Filter element

A plurality of filter elements which are located in waste containers is disclosed. The filter elements serve for the precipitation of materials which are injurious to health from air streams, and in particular, from air streams in the field of nuclear installations and the disposal of said materials.

BACKGROUND OF THE INVENTION 
I. Field of the Invention 
The present invention is concerned with filter elements in housings which 
are equipped with exchange devices. The present invention is also 
concerned with contamination protection and a method for the precipitation 
of materials which are injurious to health from the breathing air or 
processing air. The present invention is especially for ventilating 
systems wherein the process is connected with the process for comminution 
and removal of contaminated filter elements for the purpose of long-term 
storage in preferably subterranean deposits utilizing special waste 
containers, which waste containers are constructed in a round or angular 
shape. 
II. Description of the Prior Art 
In the case of such filter elements which are enriched or saturated with 
dangerous materials, it is customery, due to the extraordinary long-term 
effect, either to burn these filter elements at very high temperatures and 
turn them into ash or to put these filter elements into waste containers 
after reducing their volume with the application of pressure and to 
deposit them at subterranean places which are only accessible with 
difficulty. In either case this disposal method necessitates compliance 
with especially strict regulations concerning the protection of the 
environment. 
It is known that various methods are utilized to satisfy these 
requirements; however, most of the removal procedures for contaminated 
filter elements are influenced to a very substantial extent by the desire 
to arrange the disposal processes in the most economical way without 
neglect of the requirements of the legislature. The filter maintenance and 
the necessary labor at the site of operation, which labor is concerned 
with the disposal of the filter in addition to the subsequent final 
removal by combustion or transport to a suitable place of deposit, by 
means of appropriate devices in compliance with the desired safety 
requirements, result in an effort which can be calculated in its magnitude 
and which effort is known to result in substantial expenses for the 
operator of the type of installation which was described above. Although 
the disposal expenses are not in any case even closely related to the 
procurement cost and to the actual usefulness and efficiency of the 
filter, the desire for safety in this field of application, which is based 
on legislation, cannot be disregarded. 
With regard to the matter described above, the present general state of the 
art shows two methods for the removal of contaminated filter elements 
which are especially preferred and which are described in detail as 
follows: 
1. Mechanical reduction of the volume of the contaminated air filter 
elements by means of shredder installations, impact mills or multiple saw 
and installations with subsequent compression by means of bailing presses 
or a pelletizing of the comminuted residual filter parts by means of 
suitable devices before storage in standardized 200 liter or 400 liter 
waste containers or waste drums. 
2. Mechanical comminution for the disposal process of especially 
constructed air filter elements after separation of the filter frames, 
which consist of wood or metal, from the filter media by stamping or 
multiple separation by means of sawing or pressing. The subsequent 
mechanical separation of the individual filter parts serves for the direct 
discharge of those materials which can be oxidized by means of combustion 
in furnaces (1001.degree. C.), or in the latter case it serves for the 
centralized or decentralized deposition of the precompressed medium parts 
in waste containers which are provided for this purpose. 
In order to perform such disposal processes, special housings with 
protective devices for the filter exchange and the appropriate and 
corresponding air filter elements were developed which, in case of a 
contamination depending on their type of construction and filter 
properties, can be exchanged in a more or less clumsy way and, finally, 
they can be removed as described. Filters with a low degree of 
contamination where the filter layers consists, for instance, of activated 
carbon or other absorption media are either equipped into waste containers 
until the contamination has diminished or they are combusted in 
appropriate waste combustion furnaces at high temperatures in case of the 
availability of these devices. All of the housings which should be 
utilized for this purpose are provided with appropriate filter change 
devices or filter exchange devices with protective bags, as described 
above, in order to protect the operating personnel during the exchange of 
the filter from contaminations or incorporations. For some filter elements 
construction for the nuclear field is mostly solved in such a way that the 
actual filter element consists of the rigid frame and a filter paper body 
in the shape of a compressible insert which can readily be released from 
the rigid frame. In this case the used filter unit which should be 
exchanged is first pulled out of the housing and is then separated from 
the rigid outer frame inside a transparent protective bag by means of a 
tear string. Following this, the volume of the contaminated parts is 
reduced in the known way by means of a crushing process or pressing 
process or by means of a sawing device or in a shredder or in an impact 
mill as a phase of preparation for the waste disposal, which is the next 
step. Prior to the process of filling, pouring or combustion, such filters 
must be comminuted to a fraction of their original volume for reasons of 
space usage. In many cases the remaining rigid filter frame, in case of a 
radioactive contamination, can be decontaminated and can be reused for the 
same purpose after some time. 
