VAPOR FLAME BURNER AND METHOD OF OPERATING SAME

Abstract

Apparatus and method for creating a vapor flame in a burner having an adjustable BTU output using a liquid diesel fuel and air mixture. A burner tube within which the fuel air mixture initially combusts to form a flame is heated from its outside circumference by a combustion flame within a counterflow chamber surrounding the burner tube. The temperature of the burner tube is maintained at a value where the fuel air mixture within the burner tube turns into vapor with a lack of combustion air which vapor fuels the flame within the counterflow chamber and which vapor also travels to a burner head where it combusts. The combustion air and compressor air are varied following establishment of the vapor flame to increase and decrease the heat output from the burner.

Description

INTRODUCTION

This invention relates to an improved burner and, more particularly, to an improved diesel fueled burner which produces a vapor flame with an adjustable BTU output.

BACKGROUND OF THE INVENTION

The use of diesel burners and heaters is, of course, pervasive in industry. Diesel burners may be powered where the use of electricity is required to operate the burner and non-powered where the diesel fuel is manually ignited to create a flame which is then self-sustaining until the fuel supply terminates.

If the diesel burner is powered, auxiliary components such as fuel pumps, compressors, combustion fans and the like combine in operation to produce a fuel/air mixture leaving a nozzle where combustion subsequently occurs, the ignition of the flame generally being initiated by an igniter. Diesel fuel has a healthy caloric content which results in relatively excellent BTU output when the diesel fuel is ignited under satisfactory combustion conditions.

In one form of such powered heaters, electrically powered pumps may be used to pump a coolant into an area adjacent the burner. The coolant is heated by the burner and the coolant, in turn, may be used to heat potable water through a heat exchanger where the potable water is then used for shower or cooking purposes. Alternatively, the heated coolant is routed through space heaters where the heat from the coolant emanates into living quarters for comfort. In yet a further embodiment, the coolant itself may be potable water which is used for showers and the like. And, further, the coolant may be used to heat a second coolant by way of a heat exchanger.

Such diesel burners are known. In one such diesel burner, manufactured by International Thermal Research Ltd., the owner of the present invention, and known as the HURRICANE (Trademark) heater, a burner uses an air aspirated nozzle which draws diesel fuel into the nozzle when air is added to the nozzle by way of a compressor. The air and fuel mixture emanate from the nozzle and combust, initially by way of a igniter and, thereafter, by the heat of the continued combustion to form a combustion flame within a burner tube. The combustion flame creates the heat required for heating the coolant or potable water surrounding the burner tube within a coolant jacket or other coolant container.

Another heater designed by International Thermal Research Ltd. is a heater used for military purposes, primarily within field kitchens. This powered diesel fueled heater is known as the MBU (Modern Burner Unit) heater. A large number of such heaters of this type have been sold and used throughout the world. The MBU heater does not heat a coolant. Rather, the heat from the combustion flame is used to provide heat for ovens, griddles and the like generally used in field kitchens.

As noted, the MBU and HURRICANE heaters both use an air aspirated nozzle to draw fuel into the nozzle. The combustion of the fuel-air mixture occurs in a burner tube. A low pressure airstream ensures efficient combustion within the burner tube. These heaters have operated in a satisfactory manner but there are certain improvements that can be usefully made.

One disadvantage of existing burners heretofore described is that the fuel-air combustion process within the burner tube creates noise due in part to turbulence within the air-fuel mixture. While proper heater location and/or sound proofing may substantially reduce the noise apparent to users, the noise may still be distracting particularly when sleeping or relaxing in quiet conditions and when the heater is located nearby. A second disadvantage of the prior art burners is that the burner tube required to support the combustion is necessarily of a relatively large diameter to ensure efficient and adequate combustion. This increases the size of the burner where a smaller footprint may be desirable due to limited space being available for the heater. A third disadvantage of the prior art is that combustion by-products of carbon monoxide and soot are always present to a larger or smaller degree in a diesel fueled burner. The combustion envelope is dependent on external factors such as temperature and altitude which may change the percentage of combustion by-products during combustion and adversely affect the efficiency of the heater under certain conditions.

Yet a further disadvantage is that the prior art burners cannot be fully enclosed because the only combustion air available is ambient air. The lack of the ability to enclose the burner results in significant heat loss which adversely affects operating efficiency.

