Gas-Fired Portable Unvented Infrared Heater

Abstract

A portable radiant heater supplied by an associated fuel source comprises a housing having a handle for transporting the heater. 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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]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.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]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.[0004]2. Description of ...

AI Technical Summary

Benefits of technology

[0011]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.

[0012]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.

[0013]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.

[0015]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.

[0016]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.

Problems solved by technology

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.

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.

In close quarters, this can be difficult to accomplish.

However, lifting the heater to install a replacement propane tank can be cumbersome, and difficult to do with one person.

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.

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