US3032096A - Combustion apparatus - Google Patents

Description

May 1, 1962 M. w. sTouT coMBUsTIoN APPARATUS Filed May l, 1955 .HS INS..

United States Patent G r 3,032,096 COMBUSTION APPARATUS Minor W. Stout, 550 Ridge Ave., Webster Groves, Mo. Filed May 1, 1953, Ser. No. 352,493 6 Claims. (Cl. 158-11) This invention relates to improvements in combustion apparatus. More particularly this invention relates to improvements in combustion apparatus of high efficiency.

It is therefore an object of the present invention to provide an improved combustion apparatus of high efficiency.

Many forms of combustion apparatus utilize burners that project a fuel into a large lire-box and depend upon aspirated air to provide the oxygen necessary to convert the fuel into carbon dioxide. This aspirated air is drawn into the fire-box by the action of a chimney connected to the outlet of the lire-box. In such apparatus there is usually a central zone of raw fuel, a secondary zone where the fuel has been converted to aldehydes, alcohols, and carbon monoxide, and a third zone where the aldehydes and alcohols and carbon monoxide are converted to carbon dioxide. If the fire-box is large enough, and if the aspiration of the secondary air occurs at a sufficiently high rate, the fuel from the burners may be converted to carbon dioxide to a great extent. However, if the aspiration of the air varies somewhat, as it will inevitably do with changes in temperature and pressure, the aldehydes, alcohols and carbon monoxide may not be completely converted to carbon dioxide. Even where the aldehydes and alcohols and carbon monoxide are converted to carbon dioxide in such combustion apparatus, an excess of aspirated air is needed to insure full combustion, and that excess of inspirated air wastes heat. This is so because part of the heat from the combustion products must be diverted into the excess air which becomes a part of the products of combustion and passes out through the chimney with those products of combustion. In addition, such apparatus is unduly costly because of the large size of the tire-box required. For these various reasons, prior combustion apparatus which utilized a large fire-box and aspirated air to burn fuel have been found objectionable. The present invention obviates these objections by providing combustion apparatus which provides predetermined quantities of air and fuel and confines those quantities in close quarters while thoroughly intermingling those quantities. Instead of depending upon a thermosiphon effect to move unburned fuel and partially burned fuel into contact with oxygen in the air, the present invention positively and vigorously intermixes the air and fuel together in the combustion area. As a result, the cornbustion proceeds swiftly and in a small space and full burning of the fuel is attained with very little excess air. In addition, the variations in combustion efficiency due to stack or chimney action are eliminated because the cornbustion apparatus is provided with blowers that always provide the required quantities of air. It is therefore an object of the present invention to provide combustion apparatus which introduces air and fuel under pressure into a conned ccmbustion zone and thoroughly inter-mixes the air and fuel to obtain complete combustion with a minimum of excess air.

The combustion apparatus provided by the present invention attains complete and thorough mixing of the air and fuel by pre-mixing a part of the fuel with air prior to its introduction into the combustion zone. When this mixture of fuel and air is introduced into the combustion zone and is ignited, it is immediately subjected to cross currents of secondary air which will break through and destroy the traditional blue raw fuel cone and the almost invisible secondary cone experienced with pre-mixed fuel. Such an arrangement provides a homogeneous flame wherein the secondary air intimately contacts and mixes 3,032,096 Patented May 1, 1962 ICC with the pre-mixed air and fuel. As a result, a homogeneous ame of rapidly burning character is established and a continuing turbulence is obtained which keeps the secondary air and the pre-mixed fuel and air constantly moving relative to each other. In this turbulent flame the fuel is almost immediately converted to the aldehydes and alcohols and carbon monoxide and then almost immediately thereafter converted to carbon dioxide; and there are no perceptible zones of combustion stages. As a result, the fuel is quickly and completely converted to carbon dioxide with full evolution of heat, and there is no opportunity for any of the fuel to escape to the chimney or stack in the form of carbon monoxide, aldehydes or alcohols and thus be lost. With this construction it is possible to reduce the percent of excess air from the usual range of 50% to 200% excess air to less than 10% excess air. This is a great economy of heat because the excess air merely absorbs heat that would otherwise go into the water or other material to be heated by the products of combustion, and the excess air carries that heat out of the stack or chimney.

The combustion apparatus provided by the present invention divides the fuel into two sections and utilizes one section to establish a low iire and uses the other section to establish a high fire in the combustion area or zone. Each of the sections of fuel is in turn premixed with air to assure speedy combustion when the fuel reaches the combustion area or zone, and each `section of the fuel is provided with its own secondary air. This arrangement is very desirable because it enables the combustion apparatus to closely approximate the optimum air-fuel ratio under different load conditions. This .is not possible where the flow of fuel is modulated in accordance with changes in the load. The section of fuel which supports the low fire can be regulated in conjunction with its primary and secondary air to provide optimum burning conditions and similarly the other section of the fuel which provides the high fire operation can be adjusted in connection with its primary and secondary air to provide optimum burning conditions. Where this is done, optimum burning conditions will be experienced whether the low re is operating by itself or is operating in conjunction with the high fire; and this optimum burning is attained throughout the range of anticipated loads on the combustion apparatus. It is therefore an object of the present invention to provide combustion apparatus wherein a part of the fuel is used to support a low fire and wherein the rest of the fuel is used to support a high lire and wherein each section of the fuel has its own primary and secondary air.

