U.S. patent application number 11/401649 was filed with the patent office on 2006-11-09 for activated oxidizing vapor treatment system and method.
This patent application is currently assigned to STERIS INC., a Delaware corporation. Invention is credited to Michael A. Centanni, Gerald E. McDonnell, Iain F. McVey, Lewis I. Schwartz.
Application Number | 20060252974 11/401649 |
Document ID | / |
Family ID | 29270710 |
Filed Date | 2006-11-09 |
United States Patent
Application |
20060252974 |
Kind Code |
A1 |
McVey; Iain F. ; et
al. |
November 9, 2006 |
Activated oxidizing vapor treatment system and method
Abstract
An oxidizing liquid (20), such as hydrogen peroxide, is
vaporized (18) and the vapor is used to deactivate nerve gas,
blistering gas, or other biologically active substances such as
pathogens, biotoxins, and prions. A second chemical compound (42)
in vapor, mist, or fog form is used in conjunction with the
oxidizing vapor. In one embodiment, the second chemical
preconditions the biologically active substances to be deactivated
more efficiently by the oxidizing vapor. In another embodiment, the
second chemical boosts the reactivity of the oxidizing vapor. In
another embodiment, the other chemical reacts with the oxidizing
vapor to form an intermediate compound that deactivates at least
some of the biologically active substances.
Inventors: |
McVey; Iain F.; (Lakewood,
OH) ; Schwartz; Lewis I.; (Shaker Heights, OH)
; Centanni; Michael A.; (Parma, OH) ; McDonnell;
Gerald E.; (Basingstoke, GB) |
Correspondence
Address: |
Thomas E. Kocovsky, Jr.;FAY, SHARPE, FAGAN, MINNICH & McKEE, LLP
Seventh Floor
1100 Superior Avenue
Cleveland
OH
44114-2579
US
|
Assignee: |
STERIS INC., a Delaware
corporation
Temecula
CA
|
Family ID: |
29270710 |
Appl. No.: |
11/401649 |
Filed: |
April 11, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10422474 |
Apr 24, 2003 |
|
|
|
11401649 |
Apr 11, 2006 |
|
|
|
60375851 |
Apr 24, 2002 |
|
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Current U.S.
Class: |
588/299 ;
588/300 |
Current CPC
Class: |
A62D 3/38 20130101; A62D
2101/02 20130101; A61L 2/202 20130101; A61L 2/208 20130101 |
Class at
Publication: |
588/299 ;
588/300 |
International
Class: |
A62D 3/00 20060101
A62D003/00 |
Claims
1-17. (canceled)
18. An apparatus for deactivating biologically active substances
including: a means for subjecting the biologically active
substances in an enclosure to a strong oxidant in a vapor
phase.
19. The apparatus as set forth in claim 18 wherein the biologically
active substances are biological or chemical warfare agents
including one or more of chemical agents, pathogens, prions, and
biotoxins.
20. The apparatus as set forth in claim 19 wherein the chemical
agents include at least one of nerve gas and blistering gas.
21. The apparatus as set forth in claim 18 wherein the oxidant
includes at least one of peroxy compounds, hypochlorates, and
ozone.
22. The apparatus as set forth in claim 21 wherein the peroxy
compounds include hydrogen peroxide.
23. The apparatus as set forth in claim 18 further including: a
means for adding a second chemical in vapor, mist, or fog form to
the enclosure.
24. The apparatus as set forth in claim 23 wherein the second
chemical does at least one of: raises the oxidation potential of
the oxidant vapor rendering the oxidant vapor more reactive against
the biologically active substance; preconditions the biologically
active substance; reacts with the oxidant vapor to generate an
intermediate compound that deactivates at least some of the
biologically active substances; increases a number and variety of
free radical species in the oxidant vapors; and, adjusts pH.