A similar version is known in the U.S.A. In this case each of the angular 
filter elements consists of four tube-shaped parts of a block which are 
glued together or sealed or which can be compressed and which, as 
independent functional units, can be separated from each other, if this is 
necessary, by a stamping process and can be mechanically compressed. 
Since the bulky and angular filter elements which were used to date could 
be placed after use, for the purpose of transport, into the round standard 
waste containers, only after they had been sawed apart or by making 
allowance for other difficulties as far as compression and comminution are 
concerned, and even then only with difficulty, there was a continuous 
search for new or similar solutions to the problem in order to be able to 
perform a simple and economical filter waste disposal without 
contamination of the environment. 
The current state of the art is mainly critized for the unreasonably high 
expenditure for manual and mechanical pretreatment, and it is further 
critized for the very expensive processing devices and the protective 
measures which have to be used in order to be able to perform the 
described removal processes in an economical and space-saving way. 
This complex situation is even more aggravated by the fact that the filter 
industry to date has usually manufactured angular filters for economical 
reasons in order to please the consumer; however, the barrel-shaped waste 
containers into which the used filters should be put after contamination 
are, in a completely contrasting way, manufactured in the form of a 
circle, also for reasons of economy and for some other undoubtfully 
advantageous reasons. However, this discrepancy in its entire magnitude is 
only completed by the inner measurements of the internationally 
standardized waste containers which are much too small as compared with 
the standardized outer measurements of the angular filter bodies which are 
customary and enjoy a world-wide distribution. 
This situation could, of course, in a simple way be remedied in such a way 
that in the future the round waste containers will be manufactured 
somewhat larger or in a fitting shape, that is, in an angular shape or in 
a quadratic shape. On the other hand, it is still possible to manufacture 
the housings and the filter bodies in circular shape and in matching 
measurements with respect to the round waste containers in order to 
achieve an agreement; however, a more detailed examination has shown that 
the manufacture of angular containers is substantially more complicated 
and more expensive than the manufacturing of containers as they were up to 
date, especially if the same strength data and pressure data are desired 
for angular or box-shaped containers as for the round shapes of 
construction which were used to date. In addition, the cost for the 
manufacturing of the filters is increased if round filter elements should 
be utilized which would match the round containers instead of the use of 
the angular filter bodies; however, since for decades thousands of filter 
installations were used which were constructed, based on the angular or 
quadratic filter element dimensions which are internationally customary, a 
general conversion to the round air filter bodies in the future by the 
operators of filter installations is possible only if allowance can be 
made for high changeover costs and high investment costs concerning the 
existing air filter installations as well as the higher prices for 
filters. The same problem exists for the 200 liter standarized waste 
containers of round shape for the reception of contaminated filter wastes 
which are internationally customary to date. The 400 liter containers with 
their larger diameters were, in most cases, so far only used so that the 
200 liter waste containers could be placed in them and sealed with 
concrete. For the intended purpose of placing the filter in these 400 
liter containers for waste deposit, these containers would possibly be too 
expensive, since in the case of sealing with concrete a still larger 
container would then be necessary. Another reason for not changing the 
shape of the filter elements or the containers is the fact that the 
existing technical installations for the operation and maintenance of the 
existing removal installations, such as telekinetic manipulators or air 
locks, have been matched to the described types of constructions and 
dimensions for years and it would be very difficult to change this. The 
operators of nuclear installations as well as the manufacturers of 
containers, air filters and housings are presented with the same multiple 
cost problems which would occur if this situation should be changed in a 
rapid and general manner. 
In this context it should also be mentioned that the contaminated waste of 
a nuclear installation which should be removed by means of oxidation or by 
means of deposition of course not always consists of used filter elements, 
but rather to a much larger extent it consists of various other materials 
which are part of the nuclear process and which have to be removed as 
waste. This also seems to be the reason for the fact that the disposal 
aspect of the filters is probably not taken serious enough. 
The regulations concerning environmental matters, disposal matters and 
deposit matters have now become more strict. In some cases the cost for 
the maintenance of such installations has increased to such an extent due 
to new regulations that sometimes the entire technical process has been 
seriously reconsidered with regard to its economical aspects. 
This is the reason why, at least as far as the filters are concerned, 
solutions to this problem are necessary which to begin with should be 
characterized by economic considerations, especially as far as the 
planning of such installations is concerned. The volume reduction 
installations and the comminution installations which were described 
above, such as, for instance, impact mills, separating devices, saws, 
shredder installations or bailing presses, necessitate the availability of 
large indoor spaces and rooms where these devices can be installed and 
which rooms are safeguarded with air locks and which rooms must be further 
safeguarded air tight and radiation protected with regard to the 
atmosphere. Furthermore, remote control devices are necessary which will 
start and control the mechanical process for the reduction of the volume 
and for the compression of contaminated filters in which case, of course, 
occasional repairs of contaminated machine parts should not be excluded. 
