Note: Descriptions are shown in the official language in which they were submitted.
CASE 2046
The present invention relates to an orbitary-moving
equi.pment for the automatic welding of pipes, ~hich shall
be referred to hereinunder simply as to "the orbital e-
quipment", which, by producing at the same time b~ means
of two welding lances two superimposecl welding string
beads during each passage, accelerates, improves, innovates
~;~ and makes cheaper the automatic welding operation, both in
the upwards and in the downwards directions, of pipes even
of large diametcr.
The need of accelerating the working cycle ln the
welding operations in the laying of pipelines intended for
the delivery of liquids or of' gases, to the purpose of re-
ducing the costs thereof to more and more competitive val-
ues and to reduce the required time as far as possible,
has in~rolved the development ot' more and more co.plex e~
quipment for pipe automatic welding.
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From the present state of the art highly efficient
orbital equipment are known for the automatic welding of
pipes among which is in particular the one disclosed in our
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prior Canadian Patent N1.046.802 granted on January 23,1979
~ of whose object
: the present Patent Application is a c~nsiderable improve-
ment.
As it is well known, the orbital equipment being the
~: 25 object of the above mentioned prior Patent~ . i.s
es3entially constituted bv a rail positioned and fixed a-
round the pipe in 3 prGdetermined position around the ed~e
to be welded, as well as by a supportin~ plate base f`asten
ed by means of qulclc-fasteni.ng means on to the edges of the
0 said rail, throu~h 'our raced rlheels intended .t'~r slidin~,
and moved along said rail by a driving knurled pinion co-
operating with an edge of the same rail, on said base plate
there being mounted, among others, the welding lance, the
welding wire feeder and the mechanisms necessary for the
adjustment of the position of said lance, as well as for
the swinging thereof in the trasversal direction relative~
ly to said edge to be welded.
Such an orbital equipment, sim ~arly to all other sim
ilar equipments known, allow only one single welding string
bead to be Gbtained during each passage.
In other terms, two superi~posed wel.ding string beads
can only be obtai.ned in subsequent and spaced times, by
means of two d.ifferent passages.
Hence, due to the fact that t.he wel~ing of a pi.pe is
always completed by means of the superimposltion of a cer-
tai.n number of string beads, as many passages are neces-
sary, as many are the beads to be accomplished.
Purpose of the present invent-on is precisely to ob-
viate the limitation said, and to provide therefore an or-
2C bital equipment allowing the welding t~ be obtained with asmaller number of passages.
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By achieving su^h a purpose, also a better qual'ty
of the welds is obtained.
It has been indeed surprisingly experimentally found
that, by effeccing two superimposed weLding string beads
wi~hin 2 short tcime range from e~ch ~'her, i.e., practicai
ly effecting a welding bead when the melting bath of the
underlying bead h s not yet become completely cold, as it
happens with the known art, a ~eld with optimum charac-
teristics is obtained, in that an easier interpenetratiorof the t~o superinlposed bea~is i9 obtai.ned, which impro~tes
the metallurgical characteristics and hence also the tough
ness of the welded joints.
The problem has been hence so]ved by adopting on a
same supporting base plate two welcling lance assemblies
equipped with positioning and swinging actuation devices
as well as with two welding wire feeders, so that by means
of a same single travel of the equipment along the edge
to be welded, two superimposed welding string beads are
obtained, the second bead being effected with a time delay
relatively to the first one which is proportior,al to the
dista~nce on the base plate between the two lances said.
On the other hand, it has been observed always in an
experimental way that the qu~lity of the weld is also a 'un-
ction of the said time delay, which must therefore be pre-
cisely determined in each case, so that, in order it to beossible to control this phenomenon too, it is necessarJ to
~ envisage the possibility of varying the time interval e-
-~ lapsing between the formation of two subsequent welding
beads, so that it be possible to start the second cycle
at that precise moment of the first cycle whereat the con-
ditions of temperature and of solidifying conditior.s of the
weldi~ material and of the same pipe are the most suitable
to start said second cycle.
~- ~ To that purpose, the welding lances are not mounted
2~ on fixed positions on the supporting base plate, but in
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such a way that the distance, .n the circumferent:ial di-
rection of the rail, of a lance relatively to the other
one can be ~aried as desired, and consequentl~ the sai.d
time delay can be varied as desired, and this is achiev-
0 ed by si!nply fastening the t~o welding syste~s by m~ansof bolts housed within slots, which e~tend in the circu~!-
~ g
ferential directi.on of the same rail.
As~ moreover, the adoption of two complete and auto-
nomous welding systems on a same base plate, whose siæe
of course must not be increased in order not to increase
the o~-erall dimensions, which would impair an efficient
fastening on to the rail and would make more complex the
welding of a circular joint~ involves such an accumula-
tion of elements on the said plate, as to render dif-
ficult the operations of inspection and o~' cleaning of the
we].ding lances and of the lower parts of the mobile equi~
ment without it being necessary to di.sengage the whole
structure from the fixed rail, according to another feature
of the invention the two said welding systems , instead of
being mounted on the said supporting base plate, are mount-
~5 ed on a second supporting plate, whlch is hinged on to anend of t~.e said base plate, and is held in correspondence
of its other end by a locking hook mounted on sai.d support-
ing base plate. In this way, by disengaging the said lock
ing hook, it is possible to swing apart the said second
plate and thus to render easily accessible the lances and
the lower parts of the movable equipmerlt mentioned.
