A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
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The present invention relates generally to cast iron wood stoves (i.e., heaters).
Metal castings (e.g., cast iron) are used to make single burn rate, single chamber wood burning stoves. Fuel burn rates in these stoves are typically relatively high burn rates (i.e., in excess of 5 kilograms per hour). These stoves are cheap to produce, hot to the touch, and relatively inefficient. Thus, these stoves are generally used only for recreational or occasional use applications (e.g., in a hunting cabin or in a shop). Many modern stoves burn processed wood pellets instead of raw wood and have complicated airflow management systems for variable burn rates and high fuel efficiency. Until March 2015, these single chamber, single burn rate stoves with fuel consumption rates in excess of 5 kg/hr were exempt from emissions limitations in the United States. They are no longer exempt, but the same requirements of simplicity and having the capacity to burn raw wood remain.
What is needed then is an improved single burn rate, single chamber wood burning stove.
Aspects of the present invention provide a single burn chamber, single burn rate wood stove with managed airflow which reduced emissions to within accepted limits. One aspect of the present disclosure is a single combustion chamber, single burn rate solid fuel combustion heating appliance including a firebox having a top and a side; and a first secondary air manifold extending longitudinally within the firebox, wherein the first secondary air manifold is positioned proximate the top and the side of the firebox.
Reference will now be made in detail to optional embodiments of the invention, examples of which are illustrated in accompanying drawings. Whenever possible, the same reference numbers are used in the drawing and in the description referring to the same or like parts.
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.
To facilitate the understanding of the embodiments described herein, a number of terms are defined below. The terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity, but rather include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as set forth in the claims
As described herein, an upright position is considered to be the position of apparatus components while in proper operation or in a natural resting position as described herein. That is, an upright position of a wood stove is that of a wood stove installed on a level platform (e.g., floor) with the feet on the platform and flue above the feet. Vertical, horizontal, above, below, side, top, bottom and other orientation terms are described with respect to this upright position during operation unless otherwise specified. The term “when” is used to specify orientation for relative positions of components, not as a temporal limitation of the claims or apparatus described and claimed herein unless otherwise specified. The terms “above”, “below”, “over”, and “under” mean “having an elevation or vertical height greater or lesser than” and are not intended to imply that one object or component is directly over or under another object or component.
The phrase “in one embodiment,” as used herein does not necessarily refer to the same embodiment, although it may. Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
Referring to
Air is introduced to the firebox 14 through two manifolds: a primary air manifold 28 and a secondary air manifold 30. Both secondary and primary air 31a and 31b are pulled into the stove through natural draft established by the flue 32 and chimney 34 connected to the stove 10. Primary air enters through at least one primary air intake 36 and travels into the primary air intake manifold 28 where it is distributed through a series of orifices in the primary air intake manifold 28 and through an opening 38 at the bottom of the primary air intake manifold 28. In some embodiments, the primary air intake manifold 28 can be a singular hollow passageway through which air from primary air intake 36 can pass and exit out of the opening 38 in the bottom of the primary air intake manifold 28. The primary air is the primary source that feeds the fire in the firebox 14. In one embodiment, the front door 16 of the wood stove 10 includes a primary air intake 36 including slits or openings in fluid communication with an interior of the primary air intake manifold 28. The primary air intake manifold 28 then directs the air downward toward a bottom of the firebox 14 through bottom opening 38 in the primary air intake manifold 28. In one embodiment, the primary air intake manifold 28 can be made from stamped steel.
In some embodiments, the firebox 14 has a front defined by a door 16 having an upper half 16a and a lower half 16b, said door 16 having at least one opening 36 therethrough in the upper half 16a of the door; and the at least one opening 36 is configured to receive primary combustion air 31a from outside the solid fuel combustion appliance 10. The door 16 can further include a primary air intake manifold 28 attached to a firebox side 16c of the door 16. The primary air intake manifold 28 is configured to receive the primary combustion air 31a from the outside of the solid fuel combustion appliance 10 and provide the received primary combustion air 31a to the lower half 16b of the door 16. In some embodiments, the at least one opening 36 can include a plurality of openings spaced laterally across the door 16 and configured to receive primary combustion air 31a from the outside of the fuel combustion appliance, such that the primary combustion air 31a is substantially equalized laterally across the firebox 14. In some embodiments, the primary air orifices 36 in the door of the wood stove 10 are in an upper half of the door 16, and the primary air intake manifold 28 extends to or below the middle of the door 16, or extends adjacent the lower half 16b of the door 16.