25. An apparatus for deactivating biologically active substances
including at least one of nerve gas, blistering gas, pathogens,
prions, and biotoxins, the apparatus including: a chamber means for
receiving an object that has been contaminated with biologically
active substance and isolating the biologically active substances
from escaping to the ambient atmosphere, the chamber means
including at least one inlet and at least one outlet; filters
mounted to the inlet and the outlet to block the biologically
active substance from exiting the chamber; a source of liquid
oxidant; a vaporizer which vaporizes the liquid oxidant from the
source and supplies the oxidant vapor to the inlet.
26. The apparatus as set forth in claim 25 further including: a
source of a chemical vapor, mist, or fog which at least one of:
raises the oxidation potential of the oxidant vapor rendering the
oxidant vapor more reactive against the biologically active
substance; preconditions the biologically active substance; reacts
with the oxidant vapor to generate an intermediate compound that
deactivates at least some of the biologically active substances;
increases a number and variety of free radical species in the
oxidant vapors; and, adjusts pH.
27. The apparatus as set forth in claim 25 further including: a
source of a chemical vapor, mist, or fog which at least one of:
raises the oxidation potential of the oxidant vapor rendering the
oxidant vapor more reactive against the biologically active
substance; preconditions the biologically active substance; reacts
with the oxidant vapor to generate an intermediate compound that
deactivates at least some of the biologically active substances;
increases a number and variety of free radical species in the
oxidant vapors; and, adjusts pH, the chemical vapor, mist, or fog
source being connected to a second inlet to the chamber means.
28. The apparatus as set forth in claim 25 further including: a
source of a liquid chemical which at least one of: raises the
oxidation potential of the oxidant vapor rendering the oxidant
vapor more reactive against the biologically active substance;
preconditions the biologically active substance; reacts with the
oxidant vapor to generate an intermediate compound that deactivates
at least some of the biologically active substances; increases a
number and variety of free radical species in the oxidant vapors;
and, adjusts pH, the liquid chemical source being connected with
the vaporizer.
29. The apparatus as set forth in claim 18 further including: a
means for supplying ammonia vapor to the enclosure means.
30. The apparatus as set forth in claim 25, wherein the chamber
means preheats the object to about 70.degree. C. to allow
extraction of the biologically active substances from the object to
facilitate reaction between the biologically active substances and
the vaporized oxidant when it is introduced into the chamber means.
Description
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 60/375,851, filed Apr. 24, 2002.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the art of treating
articles with highly reactive oxidant vapors. It finds particular
application in conjunction with deactivating biological and
chemical warfare agents, such as blistering agents (e.g., mustard
gas), acetyl cholinesterase inhibitors (e.g., nerve gas), and
biotoxins (e.g., botulinum toxin) and will be described with
particular reference thereto. However, it is to be appreciated,
that the present invention will find application in conjunction
with the oxidation of other substances.
[0003] Liquid oxidants have been developed which can deactivate
biological warfare agents. See, for example, U.S. Pat. No.
6,245,957 to Wagner, et al. In Wagner, a strong oxidant solution is
sprayed as a liquid or foam onto equipment in the field which is or
has potentially been contaminated with biological and chemical
warfare agents. After treatment, the solution is rinsed from the
equipment with water, which can be permitted to flow onto the
ground, as it is nontoxic. Although effective, the liquid Wagner
solution has drawbacks. First, it is difficult for liquids to
penetrate crevices, fine cracks, ducts, and partially protected or
lapping parts. Second, in enclosed spaces, such as in the interior
of airplanes and buildings, cleanup and disposal of the liquid
solution can be problematic. Third, liquids can damage some
equipment, such as electronic or electrical equipment.
[0004] The present application delivers the strong oxidant to the
surfaces to be decontaminated in a vapor phase to facilitate
penetration and cleanup.
SUMMARY OF THE INVENTION
[0005] In accordance with one aspect of the present invention,
biological and chemical warfare agent residues are deactivated by
oxidation with a vapor phase oxidant.
[0006] In accordance with another aspect of the present invention,
a means is provided for oxidizing biological and chemical warfare
agents with an oxidant vapor.
[0007] One advantage of the present invention resides in its
improved penetration.
