Abstract:
An internal ring assembly for welding backup against internal hoops of pipes or tanks has a chain assembly of diverse cells. A majority of the cells include a tile of conductive metal for abutting inside walls across a seam of two sections of pipe or tank to be welded, as well as a cell of a roller chain assembly comprising either both a pin-link and roller-link construction or alternatively a pair of mosaic-link constructions. In either case, one of such link constructions is anchored to the tile and the other extends free of the tile for linking with another cell of the chain assembly. In contrast, a minority of the cells are arranged to produce an expansion force on the chain assembly as a whole in order that the chain assembly expansively forces itself tightly against the inside seam of the pipe or tank sections.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
   This application is a divisional of U.S. patent application Ser. No. 10/985,349, filed Nov. 10, 2004 now U.S. Pat. No. 7,410,087, which is a continuation-in-part of U.S. patent application Ser. No. 10/871,554, filed Jun. 17, 2004, abandoned, which claims the benefit of U.S. Provisional Application No. 60/479,549, filed Jun. 18, 2003, all of which disclosures are incorporated herein by this reference. 

   BACKGROUND AND SUMMARY OF THE INVENTION 
   The invention relates to welding backup systems for heat-sink or purge purposes as for application to welding construction of pipelines or tanks and the like. 
   A number of additional features and objects will be apparent in connection with the following discussion of the preferred embodiments and examples with reference to the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the skills of a person having ordinary skill in the art to which the invention pertains. In the drawings, 
       FIG. 1  is a perspective view of a tank in accordance with the prior art; 
       FIG. 2  is a perspective view of a given tile unit in accordance with the invention for chaining together indefinitely with other like tile units, a few dissimilar units aside, and producing an internal ring assembly in accordance with the invention for welding backup; 
       FIG. 3  is an enlarged scale section view taken along line in  FIG. 1 , showing an example operative use environment for such an internal ring assembly in accordance with the invention for welding backup, as for example and without limitation utilization in connection with butt welds of hoop sections; 
       FIG. 4  is an enlarged scale view of DETAIL IV-IV in  FIG. 3 ; 
       FIG. 5  is a perspective view comparable to  FIG. 2  except showing not only given tile units as better shown by  FIG. 2  but also at least one embodiment of dissimilar tile units in accordance with the invention; 
       FIG. 6  is an enlarged scale section view taken along line IV-IV in  FIG. 3 ; 
       FIG. 7  is an enlarged scale perspective view, partly broken away, of the jamming or wedging tile unit in accordance with the invention and as previously shown in  FIGS. 3 and 4 ; 
       FIG. 8  is an elevational view of an active length of tile units in accordance with the invention for constructing an alternate embodiment of an internal ring backup assembly in accordance with the invention, wherein some portions are broken away to foreshorten the section and others are removed from view; 
       FIG. 9  is a top plan view thereof; 
       FIG. 10  is an elevational view of an alternative embodiment of an actuator for the  FIGS. 8 and 9  embodiment, and which actuator provides a user with a mechanical advantage for foreshortening the active length of tiles therein; 
       FIG. 11  is a perspective view of a further embodiment of linked together tiles in accordance with the invention; 
       FIG. 12  is an elevational view of the embodiment of  FIG. 11 ; 
       FIG. 13  is a reduced scale top plan view, the tank wall being shown in section, showing an example operative use environment for the linked together tile units in accordance with the embodiment of  FIGS. 11 and 12  in combination with an active length of tile units comparable to the embodiment of  FIGS. 8 and 9 , partly broken away; 
       FIG. 14  is an enlarged scale top plan view comparable to  FIG. 13  except showing a further embodiment of an actuator in accordance with invention for foreshortening the active length of tile units; 
       FIG. 15  is an enlarged scale section view taken along line XV-XV in  FIG. 1 , except including illustration of an additional embodiment in accordance with the invention for welding backup, as more particularly for the weldment joining a nozzle to the domed cap of the tank; 
       FIG. 16  is an enlarged scale perspective view of the annulus backup plate in  FIG. 15 ; 
       FIG. 17  is an enlarged scale section view showing another embodiment in accordance with the invention for welding backup, as more particularly showing a purge arrangement for creases; 
       FIG. 18  is an enlarged scaled elevational view of the ventilated tube and its sheath in  FIG. 17 ; 
       FIG. 19  is a perspective view of the spaced end portions of a belt for pipe welding backup in accordance with the invention, wherein middle portions are broken away to foreshorten the illustration; 
       FIG. 20  is a reduced scale perspective view showing one end of the belt of  FIG. 19  lapped externally over the outboard course of a hoop seam for the tank of  FIG. 1 ; and 
       FIG. 21  is an enlarged scale sectional view of the tank, with portions broken away, including illustration of portions of the belt  FIGS. 19 and 20 , as well as a clamp and come-along device in accordance with the invention for cinching tight and clamping the belt in a use position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows a tank T in accordance with the prior art. Briefly, the tank T has a domed top-end or cap E outfitted with various access fixtures or nozzles N. This type of tank is conventional in process industries for the production of pharmaceutical products, whether that be end-products or, more typically, intermediate products. The prior art prefers such tanks to be welded up out of stainless steel components. The prior art also prefers stainless steel weldments to be backed up by heat sinks as well as purged of oxidizing gases to the extent practical. The longstanding problem has been, naturally, to what extent is practical under the circumstances. 
     FIG. 2  shows a given tile unit  20  in accordance with the invention for chaining together indefinitely with other like tile units, a few dissimilar units aside. As more particularly shown by  FIG. 3 , a chain of like tile units  20  allows production of an internal ring assembly  10  in accordance with the invention for welding backup. In  FIG. 2 , the given tile unit  20  comprises a tile  21  mated to a discrete cell of a roller chain, including pins  22 , bushings  23 , rollers  24 , roller-link plates  25 , and pin-link plates  26 .  FIG. 6  better shows that between either the roller-link plates  25  or the pin-link plates  26 , preferably at least one of such plate pairs  25  or  26  are fixed to a mounting fixture (eg., base plate)  27  for fastening tight to the tile  21 . 
     FIG. 3  shows an example operative use environment for such the internal ring assembly  10  in accordance with the invention. For example and without limitation, the tank T might have a six foot ( ˜ 1.8 m) outside diameter, and even if the top end cap E is welded in place, it will include a manhole for worker access in and out of the tank. In use, a worker constructs a chain assembly  10  of the target inside circumference for a match as close as possible. Then the worker temporarily hangs the chain assembly  10  on the inside wall of the tank T at a seam for butt welding. One way to do this is by progressively working around in a circle and taping the chain assembly  10  to the tank T&#39;s wall at angularly spaced locations by vertically-arranged strips of aluminum tape or the like. The aluminum tape just provides temporary holding power. Regardless if it takes one, two or more workers to hang the chain assembly  10 , this step of the workflow is readily aided by the tape (whether it be simply duct tape) temporarily holding the chain assembly  10  at its elevation in the tank T on the seam. 
     FIG. 4  shows better what is encircled by detail IV-IV in  FIG. 3 . Plural (eg., three in this view) tile units (eg.,  30 ,  40 ,  50 ) differ from the given tile units  20  as follows, wherein preferably the given tile units  20  proceed uninterrupted by any other dissimilar tile units until meeting at the opposite ends of the circle (or hoop of whatever geometry). The lever unit  30  has a handle-lever  32  for causing a jamming or wedging action among tile units  30 ,  40 ,  50  in order to apply an expansion force on the chain assembly  10  as a whole comprising substantially a chain of the given tile units  20 . As shown better by  FIG. 7 , the lever tile unit  30  has its lever pivoting on chosen pin  22 , the lever has a tool end forming dual forks  34  for engaging the pin ends of succeeding tile unit  40  as well as has a concave, spring-biased pressure applicator  36  for engaging the rounded lobes of the dual roller-link plates  25  of succeeding tile unit  40 . 
   Returning to  FIG. 4 , tile unit  40  proceeds to terminate in dual forks  44  for engaging the pin ends  22  of mosaic link plates  46 , which in turn proceed to terminate in forks  48  for engaging the pin ends  22  of the next successive tile plate  50 , which has like mosaic link plates  56  having fork ends  58  for engaging the pin ends  22  of the first-in-line given tile unit  20 . Mosaic link plates  46  and  56  are characterized as having roller-gripping origins and flaring out to (or otherwise changing into) pin-gripping terminations. As can be reckoned by  FIGS. 3 and 4 , operating the lever  32  counterclockwise causes the tiles of tile units  30 ,  40  and perhaps  50  to lift away from flush contact with the wall of the tank T, and thereby release or break the application of an expansion force. In  FIG. 3 , the lever  32  is depicted by solid lines to show the lock or jamming position, and is depicted in dashed lines to show the release or break position. In reverse, operation of the lever  32  to the jamming or wedging position shown by  FIG. 4  achieves the requisite jamming or wedging force on the chain assembly  10  as a whole to expand it snugly in good thermal contact with the wall of the tank T. 
     FIG. 5  shows not only given tile units  20  as better shown by  FIG. 2  but also at least one embodiment of dissimilar tile units  60  in accordance with the invention. These dissimilar tile units  60  have smaller tile-footprints than other tile units in order to allow assembly of a chain  10  made of fractionally smaller units. This provides modularity when it comes to building a chain  10  of a selected length. Adding or subtracting the small tiles  60  provides finer granularity in achieving the desired length nearly exactly. Put differently, this allows allow formation of a chain hoop  10  of fairly precise measure. The chain hoop  10 &#39;s final measure is not limited to integer multipliers of the standard tile footprint of tile units  20 . These tile units  20  might measure four to six inches ( ˜ 10 to 15 cm) in span. In contrast, the dissimilar tile units  60  are about half the size of the other tile units (eg., two to three inches, or  ˜ 5 to 7½ cm, in span). The dissimilar tile units  60  also feature mosaic-style link plates  66  having fork ends  68  as described more particularly above. 
   To return back briefly to  FIG. 3 , among other things, it shows the internal ring  10  expansively forced tight against the tank T&#39;s inside wall. Moreover,  FIG. 3  shows that adjacent tiles  21  are scalloped alternately concave and convex to abut one another more compactly. This provides several advantages. The tiles  21  adapt better to use on tanks having a wide range of inside diameters. That way, an internal ring  10  can be formed of larger or smaller overall diameters with the tiles  21  still compactly mating each other because each relatively pivots at its edges relative its neighbors. Also, the mating concave-convex edges narrow the gap between adjacent tiles  21 , which provide better thermal coverage over the whole circumference of the seam. 
     FIGS. 8 and 9  show an alternative strategy for achieving the application of the jamming or wedging force preferred for the invention. That is,  FIGS. 8 and 9  show an “active” length  70  of tile units in accordance with the invention for constructing an alternate embodiment of an internal ring backup assembly in accordance with the invention (compare, eg., internal ring backup assembly  270  in  FIG. 13 ). To turn briefly to  FIG. 13 , it shows an internal ring backup assembly  270  comprised of an active length  70  and, in contrast, a “passive” length  200 . The “passive” length  200  forms the greater fraction of the overall length of the internal ring  270 &#39;s circumference. In contrast, the “active” length  70  forms only a minor fraction thereof. The “active” length  70  functions like a coil compression spring, which acts against the two ends of the “passive” length  200 . The “passive” length  200 , as is true with chains of tile units  20 , has practically no compressibility. Hence whatever compressive force is applied to the ring  270  as a whole by the “active” length  70  is of course carried and held by the “passive” length  200  as well. 
   To turn back to  FIGS. 8 and 9 , the active length  70  is serviced by an optional embodiment of a jamming or wedging force applicator  72  in accordance with the invention. The active length  70  is produced from a series of tile units  74  the bottom out in tiles  71 . Tiles  71 , as well as tiles  21 , are preferably produced of a high conductivity metal, such as copper, and more preferably of high-conductivity oxygen-free copper. The remainder of the construction materials may comprise any various materials including steel, aluminum, stainless steel, spring steel (ie., for springs), steel cable and so on. 
   In the active length  70 , the tiles  71  are held together by a tether. In  FIGS. 8 and 9 , one embodiment of a tether includes for example and without limitation a looped steel cable  75 . The cable  75  passes relatively freely through apertured mounting blocks  76 , and adjacent tile units  74  are biased apart by compression springs  77 . A T-headed actuator  78  operates to allow a worker to manually acuate the actuator  72  (which is in the “up” direction in  FIG. 8 ) to shorten the length of the active length  70 . That way, a worker can insert the foreshortened active length  70  between the ends of a passive length (eg.,  200  in  FIG. 13 ). Once inserted, the worker can relax his or her squeeze on the actuator  72  and thereby obtain an expansion force on the chain assembly  270  as whole. The expansion force naturally forces the tiles  71  and  220  against an inside wall of a hoop section (see  FIG. 13 ). 
     FIG. 10  shows an alternative embodiment of an actuator  172  for the  FIGS. 8 and 9  embodiment of an active length  70  of tile units. This actuator  172  provides a user with a mechanical advantage for foreshortening the active length  70 . The actuator  172  comprises a standard  174 , a trigger-actuated traveler  176 , and a pair of pull rods  178  (near side only in view) secured to the traveler  176  and flanking the standard  174 . Each pull rod  178  terminates in a lugged-end formed with lugs over which the centers of the cables  75  are looped. A user operates this actuator  172  as follows. Squeezing the trigger of the trigger-actuated traveler  176  causes a mechanism (not shown) inside the traveler  176  comprising a ratchet and drive gear (again, not shown) to drive the traveler  176  up the standard  174  (eg., “up” given the orientation of  FIG. 10 ). The effect this has on the pull rods  178  is to exert a pulling force on the cables  75 , causing the cable centers to pull out as indicated by direction arrow  180 , which in consequence foreshortens the active length  70 . 
   The traveler  176 &#39;s internal ratchet mechanism locks the travel of the traveler  176  on the standard  174  after each squeeze of the trigger. The user can therefore squeeze the trigger several times in a row and successively tighten the foreshortening of the active length  70  until all the slack is squeezed out between adjacent tiles  71 . Since the ratchet locks the foreshortening of the active length  70  after each squeeze of the trigger of actuator  172 , the active length  70  remains compressed in its compact-most state until the ratchet is let off. That way, a user can leisurely squeeze down the active length  70  in one place and then carry it over to another place where it inserts between the ends of a passive length  200 . The worker can therefore do the following. The worker might squeeze out the slack in the active length  70  by doing so with the tiles  71  laying flat on the floor. Then, with the active length  70  locked down by the traveler  174 , the user lifts the active length  70  up off the floor and places it in its use position against the tank T&#39;s wall. The locked down active length  70  is released from being locked down by the ratchet, and spread apart, by the user releasing the traveler  176  on the standard  174  as including by a release button  182 . 
     FIGS. 11 and 12  show better the “passive” length  200  of linked together tiles  220  in accordance with the invention. The passive length  200  comprises tiles  220  linked together by a flexible band  250  of woven copper filaments. The band  250  is indeed flexible but little else. It affords only minimal stretch or foreshortening, and is considered not resilient for application of a compressive force. The band  250  fairly much has a fixed length, plus or minus a small fractional percentage of stretch or compaction due to the weave. Each tile  220  is shown allowing up to four (4) rivet connections  228  to the overlying flexible band  250 . The overall length  200  of tiles  220  linked together this way is termed a “passive” length for convenience sake in this description, but also in recognition that, in contrast to an “active” length  70 , each tile  220  is situated fairly tightly-abutted next to its neighbors. Consequently, passive lengths  200  do not contribute to the jamming or wedging action as does a compressively-biased active length  70 . Additionally, the “overall length” of a passive length  200  might be produced as an assembly of sub-assemblies, each sub-assembly comprising a dozen or dozens of discrete tiles  220  or so. 
     FIG. 13  shows the passive length  200  deployed in combination with the active length  70  in order to obtain internal ring assembly  270  for welding backup. The passive length  200  forms the greater fraction of the overall length of the internal ring assembly  270 &#39;s circumference. In contrast, the active length  70  is only a minor fraction thereof. During set-up, a worker would tape up the passive length  200  in place separately. What that accomplishes is the passive length  200  being temporarily stabilized in place over the seam except for a gap of twelve to twenty inches or so ( ˜ 30 to 50 cm). The gap is naturally defined between the opposite ends of the passive length  200 . It is this gap which is to be filled by the active length  70 . 
   The factors which determine the selected “length” of the active length  70  includes the following. One factor is the linear measure of the active length  70  in its relaxed state, ie., whether it measures considerably longer than the gap it has to fill. Another factor is contrasting factor. That is, the linear measure of the active length  70  in its compact-most state because of course it has to insert within the gap. That way, when the compression is released, the active length  70  spreads apart and forcibly provides the wedging or jamming action for the overall internal ring  270 . When this is done, all the tiles  71  and  220  alike are forced into good thermal contact with the tank T&#39;s inside wall. 
     FIG. 14  shows a further embodiment of an actuator  272  in accordance with invention for foreshortening an active length  70  of tile units  71 . This actuator  272  comprises a bar  274  carrying a stationary bracket  275  on one end. The stationary bracket  275  has a pair of hooks  278  for hooking on the lugs of an end mounting block  76 . The bar  274  further carries a trigger-actuated traveler  276  which also has a pair of hooks  278  for hooking on the lugs of the opposite end&#39;s mounting block  76 . 
   A user operates this actuator  272  as follows. Squeezing the trigger of the trigger-actuated traveler  276  causes a mechanism (not shown) inside the traveler  276  comprising a ratchet and drive gear (not shown) to drive the traveler  276  inwards on the bar  274  (eg., “left” given the orientation of  FIG. 10 ). The effect this has on active length  70  is to foreshorten it. As described more particularly above, the user can shorten the active length  70  in a series of squeezes because of the locking action of the ratchet, and do so on the floor until ready to place in the gap. Once inserted in the gap, the foreshortened active length  70  is allowed to spread apart again by the user releasing the traveler  276  on the bar  274  as including by the release button  282 . 
