CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 1 19 to U.S. Provisional Patent Application Serial No. 61/417,090, filed on November 24, 2010, entitled, "Air Purification System", the entire disclosures of which is incorporated by reference herein.

BACKGROUND

[0002] The air used to air condition structures (i.e., houses, buildings) can originate from either the inside of a structure or outside of a structure. Some problems associated with using air from outside a structure to air condition the indoor areas of a structure include the introduction of outdoor contaminants and particulates commonly found in outdoor air.

Outdoor air may contain smoke and smog, which can contain carbon monoxide, ozone, and other pollutants that may irritate a person's respiratory system. In addition, introduction of mold spores and pollen, which are common particulates found in outdoor air, may cause unwanted mold to grow inside and induce allergic reactions to persons occupying the structure. In addition to the air contaminant that may be brought into a building from the outside, air contaminants may leak from a basement (i.e., through a crawl space) and accumulate in areas commonly occupied by people. Air escaping a basement may carry mold spores and potentially harmful gases, such as radon, which can pose health risks for those occupying the structure.

[0003] In addition, most structures generally "breathe" due, at least in part, to changes in outside air pressure relative to air pressures within structures. For example, when air pressure outside of a structure is greater than the air pressure within a structure, the outside air tends to leak into the structure. When air pressure outside a structure is less than the air pressure within a structure, the air inside the structure tends to leak out of the structure. Generally, the pressure differential between the outside of a structure and the inside of a structure may be caused by any number of factors (i.e., atmospheric changes,

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wind, exhaust fans running, stoves and fireplaces in operation, etc.). The continual

"breathing" of a structure may be essential for supplying fresh oxygen to occupants of a structure. However, if air leakage into a structure is uncontrolled, the air brought into a structure may bring in undesirable contaminants and particulates that eventually may be inhaled by occupants.

[0004] Some conventional air purification systems that are currently available recirculate the air within the structure, which prevents total indoor air purity to be achieved for at least the reasons described above. In addition, some air purification systems expel harmful byproducts, such as ozone, into the air of structures as a result of their air purification processes. Ozone is a harmful air pollutant that can be harmful to breathe, and long-term exposure to ozone may permanently reduce a person's breathing ability. In particular, children, the elderly, and people with respiratory diseases can be especially sensitive to ozone inhalation. Therefore, for at least the reasons described above, there is a need for an air purification system that can supply purified air to the inside of a structure without expelling unhealthy levels of ozone into the structure.

[0005] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

SUMMARY

[0006] Some implementations of the air purification system include at least one housing. The housing can incorporate a mounting mechanism for mounting the air purification system to a structure. In addition, the housing may further include an air inlet and an air outlet. Furthermore, the air purification system can include a fan that may be actuated by a control circuit. Additionally, the control circuit can control a rate of airflow through the air purification system by controlling the fan speed. The housing may further include at least one filter positioned within the housing and an ultraviolet light source mounted within the housing. Additionally, at least one photo-catalytic element may be positioned adjacent the ultraviolet light source such that air passed through the air purification system is exposed to the photo-catalytic element and the ultraviolet light source. The housing may further include at least one chemical catalyst element that is exposed to air that passes through the air purification system.

[0007] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other aspects will now be described in detail with reference to the following drawings.

[0009] FIG. 1 illustrates an embodiment of an air purification system.

[0010] FIG. 2 illustrates a flow chart of a pressure differential function of the air purification system.

[0011] FIG. 3 illustrates a flow chart of a heating function of the air purification system.

[0012] FIG. 4 illustrates a flow chart of a cooling function of the air purification system.

[0013] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0014] This document describes an air purification system that is at least able to draw in air from the outside of a structure and purify the air to at least a level that is generally healthy for human inhalation. In addition, the air purification system may function to provide warmer or cooler purified air to the inside of a structure. Furthermore, the air purification system may include a feature to purify circulated air to the inside of a structure. In alternative implementations, an air purification system may also include a solar heating element that can function to increase the temperature of the air purified in the air purification system.

[0015] Described herein is an air purification system that includes features that allow it to be integrated into a structure and provide an airflow pathway between the outside (i.e. "outside space") and inside (i.e. "inside space") of the structure. The air purification system may be coupled to an air duct or pipe that is already part of the structure so that installation of the air purification system generally does not require additional holes or penetrations into any walls of the structure. Alternatively, generally any wall of a structure may be penetrated in order to adapt an air purification system to the structure. In general, the air purification system may be integrated into a structure so that it can purify air as it is forced from the outside of the structure into the inside area of the structure, as will be discussed in more detail below.

