CA1044050A - Device for backing butt-welds between tubes - Google Patents
Device for backing butt-welds between tubesInfo
- Publication number
- CA1044050A CA1044050A CA244,143A CA244143A CA1044050A CA 1044050 A CA1044050 A CA 1044050A CA 244143 A CA244143 A CA 244143A CA 1044050 A CA1044050 A CA 1044050A
- Authority
- CA
- Canada
- Prior art keywords
- strip
- refractory material
- support strip
- tubes
- tubular members
- 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
- 239000011819 refractory material Substances 0.000 claims abstract description 71
- 230000002093 peripheral effect Effects 0.000 claims abstract description 22
- 230000007246 mechanism Effects 0.000 claims abstract description 15
- 230000004927 fusion Effects 0.000 claims abstract description 10
- 238000003466 welding Methods 0.000 claims abstract description 10
- 230000033001 locomotion Effects 0.000 claims description 27
- 239000011230 binding agent Substances 0.000 claims description 4
- 239000010954 inorganic particle Substances 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 2
- 230000008093 supporting effect Effects 0.000 claims 2
- 239000012530 fluid Substances 0.000 claims 1
- 239000002184 metal Substances 0.000 abstract description 4
- 229910052751 metal Inorganic materials 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 16
- 230000000717 retained effect Effects 0.000 description 5
- 235000004443 Ricinus communis Nutrition 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 241001432959 Chernes Species 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 208000002352 blister Diseases 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Landscapes
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
ABSTRACT
A device used during fusion butt-welding between the ends of tubular members to form a backing for the weld inside the tubular members. The device comprises a thin flexible metal support strip having end portions which are overlapped to provide an arcuate outer peripheral surface which can be changed in cir-cumference, and a mechanism for increasing the peripheral circumference of the support strip. For use, a strip of refractory material is secured on the periphery of the support strip, the device is positioned with the strip of refractory material adjacent the inner surfaces of and bridging the ends of tubular members to be welded, and the mechanism is activated to press the strip of refrac-tory material into engagement with the tubular members.
A device used during fusion butt-welding between the ends of tubular members to form a backing for the weld inside the tubular members. The device comprises a thin flexible metal support strip having end portions which are overlapped to provide an arcuate outer peripheral surface which can be changed in cir-cumference, and a mechanism for increasing the peripheral circumference of the support strip. For use, a strip of refractory material is secured on the periphery of the support strip, the device is positioned with the strip of refractory material adjacent the inner surfaces of and bridging the ends of tubular members to be welded, and the mechanism is activated to press the strip of refrac-tory material into engagement with the tubular members.
Description
J
DEVICE FOR BACKING BUTT-WELDS BETWEEN TUBES ~
. . :.
This invention relates to devices which provide a backing inside tubes during fusion butt-welding between ends of the tubesO
During fusion butt-welding between the ends of two tube~ it i9 often necessary or desirable to provide a backlng around the inner surfaces of the tubes adjacent and bridging their butted ends to dam the molten metal caused by the welding process. An efficient backing means can form an inner surface on the weld which requires little if any cleaning or finishing to provide a suitable inner surface between the joined tubesO .
One type of prior art device for providing such a backing comprises a plurality of firm backing members ;
(typically arcuate copper faced bars) and means for moving ~ .
the backing members from a release position spaced from the inner surfaces of the tubes, to an engaged position with the backing members forcefully pressed against the inner `-surfaces of the tubes to be butt-welded. Such devices are suggested in U.S. Letters Patent No'sO 2,413,103; 2~987,022;
20 3,369,725; 3,498,518; 3,741,457; and 3,806,0200 Typically these devlces are quite expensive and do not provide as :
high a degree of ad;ustability to accommodate tubes of various inside diameters ~e.gO pipe of the same outside diameter but of different wall thickness) or tubes which 25 are out of round. The rigid backing members w~ll not conform to rough inner surfaces so that surface irreg~-~larities may space the outer surface of one or more of the backing members from the inner surface of the tubes and ~ ~r ~ "
~4~V~
.~ allow excessive intrusion of the molten weld material lnto the joined tubesO Also the backing members occaslonally adhere to the weld and interfere with the removal of the device.
It is also well known in the prior art to use a steel rlng to provide a backing for fusion butt-welds -between the ends of cylindrical tubes. The steel ring is selected to have an outside diameter of about the same size as the inside diameter of the tubes, and a sufficient peripheral width to bridge between the ends of the tubes The molten weld material adheres to the ring, however, and removal of such a ring, i~ necessary, requires grinding it ~.
out of the pipe, which is expensive and time consumingO
U.SO Letters Patent No. 3,372,851 teaches using a strip of a flexible, deformable, refractory material comprising inorganic particles bound together with a flexible organic binder as a backing for fusion butt-weldsO
This refractory material provides an effective and efficient backing, however, applying the refractory material through the use of an adhesive coated strip, as taught in that patent, is not always possible or as convenient as may be desired for applying the refractory material around the inner surfaces of butted tubesO
UcSO Patents No'sO 2,792,626 and 3,460,736 suggest devices for pressing a strip o~ backing material into engagement with the inner surfaces of two butted tubes to be butt weldedO These devices, however, do not provide the degree o~ adjustability required for tubes of various `
sizes~ Also they do not provide the proper type of .
support for the friable refractory material taught 1.n
DEVICE FOR BACKING BUTT-WELDS BETWEEN TUBES ~
. . :.
This invention relates to devices which provide a backing inside tubes during fusion butt-welding between ends of the tubesO
During fusion butt-welding between the ends of two tube~ it i9 often necessary or desirable to provide a backlng around the inner surfaces of the tubes adjacent and bridging their butted ends to dam the molten metal caused by the welding process. An efficient backing means can form an inner surface on the weld which requires little if any cleaning or finishing to provide a suitable inner surface between the joined tubesO .
One type of prior art device for providing such a backing comprises a plurality of firm backing members ;
(typically arcuate copper faced bars) and means for moving ~ .
the backing members from a release position spaced from the inner surfaces of the tubes, to an engaged position with the backing members forcefully pressed against the inner `-surfaces of the tubes to be butt-welded. Such devices are suggested in U.S. Letters Patent No'sO 2,413,103; 2~987,022;
20 3,369,725; 3,498,518; 3,741,457; and 3,806,0200 Typically these devlces are quite expensive and do not provide as :
high a degree of ad;ustability to accommodate tubes of various inside diameters ~e.gO pipe of the same outside diameter but of different wall thickness) or tubes which 25 are out of round. The rigid backing members w~ll not conform to rough inner surfaces so that surface irreg~-~larities may space the outer surface of one or more of the backing members from the inner surface of the tubes and ~ ~r ~ "
~4~V~
.~ allow excessive intrusion of the molten weld material lnto the joined tubesO Also the backing members occaslonally adhere to the weld and interfere with the removal of the device.
It is also well known in the prior art to use a steel rlng to provide a backing for fusion butt-welds -between the ends of cylindrical tubes. The steel ring is selected to have an outside diameter of about the same size as the inside diameter of the tubes, and a sufficient peripheral width to bridge between the ends of the tubes The molten weld material adheres to the ring, however, and removal of such a ring, i~ necessary, requires grinding it ~.
out of the pipe, which is expensive and time consumingO
U.SO Letters Patent No. 3,372,851 teaches using a strip of a flexible, deformable, refractory material comprising inorganic particles bound together with a flexible organic binder as a backing for fusion butt-weldsO
This refractory material provides an effective and efficient backing, however, applying the refractory material through the use of an adhesive coated strip, as taught in that patent, is not always possible or as convenient as may be desired for applying the refractory material around the inner surfaces of butted tubesO
UcSO Patents No'sO 2,792,626 and 3,460,736 suggest devices for pressing a strip o~ backing material into engagement with the inner surfaces of two butted tubes to be butt weldedO These devices, however, do not provide the degree o~ adjustability required for tubes of various `
sizes~ Also they do not provide the proper type of .
support for the friable refractory material taught 1.n
-2-, ~1344~35C~
UOSO Patent NoO 3,372,851 while the device is being : positioned in butted tubes to be welded, since the device of UOSO Patent NoO 3,460,736 does not maintain an arcuate periphery when not positioned ln a tube, and the device m of UOSo Patent NoO 2,792,626 maintains the strip of backing material too closely adJacent the inner surface of the tubes to preclude contact therebetweenO
The present invention comprises a device includ-ing the flexible, deformable, refractory material taught in UOS~ Patent No. 3,372,851 to provide an inexpensive backing ;~ ~
for fuslon butt-welds between the ends of tubesO The back- - -ing provided is adaptable to a relatively large range of :
inner tube diameters and will closely conform to the inner ~.:
surfaces of both round and out of round tubes, even where 15 there is a high degree of sur~ace roughness within the . :
tubes O
According to the present invention there is provided a device for use during fusion butt-weldlng between the ends Or two tubular members having similar curvilinear inner surfacesO The device is of the known type comprising a backing structure having a contact sur- .
