Patent Application
20090321534
1. Field of the Invention
The invention is directed to a device and a method for generating a vapor and an aerosol from oil. Specifically, the invention is directed to a device and a method for generating a vapor and aerosol that have antimicrobial activity. Further, the invention is directed to a method of decontaminating a space.
2. Description of the Related Art
It is generally known in the art that to produce smoke, a hot gas, usually hot air, is in some way put in contact with a smoke generating fluid. This fluid may be either heated or unheated prior to association with the hot gas. The air heats the smoke generating fluid and vaporizes it while at the same time cooling the air to create the fog or smoke. In this general method, a considerable amount of time is needed for sufficient hot air to heat the smoke fluid to a level to create a substantial amount of vapor. Thus vaporizing smoke builds up slowly in the hot air with a consequent slow build up of fog, smoke or vapor.
In another known method, a pool of smoke generating fluid is heated to a vaporizing temperature, then heated or unheated air is blown through the vapor to create smoke. According to this method, a considerable amount of time is required to heat the fluid to a level for vaporization and there is significant time required for contact between the vapor and air such that the density of the smoke slowly increases then slowly decreases.
In yet another known method, the smoke fluid is atomized and aerosolized directly into a forced air stream. The smoke created by this method is relatively cold and as such has a density greater than air and tends to settle downward rather than rising to fill an area or to provide an effective smoke screen. Another method in the art mixes steam with smoke fluid to vaporize the fluid. The resulting vapors are passed through a confined orifice into the atmosphere where upon cooling of the steam and smoke fluid vapor a smoke is produced.
Smoke oil generators all generally constructed from basically two functional plans; those generators in which the oil fog is generated by atomization of oil particles into the environment simply by compressed air forcing oil through a small nozzle dispersing the oil into a cloud as described in U.S. Pat. Nos. 5,609,798; 4,836,452. In other generators this atomization is enhanced by passing to the oil droplet cloud through a heating plate or block heated by electrical resistance the source of which is supplied by a 12 volt battery as described in U.S. Pat. Nos. 5,922,944 and 6,439,031B1. The most common smoke generator, however, is that in which a smoke oil is heated by an electrical resistance means in a narrow space to above oil vaporization temperature to produce oil droplets which, when cooled either in a chamber means or upon release into the environment, produces an obscuring black or white smoke. Another means of heating the smoke producing oil is to use exhaust gases from a conventional or modified combustion engine operating by the combustion of an air:fuel mixture U.S. Statutory Invention Registration H765 and US patents described following. Nearly without exception these systems produce smoke by release of an oil droplet oil cloud from a high temperature environment into a cooler exterior environment for the purpose of producing an obscurant cloud such as described in U.S. Pat. Nos. 6,400,897B1, 4,419,219 and others described following, for insertion into a system to be examined for leaks such as that described in U.S. Pat. Nos. 5,107,698; 5,859,363; 5,753,800; 4,300,428; or for fire control training by producing a smoke cloud similar to that which might be encountered by a fire fighter as described in U.S. Pat. Nos. 4,349,723; 5,870,524 and others described following.
Other methods of atomization of materials into a defined space include those found in home deodorizers. In these vapor generators oil drawn through a heating source by a wicking apparatus vaporizes and either diffuses into the environment or is accelerated into the environment by a fan apparatus means. These vaporizers can be designed to apply a DC voltage to a wick-like, porous emitter or generator assembly supplied with a liquid to be vaporized. Liquids used in this type of vaporizer can be a disinfectant, an aromatic oil, deodorant, microbicide, including fungicides, bactericides, or insecticides, or a fumigant. These vaporizers can be mounted in a room space or within an HVAC system to facilitate dispersal. Vaporizers of this type are described for example in U.S. Pat. Nos. 5,382,410; 4,136,038; 4,171,340; 6,349,168 B1; 6,773,679. Other vaporizers are those such as described in U.S. Pat. Nos. 4,777,345; 5,991,507; 4,687,904; and 4,731,522.
