CA2249924A1 - Method and portable apparatus for improving indoor air quality by means of ultraviolet radiation sterilization - Google Patents
Method and portable apparatus for improving indoor air quality by means of ultraviolet radiation sterilization Download PDFInfo
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- CA2249924A1 CA2249924A1 CA 2249924 CA2249924A CA2249924A1 CA 2249924 A1 CA2249924 A1 CA 2249924A1 CA 2249924 CA2249924 CA 2249924 CA 2249924 A CA2249924 A CA 2249924A CA 2249924 A1 CA2249924 A1 CA 2249924A1
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- radiation
- air
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- radiation chambers
- indoor air
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L9/00—Disinfection, sterilisation or deodorisation of air
- A61L9/16—Disinfection, sterilisation or deodorisation of air using physical phenomena
- A61L9/18—Radiation
- A61L9/20—Ultra-violet radiation
Abstract
The present invention relates to a portable air sterilization apparatus which comprises a germicidal unit having a plurality of radiation chambers mounted therein; a source of UV radiation mounted within the chambers for destroying bacteria and viruses contained within the air; blower means for drawing air into the radiation chambers, and outlet means for emitting irradiated air from the radiation chambers and into the environment.
Description
METHOD AND PORTABLE APPARATUS FOR IMPROVING INDOOR AIR
QUALITY BY MEANS OF ULTRAVIOLET RADIATION STERILIZATION
Field of the Invention The present invention relates in general to engineering solutions to Indoor Air Quality (IAQ) problems and more specifically to low and high intensity ultraviolet radiation sources for sterilization and purification of indoor air for residential, commercial and industrial use.
Background of the Invention Air in homes, schools, offices and other non-residential buildings contains solvents, chemicals, gases, smoke, bacteria, viruses and other pollutants.
The findings from approximately eight hundred and thirty building investigations in the USA and Canada agree with the review of building-related illnesses by the Health and Welfare Canada, an organization engaged in a health hazard evaluation program that now includes the Indoor Air Quality Problem.
If needs for comfort, health, and well being are not satisfied, building users may begin to complain of symptoms which are associated with poor IAQ. "Sick building syndrome" (SBS) is now a common term in the workplace and a building 2 0 owner's nightmare.
The United States Environmental Protection Agency (EPA) has estimated that the United States spends over $1 Billion in direct medical costs attributable to IAQ
problems. "Sick" buildings are costly for a number of reasons. Productivity is decreased and absenteeism rates are elevated. The EPA's latest estimate is that $60 2 5 billion lost annually in decreased productivity brought about by poor IAQ.
The national cost associated with lost productivity from non-IAQ-related major illnesses is estimated at $4.7 to $5.4 billion annually.
The human carrier is a major source of epidemic diseases through transmission from one person to another of organic matter contained in viable airborne particulates, 3 0 which may be bacterial, viral or fungal. Public buildings, schools, theaters, aircraft and other public transportation enclosures are areas from which contaminated atmospheres are likely to be inspired. Individuals leaving such areas may carry pathogenic organisms in their respiratory passages as well as on their clothing. In addition, a human being may be a source of infectious organisms, as well as a carrier, 3 5 notably of the several species and strains of the genus staphylococcus, and it is doubtful that this pathogen will ever be eliminated from human environment.
A special case is in the food industry which involves the manufacture, handling and preservation of food. In such an environment living microorganisms are generated by a spoiling food. Modern techniques and standards in operations involving food handling and the manufacture of many products require a clean air environment. Elaborate and expensive equipment is available to produce clean air, but the cost and inconvenience of installation is prohibitive in many instances, where the demand for cleanliness is the greatest. The efficiency and effectiveness of the available equipment leaves much to be desired and discourages use where the equipment might otherwise be employed.
It is particularly important in food handling environments to reduce airborne microorganisms. Contamination and spoilage of meats and other perishable food products cause large wastage and produce consumer dissatisfaction. The reduction of airborne microorganisms and maintenance of these microorganisms at acceptable levels extends the shelf life of perishable products and assures the consumer a quality product.
The need for the asepsis of environmental air in food and pharmaceutical manufacturing areas, hospitals, clinics, nurseries and civil defense shelters has long been recognized, and many air purification devices and systems utilizing ultraviolet radiation have been heretofore described. Ultraviolet radiation has long been recognized as useful for killing various types of microorganisms and particularly bacteria and viruses. It has been used in rooms for providing a more sterile 2 0 atmosphere to increase the useful life of spoilable product and has been used in hospitals to prevent or minimize the transfer of microorganisms through the air.
Ultraviolet rays not only destroy airborne bacteria, viruses and microorganisms but they also have the potential for effective destruction of volatile organic compounds and hazardous air pollutants.
2 5 When organic compounds absorb ultraviolet light energy, they are activated and they may decompose (photodissociation) or react with other compounds (radical oxidation). Such treated air is beneficial in deep-seated localized infections, sluggishly healing wounds, sinuses, chronic ulcers, burns, almost all skin infections, simple anemia and conditions which disturb metabolism.
3 0 The problems listed above confirm the benefit of utilizing ultraviolet radiation in improving the Indoor Air Quality.
Numerous patents exist on methods and equipment for the cleaning and sterilization of air using ultraviolet radiation sources, but few effective devices currently exist. There is no demand on the existing equipment.
3 5 Various efforts include US 3,518,046 issued June 1970 to Cicirello, US
3,757,495 issued December 1971 to Stevens, US 4,017,736 issued April 1977 to Ross, CA 1,161,741 to Haluk, CA 1,147,526 to Kodera and CA 1,182,143 to Kulin.
In order to develop effective and easy to use equipment for sterilizing air those skilled in the art realize that it is necessary to combine the knowledge of radiation and matter, spectroscopy, biochemistry, biophysics, gas-dynamics and heat transfer and designing.
The use of relatively unknown physical or chemical effects may lead to dangerous consequences to human health such as for example, the development of mutant microbes which may dwell in buildings.
It is known that sterilization is an act of destroying all forms of life on and in an object. A substance is sterile, from a microbiological point of view, when it is free of all living microorganisms. Regardless of the manner in which microorganisms are killed, they generally die at a constant rate under specified environmental conditions.
If the logarithm of the number of survivors is plotted against time, the resulting curve is a straight line. It follows, that special conditions are required, such as the most sensitive wave-lengths in the neighborhood of 265 nm, the ultraviolet radiation energy and time of medium treatment (particularly air) at which microorganisms are killed and the production of mutants in yeast is averted (Table 1 ) r- o o~
H
c i o killing I
o mutant production 0.5 I
I
I
240 260 ,265 280 300 wavelength, nm Table 1: _ Action spectra for the killing ofybast and the production of mutants in yeast by radiation with ultraviolet light. (ARer C. Raut and W. L Simpson, Aroh. 9iochem. Blophys., 57(1):278-?28, 19551 United States Patent No. 3,518,046 issued to Daniel J. Cicirello on June 30, 1970 discloses a method and apparatus for the destruction of airborne microorganisms within a room which utilizes ultraviolet lamps. The environmental air circulates through an upright tube having a height slightly less than the height of the room, the tube containing a pair of coextensive germicidal radiators effective to destroy airborne pathogenic microorganisms passing there along. Room air is discharged from each end of the tube after being taken into the tube through an intake located at about one-half of the height of the room. The stratum of air at this elevation has the densest population of viable airborne particulate.
The disadvantages of this invention are: stationary placement, very low output and a prerequisite that "... complete sterilization of the air on its first pass through the apparatus is not a critical matter, for the reason that the room air will in any event become sterile as it is continuously circulated through the sterilizing zones within the tube". Any microbes which still survive after the first cycle of going through the apparatus can adapt and mutate.
U.S. Patent No. 3,757,495 issued to William E. Sievers on December 30, 1971 discloses a portable air purifier for recycling room air to remove contaminants and solids such as dust, pollen and lint by a filtering operation. Microorganisms such as bacteria and viruses are destroyed by exposure to the ultraviolet light radiation. The 2 0 sterilizing device of the air purifier has two passageway-defining assemblies.
However, the sterilizing device is not suitable for use since the device requires "at least one first and second passageway-defining assembly in said cabinet in communication with said air discharge through which air after passing through said first and second filter flows at a velocity of between 700 to 1100 feet per second in 2 5 opposite directions, with each of said first and second passageways being at least 3 feet in length, and each of said passageways having a transverse cross section of between 9 and 16 square inches, with air after traversing said first and second passageways discharging into the interior of said cabinet to subsequently be returned to said room by discharging through said air outlet". The patent discloses that the 30 impact on the microorganisms in the apparatus (i.e. the residence time of microorganisms are in the apparatus) is equal to 0.0085 second when the velocity is 700 feet per second, and 0.0055 second when the velocity is 1,100 feet per second.