A vapor burner is described in some detail in U.S. Pat. No. 3,620,657 (Re. 28,679) to Robinson, the contents of which are incorporated by reference. The Re. '679 patent teaches the use of ambient air for combustion and a constant BTU heat output. There are advantages in increasing operating flexibility and efficiencies of the burner in accordance with present invention.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is disclosed a liquid fueled burner comprising a burner head, a burner tube, a nozzle for ejecting fuel into said burner tube, a counterflow chamber surrounding a substantial portion of said burner tube, first and second sets of perforations extending through said burner tube into said counterflow chamber, said second set of perforations being located adjacent said nozzle and said first set of perforations being located distant of said nozzle, an adjustable combustion fan to provide combustion air to said burner tube and said counterflow chamber, said burner head being operably connected to said burner tube and means to increase and decrease the supply of said fuel and to increase and decrease said combustion air.

According to a further aspect of the invention, there is disclosed a burner utilising a liquid fuel supply fuel line to supply liquid fuel to a nozzle, a variable speed compressor to introduce air under pressure to said nozzle and to draw said liquid fuel into said nozzle to produce an air-fuel mixture emanating from said nozzle into a burner tube, an adjustable combustion fan to supply combustion air to said burner tube, an igniter to ignite the air-fuel mixture emanating from said nozzle and to commence combustion of said air-fuel mixture within said burner tube, a burner head, a counterflow chamber surrounding said burner tube, a first set of perforations extending though said burner tube located at the distant end of said burner tube, said first set of perforations allowing the escape of at least a portion of said fuel vapor in said burner tube into said counterflow chamber, adding combustion air to said counterflow chamber to form a flame within said counterflow chamber, a second set of perforations extending through said burner tube located adjacent said nozzle, said second set of holes allowing the entry of fuel vapor from said counterflow chamber into said burner tube and controls to increase or decrease the supply of air to said nozzle and to said burner head.

According to yet a further aspect of the invention, there is disclosed a method of creating a combustible vapor from a liquid fuel within a burner comprising the steps of introducing a liquid air-fuel mixture into a burner tube from a nozzle, supplying combustion air to said burner tube, passing at least a portion of said air-liquid fuel mixture from said nozzle through an igniter to ignite said air-liquid fuel mixture into a flame within said burner tube, allowing said combustion flame to emanate from a burner head located downstream of said burner tube, allowing fuel vapor within said burner tube to escape to a counterflow chamber surrounding said burner tube via a first set of perforations in said burner tube located distant from said nozzle, supplying combustion air to said counterflow chamber to combust said fuel vapor within said counterflow chamber, heating at least a portion of the outside of said burner tube with said flame in said counterflow chamber, restricting the flame within said counterflow chamber by a flame suppressor and allowing byproducts of said combustion of said flame in said counterflow chamber to be reintroduced to said burner tube through a second set of perforations located in said burner tube at the end of said burner tube adjacent said nozzle, terminating the operation of said igniter after a predetermined time period wherein the temperature within said burner tube is high enough to maintain vaporization of said air-diesel fuel mixture emanating from said nozzle and allowing said flame within said burner tube to extinguish, said flame appearing on said burner head and inside said counterflow chamber.

According to still yet a further aspect of the invention, there is disclosed a counterflow chamber comprising a counterflow air chamber surrounding a burner tube, a first set of perforations extending from said burner tube into said counterflow chamber to allow passage of fuel vapor from said burner tube, a second set of perforations extending from said counterflow chamber into said burner tube to allow combustion by products into said burner tube and an inlet for combustion air to enter said counterflow chamber and combust said fuel vapor within said counterflow chamber thereby to heat the circumference of said burner tube.

