Patent Application
20120180784
1. Field of the Invention
This invention relates generally to improved portable heaters used in relatively small enclosures. More particularly, the invention relates to a uniquely configured propane source infrared heater for use in enclosures such as small recreational enclosures, temporary work enclosures, or vehicles. Although the invention was designed for indoor areas, it will be appreciated that it has broader applications and may be advantageously employed in a wide variety of environments without departing from the scope of the invention.
2. Description of Related Art
Gas-fired portable heaters are well known in the art and are used in multiple environments. The heater typically includes a housing having a chamber. The housing has an inlet for receiving air into the chamber. Gas is introduced into the chamber to be mixed with the air in order to complete combustion and provide an infrared heating surface. A plenum directs the heat toward a mesh screen and evenly distributes it over the surface thereof. The overall goal in designing such a unit is to achieve a radiant surface that provides even, stable heating over the entire surface.
The use of such heaters is strictly regulated for outdoor only use due to the emission of carbon monoxide. Prior designs in existing portable units are subject to a wide variety of problems. Most importantly, the prior designs are not safe or certified to operate in small recreational enclosures such as tents, truck-caps, fishing huts, trailers, vans, etc. There are a few reasons why the devices found in the prior art are not adequate to perform in such environments. First, the portable heaters that exist today operate at a high pressure generally on the order of 12 psi. Specifically, the pressure from the propane tank through a regulator is necessarily high in order to achieve adequate gas and air flow. In addition to requiring high pressure, previous designs do not have the ability to pass strict combustion requirements at a high and low firing condition and at a reduced pressure. For example, a new standard developed for this product (CSA International 4.98 US) states that “the appliance shall not produce carbon monoxide in excess of 0.010 (100 ppm) percent in a room with no air changes occurring during combustion of the amount of gas necessary to reduce the oxygen content of the room to 18 percent by volume.” In addition, they do not possess an oxygen depletion system (“ODS”) (Capreci/Part No. 21500). These shortcomings have prevented the portable heaters found in the prior art from adequately performing in small recreational and temporary work enclosures.
Existing portable units typically combust a fuel such as propane to generate heat. Propane tanks come in a variety of sizes such as a 1 pound tank that can be replaced when the propane fuel is fully consumed. To replace an empty propane tank with a full propane tank, existing heaters require the propane tank to be raised into the connection point of the heater in an upward direction from below to avoid contacting a protective structure that guards the connection between the fuel tank and the heater. In close quarters, this can be difficult to accomplish. As an alternative, the heater can be lifted to facilitate the replacement of an empty propane tank with a new tank. However, lifting the heater to install a replacement propane tank can be cumbersome, and difficult to do with one person.
Attempts have been made to alleviate at least some of the burdens associated with replacing an empty propane tank. Such attempts have typically revolved around a rotatable regulator that can be rotated in order to expose the connection point to establish a direct connection between the propane tank and the regulator. However, repeated rotation of the regulator can subject the regulator to damage from prolonged use, which in turn can cause an undesirable connection between the heater and the propane tank and hamper the ability of the heater to function properly.
Therefore, a need exists to provide a portable infrared heater capable of performing safely in small recreational enclosures and temporary work enclosures that can facilitate ready replacement of a fuel source.
This invention contemplates a new and improved burner assembly that is capable of performing safely in small recreational facilities such as tents, truck-caps, vans, fishing huts, trailers, etc.
According to the present invention, a portable heater includes an outer housing having a first or front face, a second or rear face, and two sides interconnecting the front and rear faces. An air inlet is located on the front face of the housing, preferably along a lower portion thereof. A gas supply or tank is partially enclosed and supported by the outer housing. The gas supply or tank is optionally connected with a swivel connector for ease in replacing the supply, and a stationary regulatory within the heater housing decreases the pressure of the supply. A burner venturi, having a cylindrical body extending upwardly at a slight angle, is disposed within the housing. The burner venturi also has a mouth operatively associated with a bottom end of the cylindrical body. Gas is released from the gas supply into the mouth of the burner venturi. At the same time, air is drawn into the mouth of the burner venturi from the air inlet. The air and gas mix thoroughly as they travel upwardly through the burner venturi.