The present state of the art of the comminution possibilities and 
compression possibilities of contaminated filter elements results, at 
best, in the reduction of volume of a ratio of 1:3. The extent to which 
the waste containers are filled independent of their capacity in liters is 
of an order of magnitude of maximum 65% to 70%, due to the very loose 
waste material and the volume of air that is entrapped in the filter 
material. Therefore, a complete utilization of the container volume in 
spite of the solidification is, at least, presently not yet possible. 
Whether in the near future a significant improvement can be achieved at 
all, considering the present state of the art of disposal of contaminated 
filter elements, is not clear at the present time. 
SUMMARY OF THE INVENTION 
For the reasons which were explained above, the present invention is based 
on the objective first of all to circumvent the multitude of the described 
processes for the reduction of the volume of contaminated filters 
completely to simplify the exchange technique and the necessary 
maintenance protection and the expenditures connected with the handling of 
contaminated filter bodies and to create the technical basis for the 
disposal of filters by means of standardized, round, commercially 
available, regular waste containers which will result in a substantial 
reduction of the entire technical and financial expenditures, even for the 
higher pressure range, without a reduction in the present degree of 
utilization or degree of filling of the volume of the waste containers. 
This objective is met according to the invention and according to the basic 
principle of the device and the operating method of the invention in such 
a way that appropriately shaped filter elements are received by such 
housings which consist of international, commercially available, 200 to 
400 liter capacity, standardized waste containers for the nuclear industry 
which are equipped with sealable, standardized lids and which are suitable 
for the manipulator technique and air lock technique which, without a 
change of their physical appearance, fill the complete height of the 
container and the entire volume of the container up to an extent of over 
65% with compact filter layers. The filter layers are distributed 
uniformly over the entire inner cross-section of the container, or are 
offset with reference to each other, or which filter layers are located 
one on top of each other, and which filter layers consist of pocket-type 
filter paper or granular bulk material in the shape of plates, locks, 
boards, discs, rings, stars or zig-zag where, during the working phase of 
the filter, the waste containers are freely suspended at the filter 
installation with some distance to the floor. Above each waste container a 
domed lid is put after removal of the standard lid, which domed lid is 
equipped with cube flanges at both sides of the air entrance and the air 
exit, and with test grooves. The domed lid can be tightly connected with 
the waste container and the inserted filter element by means of detachable 
screw devices or with remote control elements which activate lever 
systems. The domed lid is connected by means of flanges with one of each 
air current carrying dusty-air channel or clean-air channel, which 
channels can be located one on top of the other or one next to the other. 
For for the performance of a contamination free, manual filter exchange by 
means of a transparent, protective tube connection between the container 
flange and the domed lid flange at each part a circumventing, 
self-fastening, elastic, known rim with multiple grooves is located, into 
which grooves the elastic protective tube connection can be squeezed in a 
known way. During the exchange phase each of the waste containers can be 
removed and lowered from the air channel in the range between the floor 
and the container or can be lifted up to the air channel in order to be 
connected with it by means of bolts and where the lifting and lowering of 
the waste container is performed by means of a lift truck. 
In order to use such a filter element in a housing with an exchange device 
in accordance with the further modification of the invention by way of the 
correct method, it is necessary that before the exchange of the filter 
elements the throttle valves of the fresh-air tubes and the exhaust-air 
tubes, which valves can be activated with levers, are at first closed at 
the filter installation with the support; and that after removal and 
lowering of the waste containers from the filter installation to the floor 
or onto a movable transport cart or lift truck the protective hose, which 
connects the domed lid and the waste container, is pulled apart and in its 
middle section is sealed and separated. Only then the final covering or 
closing of the waste container is performed by means of the appropriate 
standardized lid, which is screwed on with simultaneous enclosure of the 
sealed-off protective tube and the used filter body, which is now inside 
the container. 
The above objective is furthermore solved by the present invention by the 
fact that the standardized waste container in its entire height is filled, 
for instance, with an air or gas cleaning granular bulk material layer in 
such a way that approximately 25% to 35% of the container cross-section of 
filter-free, free space remains to the right and to the left of the filter 
layer as a space for the supply air and for the exhaust air. The domed 
lid, which is connected to an airstream carrying channel system of the 
filter installation, and which domed lid is optionally equipped with 
remote control elements (for instance, hydraulic cylinders), is divided 
inside by means of a roof-shaped separation with a test groove device into 
one dusty-air space and one clean-air space, which are tightly sealed. 
