Note: Descriptions are shown in the official language in which they were submitted.
~Z~97~
This is a divisional of Canadian Patent Application
Serial No. 387,215, filed October 2, 1981.
HOLUGRAM APPARATUS FOR DETECTING FLAWS AND PHOTOGRAPHIC STATI9N
Tec~ical Field
__
This ~n~ention is in the field of non-destructive
~sting.
Back~round of the Prior ~rt
It is well kno~n to use i~terferometric holography
in non-destructive testing. It is also known to develop 8
photographic film used in ~uch te~ting in situ in order to
expedite t~e te~ting procedure. Reference may be had to U.S.
Patent 3.749,702. This patent discloses water in the
developing chamber during the imaging of the film. The in
situ development of film in apparatus for exposing and
developing film and projecting the image of the developed
film is disclosed in ~.S. Patent 3,200,724. In ~his
patent wa~er is used in the developing chamber to improve the
transmission of light throu~h the film holding device and to
eliminate the drying of the film after development and prior
to protection.
Brief Summar~ of the Invention
This invention concerns hologram apparatus of
great flexability and convenience for use in double exposure
and real time holographic interferometry. It concerns
a superior film
--2--
handling and developing s~ructure. I~c overcomes a seric~us
problem inherent in the prior art in that it ::an be used in
any spatial orientatiorl.
In accordance with the invention, there is
provided a ph~tographic station f~r supporting a photo-
sensitive medium especially for use in hologram apparatus
for detecting flaws. The ph~tographic station tog~ther
wi~h the photosensitive medium fonms a developing chamber with
a transparent face hav~g a depth ln the range of from about
1~ .005" to ab~ut .12~", preerably of from about .005" to ~bout
~080". l~ae developing chamber has a periphery with a conto~ir
which always changes at an an~le greater than al~out 115, ad~ran
tageously greater than 12~, and is preferably ~:ircular.
Ass~ciated hyd~aulic: equipmen~c supplies and removes fluid :Erom
15 the developing cham~erO A laser supplies ct>herent light for
the article to be tested for reflection to the photographic
statio~. A reference beam is directed ~o the photographic
~tation. For use in inspecting pipe in the :i~ield, the apparatus
advantageously has a housing and a pair ~f saddles each ha~in~
different diameter pipe receiving portions and a strap cecuring
~ystem. The p-notographic station can develop the photose~sitive
medium in situ and may be used in any spatial orientation. The
invention also e~prises the photcgraphic station per se without
the laser.
Due to the eonstructlon of the de-Jelopin~ chamber,
capillary action causes a liquid entering it to force out all
fluid already in the ehamber irrespective of spatial ori~ntation.
This insures that there is no premature film development by the
presence of a residual amoun~ of processing liquid and that the
30 devel~ping liquid is not diluted by the flushing liquid ~t any
point in th~ cha~ber. The eontour of the de~el~pin~ chamber
periphery insures that adhesion between the cha~ber
and a c~ntained liquid will not result in a p~cket of ~iquid
bein~ retained in the chamber whe~ it is desired to evacuate it.
~ 35 The developing chamber minimizes the ~m~unt of developing liquid
t re~uired f~r processing,
.
,
,
.
'7
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Brief Descriptlon of the Drawin~s
Fi:gure 1 is a ron~ elevation of the h~logram
apparatus of the inlJen~cion wi thout ~che housirlg;
~ igure 2 hS a Tighthand eleva~ion of ~che apparatus
5 of Fi gure 1 without the housing;
Figure 3 is a plan ~iew of ~he apparatus of Figure 1
without the h~usin~g;
~ igure 4 is a view illustTa~ing the use of ~ne of
the securing saddles;
Figure 5 is a view illustrating the use of one of
the securing saddles;
Figure 6 is a lefthand eleva~ional view of the
apparatus of Figure 1 w~thout the housing;
~ igure 7 is an enlar~ed plan view of ~he photographic
lS station;
Figure 8 i~ a secti~n taken on the plane indioated
by the line 8-8 i~ Figure 7;
Figure 9 is a diagrammatic view of the hydraulic
system of the device of Figure l;
2Q Figure 10 is a diagrammatic view of the mi~roprocesscr
and associated elements of the apparatus of Figure l;
Figure 11 is a front elevation of the apparatus of
Figure 1 with the h~using in place;
Figure 12 is a plan view of the apparatus as shown
25 in Figure 11;
Figure 13 is a sec~ion taken on the plane indica~ed by
he line 13-13 in Figure 11;
Figure 14 is a section partially broken away on the
plane indicated by the line 14 14 in Figure 11;
3Q Figure 15 is a plan view of an alternative trans-
parent plate and gasket;
Figure 16 is a plan view of ~n al~ernative trans-
parent plate and gasket; and
Figu2e 17 is a plan view of an alternative trans-
3~ parent plate and gasket .
7~
~,
~etailed Description
-
H~logram apparatus 2 in accordance wi~h the inven-
tion has a frame 4 to which is secured a pair of saddles 8, 8
eaeh having an arcuate recess 10 adapted ~o reeei~e a pipe 12
5 (Figure 2). ~ach saddle B a~so has a psir of recess portions
lDA and 10B on an arc of much greater radiuc than the radius
of recess 10 to acco~modate large diameter pipes. In Figure
4 broken lines 12A represent piyes of varying diamete~s beariag
on saddles 8 at points lOC and lOD. F~r larger pipe a greacer
10 span of bearing is achieved as is illustrated in Figure 5
where broken lines 12B represent larger diametgr pipes bearing
on addles 8 at 10E and 10F, the wider span giving a more
~table ~uppcrt for ~e saddle 8 and apparatus 7, Pipes of
the ~ize of pipe 12 and smaller are accommodated in recess 10
15 of each saddle 8.
Each 6addle 8 has a yoke 18 secured thereto pivotally
as indi cated at 20, One end 24 of a strap 26 is secured to yoke
18 as indicated at 28, A .~econd yoke 32 is pivotally ~ecured
thereto at 34. ~ yoke 36 having a pin 40 is piv~tally secured
20 t~ lever 32. One end 44 ~f a second strap 46 is secured to pin
45. A conventional adjustable buckle 48 removably connects
~traps 26 and 46.
A laser 6~ is secured to frame 4 and is connected
to a power supply indicated at 62 ~Figure 1). ~aser ~0 may
25 be ~ for example, a helium-neon laser having an ou~put of ten
miliwatts. Any laser known to the prior art for holo-
~ 2~ 7 ~
.
--5--
graphic non-d structive testin~ such as a Y~G laser, ~
kryptDn lasPr, a C02 laser or a nitro~en laser may be used.
A continuous ~ave laser operating in the TEM mode should be
used. Advanta~eously, the laser w111 have a power outpu~
fro~ about 1 to about 20 miliwatts.
Before leaving the laser 60, the beam is expanded
by way of a suitable lens, e.g. a standard microscope
objective lens, located at the front end 61 of laser 60.
The expanded beam from laser 60 is then directed
to mirror indicated at 64 (Figure l)which direc~ the beam ~wardly
to a mirror 66 which direct~ the beam to mirror 68 ~ecured
to ~ metal plate 70 whic~ in turn is ~ecured ~o a rod 72
pi~otally mounted trans~ersely on frame 4. A handle 78
~ntegral ~i~h rod 72 is used for pivoting o mirror 680 A
: 15 -magnet 79 ha~ing a chamfered face 80 and attached to housing
81 ~hD~n in Figure l in phanto~ holds pl~te 70 and mirror 68
~ in position shown in Fi~ure l. In this position mirror 68
:~ .refle~ts t~e laser beam downwardly tc a pipe coupling 82
coupling pipe-12 to a pipe 84. A portion of the laser beam
is reflected from coupling 87 upwardly to a photographic
~tation 86. A portion of the laser beam is reflected from
mirror 68 to a reference beam mirror 90 and thence to photo-
graphic station 86. ..
~: - The laser beam is cGntrolled by a shu~ter 94 havi~g
an arm 96 :(~igure 2) adapted to.block the light emanating
from the lasex. Arm 96 is serured to a pivot plate 98 ~Fig-
ure 2) biased t~ the shutter closed position by an extension
spring 100. Pivot plate 98 is actuated by a solenoid 102
which when actuated opens the shutter 94 to permit the passage
of li~ht from the laser to mirror S4.
Photographic station 86-has a transparent plate 120
~Figure 8) of, for example; a syn~hetic resin such as an acry-
lic, polycarbonate? fluoro or ~olystyrene resin. Plate 120
is ~ecured to fra~e 4 o~er an openin~ 122 in frame 4,
.circular gro~e 124 contains z ring gasket 126 of for example
~u~ber which is circular in cross~ectipn and extends siightly
abo~e t~e top 128 of pl~te 120,. A pair of bars 130 and 132
are secured by an ~dhesive to the top 128 of plate 120. A
transparent plate 136 of, for example, a synthPtic resin such
--6--
a~ c)ne of those listed above, overlies pla~ce 12a between bars
130 ~nd 132 and is`~ivotally secured 'LO a yo~ce ~rame 149 by
pins 142 ~ 144 !~igure 7~ oke :L40 is pivotally ~ecured to
~l~ck 132 by pin~ 146, 14~. The cross bar 152 of yoke 140 ~
5 is adhesi~ely secured ~o a plate 154 which in ~urn is ad-
hesively secured ~o ~ block 156 through which passes ~ ~crew
157 whieh pivc~tally conneet~ bloclc 156 ko a plunE~er 158 of
~olen~id 16~. P~ un~ger 158 is loosely received in opening 161
in block 156. Solenoid 160 is mounted between standard 162
10 ~ ~ ~plit ring 16B ~ecured ~n ~r~ove 170 in plunger 158 act~
tD bias pl~ger 158 downwardly to in ~urn b-Las pla~ce 136 down-
~ardly .
A conventional ~ilm cartridge 18 0 (Figure 7 ~ i; ro
tatably supported by a cartridge holder 182 mounted vn frame
15 4 and supplies film 184 which is wound onto a reel 186. Advan-
tageously, film 184 i~ a high resolu~ion ilm ~uch as Kodak*
649F of ~he Eastman Kodak Co. Reel 186 is mcunt.ed for rotation
on cone 188 m~unted on a spring metal tab 190 and a hub 194
which i~ splined to a ~pindle 196 driven by m~or 200. Film
2D 184 lies between plate 136 and gasket 126. Film 184, gas~et
126 and plate 120 form a very shallow developing chamber 210.
The chamber 210 will have a dep~h (i.e., the distance between
the emulsion side of film 1~4 and plate 120~ of fr~m abDut .005"
to about .125", preferably fr~m ab~ut .005" to about .080'l.
25 Advantageously the depth will be from ab~ut .~15" to ab~ut .025".
The thus formed chamber is circular.
The plate 120 ha~ a supply conduit 214 tFigure 7) ha~ing
~ reduced ~mall diameter p~r~ion 216 in communication with chamber
210 and a dischar~e conduit 218 having a reduced small diameter
30 p~rtion 220 in communication with chamber 210. ~he reduced
diameter portions 216 ~nd 220 communicate with chamber 210 d-
~acent the periphery and diametrically opposite to each other.
The diameter of these conduits is ~mall to inhibit liquid fr~m
flowing out of ch~mber 210 when no pumps are running. Advan-
35 tage~usly tney will have a diameter in the range of from about1/32" ~o ab~ut 7/32'~ with the portion 216 preferably having a
diameter larges ~han that of portion 220.
*TrademarX
Cc~nduit ~14 is c~nnected tc> a line 230 tFigure 9)
t~ which is connected a ~en~ line 232 cc~ntaining a check
ua~ve 234 t~ p~event f~luid :Erom passing through the verlt
line ~hen it is being pumped ~co chamber 210. :I,ine 230 is
5 connected by l;ne 236 Lo a valve 238 and a valve 240. Valve
238 is cc~nnected to line 244 and 1 ine 246. Valve 238 is a
t~ positi~rl valve connec~cing line 244 ~co either line ~36 or
line 246 j the normal positlon bein~ ~he connec~ion t~ line
246. LiTae 244 h~s a rheck ~alve 250 and is c:Qnnected to a
10 pump 252 which i~ connec~ed ~y line 2~4 ~o a ~upply tanlc 256
"naving a veD.t 257 and c9ntaining ~ater 258. Line 246 cvn-
tains a check. valve 264 and is comlected co drain line 266
which discharges into a ~ank 268 having a ~ent 269. L1nPS
244 and 266 are long and flexible to permit locating pump
15 252 and tank~ 256 and 2$8 at a remote loczti~ separate from
~he main p~rtion of apparatus 2.
