Port section structure for mounting replacements on a shielding box

An improved structure of a section for mounting a replacement such as a filter, glove, bag or the like on a wall of a shielding box in which a material such as a radioactive or other hazardous material or the like, and/or an apparatus impossible of direct contact with a hand are disposed. The mounting section comprises a cylindrical fixed port secured to the wall, and a cylindrical replacement port having the replacement and adapted to be fitted into the fixed port. A plurality of rubber or the like elastic rings spaced from each other in an axial direction are sealingly disposed in a compressively deformed state between the two ports. Thus, renewal can be achieved by pushing out a spent replacement port with another, as needed.

TECHNICAL FIELD 
The present invention relates to a structure of a port section for mounting 
a replacement such as a filter, glove, bag or the like on the wall of a 
box for shielding the dangerous atmosphere in which an indirectly handled 
radioactive or other hazardous material and/or an indirectly manipulated 
apparatus are present. In order to safely carry out renewal of the 
replacement without the conventional large-sized, complicated replacer, a 
plurality of elastic rings are disposed between a fixed port and a 
replacement port. The renewal can be easily achieved only by applying a 
pushing force to the replacement port in an axial direction thereof. 
BACKGROUND ART 
When a radioactive or other hazardous material is handled, or a certain 
apparatus is manipulated in a hazardous atmosphere containing such 
material, such a material and/or apparatus must be placed in a shielding 
box and must be indirectly handled or manipulated from the outside of the 
box. 
As shown in FIG. 1, this shielding box 1 is made of a transparent material 
for observing the state of things within the box. The shielding box 1 is 
provided with gloves 3 and bags 4 on its side wall 2, and has an air 
supply filter 5a and exhaust filters 5b on its lower and upper walls, 
respectively. The gloves 3 are used for indirectly handling the 
radioactive material or for manipulating the apparatus by the operator's 
hands. The bags 4 are employed for removing spent articles from or for 
inserting necessary articles into the box 1. The air supply filter 5a is 
used for introducing fresh air into the shielding box 1. One of the 
exhaust filters 5b is employed for cleaning the polluted air and for 
discharging the cleaned air out of the box 1, and it is connected to the 
shielding box 1 at one end thereof and to an exhaust duct 7 at the other 
end thereof, each such connection being through a connecting pipe 6b 
having a polyvinyl chloride tube 6a. 
FIG. 2 shows a conventional port section for replacing an old glove with a 
new one which is one of the replacements in the shielding box 1 described 
above. As shown in FIG. 2, a fixed port 21 having an opening 21a 
communicated with the outside in its central portion is secured to the 
side wall 2 of the box 1 through an U-shaped packing 24, by a ring-shaped, 
plate member 23 adapted to be tightened by a bolt 22. Into the opening 21a 
of the fixed port 21 is sealingly fitted a port to be replaced or 
replacement port 25. The fixed port 21 having a threaded portion 26 on its 
inner periphery is threadingly engaged with a glove replacement port 25 by 
compressively deforming an elastic screw member 27 adhered to the outer 
periphery of a larger cylindrical part 25a of the port 25 which will be 
hereinafter described. The replacement port 25 comprises two cylindrical 
parts 25a and 25b, the former being larger than the latter in diameter. 
The larger cylindrical part 25a of the replacement port 25 is provided 
with a pin 29 on its rear end surface and a hole corresponding to the pin 
29 on the front end surface thereof. Over the smaller diameter cylindrical 
part 25b is tightly mounted a base 3a of the glove 3 by means of sealing 
band 30 and an O-ring 31. In back of this replacement port 25, another new 
glove replacement port 25 having the same construction as the former port 
is standing ready in a situation that a new glove 3 is sealingly fixed to 
the latter port 25 (the same reference numerals designate an identical 
part, so that the repeated description thereof is omitted). 
In operation of replacing the old glove 3 with a new one, first the old 
replacement port 25 screwed into the fixed port 21 is brought into contact 
with the new replacement port 25 having a new glove 3 by inserting the pin 
29 into a hole 28 of the latter port 25 for combining the two ports 25. 
