CA1093866A - Heat sink welding and purging apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A heat sink welding and purging apparatus for use in the welding of pipe joints for piping to be used with nuclear power systems and the like wherein the weld area must be kept below a temperature at which the dangers of carbide precipitation occur. The various embodiments include expandable heat sink and sealing bladders which are expanded in use to respectively seal the adjacent interiors of the ends of the two pipes to be welded at the adjacent joints. After expanding and sealing the pipe openings, coolant is fed into the interior of the apparatus to cool the joint being welded. Also purging gases may be used to eliminate undesirable atmospheric gases adjacent the weld joint.

Description

This l~ventio~ rela~es generally to apparatus for use with the weld-ing oE piping ~o be used in nuclear po~er plants ~nd systems. I~ relates specifirally ~o ~he apparatus used for heat sinking and purging o the piping.
A co~mon problem ~ith knowm devices used in the welding of pipes is that they do not of~er ~he flexibility of both coollng as a heat sink together with purging features. Known type devices merely provide heat sink or cooling functions, or purging Eunctions, but not the ~ombination of same.
Another problem with knvwn type devices are that they are not readily adaptable or large scale operatlons or ~ass welding of numerous piping. Tha~
is, they are so complex and involved that much ~ime is spent in setting them up ~nd they are not easily transferable from one set of pipes to be welded to another set.
Another problem with known ~ype devices is that they are not readily adaptable for use with either ~as type purging functionæ and/or liquid-type purging and cooling functions.
~ nown prlor art U.S. patents which may be pertinent to this invention are as follows:

2,470,744 May 17~ 1949 2,819,517 Jan. 14, 1958

3,19~1,466 July 13, 1965 3,431,945 ~ Narch 11, 1969 3,779,068 `~ Dec. 18, 1973 3,902,528 Sept. 2~ 1975 None o these known prior art devices offers the new and unique features of the invention disclosed herein.
An object o the presen~ invention is to pro~ide a combination heat sink and purging apparatus for use with pipe ~oint welding of piping to be used with nuclear systems.
Another ob~ect of the prasent invention is to provlde apparatus which ofers the fle~ibility of either purging an area adjacen~ a join~ between two pipes ~o be welded as well as providing heat sink or cooling funotions ~o said area.
A further objec~ oE this invention is to provide apparatus whioh will : ., be easily and quickly installable in the re~pective open ends o pipes to be joined by appropriate welding. It is importa~t that said weld~ in the case of piping to be used with nuclear sys~ems, be held below a given te~perature l~
order to prevent the dangers of carbide presipitation. This is effeeted by the apparat~s of this invention through the heat sink and coolîng func~ion thereof.
A s~ill Further object o~ this in~ention i~s to provide ~xpa~dable bladder structure which will seal the ad~acent e~ds of piping to be joined and welded, and also will permit the addition of either cooling fluid therethrough for heat sink purposes as well as 1uid for purging purposes.
Ths various embodiments disclosed herein o thi~ invention teach a number of ways of sealing the open ends of piping which are to be jo:inted together by appropriate welding. The embodiments all have the common feature of sealing the internal ends oE said pipin~ and all also have the Eeature of permitting cooling fluid to be orced in and allowed nut of said apparatus. In addition structure is provided for applying purging g2S or fluid to the area adjacent the jo mt being welded for displacing any undesired alr or other gas therefrom. Also, after the initial root weld i9 made, coolan~ may be fed into the joint area for additional cooling thereof.
2Q The devlce of this invention ha9 thesdvantage of being usable as a purgi~g unit, a heat sinlc unit, or combina~ion of the two. ~hen using the devices of the purge unit, inert gas or air is used to inflae2 the bladder structure~ Bleed means associated with the bladder struc~ure permit the in-flated bladders to be defla~ed ~n order to ~acilltate their removal from the pipe after the welding of the pipe joint.
When ths apparatus i6 being used for hea~ si~ing and purging in co~bination, there are many factors to be considered such as: the pipe schedule, ~he different coniiguration of the pipes, the weld deposit, and the heat sink ~emperature desired. Because of these factors, the cooling liqu~d may vary fro~
chilled water to water-glycol mix to cryogenics such as freon or LN2.
~ ormally, ~he apparatus ok this invention will be used with pumping units ofering full ilow capability and appropriate ~ontrols therefor which are .

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capable of variable pressure ranges. One embodiment of the device shows the use of pre-shaped coils or blocks which are expanded into engagement with the pipe interiors by means of the expandable bladder units. When a cryogenic coolant is being used a high quality insulating pad normally will be placed be~tween these coils or blocks and the bladder, in order to absorb some of the initial cold shock to the bladders.
Another feature of this invention is that all of the gas and liquid lines are equipped with quick disconnect fittings in order to simplify the quick transfer of the pumping and purging apparatus from one apparatus and pipe set-up to another. This permits the quick and rapid welding of pipe joints on an assembly line or mass production type basis. This is very important for usable application on a commercial basis.
Another very important feature Ls in the fact that w:Lth this combi-nation apparatus the use of purging gas therewith will have no effect upon the cooling and heat sinking process, that is, the proper cooling of the weld and adjacent area will take place irrespective of whether or not the system is purged by use of a purging gas. Also, if additional cooling of the weld area is desired, t~e use of purge gas may be completely omitted and additional cool-ant substituted therefor.
The range of cooling for this apparatus and for the nuclear piping to be joined by welding is in the minus 50 degree F. range and the expandable bladders of this apparatus are made of silicone rubber which has the character-istics and capabilities of operating very satisfactorily within this temperature range.
The present invention is broadly defined as an apparatus for .
heat sinking and purging pipes to be welded for use in nuclear systems and the like, comprising: first means for sealing internally the adjacent ends of two abutting pipes to be welded, second means for directing a coolant into the first means for cooling the sealed abutting pipe ends in order to effect a heat sink function in order to keep the temperature of the weld area below that where the dangers of carbide precipitation occur, the first means rw.

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including inflatable members mountable internally of each of the pipe ends and expandable by the coolant in order to form a tight seal internally therewith and the second means including coolant feed lines and coolant return lines associated with the inflatable members in order to cool the pipe ends adjacent the joint to be welded, and third means for purging the atmosphere in the sealed pipe ends between the inflatable members internally of the joint being welded.
Figure 1 is a perspective view of the basic system for use with the various embodiments of this invention.
Figure 2 is a side elevational view, partly in cross section, of the first embodiment of this invention.
Figure 3 is an end view, partly in cross sec-tion, taken generally along line 3--3 of Figure 2.
Figure 4 is a side elevational view, partly in cross section, of a second embodiment of this invention.
Figure 5 is a perspective view of a third embodiment of this inven-r~/

