Field of the Invention

[0001] The present invention relates to combustion burner devices, in particular, to an ethanol burner.

Background

[0002] Natural gas, propane, and other fossil fuels are widely used in combustion burners in a variety of applications, including food preparation and space heating. However, recent efforts to move away from the use of fossil fuels to alternative, renewable fuel sources has created the need for new devices to replace traditional gas burners.

[0003] Ethanol fuel has been widely acknowledged as a renewable alternative to fossil fuels and has been used in certain sectors, for example, as an additive to gasoline. However, the adoption of ethanol as a fuel for combustion burners has been slow, due to the limitations of existing devices, including low heat output that is inadequate for many commercial or industrial applications. Accordingly, there is a need for improved combustion burners, capable of using ethanol as a combustion fuel, so as to reduce the use of fossil fuels in combustion burners.

Summary of the Invention

[0004] An ethanol burner, according to the present invention, has a temperature-controlled vaporization chamber with a temperature probe and a controllable heat source, configured to maintain the temperature of liquid ethanol fuel therein between 160°F and 180°F. A burner is connected to the vaporization chamber by a mixing chamber. The mixing chamber is connected to the vaporization chamber by a fuel intake and has an air intake located between the vaporization chamber and the burner. The vaporization chamber contains liquid ethanol fuel that is heated by the heat source to the desired temperature to produce ethanol fuel vapour, which is then supplied to the burner, via the mixing chamber.

[0005] In one embodiment, the temperature of the liquid ethanol fuel in the vaporization chamber is maintained at about 171 °F. [0006] In another embodiment, the controllable heat source is an electric heating element.

[0007] In another embodiment, the vaporization chamber is between 250 mL and 1L in size. Optionally, the vaporization chamber may be connected to a liquid fuel supply to receive liquid ethanol fuel therefrom.

[0008] In another embodiment, the air intake is a passive intake. Alternatively, the air intake may be a forced air intake.

[0009] In another embodiment, the liquid ethanol fuel in the vaporization chamber is pre heated by the heat of the flame from the burner.

Brief Description of the Drawings [0010] In order that the invention may be more clearly understood, a preferred embodiment thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which:

[0011] Figure 1 is a schematic side view of the ethanol burner of the present invention. Description of the Invention

[0012] The ethanol burner, according to the present invention, heats liquid ethanol fuel in a temperature-controlled vaporization chamber and mixes ethanol fuel vapour with air to create a combustion mixture, which is supplied to a burner for combustion. [0013] As shown in Figure 1, the ethanol burner has a temperature-controlled vaporization chamber 1, a mixing chamber 2, a burner 3, a temperature probe 4, and a controllable heat source 5. The vaporization chamber 1 is connected to the burner 3 by the mixing chamber 2. The vaporization chamber 1 contains liquid ethanol fuel, which is heated by the controllable heat source 5 to produce ethanol vapour fuel. The ethanol vapour fuel enters the mixing chamber 2 from the vaporization chamber 1 by way of a fuel intake 6 at the connection between the mixing chamber 2 and the vaporization chamber 1.

[0014] The heat source 5 is preferably an electric heating element that extends into the vaporization chamber 1. The heating element may be a loop, coil, or ribbon made of a resistant metal, such as ni chrome. Alternatively, other types of ceramic, semiconductor, or thick fdm heating elements may be used. For smaller applications, preferably, the heat source 5 is powered by a solar power cell or a wind turbine.

[0015] The heat source 5 may instead be a solar concentrator, which pre-heats the liquid ethanol fuel before it enters the vaporization chamber 1. Alternatively, the liquid ethanol fuel may be pre-heated by the heat of the flame from the burner 3. It is also possible to combine either form of pre-heating with an electric heating element, in the event that the pre-heating is insufficient to achieve or maintain the desired temperature in the vaporization chamber 1. For example, where the liquid ethanol fuel is pre-heated by the flame from the burner 3, a heating element may still be required on start-up to initially heat the liquid ethanol fuel in the vaporization chamber 1.