face adapted to contact and bridge between the inner ..
surfaces of the tubular members in which the backing structure is adapted for movement between a retracted position with the contact surface spaced from the inner ~urface of the tubular members and an engage position with the contact sur~ace pressed against the inner surfaces of the tubular members, and the device includes a mechanism for moving the backing structure from its retracted to lts engaged positionO In the device according to the present S~ .
invention the backing structure comprises a thln flexible support strip having overlapped end portions to provide an arcuate outer peripheral sur~ace, and structure guiding the overlapplng end portions for relatlve longi~udinal sliding movement to change the peripheral circum~erence of said support stripO Also included is a strip of flexible refracto.ry material comprlsing inorganic particles bound together with a flexible organic binder adapted to have a length dimension which is about the same as that of the inner circumference of the tubular members, and structure adaptedfor securing the strip of refractory material on the periphery of the support strip so that the sur~ace of the refractory material opposite the perlphery of the support strip provides the contact surface for the deviceO The mechanlsm for moving the backing structure increases the perlpheral circumference o~ the support strlp to press the strip of refractory material into engagement with the inner surfaces of the butted tubesO
For use, the circum~erence of the support strip is decreased by sliding the end portions to increase th~
overlap therebetween, the strip of refractory material is secured on the support strip with its ends overlapped over the overlapped end portions of the support strip, the assembly is positioned inside two butted tubes -with the strip of refractory material ad~acent and bridging the butted ends thereof, and the circumference of the support strip is increased and positioned to press the strip of refractory materlal into ~irm engagement with the inner ~-:
surfaces of the butted tubesO
The support ~trip i5 sufficiently flexible to 4V56~
COn~Qrm to curvllinear inside diameters o~ the tubes even ~ .
if the tubes are oval or somewhat out of round~ and the deformable strip o~ refractory material will form around - surface roughness under the influence of moderate pressure : 5 to posltion the strip of refractory material agalnst the lnside su.rfaces of the tubes and limit intrusion of the molten weld materlal into the tubesO
.. . . .
The mechanism for increasing the circumference of ~.
the strip to press the strip of refractory material into .
10 engagement with the internal sur~aces of tubes may be pro- ..
vided by a manually operated device such as a bolt or over ~.
center device between the end portions of the stripO How- ~ :
ever, where the device is to be used on tubes cf var~ous inside dlameters it is preferable to use springs or air expanded members to increase the circumference of the device D ` ' ' The present invention will be further described with re~erence to the accompanying drawing whereln like numbers refer to like parts in the several. views and wherein:
Figure 1 is a vertical end view of a ~irst embodiment of a device according to the present invention .including a strip of refractory material being pressed into ;, .
internal engagement between the butted ends of a pair of tube~ to be fusion welded;
Figure 2 is a sectional view taken approximately along the line 2-2 of Figure l; --Figure 3 ~s a sectional view taken approximatel~ -along the line 3-3 of Figure l;
30Figure 4 1R a perspe~.tive view o~ a se~ond -5- :.
embodiment of the device according to the present invention;
Figure 5 is a vertical sectional view illustrating the device of ~igure 4 positioned wlthin two tubes between which a fu~ion butt-weld is to be formed;
Figure 6 is a sectional view taken approximately - along the line 6-6 of Figure 5;
Figure 7 is a perspectlve view with parts broken away to show detail of a third alternate embodiment of the device according to the present invention;
Figure 8 is a perspective view of a fourth embodl-ment of the device according to the present invention;
Figure 9 is a vertical side view of the device of Figure 8;
Figure 10 is an enlarged fragmentary vlew of the :. 15 device of Figure 8 positioned within two tubes between which a rusion butt-weld i8 to be formed;
Flgure 11 is a sectlonal view taken approximately .
along the line 11-11 of Flgure 9; and Figure 12 is an enlarged fragmentary view o~ a ; 20 clip for securing and guiding a strip of refractory material included in the device.
Re~erring now to Figures 1 through 3 of the drawing, there is illustrated a flrst embodiment Or a device accordlng to the present inv~ntion, generally designated by the numeral 10. The device 10 lncludes a backing 8trip of deformable, flexible refractory material 13 forcefully positioned against and bridging the inner surfaces of a pair of tubes or pipes 11 in a positlon to serve as a backing during fusion butt-welding between the ends of the tubes 11.
: ,....... . . . . . . .. . .
,0 : The preferred refractory material comprises lnorganlc particles bound together with a flexible organic binder and is that refractory material taught in UOSO Patent No. 3,372,851, the content whereof is incorporated herein by reference.
The device 10 comprises a thin, flexible support : strip 12 (eOgO 5 centimeter (2 inch) wide 0.09 cm (20 gauge~
thick full hard stainless steel shim stock~ having first and æecond end portions 14 and 16 respectively which are over- .
lapped to provide an arcuate outer peripheral surface 18 on which the strip of refractory material 13 is supported.
The terminal end of the first end portion 14 is wider than the second end portion 16 and carries a flange 20 disposed radlally inwardly from the first end portion 140 The flange 20 is formed with a slot 22 through which the second end portion 16 is slidably retained inwardly of the first ~;
end portion 14, and which with a pair of tabs 24 on the first end portion 14 bent around the edges of the second end portion 16 provide structure guiding the overlapping first and second end portions 14 and 16 for relative slid-ing movementO Such sliding movement change~ the peripheral circumference of the support strip 12 by changing the amount of overlap between the first And second end portions 14 and 16 thereof~
A pair of sprlngs 25 are tensioned between the flange 20 and a slmilar inwardly pro~ecting flange 26 at - :
the end of the second end portion 16~ The springs 25 bias the end portions 14 and 16 to increase the peripheral cir- -cumference of the support strip 12 and with overlapped end portions 14 and 16 provide a mechanism for pressing the ;~&~4~5~
:; strlp of refractory material 13 into engagement with the inner surfaces o~ the tubes llo The backing strip 12 is sufficiently flexible to conform to cylindrical or arcuate inner surfaces aga~nst which the strip of refractory mater-lal 13 is pressed under the influence of the springs 25.
The strip of flexible refractory material 13 is secured on the periphery of the support strip 12 by struc-ture comprising a plurality of tongs 27 cut from the support strip 12. The tongs 27 pro~ect above the peripheral surface of the support strip 12 and press into and locate the edges of the strlp of refractory material 13. Addi-tionally, or alternatively, the structure for securing the :
strip Or refractory material 13 could comprise a length of double coated adhesive tape between the support strlp 12 and the strip of refractory material 130 The device 10 also includes a plurallty o~ spacedlocating pins 29 which, as is shown in Figures 2 and 3, can be removably mounted in sockets 30 staked through the sup-port strip 12 so that the pins 29 will pro~ect radially of the s~pport strip 12 through and from positions centralLy located between the edges of the strip of refractory material 130 The diameter of the locating pins 29 provides a predetermined spacing between the ends of the tubes 11 to :
be butt-weldedO A trigger pin 32 (shown removed in Fig-ure 2) has a diameter similar to that of the locating pins 29 and an end 33 removably engageable ln two aligned openings of a plurality of openings 34 in the overlapped end portions 14 and 16 of the support strip 12 to retain a predetermined overlapped condltion therebetween against the influence Qf the springs 25 -8~
~ L~5~
To use the device 10, an operator attaches to .
the outer peripheral surface 18 a strlp of the refractory material 13 having a length about the same as the inner circumference of the tubes 11 in which the device 10 is to ~ .
be used. One end of the strip of refractory material 13 is positioned at the flange 20 on the first end portion 140 :.
The operator manually moves the flanges 20 and 26 away from each other against the bias of the springs 25 to approp.ri-ately decrease the peripheral circumference of the device 10, and laps the end of the strip of refractory material 13 ; opposite that attached at the flange 20 outwardly over the -~
attached end. The device 10 is then in a retracted posi-tion which affords movement of the device through the tubes 11 with the strip of refractory material 13 spaced from the inner surface of the tubes 11.
