close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3083307

код для вставки
United States Patent 0 Cs
3,033,297
Patented Mar. 26, 1963
1
2
METHOD OF DETECTING FLAWS 1N ARTICLES
William Claud Lockwood, East Kiihride, Lanarkshire,
Scotland, assignor to Rolls-Royce Limited, Derby, Eng
land, a company of Great Britain
lilo Drawing. Filed Jan. 8, 1969, Ser. No. 1,172
Claims priority, application Great Britain Feb. 18, 1959
12 Claims. (Cl. 250—71)
of at least 30 seconds and preferably of 2—5 minutes, so
as to ensure that the penetrant enters all the ?aws in the
article, after which surplus penetrant is drained from the
article for a period of at least 30 seconds and preferably
of 2-5 minutes.
The penetrant is then removed from any surface to be
tested in such a way that the penetrant will remain in the
?aws and in the said surface but will be completely re
moved from the un?awed parts thereof. This is effected
This invention concerns an improved method of de 10 partly by means of a washing operation but mainly by
tecting ?aws in articles.
According to the present invention there is provided
a method of detecting ?aws (e.g. cracks) in a liquid
impermeable surface of a body comprising applying to
means of employing ?nely divided particulate material.
The said washing operation may consist of hosing the
blade with lukewarm water e.g. at 30-45” C. This water
must not contain a wetting agent or a detergent. The
= said surface a liquid penetrant so that the latter pene 15 Washing operation should only be of suf?cient duration
- trates into the said ?aws; employing ?nely divided par
to remove the obvious liquid penetrant ?lm on the sur
ticulate material to remove the penetrant completely
face of the blade.
from the un?awed parts of said surface While leaving the
penetrant in said flaws and while leaving said surface sub—
In order to facilitate subsequent handling, the blade is
then dried in a stream of air.
Complete drying of the
stantially unimpaired in quality and dimensions; and 20 blade is, however, unnecessary.
The removal of the surplus penetrant by the ?nely di
1riendering visible the penetrant which has been left in the
aws.
vided particulate material may be effected either by blow
The ?nely divided particulate material may comprise
ing the material onto the blade or by tumbling the blade
powdered fruit stones (e.g. powdered plum stones) or
in the material.
powdered nut shells (e.g. powdered walnut shells).
In the former case, the blade is transferred to a blast
25
The penetrant may be removed from the unilawed parts
cabinet where all the surfaces of the blade are blasted
of the surface by blowing the particulate material onto
with ?nely divided plum stones of grit size No‘. 3. The
said surface.
blast pressure within the cabinet is maintained at between
Alternatively, the penetrant may be removed from the
5 and 10 pounds per square inch, the pressure chamber
unliawed parts of said surface by tumbling the body in a 30 and circulating system of the blast cabinet being such
water-saturated aggregate comprising ?nely-divided par
that, during blasting at least 100 pounds of the ?nely di
ticulate material.
vided plum stones is in circulation. Ultra violet light is
The said aggregate may comprise tumbling chips.
provided within the blast cabinet, blasting being carried
Thus the aggregate may comprise substantially 50% by
out for a length of time just su?icient to remove back
weight of ?nely divided plum stones and 50% by weight 35 ground ?uorescence from the blade. Dust is continu
of granite or aloxite tumbling chips.
ously removed from the blast cabinet since the presence
Preferably the penetrant is rendered visible by apply
of excessive dust may prevent ?ne surface defects in the
ing to said surface a powder which is adapted to absorb
blade from showing up.
or adsorb the penetrant.
Alternatively, if the surplus penetrant is removed by
The penetrant may be'a ?uorescent substance or may 40 tumbling, the tumbling operation may comprise tumbling
be coloured with a ?uorescent dye, the penetrant left in
the blade in a tumbling machine for a period of 30-40
the flaws being detected by viewing said surface under
minutes, the tumbling machine containing a Water satu
ultra-violet light.
rated aggregate. This aggregate is formed by adding clean
Alternatively the penetrant may be non-?uorescent and
cold water to a mass consisting of 50% ‘by weight of
have a colour which is readily distinguishable from that 45 ?nely divided plum stones (e.g. British Standard Mesh
of the surface of said body. Thus the penetrant may con—
size 12) and 50% by weight of granite or aloxite tumbling
tain a non-‘luorescent dye (e.g. a simple red dye).
chips. The water is added to the said mass until the ag
The removal of the surplus penetrant may be partially
gregate so formed is saturated and any excess water is
effected by washing said surface prior to the treatment
run off. Tumbling thus takes place in a kind of mud or
with the ?nely divided particulate material.
50 slurry.
Any ?nely divided particulate material adhering to the
After the blasting or tumbling operation, any ?nely
said surface after the said treatment may, if desired, be
divided particulate material or aggregate adhering to the
removed prior to the rendering visible of the penetrant
which has been left in the ?aws.
'
The invention will now be described, merely by way
of example, with reference to its application to the detec~
blade is removed by blowing air onto the blade or by a
cold water wash, after which the blade is dipped in hot
water and is dried.
The blasting or tumbling operation is ‘carried out in
such a way and the ?nely divided particulate material
If the blade has any surface contamination (e.g. grease
or aggregate employed is such that the surfaces of the
i or till) this is ?rst removed, e.g. by employing trichlor
blade are not pitted or otherwise damaged whilst at the
ethylene vapour at 87° to 120° C.
60 same time substantially no material is removed from them.
The blade is then submerged in a ?uorescent liquid
_The blade is then submerged for a period of 5—l0 min
penetrant which is adapted to penetrate into the cracks
utes in a powder which is adapted to absorb or adsorb
and other flaws in the surface of the blade. If the blade
the liquid penetrant. This powder (hereinafter for con
has been treated with the hot trichlorethylene vapour it
venience referred to as “developer powder”) may consist
will of course have become heated itself. It may never
tion of ?aws in a compressor rotor blade.
theless be immersed, Without prior cooling, in the pene—
trant provided the temperature of the penetrant is not
raised thereby above 30° C.
65 of or comprise silica or talc.
Surplus developer powder is then removed by blowing
dry compressed air, at a pressure not exceeding 25 lbs.
The ?uorescent liquid penetrant employed may, for eX
per square inch, onto the blade or, alternatively, by
ample, be any of those marketed under the trade names 70 knocking the surplus developer powder olf. For a period
Zyglo Pentrex, Zyglo Super Pentrex, and Britemore.
of at least 5 minutes and preferably of 20 minutes the
The blade is submerged in ‘the penetrant for a period
blade is allowed to stand so that the developer powder
3,083,297
4
3
?nely divided plum stones and 50% by weight of tum
bling chips formed from materials selected from-the group
comprising granite and aloxite.
is allowed to adsorb or absorb the liquid penetrant so as
to indicate clearly the portions of the blade surfaces con
taining the flaws.
8. A method of detecting ?aws in a liquid-impermeable
The blade-is then viewed under ultra-violet light in a
dark room, when the positions of the penetrant-soaked 5 surface of a body comprising applying to said surface a
liquid penetrantv to cause the latter to penetrate into the
developer powder will indicate the positions of the flaws.
said ?aws; employing ?nely divided particulate organic
The present invention, in providing for the removal .
mate-rial to remove ‘the penetran-t completely from the
of the surplus penetrant by ?nely divided particulate
material, obviates the need to use expensive chemicals ,
for this purpose.
Iclaim:
un?awed parts of said surface while leaving the pene
10 trant in said flaws and while leaving said surface substan
tially unimpaired in quality and dimensions; and apply
'
ing to said surface a penetrant-absorbent powder which
1. A method of detecting flaws in a liquid-impermeable
renders visible the penetrant which has been left in the
?aws.
comprising applying to said surface ‘a liquid penetrant to
9. A method of detecting flaws in a liquid-impermeable
cause the latter to penetrate into the said ?aws; employing 15
surface of a body comprising applying to said surface a
finely, divided‘ particulaterorganic material to remove the
?uorescent liquid penetrant to cause the latter to pene
penetrant completely from the unilawed parts of said sur
surface of a body having a~high quality surface ?nish
tt-rate into the said‘ ?aws; employing ?nely divided par
face while leaving the penetrant in said flaws and while
leaving said surface substantially unimpaired in quality
ticulate organic material to remove the pen'etrant com
liquid penetrant to cause the latter to penetrate into the 2
said'?aws; employing powdered fruit stones to remove the.