[0008] Another advantage of the present invention resides in its
ease of cleanup.
[0009] Another advantage resides in compatibility with electrical
equipment.
[0010] Still further advantages of the present invention will
become apparent to those of ordinary skill in the art upon reading
and understanding the following detailed description of the
preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention may take form in various components and
arrangements of components, and in various steps and arrangements
of steps. The drawings are only for purposes of illustrating a
preferred embodiment and are not to be construed as limiting the
invention.
[0012] FIG. 1 is a diagrammatic illustration of a vapor strong
oxidant treatment system in accordance with the present
invention;
[0013] FIG. 2 is an alternate embodiment of the oxidant vapor
treatment system;
[0014] FIG. 3 is another alternate embodiment of the oxidant vapor
treatment system; and,
[0015] FIG. 4 is yet another alternate embodiment of an oxidant
vapor treatment system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] With reference to FIG. 1, a treatment enclosure 10 receives
or is itself part of the structure potentially contaminated with
biologically active substances such as biological or chemical
warfare agents to be treated with vapor oxidant compounds. Typical
biologically active substances include pathogens, biotoxins,
prions, chemical agents such as nerve gas or blistering agents, and
the like. The treatment enclosure, in one embodiment, is a chamber
that is adapted to receive items to be treated and then sealed. In
another embodiment, the enclosure includes the interior of a
warehouse, room, aircraft or other vehicle, tent, or the like which
is or whose surfaces or items contained in the enclosure are to be
treated.
[0017] A warfare agent oxidizing means A includes a pump 12 that
draws the environmental gas, typically air, from the enclosure
through an optional biological and chemical hazard filter 14 or
other means for preventing contamination in the enclosure from
escaping and preferably through a dryer 16. In a preferred hydrogen
peroxide vapor embodiment, the dryer also includes a catalyst that
breaks down the hydrogen peroxide vapor to water for removal by the
dryer. The blower blows the filtered and dried air into a vaporizer
18, which vaporizes a liquid oxidant compound from a liquid oxidant
supply 20. The vapor is blown through another optional biological
contaminant filter 22 or other means for preventing contamination
in the enclosure from escaping into the chamber 10. Optionally, the
output of the vaporizer is branched or fed to a manifold that feeds
the oxidant vapor into the enclosure from a plurality of locations.
Optionally, additional fans or blowers 24 are placed in the
enclosure to circulate the vapor and improve uniformity of
concentration and distribution of the vapor. The preferred oxidant
liquid includes peroxy compounds such as hydrogen peroxide and
peracetic acid. The use of other oxidants such as hypochlorites,
solutions of ozone, and the like are also contemplated. Optionally,
the oxidant compound is mixed with an alcohol to generate an
alcohol vapor which functions as a cosolvent. When the materials in
the contaminated structure permit, the temperature of the structure
is preferably raised to 70.degree. C. which allows extraction of
the agent from the material and facilitates reaction with the
oxidant vapor. Moreover, higher temperatures permit higher
concentrations of oxidant vapor without condensation problems. Of
course, when plastics or temperature sensitive electronics are
involved, temperatures of 45.degree.-60.degree.C. may be
preferred.
[0018] In the embodiment of FIG. 1, a chemical delivery means
system B delivers other chemistry in a vapor, mist, or fog form
directly into the enclosure 10. The delivery means B includes a
source 42 of other chemical vapor, mist, or fog. In one embodiment,
the other chemistry delivery system includes filters, blowers, and
vaporizers, analogous to those described for the oxidant vapor. In
another embodiment, a liquid chemical is sprayed with a misting
nozzle or fogged with a fogger directly into the enclosure. In yet
another embodiment, a reservoir or cylinder of the other chemical
in gaseous form is provided.
