Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~5255
The invent~on relates to an apparatus ~or gamma
irrad~ation treatment of temperature-sensitive material, the
apparatus being of the type w~ere~n gamma-radiation source
mater~al is d~sposed ~n a radiat~on source frame mova~le from a
screened position into an operative posit~on.
b` It has been found that in high-power irradiation
plants the irradiated material or the package heats up considera-
bly, due to the absor~ed rad~ation be~ng converted into heat,
which may result in damage to the material. Much of the heat is
evolved in the sources th~mselves and in their cladding. The
- rad~ation source fr~me therefore acts as heating means.
- It is an ob~ect of the invention to provide an
apparatus of the a~ove type wherein the material for irradiation
is not overheated as the heat generated ~y the radiation source
frame to the material is reduced. According to the invention,
therefore, the rad~ation source frame has passages for the dis- ;-~
tri~ut~on of a fluid coolant, the passages having at least one
connection through which they are arranged to communicate with
`~ a coolant supply system, during the operation of the device.
j 20 In gener~l terms, the present invention proviaes
an apparatus for gamma irradiation treatment of temperature-
sensitive material, of the type wherein gamma-radiation source
~ is disposed in a radiation source supporting frame movable from
J a screened position into an operative position, wherein the
s radiation source supporting frame has coolant passages ~or
the distribution of a fluid coolant, the passages having
at least one connection through which they communicate with
a coolant supply system when the frame is in said operative
~ position.
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~U4S255
In cases in wh~ch the radiation source frame is
arranged to be i~mersed into a water pool for screening, the
coolant passages arè formed with at least one discharge orifice,
and provided with stationary means for closing such orifice upon
the radiation source frame having reached ;ts operative position.
In cases in which the radiation source frame has
` tubes for receiving the source material, the coolant passages
can ~e connected to such tubes. In this event the tubes for the
source material can have internal centering ribs for supporting
'10 the source material. -
,.,
The coolant can discharge into the surroundl~ngs of
the radiation source frame and a suction device can ~e disposed
'~ i`n the reg~on where t~e coolant discharges.
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1045Z55
The suct~on device can Be of a s~ze and design
suita~le for ~andling a quantity of coolant in excess of that
supplied to the radiation source frame.
Aavantageously, t~e source mater~al pieces are
surrounded By a screen for guiding t~e coolant along t~e respec-
tive piece.
If the coolant is water, a condenser may be inter-
posed ~n the water feed line for prec;pitating atmospher;c
' humidity on such condenser.
Some em~od~ments of the sub~ect of the invention
(: ~
will Be descriBed hereinafter with reference to the drawings
;! wherein:
Fig. 1 is a view in side elevation of a radiat~on
source frame according to the invention in ;ts operative pos~tion;
Fig. 2 is section II-II of Fig. l;
~ig. 3 is a vertical section on the line III-III
t of T~g. l; ~ -
Fig. 4 s~ows a water-cooled radiation source frame
according to the invention;
Fig. 5 is an elevation of a modif~ed form of the
frame shown ~n Figs. 1 and 2; and
Fig. 6 is section ~I-VI of Fig. 5.
~ounted for vertical movement Between two vertical
channel-section mem~ers 1 with their open sides facing one another
is a rectangular frame 2 welded together from rectangular ~ox
section Bars and having a top mem~er 3, a Bottom memBer 4, a
left~hand side mem~er 5 and a right-hand side mem~er 6. Frame 2
i~s carried on two steel ca~les 10 which are secured to eyes 11
welded to the top mem~er 3 and which run over two pulleys 12.