Directly connected to this are tube connections with throttle valves, 
which throttle valves can optionally be remote controlled by means of 
lifting cylinders and where in case of the filter exchange the throttle 
valves are closed, the lifting cylinders with the layer system are opened 
for the purpose of the removal of the cap-shaped domed lid with beveled 
lid edge and gasket from the waste container. The lifting cylinder at the 
bottom places the container onto an automatic set of roller skids which 
are located horizontally and which can optionally be lifted up or lowered 
onto two movable conveyor belts for transport after the standardized lid 
has been put on the container automatically. 
It is furthermore of importance for the further development in refinement 
of the invention that the standardized waste container, which can be 
lowered from a filter installation, is filled to more than 65% with a 
filter layer which is arranged in a star shape, such as for instance with 
large area folding filter paper pockets which are arranged around a 
hollow, cylindrical, air entry cross-section. The air current on the 
clean-air side is passed between the filter pockets from below to the top 
through a domed lid, which domed lid is equipped from the inside with a 
supply air tube for the dusty air which is positioned in a slanted fashion 
within the space of the lid. The one end of the supply air tube is 
equipped with a closable test groove and is connected tightly to the 
filter element during the operation phase, whereas the other end of the 
tube which extends through the upper lid wall is tightly connected via a 
flange connection with round or angular tube. The exhaust air is removed 
from the domed lid directly via a tube connection, and where for the 
contamination free filter exchange the container and the domed lid are 
each equipped with a rim, into which rim a transparent protective tube can 
be squeezed. 
The basic idea of the invention is furthermore defined by the fact that the 
inner space of the standardized waste container is in its full height 
filled with at least four quadratic, zig-zag filter packages in the shape 
of pockets, which are alternately layered one on top of the other in such 
a way that in each case two free spaces for the supply airstream and for 
the exhaust airstream are created in the cross-section of the container. 
The free spaces are located one opposite of the other where it is 
necessary to seal all four corners of the filter package at the wall of 
the container with a sealant compound in such a way that, when the 
container is covered with the domed lid, a seal is automatically created 
at the filter package, which seal runs centrally and diagonally through 
the domed lid and which seal is created due to the presence of a test 
groove which separates the dusty-air space from the clean-air space, and 
the possibility exists to connect it with an air supply channel or an 
exhaust air channel by means of two tubes which are equipped with throttle 
valves. 
In a further modification and refinement of the solution of the problem on 
which the invention is based, the inner space in the full height of the 
standardized waste container is filled, for example, with a rectangular, 
board-shaped, compact, zig-zag, folding filter package in the form of 
pockets which is uniformly layered with one layer on top of the other 
layer and in such a way that at least 65% of the volume of the container 
is utilized for this purpose above each waste container a hat-shaped domed 
lid is located. Both are connected with each other with multiple grooved 
rims and a protective tube which after latching with the container 
separates the clean-air space from the dusty-air space in a gas-tight 
fashion by means of a roof-shaped and square-shaped separating part, which 
is located on the inside of the lid part, and by means of a closable test 
groove device on the rectangular, board-shaped filter package, and by 
means of an elastic gasket, whereas two sides of the container 
cross-section which are located one opposite the other are closed and the 
other sides are open with reference to the filter package. 
Another characteristic of the process of the invention is the mode of 
operation after the filter has been used. In this case it is significant 
that the waste container, which is filled with the rectangular, 
board-shaped, used filter pocket package and the gasket after its removal 
from the domed lid of the installation and in case of contamination, is 
connected with bolts to a standarized lid which fits the container 
tightly. The remaining free spaces could still be filled with additional 
contaminated waste products of the nuclear processing type before the 
container is finally closed. The filled container with the bolted-on, 
standarized lid is then ready for transport. 
In order to achieve a complete utilization of the details of the invention, 
it is furthermore necessary that the star-shaped package of filter pockets 
with the prefilter layer in the shaped of a hollow cylinder which was 
placed into the waste container is closed at the top and at the bottom of 
the V-shaped sides of the pockets, and the remaining free spaces can be 
used for the passing of exhaust air, if additional other contaminated 
materials should be placed into the container for their disposal. 