[0019] The other chemistry in one embodiment is selected (1) to
activate the oxidant vapor to a higher oxidation potential, (2) to
increase the number and diversity of reactive species, (3) to
precondition the target substances to make them more susceptible to
attack by the oxidant vapor, or (4) to react with the oxidant vapor
to form an intermediate compound that attacks all or some of the
target substances. In one preferred embodiment, the oxidant vapor
is hydrogen peroxide in a concentration of 25-75%, with about 50%
preferred. In one embodiment, the other chemistry includes short
alkene chains and water vapor, which interacts with the peroxide
vapor to form a number of radical species, such as singlet pairs of
oxygen, methyl radicals (CH.sub.3.sup.-), hydroxyl radicals
(OH.sup.-), hydroperoxy radicals (OOH.sup.-), and others.
Alternately, the other delivery system delivers ozone, aldehydes,
peroxy carboxylic acid, or the like to the chamber in vapor, mist,
or fog. Optionally, UV light sources are used, in addition to or
instead of, the chemical delivery system to enhance the reactive
species.
[0020] In another embodiment, the other chemistry includes a
condensable solvent vapor, mist, or fog that is miscible with water
and produces a solution with reduced polar properties is condensed
on the target substance. Suitable solvents include tertiary butyl
alcohol (tBuOH), formic acid, peracetic acid, other alcohols,
acetone, or acetyl nitrite.
[0021] In another embodiment, the other chemistry adjusts pH. To
lower pH, acetic or formic acid is preferred. Ammonia is preferred
for raising the pH. Typically, strong oxidants have a low pH which
is advantageously raised to near neutral.
[0022] Although only a single other chemistry delivery system is
illustrated in FIG. 1, it is to be appreciated that individual
delivery systems can be provided for the various above-discussed
other chemistries.
[0023] A control 34 controls the other chemistry delivery system or
means B and the peroxy vapor delivery system or means A. In one
embodiment, the peroxy vapor and other chemistry are delivered
concurrently into the enclosure. In another embodiment, the other
chemistry is added to the enclosure first to precondition the
biologically active substances. For example, injecting a cosolvent
vapor and allowing it to condense prior to the hydrogen peroxide
for partially dissolving or otherwise making biologically active
substances that are not soluble in the oxidant vapor more readily
penetrated by the oxidant vapor are contemplated. In another
embodiment, the oxidant vapor is added to the enclosure first to
establish equilibrium and start deactivating the biologically
active substances that are more readily oxidized. Then the other
chemistry is added to boost the reactivity of the oxidant vapor or
to generate an intermediate vapor compound to attack the remaining
biologically active substances.
[0024] With reference to FIG. 2, a blower 12a draws atmospheric air
from an enclosure 10a through a biologically active substance exit
inhibiting means 14a such as a filter or valve and a dryer 16a. The
blower blows the atmospheric gases through a vaporizer 18a that
vaporizes a peroxy liquid, preferably hydrogen peroxide from a
source 20a. The peroxy vapor is passed to a mixing chamber 40a
where the other chemistry delivery means B mixes the peroxy vapor
with the other chemistry from a source 42. In one embodiment, the
mixing chamber 40 adds water vapor and short chain alkene vapor,
aldehyde vapor, peroxycarboxylic acid vapor, or the like, to the
peroxy vapor to form singlet oxygen, hydroperoxy, and other
reactive radicals. In other embodiments, solvents or pH adjusting
compounds are mixed with the oxidant vapor in the mixing chamber
40a. Alternately, the other chemistry reacts with the peroxy vapor
to form an intermediate compound as described above. The modified
vapor is passed through a biologically active substance escape
inhibiting means 22a, such as a filter or check valve, into the
enclosure 10a. The means 14a and 22a prevent contamination in the
enclosure from migrating into the lines of the vapor delivery
system. Optionally, another chemistry delivery system B' delivers a
preconditioning vapor, mist, or fog, ammonia gas, or solvent vapor,
as described above, directly into the enclosure or into the mixing
chamber 40a.