     FIG. 15  shows a welding backup arrangement  80  in accordance with the invention for the weldment that joins a nozzle N to the domed cap E of the tank T. This welding backup arrangement  80  comprises an annulus backup plate  82 , a stemmed lid  84  that includes a stem portion  86 , an actuator  87 , and a purge fitting  88  for supply of a purge gas. It is an aspect of the invention that the welding backup arrangement  80  operates to clamp annulus backup plate  82  by virtue of the lid  84  and actuator  87  opposite the weld seam for at least purge purposes, and perhaps light-duty heat-sink purposes. The lid  84  operates not only as a heat sink but the stem portion  86  is sized for closely fitting inside the top end of the nozzle N and thereby assist in maintaining the roundness of the nozzle N&#39;s top end during the welding operation. That way, this helps prevent the nozzle N&#39;s top end from distorting into an ovoid shape or the like. 
   As  FIG. 16  shows better, preferably the annulus backup plate  82  is slotted as shown to allow flexure and conformance to complexly-warped geometries of a domed structure. Preferably the annulus backup plate  82  is produced of a high conductivity metal such as copper, and more preferably of high-conductivity, oxygen-free copper. 
     FIGS. 17 and 18  show another embodiment in accordance with the invention, as for more particularly achieving a purge arrangement  90  for both creases (as shown) and cylindrical seams (not shown) or the like. In  FIG. 17 , this crease may be typical of—and only as an example and without limitation—being formed between a nozzle N and end cap E. The crease can be serviced by purge arrangement  90  which comprises a seal of metallic tape  91  (aluminum is suitable) having an adhesive layer  92  for sealing in a ventilated tube  93  and its porous sheath  94 . Preferably the ventilated tube  93  is formed of copper as well, and is perforated regularly with vents  95 . Preferably the sheath comprises a woven copper-filament flexible conduit. In use, the ventilated tube  93  is preferably serviced by a metered gas source  96 . 
   This purge arrangement  90  can be comparable adapted for other uses than besides with creases alone. That is, purge arrangement  90  can be satisfactorily strung around an inside diameter or an outside diameter to provide purge service welding a seam from the opposite side of the tank wall as the purge arrangement  90 . 
     FIG. 19  shows at least the spaced end portions of a belt  100  for pipe welding backup in accordance with the invention, as for lapping externally over the outboard course of a hoop seam for the tank T (see, eg,  FIG. 20 ). Preferably the belt  100  of  FIGS. 19 through 21  comprises a copper braided construction. One end  102  is formed as a mated, hard-metal loop end such as of brass, bronze, beryllium or like metals amenable to a brazing, soldering or fusion mating. The terminating end  104  can be simply a cut-off end as shown in either of  FIG. 19  or  20 . 
     FIG. 21  shows a minor section of the tank T with the belt  100  girdling it in order to better show a clamp  106  and come-along device  110  in accordance with the invention. The come-along device  110  has a lever actuator  112  which when actuated in the clockwise direction (as reckoned by  FIG. 21 ) causes its pin connection  114  with the belt  100 &#39;s loop end  102  to be forced apart from a clamped connection  116  with a marginal end-portion  104 &#39; of the belt  100 &#39;s blank end  104 . To fully tighten the belt  100 , operation of the lever actuator  112  preferably takes several strokes. Preparatory to each spreading stroke, the come-along  110 &#39;s clamp  114  is tightened and the belt  100 &#39;s clamp  106  is relaxed. A stroke of the come-along  110  cinches the belt  100  incrementally, which slips through the belt  100 &#39;s relaxed clamp  106 , which at the end of the stroke is tightened. The come-along  110 &#39;s clamp  114  is released, manually slid along the belt  100  in the direction of the loop end  102 , during while the lever  112  is being pivoted fully counterclockwise, then clamp  114  is re-tightened. Belt-clamp  106  is next relaxed so that a successive stroke of the lever  112  further tightens the girdle force of the belt on the tank T. Once the desired girdle compression for belt  100  is achieved, the come-along device  110  may be removed and a worker is then preferably afforded an inventive opportunity to weld and inside weldment to the seam of the tank T with the heat-sink service of cinched-tight belt  100  on the outboard side of the seam. 
   The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned, and accordingly reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.