Welding process and apparatus

In a welding procedure for joining of adjacent, possibly partially enclosed metal components, such as pipe sections, wherein the welding procedure can be of a gas tungsten arc type such as a heli-arc type, or similar process, and wherein oxidation of metal frequently occurs within the components at the joinder point due to presence of oxygen in the region of weld during the welding procedure; introducing under pressure and at least initially pressure blowing, at a relatively high pressure, an inert gas into the interior of the components in a substantial swirling and interior surface wiping motion. The inert gas is blown through the components, from the entry end, beyond the weld region to rapidly, and substantially completely remove from the interior and weld region, any oxygen or other possible deleterious gas or material. Subsequently a lower pressure introduction of gas will serve to maintain the interior free of oxygen and the like. This procedure permits a clean, rapid welding of the elements in the absence of a build-up of undesired metal at the weld or juncture point, or undesired disturbance of the weld puddle which could cause defects in the weld.

The invention broadly relates to joinder of two abutting sections of metal 
such as pipe by a gas metal arc, gas tungsten arc or heli-arc process 
while preventing an undesired metal oxide build-up on the inside of a 
pipe, for example, at the weld point. Other similar welding procedures are 
also contemplated. 
The metal being welded, and preferably adjoining sections of pipe, can be 
of stainless steel or other exotic type metals such as carbon-steel, 
Hasteloy, Inconl, Monel or similar materials. When welding such materials 
the heat created by the welding procedure will normally, due to high 
temperatures involved, melt the material of the pipe sections and/or added 
stick weld material. The heat and melting penetrates through the material, 
and tends to cause an accumulation of oxidized metal material on the 
interior of the pipe due to oxygen or can affect the weld puddle in an 
undesirable manner. This frequently results in a possibly inferior weld 
and/or a disruption of a smooth interior pipe surface. 
The present invention is directed to overcoming these problems heretofore 
encountered. 
While the problems have long been in existence and understood, there has 
not been a satisfactory solution developed. As examples of prior art 
attempts to overcome the problems, several proposals have been advanced 
and U.S. patents have issued on the processes and apparatus. These prior 
patents which constitute prior art and which are incorporated herein by 
reference include the following: 
W. R. Ramsaur U.S. Pat. No. 2,177,995; Oct. 31, 1939 
R. T. Pursell U.S. Pat. No. 2,819,517; Jan. 14, 1958 
E. W. Williams et al U.S. Pat. No. 2,874,263; Feb. 17, 1959 
T. McElrath et al U.S. Pat. No. 2,905,805; Sept. 22, 1959 
While other methods and procedures have been attempted, none have been 
completely satisfactory. 
SUMMARY OF THE INVENTION 
The present invention accordingly is broadly directed to a welding process 
and apparatus for welding of adjoining or adjacent pieces or sections of 
metal, such as metal pipe, wherein a flow of inert gas is introduced into 
an end of the pipe under substantial pressure initially and in such a 
manner, by a particular apparatus structure, as to create a high pressure 
swirling of the inert gas in the interior of the pipe with a resultant 
interior surface wiping motion. 
The inert gas is blown through the pipe interior and exits therefrom. The 
action of the inert gas serves to rapidly and substantially completely 
remove from the interior of the pipe, and primarily the weld region, any 
oxygen or other possible deleterious gas or material. This permits a clean 
and rapid welding of the elements in the absence of a build-up of oxidized 
metal interiorally of the pipe at the weld or juncture point. A 
disturbance of the weld puddle, which could also create problems and 
perhaps inferior welds, is likewise eliminated by the present process. 
The process is primarily usable in connection with stainless steel pipes or 
piping consisting of what is known in the art as exotic metals, and 
wherein the welding is effected by a type such as a gas metal arc, or gas 
tungsten arc, and the like, which normally results in the material of the 
pipe, and/or a weld rod if used, melting and a resultant penetration of 
the melted material from the exterior to the interior can take place. In 
the presence of oxygen in the pipe interior there is a strong likelihood 
of formation of oxidized metal. This is undesirable and the present 
invention eliminates this possibility. 
Following an initial insertion of the inert gas under relatively high 
pressure and following an interior cleaning action, a continued flow of 
inert gas can take place to eliminate areas of low or back pressure which 
can result in undesirable interior pressure conditions. 
It is a principle object of the present invention accordingly to improve 
welding procedures and techniques, particularly as applied to partially 
closed sections of metal being butt welded, such as pipe sections, and to 
eliminate problems caused by the presence of oxygen and other deleterious 
gases and/or materials within the pipe sections. 