Summarizing, the orbitary-moving equipment for the
automatic welding of pipes, comprising a fixed portion or
rail positioned and fixed around the pipe in a predetermin-
2~ ed position relatively to the edge to be welded, as wellas a movable portion constituted by a supporting base plate
fastened with quick-fastening means on to the edges of the
said rail throuæh four raced wheels for sliding, and driven
~ along said rail by a drivir1g knurled pinion cooperating
:~ 30 with an edge of the same rail, on which base plate a weld
in~r systeln is mo~lnted, constit~lted by a block supportirlg
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the welding lance comprehensive of the ~evices necessar~
for the adjustment of its positioning and for its swing-
ing motion, as well as the feeding device of the welding
wire, comprising the welding wire bobbin and the mechanism
for delivering the same wire, is characterized according
to the present invention in that it is provided with an
analogous second welding system mounted in a parallel
~ , position ~o the first welding system on said base plate?: so that the two welding lances are positioned parallel
to each other along the edge to be welded, the two said
welding systems being fixed at a mutual adjustable dis-
tance by fastening the said supporting blocks with bolts
housed within slots e~tending in the circutnferential di-
rection of the same rail, provided on a second supp~rtlng
plate which is in its turn hinged in correspondence of an
end thereof on to an end of said supporting base pla'~e
and held in correspondence of its other end by a locking
hook for the locking of said supporting base plate.
Moreover, as, due to the limited space available,
: : 20 the addition in a parallel arrangement of a ~econd weld
: ing wire bobbin for feeding the second lance would make
i.t impossible the reloading of the wire on the bobbin
of the first lance7 according to another feature of the
: present invention, the welding wire bobbin for said second
lance is rotat,ably mounted on an arm articulated and kept
~ in its position by a locking key.
,~ In such a way, by unlocking the key, said second bob
bin can be swung apart, thus allowing the first bobbin
~; to be inserted inside its housirlg.
~0 The invention is now better clarified with reference
to the drawings attached, which illustrate a preferred
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form of practical embodiment, given to only exemplifying
and not limitative purpose, in that it shall-be always
possible to introduce technical of structural modifications
always within the spirit of the present invention.
In said drawings:
Fig. 1 shows in a partial perspective view an orbit-
al equipment according to the invention, mounted on a
pipe to be welded;
Fig. 2 shows in partial perspective view the orbital
equipment of Fig. 1, with the weldirg systems in their
swung-apart position;
Fig. 3 shows in a partial perspective vie~ and on
enlarged scale the detail of the mounting system of the
second welding wire bobbin, it too according to the in-
vention.
Referring to the drawings, with 1 the edge to be weld-
ed is shown of a pipe 2, on to which at a predetermined dis
stance relatlvely to said edge 1, a circular rail 3 is
mounted and fixed, leaning on to said pipe by means of
pin-shaped spacers 4.
On the rail 3 a supporting base plate 6 is then fas~en
ed, with moving possibility, through ~four slide raced wheels
5, on an end of whose supporting base plate 6 a second
supporting plate 8 is hinged, by means of the rotation
pin 7, such second supporting plate 8 being kept into
contact with the base plate 6 by means of a quick-release
locking hook 9, which, with being mo~nted at the other
end of said base plate 6, causes its hook 9' to interact
;~ with the upper surface cf the other end of the said sec-
ond supporting plate 8 (see speci~fically Fig. 1).
~aid second supporting plate 8 is moreover provided
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with pairs of slots 10, extending in the circumferential
direction of the rail 3, within which two supporting
blocks, respectively 11 and 11 ' are bolted in paral-
lel arrarlgement to each other. Said blocks 11 and 11',
whose mutual distance is clearly adjustable as de3ired by
taking advantages of the length of said slots 10, support
two wel~ing systems complete, autonomous and positioned
parallel to each other, of which the second one shall be
hereinunder marked wit'n the same numbering as of the first
one, but provided with a prime.
More specifically, each block 11, 11' supports, with
the possibility of the adjustment thereof in the axial d
rcction of the pipe 2 by means of the guide of the knob
12, 12', a frame 13, 13' which is in its turn vertically
adjustable in the radial direction by means of the knob
14, 14'. Each frame 13, 13' ~upports then, with the pos-
sibility of swinging movements, whose stroke can be adjust-
ed by means of the knob 15, 15', a structure 16, 16' onto
which a welding lance 18, 18' is fastened, by means of a
projecting arm 17, 17'.
~he two lances 18, 18' are positioned in a parallel
arrangement relatively to each other along the edge to
be welded 1 (see specifically Fig. 1~ and are fed with
the welding wire 19, 19' which is extracted from its
relative bobbin 20, 20' by a driving mechanism 21, 21'.
Finally, the bobbin 20l of the welding wire 19' for
; the second lance 18', as it can be clearly seen in Fig. 3,
is mounted on an arm 22 hinged in 23 on to a bracket 24
which is solid with said bloc'~ 11'.
3 Said arm 22, which allows the second bobbin 20' to
be swung apart to the purpose of an easy replacement of
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the first bobbin 20, is then kept f`ixed in its position
by a locking key 25 which is screwed on an extension 26
of' said arm 22.
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