to he fixed on the exterior of the pipeline to isolate a portion of its wall from the environment, rotary cutter means receivable in the housing, means on the housing for supporting said rotary cutter means for rotation and advance into the isolated wall portion on two separate cutting axii, each of said axii and the longitudinal axis of the pipe lying in substantially the same plane, the separate cutting axii each forming an oblique angle with the axis of the pipe and being arranged such that movement along each towards the pipeline includes a directional component opposite that of the other, valving means associated with each axis of the housing, said rotary cutter supporting means including actuator means carried by said housing outwardly of said valving means, the actuator means having a shaft for rotating and axially advancing said rotary cutter means successively along each of said cutting axii, said cutting axii and rotary cutter means being arranged to cut a hole in the side of the pipeline that is elongated in the axial direction of the pipeline and is greater in length in such direction than a hole which could be cut by said cutter means operating along only one of said axii whereby a relatively bulky elongated camera can be fully received in said pipeline through the elongated hole.
8. Apparatus as set forth in claim 7 including cable guide means insertable through said housing into the elongated hole to protect a cable trailing said inspection camera from an edge of the elongated hole.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US530,224 | 1990-05-30 | ||
| US07/530,224 US5025670A (en) | 1990-05-30 | 1990-05-30 | Means for introducing inspection equipment in active pipelines |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2038174A1 true CA2038174A1 (en) | 1991-12-01 |
Family
ID=24112899
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002038174A Abandoned CA2038174A1 (en) | 1990-05-30 | 1991-03-13 | Means for introducing inspection equipment in active pipelines |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US5025670A (en) |
| CA (1) | CA2038174A1 (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2128619C (en) * | 1992-07-17 | 1998-09-22 | Joseph R. Carapezza | Centralizer for internal pipe inspection device |
| US5823115A (en) * | 1994-09-09 | 1998-10-20 | British Gas Plc | Guiding of a pipe travelling device |
| GB2301646B (en) * | 1995-04-04 | 1998-09-16 | British Gas Plc | Apparatus for introducing into and removing from a pipe a device which is advanced and retracted by a cable |
| US5612499A (en) * | 1995-05-05 | 1997-03-18 | Tdw Delaware, Inc. | Method of inserting a sensor into a pipeline |
| WO1997014911A1 (en) * | 1995-10-16 | 1997-04-24 | Siemens Aktiengesellschaft | Process and device for introducing a self-propelled 'mouse' into a pipe |
| CA2294605C (en) | 1997-06-26 | 2005-04-12 | Gas Research Institute | System for inspecting in-service gas distribution mains |
| GB2335742B (en) * | 1998-03-23 | 2002-07-10 | British Gas Plc | Fluid pressure testing |
| CA2568450C (en) * | 2004-05-28 | 2013-03-26 | Pii Pipetronix Gmbh | Method, device and tool for cleaning, measuring, inspecting or similar non-piggable pipelines |
| US7551197B2 (en) * | 2005-09-08 | 2009-06-23 | Ulc Robotics, Inc. | Pipeline inspection system |
| GB2447038B (en) * | 2006-11-21 | 2011-05-25 | Oswald Peter John Meli | Pipe connections |
| GB2460470A (en) * | 2008-05-31 | 2009-12-02 | P N Daly Ltd | Inclined access assembly for a pipeline |
| GB2468301B (en) * | 2009-03-03 | 2013-06-12 | Jd7 Ltd | Water mains inspection and servicing |
| GB2469286A (en) * | 2009-04-07 | 2010-10-13 | Brian Beech | Internal inspection apparatus for pipes |
| GB2520688B (en) * | 2013-11-27 | 2019-05-01 | E M & I Maritime Ltd | Apparatus and method for inspecting flooded cavities in a floating offshore installation |
| KR101550674B1 (en) | 2015-04-22 | 2015-09-08 | 수자원기술 주식회사 | Diagnosis System of Small-diameter Pipe and Method thereof |
| EP3106735A1 (en) * | 2015-06-19 | 2016-12-21 | ULC Robotics, Inc. | Launch system for a pressurized pipeline |
| JP7068009B2 (en) * | 2018-04-05 | 2022-05-16 | コスモ工機株式会社 | Pipeline cutting method |
| US20190376632A1 (en) * | 2018-06-06 | 2019-12-12 | Hydra-Stop Llc | Under-pressure tapping and access assembly for pressurized pipe |
| CN112161146B (en) * | 2020-08-27 | 2022-04-12 | 中国石油工程建设有限公司 | Shared pigging connecting device and shared pipeline |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US997464A (en) * | 1910-07-25 | 1911-07-11 | Charles W Metcalf | Device for tapping and controlling the flow of liquids in pipes. |
| US3703909A (en) * | 1971-07-14 | 1972-11-28 | Hurtsteel Products Ltd | Drilling apparatus |
| US4067353A (en) * | 1976-09-28 | 1978-01-10 | Amp Incorporated | Pipeline tap and connecting device |
| DE3111814A1 (en) * | 1981-03-25 | 1982-10-07 | Kraftwerk Union AG, 4330 Mülheim | SELF-DRIVING TUBE MANIPULATOR FOR REMOTE CONTROLLED TRANSPORTATION OF TEST EQUIPMENT AND TOOLS LENGTH'S SPECIFIC FEED TRACKS, PREFERRED FOR NUCLEAR POWER PLANTS |
| US4546789A (en) * | 1983-03-31 | 1985-10-15 | Taylor Robert R | Valved access fitting |
| US4649948A (en) * | 1984-11-14 | 1987-03-17 | Leak Detective, Inc. | Entry tap valve for pressurized pipe leak detector |
-
1990
- 1990-05-30 US US07/530,224 patent/US5025670A/en not_active Expired - Fee Related
-
1991
- 1991-03-13 CA CA002038174A patent/CA2038174A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US5025670A (en) | 1991-06-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |