Patent Application
20090202397
Volatile organic compounds are petroleum-based chemicals which are often found at elevated levels in many houses. Thousands of possible volatile organic compounds outgas from common household products such as, for example, synthetic fragrances (as found in soaps, candles, air fresheners, incense and potpourri), paint, carpet, furnishings, glues, plastics, pressed wood products (such as plywood and particle board), and even fresh flowers. Formaldehyde is one example of a volatile organic compound (VOC) that can be a particular problem in homes because it is found in many building materials such as caulks and adhesives, paint, furniture, etc. Formaldehyde is a desensitizing substance that lowers the ability to recognize or sense other potentially harmful chemicals. Prolonged exposure to formaldehyde often causes headaches, numbness or tingling of extremities, lightheadedness, inability to concentrate, anxiety, and depression. Outgassing can be diluted by improving air flow; however, where a source of formaldehyde or other volatile organic compound is organic matter such as mold, outgassing can be continuous and persistent. Volatile organic compounds that are outgassed as waste products of mold can be more dangerous to an individual's health than mold spores drifting through the air.
In addition to producing the unpleasant side effects discussed above, a VOC can produce noticeable and noxious odors. For example, the treatment processes for many municipal water sources utilize chlorine dioxide as a disinfectant. When a faucet is turned on and the water is running, the chlorine dioxide suspended within the water can diffuse into the air. The airborne chlorine dioxide, in turn, can combine with outgassed volatile organic compounds found in the ambient air to produce a noxious odor. These compounds often collect in enclosed areas such as, for example, laundry rooms, basements, bathrooms and closets that have little ventilation. The lack of ventilation often results in a concentration of these odor causing compounds. Furthermore, the potential for producing these noxious odors directly correlates with the level of a VOC within the home and the amount of chlorine dioxide diffused from the water. Thus, any reduction in the VOC level will result in a corresponding risk reduction for producing these noxious odors.
In an effort to increase air flow, dilute and possibly reduce exposure to volatile organic compounds many devices incorporating fans, impellers and electro-kinetic techniques have been developed. For example, as shown in
In an effort to remove, or at least reduce, the level of volatile organic compounds in airflow path A-A and ambient air, some air delivery systems replace the filter 110 with a high-efficiency particulate arrester (HEPA) filter and a carbon filter. The HEPA filter can collect significant amounts of large particulate matter (0.3 μm and above) and the carbon filter can absorb the volatile organic compounds and the associated unpleasant odors directly from the ambient air and the airflow path A-A. However, HEPA filters have limited effectiveness when attempting to collect particulate matter or airborne particles 114 smaller than 0.3 μm. Moreover, both HEPA and carbon filters eventually saturate and require replacement to prevent excess volatile organic compounds and odors from being dumped back into the ambient air and the airflow path A-A.
The differences in electrical potential between the emitter array 122 and the collector array 124 encourages the ionized air to move along the airflow path A-A. Charged contaminants and airborne particulates 114 suspended within the ionized air are electrostatically attracted to the surface of the collector array 124. The electrostatic attraction between the particulates 114 and the collector array 124 remove the charged particulates 114 from the airflow path A-A. The high voltage charge provided by the power source 126 generates and releases ionized air which has been found to be beneficial in small quantities in eliminating many of the VOC and noxious odors. However, it has been theorized that excessive amounts of ionized air can be undesirable. Thus, it is often necessary to reduce the intensity and frequency of the high voltage pulses to decrease ionized air production. This reduction often results in a decrease in the overall airflow and efficiency of the electro-kinetic air delivery system 120.
Another common pollutant is ozone. The bulk of ground level ozone is an invisible gas that forms when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, household paints, stains and solvents and other sources react chemically in the presence of heat and sunlight. The presence of ground level ozone presents serious air quality problems in many parts of the United States, particularly in large cities. For humans and other animals, ozone can be harmful when it is inhaled in sufficient quantities to cause a number of respiratory effects. Ozone can trigger attacks and symptoms in individuals with pre-existing health conditions, such as asthma or other respiratory infections.
Weather plays a key role in ozone formation. The highest ozone levels are usually recorded in summer months when temperatures approach the high 80s and 90s and when the wind is stagnant or light.
It is recommended that when ozone levels are high, people at risk should take simple precautions:
However, these precautions are directed at avoiding areas where the levels of ozone are high. They do not alleviate the problem of ozone itself.
Accordingly, it may be desirable to provide an efficient and versatile air delivery system that can reduce volatile organic compounds and ozone emissions.
