WO2014130623A2

WO2014130623A2 - Respiratory filtration device

Info

Publication number: WO2014130623A2
Application number: PCT/US2014/017302
Authority: WO
Inventors: Kent D. Anderson; Frederic LEPOUTRE
Original assignee: Unitech Services Group, Inc.
Priority date: 2013-02-20
Filing date: 2014-02-20
Publication date: 2014-08-28
Also published as: WO2014130623A3

Abstract

A respiratory filtration device adapted for use with gas masks or respirators for filtering tritiated water vapor from a gas is provided. The inventive device employs novel filter media, which has a fluting pattern in which a series of generally longitudinal ridges or flutes extend along paths having alternating lateral divergences from a generally upstanding axis (e.g., a pattern of substantially parallel wavy flutes) instead of traditional fluted paper filter media having straight parallel fluting (e.g., E Flute paper). The use of this novel filter media favorably impacts upon the tritium capture efficiency of these respiratory filtration devices.

Description

RESPIRATORY FILTRATION DEVICE

RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application Serial

No. 61/766,950, filed February 20, 2013, which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

[0002] The present invention generally relates to a respiratory filtration device, and more particularly relates to a personal filtration device adapted for use with gas masks or respirators used for filtering tritiated water vapor (i.e., water vapor where one or more of the hydrogen atoms are replaced by tritium) from a gas. BACKGROUND AND SUMMARY OF THE INVENTION

[0003] Filtering devices for use with gas masks or respirators for removing tritiated water vapor from the atmosphere are known. These devices generally consist of a disposable filter canister in the shape of a can (see, e.g., US 6,041 ,778), which attaches to a respirator face mask either directly or through a hose, and functions to remove tritiated water vapor for set time periods (e.g.,≤ 120 minutes). The canisters have bed depths that typically range from 2 to 3 inches. Prior to use, filter media within the canister is wetted by adding water to the canister.

[0004] These disposable filter canisters typically employ filter media in the form of permeable fluted paper filter media that is rolled a series of turns around a center point. The permeable fluted paper filter media has straight parallel fluting (e.g., E Flute paper).

[0005] While these disposable canisters achieve a satisfactory level of performance, there is a need to increase the level of tritium removal and extend the stay time achieved by these filtering devices as well as increase the air volume from that driven by man (20 liters per minute (LPM)) to that of machine (> 100 LPM). The present invention satisfies these needs by providing a respiratory filtration device suitable for use with gas masks or respirators, which comprises:

(a) tritium paper filter media, which has a fluting pattern in which a series of generally longitudinal ridges or flutes extend along paths having alternating lateral divergences from a generally upstanding axis;

(b) an optionally reusable canister housing adapted to receive and hold the filter media, the housing comprising a fluid inlet end, a fluid outlet end, a filter chamber interposed between and in fluid communication with the inlet end and the outlet end, and means on an upper outer surface thereof for integrally and sealably coupling the filtration device to an inlet nozzle of a gas mask or respirator;

(c) optionally, one or more desiccant packs positioned on, within, or near the filter chamber of the optionally reusable canister housing to control humidity levels of filtered air leaving the device; and

(d) a lower detachable and optionally reusable air intake cover sealably coupled to the fluid inlet end of the optionally reusable canister housing for receiving ambient air and directing the ambient air toward the filter chamber of the canister housing.

[0006] The inventive respiratory filtration device may further comprise:

(a) particulate filter media; and

(b) an optionally reusable secondary housing adapted to receive and hold the particulate filter media,

wherein, the secondary housing is located on the lower air intake cover of the optionally reusable canister housing, the lower air intake cover and the secondary housing adapted to integrally and sealably couple to one another.

[0007] The present invention further provides a gas mask or respirator employing the respiratory filtration device, as defined above.

[0008] Other features and advantages of the invention will be apparent to one of ordinary skill from the following detailed description and accompanying drawings.

[0009] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure may be better understood with reference to the following drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. While exemplary embodiments are disclosed in connection with the drawings, there is no intent to limit the present disclosure to the embodiment or embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications and equivalents.

[0011] Particular features of the disclosed invention are illustrated by reference to the accompanying drawings in which: FIG. 1 is an upper side view perspective of a preferred embodiment of the respiratory filtration device of the present invention with means on an upper outer surface thereof for integrally and sealably coupling the filtration device to an inlet nozzle of a gas mask or respirator;

FIG. 2 is a lower side view perspective of the preferred embodiment shown in FIG. 1 , showing a lower air intake cover;

FIG. 3 is a top planar view of a preferred embodiment of the filter media, which has a wave or wavy flute pattern; and

FIG. 4 is a top planar view of the filter chamber showing the preferred embodiment of the filter media shown in FIG. 3 in place within the chamber.

DETAILED DESCRIPTION OF THE INVENTION

[0012] As noted above, the respiratory filtration device of the present invention is adapted for use with gas masks or respirators for filtering tritiated water vapor from a gas. Gas masks or respirators can take the form of half-mask respirators, which cover the nose and mouth, full-face respirators, which provide a clear face mask or clear eye pieces that protect the eyes as well, and respirator hoods, which either surround the user's head and neck, or form an air-impermeable, tent-like structure around the head of the user, and contain either an internal or external filter system that clears incoming air of any toxic contaminants.