Therefore, only low intensity ultraviolet lamps can be used in the described design. It is a known fact that the apparatus requires an exposure time of approximately 3 5 seconds.
U.S. Patent No. 4,017,736 issued to Henry K. Ross on April 12, 1977 discloses an air purification system utilizing ultraviolet radiation. The system utilizes a pre-filter metal mesh and sub-micron laminar flow cell to remove particles and a high intensity ultraviolet generator to kill microorganisms as air is forced by fan means through a shielded enclosure. A portable air purification system uses ultraviolet radiation and comprises fan means mounted within an upstanding elongated metallic enclosure, a plurality of high intensity ultraviolet tubes vertically mounted within said enclosure in position to expose all air passing therethrough to ultraviolet radiation. The system has 12 high intensity ultraviolet tubes and only one low-efficient fan.
There was therefore a need to develop an apparatus and method for sterilizing air that obviates the problems encountered with the known systems of the prior art.
Summary of the Invention It is an aspect of the invention to provide an improved sterilizing apparatus for both residential and commercial use.
The invention provides a sterilizing apparatus that is simple in construction, economical to manufacture and efficient to use in that it can effectively destroy contaminants in the air.
In accordance with an aspect of the present invention is a portable air sterilization system which comprises an elongated hollow plastic enclosure containing a prefabricated germicidal unit which is cast under pressure from aluminum.
The unit 2 0 has radiation chambers mounted in the longitudinal and transverse directions.
Ultraviolet radiation low-pressure mercury vapor lamps are mounted inside these radiation chambers. A blower means is positioned within the enclosure to draw air downward from the top of the apparatus through the air gap extending around the periphery of the enclosure. As the air enters the enclosure, it passes through the 2 5 radiation chambers and comes out of the bottom partition.
According to an aspect of the present invention is a portable air sterilization apparatus comprising:
a germicidal unit having a plurality of radiation chambers mounted therein;
a source of UV radiation mounted within said chambers for destroying 3 0 bacteria and viruses contained within said air;
blower means for drawing air into said radiation chambers, and outlet means for emitting irradiated air from said radiation chambers and into the environment.
Yet another aspect of the present invention is to provide a method for 3 5 sterilizing indoor air, the method comprising:
drawing indoor air containing bacteria and viruses through a plurality of zigzag passageways;
irradiating said indoor air; and emitting said irradiated air from said radiation chambers and into the environment.
Brief Description of the Detailed Drawings A preferred embodiment of this invention is illustrated in the accompanying drawings, in which like numerals denote like parts throughout, and in which:
Figure 1 is a side cross-sectional view of the apparatus in accordance with an embodiment of the present invention;
Figure 2 is a cross sectional view of the apparatus taken on line A - A of Figure 1;
Figure 3 is a longitudinal cross sectional view taken on lines II - II and III
- III
of Figure 2; and Figure 4 is a longitudinal cross sectional view of the apparatus taken on line IV - IV of Figure 2.
In the drawings, preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood that the description and drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.
Description of the Preferred Embodiment The invention will be readily understood by referring to Figures 1 - 4 in which the portable apparatus of the present invention is shown and referred to as numeral 1.
The portable apparatus 1 is designed to roll about on casters 2. An elongated 2 5 cylindrical plastic enclosure 3 includes top and bottom partitions 4 and 5 and a cap member 6. A plurality of ultraviolet tubes 7 is mounted vertically inside radiation chambers 8-16 and tube ballasts are mounted between top and bottom partitions 4 and 5. Blower means 17 are positioned within enclosure 3 to draw air downward from the top of the apparatus through air gap 18 extending around the periphery of enclosure 3.