Another aspect of the present disclosure is a single combustion chamber, single burn rate solid fuel combustion heating appliance 10 including a firebox 14 having a top 26 and a side 22; and a first secondary air manifold 46a extending longitudinally within the firebox 14, wherein the first secondary air manifold 46 is positioned proximate the top 26 and the side 22 of the firebox 14.
In some embodiments, the side 22 is a first side and the firebox 14 further comprises a second side 24 opposite the first side, and wherein the solid fuel combustion heating appliance 10 further comprises a second secondary air manifold 46b extending longitudinally within the firebox 14, wherein the second secondary air manifold 46b is positioned proximate the top 26 and the second side 24 of the firebox 14. In other words, the secondary air manifolds 46 can be positioned adjacent opposing top corners 48 of the firebox 14. The opposing top corners 48 of the firebox 14 in which the secondary air manifolds 46 are positioned in can also be described as the upper lateral corners or edges of the firebox 14
In some embodiments, the firebox 14 includes a bottom 20 comprising a metal layer. The heating appliance 10 can further include a secondary air baffle 42 extending longitudinally below the bottom 20 of the firebox 14 of the heating appliance 10. The secondary air baffle 42 is configured to direct secondary air from a front of the heating appliance to a rear of the heating appliance. In some embodiments, the secondary air baffle 42 is or can act as a bottom heat shield of the solid combustion heating appliance 10. In other embodiments, the heating appliance 10 can further include a bottom heat shield 43 below the secondary air baffle 42. In such embodiments where the bottom 20 of the firebox includes a metal layer, heat from the firebox can be transferred or radiated from the bottom 20 of the firebox 14 such that secondary air 31b air being directed from the front of the heating appliance 10 to the back of the heating appliance 10 can be preheated.
In other embodiments, the firebox 14 includes a bottom 20 including a metal layer and an insulating layer. In some embodiments, the insulating layer can include a fireboard or other suitable insulating material. In such embodiments, the insulating layer can protect and insulate air being directed from the front of heating appliance to the back of heating appliance from the heat generated by firebox 14 such that secondary air 3 lb can remain at a relatively low temperature.
The bottom 20 of the firebox 14 and the secondary air baffle 42 can form a secondary air intake 40. Secondary air 31b is drawn in through the secondary air intake 40 and along the bottom 20 of the heating appliance 10, the secondary air 31b being directed by the secondary air baffle 42 toward the back of the heating appliance 10. In other embodiments, secondary air baffle 42 may include a top and bottom panel positioned beneath the bottom surface 20 of the shell 12, such that secondary air 31b passes between the top and bottom panels of the secondary air baffle 42. In some embodiments, one or more of the top and bottom panels of the secondary air baffle 42 can include a heat shield or be made of a heat resistant material which can protect and insulate secondary air 3 lb directed by secondary air baffle 42 toward the rear of heating appliance 10 from the heat produced by the firebox 14, such that secondary air 31b can pass through the secondary air baffle 42 and remain at a relatively low temperature. In such embodiments, secondary air intake 40 can be defined by the top and bottom panels of secondary air baffle 42.
The heating appliance 10 can further include a at least one or a first secondary air tube 44a in fluid communication with the secondary air intake 40 and the first secondary air manifold 46a. The secondary air 31b is directed by the secondary air baffle 42 from the secondary air intake 40 and into the first secondary air tube 44a, the first secondary air tube 44a providing the secondary air 3 lb to the first secondary manifold 46a. The first secondary air tube 44 can extend up the back of the firebox 14, the secondary air tube 44 extending between the secondary air baffle 42 and the first secondary air manifolds 46a. As such, the first secondary air tube 44a can be configured to transmit secondary air 3 lb moved to the rear of the heating appliance 10 by the secondary air baffle 42 to the first secondary air manifold 46a. The secondary air 31b passes from the first secondary air tube 44a into the first secondary air manifold 46a, where the secondary air 31b is dispersed from the first secondary air manifold 46a into an upper portion of the firebox 14.
In some embodiments, including second secondary air manifold 46b, the heating appliance can further include a second secondary air tube 44b in fluid communication with the secondary air intake 40 and the secondary air manifold 46b. In other words, the heating appliance 10 can include a pair of secondary air tubes 44, each secondary air tube 44 fluidly communicating the secondary air intake 40 and a corresponding secondary air manifold 46a or 46b. The secondary air manifolds 46a and 46b can both extend longitudinally (i.e., front to back) inside the firebox 14. In some embodiments, the first secondary air tube 44a can be integral with the first secondary air manifold 46a, and the second secondary air tube 44b can be integral with the second secondary air manifold 46b. In some embodiments, a single rear secondary baffle can extend between the secondary air baffle 42 and the secondary air manifolds 46a and 46b, the rear secondary baffle supplying air to both secondary air manifolds 46a and 46b. In some embodiments, the rear secondary baffle forms a rear of the firebox 14.
A series of orifices 50 in the secondary air manifolds 46a and 46b introduce the secondary air 31b into the firebox 48 below the top 26 of firebox 14. The first secondary air tube 44a has a plurality of secondary air orifices 50 configured to direct secondary air toward the second side 24 of the firebox 14. The second secondary air tube 44b has a plurality of secondary air orifices 50 configured to direct secondary air toward the first side 22 of the firebox 14. In one embodiment, all of the orifices 50 are oriented in a plane substantially parallel to the bottom 20 of the firebox 14, and directly face the opposing secondary air manifold 46. That is, the orifices 50 are positioned on an interior, lateral side or portion of each of the secondary air manifolds 46. The top 26 of firebox 14 makes the secondary air 31b mix with the hot gasses produced by the fire in the firebox 14 and burn off excess emissions generated from the solid fuel (wood or wood pellets) burning in the firebox 14.
In some embodiments, the first secondary air tube 44a does not have any secondary air orifices such that the first secondary air tube 44a is configured to conduct secondary air only from the secondary air intake 40 into the first secondary air manifold 46a. Similarly, in some embodiments, the second secondary air tube 44b does not have any secondary air orifices such that the second secondary air tube 44b is configured to conduct secondary air only from the secondary air intake 40 into the secondary air manifold 46b.
The heating appliance further comprises an upper baffle 51 extending between the first secondary air manifold 46a and the second secondary air manifold 46b. The upper baffle 51 is configured to form an exhaust path between the upper baffle 51 and a top of the heating appliance 10. The heating appliance 10 further comprises a flue 32 extending from a top of the heating appliance 10 proximate the rear of the heating appliance 10. The exhaust path conducts exhaust gases toward the flue 32 from adjacent the front of the firebox 14 and top 26 of the firebox to the flue 32. In some embodiments, the upper baffle 51 can form the top 26 of the firebox 14, such that the upper baffle 51 is supported by or affixed to the first and second secondary air manifolds 46a and 46b. In one embodiment, the upper baffle 51 is stamped steel and is integral with the secondary air manifolds 46.
A ceramic fiber blanket or ceramic insulation layer 52 rests on top of or is attached to a top surface of the upper baffle 51. The ceramic fiber blanket 52 insulates the upper baffle 26 and serves to increase the temperature in the firebox 14 as the combustion processes occur. After the secondary air 31b has reacted with the hot gasses in the upper portion of the firebox 14, the gases move forward toward the door 16 of the stove 10 and turn above the upper baffle 26 near the front of the stove 10. The exhaust gases then continue along the top of the stove 10 along the upper baffle 26 toward the back of the stove 10 and exit the wood stove 10 through the flue outlet 32 through the upper surface 23 of the cast shell 12 of the wood stove 10. As the gases exit through the flue outlet 32 they are slowed down by a damper 54.
In some embodiments, as shown in
The combination of a bottom air baffle 42, secondary air tubes 44, secondary air manifolds 46, primary air manifold 28, upper baffle 26, and ceramic insulation blanket 52 allows this single chamber, single burn rate wood stove to achieve improved emissions levels that are emissions requirements compliant.
This written description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
It will be understood that the particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention may be employed in various embodiments without departing from the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.
All of the compositions and/or methods disclosed and claimed herein may be made and/or executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of the embodiments included herein, it will be apparent to those of ordinary skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.
Thus, although there have been described particular embodiments of the present invention of a new and useful SINGLE BURN RATE SOLID FUEL HEATING APPLIANCE WITH MANAGED AIRFLOW it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.
This application is a non-provisional of U.S. patent application Ser. No. 62/175,954 filed Jun. 15, 2015 entitled CAST STOVE WITH MANAGED AIRFLOW which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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62175954 | Jun 2015 | US |