Upon exiting the burner venturi, a baffle directs the air/gas mixture into a plenum to further mix, enter a rear face of a radiant surface, and then ignited on a top surface where combustion occurs. Any conventional means for initially sparking or igniting the air/gas mixture at the burner surface can be used. The burner plenum is heated to an elevated temperature and the radiant surface emits heat to the ambient environment. Combustion products are directed off a deflector shield which reduces the temperature of the products before exiting an outlet at an upper portion of the housing.
The air inlet of the present invention is advantageously designed to provide air flow along the hot burner plenum resulting in an increased velocity of air flow to the burner venturi. As the burner venturi is heated, the thermal properties result in the air/gas mixture passing upwardly through the angled burner venturi creating a chimney type effect. The chimney effect created by the present invention increases the air flow velocity into the burner venturi. In addition, the device reduces pressure from the gas supply and has the ability to satisfy combustion requirements at low fire condition.
This improved invention uses a single regulator in conjunction with two swivel connectors, preferably with check valves therein. These and other objects of the present invention will become more readily apparent from a reading of the following detailed description taken in conjunction with the accompanying drawings wherein like reference numerals indicate similar parts, and with further reference to the appended claims.
According to one aspect, the present invention provides a portable radiant heater supplied by an associated fuel source. The heater comprises a housing having a handle for transporting the heater and a plenum in the housing receives fuel from the associated fuel source and mixes the fuel with air. A burner assembly includes a radiant surface that communicates with the plenum. A regulator limits the pressure of the associated propane source to approximately eleven inches water column, and an oxygen depletion system associated with the burner assembly automatically shuts off the heater at a predetermined oxygen content. A tank fitting with a position that can be adjusted relative to the regulator facilitates the installation of the associated fuel source to the heater.
According to another aspect, the present invention provides a portable radiant heater including a regulator that is coupled to the heater at a fixed position relative to the housing. The tank fitting is optionally pivotally coupled to a bracket to pivot about a transverse axis relative to the bracket, which is itself coupled to the housing. The portable radiant heater can further include a fitting nut that is stationary relative to the housing to which a fuel-carrying conduit is coupled to establish fluid communication between the pivotal tank fitting and the regulator. The bracket can optionally be slidable along a track to be selectively withdrawn from, and introduced into the housing for exposing the tank fitting externally of the housing and facilitating installation of the associated fuel source. The fuel-carrying conduit can be a flexible fuel hose to allow the position of the slidable bracket to be adjusted during installation of the associated fuel source.
According to yet another aspect, the present invention provides a portable radiant heater comprising a plurality of tank fittings, each with a position that can be adjusted relative to the regulator to facilitate the installation of a plurality of associated fuel sources to the heater. At least one tank fitting can optionally be disposed adjacent to each lateral side of the heater and the regulator is separated approximately equidistantly from the at least one tank fitting adjacent to each lateral side. Optionally, the regulator is stationary relative to the housing and each tank fitting can be adjusted relative to the housing of the heater. Each tank fitting can also be pivotally coupled to the housing to pivot about a transverse axis relative to the housing to facilitate installation of the associated fuel source. For example, each tank fitting can be pivotally coupled to a door that can be adjusted to a closed position to conceal the associated fuel source to pivot about a transverse axis relative to the door.
According to yet another aspect, the present invention provides a portable radiant heater including a tank fitting that is releasably coupled to the heater by a releasable bracket. The releasable tank fitting can be removed from the releasable bracket while remaining coupled to a flexible fuel line that transports fuel from the associated fuel source to be delivered to the regulator.
The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof, and wherein:
Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. Relative language used herein is best understood with reference to the drawings, in which like numerals are used to identify like or similar items. Further, in the drawings, certain features may be shown in somewhat schematic form.