Finally, according to a further modification and refinement of the claimed 
subject, the basic construction of the invention is furthermore influenced 
by the fact that in order to avoid damage to the protective tube during 
the exchange of the filter, the bottom portion of the waste container edge 
is equipped with tightly welded cover nuts, which are closed at the 
bottom, instead of the commercial spacer bolts, and the domed lid with the 
rim or the optional standarized lid without rim is attached to the edge of 
the container with bolts, thereby enclosing the contaminated protective 
bag and the contaminated filter, and where the rim which is located at the 
edge of the container can directly be transported to a deposit site 
together with the waste container as a disposal part or as a long-term 
deposit part in case of disposal.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The filter installation according to FIG. 1 shows in detail that the filter 
elements, which are sealed in the waste containers 1 and which are not 
shown, are directly connected to supply air ducts and the exhaust air 
ducts 7 by means of the domed lids 4 and the tube connections 3 and the 
flanges 6. The support structures 2 for the supply air ducts and exhaust 
air ducts 7 are of such height that a space 11 is formed under the freely 
suspended waste containers 1, which space 11 makes it possible that during 
the filter exchange phase and before the filter exchange phase, a movable 
lift truck 10 can be pushed under each of the waste containers 1 to be 
exchanged. After the removal of the tightening elements or connecting 
elements 5, the waste container 1 is lowered from the stationary domed lid 
4 to the floor by means of the lift truck 10. In this way the protective 
tube, which is squeezed in by strings and which is not shown, is pulled 
apart between the rims 8 and 9 in such a way that the known sealing 
process and separating process can be performed for the purpose of the 
sealing of the domed lid 4 and the container 1. 
It is unequivocally evident from FIG. 2 that in this way a row of waste 
containers 1, which are equipped with filter elements and which are 
connected in series or in a parallel fashion, can be arranged directly 
below air ducts 7, which air ducts are appropriately supported with a 
support structure 2. The exhaust air tubes 3 partially penetrate the 
supply air duct 7, whereas the tube connections 3a which are located on 
the domed lids 4 at the supply air side are only tightly sealed and 
connected to the corresponding bottom part of the duct. A reverse 
arrangement is also conceivable such that the connecting tubes 3 and 3a 
are connected to the air ducts 7. 
FIG. 3 shows a waste container 1 with the filter elements 48 and 49 which 
are located offset with reference to each other, which waste container 1 
was already removed from the domed lid 4 and lowered by means of the lift 
truck 10. During this process the tightening elements or connecting 
elements 5 remain at the circumventing flange of the stationary domed lid 
4. The protective tube 9, which is pulled apart and extends between both 
the rims 8, can then be separated in an air-tight fashion by means of a 
sealing and separating device. 
Such a necessary separating device 14 for the separation of the protective 
tube 9 during the filter exchange is indicated in FIG. 4, whereas FIG. 5 
should show the situation that exists if the throttle valves 13 are closed 
by means of the levers 12 and the waste container 1 with the lift truck 10 
is pulled away laterally from the filter installation 2 in the area of the 
floor 11. The remainder of the tube 9 at the domed lid 4 is pulled into 
the new protective tube 9, by hand grasping the remainder of old tube 
between a pinched portion of the new protective tube 9 which new 
protective tube is attached to the rims of the container 1 and the domed 
lid 4 after a new filter container 1 is placed under the domed lid 4. The 
used container 1 is closed by means of a standarized lid 15, and the 
container is then ready for shipping. 
FIG. 6 shows a completely automatic version of the filter element in 
accordance with the invention which can be operated by remote control, and 
FIG. 6 shows further the waste containers 1. Such a solution is especially 
perferred in such areas of application which are characterized by very 
extensive contamination, such as, for instance, in hot cells. The waste 
container 1 with the filter layer 16, which was poured into it, is pressed 
against the domed lid 4 in an air-tight manner by means of leveraged 
tightening devices 20 (for instance, hydraulic cylinders), which domed lid 
4 is equipped with a funnel-shaped, circumventive edge cover 4a. In this 
way the test groove device 22 of the domed lid 4 partially penetrates the 
elastic gasket 16a of the filter layer 16 which was poured or filled into 
the container 1. The domed lid 4 separates the dusty-air side from the 
clean-air side by means of a roof-shaped separation piece 21, and in this 
way the waste container 1 is, together with the lid edge gasket 4a, sealed 
from the surrounding air. During the operation of the filter the throttle 
valves 23 in the connecting tube 24 and 25, which are located on the 
supply air side and on the exhaust air side, respectively, on the domed 
lid 4, are opened by means of the tightening elements 23a (for instance, 
hydraulic cylinders). The filter exchange of the used and contaminated 
filter layer 16 in the container 1 is performed in sequence, as described 
below: 
The tightening elements 23 are shifted by means of remote control to the 
closed position of the throttle valves 23. The clean-air duct and 
dusty-air duct 19 is therefore hermetically sealed. Then, all three 
leveraged tightening elements 20 at the domed lid 4 are unlatched. In this 
way the container 1 with the filter layer 16 can be freely moved in a 
downward, vertical direction. In this way the extended lifting cylinder 28 
with the pressure lid 29 which is located under the container 1 is 
subjected to a load, and finally the lifting cylinder is shifted downward 
to such an extent by the release of a paralysis circuit until the 
container 1 is positioned on a dual conveyor belt or on a powered roller 
conveyor 30. In this way the waste container 1, including its used 
contents and after it has been closed with the standardized lid 15, can 
automatically be moved horizontally to its discharge position. Prior to 
the start-up of a new container with a new filter layer, the sequence of 
operation steps is carried out in the reverse order of sequence. During 
this procedure a remote controlled last check for tightness between filter 
16 and the domed lid 4 and, on the other hand, a check of the seal between 
the clean-air space 24 and dusty-air space 25 by means of the test groove 
device 22 can be performed as it was practiced in a known way to date. 