The combustion apparatus provided by the present invention can utilize two different types of fuel. For example, it can utilize gaseous fuels and non-gaseous but fluid fuels. Even where the combustion apparatus provided by the present invention utilizes two different fuels, it still assures full combustion of both of those fuels, It does this by placing the nozzle for the less readily ignited fuel at the center of the combustion apparatus and surrounding that nozzle with the nozzle for the more readily ignited fuel. With such a construction the less readily ignited fuel is enshrouded and encased within the flame and cornbustion products of the more readily ignited fuel and it is quickly raised to the ignition point. In addition, each fuel is provided with its own source of secondary air and thus it can be assured of a full supply of oxygen. Moreover, the fuels and the air for supporting the burning of those fuels are caused to rotate in opposite directions and to thoroughly intermingle and mix with each other to promote full and rapid combustion to carbon dioxide. With this construction the less readily ignited fuel quickly rises to burning temperature as it passes down the length of the surrounding and enshrouding flame and is itself caused to burn. The encircling and enshrouding flame is moving transversely of the combustion area and the less readily ignited fuel is also moving transversely of that combustion area and in a very short distance the fuels and the supporting air will be thoroughly intermingied and will promptly convert all of the fuel to carbon dioxide. It is therefore an object of the present invention to provide combustion apparatus wherein less readily ignited fuels are directed down the center of the combustion area and wherein readily ignited fuel is used to enshroud and encircle the less readily ignitible fuel.

Prior combustion apparatus has utilized an electric spark to ignite the fuel when the combustion apparatus initiated a burning cycle. Customarily this electric spark would ignite the fuel as desired and the combustion apparatus would operate effectively. However, in scme instances, the fuel would leak during off periods and would develop an explosive mixture adjacent the electrodes when an on cycle was to start. This is especially true where the fuel is gas, and in a number of instances explosions have occurred which are known to have caused personal as well as property damage. This leakage can happen even if the valves are in perfect condition because pipe scale and other foreign matter from the fuel line can lodge between the valve element and the valve seat and prevent full closing. The present invention obviates any danger of explosions in combustion apparatus by providing a continuous pilot which will ignite and harmlessly burn any fuel leaking from the fuel nozzles during ott cycles. In addition, that continuous pilot will provide immediate ignition of the fuel when the on cycle begins and there will be no opportunity for the accumulation of dangerous gases in the combustion area. It is therefore an `object of the present invention to provide combustion apparatus equipped with a continuously burning pilot.

In large urban areas it is often customary to supply gas on an interruptible basis, so that when the weather becomes quite cold and the supply of gas is low, the use of gas in industrial plants can be interrupted. Where this arrangement is used, it is necessary for the industrial plants to have standby burners available to supply the needed heat for operation. In some cases it is the practice to mount the gas burner in the Wall of the rebox and to bodily remove that gas burner and substitute therefor an oil burner or a stoker during periods of interruption. This arrangement is costly and is inconvenient since it cannot be done automatically. Instead, workmen break away part Vof the Wall containing the gas burner and remove that gas burner, insert the oil burner or stoker in position and then cement up the Wall around that burner or Stoker. After the cold weather has passed, the oil burner or Stoker must be bodily removed from the wall and the gas burner replaced. This obviously is very objectionable. The present invention obviates this objection by providing combustion apparatus which contains both the Vprimary heat source and the alternative heat source, and it positions those heat sources so close together that the conversion from one to the other can be obtained without perceptible interruption in the heating of the firebox. Specifically, the combustion apparatus provided by the present invention has a nozzle for the alternative fuel directed into the combustion zone and has a nozzle for the regularly used fuel directed into the same combustion zone from the same position in the frebox. When the alternative fuel is to be used it will be ignited by the regularly used fuel and then the regularly used fuel will cut off during the period of cold Weather. At the conclusion of the cold weather the alternative fuel will be cut off and the regularly used fuel restored; and all of this Will occur Without any need of shifting the position of the burners.

The separation of the fuel which is regularly used into two sections, one to support a low fire and one to support a high tire, is ideal where an alternative fuel is to Vbe used during the cold weather; because the low lire can help vto burn and thoroughly consume the 'alternative fuel.

Where the alternative fuel is oil or powdered coal, that fuel will be directed into the low tire flame and will be quickly raised to igniting temperature and will be so intimately admixed with the low tire and with the secondary air for the alternative fuel that complete combustion will be assured.

The combustion apparatus of the present invention provides full cooling of the alternatively used burners where the regularly used fuel is on an interruptible basis. Specifically, where oil or powdered coal is to be burned ou an alternative fuel basis, the nozzle for the oil or powdered coal is surrounded by an air nozzle which will keep that fuel nozzle cool and which will drive the products of combustion away from that nozzle. Similarly, another air nozzle will be placed adjacent the nozzle for the regularly used fuel and will cool that nozzle and will drive the products of combustion away from that nozzle. In this way, the alternatively used burners can be fully protected against overheating. This not only prolongs the life of the combustion apparatus but also insures that such apparatus will be instantly ready to perform its function whenever it is required to do so.