[0016] Turning now to the figures, FIG. 1 shows an implementation of the air purification system 100. The air purification system 100 can include a housing 102 that generally houses the components of the air purification system 100. The housing 102 may be formed of one or more parts and may include features (i.e., mounting holes, fasteners, etc.) that can assist in securing the placement of the air purification system 100 to a structure. In addition, the housing 102 of the air purification system 100 can accommodate a fan 104 that, when circulating, forces air to be passed through the air purification system 100. For instance, a fan 104 in the housing 102 is arranged to draw in air from the outside of a structure, force it through the air purification system 100, and expel the newly purified air into the structure. The fan 104 can be a variable speed fan such that the rate at which air is passed through the air purification system 100 can be varied. The speed of rotation of the fan 104 may be manually controlled by a user or programmed, as will be discussed in further detail below. Although described herein as a fan, any number of mechanisms may be used to force air through the air purification system 100 without departing from the scope of the present disclosure.

[0017] In general, if all structural fixtures allowing air into the building (i.e., windows, doors, etc.) are generally closed and the air purification system 100 is providing adequate airflow into the structure from the outside, the air purification system 100 may essentially become the sole source of outside air into the structure. Therefore, not only can the air purification system 100 generally provide the sole source of outside air into a structure, but it can also create and maintain a pressure differential between the inside and outside of the structure. For instance, as the air purification system 100 forces air from the outside of a structure and expels it into the inside of a structure, the air purification system 100 ultimately can cause the inside of the structure to have a higher pressure than the outside of the structure. The ability of the air purification system 100 to create and maintain this pressure differential generally limits any air entering the structure from the outside to only through the air purification system 100. Therefore, the remaining air leaks throughout the structure, which may have otherwise been a source of contaminants entering the building, are generally limited to air exiting the building. By limiting the source of airflow into the structure to generally solely being through the air purification system 100, the reduction in outside contaminants (i.e., mold spores, pollen, dust, smoke, etc.) entering the inside of the structure can be reduced due to the air purification system's 100 ability to eradicate air contaminants as the air is passed through the air purification system 100, as will be described in more detail below. Ultimately, this may help reduce allergic reactions, breathing irritations and other health problems associated with exposure to air contaminants for those people occupying the structure.

[0018] The air purification system 100 may be sized, dimensioned and powered such that it can appropriately maintain clean air within an area of a structure. For example, the air purification system 100 may handle 0.5 air changes per hour, which is generally known to be the air exchange rate (AER) necessary to continuously ventilate a house under moist conditions. However, the air purification system 100 may be sized and powered to effectively maintain cleaner air in a number of sized and dimensioned structures without departing from the scope of the present disclosure.

[0019] The air purification system 100 includes air purification technology that reduces, if not eliminates, the release of ozone into the inside area of the structure to which it is providing purified air. Ozone can cause health problems, including respiratory tract irritation and breathing difficulties. Therefore, the air purification system is configured to 4

significantly reduce, if not prevent, the release of ozone into the inside of the structure due to any air purification processes, as will be discussed below.

[0020] As illustrated in FIG. 1 , the air purification system 100 includes one or more of a filter 106, photo-catalytic element 108, ultraviolet (UV) light source 1 10, reflective material 1 12, and chemical catalytic element 1 14. In addition, and also shown in FIG. 1 , the air purification system 100 may further include a louvered screen 1 16 and a directional outlet 1 18. The air purification system 100 may be installed into a structure such that the louvered screen 1 16 is in generally in contact with the outside air of the structure and the directional outlet 1 18 is generally in contact with the inside air of the structure. In this configuration, the fan 104 can function to draw air in from the outside and force it to pass through the louvered screen 1 16, filter 106, photo-catalytic element 108 and become exposed to UV light. After the air is exposed to the UV light source 1 10, the fan 104 can continue to force the air out through the chemical catalytic element 1 14 and directional outlet 1 16 before being expelled into the inside of a structure.

[0021] In general, the louvered screen 1 16 provides a directional airflow inlet into the air purification system 100. Additionally, the louvered feature of the louvered screen 1 16 assists in reducing turbulent flow and minimizing, if not preventing, direct UV light emissions from the air purification system 100. Once air has passed through the louvered screen 1 16, the air is then forced through one or more filters 106, as shown in FIG. 1.

Generally, the one or more filters 106 function to capture and eliminate various sized particulates from the air. In general, filters may function to capture generally larger-sized particulates. However, any number of filters may be used that are designed to capture any number of types and sizes of particulates without departing from the scope of the present disclosure.

