U.S. patent number 3,690,045 [Application Number 04/796,695] was granted by the patent office on 1972-09-12 for air filter.
Invention is credited to Gerhard Max Neumann, Lentzeallee 93, Berlin, Republic of DE.
United States Patent |
3,690,045 |
|
September 12, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
AIR FILTER
Abstract
A filter for separation of suspended substances from a flow of
air or gas comprises a contaminated gas duct, a filtered-gas duct,
each duct having a stub, a disposable filtering assembly having an
inlet stub and an outlet stub intended to be attached to the
contaminated-gas stub and the filtered stub respectively, and two
tubes of flexible sheet material attached to the inlet and outlet
stubs respectively. Each duct stub has two gas-tight securing
means, the first securing means allowing attachment of the
corresponding tube the second securing means allowing addition of
successive replacement filtering assemblies, after sealing and
cutting of the tube, in such a manner that the remnant of tube
attached to the duct stub may be detached from the first securing
means after being surrounded by a new tube attached to the second
securing means. The new tube is subsequently secured by the first
securing means and released from the second securing means.
Inventors: |
Gerhard Max Neumann, Lentzeallee
93, Berlin (33, Federal), Republic of DE (N/A) |
Family
ID: |
5694504 |
Appl.
No.: |
04/796,695 |
Filed: |
February 5, 1969 |
Foreign Application Priority Data
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May 3, 1968 [DE] |
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17 57 388.5 |
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Current U.S.
Class: |
55/356; 55/358;
55/466; 55/482; 55/521; 55/DIG.9; 55/481; 55/490 |
Current CPC
Class: |
B01D
46/001 (20130101); B01D 46/0013 (20130101); B01D
46/10 (20130101); B01D 46/521 (20130101); B01D
46/0091 (20130101); B01D 46/008 (20130101); Y10S
55/09 (20130101); B01D 2275/203 (20130101) |
Current International
Class: |
B01D
46/04 (20060101); B01D 46/42 (20060101); B01d
046/00 () |
Field of
Search: |
;55/428,350,481,478,356,358,466,482,490,521,DIG.9 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
german Printed Application (A), No. 1,091,415, KL 50e8, Printed
October .
20, 1960. .
SGN Bulletin by Nuclear Safety Systems, 551 Fifth Avenue, New York,
N.Y. .
10017, received January 20, 1967, pages 1, 10, 11, 12, 13, 19, 20,
21, .
and 22. .
Ventilation and Air Purification Equipment for Civil Defense
Protective .
Shelters, Flanders Filters Incorporated, Riverhead, New York,
Received .
September 24, 1965, pages 6, 7, 8, 14, 15 and 16..
|
Primary Examiner: Dennis E. Talbert, Jr.
Attorney, Agent or Firm: Karl F. Ross
Claims
I claim:
1. A gas-purification filter comprising: an incoming duct for
dust-laden gas terminating in a first stub; an outgoing duct for
purified gas terminating in a second stub parallel to said first
stub; a filter casing provided with an inlet stub and an outlet
stub coaxially confronting said first and second stubs,
respectively; rail means parallel to the axes of all said stubs
supporting said casing for displacement between an operative
position proximal to said ducts and a withdrawn position remote
therefrom, said inlet and outlet stubs sealingly engaging said
first and second stubs, respectively, in said operative position; a
pair of accordion-pleated flexible synthetic resin tubes with
extremities releasably clamped to the confronting ends of said
inlet and first stubs and of said outlet and second stubs,
respectively, said tubes being sufficiently deformable to permit
removal of said casing to said withdrawn position with
disengagement of said stubs yet without unclamping of said tubes;
and pivoted latch means on said rail means for alternately locking
said casing in said operative position and facilitating detachment
of said casing from said rail means upon removal to said withdrawn
position.
2. A filter as defined in claim 1 wherein each of said stubs is
provided with an external collar having two parallel grooves,
further comprising a pair of elastic bands for each stub receivable
in said grooves thereof for alternate engagement with respective
tube extremities during replacement of a remnant of a severed tube
by a fresh tube.
3. A filter as defined in claim 1 wherein said ducts are formed by
respective compartments of a common housing, said rail means being
secured to said housing.
4. A filter as defined in claim 3 wherein said rail means comprises
a pair of channel beams bracketing said casing.
5. A filter as defined in claim 4 wherein said channel beams are
end portions of a single rail member bent into U-shape.