Simultaneously, the tightening effect of the tightening elements 20 can 
also be checked. The conveyor belt 31 or the entire roller conveyor 30 can 
also be vertically moved instead of the lifting cylinder 28. 
FIG. 7 shows the free spaces 17 and 18, which remain between the filter 
layer and which are necessary for the passing of the supply air and 
exhaust air via the connecting tubes 24 and 25. In addition, FIG. 7 shows 
the arrangement of the tightening elements 20 and the domed lid 4. 
Another modification of the container filter is evident from FIG. 8, as 
well as from the cross-sectioned top view according to FIG. 9. In 
accordance with these figures the filters installation consists, first of 
all, of round tubes 42 which are located close to each other, or it 
consists of angular supply air ducts and exhaust air ducts 43 which are 
arranged on a support frame 2. Connected to this via the flange 
connections 41 and 45 are the connecting tubes 35 and 38, the domed lid 
36, and the waste container 1 which is attached to it. The domed lid 36 is 
equipped with a piece of tubing 37 for the passing of the supply air, 
which piece of tubing 37 extends in a slanted position through the space 
inside the lid. The piece of tubing 37 is equipped at its lower end with a 
circumventive, completely round test groove device 39, which in its 
tightened condition contacts the filter layer 32 and its gasket 32a. The 
filter layer 32, which is contained in the waste container 1, consists of 
a zig-zag shaped pocket filter layer 32 which is arranged in a star-shaped 
pattern around a hollow cylinder 33. As an option, the filter layer 32 can 
also consist of high-quality filter paper. The dusty air passes from the 
tube 40 and 42 or 43 through the entire space of the domed lid 36 to the 
filter 32, and after the cleaning process it is passed from this point 
through the free space in the lid 44 into the exhaust air pipe 35. At the 
edge of the domed lid 36 and at the edge of the waste container 1, one 
circumventive multigroove rim 46 is attached, as shown in FIG. 8, into 
which rim 46 a clear protective tube 47 is squeezed by means of strings 
which are inserted, and which protective tube 47 is of sufficient length 
for the exchange process. In this case the waste container 1 is also 
lowered by means of a movable lift truck 10 during the exchange process 
after removal of the tightening elements until the protective tube 47 is 
unfolded to such an extent that it can be sealed and separated to form two 
halves. 
As another characteristic, FIG. 10 shows as a drawing a block or 
board-shaped filter insert in a waste container 1 in which case, for 
instance, four zig-zag pocket filter packages 48 and 49, which are of the 
same size, are alternately layered one on top of the other in such a way 
that at least 65% of the container is filled. In this way two exhaust 
sides are created for each two supply air sides, which are located 
diagonally. The two exhaust sides are the optimally utilized free spaces 
50 and 51 at four sides of the container space 1, which are shaped like 
the segments of a circle and which are utilized for the pasing of the 
supply air and the exhaust air, which airstream is passed through both of 
the connecting tubes 56 and 57 and through the domed lid 53, the 
directions of which are currents are counter-current with reference to 
each other. 
It is evident from the drawings of FIG. 11 and FIG. 12 in which way the 
dusty-air space 56 is separated by means of a straight test groove bar 54 
from the clean-air space 57 in the domed lid 53 diagonally from one edge 
to the other edge of the filter package 48 and 49. The corners or edges, 
respectively, of the filter layer 48 and 49 which contact the inner edge 
of the container are each sealed by a special seal 52. 