3 0 The blower means may be any suitable type of fan which is powered electrically or by gas. One skilled in the art would readily comprehend the types of fans that could be used in the apparatus of the present invention. As the air enters the enclosure 3, it passes through radiation passageways 100 (radiation chambers 8-9-10), 102 (radiation chambers 13-12-11) and 104 (radiation chambers 14-15-16) and comes out of the 3 5 bottom partition S. The passageways 100, 102 and 104 include openings 19 -properly positioned butt plugs 25-36. An example of a path of air in passageway 102 is shown in Figure 1. The air follows the direction of the arrows once is has entered the enclosure 3. The air flows down chamber 13 until it reaches the bottom of the chamber. The butt plug 32 blocks the air from exiting the chamber and the air goes through the opening 21 to chamber 12. Due to the butt plug 31, the air flows upwards until it reaches the top of chamber 12. The butt plug 30 stops the flow of air upwards and the air flows through opening 22. Butt plug 29 causes the air to flow downward until it exits at the bottom of chamber 11. This is repeated in the other two passageways 100 and 104. All three passageways taken together form a prefabricated germicidal unit 37, which is cast under pressure from aluminum. The wall thickness of the radiation chambers is from 1.5 to 2.0 mm and this can vary depending on the size of the apparatus. The inside surface of the radiation chambers is smooth so that ultraviolet light from the lamps is reflected back and forth in the passageways in a criss-cross pattern. Thus, microorganisms and viruses entrained with the air flowing through passageways 100, 102 and 104 are accordingly subjected to maximum contact with the ultraviolet light to such extent that substantially all such microorganisms and viruses are killed.
In order to ensure even air distribution in enclosure 3, the air is discharged from blower 17 to radiation chambers 8, 13 and 14 and comes out of the radiation chambers 10, 11 and 16. Thus, every air passageway includes three radiation chambers.
In low intensity ultraviolet radiation lamps, with the most sensitive 2 0 wavelengths in the neighborhood of 265 NM, the maximum distance between the walls of the ultraviolet tube and the radiation chamber should not exceed 32 mm and the exposure time should not be less than 4 sec. Thus, velocity of the airflow in the passageway is a function of the number of radiation chambers in one passageway and their height (which is equal to the height of the ultraviolet tubes). The number of passageways in the prefabricated germicidal unit 37 effects the processed air capacity of the apparatus only.
Design data for the invention is presented in table 2.
The present invention uses the upper air intake located at about half of the room height, the air stratum at this elevation has the densest population of viable 3 0 airborne particulates.
It is evident from Table 2 that it is possible to achieve the satisfactory output using this invention which has heretofore not been achieved for the portable residential apparatus. Therefore, the method and apparatus of this invention may be readily used as a means of indoor air sterilization in the rooms with a living space of 3 5 about 25-75m in a relatively short period of time.
One skilled in the art understands that the apparatus can be designed to be both portable and stationary. It can also be designed of varying sizes, so long as the operating configurations are maintained such that the apparatus effectively destroys air-borne contaminants.
Although preferred embodiments have been described herein in detail, it is understood by those skilled in the art that variations may be made thereto without departing from the scope of the invention or the spirit of the appended claims.
QUALITY BY MEANS OF ULTRAVIOLET RADIATION STERILIZATION
Field of the Invention The present invention relates in general to engineering solutions to Indoor Air Quality (IAQ) problems and more specifically to low and high intensity ultraviolet radiation sources for sterilization and purification of indoor air for residential, commercial and industrial use.
Background of the Invention Air in homes, schools, offices and other non-residential buildings contains solvents, chemicals, gases, smoke, bacteria, viruses and other pollutants.
The findings from approximately eight hundred and thirty building investigations in the USA and Canada agree with the review of building-related illnesses by the Health and Welfare Canada, an organization engaged in a health hazard evaluation program that now includes the Indoor Air Quality Problem.
If needs for comfort, health, and well being are not satisfied, building users may begin to complain of symptoms which are associated with poor IAQ. "Sick building syndrome" (SBS) is now a common term in the workplace and a building 2 0 owner's nightmare.
The United States Environmental Protection Agency (EPA) has estimated that the United States spends over $1 Billion in direct medical costs attributable to IAQ
problems. "Sick" buildings are costly for a number of reasons. Productivity is decreased and absenteeism rates are elevated. The EPA's latest estimate is that $60 2 5 billion lost annually in decreased productivity brought about by poor IAQ.
The national cost associated with lost productivity from non-IAQ-related major illnesses is estimated at $4.7 to $5.4 billion annually.