The combustion apparatus provided by the present invention utilizes eccentrically disposed passageways to conduct air and fuel to the nozzles therefor and thus obtains a rotating action of the fuel and air. By proper disposition of the eccentric passageways the present invention attains counter rotation of the air and gas 'and thus assures thorough mixing and intermingling of the gas and air in the combustion zone. Moreover, the present invention spaces the eccentric passageways away from the cornbustion zone and thus protects the rotation-imparting equipment from the tremendous heat in the combustion zone. Further, the present invention provides adjustable valves, some of which are in the form of movable dampers, to regulate and determine the air-fuel mixtures. These adjustable valves also are spaced from the heat of the combustion zone and thus they are protected against jamming, burning and excessive corrosion.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing FIG. l is a cross sectional view of combustion apparatus embodying the principles and teachings of the present invention, and it is taken along the plane indicated by the line l-l in FIG. 2,

FIG. 2 is a cross sectional view of the combustion apparatus of FIG. l and it is taken `along the plane indicated by the line 2 2 of FIG. l,

FIG. 3 is a cross sectional view of the combustion apparatus of FIG. l and it is taken along the broken plane indicated by the line 3 3 in FIG. l,

FIG. 4 is a side elevational view of the `solenoid valve and the master adjusting valve for the fuel conducted to one nozzle of the combustion apparatus of FIG. 1, and

FIG. 5 is a schematic view of the valves for the alternately used fuels of a combustion apparatus and of a thermostatic switch that selectively connects those valves to a pressure-responsive switch.

Referring to the drawing in detail, the numeral 10 denotes a metal cylinder which has a radially directed ange 12 at one end thereof. The flange 12 can be secured to the wall of a rebox by bolts, rivets, welding or by brickwork and cement. The cylinder 10 may be lined with fire brick or other refractory material but preferably is equipped with an inner cylinder 14 which is spaced from the outer cylinder 10 to define a Water jacket 16. Suitable openings and plugs will be provided to fill and to slush out the water jacket 16, and suitable piping can be provided to connect that Water jacket with the boiler being heated by the tirebox. The cylinder 10 constitutes a combustion throat which will confine fuel and air from a combustion head and conduct that fuel and air to the rebox, intimately intermingling that fuel and air and burning it completely as it does so. The combustion Vhead is viewed from the lefthand end in FIG. l.

throat will be very small compared to the size of customarily used reboxes and combustion chambers; for example, the combustion throat can be as small as eight inches in diameter and as short as twelve inches and still provide one hundred boiler horsepower. A combustion head is connected to the combustion throat, and that combustion head includes a metal cylinder 18. The metal cylinder 18 has the same inner diameter as the cylinder 14. A ange 20 on the cylinder 18 is securable to the lefthand end of the combustion throat by bolts 22; and those bolts will seal the righthand end of the combustion head to the lefthand end of the combustion throat. An end wall 24 closes the lefthand end of the cylinder 18, and that end wall will be welded to the cylinder 18. A tube 26, which is large enough to accommodate the hand of a human being is welded to the cylinder 18, and an opening 27 is provided in the cylinder 8 to permit the interior of the tube 26 to communicate with the interior of the cylinder 18. An annular cap 28 is provided for the tube 26 and threads on the tube and cap will permit a tight seal between that tube and cap while permitting separation of the cap from the tube. Two annular gaskets 29 are disposed within the cap 28, and they are on opposite sides of a glass pane 30 held in that cap. The pane 30 permits inspection of the interior of the cylinder 18. The tube 26 makes it easy for the operator of the combustion apparatus to thrust his hand through the tube 26 and into the cylinder 18 to make any adjustments that may be necessary. Moreover, the tube 26 and the pane 30 make it possible to visually inspect the operation of the burner.

An opening 32 is provided in the side of the cylinder 1:8. A light-sensitive scanning device can be placed in register with the opening 32 and held there by a coupling pipe which is welded to the exterior of the cylinder 18. One such light-sensitive scanning device is disclosed in E. Craig Thomson Patent 2,624,398 which issued January 6, 1953, and another such scanning device is shown in my patent application entitled Controls for Combustion Apparatus which was filed May 1, 1953, and bears Serial No. 352,508, and which issued September 10, 1957, as Patent No. 2,805,652. Either of those scanning devices can be used with the combustion head of the present invention, but neither of those scanning devices forms a part of the present invention.

A metal cylinder 34 which is shorter than the cylinder 18 and which has a smaller diameter is welded to the end wall 24 of the combustion head. This cylinder is coaxial with and is encircled by the cylinder 18. An inwardly extending7 annular iiange 36 is formed on the righthand end of the cylinder 34. This annular flange will preferably be cut from a plate of metal and welded to the righthand end of the cylinder 34. The cylinders 18 and 34 will define and precisely predetermine an annular nozzle from which fluid can issue. The inwardly directed flange 36 will coact with the exterior of a cylinder 66 to define a second precisely predetermined nozzle the uid. The cylinder 66 will have its lefthand end extending through a circular opening in the end wall 24, and the exterior of the cylinder 66 will be welded to the portions of the wall 24 which deiine that circular opening. A portion of the lefthand end of the cylinder 18 is cut away at 38 to accommodate a passageway 4l). The righthand wall of the passageway 40 will be welded to the cylinder 18 and the upper end of the lefthand wall of the passageway 4t) will be welded to the cylinder 34, and the lefthand wall of the passageway 40 will also be welded to the cylinder 18, all as shown by FIG. 2. The end wall 24 of the combustion head will constitute the rear wall of the pasageway 40 and the front wall of that passageway will be welded to the cylinder 18. The passageway 48 will direct fluid into the annular area be- -tween the cylinders 18 and 34 and will cause that iluid to rotate in a counter-clockwise direction as the combustion The 6 combustion head is generally denoted lby the numeral 146.