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tion.
Figure 6 is ~ side elevational view, partly in cross sectlon, o~ thethird embodimen~.
Figu~e 7 is an end view, partly in cross sec~ion, taken generally along line 7~7 of Figura 6.
Figure 8 is a side elevational view, partly in CrOQS section, vf a fourth embodiment of this invention.
Figure 9 is an end viewl partly in cros~ se~tion, taken generally along line 9--9 of Figure 8.
Figure 10 is an end view, par~ly in cros~ sec~ion, taken generally along line 10--10 of Figure 8.
Figurè 1 of the drawings, indicates by refer2nce numeral 10, the basic heat sink and purging app~ratus of chis invention as installed at th~ ~oining point 20 o~ the two ends of pipe 12 for ~he purpose o~ welding same. Le~ter A
indicates the basic apparatus and the gas and liquid lines are shown as extend-ing to the left of the purging apparatus ~hrough the exit pipe 12. The line 14 is for the input of coolant Prom an appropriate coolant compressor AS shown, connected by a coolan~ line thereof 14' and a quick connec~/disconnect coupling 16. Similarly, a coolant re~urn line 15 is provided which is connected to the coolant compressor by return line 15' and another quiok ~onnec~or 16. A purg-ing ~a9 unit is slso shown connected to purgi~g line 18 through quick connect/
disconnect member 16 and purge line 18'. Quiclc connect-disconnect fittings 16 are provided at the ends of lines 14', 15' and 18' 80 that ~he cooling com-pressor unit ~nd the purge gas unit ~ay be used with a large nu~ber oP heat sink and purge apparatus for a series of pipe join~s to be welded. Thus sav-ing the cost of multiple compressor and gas units, and also gr~atl~ increasing the efficiency and mass production cap~bilities of the overall combination.
Looking at Figures 2 and 3 which show a ir~t embodlment of thls invent~on, the app~ratus will now be described in de~ail. Main tubular support me~bers 22 are provided which flre mounted in ~he cen~ral interlor o~ the pipes 12 and straddling the ~oint to be welded with disc support me~bers 26 h~ving clamping brackets 28 with line eng~ging portions 27 provided thereon. Appro-priate conventional nut3 a~d bol~s 29 are used to secure the clamps to the bracket me~bers. A circumferential ring 32 i8 appropriately f3stened to the bracke~ member 26 and provided with a resilient ~ounting hub 34~ The purpose of these bracket ~embers are to support and retain the input and output coolant lines and the purging line. As described above, the input coolant line 14 which in the drawings is from the left connects to an input T 24 whlch is a tee coupling. The input linP then connects with feed ~hrough coupling 21 in each of the support braekets and then connects wi~h an ell angle input eed 24' o~ the far right of the Fig~re. Resilien~, expcmdable bladder members 30 of silicone rubber or the like are provided about the outer circu~ference of ~he main tubular members 22. ~hen the input coolant is applied to input line 14 and through the T member 24 and L coupling 24' to the i~terior of said bladders, the coolant which is under pressure will expand the bladders 30 Into firm, positive engagement with the inner portion of the respective pipes 12.
Thus expanded, these bladders will form airtight seals between the ~oint to be welded and the rest of the interior of the pipe. Also, the coolant will ~unc-tion as a heat sink to absorb the excess heat from ~he weld as it i5 being made.
The raturn coolant arrangement is sho~n along ~he bo~om poreion of Figure 2 and consi~ts of the return coolant line 15 9 connected to an appropri-ate tee member 25 and an L member 25' through the feed through coupllng me~bers 23 in the supports 26. With ~his arrangement of coolant input and output, a conti~uous flow of ~oolant may be provided which also may be varied as to rate in order to determine and control the amount of heat sink effect at the ends of pipes 12 and the joint therebetween 20. In some cases, after a root paRs is made at ~he weld ~oint, that i8, the first ini~ial welding step which seals the contact be~ween the pipe ends so that the joint then becomes aix and g~s tight, coolant may be introduced into the area between ~he bladders 30 and the joint.
This will provide additional direc~ cooling of the joint.
Ho~ever, in most c~ses a purging gas will be added to this area by means of the purging lnput line 13 which connects to a coupling 3S on the left support 26 and in turn is exhausted by another coupling 36 in order to add and exhaust purge ga~ such as Argon into said interior. It generally is not neces-sary to ha~e a return line ~or the purging gas because its primary effect i8 ~o purge or dlsplace any air or combus~ible fluid within the interior area B