The Figures show a portable heater for use in confined spaces with various configurations for the positioning of the fuel source(s). Referring now to the drawings wherein the showings are for purposes of illustrating the preferred embodiment of the invention only, and not for purposes of limiting same, the Figures show a portable heating device A adapted for use in small enclosed environments. Although the present invention is designed for use in recreational enclosures and temporary work enclosures, it will be appreciated that other uses are contemplated.
The portable heater A includes a housing 10 having a front face 12, a rear face 14, and two sides 16, 18. The housing 10 is preferably manufactured to have smooth contours to prevent snagging or catching of things such as clothing, fabric, etc. A stepped recess or external cavity is formed in an upper front corner region of the left side 16 of the housing 10 for supporting a control knob or temperature controller 20. The recess provides protection against inadvertent contact and accidental changing of the temperature. The temperature controller 20 preferably has four positions: off, pilot, low, and high (not shown) although continuously variable positions for infinitely variable heating is also contemplated within the scope of this invention. Controller may incorporate a piezo spark igniter integral to controller stem rotation.
Another recess is disposed on the upper back corner of the left side 16 of the housing 10. This recess supports an igniter button 22 for activating the heater A. This recess also protects against inadvertent contact with the igniter button 22.
The heater A is supported by two elongated legs 24a, 24b laterally disposed along the outboard edges of the rear face 14 and front face 12 respectively. The legs 24a, 24b are preferably grooved providing a friction surface to contact the supporting surface and preferably extend over the entire width of the housing to provide a wide “footprint” and stable support area for the heater. In another embodiment (not shown), additional legs extending front to rear are provided beneath legs 24a, 24b to increase air flow beneath the heater. Further embodiments foresee alternative leg arrangements, such as a vertically extending leg on each of the four corners of the base of the heater, or a leg extending front to rear on either side of the base of the heater. A handle 26 is recessed from and extends from the top of the heater at an angle directed away (approximately)15° from the front face 12. The offset allows the handle to remain cool for handling by a user while the angled orientation of the handle 26 protects the user's hand from heat exiting the top of the heater while the user transports the heater. The handle 26 is optionally grooved providing an enhanced gripping surface for the user.
A shield or metal grid 30 is attached to the front face 12 of the heater to provide protection to the heater components. In addition, the shield prevents accidental contact with the hot portions of the heater front face 12. The shield is preferably made from elongated wire metal strips and peripheral pieces are received in openings 32 in the housing to secure the shield to the heater. In addition, only one screw (not shown) need be removed for access to the interior components enabling easy servicing or replacement of selected components of the heater. Two keyhole openings or recesses 34a, 34b are located on the upper portion of the back face 14 of the heater allowing the user to hang the heater in an elevated position.
An opening or air inlet 40 is disposed on a lower portion of the front face 12 of the heater for receiving and filtering air drawn into the housing. The air inlet 40 is preferably formed from a series of elongated slits 42 equispaced across the housing beneath the shield. However, any opening that adequately provides air inflow is within the scope of the present invention.
An LP (“Liquified Petroleum” or “Liquified Propane”) gas supply tank 50 is secured to and partially enclosed by the housing 10 (See
The gas supply 50 is connected through fittings and lines to a regulator which connects to a valve and orifice 56 (See
Referring again to
Also located within the housing 10 is a generally planar radiant surface 70 disposed at an angle a relative to the longitudinal axis of the heater. A rear face of the radiant surface is in communication with a cavity or plenum chamber 72. The burner plenum receives the air/gas mixture from the venturi and distributes the mixture over and through the rear face of the radiant surface. Thus, in operation, the orifice 56, attached to the gas supply, is opened releasing a fuel gas such as propane into the mouth 64 of the burner venturi 60. Associated with the orifice is a regulator that reduces the delivery pressure of the fuel gas from the tank (rated up to 150 psi) to eleven inches of water column in one stage. Thus, this portable heater operates at a significantly lower pressure than existing commercially available units. The stream of gas exiting the orifice 56 creates a vacuum effect drawing air from the air inlet 40 into the mouth 64 of the burner venturi. Propane and air are thoroughly mixed in the burner venturi 60 and plenum 72 in order to achieve complete combustion and produce a clean burning infrared heating surface. The mixture of oxygen and propane travels upward through the cylindrical body 62 of the burner venturi 60 until reaching the plenum chamber 72. To prevent the mixture of propane and oxygen from immediately exiting the plenum chamber 72, a solid baffle 76 is provided which forces the air/gas mixture downward into communication with the rear face of the radiant surface.