If the device 10 is to be used without the :. `
locatlng pins 29 or tr~gger pin 32, the operator manually retains the flanges 20 and 26 while he positions the device 10 through an end of one of the tubes 11 with the strip of re~ractory material 13 ad~acent the ad~oining ends of the tubes llo He then releases the flanges 20 and 26 so that the springs 25 expand the circumference of the device 10 to move it to an engage position at which the strip of refractory material 13 is pressed against the inner sur-faces of the tubes 11 at and bridging their adjoining endsO
If the device 10 is to be used with thelocating pins 29, the operator presses the end 33 of the trigger pin 32 through the strip of refractory material 13 ~;
and two aligned openings 31~ in the end portions 14 and 16 to retain the end portlons 14 and 16 ~gainst the springs 25 44~
in the retracted position of the device 10; and presses - locating pins 29 t,hrough the strip of refractory material 13 and into the sockets 30~ One end of the device 10 is then inserted into the end to be welded of one of the tubes 11 until the pins 29 and 32 engage the end of that tube Llo The end to be welded of the ot;her tube 11 is positioned around the other end of the device 10 until it also engages the plns 29 and 320 With the device 10 thus positioned via :
the pins 29 and 32 between the ends of two tubes 11, the operator then pulls the tr~gger pin 32~ causing the springs 25 to move the support strip 12 to its engage position with the strip of refractory material 13 pressed against the inner surfaces of the tubes 11. The locating pins 29 may then be removedO
The fusion weld can then be made between the ends ' of the tubes llo The heat of welding reduces the backing strip to a residue similar to coffee groundsO After the weld is complete the device 10 is removed and the residue ` :
is brushed from the pipe, leaving the weld with a well-20 formed, clean inner surfaceO ;~
Figures 4 through 6 illustrate a second embodiment , of a device according to the present invention, generally designated by the numeral 360 The device 36 is particularly useful where the lengths of the tubes 38 to be butt-welded , 25 are such, or the adjoining ends of the tubes to be butt- ` ~
welded are so positioned or retained that the device 10 may ,:.,:
not be manually positioned by either of the methods indi-cated aboveO '-The deYice 36 lncludes a cart-like portlon adapted to move axially along the lnner surface of tubes 38 , ~4~5~ ~ ~
to be joined and carry a portion of the device similar to the devlce 10 which is movable relative to the cart-llke portion from a retracted position to an engage position In the retracted position a strip of refractory material 40 included in the movable portion is coiled to afford move-ment of the device 36 through the tubes wlth the strip of material 40 spaced from the inner surface of the tubes 38 in which the device 36 is located and positioning of the str~p of refractory material 40 adjacent the butted ends of 10 the tubes 30. In the engage position the strip of refrac- ~.
tory material 40 is pressed against the inner surfaces of the tubes at and bridging their butted ends. `
Like the device 10, the device 36 comprises a .
thin, flexible support strip 41 having first and second end 15 portions 42 and 43 respectively which are overlapped to provide an outer peripheral surface 44 on which the st:rip ; of refractory material 40 is supported. The terminal end of the first end portion 42 carries a slotted inwardly pro-~ecting flange 45 through which the second end portion 43 ! 20 is slidably retained, and which together with a pair of tabs 46 on the first end portion 42 (which are curved ;.
around the edges of the second end portion 43) provide structure for guiding the overlapping first and second end portions 42 and 43 for relative sliding movement to change 25 the peripheral circumference of the support strip 41O
A pair of springs 47 tensioned between khe flange 45 and a similar ~nwardly projecting flange 48 at the end of the second end portion 43 bias the end portions 42 and 43 to increase the peripheral circumference of the 30 support str~p 41 and press the strip of refractory -11- ';
:- - . . ; . .- ~ , - . . . .
material 13 into engagement with the inner surfaces of . the tubes 38.
Like the end portions 14 and 16 of the device 10, the end portions 42 and 43 each have a plurality of spaced 5 openings 49 two of which can be aligned and engaged by a removable pin 50 inserted from inslde the support strlp 41 to retain a predetermined overlapped condltion between the end portions 42 and 43 against the influence of the springs 47.
The cart-like portion comprises a generally .
rectangular frame 51 having wheels 52 at its corners adapted to contact the inner surface of a tube~ and a central section of reduced width about which the support strip 41 is supported. The frame 51 has a threaded 15 socket 53 adapted to receive the end of a rod 54 used in ~
pushing or pulling the device 36 through a tube. ~;
The support strip 41 is supported on the frame 51 `` :: .
by a rectangular movable member 56 attached at one end to one portion of the support strip 41 and slidably mounted in 20 a guide 57 on the frame 51 for movement radially of the ;.:
support strip 41 to move said one portion thereof from a spaced position (Figures 4 and 5) with the portion of the ;-strip of refractory material 40 on said one portion of the support strip 41 spaced from the inner surface of tubes 38 25 in which the device 36 is located, and a contact position with said backing strip portion contacting the inner sur- , face of the tubes 38 (Flgure 6) . -A pair of spring~ 58 are attached between the frame 51 and the ends of a shaft 59 fixed to the movable member 56 and guided for sliding movement in slots in the vs(~
guide 57. The springs 58 bias the movable member toward the contact positionO A pin 60 is engageable through a hole -.
in a pro~ection 61 on the movable member 56 which pro~ects through an opening in the guide 57 when said portion of the 5 strip of refractory materlal 41 is in its spaced position ;
to releasably retain it there.
A support arm 63 is fixed to the guide 57 and has ends each with two projecting fingers 64 spaced to slidably engage opposite edges of the support strip 41 to position the same while allowing movement thereof between the fingers 64 to afford relative sliding movement of the end portions 42 and 43 and corresponding changes in the periph- .
eral circumference of the support strip 41.
To use the device 36~ an operator spreads the : 15 flanges 45 and 48 against the bias of the springs 47 to a desired circumference for the support strip 41 which will :
permit free movement of a strip of refractory material 40 thereabout through the tubes 38 in which the device 36 is to be used, and then inserts the pin 50 in a pair of aligned holes in the overlapped end portions 42 and 43 to retain the desired circumferenceO A strip of refractory material 40 of the desired length is attached on the ~ :
periphery of the support strip 41 with the ends of the strip of refractory material 40 overlapped at the ~uncture between the end portions 42 and 43 of the support strip 41 (See Flgure 4). Also, the operator moves the movable member 56 to the spaced position for the refractory mater-ial 40 and retains it there by inserting the pin 60o The movable portion of the device 36 is then in its retracted positionO
.
. , ~l~4~
.`' Next the device 36 is pushed into the tubes 38 via the rod 54 which may be calibrated or marked to show - the proper positionlng for the device 36 with the strip of re~ractory material 40 adjacent the abutted ends of the tubes 38 to be welded togetherO
After such posltio~ing is achieved the operator .
pulls a cord 66 which is attached to the pins 50 and 60 to first pull the pin 60 and allow the movable member 56 to move the refractory material 40 to the contact`position, and then to pull the pin 50 to allow the springs 47 to expand the support strip 41 and press the strip of refrac~
tory material 40 into engagement with the butted ends of the tubes 38. The movable portion of the device is then in its engage position so that the tubes 38 can be weldedO
15 Where the device 36 is to be used in vertical or almost vertical tubes, the frame may also include removable -.
pro~ections 67 (shown in dotted outline in Figure 5), each .
of which slidably supports a castor wheel 68 outwardly biased by a spring 690 The castor wheels 68 provide means for maintaining the wheels 52 against the inner surface of a vertical or almost vertical tube in which the device 36 is positioned, while the spring mounting of the castor ;
wheels 68 afford movement of the device 36 over irregu-larities in the tube~
Figure 7 illustrates yet a third embodiment of a device according to the present invention, generally desig- .
nated by the numeral 70, which like the device 36 is particularly useful in situations where the device 10 ma~
not be manually positioned at the adJoining ends of tubes to be wel.dedO
Like the device 36, the device 70 comprises a cart-like portion adapted to move axially along the inner surface of tubes to be ~oined. The cart-like portion carries a portion o~ the device which is movable relative to the cart-like portion from a retracted position with a strip of refractory material 71 coiled to afford movement of the device 70 through the tubes with the strip of mater-ial 40 spaced from the inner surface of the tubes and positioning of the strip of refractory material 71 adjacent ;10 the butted ends of the tubes; to an engage posltion with the strip of refractory material 71 pressed against the ;
inner surfaces of the tubes at and bridging their butted ends.