According to still yet a further aspect of the invention, there is disclosed a burner head for a burner comprising an outer flame surface with perforations extending through said flame surface from the outside of said flame surface to the inside of said flame surface, an inner baffle located within said burner head, said inner baffle having perforations extending through said baffle, said first outer flame surface and said inner baffle being concentric, a first flame sensor outside said burner head adjacent said flame surface and a second flame sensor located within said burner head.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way of example only, with the use of drawings in which:

FIG. 1 is a diagrammatic plan view of the burner within its frame according to the invention and which particularly illustrates the components used in support of combustion within the burner;

FIGS. 2A and 2B are diagrammatic, isometric and partial cutaway views, respectively, illustrating the assembled burner according to the invention and in which FIG. 2B particularly illustrates the path of burner head and counterflow chamber air supply air through the burner;

FIG. 2C is a diagrammatic side and partial sectional view of the burner according to the invention particularly illustrating the assembled igniter and nozzle assembly and the counterflow chamber;

FIGS. 3A, 3B and 3C are diagrammatic side and partial sectional views similar to FIG. 2C, particularly illustrating the burner phases during the transition from the combusted air-fuel flame phase to the vapor combustion phase;

FIG. 4 is a diagrammatic front view of the front panel member used with the burner of FIGS. 1-3;

FIGS. 5A and 5B are diagrammatic views of the front and back face plates of the burner according to the invention which facilitate the various air flow streams; and

FIG. 6 is a diagrammatic isometric and partial cutaway view of the burner head specifically illustrating the outer and inner flame rods and further illustrating the inner baffle positioned within the burner head.

DESCRIPTION OF SPECIFIC EMBODIMENT

It will be appreciated that there are some aspects of burner operation and fuel vapor formation within the burner according to the invention that are not wholly understood at the present time. Nevertheless, the explanations given hereafter are being described as they are understood by the applicants for the purpose of full disclosure of the invention as it now appears.

Referring now to the drawings, a burner according to the invention is illustrated generally at 100 in FIG. 1. The burner 100 is particularly useful in military field kitchens and the like which are used for food preparation for troops and/or support personnel in the field. The burner 100 is typically intended to be inserted within an oven or under a griddle or a food preparation container. It may also be used as part of another appliance. The heat generated by the burner 100 heats the oven, griddle, container or appliance.

The burner 100 has a number of components required for supporting combustion. A compressor 101, preferably being a variable speed compressor in order to provide more or less air to the nozzle 102, provides air to the burner nozzle 102 (FIG. 2C) and a fuel pump 103 provides fuel to a fuel regulator 104 which is connected to a solenoid 118 which is connected to the fuel block 115 (FIGS. 1 and 2C) which is connected to the nozzle 102. The solenoid 118 is used to stop fuel flow after burner operation is terminated to prevent fuel droplets from leaving the nozzle 102 and from accumulating on the bottom of the heater casing 123 and further to prevent fuel being siphoned back form the nozzle 102 which allows a quick and clean start of the fuel from nozzle 102. The fuel pump 103 is connected through a fuel filter 119 directly to the fuel inlet 110 of the burner 100 which allows the entry of fuel from a fuel storage device such as a tank or jerry can (not illustrated). A combustion fan 111, preferably being a variable speed combustion fan to provide more or less air to the burner 100, provides combustion air to the burner tube 112 (FIG. 2C) by way of holes 113 in the nozzle tube 114. Combustion fan 111 also provides combustion air to the burner head 140 and to the counterflow chamber 150 through holes 161, 162 (FIGS. 2A and 5A), respectively, as will be described.

A control board 120 (FIG. 1) provides control for the different phases of the burner 100 as will be described. A 24V DC power supply is used with the burner 100 and the power cables are connected to the power connector 121. A cooling fan 122 is provided within the burner 100 to cool the components from the heat generated by combustion. The cooling fan 122 takes cool air into the heater casing 123 of the burner 100 through inlet louvers 130 (FIG. 4) and expels the heated air through exit louvers 135 on the front panel generally illustrated at 124 in FIG. 4 of the heater casing 123. The cooling fan 122 also cools the electrical and mechanical components, just described, following burner shutdown as will be described.

A carrying handle 131 (FIG. 4) is used for inserting and removing the burner 100 from the appliance (not illustrated) in which the burner 100 is to be used. An ON-OFF switch 132 provides for activation of the burner 100 and a rotary dial potentiometer 133 allows for increasing and decreasing the heat output from the burner 100 as will be described. An indicator light 134 provides an indication of the phase of the flame emanating from the burner head 140 (FIG. 2C) and the status of the burner 100 as will further be described.

Referring now to the inside of burner 100 and with particular reference to FIGS. 2A, 2B and 2C, the burner head 140 is connected to the burner tube 112 by curved tubing 142 (FIG. 2C), conveniently being the same diameter as the burner tube 112. The burner tube 112 has a first plurality of holes 143 located about the circumference of the burner tube 112 at the end of the burner tube 112 distant from the nozzle 102. Likewise, a second plurality of holes 144 is located about the circumference of the burner tube 112 at the end of the burner tube 112 located closer to the nozzle 102.