The radiant surface may be a burner tile or a multi-ply screens (not shown) that define a plurality of small openings which permit combustion of the air/gas mixture as it passes therethrough. A means is provided for initially sparking or igniting the mixture at the radiant surface. In the present invention a container 80 houses the pilot 82 and the igniter 84 (see
A reflector 90 extends outwardly from the top of the burner plenum 72 at an angle directed toward the top portion of the front face 12 of the housing 10. The natural convective upward path of the combustion products leads the combustion products into contact with the reflector 90. The reflector 90, in addition to directing the radiant energy output from the heater toward the front surface of the housing, also acts as a deflector and reduces the temperature of the combustion products exiting the heater which greatly reduces the chance for ignition of a combustible material if it comes into contact with the heater A. An outlet 92 is disposed near the top of the housing 10 allowing warm air to mix with combustion products and exit the device after contacting the reflector 90. In addition, a deflector 95 is disposed on the top of front face 12 which reduces the temperature of the combustion products exiting the heater which greatly reduces the chance for ignition of a combustible material if it comes into contact with the heater A.
In addition, there is an outlet or grate 94 disposed rearward of outlet 92 that communicates with the interior of the housing. It provides a continuous flow path for air (that does not enter the venturi) to flow from the inlet 40 around the rear of the plenum chamber and exit the housing rearward of the deflector. This enhances the chimney effect as described above since a large amount of ambient air is drawn into the housing, a portion used for combustion purposes and the remainder convects upwardly along the rear of the plenum and the deflector to exit via the openings 94. The air inlet 40 of the present invention is designed to encourage air flow along the back of the hot burner plenum 72, advantageously resulting in an increased velocity of air flow to the burner venturi, as well as cooling the rear housing 10. As the burner venturi 60 is heated, the thermal convection properties urge the air/gas mixture through the upwardly angled burner venturi 60 creating a chimney type effect. The chimney effect created by the present invention increases the fresh air flow velocity into the burner venturi, enabling the pressure from the gas supply 50 to be reduced, yet burn efficiently on high or low settings.
In addition to housing the pilot 82 and the igniter 84, the container 80 preferably houses an oxygen depletion system (See
The present invention significantly reduces the pressure from the propane tank in one stage. The pilot burner must operate at 11″ water column (W.C.) while the main burner may optionally operate at this same pressure although higher pressures are envisioned. This is the first portable device for indoor use that the applicant is aware of that conforms to this standard. The portable heaters that exist today all operate at high pressures (on the order of 12 psi) and do not incorporate an ODS. In addition, the present device has the ability to pass combustion requirements at a low fire condition.
In another embodiment of the invention illustrated in
As illustrated in
Within tank fitting 120 is a sealing system, made of at least one O-ring 119 in one embodiment, so as to ensure a connection that will properly seal when pressurized LP is run through the fitting and connection into inlet fuel lines 115, leading into inline regulator 166. A check-valve (not shown) is located within tank fitting 120, or swivel body receiving connector 164, to ensure a proper connection exists between fuel source 50 and tank fitting 120. If the check-valve indicates a proper connection is not made, or a leak exists, fuel will not dispense into the heater until the connection is corrected. The pressure of a check valve within tank fitting 120 also permits operation of the unit with only one fuel source 50 attached.