The inventors have developed an improved device (generator) and method for generating oil vapor and/or oil aerosol. The generator and method combine the generation of oil aerosol and vapor generation using heat and compression with a condenser and filter system to control the aerosol particle size or to eliminate aerosols from generated vapor. Also unique is the utilization of this generator and method for the purpose of producing an aerosol or gaseous vapor disinfectant derived preferably from plant oil, preferably soybean oil, or methylated derivatives of plant oils such as methyl soyate for example.
The generator functions to heat a smoke oil source be it a plant oil, methyl derivatives thereof, a petroleum oil, diesel oil, oil derived from animal fat or any other oil or methyl derivatives or any other structural derivatives of oils such as these to its vaporization point. The generator is designed to remove any non-vaporized oil from the resulting smoke via a condensing trap, filter the smoke to remove all but the desired size oil particles or all oil products such that a gas vapor is released to produce obscurant smoke and/or to produce an aerosol or gaseous vapor. This vapor or aerosol can be used to disinfect small and large spaces contaminated with microorganisms including but not exclusive of virus, virus particles, bacteria, bacterial spores, fungi and fungal spores and yeasts. The spaces to be disinfected include but are not exclusive of, commercial and military aircraft and vehicles used to transport materials, foodstuffs, personnel and any other items that are commonly carried by these means, military installations including among other spaces, barracks, offices, hospitals, storage facilities, vehicles, and laboratories used for medical or research and development; agricultural production systems; post office mail stream; historic artifacts including those of cellulose, lignin, collagen, keratin, or chitin composition; spaces housing these artifacts including museums, archeological digs, vaults, warehouses, libraries among others. Also of value to disinfect with the technology previously disclosed using the generator disclosed herein are passenger and cargo ships, truck trailers and train cars, hospital rooms, hospice and controlled residential facilities such as day care centers, nursing homes and extensions thereof, long- short- and intermediate-term care facilities, and prisons and jails. This technology could be adopted by NASA for decontamination of their facilities and vehicles and by other governmental agencies for use as needed.
In agricultural the production of eggs or chickens or of dairy or beef cattle and other live stock for market leads to contamination of the production facilities and eventually the products produced in these facilities with organisms such as E. coli O157H, Salmonella spp., Campylobacter spp., Listeria spp, and other enteric bacteria which when incorporated into the food chair become food borne emerging pathogens. Anthrax is a common contaminant in cattle and dairy production. The technology and generator can be used to “clean” these areas making it safe for workers employed in the contaminated areas and for the public who purchase the products for consumption. Legionella is often a contaminant of HVAC systems and infection by this pathogen of immuno compromised individuals can lead to death. The generator could be used to move an effective disinfectant into and through HVAC systems. An example of probable use would be to decontaminate U.S. Senate office building offices exposed to Bacillus anthracis. Another example is decontamination of chicken raising facilities of Salmonella and other bacterial facilities or of livestock rearing areas and slaughter houses of bacteria associated with production. Still other examples might be the use in decontaminating aircraft between passenger flights. Cruise ships recently have been the source of bacterial infections leading to wide spread sickness amongst the travelers; this is yet another potential use. Artifact materials are destroyed by bacteria and fungi thus a potential use would be in the routine decontamination of museums, libraries and archives housing these materials or of these materials recovered on archeological dig sites. These are but a few examples for potential use and other uses of this generator and the associated disinfectant technology are limited only by one's imagination.
The invention described is that of a generator for production of a oil based aerosol or a gaseous vapor generated there from to be used for decontamination of spaces and areas, including but not exclusive of, rooms, laboratories, cargo carriers, air craft, HVAC systems, historic artifacts and documents, agricultural production facilities, hospital facilities, office spaces, and all other areas or facilities accessible to the apparatus as described for microorganisms including but not exclusive of viruses and viral particles, bacteria, bacterial spores, fungi, and fungal spores and yeasts. The generator is capable of producing either an aerosol or a gaseous vapor developed from the aerosol by heating petroleum fuels, plant oils, animal fat derived oils, or light mineral oils in the temperature range of from 250° C. to 800° C. with a tolerance of ±5° C. The generator is capable of producing oil particles of any size within the range of 0.04 microns to approximately 3 microns in diameter with the most preferred size being in the range of approximately 0.15 microns to 1.5 microns in diameter. The addition of a unique condensing trap means into the stream of smoke movement immediately after the thermostat-controlled (thermostated) concentric tubular oven used to heat the producing oil source allows removal of excess non vaporized oil particles from the smoke to produce a gaseous vapor capable of the desired decontamination effectiveness and with the enhanced advantage of leaving no residue following the decontamination process. A filter apparatus means placed in the vapor flow stream controls the size of fog oil particles released or removes all residual non-vaporized fog oil from being released into the environment.