The counterflow chamber 150 (best seen in FIG. 2C) is located around the circumference of the burner tube 112 and extends a distance somewhat greater than the distance between the first and second plurality of holes 143, 144. The counter flow chamber 150 is joined to the front plate 160 by welding. The counterflow chamber 150 is preferably a sealed chamber defined at its distance end by counterflow chamber intake member 151 such that the combustion air traveling through holes 161 (FIG. 2B) to the burner head 140 does not adversely affect the operation of the combustion within the counterflow chamber 150. However, by allowing a certain amount of external air to enter the counterflow chamber 150, combustion within the counterflow chamber 150 may be adjusted which can be desirable under certain operating conditions.

An air chamber 105 (FIGS. 2A and 2B) is in the form of an enclosure defined by front plate 160, an end plate 116, two side walls 106, 107, a bottom plate 108 (FIG. 3C) and a top plate 109. The air chamber 105 surrounds the counterflow chamber 150 and accepts the air entering the burner 100 through the counterflow air intake holes 162 (FIGS. 2A and 2B) and securely conveys this air to the entrance holes 145 (FIGS. 2B and 2C) of the counterflow chamber air intake member 151 as indicated by the arrows 156 in FIG. 2B.

The counterflow chamber air intake member 151 (FIG. 2C) is mounted around the burner tube 112 and forms the end of counterflow chamber 150. A counterflow ring 163 (FIGS. 2C and 3C) extends around and is concentric with the burner tube 112. It is positioned over the first plurality of holes 143 as seen in FIGS. 3A, 3B and 3C. The ring 163 is used to keep the counterflow flame from extinguishing when the extent of the flame is changed by way of air output from the compressor 101 and/or the combustion fan 111.

The entrance holes 145 in air intake member 151 are positioned around the circumference of the counterflow ring 163 (FIG. 2B).

A flame suppressor 164 (FIG. 2C) is provided around burner tube 112 to prevent the flame in counterflow chamber 150 from reaching the second plurality of holes 144 and re-entering the burner tube 112 which could otherwise cause re-ignition in the burner tube 112.

The front plate 160 (FIGS. 2B and 5A) has a series of holes 161, 162 extending therethrough for inletting combustion air. Holes 162 admit air to be circulated through the counterflow chamber 150 (FIG. 2C). Holes 161 admit air used for combustion by the flame on the burner head 140. The flow of air is best illustrated diagrammatically in FIG. 2B with the air flow for the counterflow chamber 150 being indicated by numeral 156 and the air for the burner head 140 being indicated by numeral 170.

The nozzle tube 114 (FIG. 2C) is operable to hold the igniter tube 152. An igniter 141 is mounted within the igniter tube 152 and is positioned within the nozzle tube 114 such that it extends to the outer portion of the air-fuel mixture emanating from the nozzle 102. The timing of the igniter 141 is controlled by the control board 120 (FIG. 1) as will be described.

Operation

In operation, the ON-OFF switch 132 (FIG. 4) will be set to ON by the user. This initiates the operation of the combustion fan 111 (FIG. 1), the fuel pump 103 and the igniter 141 within the igniter tube 152 (FIG. 2C). It also initiates operation of the warmup LED 134 (FIG. 4) to indicate the status of the burner 100 during the startup transitions. A ten (10) second delay is built into the startup sequence to allow the igniter 141 to reach operating temperature. After the ten (10) second delay, the combustion fan 111 shuts down for three (3) seconds to terminate air flow over the igniter 141 and to thereby allow the igniter 141 to reach an increased temperature prior to fuel ignition.

The combustion fan 111 (FIG. 1) provides combustion air to the nozzle tube 114 (FIG. 2C) through holes 113 which then passes to the burner tube 112 to support combustion of the fuel (FIGS. 2B and 2C) within the burner tube 112. The combustion fan 111 also provides air through the holes 161, 162 (FIG. 2B) to supply combustion air to the burner head 140 and to the entrance holes 145 in the air intake member 151 for the counterflow chamber 150. After the three (3) second delay, the combustion fan 111, the compressor 101 and the fuel pump 103 are activated. The control board 120 is programmed to set the output of compressor 101 and the output voltage of combustion fan 111 to the appropriate values during the startup phase to better control any smoke which may be produced during startup. Such programming is done depending on the operating altitudes and operating temperatures where the burner 100 is located.