Then, the combined replacement ports 25 are simultaneously pushed forward 
while subjecting to a rotational torque by an extruder (not shown) 
arranged behind the new replacement port 25. Therefore, when the new 
replacement port 25 reaches a predetermined position, the old replacement 
port 25 is automatically dropped into the shielding box 1, thereby 
achieving renewal of the port 25, and hence glove 3. 
FIGS. 3 and 4 show the constructions in which a replacement bag 4 and a 
replacement filter 5 are sealingly fixed to the replacement port 25 
elastically screwed into the fixed port 21, respectively. In these 
examples, renewals of the bag 4 and the filter 5 are carried out in a 
manner similar to that of replacement of the glove as shown in FIG. 2. 
The structure of the replacement port section in the shielding box 1 
described above is disclosed, for example, in U.S. Pat. No. 4,156,146 and 
Japanese Patent Disclosure No. 149597/77. 
However, according to the structure of the replacement port section of the 
conventional shielding port 1, for the purpose of renewal of the 
replacement such as the glove, bag or filter fixed to the replacement port 
25, a great rotational torque must be applied to the replacement port 25 
by means of a large-sized, complicated extruder because of the very tight 
engagement of the fixed port 25 with the replacement port 21 through the 
threaded portion 26 and the elastic screw member 27. 
In view of the above-mentioned features, the present invention provides an 
improved structure of a port section for mounting a replacement on the 
shielding box. According to this structure, a plurality of elastic rings 
in a compressively deformed state are arranged between a fixed port and a 
replacement can be safely carried out only by applying a pushing force to 
the replacement port in an axial direction thereof, without applying a 
rotational torque to the port. 
SUMMARY OF THE INVENTION 
That is, the structure of a port section for mounting a replacement on the 
wall of a shielding box according to the present invention comprises: 
a fixed port sealingly secured to the wall of the shielding box and having 
an opening communicating with the interior of the shielding box; 
a replacement port disposed with the opening; 
a replacement secured to the replacement port; and 
a plurality of elastic rings spaced from each other in an axial direction 
thereof and adapted to be disposed in a compressively deformed state 
between both ports for sealingly supporting the replacement port within 
said opening, thereby enabling renewal of the replacement secured to the 
replacement port only by applying an pushing force to the replacement port 
in an axial direction thereof.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings, the preferred embodiments of the present 
invention will be described below. FIG. 5 shows a replacement port section 
for the supply filter provided on a side wall 2 of a shielding box 1 in 
accordance with the present invention. A fixed port 21 has an opening 21a 
through which the shielding box 1 communicates with the outside thereof, 
and of which a smooth inner periphery constitutes a part of the fixed port 
21. The fixed port 21 is secured to the wall 2 of the box 1 by means of a 
circular section of ring packing 24, bolts 22 and a fixing member 23. 
Alternatively, the fixed port 21 may be formed integrally with the wall 2. 
Likewise, the fixed port 21 may be secured to the wall 2 through a 
U-shaped section of ring packing instead of the circular section of the 
packing 24. A cylindrical air supply filter replacement port 25 having a 
filter 5 therein is fitted into the inner periphery of the fixed port 21 
through an elastic member 27. Replacement port 25 comprises a rigid filter 
ring. A cylindrical replacement filter 5 comprising wound glass fiber 
fabrics is fixedly adhered to the inner wall of the replacement port 25. 
On the uniform outer periphery of the filter replacement port 25 is 
fixedly adhered cylindrical elastic member 27 made of polychloroprene 
rubber and having three spaced, ring-shaped projections 27a in its outer 
surface with epoxy or silicone rubber adhesives. The compressive 
deformation of the ring-shaped projections 27a provides a seal between the 
fixed port 21 and the filter replacement 25. Therefore, the outside 
diameter of the ring-shaped projections 27a is, of course, larger than the 
inside diameter of the fixed port 21. 