The human carrier is a major source of epidemic diseases through transmission from one person to another of organic matter contained in viable airborne particulates, 3 0 which may be bacterial, viral or fungal. Public buildings, schools, theaters, aircraft and other public transportation enclosures are areas from which contaminated atmospheres are likely to be inspired. Individuals leaving such areas may carry pathogenic organisms in their respiratory passages as well as on their clothing. In addition, a human being may be a source of infectious organisms, as well as a carrier, 3 5 notably of the several species and strains of the genus staphylococcus, and it is doubtful that this pathogen will ever be eliminated from human environment.
A special case is in the food industry which involves the manufacture, handling and preservation of food. In such an environment living microorganisms are generated by a spoiling food. Modern techniques and standards in operations involving food handling and the manufacture of many products require a clean air environment. Elaborate and expensive equipment is available to produce clean air, but the cost and inconvenience of installation is prohibitive in many instances, where the demand for cleanliness is the greatest. The efficiency and effectiveness of the available equipment leaves much to be desired and discourages use where the equipment might otherwise be employed.
It is particularly important in food handling environments to reduce airborne microorganisms. Contamination and spoilage of meats and other perishable food products cause large wastage and produce consumer dissatisfaction. The reduction of airborne microorganisms and maintenance of these microorganisms at acceptable levels extends the shelf life of perishable products and assures the consumer a quality product.
The need for the asepsis of environmental air in food and pharmaceutical manufacturing areas, hospitals, clinics, nurseries and civil defense shelters has long been recognized, and many air purification devices and systems utilizing ultraviolet radiation have been heretofore described. Ultraviolet radiation has long been recognized as useful for killing various types of microorganisms and particularly bacteria and viruses. It has been used in rooms for providing a more sterile 2 0 atmosphere to increase the useful life of spoilable product and has been used in hospitals to prevent or minimize the transfer of microorganisms through the air.
Ultraviolet rays not only destroy airborne bacteria, viruses and microorganisms but they also have the potential for effective destruction of volatile organic compounds and hazardous air pollutants.
2 5 When organic compounds absorb ultraviolet light energy, they are activated and they may decompose (photodissociation) or react with other compounds (radical oxidation). Such treated air is beneficial in deep-seated localized infections, sluggishly healing wounds, sinuses, chronic ulcers, burns, almost all skin infections, simple anemia and conditions which disturb metabolism.
3 0 The problems listed above confirm the benefit of utilizing ultraviolet radiation in improving the Indoor Air Quality.
Numerous patents exist on methods and equipment for the cleaning and sterilization of air using ultraviolet radiation sources, but few effective devices currently exist. There is no demand on the existing equipment.
3 5 Various efforts include US 3,518,046 issued June 1970 to Cicirello, US
3,757,495 issued December 1971 to Stevens, US 4,017,736 issued April 1977 to Ross, CA 1,161,741 to Haluk, CA 1,147,526 to Kodera and CA 1,182,143 to Kulin.
In order to develop effective and easy to use equipment for sterilizing air those skilled in the art realize that it is necessary to combine the knowledge of radiation and matter, spectroscopy, biochemistry, biophysics, gas-dynamics and heat transfer and designing.
The use of relatively unknown physical or chemical effects may lead to dangerous consequences to human health such as for example, the development of mutant microbes which may dwell in buildings.
It is known that sterilization is an act of destroying all forms of life on and in an object. A substance is sterile, from a microbiological point of view, when it is free of all living microorganisms. Regardless of the manner in which microorganisms are killed, they generally die at a constant rate under specified environmental conditions.
If the logarithm of the number of survivors is plotted against time, the resulting curve is a straight line. It follows, that special conditions are required, such as the most sensitive wave-lengths in the neighborhood of 265 nm, the ultraviolet radiation energy and time of medium treatment (particularly air) at which microorganisms are killed and the production of mutants in yeast is averted (Table 1 ) r- o o~
H
c i o killing I
o mutant production 0.5 I
I
I
240 260 ,265 280 300 wavelength, nm Table 1: _ Action spectra for the killing ofybast and the production of mutants in yeast by radiation with ultraviolet light. (ARer C. Raut and W. L Simpson, Aroh. 9iochem. Blophys., 57(1):278-?28, 19551 United States Patent No. 3,518,046 issued to Daniel J. Cicirello on June 30, 1970 discloses a method and apparatus for the destruction of airborne microorganisms within a room which utilizes ultraviolet lamps. The environmental air circulates through an upright tube having a height slightly less than the height of the room, the tube containing a pair of coextensive germicidal radiators effective to destroy airborne pathogenic microorganisms passing there along. Room air is discharged from each end of the tube after being taken into the tube through an intake located at about one-half of the height of the room. The stratum of air at this elevation has the densest population of viable airborne particulate.