With reference now to FIGS. 2C and 3A and under the influence of the compressor 101, the nozzle 102 sprays a fine mist of fuel and air into the burner tube 112 which will combust with the added combustion air and form a burner tube flame 153 within the burner tube 112. Flame 153 will travel through the burner tube 112 and emanate from the burner head 140, supported by the combustion air 170 directed to the burner head 140 (FIG. 2B) by combustion fan 111 and by ambient air. The force of the fuel spray from the nozzle 102 will form a small suction at the inlet of the burner tube 112 thereby setting up a slightly negative pressure within counterflow chamber 150 via holes 144. Vapor from the burner tube 112 will leave the burner tube 112 via first plurality of holes 143 and when the vapor contacts the combustion air provided by combustion fan 111 entering the counterflow chamber 150 through holes 145 (FIG. 2C), it will combust within the counterflow chamber 150 and form a flame shown diagrammatically at 154 in FIG. 3B. The flame 154 is deflected and guided by the counterflow chamber ring 163 so that it heats the burner tube 112 which needs to be hot enough to allow the formation of the required vapors from the fuel-air mixture passing through the burner tube 112 during the vapor flame phase. The ring 163 will also prevent the counterflow chamber flame 154 from being extinguished by the flow of combustion air from the combustion fan 111 in the counterflow chamber 150 and the flow of the air/fuel vapor mixture coming out of holes 143 due to the pressure generated in the burner tube 112 by the compressor 101 and combustion fan 111.

Referring to FIG. 3C, the burner 100 is shown in its normal operating mode with the counterflow chamber flame 154 maintaining the burner tube 112 at an elevated temperature sufficient to create vapor from the fuel-air mixture entering the burner tube 112. Once this fuel-air mixture turns into vapor after extinguishing the flame 153 in the burner tube 112, a portion of the vapor enters the counterflow chamber 150 through the holes 143 as described. The vapors within the burner tube 112 will also flow to the burner head 140 where they form a flame 155 on the burner head 140 with the addition of the combustion air.

The combustion air 156 needs to be of a volume to allow clean burning of the vapor in the counterflow chamber 150 which keeps the burner tube 112 hot enough to create vapors to burned on the burner head 140.

The flame suppressor 164 (FIGS. 2C and 3B) prevents the flame 154 from the vapor combustion within the counterflow chamber 150 from reentering the burner tube 112 through the second plurality of holes 144 extending through the burner tube 112 adjacent the nozzle 102 (FIG. 2C) and reigniting a flame 153 in the burner tube 112.

To ensure proper establishment of the vapor flame phase illustrated in FIG. 3C, the compressor 101 and combustion fan 111 are set to operate at predetermined values by the control board 120 (FIG. 1). These settings are obtained usually by manual trial and error according to the location of the burner 100 and the altitude at which it is operating. The igniter 141 will remain on for a period of approximately thirty (30) seconds and when power to the igniter 141 is terminated and the outputs of compressor 101 and combustion fan 111 are adjusted, the flame 153 within the burner tube 112 is extinguished by the gases from the counterflow chamber 150 entering the burner tube 112 and also by reducing the quantity of combustion air from combustion fan 111 and changing the air/fuel ratio. The burner tube 112 is at a temperature where the atomized air-fuel mixture emanating from the nozzle 102 is converted to vapor or gas by the elevated temperature of the burner tube 112 which is maintained by the combustion of the vapor and the creation of the flame 154 within the counterflow chamber 150 (FIG. 3B). With the establishment of a satisfactory flame 154 within the counterflow chamber 150 (FIG. 3C), the non-combusted vapors created by the heating of the burner tube 112 with the flame 154 in the counterflow chamber 150 will proceed to the burner head 140 where they will combust into flame 155 on the burner head 140 by the increased air supplied by the ambient surroundings and also by the adjustment of the combustion air provided by the combustion fan 111. The indicator light 134 will stop flashing under the direction of control board 120 when the normal operating mode of the burner 100 is reached as illustrated in FIG. 3C and will assume a solid color to indicate that the normal operating mode of the burner 100 has been reached.

