Patent Publication Number: US-2021172652-A1

Title: Transverse fuel fired forced air space heater

Description:
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. 
     CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims priority to and hereby incorporates by reference in its entirety U.S. Provisional patent Application No. 62/940,148 entitled “TRANSVERSE FUEL FIRED FORCED AIR SPACE HEATER” filed on Nov. 25, 2019. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO SEQUENCE LISTING OR COMPUTER PROGRAM LISTING APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to space heaters. More particularly, this invention pertains to fluid fuel combustion appliances as forced air space heaters. 
     A fluid fuel (e.g., propane or natural gas) based forced air heater or space heater typically uses a fan (e.g., blower) for pushing ambient air through and around a combustion chamber. As the air flows around and through the combustion chamber, fuel (e.g., propane) is introduced into the air stream, and the air/fuel mixture is ignited by an ignition source. The air stream (i.e., exhaust gases and blower air) is exhausted into the space to be heated. Most of these propane space heaters are tube style heaters such that the heated air is exhausted through the longitudinal end of the tube opposite the intake end of the combustion chamber directly into the area to be heated. While forced air heaters are a practical source of temporary heating in outdoor or unfinished construction heating spaces, the combustion chamber of a typical portable forced air heater is open to heated space. This open-ended combustion chamber exposes an open flame to the area being heated which is a fire hazard, particularly in construction and shop environments where combustible materials are necessarily present. 
     BRIEF SUMMARY OF THE INVENTION 
     Aspects of the invention provide a fuel (e.g., fluid fuel such as propane or natural gas) fired portable forced air heater having non-linear air flow and an enclosed combustion chamber. Air intake is longitudinal, and heated air output is axial (i.e., perpendicular to the longitudinal axis). In this way, aspects of the invention eliminate an exposed open flame in forced air fluid fuel fired space heaters. Additionally, features of the portable heater such as feet and handles are shaped so as to provide appropriate safety clearances for the heater, and the air flow path of the heater keeps a housing of the heater near room temperature. 
     In one embodiment, a fuel fired forced air heater includes a housing, a combustion chamber, and a blower. The combustion chamber and the blower are within the housing. The housing extends longitudinally. The housing includes a first end including an air intake, and a first side including a heat discharge. The combustion chamber is configured to receive fuel and burn the fuel therein. The blower is configured to receive air from the air intake, pass the air across an outside surface of the combustion chamber, and exhaust the air from the heater via the heat discharge. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is an isometric view of a fuel fired forced air heater according to one embodiment of the invention. 
         FIG. 2  is a top perspective view of the fuel fired forced air heater of  FIG. 1 . 
         FIG. 3  is an end perspective view of the fuel fired forced air heater of  FIG. 1 . 
         FIG. 4  is a side perspective view of the fuel fired forced air heater of  FIG. 1 . 
         FIG. 5  is an end perspective view of the intake end of the fuel fired forced air heater of  FIG. 1 . 
         FIG. 6  is a perspective cutaway view of the heater of  FIG. 4  from a first end of the heater along the line B. 
         FIG. 7  is a perspective cutaway view of the heater of  FIG. 4  from a second end of the heater along the line C. 
         FIG. 8  is a perspective cutaway view of the heater of  FIG. 4  from a first side of the heater along the line A. 
         FIG. 9  is a side perspective view of a second end of the combustion chamber of the heater of  FIG. 4 . 
     
    
    
     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. 
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 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. As used herein, the upright orientation of the heater is sitting on a level surface with the bottom down and top up such that the heater is ready for operation or may be in operation. 
     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 operator input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. 
     Referring to  FIGS. 1-9 , a forced air heater  100  includes an enclosed combustion burner  101 , a housing  103 , and a series of feet  105 ,  107  or handles  109 ,  111  about the housing  103 . The housing  103  is generally elongated along a longitudinal axis. The enclosed combustion chamber  101  eliminates exposure of the combustion flame to the outside environment (i.e., space to be heated by the heater  100 ). The combustion chamber  101  including an enclosed burner is at the opposite end  115  of the heater from the air intake  113  and separate from the room air fan  117  and air outlet  119  of the heater  100 . Containing combustion remotely from the room airflow requires construction of space around the combustion chamber  101  and heater housing  103  to remove heat from surrounding, potentially combustible, materials that might come in contact with the heating appliance  100  when operating. 