The disadvantages of this invention are: stationary placement, very low output and a prerequisite that "... complete sterilization of the air on its first pass through the apparatus is not a critical matter, for the reason that the room air will in any event become sterile as it is continuously circulated through the sterilizing zones within the tube". Any microbes which still survive after the first cycle of going through the apparatus can adapt and mutate.
U.S. Patent No. 3,757,495 issued to William E. Sievers on December 30, 1971 discloses a portable air purifier for recycling room air to remove contaminants and solids such as dust, pollen and lint by a filtering operation. Microorganisms such as bacteria and viruses are destroyed by exposure to the ultraviolet light radiation. The 2 0 sterilizing device of the air purifier has two passageway-defining assemblies.
However, the sterilizing device is not suitable for use since the device requires "at least one first and second passageway-defining assembly in said cabinet in communication with said air discharge through which air after passing through said first and second filter flows at a velocity of between 700 to 1100 feet per second in 2 5 opposite directions, with each of said first and second passageways being at least 3 feet in length, and each of said passageways having a transverse cross section of between 9 and 16 square inches, with air after traversing said first and second passageways discharging into the interior of said cabinet to subsequently be returned to said room by discharging through said air outlet". The patent discloses that the 30 impact on the microorganisms in the apparatus (i.e. the residence time of microorganisms are in the apparatus) is equal to 0.0085 second when the velocity is 700 feet per second, and 0.0055 second when the velocity is 1,100 feet per second.
Therefore, only low intensity ultraviolet lamps can be used in the described design. It is a known fact that the apparatus requires an exposure time of approximately 3 5 seconds.
U.S. Patent No. 4,017,736 issued to Henry K. Ross on April 12, 1977 discloses an air purification system utilizing ultraviolet radiation. The system utilizes a pre-filter metal mesh and sub-micron laminar flow cell to remove particles and a high intensity ultraviolet generator to kill microorganisms as air is forced by fan means through a shielded enclosure. A portable air purification system uses ultraviolet radiation and comprises fan means mounted within an upstanding elongated metallic enclosure, a plurality of high intensity ultraviolet tubes vertically mounted within said enclosure in position to expose all air passing therethrough to ultraviolet radiation. The system has 12 high intensity ultraviolet tubes and only one low-efficient fan.
There was therefore a need to develop an apparatus and method for sterilizing air that obviates the problems encountered with the known systems of the prior art.
Summary of the Invention It is an aspect of the invention to provide an improved sterilizing apparatus for both residential and commercial use.
The invention provides a sterilizing apparatus that is simple in construction, economical to manufacture and efficient to use in that it can effectively destroy contaminants in the air.
In accordance with an aspect of the present invention is a portable air sterilization system which comprises an elongated hollow plastic enclosure containing a prefabricated germicidal unit which is cast under pressure from aluminum.
The unit 2 0 has radiation chambers mounted in the longitudinal and transverse directions.
Ultraviolet radiation low-pressure mercury vapor lamps are mounted inside these radiation chambers. A blower means is positioned within the enclosure to draw air downward from the top of the apparatus through the air gap extending around the periphery of the enclosure. As the air enters the enclosure, it passes through the 2 5 radiation chambers and comes out of the bottom partition.
According to an aspect of the present invention is a portable air sterilization apparatus comprising:
a germicidal unit having a plurality of radiation chambers mounted therein;
a source of UV radiation mounted within said chambers for destroying 3 0 bacteria and viruses contained within said air;
blower means for drawing air into said radiation chambers, and outlet means for emitting irradiated air from said radiation chambers and into the environment.
Yet another aspect of the present invention is to provide a method for 3 5 sterilizing indoor air, the method comprising:
drawing indoor air containing bacteria and viruses through a plurality of zigzag passageways;
irradiating said indoor air; and emitting said irradiated air from said radiation chambers and into the environment.
Brief Description of the Detailed Drawings A preferred embodiment of this invention is illustrated in the accompanying drawings, in which like numerals denote like parts throughout, and in which:
Figure 1 is a side cross-sectional view of the apparatus in accordance with an embodiment of the present invention;
Figure 2 is a cross sectional view of the apparatus taken on line A - A of Figure 1;
Figure 3 is a longitudinal cross sectional view taken on lines II - II and III
- III
of Figure 2; and Figure 4 is a longitudinal cross sectional view of the apparatus taken on line IV - IV of Figure 2.
In the drawings, preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood that the description and drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.
Description of the Preferred Embodiment The invention will be readily understood by referring to Figures 1 - 4 in which the portable apparatus of the present invention is shown and referred to as numeral 1.
The portable apparatus 1 is designed to roll about on casters 2. An elongated 2 5 cylindrical plastic enclosure 3 includes top and bottom partitions 4 and 5 and a cap member 6. A plurality of ultraviolet tubes 7 is mounted vertically inside radiation chambers 8-16 and tube ballasts are mounted between top and bottom partitions 4 and 5. Blower means 17 are positioned within enclosure 3 to draw air downward from the top of the apparatus through air gap 18 extending around the periphery of enclosure 3.
3 0 The blower means may be any suitable type of fan which is powered electrically or by gas. One skilled in the art would readily comprehend the types of fans that could be used in the apparatus of the present invention. As the air enters the enclosure 3, it passes through radiation passageways 100 (radiation chambers 8-9-10), 102 (radiation chambers 13-12-11) and 104 (radiation chambers 14-15-16) and comes out of the 3 5 bottom partition S. The passageways 100, 102 and 104 include openings 19 -properly positioned butt plugs 25-36. An example of a path of air in passageway 102 is shown in Figure 1. The air follows the direction of the arrows once is has entered the enclosure 3. The air flows down chamber 13 until it reaches the bottom of the chamber. The butt plug 32 blocks the air from exiting the chamber and the air goes through the opening 21 to chamber 12. Due to the butt plug 31, the air flows upwards until it reaches the top of chamber 12. The butt plug 30 stops the flow of air upwards and the air flows through opening 22. Butt plug 29 causes the air to flow downward until it exits at the bottom of chamber 11. This is repeated in the other two passageways 100 and 104. All three passageways taken together form a prefabricated germicidal unit 37, which is cast under pressure from aluminum. The wall thickness of the radiation chambers is from 1.5 to 2.0 mm and this can vary depending on the size of the apparatus. The inside surface of the radiation chambers is smooth so that ultraviolet light from the lamps is reflected back and forth in the passageways in a criss-cross pattern. Thus, microorganisms and viruses entrained with the air flowing through passageways 100, 102 and 104 are accordingly subjected to maximum contact with the ultraviolet light to such extent that substantially all such microorganisms and viruses are killed.
In order to ensure even air distribution in enclosure 3, the air is discharged from blower 17 to radiation chambers 8, 13 and 14 and comes out of the radiation chambers 10, 11 and 16. Thus, every air passageway includes three radiation chambers.
In low intensity ultraviolet radiation lamps, with the most sensitive 2 0 wavelengths in the neighborhood of 265 NM, the maximum distance between the walls of the ultraviolet tube and the radiation chamber should not exceed 32 mm and the exposure time should not be less than 4 sec. Thus, velocity of the airflow in the passageway is a function of the number of radiation chambers in one passageway and their height (which is equal to the height of the ultraviolet tubes). The number of passageways in the prefabricated germicidal unit 37 effects the processed air capacity of the apparatus only.
Design data for the invention is presented in table 2.
The present invention uses the upper air intake located at about half of the room height, the air stratum at this elevation has the densest population of viable 3 0 airborne particulates.
It is evident from Table 2 that it is possible to achieve the satisfactory output using this invention which has heretofore not been achieved for the portable residential apparatus. Therefore, the method and apparatus of this invention may be readily used as a means of indoor air sterilization in the rooms with a living space of 3 5 about 25-75m in a relatively short period of time.
One skilled in the art understands that the apparatus can be designed to be both portable and stationary. It can also be designed of varying sizes, so long as the operating configurations are maintained such that the apparatus effectively destroys air-borne contaminants.
Although preferred embodiments have been described herein in detail, it is understood by those skilled in the art that variations may be made thereto without departing from the scope of the invention or the spirit of the appended claims.