Valve 240 is connected ~o line 272 whi~h is con-
nected to l~ne 246 and is connec~ed to line ~74. Valve 240
is a tw~-~ay val~e connecting ~ine 274 to either line 272 or
20 line 236 with the connection to line ~72 being ~he normal
position. Line 2~4 contains 2 check valve 276 and is con-
nected to a pump 278 which in ~urn is connec~ed to a line
280 which is adapted to pick up a developing-fixing bath
~nobath) 28~ from a tank 2~4 which has a vent 286. A
25 typical monobath is Xoaak ~;48 of the Eastman Kodak Co. Line
274 is long and flexi.ble so that pump 278 ~nd tank 284 can
be placed at a remote locatic~n away from the main part of
apparatus 2.
Discharge conduit 2~8 is connected to line 29û
30 whirh is connected to pump 292 w~ich discharges into line 266.
Pump 292 is, for example, a rubber vane type pump whi.ch will
nGt pass fluid when stopped~ A line 294 containing check
~al~e ~96 is in parallel ~ith pump 292 to bypass pump 292.
A ~uic~ diseonnec fitt;ng 295 OEi~ure 2) i~ provided for
35 lines 244, 266 and 274.
Referring to Figure 10, the apparatus 2 is energized
by a 12-v~lt .ctery indica~ed at 300 t~. positive sidP o:E
~hi rh is cDnnected ~co a line 310 ct7ntainiTIg a main power swi~cch
~ll2 and the negative side ~f which is connected Lo a line 314.
Pow~r supply 62 is connec~ed to line 310 by line 316 and is
connected to the negative side s:f bactery 300 through lines
31e, 320 an~ 314 Laser 60 is oonnected to the power supply
6~ by lines 322 and 324. A ~cimer swi~ch 33U having a momen-
'cary stsrting sw tch 334 controls shutter st~lenoid 102. Timer
330 is c~nnec~ed by llne 332 t~ line 3~0 a~d lby line 336 to line
~L~ 310. Timer sw:atch 330 con~crols shutter solenoid 102 being oon
nected there~co by lines 340 and 33~. Solenoid ln2 can also be
ac~ivated by olosiIlg ~;witch 400 in line 310 which is connected
to line 338~ ;lIne 340 being c~or~ec~ed t~ line 332 ~hrough line
346. Timer 330 i~ controlled ~y ~ photo-electric cell shown
15 a~c 350.
A~ microproce~sor 302 is programrned ~co carry out the
sequential operations required~ The use Df microprocessors for
sequencing operations is conven~ n~l. Other means such as a
mechanical stepping switch may be employed~ Microprocessor
20 302 is onnected ~o line 310 by lisle 360 and line 314 by line
352. As indica~ed by br~cen lines 370, 371s 372, 374 and 376
p~wer to m~tor 200, solenoid 160 and pumps 252, 278 and 292 is
respectively controlled by microprocess~r 302. Likewise broken
lines 380 and 382 indicate the control of power to valves 238
25 and 240 respectively by microprocessor 302. A quick discon-
nect fitting 386 ~Figure 2~ is provided for connec~ing the nec-
essary lines to motor 200, solenoid 160, solenoid 102 and power
supply 62 to the remaining circuitry.
Operations
3D The operation of the appafatus 2 will be evident fro~
the foll~wing description. The apparatus 2 is mounted on pipe
1~ with the pipe received in arcuate p3rticns 10 of saddles 8
and is secured by straps 26~ 2~
Fo~ start-u~ of the apparatus ~ film cartridge 18û
is placed in film holder 182 (Figure 2) and film 184 is threade~
between ~asket 126 ~nd plate 136 while solenoid plunger 15~ is
held upwardly by hand to raise plate 136 a-bove gasket 126.
The ilm is threaded into reel 186 and
97~
plunger 15~ ~s released permil:ting pla~ce 136 to hold the
film securely against ~asket :L26.
Switch. 312 is closes~ to ener~giæe lase~ 6D and pro-
~ide power to mic~p~rcess~r :302. Shutter 94 keeps the laser
5 beam from reaching mirror 64.