6. A filter as defined in claim 1 wherein said latch means
comprises a swingable holder and a clamping screw on said
holder.
7. A filter as defined in claim 1 wherein said casing comprises a
prismatic box with frustoconical covers on opposite sides thereof
respectively bearing said inlet and outlet stubs.
Description
The present invention relates to a filter device for separation of
suspended and in particular radioactive substances from a flow of
air or gas.
The filter devices normally employed for separation of suspended
substances consist of a filter housing traversed by the gas to be
purified, this housing having arranged in it in a sealed manner
filter elements situated transversely to the gas flow. Openings
closable by means of a cover and externally operated clamping
elements for sealing contact, pressing on the filter elements
within the housing, are provided in the filter housing for
replacement of the filter elements, as required after saturation of
the same.
The application of devices of this nature to the separation of
suspended radioactive substances in nuclear plants, for example,
entails the requirement that the necessary replacement of a filter
element saturated with dust by a fresh filter element should be
performed in such manner that the personnel is protected reliably
against injury by radioactive suspended substances. To this end,
the saturated filter element must be stowed in a sealed protective
bag during removal from the filter housing. At the same time, the
opening must be reliably sealed off circumferentially during the
replacement, that is, by the protective bag, so that the personnel
is protected against direct contact with radioactively contaminated
substances. The time required for the exchange of filter elements
must be as short as possible, so that the personnel may be
protected against radiation damage at high levels of activity.
In the case of air filter devices of this kind, employed in nuclear
plants, an oval marginal ring having several uninterrupted grooves
in its surface has been conventionally arranged around the opening
of the filter housing. During replacement of the filter element, a
bag of synthetic material is secured in the grooves of the marginal
ring. The cover of the housing opening must be opened initially, in
many instances through the bag itself, and the clamping device for
the filter element must be freed. The filter element saturated with
dust is then pulled into the bag. The protective bag is sealed off
by welding, so that the filter element is situated within a sealed
plastic bag, whereas a portion of the plastic bag sealed by the
severing weld, is left on the marginal ring. A fresh filter element
stowed in another plastic bag is inserted into the opening of the
housing in such manner that the protective bag containing the
filter element is initially secured in an unoccupied groove of the
marginal ring, whereupon the weld-sealed remainder of the previous
plastic bag situated on an anterior groove is pulled off the
marginal ring, the filter element is pushed into the opening, the
clamping device accessible from the outside is operated, and the
opening is sealed off by means of a cover. The same procedure must
be applied for replacement of the next filter element. This known
device causes considerable risks, owing to the structure of the air
filter housing and to the application of the plastic bag to the
filter element. There is the risk that the unwieldy filter element,
possessing a rectangular shape as a rule, may damage a protective
bag made of plastic sheet, so that radioactively contaminated
suspended substances may spread the contamination to the
environment through the protective bag. Even if the most stringent
precautions are applied, damage of this kind cannot always be
prevented from occurring to the plastic bag during the extraction
of the filter element, particularly since the filter elements are
of relatively great size and the plastic bags must be dimensioned
accordingly. A substantial further disadvantage resides in that a
relatively long period elapses owing to the unwieldy handling
operations required for replacement of the filter element, so that
the personnel must be relieved several times in plants of great
size during the replacement operation in view of the radiation
danger existing at the high levels of activity. In view of the
reasons stated, the operation for replacement of a filter element
is dangerous to the personnel, in the case of this known device.
The relatively large sealing area between the filter element and
the housing is considered to be yet another disadvantage, involving
correlatively great contact thrust forces to be exerted by the
sealing or clamping elements.
In the case of nuclear plants of greater size in particular, air
filters of special structure, such as pot filters have accordingly
been employed, in which the contaminated filter elements are
removed from the filter housing by means of remotely controlled
manipulators, and conveyed to a storage or combustion section.
These systems, which assure excellent protection for the personnel,
are extremely costly in view of the equipment, labor and structural
expense involved, so that the general demand prevails in this
sphere of application for arrangements allowing the radioactively
contaminated filter elements saturated with dust to be replaced in
a minimum of time by the personnel without requiring unwieldy, and
possibly dangerous, servicing operations.