     The heater  100  includes a series of feet  105 ,  107  and handles  109 ,  111  extending from the housing  103  of the heater  100  to create a zone of space around the housing  103  of the appliance  100  to remove and prevent contact of the heater housing  103  with potentially combustible materials. This series of feet  105 ,  107  and handles  109 ,  111  utilizes specific geometry to create a safe zone of combustion (i.e., an area free from combustion about the housing  103 ) and to orient the exhaust or room air output  119  upward from a plane (i.e., a plane defined by a surface upon which the heater  100  is sitting in an upright position). 
     The fuel fired portable forced air heating appliance  100  utilizes crosswise or non-axial blower system to exhaust heated air through the non-axial front face  121  of the appliance  100 . The fuel fired portable forced air heating appliance  100  utilizing feet  105 ,  107  and handles  109 ,  111  to lift the base of the appliance housing  101  away from a surface that the appliance  100  rests on to protect the surface from exposure to heat. Similarly, feet  105 ,  107  and handles  109 ,  111  protect the outside environment from foreign objects resting on a top or sides of the appliance  100  and exposing foreign objects to heat from the appliance  100 . 
     In one embodiment, a fuel fired portable forced air heating appliance  100  includes a primary combustion chamber  101  offset from axial airflow where ambient air is inducted through the axial end  113  of the appliance  100  to the combustion chamber  101  and then exhausted through a cross axial opening  119  in the front face  121  of the appliance  100 . In one embodiment, a foot  105 ,  107  and handle set  109 ,  111  is oriented either longitudinally (along the axis) or cross-longitudinally (perpendicular to the axis) to create clearances for the housing  103  of the heating appliance  100  to combustibles proportional to the temperatures generated by the enclosed combustion. In one embodiment, combustion is fully enclosed within the appliance  100  preventing open flame from combustion from being exposed to the outside environment. In one embodiment, airflow is driven by a blower system  117  mounted perpendicularly to the main axis of the heating appliance  100 . In one embodiment, airflow is non-linear where ambient air enters the appliance on one axis (e.g., the longitudinal axis) but exhausts on an axis perpendicular to air input axis. 
     In one embodiment, the fuel fired forced air heater  100  includes the housing  103 , the combustion chamber  101 , and the blower  117 . The housing  103  extends longitudinally, and includes a first end  113 , and a first side  121 . First end  113  includes an air intake  131 . In one embodiment, the air intake  131  is a grate (e.g., screen or grill). The first side  121  includes the heat discharge or air outlet  119 . In one embodiment, the housing  103  further includes a top  135 , a bottom  137  a second side  139  opposite the first side  121 , and the second end  115  opposite the first end  113 . In one embodiment, the top  135  bottom  137 , second end  115 , and second side  139  are substantially airtight such that substantially all air entering the housing  103  enters through the air intake  131  of the first end  113  of the housing, and all air exiting the housing  103  exits through the heat discharge  119  in the first side  121  of the housing  103 . 
     The blower  117  is enclosed within the housing  103 . The blower  117  is configured to receive air from the air intake  131 , passed the air across an outside surface of the combustion chamber  101 , and exhaust the air from the heater  100  via the heat discharge  119 . In one embodiment, the blower  117  is further configured to draw the air from the air intake  131  across an outside body  133  of the blower  117  before exhausting the air from the heater  100  via the heat discharge  119 . In one embodiment, the blower  117  is between the combustion chamber  101  and the first end  113  of the housing  103 . In one embodiment, the combustion chamber  101  is between the blower  117  and the second end  115  of the housing  103 . In one embodiment, the blower  117  is a centrifugal squirrel cage blower or fan. 