The mechanism for moving the strip o~ refractory ;15 material from its retracted to its engage position com-prises a resilient elastic generally cylindrical member 72 ;(e.g. rubber) having its ends in air tight engagement with the outer edges of a pair of spaced flanges 73 on a ridged spool-like support 74O The space between the resilient cylindrical member 72 and the spool-like support 74 pro-vides a chamber 75 coupled to a source of air under greater than atmospheric pressure through an inlet hose 77 to expand the resilient cylindrical member 72 and thereby increase its peripheral circum~erence. A device having a structure similar to the combination of the spool-like support 74 and the elastic cylindrical member 72 is com-mercially available in various sizes from Cherne Industrial, Inc., 5701 South County Road 18, Edina, Minnesota, 55436, as the "Muni~Ball Plug~o A thin, flexible, resilient~ spring metal support ~J~
. . .
striP 76 iS disposed about the resilient cylindrical member 72. The support strip 76 has first and second end :
portions 78 and 79 respectively which are overlapped to `
. provide a varlable length outer peripheral surface 81 on ` .
which the backing strip 71 is supportedO The support strip 76 is retained against axial movement along the ~.
cylindrical member 72 and its end portions 78 and 79 are . Ouided for relative longitudinal sliding movement by annular . ridges 83 on the cylindrical member 72 flanking the support 10 strlp 76~ .:
` Tbe support strip 76 provides a heat barrier ;:
between the strip of refractory material 71 and the cylin~
drical member (which barrier may be increased by an asbestos layer on the inner surface of the support strip 76 if ~: . - , .
.: 15 necessary) and its use also prevents separation of the ~
, .: .
friable strip of refractory material 71.
The support strip 76 has spring temper biasing ~ .
its end portions 78 and 79 toward a greater overlapped con- .
dition to retain the support strip 76 around the cyllndrical `
20 member 72 when the cylindrical member 72 contracts upon :~
release of air pressure from within the chamber 75.
The cart-like portion of the device 70 comprises .
the spool-like support member 74, and two frame members 84 projecting from opposite ends thereof on which are rotat-ably mounted wheels 86 adapted to contact the inner surface of a tube ln which the device 70 is used. One end of the ;
spool-like support member 74 has a central threaded ~.
socket 87 adapted to receive the end of a rod 88 used in .
pushing or pulling the devlce 70 through a tube~ .
During use of the device 70, the cylindrical .. . ..
- 16 - .
. .`.: `
' member 72 is at first contracted. An operator attaches a strip of refractory material 71 of the desired length on the periphery of the support strip 76 (as by double coated adhesive tape) with its ends overlapped at the juncture between the end portions 78 and 79 of the support strip 76. The device 70 is then pushed into one of the tubes via the rod 88 until the strip of refractory material 71 is ad~acent the abutted ends of the tubes. Then the operator applies air under greater than atmospheric 10 pressure through the hose 77 to move the strip of refrac- :~
tory material 71 to its engage position, The tubes can then be welded.
: Where the device 70 is to be used in vertical or almost vertical tubes, pro~ections like the pro;ec-tions 67 for the device 36 may be addedO
Figures 8 through 12 illustrate a fourth embodiment of a device according to the present inven-tion, generally designated by the numeral 90. Like the devlces 36 an 70, the device 90 is also particu- -~
larly useful in situations where a person cannot reach the inside surfaces of-tubes at their butted ends to ;
position a device such as the device 10. ~ :
Like the devices 36 and 70, the device 90 comprises a cart-like portion adapted to move :
axially along the lnner surface of a pair of tubes 108 to be butt-weldedO The cart-like portlon carries a portion of the device which is movable relative to the cart-like portion from a retracted positlon with a strip of refractory materlal 91 coiled about it to afford movement of the device 90 through . I . ~
. . . . .
the tubes with the strip of refractory material 91 spaced from the inner surface of the tubes and positioning of the strip of refractory material 91 adjacent the butted ends of the tubes; to an engage position with the strip of 5 refractory mater~al 91 pressecL against the inner sur~aces :~
of the tubes bridging their butted ends In the device 90 the mechanism for moving the strip of refractory material from its retracted to its -:~
engage position comprises two resilient elastic generally ~
10 cylindrlcal members 92 (eOg. rubber). Each of the tubular . ~ .
members 92 has its ends clamped in air tight engagement with the conically tapered outer edges of a pair of spaced : ~.
flanges 93 ~lxed on a central ridged hollow cylindrical support tube 94 by conically tapered inner surfaces on a pair of end caps 95 tensioned toward each by a plurallty of bolts 96. The spaces enclosed by the resilient cylin-drical members 92 the flanges 93 and the support tube 94 provide chambers 97 which may be coupled to a source o~
air under greater than atmospheric pressure through an inlet hose 98 and a hose 99 between the chambers 97 to expand the resilient cylindrical members 92 and thereby :
increase their peripheral circumferenceO
A thin, flexible, resilient, spring metal support strip 100 is disposed about and bridges between adjacent ``
25 portions of the resilient cylindrical members 920 The -;
support strip 100 has first and second end portions 101 and 102 respectlvely which are overlapped to provide a variable , ~ '' length outer peripheral surface 103 on which the strip of refractory material 91 is supported. The support strip 96 is retained against axial movement along the cyllndrical ,:
;
-members 92 and its end portions 101 and 102 are guided for relative longitudinal sliding movement by annular ridges 104 molded on the cyllndrical members 92 and flanking the sup- -port strip 100.
The portion of the support strip 100 supportlng :~
the strip of refractory mater'Lal 91 is spaced from the ~ :
cylindrical members 92 to insure that heat ~rom the welding process wlll not damage or rupture the cylindrical mem-bers 92.
The support strip 100 has spring temper biasing its end portions 101 and 102 toward a greater overlapped condition to retain the support strip 100 around the cylindrical members 92 when the cylindrical members 92 contract upon release of air pressure from within the chambers 97c Also to insure such contraction, the device 90 includes two elastic cords 105 tensloned around opposite ends of the support strip 100 between looped ends engaged with pins 106 on the first end portion 101.
The cart-like portion of the device 90 comprises the support tube 94, and two end plates 110 coaxially attached by the bolts 96 to the adjacent flange 93 at opposite ends of the support tube 94. Three wheels 111 are rotatably mounted on each end plate 110 by a mechanism that affords positioning of the wheels 111 at various positions wlth each wheel 111 about equal distance from the axis of the elastic cylindrical members 92 and support strip 96 and aligned for rolling engagement with the inner surface of a pair of tubes tsuch as the tubes 108 shown ln Figures 10 and 11) to coaxially support the device 90 within the tubes and to afford movement of the devlce 90 . . ~
' ~
axially of the tubes. ~ .
The mechanisms mounting the wheels 111 each com-prise a rod 113 mounted for a~ial sliding movement in a . bearing 114 coaxially fixed through one of the end plates .
110. A washer 115 is fixed at the inboard end of the rod 113 and is biased away from the end plate 110 by a coil ` :
spring 116 therebetween. At the other end of the rod 113 `~
is fixed a pivot block 118 on which are pivotably mounted three arms 119 disposed at about 120 degree intervals circumferentially of the pivot block 118, with each of the arms 119 rotatably carrying one of the wheels 111 at its :~
outboard endO A link 120 is pivotably mounted between the center of each of the arms 119 and the housing for the bearing 114 through the end plate 110. The spring 116 blases the pivot block 118 toward the end plate 110 and :
thereby the wheels 111 radially outwardly of the device 90 ~' to an outermost position established by engagement of an ad~usting nut 121 on the rod 113 with the housing of the bearing 114, and the wheels 111 may be moved radially inwardly of the device 90 againsS the bias of the spring 116 to conform the circle defined by the wheels to the inner ;
circumference of a pair of tubes (such as the tubes 108) and afford movement of the wheels 111 over irregularities within the tubes The device 90 is also adapted to grip the inner :~
surface of a pair of butted tubes (such as the tubes 101 shown in Figures 10 and 11), at positions spaced from the strip of refractory material 91 when the strip of refrac~
tory material 91 is in its engage pos~tion so that the strip of refractory material 91 will not move relative to -20- :
', ;' '. .' -the tubes during the welding operation. This is particu-larly advantageous when the tubes are rotated during weldlng.
A portion 122 of each cyllndrical member 92 5 between the adjacent end plate 110 and edge of the support strip 100 is exposed around the periphery of the device 90.
When the cylindrical members 92 are expanded by introducing air under greater than atmospheric pressure into the cham- -bers 97, these exposed portions 122 of the cylindrical 10 members 92 balloon out beyond the periphery of the support strip 100 and engage the inner surfaces of the tubes. Such engagement insures that the device 90 will move with the tubes if the tubes are moved during the welding operation. r The device 90 also includes structure for 15 securing and aligning the consumable backing strip of refractory material 91 in a predetermined position around the support strip 100, and for maintaining such alignment or the backing strip 91 is moved from its retracted to its engage posltions. As is best seen in Figure 12, this 20 structure includes a generally U-shaped clip 123 having a central attaching portion 124 fixed to the support strip 100 adjacent its second end portion 102, and two guide por-tions 125 projecting from opposite edges of the attaching portion 124. The attachlng portion 124 has a row of teeth 127 pro~ecting away from the guide portions 125 and adapted to engage and hold one end of the strip of refrac-tory material 91. Also included are a plurality of cylindrical posts 129 spaced in two rows around the periphery of the support strip 100 with the two rows spaced a~ially of the support strip 100 tc aiford , -, . ~ . . - , , ., ~ 4~
;' ;;.
positioning a portion of the strlp of refractory materlal 91 therebetween after its end is engaged with the teeth 127.
The guide portlons 125 are spaced to receive the free end o~
the strlp of refractory material 91 therebetween over its end attached to the teeth 127 after the portion of the refractory materlal 91 therebetween has been wrapped around the support strip lOOo When the support strip 100 expands to move the strip of refractory material 91 to lts engage position, the free end of the strip of refractory material 10 91 slides over its attached end. During such sllding move- ;
ment, the guide portions 125 guide movement of the free end of the strip of refractory material 91 to insure that lt ~i remains in proper alignment for engagement with the tubes across their butted ends. The guide portions 125 have a spring temper so that they can be resillently compressed by engagement with the inner surfaces of the tubesO The posts 129 have a predetermined length to prevent air pres- ~
sure from within the cylindrical members from compressing -the strlp material more than a predetermined desired amount. -: ,. , :':
~ ~ .
;
.
UOSO Patent NoO 3,372,851 while the device is being : positioned in butted tubes to be welded, since the device of UOSO Patent NoO 3,460,736 does not maintain an arcuate periphery when not positioned ln a tube, and the device m of UOSo Patent NoO 2,792,626 maintains the strip of backing material too closely adJacent the inner surface of the tubes to preclude contact therebetweenO
The present invention comprises a device includ-ing the flexible, deformable, refractory material taught in UOS~ Patent No. 3,372,851 to provide an inexpensive backing ;~ ~
for fuslon butt-welds between the ends of tubesO The back- - -ing provided is adaptable to a relatively large range of :
inner tube diameters and will closely conform to the inner ~.:
surfaces of both round and out of round tubes, even where 15 there is a high degree of sur~ace roughness within the . :
tubes O
According to the present invention there is provided a device for use during fusion butt-weldlng between the ends Or two tubular members having similar curvilinear inner surfacesO The device is of the known type comprising a backing structure having a contact sur- .
face adapted to contact and bridge between the inner ..
surfaces of the tubular members in which the backing structure is adapted for movement between a retracted position with the contact surface spaced from the inner ~urface of the tubular members and an engage position with the contact sur~ace pressed against the inner surfaces of the tubular members, and the device includes a mechanism for moving the backing structure from its retracted to lts engaged positionO In the device according to the present S~ .
invention the backing structure comprises a thln flexible support strip having overlapped end portions to provide an arcuate outer peripheral sur~ace, and structure guiding the overlapplng end portions for relatlve longi~udinal sliding movement to change the peripheral circum~erence of said support stripO Also included is a strip of flexible refracto.ry material comprlsing inorganic particles bound together with a flexible organic binder adapted to have a length dimension which is about the same as that of the inner circumference of the tubular members, and structure adaptedfor securing the strip of refractory material on the periphery of the support strip so that the sur~ace of the refractory material opposite the perlphery of the support strip provides the contact surface for the deviceO The mechanlsm for moving the backing structure increases the perlpheral circumference o~ the support strlp to press the strip of refractory material into engagement with the inner surfaces of the butted tubesO
For use, the circum~erence of the support strip is decreased by sliding the end portions to increase th~
overlap therebetween, the strip of refractory material is secured on the support strip with its ends overlapped over the overlapped end portions of the support strip, the assembly is positioned inside two butted tubes -with the strip of refractory material ad~acent and bridging the butted ends thereof, and the circumference of the support strip is increased and positioned to press the strip of refractory materlal into ~irm engagement with the inner ~-:
surfaces of the butted tubesO
The support ~trip i5 sufficiently flexible to 4V56~
COn~Qrm to curvllinear inside diameters o~ the tubes even ~ .
if the tubes are oval or somewhat out of round~ and the deformable strip o~ refractory material will form around - surface roughness under the influence of moderate pressure : 5 to posltion the strip of refractory material agalnst the lnside su.rfaces of the tubes and limit intrusion of the molten weld materlal into the tubesO
.. . . .
The mechanism for increasing the circumference of ~.
the strip to press the strip of refractory material into .
10 engagement with the internal sur~aces of tubes may be pro- ..
vided by a manually operated device such as a bolt or over ~.
center device between the end portions of the stripO How- ~ :
ever, where the device is to be used on tubes cf var~ous inside dlameters it is preferable to use springs or air expanded members to increase the circumference of the device D ` ' ' The present invention will be further described with re~erence to the accompanying drawing whereln like numbers refer to like parts in the several. views and wherein:
Figure 1 is a vertical end view of a ~irst embodiment of a device according to the present invention .including a strip of refractory material being pressed into ;, .
internal engagement between the butted ends of a pair of tube~ to be fusion welded;
Figure 2 is a sectional view taken approximately along the line 2-2 of Figure l; --Figure 3 ~s a sectional view taken approximatel~ -along the line 3-3 of Figure l;
30Figure 4 1R a perspe~.tive view o~ a se~ond -5- :.
embodiment of the device according to the present invention;
Figure 5 is a vertical sectional view illustrating the device of ~igure 4 positioned wlthin two tubes between which a fu~ion butt-weld is to be formed;
Figure 6 is a sectional view taken approximately - along the line 6-6 of Figure 5;
Figure 7 is a perspectlve view with parts broken away to show detail of a third alternate embodiment of the device according to the present invention;
Figure 8 is a perspective view of a fourth embodl-ment of the device according to the present invention;
Figure 9 is a vertical side view of the device of Figure 8;
Figure 10 is an enlarged fragmentary vlew of the :. 15 device of Figure 8 positioned within two tubes between which a rusion butt-weld i8 to be formed;
Flgure 11 is a sectlonal view taken approximately .
along the line 11-11 of Flgure 9; and Figure 12 is an enlarged fragmentary view o~ a ; 20 clip for securing and guiding a strip of refractory material included in the device.
Re~erring now to Figures 1 through 3 of the drawing, there is illustrated a flrst embodiment Or a device accordlng to the present inv~ntion, generally designated by the numeral 10. The device 10 lncludes a backing 8trip of deformable, flexible refractory material 13 forcefully positioned against and bridging the inner surfaces of a pair of tubes or pipes 11 in a positlon to serve as a backing during fusion butt-welding between the ends of the tubes 11.
: ,....... . . . . . . .. . .
,0 : The preferred refractory material comprises lnorganlc particles bound together with a flexible organic binder and is that refractory material taught in UOSO Patent No. 3,372,851, the content whereof is incorporated herein by reference.
The device 10 comprises a thin, flexible support : strip 12 (eOgO 5 centimeter (2 inch) wide 0.09 cm (20 gauge~
thick full hard stainless steel shim stock~ having first and æecond end portions 14 and 16 respectively which are over- .
lapped to provide an arcuate outer peripheral surface 18 on which the strip of refractory material 13 is supported.
The terminal end of the first end portion 14 is wider than the second end portion 16 and carries a flange 20 disposed radlally inwardly from the first end portion 140 The flange 20 is formed with a slot 22 through which the second end portion 16 is slidably retained inwardly of the first ~;
end portion 14, and which with a pair of tabs 24 on the first end portion 14 bent around the edges of the second end portion 16 provide structure guiding the overlapping first and second end portions 14 and 16 for relative slid-ing movementO Such sliding movement change~ the peripheral circumference of the support strip 12 by changing the amount of overlap between the first And second end portions 14 and 16 thereof~
A pair of sprlngs 25 are tensioned between the flange 20 and a slmilar inwardly pro~ecting flange 26 at - :
the end of the second end portion 16~ The springs 25 bias the end portions 14 and 16 to increase the peripheral cir- -cumference of the support strip 12 and with overlapped end portions 14 and 16 provide a mechanism for pressing the ;~&~4~5~
:; strlp of refractory material 13 into engagement with the inner surfaces o~ the tubes llo The backing strip 12 is sufficiently flexible to conform to cylindrical or arcuate inner surfaces aga~nst which the strip of refractory mater-lal 13 is pressed under the influence of the springs 25.
The strip of flexible refractory material 13 is secured on the periphery of the support strip 12 by struc-ture comprising a plurality of tongs 27 cut from the support strip 12. The tongs 27 pro~ect above the peripheral surface of the support strip 12 and press into and locate the edges of the strlp of refractory material 13. Addi-tionally, or alternatively, the structure for securing the :
strip Or refractory material 13 could comprise a length of double coated adhesive tape between the support strlp 12 and the strip of refractory material 130 The device 10 also includes a plurallty o~ spacedlocating pins 29 which, as is shown in Figures 2 and 3, can be removably mounted in sockets 30 staked through the sup-port strip 12 so that the pins 29 will pro~ect radially of the s~pport strip 12 through and from positions centralLy located between the edges of the strip of refractory material 130 The diameter of the locating pins 29 provides a predetermined spacing between the ends of the tubes 11 to :
be butt-weldedO A trigger pin 32 (shown removed in Fig-ure 2) has a diameter similar to that of the locating pins 29 and an end 33 removably engageable ln two aligned openings of a plurality of openings 34 in the overlapped end portions 14 and 16 of the support strip 12 to retain a predetermined overlapped condltion therebetween against the influence Qf the springs 25 -8~
~ L~5~
To use the device 10, an operator attaches to .
the outer peripheral surface 18 a strlp of the refractory material 13 having a length about the same as the inner circumference of the tubes 11 in which the device 10 is to ~ .
be used. One end of the strip of refractory material 13 is positioned at the flange 20 on the first end portion 140 :.
The operator manually moves the flanges 20 and 26 away from each other against the bias of the springs 25 to approp.ri-ately decrease the peripheral circumference of the device 10, and laps the end of the strip of refractory material 13 ; opposite that attached at the flange 20 outwardly over the -~
attached end. The device 10 is then in a retracted posi-tion which affords movement of the device through the tubes 11 with the strip of refractory material 13 spaced from the inner surface of the tubes 11.
If the device 10 is to be used without the :. `
locatlng pins 29 or tr~gger pin 32, the operator manually retains the flanges 20 and 26 while he positions the device 10 through an end of one of the tubes 11 with the strip of re~ractory material 13 ad~acent the ad~oining ends of the tubes llo He then releases the flanges 20 and 26 so that the springs 25 expand the circumference of the device 10 to move it to an engage position at which the strip of refractory material 13 is pressed against the inner sur-faces of the tubes 11 at and bridging their adjoining endsO
If the device 10 is to be used with thelocating pins 29, the operator presses the end 33 of the trigger pin 32 through the strip of refractory material 13 ~;
and two aligned openings 31~ in the end portions 14 and 16 to retain the end portlons 14 and 16 ~gainst the springs 25 44~
in the retracted position of the device 10; and presses - locating pins 29 t,hrough the strip of refractory material 13 and into the sockets 30~ One end of the device 10 is then inserted into the end to be welded of one of the tubes 11 until the pins 29 and 32 engage the end of that tube Llo The end to be welded of the ot;her tube 11 is positioned around the other end of the device 10 until it also engages the plns 29 and 320 With the device 10 thus positioned via :
the pins 29 and 32 between the ends of two tubes 11, the operator then pulls the tr~gger pin 32~ causing the springs 25 to move the support strip 12 to its engage position with the strip of refractory material 13 pressed against the inner surfaces of the tubes 11. The locating pins 29 may then be removedO
The fusion weld can then be made between the ends ' of the tubes llo The heat of welding reduces the backing strip to a residue similar to coffee groundsO After the weld is complete the device 10 is removed and the residue ` :
is brushed from the pipe, leaving the weld with a well-20 formed, clean inner surfaceO ;~
Figures 4 through 6 illustrate a second embodiment , of a device according to the present invention, generally designated by the numeral 360 The device 36 is particularly useful where the lengths of the tubes 38 to be butt-welded , 25 are such, or the adjoining ends of the tubes to be butt- ` ~
welded are so positioned or retained that the device 10 may ,:.,:
not be manually positioned by either of the methods indi-cated aboveO '-The deYice 36 lncludes a cart-like portlon adapted to move axially along the lnner surface of tubes 38 , ~4~5~ ~ ~
to be joined and carry a portion of the device similar to the devlce 10 which is movable relative to the cart-llke portion from a retracted position to an engage position In the retracted position a strip of refractory material 40 included in the movable portion is coiled to afford move-ment of the device 36 through the tubes wlth the strip of material 40 spaced from the inner surface of the tubes 38 in which the device 36 is located and positioning of the str~p of refractory material 40 adjacent the butted ends of 10 the tubes 30. In the engage position the strip of refrac- ~.
tory material 40 is pressed against the inner surfaces of the tubes at and bridging their butted ends. `
Like the device 10, the device 36 comprises a .
thin, flexible support strip 41 having first and second end 15 portions 42 and 43 respectively which are overlapped to provide an outer peripheral surface 44 on which the st:rip ; of refractory material 40 is supported. The terminal end of the first end portion 42 carries a slotted inwardly pro-~ecting flange 45 through which the second end portion 43 ! 20 is slidably retained, and which together with a pair of tabs 46 on the first end portion 42 (which are curved ;.
around the edges of the second end portion 43) provide structure for guiding the overlapping first and second end portions 42 and 43 for relative sliding movement to change 25 the peripheral circumference of the support strip 41O
A pair of springs 47 tensioned between khe flange 45 and a similar ~nwardly projecting flange 48 at the end of the second end portion 43 bias the end portions 42 and 43 to increase the peripheral circumference of the 30 support str~p 41 and press the strip of refractory -11- ';
:- - . . ; . .- ~ , - . . . .
material 13 into engagement with the inner surfaces of . the tubes 38.
Like the end portions 14 and 16 of the device 10, the end portions 42 and 43 each have a plurality of spaced 5 openings 49 two of which can be aligned and engaged by a removable pin 50 inserted from inslde the support strlp 41 to retain a predetermined overlapped condltion between the end portions 42 and 43 against the influence of the springs 47.
The cart-like portion comprises a generally .
rectangular frame 51 having wheels 52 at its corners adapted to contact the inner surface of a tube~ and a central section of reduced width about which the support strip 41 is supported. The frame 51 has a threaded 15 socket 53 adapted to receive the end of a rod 54 used in ~
pushing or pulling the device 36 through a tube. ~;
The support strip 41 is supported on the frame 51 `` :: .
by a rectangular movable member 56 attached at one end to one portion of the support strip 41 and slidably mounted in 20 a guide 57 on the frame 51 for movement radially of the ;.:
support strip 41 to move said one portion thereof from a spaced position (Figures 4 and 5) with the portion of the ;-strip of refractory material 40 on said one portion of the support strip 41 spaced from the inner surface of tubes 38 25 in which the device 36 is located, and a contact position with said backing strip portion contacting the inner sur- , face of the tubes 38 (Flgure 6) . -A pair of spring~ 58 are attached between the frame 51 and the ends of a shaft 59 fixed to the movable member 56 and guided for sliding movement in slots in the vs(~
guide 57. The springs 58 bias the movable member toward the contact positionO A pin 60 is engageable through a hole -.
in a pro~ection 61 on the movable member 56 which pro~ects through an opening in the guide 57 when said portion of the 5 strip of refractory materlal 41 is in its spaced position ;
to releasably retain it there.
A support arm 63 is fixed to the guide 57 and has ends each with two projecting fingers 64 spaced to slidably engage opposite edges of the support strip 41 to position the same while allowing movement thereof between the fingers 64 to afford relative sliding movement of the end portions 42 and 43 and corresponding changes in the periph- .
eral circumference of the support strip 41.
To use the device 36~ an operator spreads the : 15 flanges 45 and 48 against the bias of the springs 47 to a desired circumference for the support strip 41 which will :
permit free movement of a strip of refractory material 40 thereabout through the tubes 38 in which the device 36 is to be used, and then inserts the pin 50 in a pair of aligned holes in the overlapped end portions 42 and 43 to retain the desired circumferenceO A strip of refractory material 40 of the desired length is attached on the ~ :
periphery of the support strip 41 with the ends of the strip of refractory material 40 overlapped at the ~uncture between the end portions 42 and 43 of the support strip 41 (See Flgure 4). Also, the operator moves the movable member 56 to the spaced position for the refractory mater-ial 40 and retains it there by inserting the pin 60o The movable portion of the device 36 is then in its retracted positionO
.