3~ Extending ~etween the top member 3 and ~ottom mem~er 4 of frame
2 is a lattice consisting of twelve vertical sleeves 20 which
are welded to the bottom member 4 and which extend through t~e
10~5~55
top member 3. The sleeves 20 are open at the top and
closed at the bottom. The bottom member 4, supporting
the sleeves 20, is formed with passages 21 for
compressed air which is distributed as a coolant within
the sectional shape of the mem~ers 3 to 6. The compressed air
enters the ~ox sect~on mem~ers t~rough two spigot~ 30. When the
radiation source frame is in its operative position, the spigots
3Q extend into funnels 31 of two supply lines 32. The frame
~ottom member 4 is ~ormed near each end wit~ a passage 35 which,
when the frame is in the operative position, is closed by an
L-shaped spring 36 secured to the channel-section mem~ers.
Disposed a~ove the radiation source frame is a suction header
40 through which the heated cooling air and am~ient air is drawn
away through apertures 41 and thus removed from the treatment
cham~er. The suction duct 40 is of a size and design to handle
a larger volume of air than the volume of cooling air supplied
to the radiation source frame, thus ensuring satisfactory ven-
ti~lation of the treatment room.
In operation, the sleeves 20 are charged with rod-
like radiation sources. Cooling air is supplied through the lines32 and spigots 30 into the frame 2, passes through the passages
;; 21 from the ~ottom of the sleeves 20, rises to cool the same and
i9 remoYed through the duct 40. To take the plant out of
operation, the radiation source frame is lowered ~y means of the
ropes 10 into a water pool 45 in which the cooling effect is pro-
vided ~y heat transfer to the water. To start the plant, the
- radiation source frame is raised up, water 2 which is present
in the frame 2 discharging through the orifices 35. As the
radiation source frame is raised into its operativé position,
the springs 36 close the orifices 35 and communication i~ e~-
ta~lished with the air supply lines 32.
In the em~odiment shown in ~ig. 4, the radiation
sources are cooled ~y water even when the apparatus ~s in its
operat~Ye position. To aYoid the undesired increase in atmospheri~c
- 3 _
lV4525S
humidity in the irradiat~on cham~er, the cooling water is cir-
culated only within the radiation source frame.
The water rises from the ~ottom memBer 4 of the
frame 2 through passages 50 into annular spaces, ~ounded by
radial ribs 52, between the sleeves 20 and the radiation sources
35 received therein, the hot water being collected in the box
section member of the top member 3 of the frame 2, whereafter
the heated cooling water descends in the frame side member 6 and
discharges through a bend 60 into a pocket 61 to which a dis-
10 charge line 62 is connected. A feedwater line 65 has cooling
- ri~s or fins 66 to act as a condenser. Atmospheric humidity can
~e separated from air on the ribs 66. The condensate drips into
a channel 68 secured to the channel-section Bars and flows
~; through a connecting pipe 69 into pocket 61. To ensure a uniform
flow through the sleeves 20 despite a slight inclination of the
~ radiation source frame, the top end of the sleeves 20 is formed
r` with ~saaped notches 70.
~igs. 5 and 6 are an elevation and plan view and
horizontal section, respectively, through slightly modified form
20 of the source radiation frame shown in Pigs. 1 and 2. For improved
` cooling air guidance and to reduce heat radiation from the hot
} sleeyes 20 to the material to Be irradiated, a thin metal shield
8Q i~s-placed around the sleeves 20. The sh~eld 80 is made of two
originally flat sheet~metal memBers which are Bent into a corru-
gated shape such that when assemBled they are at a su~stantially
constant distance from the surface of the sleeves 20. The sheet-
metal memBers are weided By one longitudinal seam each at 81 and
82. The sheet.metal memBers are wider than the internal he~ght
of the frame 2 and are each formed with two recesses 83, 84
30 receiving the mem~ers 3 and 4 of the frame 2. The sheet-metal
memBers are then spot-welded at places 85 to the memBers 3 and 4
of frame 2. Seg~ental gaps 8~ re~ain ~etween the mem~ers 3, 4
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- ~0452SS
: and the shield 80. ~eated cooling air flows through same to the
top, thus creating t~e e~ector effect resulting in am~ient air
~eing drawn in through ~ottom ends of the gaps 86.
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