3~
, while the welding is being done. Obviously, ~hen the heat s~nk bladders 30 are collapsedg the purging gas will be co~pletely exhausted.
Looking now at Figure 4 of the drawings, the sec~nd embodiment of this invention will be described. This may basically be similar ~o that described for the internal stru~ture within m~mbers 22 of the first e~bodiment.
This second embod1ment basically consists of two sol~d di~cs 46 havlng mounted about the outer clrcumfe~ence thereof infla~able bladders 40 w~ich when in-1a~ed con~act with the internal circu~ference of the pipes 12 along contact area 42. Again, input coolant lines are indicated at 14" fePding to input couplings 44 and 44' in the re3pective heat si~k a~d bladder members 40 wlth the left disc 46 being pro~ided with an approprlate feed through 41 for the llne 14 "' which connects to the input 44". Coolant return lines are lndi-cated by 15" whlch are also appropriately connec~ed to an outlet coupling 45, and a feed through 43, llne 15"' a~d another outlet coupli~lg 45'. R purge input is indicated at 18 which connects to a eentral feed throu~h member 47 fvr the purpose of applying purge gas to ~he interior C as i~dicated. As can be seen, a right side ~eed through member 47' is provided for e~hausti~lg the purge gas.
In the operation of this second embodimen~, the ~wo infla~able heat ~0 sink and bl~dder units will be appropriately inserted into the ends of pipes 12, close to ~he join~ 20 to be welded, and ~hen the coolant couplings will be coupled to the coolant compressor and the bladder~ inflated to form an air-tight seal withln the pipe ends. The rate of coolant flow may be ad~usted for the desired amount and rate o~ heat sink effect. Purging gas may then be ~dded or, as mentioned above, additional coolant through ~he input line 18 may be added af~er the first weld pass is made.
Flgures S, 6 and 7 show a third embodiment of this ln~entlon. This apparatus co~pri~es two inflatable bladder me~bers 50 of silicone rubbPr or the like, mounted a~d supportad by tubes 51 and 51', which ar~ iQ turn sup-ported from a central pipe 57 by means of ~low through spa~er elements 53.The spacer eleme~ts 53 will permit fluid ~o pass between the outer circumferY
ence of the pipe 57 and the inner diameter of tha tube~ 51 and 51', as will be described i~ detail below. A plurallty of support plates 52 are also pro-~1~.?~
.~