. , ~l~4~
.`' Next the device 36 is pushed into the tubes 38 via the rod 54 which may be calibrated or marked to show - the proper positionlng for the device 36 with the strip of re~ractory material 40 adjacent the abutted ends of the tubes 38 to be welded togetherO
After such posltio~ing is achieved the operator .
pulls a cord 66 which is attached to the pins 50 and 60 to first pull the pin 60 and allow the movable member 56 to move the refractory material 40 to the contact`position, and then to pull the pin 50 to allow the springs 47 to expand the support strip 41 and press the strip of refrac~
tory material 40 into engagement with the butted ends of the tubes 38. The movable portion of the device is then in its engage position so that the tubes 38 can be weldedO
15 Where the device 36 is to be used in vertical or almost vertical tubes, the frame may also include removable -.
pro~ections 67 (shown in dotted outline in Figure 5), each .
of which slidably supports a castor wheel 68 outwardly biased by a spring 690 The castor wheels 68 provide means for maintaining the wheels 52 against the inner surface of a vertical or almost vertical tube in which the device 36 is positioned, while the spring mounting of the castor ;
wheels 68 afford movement of the device 36 over irregu-larities in the tube~
Figure 7 illustrates yet a third embodiment of a device according to the present invention, generally desig- .
nated by the numeral 70, which like the device 36 is particularly useful in situations where the device 10 ma~
not be manually positioned at the adJoining ends of tubes to be wel.dedO
Like the device 36, the device 70 comprises a cart-like portion adapted to move axially along the inner surface of tubes to be ~oined. The cart-like portion carries a portion o~ the device which is movable relative to the cart-like portion from a retracted position with a strip of refractory material 71 coiled to afford movement of the device 70 through the tubes with the strip of mater-ial 40 spaced from the inner surface of the tubes and positioning of the strip of refractory material 71 adjacent ;10 the butted ends of the tubes; to an engage posltion with the strip of refractory material 71 pressed against the ;
inner surfaces of the tubes at and bridging their butted ends.
The mechanism for moving the strip o~ refractory ;15 material from its retracted to its engage position com-prises a resilient elastic generally cylindrical member 72 ;(e.g. rubber) having its ends in air tight engagement with the outer edges of a pair of spaced flanges 73 on a ridged spool-like support 74O The space between the resilient cylindrical member 72 and the spool-like support 74 pro-vides a chamber 75 coupled to a source of air under greater than atmospheric pressure through an inlet hose 77 to expand the resilient cylindrical member 72 and thereby increase its peripheral circum~erence. A device having a structure similar to the combination of the spool-like support 74 and the elastic cylindrical member 72 is com-mercially available in various sizes from Cherne Industrial, Inc., 5701 South County Road 18, Edina, Minnesota, 55436, as the "Muni~Ball Plug~o A thin, flexible, resilient~ spring metal support ~J~
. . .
striP 76 iS disposed about the resilient cylindrical member 72. The support strip 76 has first and second end :
portions 78 and 79 respectively which are overlapped to `
. provide a varlable length outer peripheral surface 81 on ` .
which the backing strip 71 is supportedO The support strip 76 is retained against axial movement along the ~.
cylindrical member 72 and its end portions 78 and 79 are . Ouided for relative longitudinal sliding movement by annular . ridges 83 on the cylindrical member 72 flanking the support 10 strlp 76~ .:
` Tbe support strip 76 provides a heat barrier ;:
between the strip of refractory material 71 and the cylin~
drical member (which barrier may be increased by an asbestos layer on the inner surface of the support strip 76 if ~: . - , .
.: 15 necessary) and its use also prevents separation of the ~
, .: .
friable strip of refractory material 71.
The support strip 76 has spring temper biasing ~ .
its end portions 78 and 79 toward a greater overlapped con- .
dition to retain the support strip 76 around the cyllndrical `
20 member 72 when the cylindrical member 72 contracts upon :~
release of air pressure from within the chamber 75.
The cart-like portion of the device 70 comprises .
the spool-like support member 74, and two frame members 84 projecting from opposite ends thereof on which are rotat-ably mounted wheels 86 adapted to contact the inner surface of a tube ln which the device 70 is used. One end of the ;
spool-like support member 74 has a central threaded ~.
socket 87 adapted to receive the end of a rod 88 used in .
pushing or pulling the devlce 70 through a tube~ .
During use of the device 70, the cylindrical .. . ..
- 16 - .
. .`.: `
' member 72 is at first contracted. An operator attaches a strip of refractory material 71 of the desired length on the periphery of the support strip 76 (as by double coated adhesive tape) with its ends overlapped at the juncture between the end portions 78 and 79 of the support strip 76. The device 70 is then pushed into one of the tubes via the rod 88 until the strip of refractory material 71 is ad~acent the abutted ends of the tubes. Then the operator applies air under greater than atmospheric 10 pressure through the hose 77 to move the strip of refrac- :~
tory material 71 to its engage position, The tubes can then be welded.
: Where the device 70 is to be used in vertical or almost vertical tubes, pro~ections like the pro;ec-tions 67 for the device 36 may be addedO
Figures 8 through 12 illustrate a fourth embodiment of a device according to the present inven-tion, generally designated by the numeral 90. Like the devlces 36 an 70, the device 90 is also particu- -~
larly useful in situations where a person cannot reach the inside surfaces of-tubes at their butted ends to ;
position a device such as the device 10. ~ :
Like the devices 36 and 70, the device 90 comprises a cart-like portion adapted to move :
axially along the lnner surface of a pair of tubes 108 to be butt-weldedO The cart-like portlon carries a portion of the device which is movable relative to the cart-like portion from a retracted positlon with a strip of refractory materlal 91 coiled about it to afford movement of the device 90 through . I . ~
. . . . .
the tubes with the strip of refractory material 91 spaced from the inner surface of the tubes and positioning of the strip of refractory material 91 adjacent the butted ends of the tubes; to an engage position with the strip of 5 refractory mater~al 91 pressecL against the inner sur~aces :~
of the tubes bridging their butted ends In the device 90 the mechanism for moving the strip of refractory material from its retracted to its -:~
engage position comprises two resilient elastic generally ~
10 cylindrlcal members 92 (eOg. rubber). Each of the tubular . ~ .
members 92 has its ends clamped in air tight engagement with the conically tapered outer edges of a pair of spaced : ~.
flanges 93 ~lxed on a central ridged hollow cylindrical support tube 94 by conically tapered inner surfaces on a pair of end caps 95 tensioned toward each by a plurallty of bolts 96. The spaces enclosed by the resilient cylin-drical members 92 the flanges 93 and the support tube 94 provide chambers 97 which may be coupled to a source o~
air under greater than atmospheric pressure through an inlet hose 98 and a hose 99 between the chambers 97 to expand the resilient cylindrical members 92 and thereby :
increase their peripheral circumferenceO
A thin, flexible, resilient, spring metal support strip 100 is disposed about and bridges between adjacent ``
25 portions of the resilient cylindrical members 920 The -;
support strip 100 has first and second end portions 101 and 102 respectlvely which are overlapped to provide a variable , ~ '' length outer peripheral surface 103 on which the strip of refractory material 91 is supported. The support strip 96 is retained against axial movement along the cyllndrical ,:
;
-members 92 and its end portions 101 and 102 are guided for relative longitudinal sliding movement by annular ridges 104 molded on the cyllndrical members 92 and flanking the sup- -port strip 100.
The portion of the support strip 100 supportlng :~
the strip of refractory mater'Lal 91 is spaced from the ~ :
cylindrical members 92 to insure that heat ~rom the welding process wlll not damage or rupture the cylindrical mem-bers 92.
The support strip 100 has spring temper biasing its end portions 101 and 102 toward a greater overlapped condition to retain the support strip 100 around the cylindrical members 92 when the cylindrical members 92 contract upon release of air pressure from within the chambers 97c Also to insure such contraction, the device 90 includes two elastic cords 105 tensloned around opposite ends of the support strip 100 between looped ends engaged with pins 106 on the first end portion 101.
The cart-like portion of the device 90 comprises the support tube 94, and two end plates 110 coaxially attached by the bolts 96 to the adjacent flange 93 at opposite ends of the support tube 94. Three wheels 111 are rotatably mounted on each end plate 110 by a mechanism that affords positioning of the wheels 111 at various positions wlth each wheel 111 about equal distance from the axis of the elastic cylindrical members 92 and support strip 96 and aligned for rolling engagement with the inner surface of a pair of tubes tsuch as the tubes 108 shown ln Figures 10 and 11) to coaxially support the device 90 within the tubes and to afford movement of the devlce 90 . . ~
' ~
axially of the tubes. ~ .