     The combustion chamber  101  is enclosed within the housing  103 . The combustion chamber  101  is configured to receive fuel and burn the fuel therein. In one embodiment, the combustion chamber  101  includes a first end  141 , and a second end  143  longitudinally opposite the first end  141  of the combustion chamber  101 . The first end  141  of the combustion chamber  101  includes a plurality of holes  145  therethrough. The second end  143  of the combustion chamber  101  also includes a plurality of holes  147  therethrough. The first end  141  of the combustion chamber when one is closer to the first end  113  of the housing  103  than the second end  143  of the combustion chamber  101 . The plurality of holes  147  through the second end  143  of the combustion chamber  101  form and air intake for the combustion chamber  101 , and the plurality of holes  145  through the first end  141  of the combustion chamber  101  form an outlet for the combustion chamber  101 . In one embodiment, the first end  141  of the combustion chamber  101  is sealed to an air intake of the blower  117 . In one embodiment, the heater  100  further includes a fuel orifice  150  located in the second end  143  of the combustion chamber  101 . In one embodiment, the heater  100  further includes an ignition source  151  located in the second end  143  of the combustion chamber  101  adjacent the fuel orifice  150 . In one embodiment, the ignition source  151  is a pilot. In one embodiment, the ignition source  151  is a pilot light and a spark ignition system. In one embodiment, the pilot light has a thermocouple  160  configured to shut off fuel to the pilot light when a temperature of the thermocouple falls below a predetermined limit. In one embodiment, the heater  100  further includes a thermal limit switch  155  at the second end  143  of the combustion chamber  101 . The thermal limit switch  155  is configured to shut off fuel to the orifice  150  when the temperature at the second end  143  of the combustion chamber  101  exceeds a predetermined limit. 
     In one embodiment, the heater  100  further includes an adjustable fuel regulator  161  configured to provide a user to determined fuel flow rate to the fuel orifice  150  in the combustion chamber  101  of the heater  100 . 
     In one embodiment, in use the first end  141  of the combustion chamber  101  is sealed to the intake of the blower  117  such that the air enters the air intake  131  in the first end  113  of the housing  103 , passes across an outside body  133  of the blower  117 , then across an outside surface  170  of the combustion chamber  101 , then through the plurality of holes  147  in the second end  143  of the combustion chamber  101 , then through the plurality of holes  145  in the first end  141  of the combustion chamber  101  into the intake of the blower  117 , and then through the blower  117  and out of the heater  100  via the heat discharge  119  in the first side  121  of the housing  103  of the heater  100 . This air flow path keeps the housing  103  at about room temperature while also cooling the outside surface  170  of the combustion chamber  101  and outside surface  133  of the blower  117 . 
     In one of embodiment, the heater  100  further includes a first foot  105  extending downward from the first side  121  of the housing  103  and outwardly from the bottom  137  of the housing  103  to set the housing  103  off of a surface supporting the heater  100 . A second foot  107  extends downward from the second side  139  of the housing  103  and outwardly from the bottom  137  of the housing  103  to set the housing  100  off of the surface supporting the heater  100 . The first foot  105  and the second foot  107  each extend longitudinally along the housing  103  of the heater  100 . In one embodiment, the first foot  105  is longer than the second foot  107  such that the first side  121  of the housing  103  of the heater  100  and the heat discharge  119  are slightly angled up from the surface. In one embodiment, the heater  100  further includes the first handle  109  extending upwardly from the top  135  of the housing  103  and outwardly from the first side  121  of the housing  103 . The heater  100  further includes the second handle  111  extending upwardly from the top  135  of the housing  100  and outwardly from the second side  139  of the housing  100 . The first handle  109  and second panel  111  each extend longitudinally along the housing  103 . The first foot  105 , second foot  107 , first handle  109 , and second handle  111  cooperate to space the first side  121 , second side  139 , top  135 , and bottom  137  of the housing  103  of the heater  100  a predetermined distance from any flat surfaces adjacent the heater  100 . 
     As used herein, liquid fuel or fluid fuel may be liquid or gas (e.g., natural gas, propane, or camp gas in any liquid or gaseous state). 
     In one embodiment, the combustion chamber forms an air to air heat exchanger. In one embodiment, the combustion chamber receives combustion air from the blower motor and exhausts the combustion air at a point other than the heat discharge of the housing. In one embodiment, the combustion chamber receives combustion air from the air intake and exhausts combustion air via the heat discharge of the housing via a venturi. 
     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 TRANSVERSE FUEL FIRED FORCED AIR SPACE HEATER it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following