vided having cen~ral ap~rtures therein which closely it over the tubularmembers 51 and Sl'. Comple~e~tary and sligh~ly larger di~cs 521 are provided within the bladder members per se. These may be best seen in Figure 6. Ap-propriate bol~3 54 and nuts 56 secure the plates t~ the walls of the bladders 50. The plate 52", on tbe far right of the Flgure 6 view, is slightly dif-ferent from ~he other plates in that no central ~perture is provided therein.
As can be seen in Figure 69 appropriate welding 55 secures the inner plates 52' to the respective tubular members 51 and 51'. .~i5 i8 for the purpose o providing mechanical suppor~ ~0 the bladder structures as w211 as to achie~e the 1uid tlght integrity thereof.
A coolant input line 14 i.s connected to the screw threaded end of input pipe 57 for applying ~he coolant ~hrough the center oi pipe 57 to the bladder on the right. W~lile in the previous embodiments, the coolan~ has been set orth as being any desired type such ~8 water, ireon, or other type re-frigerants etc. In this embodiment, the coolant would normally be water be cause no return line is provided to the coolant pump, and the coolant is simply exhausted or wasted on ~he surrounding ground area. After the rightmo~ blad-der S0 i~ lnflated by the coolant under pressure, the overflow will pass through the ~ubular member Sl' between the bladders 50 and then i~to the left-mos~ bladder to inflat same. The overflow fro~ this bladder, a~ter e~pansion of same, will be through ~he tubular member 51 tG waste exhaust as ~lresdy men~ioned. Again, ~he coolant flowing through both bladders wlll f~mctlon as a heat sink for the ends of the pipes 12 and weld joint 20.
Ater the blad~ers have been inflated purgi~g gas ~ay aiso be applied by mesns of the purge lines lô and 18' connected ~o the feed ~hrough members 60 provided in the support plates 52 and 52' of ~he le~tmost b~adder. These feed throuSh members 60 are approprlately scraw threaded on the ou~slde cir-cumference thereof for engagement with center tapped apertures 63 provided in the plates 52' and secured on the outside of plates 52 by means of locking nuts 30 61. Connecting lines 68 and 68' are provided withln the bladder to connect ~he respective feed through members. Thus, as can readily be visualized, when input purging fluid is applied through line 18 ~o ~he feed thsough coupling 609 the appropriate fluid will be ronveyed into the interior be~ween the bladders and the inside portion of the pipe joint 20. An 'ner~ gas such as Argon may be applied thro~gh the in~u~ line 18 or as already mentioned coolan~ may also be ~ed therethrough. The lower input 18 feeds the purging gas or coolant into the device while the upper line 18' is used to exhaust same.
The fourth embodlment shown in Figures 8, 9 and 10 will now be described. This embodiment basically comprises u~its 70 and 70' which are actually q~ite similar in construc~ion. Mounted at one end o~ each o these uni~s, as shown in Figure 8, are inflatable bladder membe.rs 30' similar to that already discussed with the embodiment o~ Figure 2. These bladders 30' are connected by an infl~tion input line 72 to a T connection 82, and by continu-ing infl~tion line 72' to the L member 82'. Exhaust or de1ation line 73 is provided which is appropria~ely connected to the T member 83 and further by means of de~lation or exhaust line 73' to the L 83'. The infln~ion and de-flation procedure i8 like that already described above. While normally tllese bladders would be inflated merely for positioning and blocking purposes, coolflnt could also be used as the infla~ion means and to provide additional cooling to the pipe structure.
Spaced along the members 70 and 70' ~nd toward the other ends of said me~bers from the bladders 30' are smaller inflatable sealing and cooling blad-ders 40'. ~hese bladders are somewha~ similar to ~he bladders 40 describedin the embodiment of Flgure 4. However, unted upon the outer surface cir-cumferentially there~f are metal coolant coils 76 which are for the purpose of cooling and heat sinking the pipe ends at e~tre~ely low temperatures by cryo-ge~ic cooling. Cryogenic cooling functions at extremely low temperatures and the cooling coil 76 and approprlate feed and exhaust lines therefor must be resistant to ehis extremely low temperature and be both extremely strong and fle~ible at low temperatures. The inpu~ coolan~ line is shown at the lef~ o~
Fig~re 8 as 74 feeding to the ~luid coil 76 of the me~ber 70. A~ exhaust for this coolan~ is irldicated by reference nume~al 75. The coolant input for the right member 70' is indlcated by line 74' while the exhaust therefor is indi-cated by the line 75'. Of cour6e the cryogenlc cooling is fed hy appropriaee extremely low temperature pumps, e~c., no~ shown, similar, however, ~o ~he coolant co~pressor shown in Figure l. The ~nput line for the inflating/

coolan~ of the bladder 40' is indicated by reference n~meral 94 connecting ~o a T 92 and th~n connected by further line 941 to ~he L 92', and ~he exhaus~ for the inflation~coolan~ of ~he bladders 40' is by L 93', coupling line 95'9 ~ 93 and exhau~t line 95. Thus, as has already bean descrlbed in the previous em-bodi~ents, appropria~e inflation of the bladders 40' are effected by applying infla~ionlcoolant to the input 94 and con~rolled by the raee of e~hau~t through the outlet 95. Since the cryogenic method of cooling is such a shock to the associated components, an appropriate insulator block or layer may be provided between the outer surface of the bladders 40' and the inner surface of the cool-ane coil 76 as indicated by the reference n~lmeral 98. ~iscs 46~ having appro-priate moun~ing and clamplng structures for the respective lines and support structure, like that Eor discs 46 of Figure 4 are also provided Eor this em-bodiment as shown in the Figure~. However, for the ~ake of clarity reference numerals have not been applied to ~hese supports and cl~mps sinc~ numerous variations of same may be actually utilized and practiced and are basically i~ma~erial to the overall successful operati~n of the apparatus. The main requirement being that they be gas and liquid tight so that purging fluid and/
or co~lant may be added ~o space C.
While the purging input and oueput lines have not been sho~ in these Figures in complete detail, again for the sake of clarity, the lines would be fed in through one portion of the devices, such as the center ehereof, as generally indicated by the re~erence numeral 100 in Figure 8. Again, the purging operation and funetions would be as described abo~e for the previous embodiments.