FIG. 12 shows again in detail as a cross-section of the domed lid 53 the 
throttle valves 58 and the vertical separating bar 54 with the test groove 
55 between the clean-air space and the dusty-air space. The corresponding 
container cross-section with the container 1 characterizes the position of 
the filter element gasket 1a on the filter layer. 
The drawings of the FIGS. 13, 14, 15 and 16 show still another modification 
of a filter element in a waste container. This is a filter package 59 
which has been uniformly layered in a zig-zag fashion, one layer on top of 
the other, where the airstream passes in the shape of the letter U through 
the filter layer 59 and the container 1. 
FIGS. 13 and 16 show in the domed lid 60 the roof-shaped division 61 with 
adjoining test groove device 64 which exerts a pressure on the gasket 65 
of the filter package 59 after the device has been assembled. 
FIG. 16 shows free spaces at the filter package which are separated from 
the outer air and which are hatched black. 
FIGS. 14 and 15 should show and elucidate the position of the multiple 
groove rims 66 and 67 and the condition of the sealed protective tube 68 
after the container and the domed lid have been pulled apart. 
FIGS. 17, 18, 19 and 20 are cross-sections of both of the basic waste 
container filter layer systems and, that is, in one case in the form of a 
granular bulk material 69 or as a upper filter block, and in case of the 
other version in the form of a star-shaped, folding paper filter 72 with a 
cylindrical, three filter layer 73 which was inserted on the dusty-air 
side. Both of the waste container systems, according to FIGS. 17 and 19, 
are closed with a commercial, standarized lid 15 for the purpose of 
delivery as well as for the purpose of transport for disposal. 
In case of the example as shown in FIG. 17, a tightly folded paper filter 
layer 69a can be arranged before and after the filter layer for the 
purpose of prefiltering and refiltering in addition to the granular bulk 
material layer 60 with the gasket 71. 
FIG. 18 is a drawing of a cross-section of the container 1 with the filter 
layers 69 and 69a and the free spaces 70. 
FIG. 20 shows the remaining free spaces in the waste container 1 for the 
clean-air exhaust 75. The V-shaped filter pocket covers 76, which are 
hatched black, result necessarily in a passing of the air through the 
filter plates 72 into the clean-air spaces 75. The hollow cylinder 74 with 
the prefilter layer 73 represents, in this case, the air supply side or 
the dusty-air side. 
FIG. 21 is the drawing of a cross-section which mainly shows the actual 
attachment of the multi-groove rims 77 and 78 at the domed lid 4 and at 
the waste container 1. In order not to damage the protective tube 81 
during the maintenance, preferably cover nuts or blank nuts 79 are tightly 
welded below and around the container edge 1 for the reception of the 
bolts 80. 
FIG. 22 shows how the bolts 80 are passed through the domed lid 15 and 
through the contaminated protective tube 81 and how the bolts 80 are 
tightly screwed to the container 1. In this case the rim 78 remains at the 
container 1 and is not removed for the final deposit. This construction 
ensures that the contaminated protective tube 81 and the contaminated 
filter element are packed contamination protected in container 1 and that 
contaminated material cannot enter the environment. 
The advantages which can be achieved with the invention consist especially 
in the fact that the waste containers, which anyhow to a large extent in 
case of an intended final deposition are looked upon as packaging for the 
contaminated filter wastes, can simultaneously be used as one-way filter 
housings. 
In addition to this increased efficiency and degree of utilization of the 
waste containers and disposal containers, the connecting installations for 
waste container filters can also be manufactured in a substantially more 
space saving and simple fashion, and they can be manufactured from normal 
tube ducts or air ducts. 
In addition to the simple and extremely safe filter exchange technique and 
container exchange technique, there are still substantial savings of 
investment costs for the operator of nuclear installations because the 
procurement of special housings for the filter elements with tightening 
devices and maintenance protection is eliminated due to the placement of 
waste containers or disposal containers. The handling of the filter 
exchange process, which was necessary to date and which required a lot of 
expenditures and effort with the subsequent extensive additional 
operations for the disposal of the contaminated filters in order to 
encapsulate these contaminated filters finally in compacted form into the 
waste containers which were to be deposited, is also eliminated. 
According to the present state of the art of the technique of mechanical 
comminution of contaminated filters for the purpose of waste disposal, a 
reduction in volume of maximum 1:3 can be achieved; however, in practice a 
filter element with the dimensions 610 by 610 by 292 millimeters with an 
air passage capacity of 1700 cubic meter per hour could, at best, be 
compressed to the dimensions of approximately 350 by 200 millimeters due 
to the spring-back resilience properties of the parts of the filter. Even 
in case of pelletizing of the pure filter medium without the waste from 
the frames, a further reduction of the volume is hardly possible. Thus, 
under the most favorable conditions only up to four comminuted or pressed 
filter elements of the dimensions mentioned above could be filled into a 
200 liter waste container. 