The cylinder 18 is cut away as at 42 and the cylinder 34 is cut away as at 43 to accommodate a passageway 44. The upper edge of the lefthand side of the passageway 44 is welded to the cylinder 34 and the cylinder 18 is Welded to that lefthand side of the passageway 44 at a point below the upper end of that wall, all as shown by FIG. 2. The upper edge of the righthand wall of the passageway 44 is welded to the cylinder 66 and the cylinders 34 and 18 are welded to the righthand wall of the passageway 44 at points below that upper edge, all as shown by FIG. 2. The passageway 44 will have the end wall 24 as the rear wall thereof, and the front wall of that passageway will be welded to the cylinders 18 and 34. The passageway 44 will conduct tluid to the annular space between the cylinders 34 and 66 and will cause that fluid to rotate in a clockwise direction as the combustion head is viewed from the lefthand end in FIG. l. A separator 45 extends between and isolates the passageways 40 and 44 from each other above a point spaced above the bottoms of the passageways 40 and 44. The bottoms of the passageways 4t) and 44 will be connected, by a duct, not shown, to a motor operated blower, not shown. When the blower B is operating it will force uid through the passageways 48 and 44 and cause the fluids to rotate in opposite directions and to issue from the nozzles at the righthand ends of the cylinders 18, 34 and 66 in counterrotating directions. The annular space between the cylinder 18 and the cylinder 34 is larger than the annular space between the cylinder 34 and the cylinder 66 and the passageway 40 is larger than the pasageway 44.

Two channels 46 are mounted in the passageway 44 and the anges of those channels support an adjustable valve 48 in the form of an L-shaped damper. Similarly two channels 50 are mounted on the side walls of the passageway 4t) and the iianges of those channels support an adjustable valve 52 in the form of an L-shaped damper. The free ends of adjustable valves 48 and 52 are held in adjusted position, relative to that wall of passageways 44 and 40 which is opposite to the end wall 24, by nuts 56 and 57 which are mounted on threaded studs 54 and 55. These studs are welded to the end wall 24, and adjustment of the positions of the nuts 56 and 57 on those studs will shift the adjustable valves 48 and 52 transversely of passageways 44 and 40' and thereby determine the sizes of the openings defined by the free ends of valves 48 and 52 and the adjacent wall of the passageways 44 and 40; and the sizes of those openings will determine how much of the air supplied to the common entrance of passageways 44 and 48 will pass through each of those passageways. Proper setting of the nuts 56 and 57 on the studs 54 and 55 will provide the desired division between the air passing to the passageways 44 and 401 and thus to the nozzles deiined by the cylinders 34 and 66 and by the cylinders 18 and 34. A pipe 58 extends through the end wall 24 of the combustion head and has its other end welded to the forward wall of the passageway 44. A plurality of openings 68 are drilled in the upper side of the pipe 58 and those holes serve as jets for combustible fluid. This uid may be natural gas, water gas, butane, propane or the like. The lefthand end of the pipe 58 will be connected to a pipe S9 that extends from a manually adjustable valve 61. The manually adjustable valve in turn is connected to an electrically operated valve 63 that is connected by a pipe 65 to a suitable source of combustible uid. The manually adjustable valve 61 can be set to determine the rate of flow of gas into the pipe 58, and the electrically controlled valve '63 will determine when gas will iiow to the pipe 518.

The numeral 62 denotes a pressure responsive switch and that switch has an open-ended tube 64 extending therefrom into the passageway 40. The switch 62 is normally open but will close its contacts Whenever the pressure in the passageway 40 adjacent the open ended pipe v48 and 52 except that they will be smaller.

64 rises to a predetermined value. Switch 62 will be connected in the circuit of the elctrically operated valve 63, which is normally closed, and Will act to open that valve only after the air pressure in the passageway 40 attains a predetermined value. Such an arrangement assures full air volume in the combustion area before the combustible fluid is permitted to enter the pipe 58, and thus the present invention avoids any waste of combustible fluid that would occur if that fluid entered the combustion area before a full supply of supporting air was in that chamber.