Illustrative examples of air delivery and conditioning systems configured to reduce ozone and volatile reactive compounds in the ambient air and along an airflow path are disclosed. In one example, an air delivery and conditioning system includes a housing having a substantially hollow interior that defines an air inlet fluidly connected to an air outlet. The housing carries at least one airflow generator positioned substantially adjacent to the air inlet and configured to create an airflow between the air inlet and the air outlet. The housing further supports a conditioning matrix positioned next to the air outlet along the airflow created by the at least one air flow generator, The conditioning matrix is coated with a reactive material that interact with the airflow between the air inlet and the air outlet to reduce ozone.
In an embodiment compositions for removing ozone from air are also disclosed. The ozone reduction compositions include a porous support structure which allows for the passage of air and has an ozone reactive surface. The support can be housed such that it can be attached to fans or other air moving devices such that as air moves, it passes by the reactive surface of the support where at least a portion of the ozone is removed.
Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the figures.
Returning to
The housing 202 further includes a control cap 208 having an access panel 210, and controls 212, 214, 216. The access panel 210 can be a flip-up panel or a removable panel that allows access to the air flow generators supported within the housing 202. Specifically, a user may remove the access panel 210 to perform maintenance or service on, for example, the arrays 122, 124, the fan(s) 108 and one or more of the filter screens, conditioning surfaces and conditioning matrices discussed below. The controls 212, 214, 216 can be, for example, a speed control, a selector, and a power switch, respectively. The speed control 212 can control the operation of the fan(s) 108 or the arrays 122, 124 which, in turn, varies the volume and speed of air along the airflow path A-A. The selector 214 can be an option selector that controls the use of the fan-based system, the electro-kinetic air delivery system 120, and a conditioning system generally indicated by the reference numeral 220. The power switch 216 can engage the power source 126 or other potential source necessary to operate the fan-based air delivery system 100 and the electro-kinetic air delivery system 120.
The housing 202 supports the conditioning system 220 which includes a filter screen or grill 222, a conditioning matrix 224 and an activator lamp 226. In one embodiment, the filter screen 222 is a pre-screen filter that removes large particulates 114 from the ambient air before the air enters the housing via the air inlet 104. The filter screen 222 can be, for example, a passive fine wire mesh or an active metallic mesh coated with a reactive material such as titanium dioxide (TiO2) that reacts with the volatile compounds in the ambient air. Similarly, the conditioning matrix 224 could be a passive or active mesh or a “honeycomb” filter arranged to remove unwanted particles and compounds from the ambient air. Often, the conditioning matrix 224 will be an active metallic mesh coated with a catalytic compound selected to react with any unwanted ozone or volatile organic compounds present in the ambient air. Depending on the type, coating and function of the conditioning matrix 224 and the filter screen 222, the activator lamp 226 may be employed to initiate the reaction between the catalytic coating and the unwanted ozone or VOC.
It will be understood that by varying the dimensions of the support members 232, 234, 236, and 238, the corresponding rectangular interior of the frame 240 can be varied to support any desired number or configuration of the fan units 246. For example, the overall housing size can be reduced by removing two of the four fan assemblies 246 and decreasing the length of the support members 232 and 236 by half.
It will be understood that while the air delivery and conditioning system 200 shown in
As previously mentioned, the air delivery and conditioning system 200 supports the conditioning system 220 having one or more conditioning elements or matrices. The conditioning system 220 in this exemplary embodiment includes a fine wire mesh filter screen 254 stretched across a rigid or semi-rigid frame 256. The mesh of the filter screen 254 can be sized to remove dust large particular matter 114 that would otherwise gather and potentially clog the fan units 246.
The conditioning system 220 can further include a conditioning matrix 224. In one embodiment, the conditioning matrix 224 includes an active manganese oxide coating capable of reacting with and removing selected compounds and chemicals from the ambient air. In one embodiment, the conditioning matrix 224 is positioned adjacent to the air outlet 106. This arrangement of the conditioning matrix 224 allows for the reduction or removal of compounds or chemicals suspended within the ambient air traveling along the path airflow A-A as the air exits the housing 230 through the air outlet 106. While the housing 230 illustrated in
To mount or secure the housing 260, the movable window portion 272 can be arranged in a full open position to allow the housing 260 to be rested within the sash 258. Upon proper alignment and positioning of the housing 260 within the sash 258, the movable window portion 272 can be shifted into an abutting relationship with a top surface 274 of the frame 270. Depending on the size and shape of the window and sash 258, it may be advantageous to use one or more spacer or filler members (not shown) between the frame 270 and the sash 270 to seal and support the housing 260 in a desired location.