[0016] Once in the mixing chamber 2, the ethanol vapour fuel mixes with air, which is supplied to the mixing chamber 2 by an air intake 7. This results in a combustion mixture, which is supplied from the mixing chamber 2 to the burner 3 for combustion. Typically, the burner 3 is a ring burner with a circular gas manifold, having a plurality of ports 8 through which the combustion mixture is released. Preferably, the ports 8 have an opening with a diameter of not less than 1 mm. The burner 3 may be any configuration of gas burner, depending on the desired application. Typically, the burner 3 is made of cast iron, steel, or stainless steel.

[0017] The vaporization chamber 1 is a temperature controlled tank or reservoir for liquid ethanol fuel that heats the liquid ethanol fuel to produce ethanol vapour fuel. The temperature probe 4 and the heat source 5 operate together to monitor and control the temperature of the liquid ethanol fuel in the vaporization chamber 1. The temperature is raised to between 160 °F and 180 °F in order to increase the rate of evaporation of the liquid ethanol fuel in the vaporization chamber 1. The boiling point of pure ethanol, at atmospheric pressure is 173.1 °F, so it is preferable to maintain the temperature of the liquid ethanol fuel in the vaporization chamber 1 slightly below the boiling point, at about 171 °F. At this temperature, the vaporization chamber 1 maintains an optimum rate of evaporation to provide ethanol vapour fuel to the mixing chamber 2. Preferably, a voltage regulator is used to control the power supplied to the heat source 5, so as to control the temperature. [0018] The vaporization chamber 1 may be connected to a tank or other supply of liquid ethanol fuel. Alternatively, the vaporization chamber 1 may, itself, function as a fuel tank, for example, in portable embodiments of the ethanol burner. In larger systems, it is preferable to heat a small volume of liquid ethanol in the vaporization chamber 1, such as between about 250 mL and 1 L, and to supply additional liquid ethanol fuel to the vaporization chamber 1, as it is consumed during operation from a separate fuel tank or supply.

[0019] The mixing chamber 2 includes a fuel intake 6 to draw ethanol vapour fuel from the vaporization chamber 1 and an air intake 7 to draw air from around the ethanol burner. The mixing chamber 2 may be any suitable type of mixing chamber, such as a fuel delivery tube with an air intake tube attached midway between the vaporization chamber 1 and the burner 3 at an angle of about 45°, as shown in Figure 1. Regardless of the configuration, ethanol vapour fuel and air combine in the mixing chamber 2 to produce a combustion mixture that is supplied to the burner 3. The mixing chamber 2 also acts as a delivery tube to supply the air-fuel combustion mixture to the burner 3 for combustion. [0020] The air intake 7 may be a passive intake or a forced air intake. Preferably, a variable- speed fan 9 on the air intake 7 provides an adjustable flow of air for the combustion mixture. The variable-speed fan 9 may be a variable fan blade unit, a variable air injection system supplied by Exair Corp., or another suitable forced air device.

[0021] In a preferred embodiment, the ethanol burner is configured as a portable, stand-alone unit, suitable for camping or other similar activities. In this type of unit, a tip over shut off valve 10 on the mixing chamber 2 prevents the flow of vapour or liquid ethanol fuel to the burner 3 in the event that the unit is tipped over. The tip over shut off valve is preferably positioned in the mixing chamber 2 between the fuel intake 6 and the air intake 7, so that liquid ethanol fuel does not flow out of the air intake 7 in the event the ethanol burner is tipped over. [0022] Other safety features may also be provided, such as a safety shut off solenoid valve 11 on the mixing chamber 2 and a flame sensor 12 adjacent the burner 3, which will shut off the flow of ethanol vapour fuel to the burner 3 if the flame sensor 12 detects that the flame has gone out. Additionally, a liquid level sensor 13 may be positioned at or near the top of the vaporization chamber 1 to prevent over-fdling. [0023] Optionally, an ignitor 14 may be provided adjacent to the burner 3 to light the flame.

Any burner ignition system may be provided, such as an electric spark ignitor or piezo ignitor. Alternatively, the burner 3 may be lit manually, using a match, hand-held lighter, or other ignition source. [0024] The present invention has been described and illustrated with reference to an exemplary embodiment, however, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as set out in the following claims. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed herein.