The mechanisms mounting the wheels 111 each com-prise a rod 113 mounted for a~ial sliding movement in a . bearing 114 coaxially fixed through one of the end plates .
110. A washer 115 is fixed at the inboard end of the rod 113 and is biased away from the end plate 110 by a coil ` :
spring 116 therebetween. At the other end of the rod 113 `~
is fixed a pivot block 118 on which are pivotably mounted three arms 119 disposed at about 120 degree intervals circumferentially of the pivot block 118, with each of the arms 119 rotatably carrying one of the wheels 111 at its :~
outboard endO A link 120 is pivotably mounted between the center of each of the arms 119 and the housing for the bearing 114 through the end plate 110. The spring 116 blases the pivot block 118 toward the end plate 110 and :
thereby the wheels 111 radially outwardly of the device 90 ~' to an outermost position established by engagement of an ad~usting nut 121 on the rod 113 with the housing of the bearing 114, and the wheels 111 may be moved radially inwardly of the device 90 againsS the bias of the spring 116 to conform the circle defined by the wheels to the inner ;
circumference of a pair of tubes (such as the tubes 108) and afford movement of the wheels 111 over irregularities within the tubes The device 90 is also adapted to grip the inner :~
surface of a pair of butted tubes (such as the tubes 101 shown in Figures 10 and 11), at positions spaced from the strip of refractory material 91 when the strip of refrac~
tory material 91 is in its engage pos~tion so that the strip of refractory material 91 will not move relative to -20- :
', ;' '. .' -the tubes during the welding operation. This is particu-larly advantageous when the tubes are rotated during weldlng.
A portion 122 of each cyllndrical member 92 5 between the adjacent end plate 110 and edge of the support strip 100 is exposed around the periphery of the device 90.
When the cylindrical members 92 are expanded by introducing air under greater than atmospheric pressure into the cham- -bers 97, these exposed portions 122 of the cylindrical 10 members 92 balloon out beyond the periphery of the support strip 100 and engage the inner surfaces of the tubes. Such engagement insures that the device 90 will move with the tubes if the tubes are moved during the welding operation. r The device 90 also includes structure for 15 securing and aligning the consumable backing strip of refractory material 91 in a predetermined position around the support strip 100, and for maintaining such alignment or the backing strip 91 is moved from its retracted to its engage posltions. As is best seen in Figure 12, this 20 structure includes a generally U-shaped clip 123 having a central attaching portion 124 fixed to the support strip 100 adjacent its second end portion 102, and two guide por-tions 125 projecting from opposite edges of the attaching portion 124. The attachlng portion 124 has a row of teeth 127 pro~ecting away from the guide portions 125 and adapted to engage and hold one end of the strip of refrac-tory material 91. Also included are a plurality of cylindrical posts 129 spaced in two rows around the periphery of the support strip 100 with the two rows spaced a~ially of the support strip 100 tc aiford , -, . ~ . . - , , ., ~ 4~
;' ;;.
positioning a portion of the strlp of refractory materlal 91 therebetween after its end is engaged with the teeth 127.
The guide portlons 125 are spaced to receive the free end o~
the strlp of refractory material 91 therebetween over its end attached to the teeth 127 after the portion of the refractory materlal 91 therebetween has been wrapped around the support strip lOOo When the support strip 100 expands to move the strip of refractory material 91 to lts engage position, the free end of the strip of refractory material 10 91 slides over its attached end. During such sllding move- ;
ment, the guide portions 125 guide movement of the free end of the strip of refractory material 91 to insure that lt ~i remains in proper alignment for engagement with the tubes across their butted ends. The guide portions 125 have a spring temper so that they can be resillently compressed by engagement with the inner surfaces of the tubesO The posts 129 have a predetermined length to prevent air pres- ~
sure from within the cylindrical members from compressing -the strlp material more than a predetermined desired amount. -: ,. , :':
~ ~ .
;
.
Claims (7)
1. A device for use during fusion butt-welding between the ends of two tubular members having similar curvilinear inner surfaces, said device comprising a back-ing structure having a contact surface adapted to contact and bridge between the inner surfaces of said tubular members and being adapted for movement from a retracted position with said contact surface spaced from the inner surface of the tubular members to an engage position with said contact surface pressed against the inner surfaces of said tubular members, and a mechanism for moving the back-ing structure from its retracted to its engage position, wherein:
said backing structure comprises:
a thin flexible support strip having over-lapped end portions to provide an arcuate outer peripheral surface;
structure guiding said overlapping end portions for relative longitudinal sliding movement to afford changing the peripheral circumference of said support strip;
a strip of flexible refractory material comprising inorganic particles bound together with a flexible organic binder adapted to have a length dimension which is about the same as that of the inner circumference of the tubular members; and structure for securing and positioning said strip of refractory material on the periphery of said support strip so that the surface of the refractory material opposite said periphery provides said contact surface; and said mechanism for moving the backing structure increases the peripheral circumference of said support strip to press said strip of refractory material into engagement with the inner surfaces of said butted tubular members.
said backing structure comprises:
a thin flexible support strip having over-lapped end portions to provide an arcuate outer peripheral surface;
structure guiding said overlapping end portions for relative longitudinal sliding movement to afford changing the peripheral circumference of said support strip;
a strip of flexible refractory material comprising inorganic particles bound together with a flexible organic binder adapted to have a length dimension which is about the same as that of the inner circumference of the tubular members; and structure for securing and positioning said strip of refractory material on the periphery of said support strip so that the surface of the refractory material opposite said periphery provides said contact surface; and said mechanism for moving the backing structure increases the peripheral circumference of said support strip to press said strip of refractory material into engagement with the inner surfaces of said butted tubular members.
2. A device according to claim 1, wherein said mechanism for moving the backing structure comprises a spring coupled between and biasing said overlapped end portions to increase the peripheral circumference of said support strip.
3. A device according to claim 2, wherein said end portions each have openings adapted to align upon movement of said end portions to predetermined relative positions in opposition to said spring, and said device further comprises:
a trigger pin having an end adapted to releasably engage said aligned openings and retain said end portions in a predetermined position in opposition to said spring, a plurality of locating pins, and sockets on said support strip for removably mounting said locating pins in spaced relationship to pro-ject radially from said support strip through and about centrally between the longitudinal edges of said strip of refractory material.
a trigger pin having an end adapted to releasably engage said aligned openings and retain said end portions in a predetermined position in opposition to said spring, a plurality of locating pins, and sockets on said support strip for removably mounting said locating pins in spaced relationship to pro-ject radially from said support strip through and about centrally between the longitudinal edges of said strip of refractory material.
4. A device according to claim 1, wherein said device includes a cart-like portion adapted for moving axially along the inner surface of said tubular members, and said mechanism for moving the backing structure is mounted on said cart-like portion and is adapted, when in said retracted position, to afford movement of the cart-like portion through the tubular members.
5. A device according to claim 4, wherein said mechanism for moving the backing structure comprises at least one resilient elastic generally cylindrical member mounted at its ends on said cart-like portion and support-ing the surface of said support strip opposite the strip of refractory material on its central portion, and the surface of said cylindrical member opposite said support strip and said cart-like portion define a chamber adapted to receive gluid under greater than atmospheric pressure to stretch said cylindrical member and move said backing structure from said retracted position to said engaged position.
6. A device according to claim 5, wherein said mechanism for moving the backing structure comprises two of said cylindrical members axially spaced on said cart-like portion, with each of said cylindrical members supporting a different end of said support strip and having a portion projecting beyond the edge of said support strip adapted to engage and grip the inner surface of one of the tubular members upon application of fluid under greater than atmo-spheric pressure in said chambers.
7. A device according to claim 5, wherein said cart-like portion further comprises a plurality of wheels at each end of said device a linkage for moving said wheels radially of said cylindrical member between extended and retracted positions and aligning said wheels for rolling engagement with the inner surface of said tubular members to afford movement of said device therein, and a spring for biasing said wheels to their extended positions to center said cylindrical member within the tubular members.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA244,143A CA1044050A (en) | 1976-01-23 | 1976-01-23 | Device for backing butt-welds between tubes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA244,143A CA1044050A (en) | 1976-01-23 | 1976-01-23 | Device for backing butt-welds between tubes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1044050A true CA1044050A (en) | 1978-12-12 |
Family
ID=4105042
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA244,143A Expired CA1044050A (en) | 1976-01-23 | 1976-01-23 | Device for backing butt-welds between tubes |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1044050A (en) |
-
1976
- 1976-01-23 CA CA244,143A patent/CA1044050A/en not_active Expired
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