Oil flow rate in the generator is optimal in the range of approximately 0.02 milliter per minute to 10.5 ml per min with a flow rate of at least 0.1 ml per min. Air flow rate into the condenser for the purpose of moving the aerosol smoke through the transfer tubes into the particle size filters and through the exhaust port into the atmosphere is at a minimum of 3 Liters per minute in a laboratory sized generator as shown in
The preferred oil for generation of a disinfectant aerosol or gaseous vapor is a plant oil including but not exclusive of soybean oil, corn oil, sunflower seed oil, rape seed oil, or linseed oil and the methyl esters thereof, petroleum oil including diesel fuel such as, but not exclusive of, JP4, JP8, MOGAS or other petroleum based oils, light mineral oil, or oils derived from animal fat and the methyl esters thereof.
The disclosed apparatus as shown in
In a laboratory sized generator the vapor/aerosol producing oil is flowed into the tubular furnace means at a constant rate of from 0.1 ml/min to 100 ml/min; flow rate is dependent on the size of the generator and can be increased 100 to 1000 fold over that in the laboratory sized generator as needed for the preferred embodiment. The thermostat controlled concentric tubular furnace is heated by an electric resistance means and is controlled in the range of 250° C. to 800° C. depending on the type of oil and the desired result of vaporization. A compressed air stream generated from an air compressor means is used to force the vaporized oil as a smoke out of the furnace means through a delivery tube (a.k.a. transport tube), passing over a oil condensate collector means either external to, or included in, a size selective screen filter chamber means containing filter means (e.g., cold trap condenser and the to select the size oil droplets exhausted or to remove all oil droplets from the smoke allowing only a gaseous vapor to be emitted from the generator. A glass lined chamber fitted with sampling ports can be inserted between the filter means and the exhaust means for the purpose of sampling the exhausted material for particle size, chemical composition and/or toxicity (
In the preferred embodiment of the invention a smoke containing oil particle size from approximately 0.04 microns in diameter to approximately 2 microns in diameter is produced for release into the environment for effective decontamination of microorganisms including, but not exclusive of, virus and viral particles, bacteria, bacterial spores, fungi, fungal spores and yeasts. In a more preferred embodiment oil particles are produced in the size range of 0.15 microns in diameter to 1.5 microns in diameter. In the most preferred embodiment only a gaseous vapor from which all oil particles have been removed into the oil condenser means and/or by the filter chamber means is released into the environment as a microbial decontaminant (
Several parameters of the generator herein described are controlled to maximize aerosol or gaseous vapor generation for the intended purposes dependent on oil type, desired oil flow rate, generation temperature and exhausted product. In the preferred embodiment the oil flow rate is controlled from a dual piston pump means at from 0.1 ml per minute to 10.0 ml per minute through a thermostat controlled concentric tubular heated by electrical resistance means and controlled over a temperature range of from 350° C. to 650° C. (±5° C.). In the most preferred embodiment the oil flow rate is adjusted to provide maximally effective volume of vapor required to decontaminate the area defined by use. These areas include but are not inclusive of agricultural production facilities, food production facility, poultry rearing facility, cattle or swine rearing or producing facility, bioweapons manufacturing facility, feed lot, slaughter house, sewage treatment plant, hospital, health clinic, battle field, ballast tank of ships, cabins of airplanes, hospital rooms including laboratories and surgery theaters, kitchen, mail handling facility, border crossing facility, school, office space, class rooms, research laboratories, meeting halls private homes, public arenas, theaters, performance halls or the like, private facilities and commercial facilities and the like. In the most favored embodiment the entire generator means is enclosed in an insulated metal encasement for easy safe transport and use.
The following Example describes the use of the smoke generator described herein to decontaminate areas contaminated with bacteria and bacterial spores.