Momentary ~witeh 30:L is closed to ini~ciate the
~action of microprocess3r 302 whis~h then ac~l~ates pumps 252
and 278 ~Figure ~ for a pre-determined period o time of 3
fo2 example five seconds causing water t~ be p~7ed through
~3 line5 2S4, 244, line 246 and line ~66 ~o was~e tank 268.
At the same t~me monobath is pumped through lines 280, 274
272, 246 and 266 to drain ~ank 268. The pul~ose of ~hi~
operation is tc) purge air ~ut c~ the liquid supply system.
Next~ mcmelltary ~w~tch 304 is closed causing micro-
15 proce~sor 302 to energl:ze solenc~id 160 to raise plunger 158igure 8) and thus piv~t frame 140 (Fi~ure ~ to raise plate
13~ and ~hen energ~zes m~tor 200 for a peri~d of time ~uf~
ficient to advance film 184 a distance ~lightly greater than
the inner diameter of gasket 126. As soon as motor 200 i~
20 stopped, the microprocessor deenergizes soleno;d 160 causing
spr~ng 166 to move plunger 158 downwardly t~ pivot frame 140
to lower plate 136 onto the film and hold it against gasket
126, the piv~tlng of plate 136 by pins 142 and 144 insuring
that plate 136 will be parallel to gasket 126 and press the
25 film uniformly against the gasket.
After the above described operatiGns ha~e been com
pleted, microprocessor 302 activates pump 252 (Fi~ure 9) and
valve 238 causing water to be pumped int~ ~evelopin~ chamber
210. The circular nature of the chamber and its small depth
30 permitting the surface tension of the liquids employed to
provi~e a capillary type action insuring ~hat even when ~he
apparatus 2 is spatially oriented 0 that the reduced di~meter
pcrtion 216 of ~upply conduit 214 is located at the top of
chamber 210~ the in flowing liquid ~rces ail ~f the fluid
~5 out of the chamber 210. Thus, in all orientations, the
water pumped into chamber 210 thruugh line 244 ~alve 238 line
236 and line 230 forces out all the air ;n cham~er 210 through
~2~
-- ~o --
conduit 218 and lines 290, 294 and 266 to waste container
268. During this operation pump 292 blocks the flow of fluid
therethrough being fluid tight when at rest. When chamber 210
has been filled with water, microprocessor 302 stops pump 2527
deenergizes valve 238 and ceases operation for the time being.
Momentary switch 33~ is now closed to activate timer
switch 330 which immediately activates shutter solenoid 102
to permit the laser beam to be directed by mirrors 64, 66 and
68 (Figure 1) onto coupling 82 and thence reflected througn
opening 122 onto film 184 (Figure 8). The photoelectric cell
350 measures the intensity of the light being reflected to cause
timer 330 to vary the length of time that solenoid 102
energized. After solenoid 102 is deenergized by timerswitch
330 causing spring 100 to close shutter 96 and block off the
laser beam~ coupling 82 is stressed, for example, by pressurizing
the piping system in which pipes 12 and 84 are found. Then
cwitch 334 is again used to activate timer switch 330 to again
expose film 1840
After the shutter closes, momentary switch 304 is
again closed to initiate the developing and fixing of the
film. Microprocessor 302 activates pump 278 and valve 240
(Figure 9) causing monobath 282 to be pumped through lines
280, 274, valve 240 and lines236 and 230 into developing
chamber 210 to displace the water therein which passes through
lines 290, 294 and 266 to waste tank 268. The configuration
of chamber 210 insures the expelling of all of the water from
the chamber. The microprocessor 302 then deactivates pump
278 and valve 240. Normally the developing and fixing time
is about three seconds. Having provided sufficient time for
developing and ~ixing of the film, microprocessor 302 again
activates pump 252 and va~ve 238 to wash the monobath from
chamber 210 and rinse the film with water. Microprocessor
302 then deactivates pump 252 and valve 238.
The thus produced hologram can be viewed by using
3S handle 78 to rotate mirror 68 counter-clockwise as viewed
in Figure 1 to a position toreflect the laser beam from
mirrar 6~ upwardly thrc~u~h fi.Lm 184 wh;le activating, ~he
shutter s~le2l~id :102 lby cl~sillg switch ~sD0 whieh parallels
-_ltimer 330. At ~his ~ta,ge~ if desired, a phc~tograph of the
h~ gram may be ttaken by direoting a camera towards ~plate
136. ~ILnstant cal3era such as are made by Pc)laroid* and Eastm~n
K~dak ~are e~nvenient f~r this purpose.
When it ~:E; desired to make ~c~he nex'L hologram,
~witch 384 ~n micrc~prc)cessor 302 is closed causin~ m;cro~
prc~e~gor to activate pump 2~2 whïch wi~chdraws all :ILiquid
10 f~m ch~m~er ~10 throug~ cc~nduit 218 and line 290 and di~-
charges it ~hrc~ugh line 266 in~o waste cont~iner 268. During
~his speTation air i6 ~uppli:ed to chamber 210 throu~h check
~al~re 234 and ~eTit line 232 and line 230. The apparatu~ i~
now ready to commence a new cycle of operation w~i~h is
15 initiated by closing momentary switch 304 to ad~rance ;1m
184, the purg~ng step caused by clos;ng switch 301 on~y being
used once at the initial ~tart up of ~esting operati~ns and
not necessary when repeated ~ests are being made.
It is evident that the above apparatus can lbe used
20 for real time holography by ~imply develop;r~g ~ilm 184 ater
one exposure and than viewing the film with the laser beam
being reflected from the pipe placf~d under a condition of
stre~s .
The appara~u~ described above can be used withou~
2~ any hou5in~ to keep out light if it is to be used in ~ room
which can 'be darkened. Housing 81 is necessary for th~ ex-
cllasion of outside light when the apparatus is to be employed
ln the field. Housing 81 has a dependîrlg portion 396 with
an open bc~tom opposite ph~tog~raphi.c ~tatlon 86. When em-
30 ployed, hou~.in~ 81 is received in a trou~ 401 ~ecured Soframe 4 and ~ecured thereto by scre~s indicated at 402. A
light excludiTIg shroud 404 comprises black sid~ cloths 406
and 408 and end ~lack cloths 410 and 412. Each of the cl oths
406 and 408, 410 and 412 has its uppper end adhesively secured5 to depending p~rtion 396 of housing 8i~ As illustrated in
e 14, the side clt~ths 406 and 408 are wr~pped around
pipes 12 and 84 ~nd ~oupling 82 and held together by a strip
* Trademark
of ~dhesive tape i.ndicated at 414. The end cloths 410 and
412 are draped t)ver pipes ~4 and 12, respective.ly and ~athered
against eloLn~ 4ub and 408 lto bl~ck the entry of light through
th end~ of the shroud. Such ~ ~hrc)ud i6 conventional as seel-
~ v.~. ~.
5 from~1 Patent ~,171,914.
H~usmg 81 ha~ a :Ligh~-tight ccver 420 piv~tally
cDnneeted ~o ht~using 81 ~t 422 and covering opening 424 which
w~eD c~ver 42 0 is open permits sriewing of the phc~tc?,grap~ic
~tati~n 86. A handle 4~8 is attached to hc~using 81 to facil-
10 itate earrying the apparatus.
As di~cussed ~bc~ie the cont~ur o ~he periphery ~f~he de~elDpî~ng c:h~m6er always c~nges direction ~t an angle of
greater than 125~. This permits numert~us differerlt configura
ti~ns . - -
In F~gure 15 there is an alterrlative transparent
plate 12DA which is i:denticaï to plate 120 having a supply
conduit 214A and a discharge cs:~nduit 216~ but has an elliptica]
grDove 124A containing a gasket 1~6A.
An alternati~re transparent plate 120B ~Figure I6) is
20 ideIItical t~ pla~ce 120 having a supply ec>nduit 214B and a dis-
charge conduit 218B but has a decagonal groove 124B and a gaskE
126B thereirl.
An alternative transparent plate 120C (Figure 17)
is identical to plate 120 and has a supply c~ndui~c 214C and a
25 discharge conduit 218C but has a gr~ove 124C having straight
sides! 450 and 452 and curved portions 454 and 456. A gasket
126C is in gro~ve 124C.
All of the plates 120A, 12DB and 120C with their
associated gaskets will form df~veloping chambers with plate 13
30 havin~ peripheries with suitable c~ntours.
It will be underst~od that the above described appar-
atus i~ illustrative and is not intended to be limiting.
.