In accomplishing the new and improved end results of the invention, inert 
gas is introduced into the interior of the pipes by means of a nozzle 
having a plurality of exhaust holes or openings therein so arranged as to 
introduce the inert gas in a swirling or vortical type of flow serving to 
wipe the interior surface of the pipe and exhaust deleterious gases and/or 
materials from the pipe, and particularly at the point of welding 
juncture. The nozzle also includes one or more openings which will serve 
to remove such gas or material from the area or region of introduction of 
the inert gas, i.e., from the introduction end of the pipe. 
The apparatus and procedure subsequent to initial high pressure 
introduction of inert gas is then subsequently controlled to maintain an 
idealized welding condition within the pipe sections. 
Still other objects and advantages of the present invention will become 
readily apparent to those skilled in the art from the following detailed 
description of an embodiment of the invention, wherein there is shown and 
described only a preferred embodiment of the invention. The disclosure is 
simply by way of illustration of a best mode contemplated currently for 
carrying out the invention. 
As will be realized, the invention is capable of other and specific 
embodiments and procedures, and such modifications are to be considered as 
within the scope of the invention. Accordingly, the drawings and 
description are to be regarded merely as illustrative in nature, and not 
as restrictive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now in detail to the drawings, FIG. 1 discloses a prior art 
method of welding including an attempt to evacuate or purge the interior 
of adjoining pipe sections to be welded of oxygen or the like. The two 
pipe sections are generally designated 10 and 12, respectively. It will be 
noted that the adjacent pipe ends are slightly beveled at 10a and 12a, as 
commonly used in the art for facilitating the welding together of the 
sections. Weld neck flanges are normally used and in FIG. 1 a weld neck 
flange 14 is shown affixed to one end of pipe section 10. A point of butt 
weld juncture between pipe sections 10 and 12 is generally designated at 
16. In the known, old process, a hose or tube 18 is inserted through an 
opening in a cap plate 20. An inert gas such as nitrogen or argon or the 
like is passed through tube 18 and exits, as indicated at 22, into the 
interior of pipe section 10. The inert gas as so inserted has a tendency 
to roll on the interior walls of the pipe as indicated by swirls such as 
at 24. This results in a pressing of air, including oxygen, in the 
interior of the pipe against the walls and can result in leaving small 
areas or sections such as at 26 of air trapped in the pipe. It is also to 
be noted that when utilizing the prior art method as shown in FIG. 1, 
there are regions of trapped air at 28 behind the effective portions of 
the inert gas flow. In the old attempt to purge air from a pipe, since it 
leaves trapped air in the pipe, there are bits or small amounts of air 
mixed with the incoming inert gas. This trapped air and resultant action 
will affect a weld puddle generally indicated at 30, and since the pipe 
material and/or material of a filler rod will tend to flow to the interior 
of the pipe at the weld juncture, can result in creation of oxidized metal 
as schematically indicated at 32. 
When utilizing the old method of attempting to purge a pipe, the 
introduction of the inert gas as shown at 22 must run for a substantial 
period of time with a resultant expenditure of money in time and gas 
consumption. Furthermore, the inert gas, such as argon or nitrogen, is a 
heavy gas and will tend to fall away from the pipe interior due to gravity 
in an area as at 34 and this occurrence can take place in other areas. 
This tendency of the inert gas to fall away from contact with the interior 
of the pipe is the result of inertia and the heavy gas used. It will 
accordingly be seen that, especially in the weld area, there is a 
possibility of inferior welding and/or the creation of undesirable metal 
oxide build ups. 
These drawbacks in the prior art are overcome by the present invention. 
Referring initially to FIG. 2, two free pipe sections 36 and 38 are shown 
in adjacent or abutting conditions, and are to be welded by means of a 
heli-arc, tungsten gas arc or metal gas arc welding technique. Pipe 
section 36 includes a weld neck flange 40 and adjacent ends of pipe 
sections 36, 38 are again bevelled as generally indicated at 42. A welding 
torch of an appropriate type is shown at 44. As is normal in this type of 
welding procedure, a flow of inert gas at 46 is used for cooling and to 
maintain tungsten, or metal filler rod 48 material, from excessively high 
and injurious temperatures. Such procedures are well known in the art. 
The present invention departs from the prior art in the manner of insertion 
of inert gas into the interior of the pipe. Again referring to FIG. 2, a 
hose or tube 50 passes through cap 52 and a flow of inert gas under 
pressure is run or passed through the tube 50. Mounted on inner end 54 of 
the tube, within the pipe section 36, is a cap or purge device generally 
designated 56. Preferably, as shown in FIGS. 3 and 5, the inner end of the 
cap 56 has a closed end 58, and the cap can be internally threaded at 60 
for attachment to the tube 50 in an obvious manner. 