penetrant completely from-the un?awed parts of said sur
10. A method of detecting ?aws-lin- a liquid-impermea
ble surface of a body comprising applying to said sur
face a liquid penetrant to cause the'latter to penetrate into
pletely from the unil'lawed parts of said surface while
and dimensions; and rendering visible the penetrant which 2 O leaving the penetrant in said'?aws andwhile leaving said
has been left in the flaws.
surface substantially unimpaired in quality and dimen
2. A method‘ of detecting‘ ?aws in a liquid-impermeable
sions; and employing ultra-violet light to render visible
surface of a body comprising ‘applying to said surface a
the penetrant which has been left in the ?aws.
face while leaving the penetrant in said ?aws and while
the said ?aws, the colour of said penetrant being readily
leaving said surface substantially unimpaired in quality
and dimensions; and rendering visible the penetrant which
distinguishable from that of the surface of the body; em
3O
has been left in the ?aws.
3. A method'of detecting flaws in a liquid-impermeable
surface of a body comprising applying to said surface a
liquid penetrant to cause the latter to penetrate into the
said ?aws; employing powdered nut shells to remove the
penetrant completely from the un?awed parts of said sur 35
face while leaving the penetr-ant in said ?aws and while
ploying ?nely divided particulate organic material to re
move the penetrant completely from the un?awed parts
of said surface while leaving the penetran't in said ?aws
and while leaving said surface substantially unimpaired
in quality and dimensions;iand rendering visible the pene
trant which has been left in the flaws.
lil. A method as claimed in claim 10 in which the
penetrant contains a non-?uorescent dye.
leaving said surface substantially unimpaired in quality
12.. A method of detecting ?aws in a liquid-impermea
and dimensions; and rendering visible the penetrant which
ble surface of a body comprising applying to said‘ sur
has been left in the ?aws.
face a liquid penetran-t to cause the latter to penetrate
4. A' method of deteeting'?aws in a liquid-impermeable 4O into the said' ?aws; washing said surface and thereafter
surface of a body comprising applying’ to said surface a
employing ?nely divided dry particulate organic material
liquid‘ penetrant to‘ cause the latter to penetrate'into the
to remove the penetrant completely from the un?awed'
said flaws; blowing and circulating ?nely divided dry
parts ‘of said surface while leaving the penetrant in said
flaws and while leaving said surface substantially uni-In
paired in quality and’ dimensions; and rendering visible
particulate organic material on to said surface to remove
the penetrant‘ completely from the un?awed parts of said
surface while leavingthe penetrant in said ?aws and while
leaving said‘ surface substantially unimpaired in quality
and. dimensions; continuously removing dust from said
material duringiitsa circulationyand rendering visible the
penetranttwhich' has been leftiin the flaws.
5. A method‘ of detecting flaws in a liquid-impermeable
surface of a body, comprising applying to said, surface
the penetrant which has been left in the flaws.
References Cited in the ?le of this patent
50
a liquid penetrant to cause the latter to penetrate into the
said-?aws; tumbling the body in a water-saturated aggre 55
gate comprising t?nely divided‘ particulate material to re
move thepenetrant‘completely from the unllawed parts of
said surface whilesleaving' the'penetra-nt in said flaws; and
rendering visible the penetrant which has been left in the
UNITED STATES PATENTS
1,750,499
Truax ______________ __ Mar. 11, 1930
2,470,341
2,478,951
2,622,047
2,707,236
Darrahv _______ ________ May 17,
Stokely et al ________ _____ Aug. 16,
Ayers ______________ __ Dec. 16,
De Forest ___________ __ Apr. 26,
1949
1949
1952
1955
OTHER REFERENCES
Catlin: Fluorescent Method Detects Leaks in Process
'
i
Vessels, Chemical and Metallurgical Engineering, \August
6. A. method as claimed in claim 5 in which said ag 60
?aws.-
gregate comprises tumbling chips.
7. A method as claimed in claim 5 in which said
aggregate comprises- substantially 50% by weight of
1943, page 1176.
Ellis: Fluorescent Penetrant Inspection, Steel, Oct. 16,
1944, pp. 100-102.
'
Документ
Категория
Без категории
Просмотров
0
Размер файла
354 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа