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' Dec. 3, 194e.
R. Gl. RHOADES
2,412,174
RADIOGRAPHIC INSPECTION METHOÉ
Filed June 24,1946
l
M.
FIIE_E_
2,412,174
Patented Dec. 3,1946
UNITED, STATES PATENT OFFICE
2,412,174
RADIOGRAPHIC INSPECTION METHOD
Russell G. Rhoades, San Francisco, Calif., as
signor to Bechtel Brothers McCone Company,
a corporation of Delaware
Application June 24, 1946, Serial No. 678,783
2 Claims.
(Cl. Z50-65)
2
to freely admit a holder for the radiation source,
The present invention relates to the radio
graphic examination of welds and more par
ticularly to an improved method and apparatus
is permanently sealed.
l
The method and apparatus by which the fore
going objects are attained will be best under
stood from the following description ofv pre
ferred procedure and apparatus, reference being
had to the accompanying drawing, forming a part
for radiographing circumferential welds in pipe
lines and the like.
The radiographic examination of welds in pipe
lines presents problems not encountered in the
of this specification, in which:
~
radiographing of welds in pressure Vessels such
Figure 1 is a perspective view of a preferred
as boilers which are provided with openings
through which either a radiation emanating l0 form of apparatus embodying the present in
vention; the same being illustratedY iny place on
means or a ñlm carrier' may be introduced into
a pipe line;
v
the interior of the vessel. Pipe lines are laid in
Figure 2 is a detail'view of a portion of the
lengths of many miles and are devoid of any such
apparatus illustrated in Figure l; and
` '
(,)peiiiiigsí and this has made it necessary to take
Figure 3 is a detail view illustrating a pre
advantage of theV open end in order to obtain
ferred way of sealing the temporary opening
the necessary access to the interior thereof for
referred to herein.
radiographic weld inspection.
.
In Figure 1 of the accompanying drawing there
is illustrated a portion of a conventional pipe
welds is effected by introducing through an open
line I0 provided with the usual covering II and
end of the line either a film carrier or a radia 20
constructed in sections yjoined together by cir
tion emanating means in the form of X-ray ap
paratus or a capsule of radioactive material, an I cumferential welds such as that illustrated at I2.
According to the present invention, a radio
interruption of construction work on the pipe
Where radiographic inspection of pipe line
graph of any circumferential weld I2 in a pipe
line is necessary for each inspection. If, on the
line I0, which may extend for many miles, can
other hand, both the source of radiation and
> be made Without access to an open end of the
the ñlm are disposed exteriorly of the pipe line,
pipe line. To facilitate the carrying out of the
at least two separate exposures are necessary to
radiographing method of the present invention,
inspect welds even where the pipe is of small
diameter, and methods in which both the film 30 there is preferably pro-vided apparatus of the
character illustrated in Figures 1 and 2 which
and source of radiation are outside the pipe line
comprises an orienting device l5 adapted to rest
are impracticable for other reasons when the
in stable equilibrium on thev curved upper sur
pipe is of large diameter.
face of a cylindrical object such as a pipe line
The principal object of my invention is to
I0. For this purpose the device I5 is preferably
make possible the radiographic examination of
made
in the form of a plate having four legs I6
35
pipe line welds by a single exposure without
by means of which the device may be firmly and
requiring access to an open end of the line.
stably supported on the curved surface of a
A further and more specific object of my in
pipe during any period required for a complete
vention is to provide apparatus facilitating the
carrying out of the radiographing method of my
invention.
The foregoing principal object, together with
other objects and advantages which will appear
hereinafter, is accomplished, ln general, by mak
ing a relatively small temporary opening in the
wall of a pipe line adjacent but spaced from a
circumferential weld therein, and utilizing said
opening to _introduce into the interior of the
radiograph exposure.
^
Secured to the orienting device I5 is a carrier
I'B preferably in the form of a tube secured to the
orienting device I5 by welding as indicated at I9. .
The tube I8 is curved as indicated in Figures 1
and 2 and proportioned so that its lower` end lies
45 outside of the area which the orienting device I5
40
overlies when it is disposed in the operating posi
tion in which it is shown in Figure 1.