The cylinder 66 has the lefthand end thereof closed by an end wall 70, and it has a flange 68 of annular form welded to the righthand end thereof. The cylinder 66 encircles a cylinder .'72 which is also secured to the end wall 70. The righthand end of the cylinder 72 has the exterior thereof spaced from the annular flange 68 on cylinder 66 to define a nozzle of predetermined area. The in- 'terior ofthe righthand end of the cylinder 72 has an annular recess 74 formed therein and that recess delines a nozzle of predetermined area. The cylinder 66 is cut away ,at points 76 and the cylinder '72 is cut away at points 73 to accommodate the end of passageway Si). That end of the passageway 80 is welded to the cylinder 72, and the sides of the passageway 80 are welded to the cylinder 66. The

4.passageway 80 introduces air from a blower B into the cylinder 72 at one side thereof and causes that air to move circumferentially through that cylinder. The cylinder 66 Iis cut away at points 82 to accommodate the end of the passageway 84. That end of the passageway 64 is Welded to the cylinder 66 and is also welded to the cylinder 72. The passageway 84 introduces a mixture of air and combustible uid into the cylinder 66 and causes that air and combustible uid to move circumferentially of that cylinder. The directions of rotation of the air in `cylinder 72 and of the air and combustible tiuid in cylinder 66 are opposite to each other, thus providing a counter rotation of the uids in the two cylinders. A partition 86 separates the two passageways S0 and S4 at a point spaced to the left of the righthand end of those passageways.

Two channels 88 are secured to the wall of the passageway 84 and the llanges of those channels support an adjustable valve 90 in the form of an L-shaped damper. Two channels 92 are mounted on the walls of the passageway 80 and the iianges of those channels support an adjustable valve 94 in the form of an L-shaped damper. The dampers 90 and 94 will be similar to the darnpers The dampers 90 and 94 will be adjusted by nuts mounted on threaded studs secured to the end wall '70. Adjustment of the settings ofthe dampers 90 and 94 will predetermine the relative amounts of air introduced into the cylinders 66 and 72. The blower B will be attached to the righthand ends of the passageways 86 and 34 and will positively force the air through the passageways S and 64 and through the cylinders 72 and 66.

A pipe 96 extends through the end wall 70 and is secured to the forward wall of the passageway 84. That forward wall will be in the plane of the rear wall 24 of the cylinder 18. A manually operated valve, similar to valve 61, and an electrically responsive valve, similar to valve 63, will be serially connected to the outer end of `the pipe 96. The manually operable valve, similar to valve 61, will be adjusted to determine the amount of combustible iiuid that can flow into the pipe 96 and the electrically kresponsive valve, similar to valve 63, will respond vto a pressure-operated switch, similar to the switch 62, which will be mounted in the passageway 80. That electrically responsive switch will prevent liow of combustible fluid into the pipe 96 until a predetermined pressure of air is established in the passageway S6. A plurality of openings 98 will be drilled in the pipe 96 to 'serve as outlets for combustible liuid. This combustible 'iiuid willxbe carried through the passageway 84 by the air in that passageway and will ow through the cylinder 66 to the combustion area at the righthand end of the combustion head.

A smooth walled pipe 106 extends through the end wall '70 and is welded to that wall. An annular groove 102 is formed in the exterior of that pipe adjacent the righthand end thereof and that annular groove delines a radially extending projection 104 at the righthand end of that pipe. A number of circumferentially spaced openings 106 extend through from the smooth walled interior of the pipe 106 to the annular recess or groove 102 in the exterior of pipe 106. A larger diameter pipe 103 is telescoped over the righthand end of the pipe and is welded to that pipe. Fthe interior of that larger diameter pipe 108 is cut away to a predetermined dimension. This cut away portion coacts with the annular groove 16.2 to define an annular passageway and coacts with the radially extending projection 104 to define an annular nozzle of predetermined area. The righthand end of the pipe 108 extends axially beyond the righthand end of the pipe 100. Moreover, the pipe 108 extends radially outwardly beyond the outer diameter of the pipe 100. A pipe 110 of still larger diameter is telescoped over the exterior of the pipe 168 and is welded to that pipe. This pipe extends both axially and radially beyond the pipe 163. The radially extending projection 104 on the pipe 106 and the cut away portion of the pipe 108 define an annular nozzle for a pilot. The pipe 110 serves to protect that pilot by deflecting air outwardly from that pilot and by shielding that pilot from that air.

The lefthand end of the pipe 166 extends into a fortyiive degree junction 112. A nipple 114, which is suitably connected to a source of combustible gas, extends downwardly at forty-tive degrees from the junction 112 and a manually adjustable valve, similar to the valve 61, and an electrically responsive valve, similar to the valve 63, will be serially connected to the nipple 114. Adjustment of the manually operable valve will control the amount of combustible fluid that enters the pipe 100 and the electrically responsive valve will determine when that cornbustible fluid enters the pipe 100. The electrically responsive valve will be controlled by a circuit which includes the spark-forming electrodes 128. A blower 116 is connected to the end of the pipe 100 by an intervening coupling pipe 118, and it will force air and combustible iiuid through the pipe 106 and out the righthand end of that pipe. A small portion of the admixed air and combustible liuid will pass through the openings 106 into the annular passage defined by the groove 102 and the cut away lnterior of the pipe 10S. This premixed combustible fluid and air will then issue through the nozzle of annular form defined by the radially extending projection 104 and the cut away interior of the pipe 108. The rest of the premixed air and combustible fluid will issue rn a stream from the righthand end of the pipe 100. When the pilot is lighted, it will have an annular iiame at the annular orice delined by the projection 104 on pipe .100 and by the cut away portion of the pipe 108, and it will also have a flame extending outwardly from the righthand end of the pipe 100. That liame will preferably be from one to two feet or longer in length and it will serve to ignite the combustible fluid issuing from the cylinder 66 or the cylinder 34.