According to the invention there is provided a filter for
separation of suspended substances from a flow of air or gas,
comprising a contaminated-gas duct, a filtered-gas duct, each duct
having a stub, a disposable filtering assembly having an inlet stub
and an outlet stub intended to be attached to the contaminated-gas
stub and the filtered-gas stub respectively, and two tubes of
flexible sheet material attached to the inlet and outlet stubs
respectively, each duct stub having two gas-tight securing means,
the first securing means allowing attachment of the corresponding
tube, the second securing means allowing addition of successive
replacement filtering assemblies, after sealing and cutting of the
tube, in such a manner that the remnant of tube attached to the
duct stub may be detached from the first securing means after being
surrounded by a new tube attached to the second securing means, the
new tube being subsequently secured by the first securing means and
released from the second securing means.
A feature of the invention is that the securing means may be
continuous grooves formed in the duct stub.
Another feature resides in that the filter assembly consists of a
middle portion open at both ends, corresponding to the
cross-sectional shape of the filter element, and of two
funnel-shaped covering portions, each carrying a connector stub,
and overlapping the middle portion with intercalation of seals
placed on the filter element, and joined to the central portion,
e.g., by means of liquid hardenable substances, to form an integral
structural unit.
Owing to the arrangement of the filter element within a filter
assembly possessing connector stubs, according to the invention, it
becomes superfluous to employ the onerous arrangement and operation
of complex gas-proof clamping devices for sealing the filter
elements, since sealing is now directly effected in a simpler
manner on the filter unit. It is no longer necessary to extract the
filter elements from the filter housing, since the filter assembly
receiving the filter element may have its connecting flanges
disconnected externally from the flanges of the duct.
Owing to the incorporation of the two connector stubs with the
overlapping flexible protective tubes, and thanks to the
displaceable arrangement of the filter assemblies in a guide beam
of the duct, it is possible by displacement of the filter assembly
relative to the duct to sever and weld the stretched plastic tubes
in the middle, so that the connecting flanges of the filter unit as
well as the flanges of the duct are sealed off in gas-tight and
safe manner. The filter assembly containing the saturated filter
element is then withdrawn from the beam on the duct and carried
away for destruction by storage of incineration. A fresh filter
assembly is inserted into the beam on the air duct, fresh
protective tubes being connected between the connector stubs of the
filter assembly and of the duct at the same tine. The assembly is
then pushed into the operating position and the flanges situated at
the extremities of the connector stubs are joined to one another in
sealed manner by means of resilient clamping elements releasable
from the outside.
An embodiment of the filter according to the invention is
characterized in that the connector stubs of the filter assembly
are arranged coaxially relative to each other, and that the filter
assembly has projecting pegs on opposite sidewalls of the middle
portion arranged displaceably in transverse direction relative to
the axis of the connectors in a frame built up from channel
sections. The connector stubs of the ducts and the connector stubs
of the filter assembly are equipped terminally with matching
sealing flanges which may be closed in hermetic manner by means of
rapid-release clamps engaging same. In this embodiment, the filter
assembly is intercalated between the two spaced flanges of an air
duct. The displacement of the filter assembly for the purpose of
replacing the same should occur transversely to the axis of its
connector stubs.
In the case of filter plants of greater size in which it is
mandatory to employ several filter assemblies of this nature, a
relatively great floor or installation space is necessary in view
of the required transverse displaceability of the filter
assemblies. A modified embodiment possesses the advantage of
requiring a minimum of space for installation purposes. It is
characterized in that the filter assembly connector stubs are
situated parallel to each other on one side of the filter assembly,
and that a main air-duct has a partition situated between its
connector stubs for division into contaminated-air and pure-air
passages. Rows of connector stubs for reception of a row of filter
assemblies, arranged one beside the other, may be provided at one
or both sides of the main air duct.
Channel-section beams may be arranged on the duct, bearing the
filter assembly in a manner enabling their displacement relative to
the axial direction of the connector stubs. This embodiment offers
the possibility that a multiplicity of rows of connector stubs may
be provided, adjoining the two opposed sides of a box-like duct
divided by a partition into a contaminated-gas passage and a
pure-gas passage, so that a multiplicity of filter assemblies
containing filter elements may be arranged on one duct. The filter
assemblies may be arranged contiguously, since a single
displacement perpendicular to the side of the duct is necessary for
replacement of the filter assemblies, owing to the presence of the
connector stubs.