[0013] When a worker is transitioning from one work area to another, or exiting a work area altogether, the worker will disconnect his/her air supply (via a hose). Using the inventive respiratory filtration device, the worker may then turn on a battery powered blower to push air through the device and into a hose arranged in such a way as to supply filtered air to the worker's breathing zone. This obviates the need to open an emergency flap on the hood during transition between air lines due to (a) reduced oxygen levels within the hood, (b) a build-up of carbon dioxide, and/or (c) excessive fogging due to the loss of supplied fresh air, thus keeping the worker protected from tritium by reducing or eliminating tritium exposure during the "unplug" time. The inventive respiratory filtration device may also be used with a one piece suit that operates exclusively on filtered air, thereby becoming an unencumbered tether free suit. In another contemplated use, the inventive device is used with just a hood to provide filtered air to workers needing some level of protection, but not the entire body.

[0014] By way of the present invention, the inventor has discovered that the use of fluted paper filter media which has a fluting pattern in which a series of generally longitudinal flutes extend along paths having alternating lateral divergences from a generally upstanding axis (e.g., a pattern of wavy flutes) instead of traditional fluted paper filter media having straight parallel fluting (e.g., E Flute paper) favorably impacts upon the tritium capture efficiency of these respiratory filtration devices.

[0015] Referring now to FIGS. 1 and 2, reference numeral 10 has been used to generally designate an exemplary embodiment of the respiratory filtration device of the present invention. Device 10 basically comprises: tritium filter media (not shown); optionally reusable canister housing 12 having a fluid inlet end 14, a fluid outlet end 16, and a filter chamber 18 (see FIG. 4) interposed between and in fluid communication with the inlet end 14 and outlet end 16, a lower detachable and optionally reusable air intake cover 20 sealably connected to canister housing 12 for receiving ambient air and directing the ambient air toward the filter chamber 18; and means 22 (e.g., external threads) on a lower outer surface of housing 12 for integrally and sealably coupling the filtration device 10 to an inlet nozzle of a gas mask or respirator.

[0016] In this exemplary embodiment, canister housing 12 is in the form of a cylinder measuring from about 3 to about 4 inches in diameter, from about 8 to about 12 inches in length, and from about 7 to about 10 inches in bed depth. The larger bed depth, as compared to prior art cartridges having a 2 to 3 inch bed depth, allows for better filtration while reducing the possibility of the filter media drying out due to airflow imbalance or uneven air flow through the cylinder (i.e., premature breakthrough). The cylinder may be paired to another cylinder to double the processed air volume. Due to the relatively larger size of canister housing 12, it may be more suitably carried on a user's front, back, or side using, for example, a sling-type carrier.

[0017] Air intake cover 20 of device 10 may direct ambient air toward the filter chamber 18 using any suitable means including, but not limited to, a row of square, rectangular, trapezoidal, oval and/or triangular through openings 24 which extend around the perimeter of cover 20, as best shown in FIG. 2.

[0018] Air intake cover 20 may further comprise means for integrally and sealably coupling cover 20 to a secondary housing (not shown). Such coupling means may take the form of an annular ridge-like structure that extends outwardly from an outer surface of cover 20.

[0019] Filter chamber 18 has sufficient capacity to hold from about 7,000 to about

7,500 square centimeters (cm²) of tritium paper filter media. As noted above, the tritium paper filter media used in the practice of the present invention has a pattern of ridges or flutes positioned to have alternating lateral divergences from a generally upstanding axis. The fluting pattern causes increased air turbulence as ambient air travels through the filter chamber, which results in improved tritium removal. In one contemplated embodiment, the tritium paper filter media is wave flute filter media made from Grade 238 Ahlstrom Blotter paper, 90 flutes per foot.

[0020] In one such embodiment, which is best shown in FIG. 3, the fluting pattern is a series of substantially parallel wavy flute paths 26. Each wavy flute path 26 has a length generally running from the bottom to the top of filter chamber 18, and a wavelength (defined by the distance "D" between repetitions of the wave pattern (i.e., the distance between two successive crests "P" or troughs of each wavy flute path 26)) ranging from about 17.5 to about 29.2 millimeters (mm). The height of each flute in each wavy flute path 26 (measured from axis 28 to an outermost point or peak "P" of wavy flute path 26) ranges from about 1.7 to about 2.8 mm, while the left-to-right amplitude "A" of each wavy flute path 26 (defined by the perpendicular distance between the maximum left and right divergences of the wavy flute path 26 from axis 28) ranges from about 3.4 to about 5.6 mm.

[0021] In another such embodiment, the fluting pattern is a series of substantially parallel V-shaped or zig-zag flute paths, which transition back and forth across the generally upstanding axis.