In one embodiment, the housing 260 supports the fine wire mesh filter screen 254 and the conditioning matrix 224. As previously discussed the filter screen 254 can remove large particular matter from the ambient air and the airflow path A-A, and prevent insects or other pests from entering through the air inlet 104 of the system 200. The housing 270 can further support the conditioning matrix 224 to remove or reduce the presence of ozone or volatile organic compounds within the ambient air.
The conditioning system 220 and the associated filter screens 222, 254 and conditioning matrixes 224 can be affixed and incorporated into the air delivery and conditioning system 200 in various well-understood manners. Inclusion of filter screens 222, 254 and conditioning matrixes 224 allow for removal and reduction the volatile organic compounds (VOC) and/or the excess ozone (O3) contained within the ambient air and transported along the airflow path A-A.
One technique for conditioning and removing pollutants or contaminants from an air flow is photocatalysis. Generally, photocatalysis utilizes a reactive material or catalyst and an ultraviolet (UV) radiation source or UV lamp 226 arranged to activate the catalyst. The activated catalyst, in turn, breaks down or oxidizes the hazardous chemicals such as VOC and O3. For example, one such catalyst is microporous titania ceramic (titanium dioxide, TiO2), a thin layer of which can be coated on a surface of the filter screen 222, 254, and the matrix 224. Titanium dioxide is a semi-conducting photocatalyst having a band gap energy of 3.2 eV. When titanium dioxide is irradiated with photons having wavelengths of less than 385 nanometers (nm), the band gap energy is exceeded and an electron is promoted from the valence band to the conduction band. The resultant electron-hole pair has a lifetime that enables its participation in chemical reactions. The UV lamp 226 (or a source of radiation outside of the UV spectrum having a wavelength less than 385 nm) can be used to activate the titania ceramic, which when illuminated can oxidize volatile organic compounds present in the ambient air and the airflow path A-A, breaking the compounds into water and carbon dioxide. In addition, irradiating the ambient air traveling within the airflow path A-A with ultraviolet light from the UV lamp 226 can substantially eliminate microorganisms within the airflow.
In one embodiment of the electro-kinetic air delivery system 120 described herein, an interstitial or driver electrode (not shown) can include a photocatalytic coating, or can be embedded or impregnated with photocatalytic material. Use of a photocatalytic coating can promote oxidation of air in close proximity to the interstitial or driver electrode array. In other embodiments, the walls of the housings 202, 230 and 260 can be embedded or impregnated with photocatalytic material, or the walls of the housing can include a photocatalytic coating. In the embodiments shown in
It will be understood that the porous or “honeycomb” structures need not have a regular grid-like structure. For example, the porous structure can have a web-like structure, or a spiral structure. Further, in some other embodiments, where an airflow already exists (for example in a furnace duct), the porous structure can be placed within the airflow (for example disposed within the furnace duct) rather than within an airflow generated by an electro-kinetic air delivery system 120 or fan-based air delivery system 100.
The UV lamp 226 will generally be positioned such that the porous surface of the conditioning matrix 224 is substantially irradiated by UV light. The UV lamp 226 could be, for example, a Phillips model TUV 15W/Gi5 T8, a 15 W tubular lamp measuring about 25 mm in diameter by about 43 cm in length. Another suitable UV lamp 226 is the Phillips TUV 8WG8 T6, an 8 W lamp measuring about 15 mm in diameter by about 29 cm in length. It will be understood that other UV light sources that emit the desired wavelength can utilized because there are a myriad of different ways of introducing and activating the photocatalytic material arranged in the airflow.
Various types of catalysts can be used in a photocatalytic coating. For example, as described above the photocatalytic coating can be comprised of titania ceramic and of an alternative metal oxide, such as zinc oxide, cuprous oxide, silicon dioxide, etc. Oxides of manganese, copper, cobalt, chromium, iron and nickel are known to be active in oxidation reactions. Further, mixed oxides can be used for photocatalysis. For example, in some circumstances copper chromite (CuCrO4) can be at least as active in promoting oxidation as cuprous oxide (CuO). These are just examples of coatings that can be used with embodiments of the present invention. Still further, noble metals can be effectively used to oxidize VOCs. For example, oxidation reactions on platinum and palladium are known to occur very rapidly.
In some embodiments, a noble metal can be impregnated or applied to a surface as a coating, for example with another substance (the amount of platinum and palladium is dependent on the level of VOCs present, but effectively a fraction of a percent relative to a total surface area on which it is applied). Oxidation of a VOC using a base metal photocatalytic coating may produce carbon monoxide (CO) as an oxidation byproduct. In one embodiment of the present invention, a noble metal, such as platinum or palladium, can be deposited, impregnated or otherwise applied to the base metal photocatalytic coating, or a surface or porous structure including the base metal photocatalyst.
The conditioning system 220 and the associated filter screens 222, 254 and conditioning matrixes 224 can be configured to remove and condition volatile organic compounds from the ambient air and the airflow path A-A. Alternatively, the conditioning system 220, or components of the conditioning system, can configured to remove or reduce excess ozone (O3) contained within the ambient air and the airflow path A-A.
The conditioning matrix 224 and the filter screens 222, 254 can be configures as an ozone-reducing structure (ORS) to supplement or replace the photocatalytic or fine mesh screen matrices and filters discussed above. The ozone-reducing structure can be positioned at any location in the device that will provide for a reduction in the level of ozone that passes out of the air conditioning system. In one embodiment, the conditioning matrix 224 or ozone-reducing structure is positioned between the emitter array 122 and the collector array 124. Alternatively, the ozone reducing structure may be arranged adjacent to the air outlet 104 to condition the airflow A-A prior to leaving the housing 202, 230, and 260. Further, the conditioning system can be positioned in a separate housing positioned on the exterior of the device through which outlet air can pass.
It will be understood that the ozone reducing structure can in and around various elements of the electro-kinetic air delivery system 120 to reduce and control excess production of ozone. Alternatively, the ozone reducing structure can be integrated into the conditioning matrix 224 as shown in
One alternate embodiment of the ozone reducing structures includes a grounding member that electrically connects the ORS or conditioning matrix 224 to the electrical ground of the system 200. In this way, the ORS or conditioning matrix 224 will not emit or contribute to the ionizing electric field generated by the electro-kinetic air delivery system 120. The grounded ORS or conditioning matrix 224 can create a voltage potential difference between the emitter electrodes 122 which causes the ambient air, the airflow A-A, and the ionized particles 114 suspended within in the air to flow toward the conditioning matrix 224. The conditioning matrix 224 thereby can collect the ionized particles suspended in the air that are not collected by the collector array 124 and also reduce or control excess ozone. However, it is possible that the ORS or conditioning matrix 224 could be coupled to the positive or negative terminals of the power source 126. If the ORS or conditioning matrix 224 is to be charged, it may be desirable provide a charge that is opposite of whatever charge is applied to the emitter electrodes 122 in order to promote air flow between the two elements.
The ORS or conditioning matrix 224 can be coated with a catalyst material selected to reduce or neutralize ozone in the ambient air and along the airflow path A-A. In one embodiment, the entire surface of the conditioning matrix 224 is coated with the catalyst, such that each opening or honeycomb cell 276 has catalyst material along its inner surfaces. Thus, as ozone passes through each cell 276, the catalyst substance converts the ozone into the oxygen and reduces the amount of ozone exiting conditioning matrix 224. A number of commercially available ozone reducing catalysts can be used, such as “PremAir” manufactured by Englehard Corporation of Iselin, N.J. Some ozone reducing catalysts, such as manganese chloride, manganese dioxide, are not electrically conductive, while others, such as activated carbon, are electrically conductive. Other examples of electrically conductive ozone reducing catalyst include, but are not limited to, noble metals.
The present disclosure generally relates to devices for removing ozone from air. In an embodiment, the device generally can include a support having an ozone reactive surface. The support can be mounted to a housing. The housing can be adapted to be placed in an air flow such that at least a portion of the air flow can flow through the support. As the air flows through the support, at least a portion of the air flows within reactive distance of the surface of the support such that the air contacts the reactive surface and a portion of the ozone from the air is removed. The housing can be mounted to any air flow device however, it is particularly useful for mounting to devices whose primary purpose is the movement of air, including electro-mechanical and electro-kinetic air movement devices.
Many suitable supports for the ozone reactive surface are known and can be used. Suitable supports include plastic and metal supports to which an ozone-reactive material can be incorporated or attached. The supports can be sufficiently porous to allow air flow without undue restriction. For example, the structure can be a honeycomb structure through which air can flow. The size of the holes or cells in the honeycomb of the support will depend upon the air flow device that is used with the device. For example, where air flow is generated by fans, the inside diameter of the holes can be smaller so long as the fans are powerful enough to maintain air flow through the support. However, when air flow is slower, such as when it is generated by certain electro-kinetic devices, the size of the openings in the structure will generally be larger to ensure that sufficient air flow can occur when the support is employed. It is well within the level of skill of one having skill in the art to select a porous structure having openings of a sufficient diameter to allow air flow in the resulting application.
The surfaces 362 of the grid 354 are preferably made of a series of metal sheets which are attached to form the overall honeycomb shape, as illustrated in
The grid 354 preferably has dimensions to allow the device 100 to maintain airflow velocity through the device. The surfaces 362 of the grid 354 have a width dimension which is designated as the distance from the inlet side 356 to the outlet side 358 of the grid 354. Additionally, each air passageway has a pitch dimension which is the distance between opposing parallel sides of the conductive surfaces 362. The width dimension and the pitch dimension of the grid 354 can be selected such that the highest airflow rate can be achieved. In particular, the pitch dimension is such to facilitate a sufficient airflow rate through the grid 354 with minimum airflow restriction. Additionally, the optimal pitch and width dimensions of each cell 360 provide a large surface area, when applied with a catalyst material, will significantly reduce the amount of ozone exiting the air flow device. In an embodiment, the pitch dimension of each air passageway 360 is approximately 0.125 to 0.25 inches, although other dimensions can be used.
The surfaces 362 are preferably coated with a catalyst material, whereby the catalyst material acts to reduce or neutralize ozone in the airflow without being chemically converted itself. Several methods for coating such surfaces are known in the art and can be used. The surfaces 362 of the support can be coated with an ozone-reducing agent or catalyst which can be a compound such as an oxide, for example a metal oxide, including silicon dioxide or manganese dioxide, for example. Some ozone reducing catalysts, such as manganese chloride, manganese dioxide, are not electrically conductive, while others, such as activated carbon, are electrically conductive. Other examples of electrically conductive ozone reducing catalyst include, but are not limited to, noble metals. As stated above, the optimal pitch and width dimensions of each cell 360 in the ORS 350 provide a large surface area upon which the catalyst material can be disposed. Preferably, the entire grid 354 is coated with the catalyst, whereby each cell 360 has catalyst material along its inner surfaces. As ozone passes through each cell 360 in the ORS 350, the catalyst substance on the conductive surfaces 362 converts the ozone into the oxygen, thereby reducing the amount of ozone exiting the ORS 350. The catalyst coated cells 360 in the grid 354 of the ORS 350 will thereby significantly reduce the amount of ozone exiting an air flow device. Several commercially available ozone reducing catalysts are known and can be used, including for example, “PremAir” manufactured by Englehard Corporation of Iselin, N.J.
A number of methods for attaching the ozone reducing support structure to the housing are known and can be used. For example, the device shown in
In an embodiment, the housing to which the ozone reducing support is attached can be a protective covering for the air movement device. Alternatively, the housing to which the ozone reducing support is attached can be adapted to attach to a protective covering for an air movement device.
The present invention is particularly well suited for use with devices that move ambient air, as they are specifically designed for removing ozone from ambient air in order to purify air, including air in cars, homes, offices, airplanes and the like. As such, they can be used with electromechanical devices such as fans. For example, the ozone reducing devices can be mounted into a housing and placed in central air vents of homes, office buildings, automobiles, airplanes, or on window fans. The present disclosure contemplates that ozone reduction devices can be adapted for use with any fan.
The present disclosure also contemplates the use of ozone reduction devices with electro-kinetic air conditioner devices. In such devices, the ozone reduction supports can be mounted directly in protective grill coverings of such devices or they can be mounted in housings that are adapted to be mounted on such grill coverings.
In an embodiment, an air flow device is contemplated that contains a support having an ozone reactive surface mounted to a housing having an attachment means for positioning the housing in an air flow generated from the device such that a portion of the generated air flow can flow into the support and contact the reactive surface so as to remove a portion of the ozone from the air. The device further includes a device for generating an air flow that can be either an electro-kinetic air flow device or an electromechanical air flow device. For example, the electromechanical device for generating air flow can be a fan while an electro-kinetic air-flow device can be an Ionic Breeze®, such as is sold by Shaper Image Corp., San Francisco Calif.
Any housing that can hold the ozone reducing support securely and that does not restrict air flow is suitable for use in the present invention. The housing can be a protective cover for an air flow device or can be attachable to such a cover. The housing can be made of a hard plastic or metal or other material so long as the ozone reducing support can be held securely.
In housings that are adapted to be mounted to other protective coverings, any type of attachment method can be used, so long as the device can be securely mounted to the protective covering. For example, as illustrated in
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US06/28656 | 7/24/2006 | WO | 00 | 11/17/2008 |
| Number | Date | Country | |
|---|---|---|---|
| 60701686 | Jul 2005 | US | |
| 60701772 | Jul 2005 | US |