A nozzle 120 for a non-gaseous fuel such as oil or powdered coal or the like, is disposed within the pipe 100. This nozzle will provide a counterclockwise rotation of the non-gaseous fluid fuel issuing therefrom, as that rotation is determined from the lefthand end of the combustion head of FG. l and as that rotation is shown by arrows within the pipe 100 in FIGS. 2 and 3. The nozzle 120 is supported by the pipe 122 which extends through the pipe 16d to a point exteriorly of the end plate 70 and then passes through the wall of the pipe 100. An electrically operated valve 123 is connected to the pipe 122, and that valve selectively prevents or permits non-gaseous fuel to flow to the nozzle 120. A weld will provide an air tight joint between the pipe 122 and the pipe 100, and that weld will hold the pipe 122 and the nozzle 121) concentric with the pipe 108. The fluid fuel from the nozzle 126 will pass through the pilot llame and will pass through the llames supported by the combustible fluid from cylinder 66 and the air from cylinder 72. That latter flame will preferably be from three to four feet or longer in length and will subject the uid fuel from nozzle 128 to rapid and high heating. Moreover, that llame will cause turbulence and will break up the fluid fuel from the nozzle 120 and intimately admix it with the air from the cylinder 72 and from the cylinder 18 to provide prompt and complete burning of that fuel.

Insulators 124 extend through the wall of the cylinder 18 and are sealed to that wall by suitable seals 126. The insulators 124 carry and support the electrodes 128 which are connected to leads 130. The electrodes 128 are spaced apart to provide a gap and when a spark bridges that gap that spark will ignite the combustible fluid in the combustion head. The wires 130 will be connected to a suitable source of high voltage electricity to assure positive bridging of the gap between the electrodes 128.

Patent No. 2,805,652 which was granted September 10, 1957, for Water -Level Responsive Controls for Combustion Apparatus discloses a thermostatic switch that alternately connects one or the other of two high ilre fuel valves to a pressure-responsive switch; and such an arrangement is used to alternately connect the high lire fuel valves 63 and 123 to the pressure-responsive switch 62. As shown in FIG. 5, the thermostatic switch 125 alternately connects the fuel valve 63 or the fuel valve 123 to the pressure-responsive switch 62. This means that whenever the nozzle 120 is issuing non-gaseous fuel the nozzle defined by annular flange 36 will not be issuing any fuel, and vice versa.

In using the combustion apparatus provided by the present invention, the combustion throat 11D is secured to the firebox of a boiler, furnace or other heating device and the combustion head is bolted to the combustion throat. Thereafter, a spark is caused to bridge the gap between the spaced electrodes 128 and the electrically controlled valve for the pilot opens and permits combustible iluid to enter the pipe 160. Simultaneously, the blower 116 will start and will force the pre-mixed air and combustible iluid outwardly from the pipe 100 and outwardly from the annular nozzle defined by the radially extending projection 164 and the cut away section of the pipe 168. This mixture of air and combustible lluid will be ignited by the spark that bridges the gap between the spaced electrodes 128. The manually operable valve between the electrically operable valve and the nipple 114 will then be adjusted to provide the desired air-combustible fluid ratio to attain full burning of that fluid to carbon dioxide with a minimum of excess air. An adjustable valve in the form of a damper 119 is provided between the blower 116 and the pipe 101) to control the volume of air delivered to the pipe lll). This damper is set so that pilot is between one and two feet or longer in length. Once the pilot has been adjusted, the blower B connected to the passageways 8l! and 84 is started and after the air pressure in the passageway 80 has actuated the pressure-responsive switch, similar to the pressure-responsive switch 62, that switch will act to open the electrically responsive valve for the combustible fluid. That iluid will then pass into the pipe 96 and out of the openings 98 and be carried into the cylinder 66. The manually adjustable valve connected to the end of the pipe 96 will then be adjusted to assure full conversion of that combustible fluid to carbon dioxide with a minimum of excess air. The dampers 91) and 94 will be adjusted and tightly held in place to assure the proper distribution of the air between the passageways 80 and 84. The combustible .fluid and air issuing from the cylinders 66 and 72 will establish a low lire which will have a length of from three to four feet or longer; the length being determined by the settings of the dampers 90 and 94. Once the low fire has been regulated, it can be extinguished by stopping the blower motor; and thereafter the pressureresponsive switch, similar to switch 62, will permit the electrically-responsive fuel valve to close and halt the flow of fuel to pipe 96. Thereafter the blower B connected to the passageways 4G and 44 can be energized, and when the pressure in the passageway 40 rises to the point where it closes the pressure-responsive switch 62, the electrically responsive valve 63 will open. This will permit combustible fluid to enter the pipe 5S and issue from the holes 60. The air in passageway 44 will carry that combustible fluid to the righthand end of the cylinder 34. This mixture of air and combustible fluid will be ignited by the pilot and will establish a high re extending for from six to eight feet or longer through the combustion throat 10 and into the firebox of the boiler or furnace. The valve 61 may be adjusted to determine the desired volume of combustible lluid and the dampers 48 and 52 will be adjusted to effect the desired distribution of air between the passageways 40 and 44 and to attain full combustion of the fuel without too much excess air. Once the proper adjustment of the dampers 52 and 48 and the valve 61 have been attained, the blower B to the passageways 4t2 and 44 can be shut off and the pressure-responsive switch 62 will then shut olf the flow of combustible iluid. The present invention provides three regulated volumes of combustible fluid and three regulated volumes of supporting air therefor. Moreover, the present invention makes it possible to individually divide the supporting air for the high fire and low fire. In this way, it is possible to attain precise control of the burning of the combustible lluid at full capacity and at intermediate capacity as well as when the pilot alone is operating. The overall thermodynamic eillciency can be set and maintained at very high levels.

