Patent Application
20090017741
1. Field of the Invention
The present invention is directed to a cap for a flue opening of a building. In particular, the present invention is directed to a cap for a flue opening having a replaceable filter in order to reduce emissions generated by a gas fired device, to extend the flue or chimney to enhance draw of exhaust, to protect from the elements, and to protect from entry of animals and debris. Additionally, the present invention provides a decorative external feature for a building.
2. Prior Art
Various types of flues and flue openings are known which are used to carry exhaust upward out of a building into the atmosphere. A wide range of chimney cap devices and chimney extensions have been designed and utilized in the past. Various chimney caps in the past have been constructed of clay or masonry. While functional and decorative, they are extremely heavy and difficult to move to a rooftop.
Lightweight, metal chimney caps have also been utilized. Examples include Assignee's U.S. Pat. No. 6,926,600, Assignee's U.S. Pat. No. 7,179,164, and Assignee's U.S. Design Pat. No. D535,010.
Various different types of gas fired devices are utilized in buildings which burn natural gas, propane, or other light hydrocarbon gases. These include gas fired fireplaces, gas fired hot water heaters, gas fired room heaters and other devices. In most instances, these devices require exhaust through a flue pipe and a flue opening through the roof of the building. While gas fired devices are fairly efficient, they emit a certain amount of carbon monoxide (CO) and unburned hydrocarbons.
Catalytic converters are known devices used to reduce the toxicity of various emissions. For example, catalytic converters have been used on automobiles for a number of decades. An example of a catalytic converter is seen in U.S. Pat. No. 3,441,381 titled “Apparatus For Purifying Exhaust Gases of An Internal Combustion Engine”. In one type of catalytic converter, carbon monoxide is converted to carbon dioxide and unburned hydrocarbons are converted to carbon dioxide and water.
Typically these devices must operate with temperatures above 600° C. for the catalysts to activate and oxidize CO and other unburned hydrocarbons. The present invention will operate at much lower temperatures (i.e. less than 200° C.).
There remains a need for a chimney cap device to reduce carbon monoxide and unburned hydrocarbon emissions generated in gas fired devices before they are exhausted into the environment.
There remains a need for a chimney cap device for a flue opening for gas fired devices having a catalytic filter.
There remains a need for a chimney cap device for a flue opening having a catalytic filter that is replaceable by accessing an opening in the chimney cap device.
There remains a need for a chimney cap device with a replaceable catalytic filter insert that is both lightweight and decorative.
The present invention is directed to a chimney cap device for a flue opening of a building. The device includes a tubular housing having an open lower end which fits over a flue pipe of the flue opening. The tubular housing also includes an open upper end opposed to the lower end.
A plurality of louver openings are provided in a lower portion of the tubular housing near the open lower end. The louver openings permit atmospheric air to enter the tubular housing and mix with exhaust gases from the flue pipe.
A removable top is attached to the open upper end of the tubular housing. The removable top includes a plurality of exit openings so that exhaust gases which pass through and out of the flue pipe will proceed upward through the tubular housing, into the removable top, and thereafter, out of the exit openings.
A metal liner is located within and spaced from the tubular housing. An opening or openings are provided through the liner adjacent the louver openings so that atmospheric air passing through the louver openings will not only pass into a space between the tubular housing and the liner, but will also pass info the tubular housing and be drawn upward toward the removable top.
The chimney cap device also includes a removable filter insert received in an optional carrier or holder having an open top and an open bottom. The carrier and filter insert are supported within the inner sleeve by a plurality of supports.
The filter insert promotes a chemical reaction wherein carbon monoxide from the exhaust gas is converted into carbon dioxide and wherein unburned hydrocarbons are converted into carbon dioxide and water. These gases and vapors are earned out the exhaust openings to the atmosphere.
The embodiments discussed herein are merely illustrative of specific manners in which to make and use the invention and are not to be interpreted as limiting the scope of the instant invention.
While the invention has been described with a certain degree of particularity, it is to be noted that many modifications may be made in the details of the invention's construction and the arrangement of its components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification.
Referring to the drawings in detail,
The chimney cap device 10 includes a tubular housing 12 which may take a number of configurations. The tubular housing has an open lower end 14 which fits over a flue pipe 20 of a flue opening of a building (not shown). The flue pipe 20 receives exhaust from a gas fired device in a building. It will be appreciated that the present invention may be utilized with a wide variety of flue openings and flue pipe configurations.