The most preferred embodiment of the smoke generator is as a means to produce a non-aerosol vapor for use in decontamination of commercial, public and private spaces of viral particles, bacteria and bacterial spores, fungi and fungal spores as detailed in US patent application (Production and Use of a Gaseous Vapor or Aerosol Product from Plant Oils or Light Oils as an Environmental Disinfectant). In this example methyl soyate was heated to above its vapor temperature and vaporized. The resulting “fog” was passed through the filter screen of the smoke generator means and exhausted into a chamber containing culture plates inoculated with several bacterial species. The material entering the chamber was a clear vapor which leaves no residue but is effective in decontaminating the chamber.
Fog oil and methyl soyate aerosols were tested for their toxicity toward various microbes. The oil aerosols used in this study were generated through a process that mimics the operation of a “fog oil smoke” generator used by the U.S. Army. The process involves volatilization and subsequent condensation of fog oils and soy oil esters yielding particles of approximately 0.5-1 micron in diameter, which are effective obscurants for visible light and stabile in ambient air for up to 30 minutes.
Plates containing enriched nutrient minimal agar (MNA) media were inoculated with Salmonella strains, placed into an exposure chamber, and exposed to fog oil or methyl soyate smokes for a duration ranging from approximately 30 seconds to 2 minutes. The smokes (oil aerosols) were generated by introducing 0.5 mL min−1 of oil into a stainless steel tube maintained at 350° C. Controls were plates containing MNA media that were placed in an exposure chamber for 30 minutes in the absence of exposure to oil aerosol. After exposure all plates were incubated at 37° C. for 24 hours and examined for the presence of Salmonella colonies. Examination of the MNA plates exposed to aerosols for various intervals of time showed that Salmonella colonies were present only on plates that were exposed to oil aerosol for less than 2 minutes. No colonies were observed on those plates that were exposed for longer time intervals, demonstrating that oil aerosol exhibits high toxicity towards Salmonella.
In a variation of the above experiment, MNA plates were covered with ordinary paper or paper tissues and exposed to oil aerosol (fog oil or methyl soyate) for 2 minutes or 5 minutes. The plates were removed from the chamber, inoculated with the bacterial cultures, incubated for 24 hours, and examined for the presence of bacterial colonies. No colonies grew, demonstrating that the microbicidal agent found in oil aerosols is able to penetrate paper while maintaining its effectiveness as a microbicide. In a variation of this paper experiment, examination of paper and paper tissue exposed to oil aerosol prior to inoculation plates gave results similar to those obtained with direct exposure plates. No Salmonella colonies were observed on plates exposed for intervals longer than two minutes. This result indicates that a microbicidal agent produced during aerosol generation of fog oil or methyl soyate readily diffuses through paper or wipe tissue, gets incorporated into the agar matrix, and makes the agar unfit for microbial growth.
In yet another variation of the above experiment, MNA plates were exposed to oil aerosols (fog oil or methyl soyate) and, after removal from the chamber, placed in a sterile hood for a period of from 5 to 30 minutes. The plates were then inoculated with the bacterial culture, incubated for 24 hours, and examined for the presence of bacterial colonies. Examination of plates exposed to oil aerosol prior to inoculation gave results similar to those obtained with direct exposure plates. No Salmonella colonies were observed on plates exposed for intervals longer than two minutes. This result demonstrates that the microbicidal agent produced during oil aerosol generation is incorporated into the agar matrix and makes agar unfit for bacterial growth.
To assess the toxicity of fog oil and methyl soyate aerosol toward a wider range of microbial strains, additional exposure experiments were carried out. The exposure experiments were repeated with MNA plates that were preinoculated with the organisms listed in Table 1 and exposed to fog oil and methyl soyate “smokes” for 2 minutes. After the exposure the plates were incubated for 48 hours at 37° C. and examined for the presence of microbial colonies. The results are summarized in Table 1. A plus sign (+) signifies microbial growth. A minus sign (−) signifies no growth or microbial death. No microbial colonies were observed in any of the plates exposed to the fog oil smoke, whereas some colonies were observed on Pseudomonas aeruginose plates exposed to methyl soyate aerosols.
Salmonella typhimurium
Klebsiella pneumonia
Escherichia coli 25922
Pseudomonas aeruginosa
Enterobacter cloacae
Serratia marcescens