After the normal operating mode of FIG. 3C is reached, the air supplied from the compressor 101 and the combustion fan 111 may be adjusted by way of the rotary dial potentiometer 133 (FIG. 4). This adjustment allows the air-fuel flow and combustion air to increase or decrease and thereby allows the BTU heat output of the burner 100 to be varied as may be desired by the user.

Following the desired operation duration of the burner 100, the ON-OFF switch 132 is turned off to terminate operation of the burner 100. The operation of the igniter 141, the air compressor 101, the fuel pump 103 and the indicator light 134 terminate. A two (2) minute purge period requires the cooling fan 122 and the combustion fan 111 to remain on to dissipate fuel vapors within the burner 100 and to cool the components. The cooling fan 122 and the combustion fan 111 further remain on for a cool down period, conveniently being about twenty (20) minutes, to dissipate any vapors remaining in the burner 100 after shutdown and to more quickly allow the burner 100 and the various electronic and mechanical components to cool. Following the cool down period, the cooling fan 122 and the combustion fan 111 will also shut down. The burner 100 is then quiescent until further operation of the burner 100 is desired by the user.

It will be appreciated that the timing sequences described above in association with the start up and shut down of the burner 100 may readily be modified and that the sequences lend themselves to automation through changes to the control board 100. Likewise, the voltages applied to the various fans and compressors may be increased or decreased to vary the performance of those components, likewise through changes made to the control board.

To prevent any potential “flash back” on the burner head 140, a flame sensor 181 may be conveniently positioned within the burner head 140 as seen in FIG. 6. This sensor 181 will immediately terminate operation of the burner 100 if a flash back flame is detected within the burner head 140. In a further embodiment, if the sensor 181 senses a flame within the burner head 140, it can quickly initiate a sequence to again start the vapor flame on the burner head 140 without the necessity of restarting the start up sequence. In such an embodiment, time is saved for the restoration of the vapor flame.

Although the burner head 140 has been found to operate in a satisfactory manner with no inner baffle added to the burner head 140, it has been found that the addition of an inner and concentric baffle 171 (FIG. 6) is beneficial. The concentric baffle 171 preferably has perforations 172 extending from its inside diameter to its outside diameter. The use of the baffle 171 has been found to increase mixing of the fuel vapor emanating from the burner 100 into the burner head 140 and the combustion air. CO has therefore been found to be reduced substantially.

A further flame rod 173 is positioned outside the burner head 140 as also seen in FIG. 6. The use of a flame rod 173 allows the burner 100 to sense the presence of the flame 155 (FIG. 3C) on the burner head 140. In operation, the flame rod 173 will be positioned where the initial combustion flame from the burner head finally completely surrounds the burner head 140 after startup. Thus, when the flame rod 173 senses the flame on the burner head 140 after start up of the burner 100, it will instruct the control board 120 to immediately proceed with the vapor flame phase of operation thereby also saving significant time during startup. In the event no flame is sensed by the flame rod 173, operation of the burner will terminate under the operation of control boar 120. This is a safety precaution.

To allow a complete sealing of the burner 100 within an appliance in which it is used, a sealant member (not illustrated) may conveniently be positioned on the top of the case 123. The burner 100 may then be firmly sealed within the appliance (not shown) by bringing the sealing member into contact with the appliance to prevent the egress of heated air and to prevent the ingress of ambient air to the burner 100.

Many further modifications will readily occur to those skilled in the art to which the invention relates and the particular embodiments described herein should be taken as illustrative of the invention only and not as limiting its scope as defined in accordance with the accompanying claims.

Claims

1. A liquid fueled burner comprising a burner head, a burner tube, a nozzle for ejecting fuel into said burner tube, a counterflow chamber surrounding a substantial portion of said burner tube, first and second sets of perforations extending through said burner tube into said counterflow chamber, said second set of perforations being located adjacent said nozzle and said first set of perforations being located distant of said nozzle, an adjustable combustion fan to provide combustion air to said burner tube and said counterflow chamber, said burner head being operably connected to said burner tube and means to increase and decrease the supply of said fuel and to increase and decrease said combustion air.