In operation, the pilot is ignited and then operates continuously. The low re will be controlled, preferably by a steam pressure control switch of usual design and operation, and will cycle according to the demands of the boiler or furnace. When the low fire is demanded, the blower B connected to the passageways and 84 will start and as the pressure in the passageway 80 rises the pressure-responsive switch similar to the pressureresponsive switch 62 will close and permit combustible fluid to enter the pipe 96. The air will carry the combustible fluid through the combustion head and into the combustion throat and that air and combustible fluid will burn vigorously and thoroughly. The combustible fluid in the low fire is ignited by the pilot and it is rotating in a counterclockwise direction while the supporting air therefor is rotating in a clockwise direction as viewed from the left in FIG. 1. The interaction of the air and combustible iluid shreds the customary raw gas cone and the customary cone of aldehydes and alcohols and carbon monoxide and provides a homogeneous llame which burns quickly and at high temperature. The low lire flame will be confined closely by the combustion throat and that throat will force the air and combustible fluid and products of combustion to intermingle thoroughly and attain full and immediate burning ofthe combustible iluid to carbon dioxide. If the demand on the boiler or furnace is low, the low fire will be able to satisfy it and will then be cut olf by the steam pressure control or other control mechanisms. If the demand is too great for the low lire, the blower B connected to the passageways 46 and 44 will be energized and will increase the air pressure in the passageway 40. This increase in air pressure will cause the contacts of the switch 6^ to close and will open the electrically operated valve 63. Combustible iluid from the line 65 will then pass into the pipe 58 and out of the openings 66. This combustible fluid will be carried by the air through the passageway 44 and into the cylinder 34. The air issuing from the spaanse cylinder 18 and the combustible fluid and premixed air issuing from the cylinder 34 will be ignited by the low fire and will promptly burn. The combustible fluid issuing from the cylinder 34 will be rotating in a direction opposite to that of the combustible fluid issuing from the cylinder 65 and the air issuing from the cylinder f8 will be rotating in a direction opposite to that of the air issuing from the cylinder '72. Moreover, the fluids issuing from the cylinders i8, 34, 66 and 72 will alternate in direction. rIlle overall effect is a complete shredding and breaking up of the raw fuel mantles and the partially burned fuel mantles experienced with most burners. A completely homogeneous and wildly turbulent flame results which assures full and complete combustion to carbon dioxide in a very short length. As the flame passes from the combustion head and into the combustion throat it is held and confined to a very small volume and is forced to thoroughly intermix its component parts and thus assure full combustion.

The nozzle 12d and the pipe 122 will be kept cool both by the passage of the air from the blower llo to the pipe 100 and by the flow of air through the cylinder 72 from the passageway Sil. As a result, the nozzle 12@ will yremain relatively cool. If the combustible fluid available for the high fire is on an interruptible basis, and if the outside temperature becomes low enough to cause interruption of the combustible fluid for the high fire by causing the lower end of the movable contact of the thermostatic switch 12S to shift out of engagement with the fixed contact connected to the valve 63 and into engagement with the fixed contact connected to the valve 123, the valve 123 which controls the flow of uid fuel through the pipe l22 and the nozzle 120, will open. This will cause the oil or powdered coal to pass through the pilot and through the low fire flames and be heated and ignited by those flames. The nozzle 120 is of usual design and construction and will cause the fluid fuel to rotate in a counterclockwise direction as that direction is viewed from the lefthand end of the co-mbustion head of FIG. 1, as indicated by the arrows within pipe lill) in FIGS. 2 and 3. This will be opposite to the direction of flow of air in cylinder 72 and will cause countercurrent rotation. The fuel from the nozzle 120 will unite with the fuel of the pilot and of the low fire to provide a ythoroughly homogeneous flame of short length and high intensity. The air for the fuel issuing from the nozzle 120 will be supplied by the cylinder ll8 because the closing of the valve 63 in the fuel line to pipe 58 will not interrupt the operation of the blower connected to passageways 40 and 44. The fuel from the nozzle 120 will operate on a cycle basis depending upon the demand of the boiler or other heating device, in the same way that the fuel from the pipe 58 operates on a cycle basis. Preferably the low fire will operate before the high fire or the nongaseous fuel fire operates and will continue beyond the time when the high fire or the non-gaseous fuel fire cuts off. While fuel from the nozzle 120 is being burned, the cylinders 18 and 72 are kept cool by the air flowing through them. In this way, the present invention protects the inactive nozzles from the effect of the flame in the combustion head. The present invention also protects the adjusting devices from heat by placing them at a distance from the flame. Thus, the adjustable darnpers are in the cool region of the combustion head `and the valves for the combustible fluid and for the nongaseous fluid fuel are in cool areas external of the combustion head. l