[0022] As best shown in FIG. 4, tritium paper filter media 30 is rolled a series of turns around a center point and then placed within filter chamber 18, where it is held within filter chamber 18 by, for example, an edge projecting out from the fluid outlet end 16 of housing 12 and by the upper air intake cover 20 of device 10.

[0023] Prior to use, paper filter media 30 is wetted with water to a moisture content of from about 90 to about 1 10 % by weight. Preferably, the moisture content is from about 98 to about 102 % by weight. Canister housing 12 is loaded with the requisite amount of water by immersing the canister in water and holding it submerged for at least about 20 seconds.

[0024] The wetted canister is drained of excess water and then attached to the inlet nozzle of a gas mask or respirator. Once in place on the inlet nozzle, the personal tritium filtration device of the present invention allows the wearer to draw ambient air into the filtration device.

[0025] The inventive filtration device may be designed for use for periods of time ranging up to about 4 hours. Once the filter capacity has been reached, the filtration device is removed from the mask or respirator and disassembled. The filter media is discarded and the housing and air intake cover, if reusable, cleaned. New filter media is then placed in the housing and the device reassembled for use. [0026] As mentioned above, the inventive filtration device 10 may also comprise one or more desiccant packs positioned on, within, or near the filter chamber of the canister housing 12 to control humidity levels of filtered air leaving the device.

[0027] The inventive filtration device 10 may further comprise a particulate filter media, and optionally reusable secondary housing adapted to receive and hold the particulate filter media.

[0028] Suitable particulate filter media include filters in the form of non-woven fabric or fiberglass disks, bags, or pouches with substantially parallel planar top and bottom surfaces, which contain a substance, such as fiberglass or electret-type media, that traps particulate matter as air is passed therethrough. In a preferred embodiment, particulate filter media is a P100 HEPA particulate disk filter.

[0029] The optionally reusable secondary housing is basically a frame-like structure that retains or holds particulate filter media in place, and is sealably coupled to the air intake cover 20 via any appropriate means including snap fits and fasteners.

[0030] As noted above, the inventive tritium filtration device 10 may be designed for use for periods of time ranging up to about 4 hours. Once the filter capacity of both the tritium filter media and the particulate filter media has been reached, the filtration device is removed from the gas mask or respirator and disassembled. Both filter media are discarded and any reusable components cleaned. If reusable components are used, new filter media would then be placed in the appropriate housing and the device reassembled for use.

[0031] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the exemplary embodiments.

[0032] What is claimed is:

Claims

1. A respiratory filtration device suitable for use with gas masks or respirators, which comprises:

(a) a tritium paper filter media, which has a fluting pattern in which a series of generally longitudinal ridges or flutes extend along paths having alternating lateral divergences from a generally upstanding axis;

2. The respiratory filtration device of claim 1 , wherein the fluting pattern is a series of substantially parallel wavy flute paths.

3. The respiratory filtration device of claim 2, wherein the filter chamber has a bottom and a top, wherein each wavy flute path has a length generally running from the bottom to the top of the filter chamber, and a wavelength ranging from about 17.5 to about 29.2 millimeters, wherein the wavelength is defined by the distance between two successive wave crests or troughs of each wavy flute path.

4. The respiratory filtration device of claim 3, wherein the height of each flute in each wavy flute path ranges from about 1.7 to about 2.8 millimeters, and wherein the left-to- right amplitude of each wavy flute path ranges from about 3.4 to about 5.6 millimeters.

5. The respiratory filtration device of claim 1 , wherein the fluting pattern is a series of substantially parallel V-shaped or zig-zag flute paths, which transition back and forth across a generally upstanding axis.

6. The respiratory filtration device of claim 1 , wherein the canister housing is in the form of a cylinder measuring from about 3 to about 4 inches in diameter, from about 8 to about 12 inches in length, and from about 7 to about 10 inches in bed depth.

7. The respiratory filtration device of claim 1 , wherein the air intake cover directs ambient air toward the filter chamber using a row of through openings which extend around the perimeter of the air intake cover.

8. The respiratory filtration device of claim 1 , which further comprises:

(a) particulate filter media; and

9. The respiratory filtration device of claim 8, wherein the particulate filter media is selected from the group of filters in the form of non-woven disks, bags, or pouches with substantially parallel planar top and bottom surfaces, which contain a substance that traps particulate matter as air is passed therethrough.

10. A gas mask or respirator employing the respiratory filtration device of claim 1.

1 1. A method of using the respiratory filtration device of claim 1 , which comprises: wetting the tritium paper filter media in the filter chamber of the canister housing with water to a moisture content of from about 90 to about 1 10 % by weight; attaching the wetted canister to an inlet nozzle of a gas mask or respirator thereby allowing a wearer of the gas mask or respirator to draw ambient air into the filtration device for periods to time ranging up to about 4 hours; and thereafter

removing the filtration device from the gas mask or respirator, disassembling the filtration device, and replacing the filter media in the filter chamber with new filter media.

12. The method of claim 1 1 , wherein the moisture content of the tritium paper filter media is from about 98 to about 102 % by weight.