[0025] With reference to the embodiment of FIG. 3, a blower 12b
blows the atmospheric air from an enclosure 10b through a vaporizer
18b of the oxidant vapor means A. The output of the vaporizer is
split between one path 50, which delivers the vapor directly to the
enclosure 10b, and a second path 52 that delivers the vapor through
a mixing chamber 40b of the other chemical delivery means B to the
enclosure 10b. Valves 54, 56 in lines 50 and 52 are controlled by a
control system 34b for dynamically adjusting the proportion of the
oxidant vapor that passes through the mixing chamber to control the
amount of gaseous other chemistry introduced into the chamber.
[0026] With reference to FIG. 4, a blower 12c pulls atmospheric air
through a filter 14c and blows it into a vaporizer 18c. The
vaporizer 18c is connected with an oxidant liquid source 20c and at
least one additional. source of other chemistry 42c. The oxidant
liquid and the other chemistry(ies) are vaporized concurrently or
sequentially in the vaporizer and fed to a treatment enclosure 10c.
Alternately, one or more other chemicals are supplied in gaseous
form and mix in the vaporizer with the oxidant and other chemical
vapors. Air from the treatment enclosure can be recirculated as
described in the first three embodiments. However, in the
illustrated embodiment, the air and vapor pass from the chamber to
an oxidant and other chemistry deactivator 16c such as a catalyst,
and are blown through a biological filter 22c into the atmosphere.
Optionally, the embodiments of FIGS. 1, 2, and 3 can also be
configured in this flowthrough configuration.
[0027] Various chemical reactions for activating the oxidant vapor
to a higher oxidation state are contemplated. Looking to hydrogen
peroxide, by way of example, hydroperoxy ions HOO.sup.- and singlet
oxygen .sup.1O.sub.2 are potent oxidants. Analogous species and
other potent oxidants can be delivered using gas phase delivery. In
its simplest form, when the hydrogen peroxide makes contact with a
surface, it transfers enough energy to the peroxide molecule for it
to decompose into hydroxyl radicals. For example,
H.sub.2O.sub.2+M.fwdarw.2HO.sup.-, where M represents a collision
with the biologically active substance, a wall, other object, other
molecule, or the like. The hydroxyl radicals can go on to form
other more reactive radicals by interactions with hydrogen peroxide
and water vapor. HO.sup.-+H.sub.2O.sub.2.fwdarw.H.sub.2O+HOO.sup.-
HOO.sup.-+HO.sup.-.fwdarw..sup.1O.sub.2+H.sub.2O Hydroxyl radicals
HO.sup.-, hydroperoxy radicals HOO.sup.-, and singlet oxygen
.sup.1O.sub.2 are all potent oxidants and are all present in
hydrogen peroxide vapor to some degree. All of these radicals serve
to inactivate biologically active substances including
acetylcholineesterase inhibitors (VX, sarin, etc.), blistering
agents (mustard gas, etc.), and biotoxins (botulinum toxin, etc.),
biomolecules, pathogens, prions, and other similar biologically
active molecules.
[0028] In addition to the radical generation steps, the hydrogen
peroxide can dissolve or absorb onto/into the biologically active
substance (i.e., dissolve into a liquid droplet, or absorb onto a
solid particle). To enhance this dissolution/absorbtion, a
cosolvent is added to the vapor and allowed to condense onto the
surfaces of the equipment to be decontaminated. The solvent is
selected as good solvents for the biologically active substances.
By selecting a solvent, or solvents, miscible with water (and other
polar solutes like hydrogen peroxide) but with lower polarity, the
cosolvent layer can enhance the solubility of the hydrogen peroxide
and its associated radical decomposition products in the
biologically active substance so enhancing the rate of destruction.
Examples of such cosolvent mixtures include: water and tert-butyl
alcohol; water and acetonitrile; water, acetronitrile and isopropyl
alcohol. By control of the mixture of solvent vapors, and hydrogen
peroxide added to the enclosure, the composition of the condensate
can be controlled to produce a liquid film on the surfaces to be
decontaminated. By adding an alkaline gas soluble in the solvent
mixture (ammonia for example), the pH of the condensed cosolvent
layer can also be controlled. The presence of hydrogen peroxide in
the condensate serves to lower the pH (35% aqueous H.sub.2O.sub.2
solution has a pH of approx. 3-4) and the ammonia can be added to
raise the pH to the optimum value of around 8-9. Other suitable
solvents include tetrahydrofuran, dimethylsulfoxide, acetone,
acetaldehyde, propylene oxide, acetamide, diethylamine, and
dimethoxyethane.