In this case, the structure of the filter replacement port 25 is 
ring-shaped so as to prevent deformation of the filter 5 per se. However, 
if the filter 5 itself can prevent deformation, it may form the filter 
replacement port 25. The filter replacement port 25 is made of 
thermosetting resin, e.g. phenol resin, because it has good adhesiveness 
to polychloroprene rubber. However, the port 25 may be made of metallic 
material and, in particular, it is preferable to select such a material 
capable of minimizing and lightening waste matters thereof. Reference 
numeral 29 designates a pin provided on the outer periphery of the fixed 
port 21. 
In operation of renewal of the filter 5 thus constructed at the replacement 
port 25 in the case of using an extruder or extruder type replacer 44 
comprising a pin hole 28, a cylindrical portion 40, a disk 41, a reduction 
gear 42 and a handle 43, as shown in FIG. 6, first each pin 29 is fitted 
into the hole 28 to fix the extruder 44, then a new filter replacement 
port 25 pre-positioned within the cylindrical portion 40 and having the 
same structure as that of the old port 25 described above is moved forward 
to make the front face of the former port 25 contact with the rear face of 
the latter port 25 by rotating the handle 43 and advancing the disk 41. 
The handle 43 is rotated until the old port 25 is forced out of the fixed 
port 21 and falls into the shielding box 1 and the new port 25 is fixed to 
the inner periphery of the fixed port 21. Thus, the replacement or renewal 
of the filter port 25, and hence the filter 5 is completed. 
During this replacement operation, the sealing between the fixed port 21 
and the filter replacement port 25 is maintained perfect by the 
compressive deformation of the ring-shaped projections 27a. Therefore, the 
shielded materials will never leak out. 
In this case, according to the frictional resistance between the 
ring-shaped projections 27a and the fixed port 21, it is preferred to coat 
the surface of the projections 27a with lubricant such as grease or the 
like. The use of the extruder type replacer 44 provides an advantage that 
an operator can carry out the renewal operation without direct contact 
with the filter replacement port 25. The cylindrical portion 40 of the 
extruder 44 has an eyehole 40a to confirm the normal movement of the 
filter replacement port 25. 
FIG. 7 shows another embodiment of the present invention wherein a 
replacement port section for an exhaust filter is mounted on the upper 
wall of the shielding box 1, a cylindrical fixed port 21 is provided in 
the exterior of the shielding box 1, and the filter replacement port 25 
communicates with the interior of the box 1 through an exhaust duct 45 
which forms a part of the fixed port 21. The fixed port 21 can accommodate 
plural filter replacement ports 25, one of which is disposed therein as a 
spare as shown on the right in FIG. 7. In the front end of the filter 
replacement port 25 are formed an appropriate number of slits 25c. In one 
end of the fixed port 21 is provided a pressure control damper 46 to 
maintain the negative pressure within the shielding box 1 constant. This 
damper 46 is secured to a cover 48 mounted on the fixed port 21 along with 
a filter 47. The gas stream purified by the filter 5 positioned in the 
port 25 is discharged from an exhaust duct 49 connected to the fixed port 
21 through the slits 25c. 
Renewal of the exhaust filter replacement port 25 is carried out in a 
manner similar to that in the embodiment of FIG. 6, but in this case the 
spent filter replacement port 25 pushed out is removed by a bag 50, a 
protective cover 51, a movable filter receiving device 52, which are 
provided in the opposite end of the fixed port 21. Accordingly, there is 
no necessity for cutting and removing the vinyl tubes connected to both 
ends of the filter case during each renewal of the filter, as in the 
conventional method. 
Further, reference numeral 53 designates a bag receiver or supporter 
removably provided on the end face of the replacement port 25 for 
preventing the drop in filtering capacity of the filter 5 due to suction 
of the bag 50. 
FIG. 8 shows still another preferred embodiment of the present invention 
wherein an exhaust filter replacement port 25 is provided in the side wall 
2 of the shielding box 1. More particularly, a fixed port 21 has a 
construction similar to that shown in FIG. 5, but in this case the 
polluted air stream is directly sent from an opening 21a of the fixed port 
21 through the filter replacement port 25 to an exhaust duct 49. 