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Claims (15)
1. A portable air sterilization apparatus comprising:
a germicidal unit having a plurality of radiation chambers mounted therein;
a source of UV radiation mounted within said chambers for destroying bacteria and viruses contained within said air;
blower means for drawing air into said radiation chambers, and outlet means for emitting irradiated air from said radiation chambers and into the environment.
a germicidal unit having a plurality of radiation chambers mounted therein;
a source of UV radiation mounted within said chambers for destroying bacteria and viruses contained within said air;
blower means for drawing air into said radiation chambers, and outlet means for emitting irradiated air from said radiation chambers and into the environment.
2. The apparatus of claim 1, wherein said radiation chambers are arranged in both longitudinal and transverse directions with respect to said unit.
3. The apparatus of claim 1 or 2, wherein the radiation chambers mounted within said apparatus are arranged in the longitudinal direction in groups of three, five, seven and so on, which have interconnections in order provide additional airflow through said radiation chambers.
4. The apparatus of claim 3, wherein said longitudinally arranged radiation chambers are spaced adjacently and have openings provided at each adjoining side.
5. The apparatus of claims 1, 2, 3, or 4, wherein the number of longitudinal radiation chambers may be equal to or different from the number of transverse chambers.
6. The apparatus of claim 1, wherein said source of UV radiation comprises a low-pressure mercury vapor lamp which extends substantially along the entire length of said radiation chamber.
7. The apparatus of claim 6, wherein said vapor lamp emits a light of 265 nm wavelength.
8. The apparatus of claim 1, wherein said blower means comprises a motorized fan unit positioned upstream of said radiation chambers.
9. The apparatus of claim 1, 2, 3, 4 or 5, wherein said radiation chambers are made from aluminum.
10. The apparatus of claim 9, wherein the radiation chambers have a wall thickness of about 1.5-2.0 mm.
11. The apparatus of claim 6, wherein said UV lamp is positioned within 32 mm of a wall of said radiation chamber.
12. A method for sterilizing indoor air, said method comprising:
drawing indoor air containing bacteria and viruses through a plurality of zigzag passageways;
irradiating said indoor air; and emitting said irradiated air from said radiation chambers and into the environment.
drawing indoor air containing bacteria and viruses through a plurality of zigzag passageways;
irradiating said indoor air; and emitting said irradiated air from said radiation chambers and into the environment.
13. The method of claim 12, wherein said zigzag passageway comprise interconnected radiation chambers having a source of UV radiation mounted therein for destroying bacteria and viruses contained within said air.
14. The method of claims 12 or 13, wherein velocity of the indoor air flow is a function of the number of radiation chambers in one passageway and their total height.
15. The method of claims 12 and 13, wherein said radiation chambers increase apparatus output by means of both increased number of passageways and increased number of radiation chambers in the passageway.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2249924 CA2249924A1 (en) | 1998-10-09 | 1998-10-09 | Method and portable apparatus for improving indoor air quality by means of ultraviolet radiation sterilization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2249924 CA2249924A1 (en) | 1998-10-09 | 1998-10-09 | Method and portable apparatus for improving indoor air quality by means of ultraviolet radiation sterilization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2249924A1 true CA2249924A1 (en) | 2000-04-09 |
Family
ID=29425458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2249924 Abandoned CA2249924A1 (en) | 1998-10-09 | 1998-10-09 | Method and portable apparatus for improving indoor air quality by means of ultraviolet radiation sterilization |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2249924A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005002638A2 (en) * | 2003-07-03 | 2005-01-13 | Schroeder Werner | Device for purifying used air containing harmful substances |
| EP1977771A1 (en) * | 2007-03-27 | 2008-10-08 | John J. Hayman | Photocatalytic air treatment system and method |
-
1998
- 1998-10-09 CA CA 2249924 patent/CA2249924A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005002638A2 (en) * | 2003-07-03 | 2005-01-13 | Schroeder Werner | Device for purifying used air containing harmful substances |
| WO2005002638A3 (en) * | 2003-07-03 | 2005-03-03 | Werner Schroeder | Device for purifying used air containing harmful substances |
| EP1977771A1 (en) * | 2007-03-27 | 2008-10-08 | John J. Hayman | Photocatalytic air treatment system and method |
| EP2361639A3 (en) * | 2007-03-27 | 2012-01-18 | John J. Hayman Jr. | Photocatalytic air treatment system and method |
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