[0029] One way to enhance the generation of reactive radicals is by
irradiating the enclosure with ultraviolet light at a wavelength
that causes degradation of hydrogen peroxide. The increased
degradation increases the concentration of radical intermediaries
and enhances the decontamination effect.
[0030] Adding additional species to the hydrogen peroxide vapor
also enhances the deactivation efficiency by increasing the number
of reactive species present. Enhancing agents include ozone
(O.sub.3), alkenes (CH.sub.3CH.dbd.CHCH.sub.3 or more generally
RCH.dbd.CHR), aldehydes (RCHO), and halogens (Cl.sub.2, Br.sub.2).
For example, the addition of ozone increases the yield of radicals
and the vapor stream. O.sub.3+h.fwdarw.O.sub.2+O* Where atomic
oxygen O* is not a radical (all its electrons have paired spins),
but is highly reactive. O*+H.sub.2O.fwdarw.2HO.sup.-
O*+HOOH.fwdarw.HO.sup.-+HOO.sup.-
[0031] As another example, short chain alkenes are also effective:
RCH.dbd.CHR+O.sub.3.fwdarw.[intermediates].fwdarw.HO.sup.-+HOO.sup.-
This produces radicals from ozone with a higher yield.
[0032] Other molecules, such as aldehydes, result in the presence
of alkyl peroxy radicals: RCHO+HO.sup.-.fwdarw.RCO.sup.-+H.sub.2O
RCO.sup.-+O.sub.2.fwdarw.RC(O)OO.sup.- The product here is the
alkyl peroxy radical, a radical of percarboxylic acid, i.e., if R
is CH.sub.3, this radical is formed from peracetic acid, another
strong oxidant.
[0033] As another example, the addition of peroxycarboxylic acids
(RC(O)OOH) to the reaction enhances the concentration of
alkylperoxy radicals.
[0034] By controlling concentrations of small organic molecules,
such as alkenes, alkanes, aldehydes, carboxylic and peroxy
carboxylic acids, water vapor, hydrogen peroxide, and ozone, a
steady-state concentration of the reactive radicals can be
maintained.
[0035] Halogens are also suitable strong oxidants. Where X is any
halogen: X.sub.2+h.fwdarw.2X.sup.- X.sup.-+HOOH.fwdarw.HX+HOO.sup.-
X.sup.-+tBuOH.fwdarw.HX+tBuO.sup.- Where tBuOH--tert butyl alcohol
is added as part of the cosolvent system.
X.sup.-+H.sub.2O.fwdarw.HX+HO.sup.-
X.sup.-+RCH.sub.3.fwdarw.HX+RCH.sub.2.sup.- It can be seen that
adding appropriate species to the vapor mixture, a wide variety of
radical species can be produced.
[0036] Strong oxidants are effective to attack biomolecules
including proteins, such as anthrax toxin, botulinum toxin, and
plague toxin. Breaking down such toxins into smaller protein chain
fragments renders the toxins harmless. Similarly, reactions in
which the oxidizing radicals break bonds and replace chemical
groups around the phosphorous atom, e.g., a substitution reaction
as in acetylcholine esterase inhibitors render these molecules non
or less toxic. Similarly, oxidation of the sulfoxide or lysis at
one of the sulphide-alkyl bonds renders blistering agent molecules
non or less toxic.
[0037] The invention has been described with reference to the
preferred embodiment. Obviously, modifications and alterations will
occur to others upon reading and understanding the preceding
detailed description. It is intended that the invention be
construed as including all such modifications and alterations
insofar as they come within the scope of the appended claims or the
equivalents thereof.
* * * * *