According to this construction, the spent filter replacement port 25 can be 
easily removed only by dropping it into the shielding box 1. Therefore, 
there is no necessity for using the bag 50, protective cover 51, filter 
receiver 52, as shown in FIG. 7. 
FIG. 9 illustrates another embodiment of the present invention wherein the 
main replacement members for the filter replacement port 25 are applied to 
a glove 3 and, in particular, a glove replacement port 25 is used instead 
of the air supply or exhaust filter replacement port 25 described above. 
As shown in FIG. 9, the glove replacement port 25 in the replacement port 
section comprises a cylinder having two cylindrical parts 25a and 25b 
different in diameter. To the outer periphery of the cylindrical part 25a 
is, in a manner similar to that of the glove described above, adhered a 
cylindrical elastic member 27 having ring-shaped projections 27a formed on 
the outer surface thereof. Over the outer periphery of the cylindrical 
part 25b smaller in diameter than the part 25a, is fixedly mounted the 
base 3a of the glove 3 by means of a ring-shaped tightening band 30, and 
O-ring 31. Renewal of the glove 3 in this case can be easily carried out 
by preparing a new glove replacement port 25 having the same construction 
as the old one, as shown on the right of FIG. 9, and utilizing the 
extruder type replacer (not shown). Accordingly, there is no necessity for 
using the bag utilized in the conventional method, and there is no danger 
that the polluted materials might leak out from the base 3a of the glove 
3. 
FIG. 10 illustrates still another preferred embodiment of the present 
invention wherein instead of the glove 3 described above, a bag 4 is 
provided on the replacement port 25 having the same construction as that 
of FIG. 9. The filter or glove replacement port 25 or the like dropped 
into the shielding box 1 can be easily and safely removed from the box 1. 
In addition to a replacement such as the glove 3 or filter 5 described 
above, there is a cap adapted to be provided in a position of very low 
frequency of use for sealing the shielding box 1 from the outisde. To this 
cap may be advantageously applied the replacement port 25 described above 
as a cap replacement port. 
In the preferred embodiments of the present invention described above, a 
semi-circular section of ring-shaped projections are formed on the outer 
surface of a rubber body and such rubber body is fixedly adhered to the 
outer periphery of the filter, glove or bag replacement port. However, as 
shown in FIG. 11(a), ring-shaped projections 27b of triangular section may 
be formed alternatively with the ring-shaped projections 27a of 
semi-circular section on the outer surface of the rubber body 7 on the 
filter replacement port 25. Thus, even if the inner periphery of the fixed 
port has damaged portions, they may be filled up with the tops of the 
triangular projections, thereby improving the sealing performance. 
Furthermore, as shown in FIGS. 11(b)-(d), a plurality of ring-shaped 
grooves 25d and/or 21b may be formed on the outer periphery of the filter 
replacement port 25 and/or the inner periphery of the fixed port 21, 
respectively, and in each of the grooves 25d and 21b may be positioned an 
elastic ring 27a or 27c in the place of the ring-shaped projections 
described above. Thus, this construction can eliminate the cylindrical 
rubber portion and hence, is economical. In these embodiments, the 
semi-circular, triangular, or square section of ring-shaped projections 
have been indicated, but the present invention is not intended to be 
limited to such sectional shape. 
As described above, renewal of the replacements such as the filter, glove, 
or bag can be efficiently, surely and safely carried out only by pushing 
the new replacement port into the shielding box due to the simple 
construction thereof according to the present invention. During this 
renewal operation, the sealing performance between both ports can be 
maintained perfect owing to the compressively deformed state of the 
ring-shaped projections. In addition, there is no necessity for screwing 
the replacement port into the shielding box, as in a conventional manner, 
and hence no rotational torque is required to screw the replacement port 
therein. Thus, the present invention is of great industrial value. 
As described above, the structure of the port section for mounting a 
replacement such as a filter, glove, bag or the like on the shielding box 
according to the present invention can safely and easily carry out renewal 
of the replacement when such a replacement becomes unserviceable. 
Therefore, it is very advantageous to utilize the structure of the present 
invention with a box or container in which various materials to be 
shielded are arranged and which such materials must be handled or 
manipulated from the outside thereof.