The tubular housing 12 also includes an open upper end 16 opposed to the lower end 14. The tubular housing 12 may be fabricated from flat sheet metal or other lightweight material. The tubular housing 12 may be configured so that a cross-section of the housing is in the form of a square, an octagon, a hexagon, a rectangle, a circle, or other configuration.
A plurality of louver openings 18 are provided in a lower portion of the tubular housing 12 near the open lower end 14. In one embodiment, the louver openings 18 are stamped or otherwise formed into the tubular housing 12. The louver openings 18 permit atmospheric air to enter the tubular housing and mix with exhaust gases from the flue pipe.
It will be appreciated that the present invention extends the length of the flue to enhance draw of the exhaust.
A removable top 24 is attached to the open upper end 16 of the tubular housing 12. The removable top 24 is shown apart from the device in the exploded view in
The cap device 10 also includes an inner frame and mounting assembly 22 attached near the open lower end 16 of the tubular housing 12. The inner frame and mounting assembly 22 includes an anchoring and leveling mechanism to anchor the inner frame and mounting assembly to the building (not shown). In particular, the anchoring and leveling mechanism may be used to anchor the inner frame and mounting assembly to a chimney or to a roof 40.
One embodiment of an inner frame and mounting assembly is disclosed in detail in Assignee's U.S. Pat. Nos. 7,179,164 and 6,926,600, which are incorporated herein by reference.
The removable top 24 includes a pyramidal upper section 30. An optional heat deflector 32 beneath the pyramidal upper section 30 assists in creating turbulence in the exhaust gases and air. The turbulence assists in directing the exhaust gases and air out of the exit openings 26. An optional rain guard 34 may be installed inside of the removable top 24 to discourage rain from passing through the exit openings 26 into the tubular housing.
A metal liner 50 is located within and spaced from the tubular housing 12. An opening or openings are provided through the liner 50 adjacent the louver openings 18 so that atmospheric air passing through the louver openings 18 will not only pass into the space between the tubular housing 12 and the liner 50, but will also pass into the tubular housing 12 and be drawn upward toward the removable top. The air drawn into the space between the tubular housing 12 and the liner 50 acts to insulate the tubular housing 12 from the heat of the exhaust.
The chimney cap device 10 also includes a removable filter insert 60. The filter insert 60 is received into an optional carrier or holder 62 having an open top and bottom.
Once the top 24 has been removed from the device 10, the carrier 62 and its accompanying filter 60 may be removed.
Arrows 70 in
The filter insert 60 promotes a chemical reaction wherein carbon monoxide from the exhaust gas is converted into carbon dioxide and wherein unburned hydrocarbons are converted to carbon dioxide and water which are carried out the exit openings. Carbon monoxide combines with oxygen to form carbon dioxide and unburned hydrocarbons combine with oxygen to form carbon dioxide and water.
Various types of filter inserts may be employed. One type of catalytic converter includes a core or substrate fabricated from a ceramic honeycomb. The ceramic honeycomb has a series of thin walled rectangular channels which permit passage of gases therethrough. The openings are greater than the cross-section of the area of the flue pipe.
A washcoat is applied to the substrate core which may be a mixture of silicon and aluminum. The washcoat forms a rough, irregular surface. An oxidation catalyst is added to the washcoat in suspension before application to the core. The catalyst may be chosen from a variety of metal ingredients such as platinum, rhodium and/or palladium. Other types of metals might also be employed. The catalyst may be designed to operate at maximum efficiency between 140° F. (60° C.) and 300° F. (149° C.).
When in operation, the exhaust gases from the gas fired appliance, such as a gas fired fireplace, pass from the fireplace into and through the flue pipe 20. The exhaust gases mix with incoming atmospheric air entering through the louver openings 18 of the tubular housing. The gas mixture contacts the catalyst on the filter insert 60 whereby the carbon monoxide and the unburned hydrocarbons are oxidized to carbon dioxide (CO2) and water (H2O). The purified gases are thereafter discharged into the removable top 24 and out of the exhaust openings.
Periodically, the removable top 24 may be separated from the device 10 by removing fasteners 58 shown exploded in
It is estimated that more than 20 percent (20%) of the carbon monoxide and unburned hydrocarbons may be destroyed through use of the present invention.
The preferred embodiment described herein applies to a passive catalytic converter, however, an electrical heating element may be added to the filter insert to raise the operating temperature.
The present invention might also be modified to include a sensor in or adjacent the filter insert to sense if the filter becomes plugged. In that event, a visual and/or audible alarm wired to the sensor would be triggered.
Whereas, the present invention has been described in relation to the drawings attached, hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.