2. A burner utilising a liquid fuel supply fuel line to supply liquid fuel to a nozzle, a variable speed compressor to introduce air under pressure to said nozzle and to draw said liquid fuel into said nozzle to produce an air-fuel mixture emanating from said nozzle into a burner tube, an adjustable combustion fan to supply combustion air to said burner tube, an igniter to ignite the air-fuel mixture emanating from said nozzle and to commence combustion of said air-fuel mixture within said burner tube, a burner head, a counterflow chamber surrounding said burner tube, a first set of perforations extending though said burner tube located at the distant end of said burner tube, said first set of perforations allowing the escape of at least a portion of said fuel vapor in said burner tube into said counterflow chamber, adding combustion air to said counterflow chamber to form a flame within said counterflow chamber, a second set of perforations extending through said burner tube located adjacent said nozzle, said second set of holes allowing the entry of fuel vapor from said counterflow chamber into said burner tube and controls to increase or decrease the supply of air to said nozzle and to said burner head.

3. A burner as in claim 2 and further comprising a ring member being concentric to said burner tube and surrounding at least a portion of said burner tube, said ring member being positioned generally over said first set of perforations in said burner tube.

4. A burner as in claim 3 and further comprising a flame suppressor surrounding said burner tube and being situated within said counterflow chamber between said first and second sets of perforations in said burner tube.

5. A burner as in claim 4 and further comprising a sealing member between said burner to seal said burner in an appliance within which said burner is positioned to prevent the ingress and egress of air to and from said burner.

6. A burner as in claim 5 and further comprising a first flame sensor outside said burner head to sense the presence or absence of a flame on said burner head.

7. A burner as in claim 6 wherein said burner head has a first outer flame surface with perforations extending through said flame surface from said outside of said flame surface to the inside of said flame surface and further comprising an inner baffle located within said burner head.

8. A burner as in claim 7 wherein said inner baffle has perforations extending through said baffle.

9. A burner as in claim 8 wherein said first burner head and said first flame surface are round and wherein said inner baffle is concentric to said flame surface.

10. A burner as in claim 9 and further comprising a second flame sensor positioned within said burner head to sense the presence of a flame within said burner head.

11. A method of creating a combustible vapor from a liquid fuel within a burner comprising the steps of introducing a liquid air-fuel mixture into a burner tube from a nozzle, supplying combustion air to said burner tube, passing at least a portion of said air-liquid fuel mixture from said nozzle through an igniter to ignite said air-liquid fuel mixture into a flame within said burner tube, allowing said combustion flame to emanate from a burner head located downstream of said burner tube, allowing fuel vapor within said burner tube to escape to a counterflow chamber surrounding said burner tube via a first set of perforations in said burner tube located distant from said nozzle, supplying combustion air to said counterflow chamber to combust said fuel vapor within said counterflow chamber, heating at least a portion of the outside of said burner tube with said flame in said counterflow chamber, restricting the flame within said counterflow chamber by a flame suppressor and allowing byproducts of said combustion of said flame in said counterflow chamber to be reintroduced to said burner tube through a second set of perforations located in said burner tube at the end of said burner tube adjacent said nozzle, terminating the operation of said igniter after a predetermined time period wherein the temperature within said burner tube is high enough to maintain vaporization of said air-diesel fuel mixture emanating from said nozzle and allowing said flame within said burner tube to extinguish, said flame appearing on said burner head and inside said counterflow chamber.

12. A method as in claim 11 and further comprising locating a ring member over said first set of holes around said burner tube and within said counterflow chamber.

13. A method as in claim 12 and further comprising positioning a flame grid between said first and second set of holes within said counterflow chamber and around said burner tube.

14. A counterflow chamber comprising a counterflow air chamber surrounding a burner tube, a first set of perforations extending from said burner tube into said counterflow chamber to allow passage of fuel vapor from said burner tube, a second set of perforations extending from said counterflow chamber into said burner tube to allow combustion by products into said burner tube and an inlet for combustion air to enter said counterflow chamber and combust said fuel vapor within said counterflow chamber thereby to heat the circumference of said burner tube.

15. A burner head for a burner comprising an outer flame surface with perforations extending through said flame surface from the outside of said flame surface to the inside of said flame surface, an inner baffle located within said burner head, said inner baffle having perforations extending through said baffle, said first outer flame surface and said inner baffle being concentric, a first flame sensor outside said burner head adjacent said flame surface and a second flame sensor located within said burner head.