Another feature of this embodiment resides in that pivoted latch
means in the form of spring-loaded or analogous screw clamps, which
are downwardly tippable, are employed to establish the sealed joint
between the connector stubs of the filter assemblies and the
connector stubs of the duct, and secure the filter assemblies at
the extremities of the beams or rails. In this case the connector
stubs of the filter assemblies each possess a sealing flange, and
the connector stubs of the duct each possess a contact surface
equipped with a seal and receiving the sealing flange. The
application of clamping elements engaging the flanges of the
connector stubs becomes superfluous, thanks to the provision of the
spring-loaded screw clamps, since the latter themselves ensure that
the filter assembly is pressed in sealing manner against the duct.
These clamps have the additional advantage that they are
self-adjusting, thanks to their spring-loading, to take up any give
of the seals.
The invention will now be described in detail with reference to the
accompanying drawing, which illustrates the invention in a
non-restrictive sense. In the drawing:
FIGS. 1A to 1F are diagrammatical illustrations of different stages
of operation of one embodiment, showing the substitution of a fresh
filter unit for a contaminated one;
FIGS. 1A to 1F are sectional detail views relating to FIGS. 1A-1F,
respectively;
FIG. 2 is an illustration of a modified embodiment of an air duct,
in elevation;
FIG. 2A is a section along the line IIA-IIA of FIG. 2;
FIG. 3 is an illustration corresponding to FIG. 2 of a complete
apparatus with filter units installed, in side view;
FIG. 3A is an elevational view of the apparatus of FIG. 3;
FIG. 4 illustrates a single filter unit comprising a filter element
in side view;
FIG. 4A is a plan view of the filter element of FIG. 4;
FIG. 5 is an enlarged illustration of a detail of FIG. 4;
FIG. 6 is an illustration of the filter unit according to FIG. 4
coupled to the air duct;
FIG. 7 is an illustration of another modified embodiment in the
disconnected condition;
FIG. 8 is an illustration corresponding to FIG. 7, showing the
connected condition;
FIG. 9 is an illustrated in perspective of an air duct according to
FIG. 2; and
FIG. 10 is an illustration in perspective of an air duct, with a
filter unit disconnected.
A filter unit 1 comprising two coaxial connector stubs 2 and 3 is
shown in FIGS. 1A to 1F. A filter element 26 corresponding to FIG.
1A, is situated in the unit 1. The filter unit 1 has its connector
stubs 2 and 3 connected to the connector stubs 4 and 5 of an air
duct. To this end, the stubs 2 and 3 each possess a sealing flange
6, and the connector stubs 4 and 5 each possess a sealing flange 7.
The two corresponding sealing flanges 6 and 7 are held in sealing
contact by means of a coupling clamp 8 which is releasable from
inside or outside the protective tube.
Circumferential rings or collars 9 and 10 are situated on the stubs
2, 3 and 4, 5, a plastic tube 11 being fastened on each of these
rings, to envelop the two stubs 2, 4 and 3, 5. As shown by the
enlarged detail views of FIGS. 1A-1F, the circumferential ring 10
has two peripheral grooves 12 and 13 extending parallel to each
other, the tube 11 being clipped in these grooves by means of
elastic bands and being made of transparent plastic. The filter
unit 1 has projecting pegs 14 engaged in a frame 15 made of channel
sections. FIG. 1A shows the filter unit 1 coupled to the stubs 4
and 5 of the air duct.
When the filter element situated in the filter unit 1 is saturated
with dust and must be replaced, the coupling clamp 8 of the sealing
flanges is freed initially by action through the tube 11, whereupon
the filter unit 1 is displaced towards the right in the frame 15
according to FIG. 1B, with stretching of the plastic tube 11.
As is apparent from FIG. 1C, the plastic tube 11 is severed and
welded shut at the same time at the point 16 by means of welding
shears. The filter unit 1 is then pulled out of the frame 15,
towards the right, its two connector stubs 2 and 3 being sealed off
in gas-tight manner by the two welded plastic hose portions 11.
A new filter unit 1 is inserted into the frame 15 according to FIG.
1D. A new plastic tube 17 is clipped on to each of the
circumferential rings 9, in each case, the other extremities of
these tubes being secured in the outer grooves 13 of the
circumferential rings 10 of the stubs 4 and 5.
According to FIG. 1E, the remainder of the tube 11 present on the
inner groove 12 of the circumferential ring 10 is then pulled off
and, according to FIG. 1F, the filter unit 1 is then brought into
the coupled position corresponding to FIG. 1A. During replacement
of this filter unit 1, the remainder of the plastic tube 11 is
received in the part of the tube 17 which envelops the connector
stubs 2 and 3 of the filter unit in gas-tight manner.