Four of such filters combined result in an air volume of 6800 cubic meters 
per hour which corresponds approximately to the volume passage of the 
filter in accordance with the invention in the waste container. As 
compared with the air volume to be filtered of four filter elements of the 
above example, the system in accordance with the invention is not at all 
at a disadvantage. On the contrary, the possibility exists to save the 
cost of not only at least three filter housings with the partially rather 
complicated technical effort and expenditures, but also the exchange 
operation and maintenance work for these three installations with the 
necessary safety measures by using the device in accordance with the 
invention. In case of the waste containers of a capacity of 400 liters 
which were also used to date in the nuclear field, the effectiveness of 
the invention is, of course, much larger. 
Another advantage of the invention results due to the possibility to 
operate, for instance, a 200 liter container already because of the 
extremely small space requirement of one filter unit and rather for the 
benefit of a longer service life at preferably only 2000 cubic meters per 
hour and with the same pressure difference than to date instead of the 
large air volume to be filtered of more than 6000 cubic meters per hour. 
In this way the filter service life of 12 to 16 months, which was 
generally customary to date, can be increased threefold. This, of course, 
has a favorable effect not only with reference to the decreased frequency 
of the exchange intervals with the technical safety risk, but also with 
reference to cost performance matters. 
Furthermore, it must be mentioned that the equipment in accordance with the 
invention allows the manufacturing of a filter unit which can be remote 
controlled for application in hot cells, which filter unit can function 
during the exchange phase in a completely automatic fashion without the 
utilization of expensive telekinetic manipulators with the corresponding 
operating personnel. 
Furthermore, it is of advantage that the waste container can be filled with 
a filter layer which consumes little pressure; for instance, the waste 
container can be filled with a granular bulk material layer. This can 
simultaneously be connected with the utilization of a coarse filter and a 
fine filter which can be located before or after the granular bulk 
material layer. This is an advantageous embodiment of a triple effect 
filter in the smallest space which will practically eliminate at least two 
filter installations of the type of construction which was customary to 
date. 
Due to the special construction of the stationary domed lids for the 
convering of the containers with the connecting tubes for supply air and 
exhaust air which are equipped with a throttle valve, there exists still 
another advantage insofar that the waste containers with the built-in 
filter elements can be connected by means of flanges and without special 
auxiliary equipment to air ducts which are positioned one next to the 
other or one above the other. 
The exchange operation of the suspended filter containers with the aid of a 
lift truck includes also the solving of the transport problem, since such 
a transport truck was anyhow necessary to date for the delivery and 
removal of the filters. 
The time loss and the volume reductions and pelletizing operations of the 
filter elements which had to be performed in rather awkward ways and with 
extensive safety measures, utilizing saws, shredders or presses and the 
rooms which are necessary for these operations, including the additional 
necessary operating personnel, can be saved to a large extent at least for 
the disposal process in accordance with the invention as far as the filter 
is concerned. The period of time during which the personnel is exposed to 
radiation during the filter exchange and during the filter removal is 
reduced to a minimum, since this process occurs only once during a short 
stay at the filter. To date, this operation had to be carried out at four 
different filter installations. 
Since the waste containers which were used to date can anyhow only be 
filled and utilized up to 65% in spite of high pressures and due to the 
unavoidable air encapsulation and the partially incompressibility of the 
filter material, the idea in accordance with the invention was not too far 
fetched to insert the filter element in as compact a form as possible into 
the waste container, that is, in such a way that approximately 65% of the 
filter housing or of the waste container is utilized. 
Therefore, 35% of the container volume still remains for the unhindered 
passage of supply air and exhaust air which can be looked upon as 
sufficient. 
For example, it is possible to insert and store a filter package which 
consists of filter paper in the shape of pockets in a waste container with 
a volume of 200 liters and with an inner diameter of 560 millimeters and a 
height of approximately 800 millimeters in such a way that an air volume 
of approximately 6000 cubic meters per hour can be handled or the 
correspondingly comparable long service life can be achieved. 
The state of the art of the filter disposal which needed to be revised and 
the problems which were pointed out above of the cumbersome and partially 
unsafe, expensive and time consuming, exchange, maintenance and disposal 
operations concerning contaminated filter elements which were customary to 
date are very substantially reduced utilizing the proposed solving of the 
objective of the invention, and with the improvement of the degree of 
safety the danger to the operating personnel and to the environment is 
reduced as well.