Pivotal movement is effected by rotatable fuel supply connection 120 feeding inlet fuel lines 115. Fuel lines 115 connect to single stationary inline regulator 166, which reduces the delivery pressure of the fuel, as shown in
In
In
It is recognized that when dual fuel source applications are discussed, it is recognized that the heat capacity of each burner need not be the same, and it is within the scope of this invention that different capacity burners are envisioned. For maximum heat control by the end-user, it is within the scope of the invention that one burner will be for “low” capacity applications and wherein the second burner will be for “high” capacity applications, and wherein the two burners can be used in combination to produce yet a higher capacity unit. For other applications, there will be two “low” capacity burners employed within one unit as well as applications where there will be two “high” capacity burners employed within the same unit. Optionally, there are applications wherein each burner (if each burner has a separate control) or a combined controller where each burner is commonly controlled) will have an associated “low”, “medium” and “high” setting to permit still further refinements in the heat provided by the device. Additionally, it is envisioned that the heating device will have a single controller and one burner, the controller/burner combination having “low”, “medium” and “high” settings. In a more expensive version of the heater, two continuously variable burners will be employed, such variability predicated by the rate at which fuel and/or air is supplied to the burners as well as the capacity of the burners, although it is envisioned that a single continuously variable burner is within the scope of this invention.
It should be noted that in embodiments of this invention in which more than one fuel source is illustrated, that the fuel sources can either be operated in tandem or individually. When operated in tandem, a mixing valve is included prior to the burner. In some embodiments of the invention, the second location of the fuel source is that of a storage capacity only, and the unit operates as previously described. It should also be noted that the handle 26 illustrated in many of the embodiments, is often optional, and that a heater which achieves portability by the incorporation of wheels 120 positioned at the bottom of the unit, better illustrated in
Alternative embodiments of the modes of attachment of the fuel supply are illustrated in
Therefore, what has been shown and illustrated is a portable heating device in which the fuel source (typically at least one, and preferably two one pound cylinders) are moveable from a first use position into a second position in which the fuel source is replaced. The at least one fuel source connects to a swivel body which connects to an associated regulator (for decreasing the pressure of the exit port gas). This mode of operation in one embodiment is effected through the incorporation of a braided gas hose which employs a sliding mechanism in which the user physically pulls the cylinder from its use position inside the housing, to a replace position outside of the housing via telescoping or sliding movement of rails. In a second embodiment, this mode of operation is effected by the fixed incorporation of the swivel body into a door in the housing within which is positioned the fuel source, thereby requiring the user to open the door with cylinder attached for replacement of the cylinder. In a third embodiment, this mode of operation is effected by removal of the fuel source from within the housing which is attached by a clamp and bracket within the housing while in a fourth embodiment, this mode of operation is effected by pivotal movement of a swivel body within a pair of U-shaped clamps having a pivot rod interposed therebetween. In yet a fifth embodiment, this mode of operation is effected by a swivel weighted clip which requires tilting of the heater prior to removal of the spent fuel cylinder.
In addition to the foregoing, a further application of the aforementioned heater encompasses the addition of a warming tray 200. Warming tray 200 is attached to the heater in any way to utilize the heat generated from the heater to warm items placed within the warming tray 200, such as food or non-flammable articles.
Tray portion 202 is supported by supporting means 204, which is also a part of the warming tray 200. Supporting means 204 are attached to the sheet or metal grid 30. Rear supporting means 206 are attached to, and within, the outlet 92. Warming tray 200 may also have (not shown) an enclosure to enclose articles placed upon/within it.
In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described.
This invention has been described in detail with reference to specific embodiments thereof, including the respective best modes for carrying out each embodiment. It shall be understood that these illustrations are by way of example and not by way of limitation.
Additionally, it will be apparent to those skilled in the art that the above illustrative embodiments of the devices and methods may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims.
This application in a continuation-in-part of and claims the benefit of U.S. Utility patent application Ser. No. 12/441,462, filed on Mar. 16, 2009, which claims priority from PCT Patent Application No. PCT/US07/07426, filed on Mar. 26, 2007, which claims priority from U.S. Provisional Application No. 60/743,757, filed on Mar. 24, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60743757 | Mar 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12441462 | Feb 2010 | US |
| Child | 13351063 | US |