This cap or purge device 56 has a plurality of gas flow openings or holes 
therethrough as shown in FIGS. 2-6 inclusive of the drawings. As shown in 
the drawings, the closed end 58 has three holes or openings 62a, 62b and 
62c passing therethrough. These holes are drilled at diverging angles and 
spaced from the longitudinal axis of the cap, and as shown, at an upward 
angle of approximately 30.degree. to 40.degree. from a longitudinal plane 
passing through the axis. A greater or lesser number of holes, and of 
varied positionment, can be incorporated, and the exact angle at which 
drilled can vary somewhat so long as they will accomplish the desired end 
result to be hereinafter discussed. The holes therefore are outwardly 
spaced from the central longitudinal axis and are not drilled as, or 
along, radii extending from the central axis. The arrangement is such as 
to cause a swirling or vortical motion to the inert gas exiting through 
these end holes, and directed toward the welding location and the exit end 
of the pipe sections. This action is hereinafter further described. 
In addition to the end holes, a plurality of holes or openings are formed 
through the sidewall of the cap. As shown, there are four openings 64a, 
64b, 64c and 64d. The holes 64a, 64c and 64d can all be drilled at the 
same angle, though not necessarily, with respect to the longitudinal axis 
of the cap, and most are in an upward inclination toward the closed end 58 
of the cap. The number of holes can also vary, as may be functionally 
desireable. Three of the holes 64a, 64b and 64d, as shown, are drilled at 
a non-radial angle with respect to the central longitudinal axis and are 
so formed and disposed that inert gas exiting therefrom will take a 
similar swirling or vortical motion as that exiting from the end holes. 
All the inert gas exiting from all the holes will tend to operatively 
merge or join in this action, and tend to fill the pipe sections interiors 
with a swirling or vortical flow of inert gas moving toward the exit end, 
and additionally to cause a wiping action along the interior pipe surfaces 
or faces. The remaining hole 64c in the sidewall, while having the same 
angular disposition as the others through the side as to cause a swirling 
motion around the cap, is not drilled at an inclined angle toward the end 
of the cap. This hole 64c is at right angles to the longitudinal axis of 
the cap as shown in FIGS. 5 and 2. This positionment of opening 64c is to 
cause a flow of inert gas at right angles to the longitudinal axis of the 
cap and directly toward the interior sidewall 66 of the cap, serving to 
flush air from behind the nozzle as indicated by arrows 68. This flow 
additionally overcomes a low pressure gas area resulting from the forward 
flow from the other holes. 
The inclination of the end and other side openings and their arrangement, 
will create a swirling or vortical flow of the inert gas, as indicated by 
arrows 70, the same numerical designation being applied to these currents 
or flow paths of the inert gas from the various holes which join in the 
swirling motion, and as shown at 72 in FIG. 2 will tend to wipe the 
interior surface 66 of any air thereon. The angular disposition of exited 
gas, when it hits the interior wall of the pipe, tends to bend the flow 
around in the swirling motion. 
If desired, the holes can be drilled in a staggered manner so long as they 
are so aligned that gas flow from each will catch up to that from the 
others and cover the interior wall of the pipe. 
The nozzle can be formed of heat resistant plastic since it is in a 
position where it will not be exposed to extreme welding heat. 
With the substantially violent whirlwind or vortical action, heavy gas will 
not give way to gravity as quickly as it would with the old straight in 
method as shown in FIG. 1. 
The sizes of the holes can vary, as also their number. As an example of a 
particular use, and as shown in the drawings, the pipe can be six inches 
in diameter, with the cap approximately 1/4 inch thick, and the various 
holes or openings approximately 3/32 inches in diameter. Initially the 
inert gas will be inserted at a rate of approximately 60 cu. ft. per hour 
for a 10 foot pipe section, and thereafter reduced substantially to a 
range of about 20 cubic feet per section for a minimized flow through the 
pipe. 
A closure cap at the far end of the pipe will be provided with a weep hole 
to permit flow of the inert gas to the exterior. In the embodiment shown, 
with the end of the pipe capped off and the nozzle as formed placed as 
shown, the inert gas being introduced would, as exited, be pointed in 
seven different directions at the same time. 
The nozzle can have the holes drilled to point in a clockwise or 
counterclockwise direction and in use can cause a whirling or vortical 
flow pattern in pipes 2 to 24 inches in diameter, 30 feet long, and can 
bring gas purity up to 100% in 50% of the time required in the old method, 
with increased efficiency and maintain a more even blanket of inert gas 
against the interior wall surface of the pipe. 
The structure, function and advantages of the present invention will be 
readily understandable from the foregoing description of a preferred 
embodiment when taken together with the drawings. 
Many other possible variations in specifics of components or details of the 
invention will be apparent to those skilled in the art. While in the 
present disclosure, there is shown a preferred embodiment of the 
invention, it is to be understood that the invention is capable of changes 
or modifications without departing from the spirit and the scope of the 
inventive concept as expressed herein.