When the apparatus is to be used, there is ex
tended through the tube IB an assembly consist
ing of a flexible wire 2l the upper end of which
therefrom to the circumferential weld to be 50 is secured to a handle 22 provided with'a hooked
radiographed and through said weld to a film
portion 23 adapted to engage over the upper end
held on the exterior of the pipe over the weld.
of the tube I8. Attached to the lower end of the
After the necessary exposurel time has elapsed,
flexible wire 2I is a spring 24 the lower end of
the radiation source is withdrawn and the tem
porary opening, which is of only sufficient size 55 lwhich is in turn connected to a second flexible
pipe line a source of radiation; so positioning
the latter as to insure a clear path for radiation
3
4
wire 25 provided with a hook 26 at its lower end.
erably by such means as the hooked handle 33 il
Removably secured to the lower end of the wire 25
lustrated in Figure l, and the temporary opening
by the hook 2B is a conventional radium capsule
is permanently sealed by means such as a screw
21 which is preferably employed as the radiation
plug 44 (Figure 3) inserted in the opening 30 and
emanating means in the practice of the present
welded in place as illustrated at 45.
invention, although equivalent devices such as
What is claimed is:
X-ray emanating means are, of course, well
1. A method of radiographing a circumferen
known in the art.A
tial weld in a pipe line access to which from an
'I'he length ofthe wire and spring assembly 2 I,
open end is impracticable, comprising` the steps
24, 25 is so proportioned to the length of the tube 10 of ymaking a temporary opening in the wall of said
I8 that when the radium pill 21 is engaged in the
pipe line at a point adjacent said weld, introduc
open lower end of the tube I8 as shown, sub
ing radioactive material through said temporary
stantial tension must be applied to the spring 24
opening, positioning said radioactive material in
in order to engage the hook 23~ over the open
the general plane of said weld and substantially
upper end of the tube I8. This spring tension 15 on the axis of said pipe line, exposing to the
serves to maintain the radium capsule 21 in posi
emanation of said radioactive material iilm
tion at the lower open end of the tube I8.
wrapped around said pipe line exteriorly thereof
In carrying out the method of the present in
at said weld, withdrawing said radioactive mate
vention utilizing the above described apparatus,
rial through said temporary opening, and sealing
which is known in the art as a “jig,” a temporary 20 said temporary opening.
opening such as that illustrated at 30 in Figure 1
2. A method of radiographing a circumferen
of the accompanying drawing is made in the'wall
tial weld in a pipe line access to which from' an
of the pipe line at such a distance from the plane
open end is impracticable, comprising the' steps
of the weld I2 as will bring the radium capsule
of making a temporary opening. in the wall of
21 into the general plane of the weld i2 when 25 said pipe line at a point spaced a predetermined
the jig is positioned as illustrated in Figure l with
distance from said weld, utilizing a jig having
the tube I8 extending through the temporary
orienting means engageable withY the exterior
opening 30. It is also to be noted that the tube
wall of said pipe line adjacent `said temporary
I8 is so positioned with respect to the orienting
opening and v radioactive material positioning
device I5 that, when the latter isv in the stable 30 means offset with respect yto said orienting means
position illustrated, the radium capsule 21 is
by the aforesaid predetermined distance and ex
substantially on the longitudinal axis of the p-ipe
tendible through said opening to introduce radio
line. With the device thus positioned,V a nlm 32,
active> material through said temporary opening
which is preferably placed in position before the
and position said material in the general plane Vof
tube I8 is inserted through the hole 33 and which
said weld and substantially on the axis of _said
overlies all of the weld I2 exteriorly of the pipe
line II), will be uniformly exposed and will pro
vide a radiograph of uniform density'showing all
portions of the weld I2.
After the necessary exposure time, determined
in'a manner well known in the art, has elapsed,
the tube I8 is withdrawn from the temporary
opening 30 by lifting the orienting device I5 pref
pipe line, exposing to the emanation Vof said
radioactive material film wrappedr` around said
pipe line exteriorly thereofatL said weld, with- ,
drawing said radioactive material .through Asaid
temporary opening, and sealing said temporary
opening.
,
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' u RUSSELL G. RHOADES. ”
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