FIGS. 2 to 10 show other embodiments, FIGS. 2 and 2A showing a duct
18 of rectangular cross-section divided into an upper chamber 20
and a lower chamber 21 by a central partitioning plate 19. At the
right-hand end of the upper chamber the central air inlet 20a for
the dust-laden air is situated, the air outlet 21a for pure air
being situated at the opposite end of the lower chamber 21.
Projecting stubs 2 and 3, forming an upper row leading into the
chamber 20 and a lower row leading into the chamber 21, are
situated on both sides of the duct 18. I-beams 22 are situated on
the sidewalls of the duct 18, between the stubs 2 and 3.
FIGS. 3 and 3A show filter units 23 equipped with connector stubs
24 and 25 parallel to each other and connected to the stubs 2 and 3
in the manner specified in the foregoing, description with plastic
tubes affixed to the circumferential rings. The filter units 23 may
be displaced on the beams 22 and removed, at right angles to the
sidewalls of the air duct 18.
The filter unit 23 is shown in detail in FIGS. 4, 4A and 5. This
unit comprises a prismatic central portion or casing 26 open at
both ends, and containing a coarse filter 30 and a fine filter 31.
A frustoconical cover 27 is arranged above the central portion 26,
and a similar cover 28 is arranged under the central portion 26.
The edges of the covers 27 and 28 overlap the middle portion 26
with seals 32 intercalated between the filters 30, 31 and the cover
portions 27, 28. The parts 26, 27 and 28 are combined into a
gas-tight unit by sealing the overlapping edges of each a covers 27
and 28. The connector stubs 24 and 25 carrying the circumferential
ring 9 and a sealing flange 6, at their front extremity, are
arranged on the sides of the covers 27 and 28.
FIG. 6 shows the filter unit 23 connected to the duct 18. The
filter unit 23, carried by the beam 22, is connected to the duct 18
by means of the stubs 2 and 3 which lead into the duct chambers 20
and 21. To this end, clamps 8 straddling the sealing flanges 6 and
7 are situated inside or outside the plastic tube 11 which is
secured in the circumferential rings 9 and 10.
To replace the filter unit 1, the clamping elements 8 are freed by
action through the tube 11 or from the outside of the tube 11,
whereupon the filter unit 23 is drawn off the stubs 2 and 3 along
the beam 22. The filter unit 23 is guided by means of pegs 33. The
protective tubes 11, stretched by the removal of the filter unit
23, are severed in the manner shown in FIG. 1C, whereupon a filter
unit 23 saturated with dust is pulled out of the beam 22, a new
filter unit 23 then being inserted and brought into sealing contact
with the stubs 2 and 3 with replacement of a new plastic tube.
FIGS. 7 and 8 show a further embodiment of the filter unit 23 in
which it is unnecessary to fit clamping elements on the sealing
flanges of the stubs. A beam 39 carries at its end a downwardly
tippable or foldable screw clamp 34 equipped with a compression
spring 35. As is apparent from FIGS. 3 and 3A, the screw clamps 34
bear on the rear side of the central portion 26 of the filter unit
23 whose upper and lower guiding flanges 40 bracket the beam 39.
The filter unit 23 has an upper and a lower stub 36, these stubs
carrying each a circumferential ring 9. An upper and a lower
connector stub 37, each carrying a circumferential ring 10 and a
comprising an annular contact surface 38 designed for sealing
engagement with the confronting flange 6 of a corresponding
connector stub 36, are connected to the duct chambers 20 and 21 of
the air duct 18. When the filter unit 23 has had its connector stub
36 brought into contact with the stub 37, the screw clamps 34 are
raised and tightened, so that the flanges of the filter unit 23 are
pressed in sealing manner against the seat 38. The give of the seal
is taken up continuously by the spring 35.
FIG. 9 illustrates in perspective of the air duct 18 according to
FIG. 2, comprising beams 22 and spring-loaded screw clamps 34. FIG.
10 is a similar illustration showing a duct case 41 divided by
partitions 42 into an upper dust-laden-air portion and a lower
pure-air portion. The filter unit 23, arranged on this case 41 in
the manner described above, is illustrated prior to having its
guiding pegs 33 inserted in the rails 22 which in this case form
part of a single channel beam bent into U-shape.
* * * * *