[0022] Once the air has passed through the one or more filters 106, the air is then forced through the photo-catalytic element 108 and exposed to the UV light source 1 10. For example, the photo-catalytic element 108 may be comprised of a thin-film photo-catalyst, such as Titanium dioxide, that is generally coated over an element that allows air to pass through (i.e., a louvered screen). Similar to the louvered screen 1 16 described above, louvers may be used again here to minimize direct UV light emissions from the air purification 2011/061964

system 100 and reduce turbulent airflow. The photo-catalyst coating enables particulates, such as organic compounds, in the air to come into contact with the photo-catalyst in order for them to be destroyed upon exposure to UV light. After the particulates have come into contact with the photo-catalyst, the particulates are exposed to the UV light source 1 10. As described above, the U V light source 1 10 activates the photo-catalyst to destroy the remaining particulates in the air. Reflective material 1 12 may surround at least a portion of the UV light source 1 10, and may function to increase the intensity of the UV light and exposure of the UV light to the particulates. Increased intensity and exposure of UV light to the particulates can increase the effectiveness in activating the photo-catalyst and eradicating the particulates from the air. In general, the combination of a photo catalyst and UV light can effectively eradicate any remaining particulates in the air the filter was unable to remove. Any number of photo-catalysts may be used to eliminate particulates from the air without departing from the scope of the present disclosure.

[0023] After the air has been exposed to the UV light source, the air is forced past the fan 104 and through a chemical catalytic element 1 14 before being expelled through the directional outlet 1 18 and into the inside of the structure. The chemical catalytic element 1 14 may be a screen or filter that is generally coated with a chemical catalyst. The chemical catalyst generally functions to decompose ozone that was formed as a byproduct during the air purification process conducted in the air purification system 100. As mentioned above, ozone may be hazardous to a person's health, so it is a benefit of the air purification system 100 to generally prevent the expulsion of ozone. By way of example, chemical catalysts such as those including manganese dioxide may be used to decompose ozone in the air purification system 100. However, any number of chemical catalysts may be used to cause the decomposition of ozone without departing from the scope of the present disclosure.

[0024] In addition, the directional output 1 18 may include slats that enable a user to direct the outflow of air from the air purification system 100 into the inside of the structure. Additionally, and shown in FIG. 1 , the airflow passage way leading up to the directional output 1 18 may be designed and structured such that it is a generally cylindrical passageway. A generally cylindrical airflow passageway can promote laminar flow, which can ultimately provide a desirable streamline flow from the air purification system 100 into the inside of a structure. However, any number of shaped airflow passageways may be provided in the air purification system 100 that promote a laminar flow of air through the air purification system 100 without departing from the scope of the disclosure.

[0025] The air purification system 100 may further include a control circuit that may be contained within at least a part of the housing 102. For example, the control circuit may be located on the portion of the housing that is exposed to the inside of the structure.

Furthermore, the control circuit can assist in providing the air purification system 100 with user-programmable features and functions conveniently accessible to a user from the inside of the structure. The control circuit may control any number of electrically powered components and features within the air purification system 100. For example, the control circuit can control the fan 104 speed in order to produce a desired rate of airflow through the air purification system 100. Additionally, the control circuit can enable the fan speed to be manually controlled by a user, or programmed to run at a certain speed or range of speeds. In addition, the control circuit can include additional features that take measurements (i.e., pressure, temperature, etc.) and vary the speed of the fan 104 generally automatically according to the measurements taken, as will be discussed in further detail below.

[0026] By way of example, the control circuit may include pressure measuring elements that can take pressure readings both inside and outside of the structure. From these measurements, the control circuit can then either increase or decrease the fan speed, as necessary, in order to achieve a pressure differential value or range between the inside and outside of the structure. The pressure differential value or range may be set by a user, or it may be a pre-programmed setting embedded within the air purification system 100. The ability of the air purification system 100 to monitor this pressure differential enables the air purification system 100 to efficiently respond to changes in pressure within the structure, such as when a door is opened, without relying on a user.

[0027] FIG. 2 is a flow chart of a method 120 for controlling an air purifier in accordance with some implementations. The method 120 can be used to determine the pressure differential existing between the outside and inside of a structure and vary the fan speed accordingly. As shown in FIG. 2, inside pressure is measured at 122, and outside pressure is measured at 124. The inside and outside pressures can be measured by one or more pressure measuring elements, such as a digital barometer or manometer. However, any number of pressure measuring elements may be employed by a pressure monitoring circuit of the air purification system 100 in order to measure at least the inside and outside air pressure of a structure. For example, a pressure measuring element employed to measure the inside air pressure of a structure may also be the same pressure measuring element that measures the outside air pressure of the structure. At 126, the method 120 further includes determining whether the measured inside air pressure is sufficiently greater than the measured outside air pressure. If the measured inside pressure is sufficiently greater than the measured outside pressure, the fan speed is generally not changed. However, if the inside air pressure is not sufficiently greater than the outside air pressure, the fan speed is changed. At 128, it is determined whether the inside air pressure is too high. At 130, the fan speed is decreased if the inside air pressure is determined to be too high. At 132, the fan speed is increased if the inside air pressure is determined to be too low. As described above, an increase in fan speed increases the air expelled into the structure by the air purification system 100, which can eventually cause the pressure within the structure to increase relative to the outside of the structure.

[0028] In addition to purifying air, the air purification system 100 may provide warmer or cooler air to the structure relative to the air temperature inside the structure. For example, the control circuit can include temperature measuring elements (i.e., thermistors, thermocouples, etc.) that can measure the outside and inside air temperatures of a structure. From these measurements, the control circuit can then either increase or decrease the fan speed, as necessary, in order to achieve a defined temperature value, or range, inside the structure. The defined temperature value, or range, may be manually set by a user, or it may be a pre-programmed setting of the air purification system 100. The ability of the air purification system 100 to monitor the inside temperature of the structure enables the air purification system 100 to efficiently respond to changes in temperature within the structure, such as when a door is opened, without relying on a user.

[0029] FIG. 3 is a flowchart of a method 140 for controlling temperature within a structure using an air purification system, in accordance with implementations described herein. The method 140 can be used to determine the temperature inside a structure and vary T/US2011/061964

the fan speed accordingly in order to generally maintain warm inside air temperatures. As shown in FIG. 3, inside temperature is measured at 142. At 144, it is determined whether the inside temperature is at a desired temperature, or within a desired temperature range, which may be user defined or pre-programmed. If the measured inside temperature is at the desired temperature, or within the desired temperature range, the fan speed is generally not changed. However, if the inside air temperature is not at the desired temperature, or within the desired temperature range, the fan speed is changed. At 146, it is determined whether the inside air temperature is too high. At 148, the fan speed is decreased if the inside air temperature is determined to be too high. At 150, the fan speed is increased if the inside air temperature is determined to be too low. In general, this heating function only works under the conditions where the outside temperature of the structure is greater than the inside temperature of the structure.

[0030] FIG. 4 is a flowchart of a method 160 for controlling temperature within a structure using an air purification system, in accordance with implementations described herein. The method 1 60 can be used to determine the temperature inside a structure and vary the fan speed accordingly in order to generally maintain cool inside air temperatures. As shown in FIG. 4, inside temperature is measured at 162. At 164, it is determined whether the inside temperature is at a desired temperature, or within a desired temperature range, which may be user defined or pre-programmed. If the measured inside temperature is at the desired temperature, or within the desired temperature range, the fan speed is generally not changed. However, if the inside air temperature is not at the desired temperature, or within the desired temperature range, the fan speed is changed. At 166, it is determined whether the inside air temperature is too high. At 168, the fan speed is increased if the inside air temperature is determined to be too high. At 170, the fan speed is decreased if the inside air temperature is determined to be too low. Similar to the heating function described above, the cooling function generally only works under the conditions where the outside temperature is less than the inside temperature of the structure.

[0031] The air purification system as described herein may be configured with a solar heating element such that the solar heating element may function to increase the air temperature at least before it is forced through the air purification system. In this U 2011/061964

configuration, the air purification system may provide heated air that has a greater temperature than both the inside and outside air temperatures of a structure. By way of example, the air purification system 100 may be installed on a south-facing part of a structure that receives solar radiation during the wintertime. In this configuration, the solar radiation would strike this south facing wall in the northern hemisphere generally only during the wintertime when heating the building is desired. Furthermore, the heating effect of the solar irradiated wall can be enhanced by painting the wall dark and covering the wall with a clear glass or plastic in order to trap at least some solar energy between the covering and the wall. In addition, the air purification system 100 may include a solar cover that may be placed adjacent the air intake, or louvered screen 1 16, to further enable the air purification system 100 to expel solar heated air into the structure.

[0032] in addition, some implementations of the air purification system 100 may include a re-circulation feature that can purify re-circulated air inside the structure. This recirculation feature may include an airflow loop through the air purification system 100 that enables air from inside the structure to be drawn into the air purification system 100, and then expelled back into the inside of the structure as purified air. In addition, the recirculation loop may be partially or fully closed at any time for enabling partial or full air recirculation of air within the structure. In particular, the re-circulation feature may be desirable when a large temperature differential exists between the inside and outside of the structure, or when the outside air is extremely polluted. In general, a user may manually activate the re-circulation feature, or the re-circulation feature may be automatically activated by the control circuit in response to, for example, changes in outside air temperature or quality.

[0033] Although a few embodiments have been described in detail above, other modifications are possible. Other embodiments may be within the scope of the following claims.