Claims (14)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An apparatus for heat sinking and purging pipes to be welded for use in nuclear systems and the like, comprising: first means for sealing internally the adjacent ends of two abutting pipes to be welded, second means for directing a coolant into the first means for cooling said sealed abutting pipe ends in order to effect a heat sink function in order to keep the temperature of the weld area below that where the dangers of carbide precipitation occur, the first means including inflatable members mountable internally of each of said pipe ends and expandable by the coolant in order to form a tight seal internally therewith and the second means including coolant feed lines and coolant return lines associated with the inflatable members in order to cool the pipe ends adjacent the joint to be welded, and third means for purging the atmosphere in the sealed pipe ends between the inflatable members internally of the joint being welded.

2. The structure as set forth in Claim l, together with a coolant compressor connected to the coolant feed lines by quick connect/disconnect couplings.

3. The structure as set forth in Claim 2 wherein the first means also includes central support structure for supporting the inflatable members thereon and the associated lines therefor, and also the input for the purging means.

4. A purging and cooling apparatus for use with the welding of cylindrical members, comprising: inflatable means for expandable engagement with the cylindrical members to be welded adjacent the weld joint, means for adding inflation and coolant medium to the inflatable means for inflating the inflatable means and cooling the area near the weld joint, the inflatable and coolant medium being the same fluid material, the inflatable means including at least two expandable bladder members which when inflated securely engage with the metal surface of the cylindrical members, and at least one inflation-coolant line provided to each of the bladder members, and separate purge gas means for applying an inner gas to the area between the two inflated bladder members and the weld joint for the purpose of displacing any combustible and contaminated air contained therein .

5. The structure as set forth in Claim 4 wherein at least one exhaust-coolant line is provided to each of the bladder members.

6. The structure as defined in Claim 4, together with separate cryogenic coils provided on the bladder members for contact with the metal surface of the cylindrical members, and appropriate input and output lines connected to said coils for feeding a cryogenic medium through the coils.

7. The structure as set forth in Claim 5 wherein the expandable bladder members are each mounted on a central tubular support member and the inflation-coolant lines run inside the central tubular member for ease of installation and operation.

8. The structure as set forth in Claim 7 wherein the exhaust-coolant lines also run inside the central tubular member for protection and ease of installation and operation.

9. The structure as set forth in Claim 8 wherein the means connected to the inflatable means in order to provide the inflation and coolant medium consists of quick change connect and disconnect couplings between the inflation-coolant lines and the exhaust-coolant lines in order to allow a number of multiple apparatuses to be operated from the same coolant compressor.

10. The structure as set forth in Claim 4 wherein the purge means includes a separate purge line run inside of the central tubular member and supported thereby, and purge gas supply means connected to the external portion of said purge line by quick connect/disconnect coupling.

11. The structure as set forth in Claim 4 wherein the purge means includes a separate purge line run through one of the bladder members and opening into the weld area, and connected to a source of purge gas by quick connect/disconnect coupling members externally of the pipe and bladder member.

12. The structure as set forth in Claim 7 wherein the expandable bladder members each have a central tubular support member, and the inflation-coolant lines run inside the central tubular support members for ease of installation and operation.

13. The structure as set forth in Claim 12 wherein the exhaust/
coolant lines also run inside the tubular support members for protection and ease of installation and operation.

14. The structure as set forth in Claim 13 wherein the means connected to the inflatable means in order to provide the inflation and coolant medium consists of quick change connect and disconnect couplings between the inflation-coolant lines and the exhaust-coolant lines in order to allow a multiple number of apparatuses to be operated from the same coolant compressor.