The present invention can utilize combustible fluids .under low pressure because the air flowing past the openings in the pipes 58 and 96 and flowing past the nipple 114 will Vinspirate the combustible fluid. For example, the combustible fluid for the pilot in a one hundred horsepower boiler set up can be as low as three quarters of an inch water column and still provide a pilot of from ,one to two lfeet or longer in length. Similarly, the cornbustible fluid for the low fire and high fire may have a pressure of as little as one inch water column and still provide flames of approximately four feet and approximately eight feet in length respectively for that boiler set up. This is very desirable because it enables full pressure regulation of the combustible fluid by commercially available pressure regulators between the source of supply of the combustible fluid and the electrically responsive valves which control the flow of combustible fluid to the pilot, low fire and high fire.

The smooth-walled pilot nozzle at the inner end of the pipe lill? has a large capacity for its relatively small diameter. That pilot has about three times the capacity of prior pilot nozzles which have inserts to reduce the inner diameter of those nozzles.

Whereas the drawing and accompanying description have discloged several preferred embodiments of the present invention, it sho-uld be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

l. Apparatus for burning combustibles which comprises a tube of cylindrical configuration that has an outlet end, a second tube of cylindrical configuration of lesser diameter than the first said tube that is telescoped within and that is fixedly held relative to the first said tube, said second tube having an outlet end adjacent said outlet end of the first said tube, said outlet ends of said tubes defining between them an annular space of predetermined cross sectional area, a passageway conducting fluid to the interior of the first said tube for movement to said annular space defined by said outlet ends of said tubes, and a generally flat plate that is annular in configuration and is secured to the first said tube adjacent the said outlet end thereof and that extends inwardly but terminates short of said second tube, the inner periphery of said annular plate coacting with the outer periphery of said second tube to define an annular nozzle through which said fluid can issue, said annular nozzle having an outer diameter larger than the outer diameter of said second tube but smaller than the inner diameter of the first said tube whereby the cross sectional area of said annular nozzle is smaller than the cross sectional area of said annular space and whereby said flat plate forces said fluid passing through said annular nozzle to move inwardly adjacent the said outlet end of said second tube, the inner diameter of said annular nozzle being substantially the outer diameter of said second tube whereby part of said fluid passing through said annular nozzle moves axially immediately before it passes through said annular nozzle, said annular plate being short in the axial direction to provide a short annular nozzle for said apparatus for burning combustibles.

2. Apparatus for burning combustibles which comprises a tube having an outlet end, a second tube of lesser cross section than the first said tube that is telescoped within and that is fixedly held relative to the first said tube, said second tube having an outlet end, said outlet ends of said tubes defining between them an annular space of predetermined cross sectional area, a passageway conducting fluid to the interior of the first said tube for movement to said annular space defined by said outlet ends of said tubes, an annular plate that extends transversely of the first said tube and that extends inwardly but terminates short of said second tube, the inner periphery of said annular plate coacting with the outer periphery of said second tube to define an annular nozzle through which said fluid can issue, said annular plate being adjacent the outlet end of the first said tube, and a second passageway that conducts a second fluid to said second tube for movement to the said outlet end thereof, said annular nozzle having an outer dimension larger than the outer dimension of said second tube but smaller than the inner dimension of the first said tube whereby the cross sectional ,area of said annular nozzle is smaller 13 than said predetermined cross sectional area and whereby said annular plate directs the first said fluid inwardly adjacent said second tube.

3. Apparatus for burning combustibles which comprises a central nozzle for non-gaseous fluid fuel, a tubular pilot nozzle that encircles said nozzle for non-gaseous fluid fuel and that has an outlet end which projects outwardly beyond said nozzle for non-gaseous fluid fuel, a tubular nozzle for gaseous fuel that encircles said nozzle for non-gaseous fluid fuel and said pilot nozzle and that has an outlet end which projects outwardly beyond Said nozzle for non-gaseous fuel and said outlet end of said pilot nozzle, a tubular nozzle for air that encircles said nozzle for non-gaseous fluid fuel and said pilot nozzle and that has an outlet end which projects outwardly beyond said nozzle for non-gaseous fluid fuel and said outlet end of said pilot nozzle, a valve that is intermediate said nozzle for said non-gaseous fluid fuel and a source of non-gaseous fluid fuel and that intermittently opens to supply non-gaseous fluid fuel to said nozzle for non-gaseous fluid fuel, a passageway connected tangen tially to said nozzle for gaseous fuel to deliver pre-mixed air and gaseous fuel to said nozzle for gaseous fuel and to cause said pre-mixed air and gaseous fuel to follow a substantially helical path as it moves through and issues from said nozzle for gaseous fuel, a second valve that intermittently opens to supply gaseous fuel to said passageway, a blower, a second passageway connected tangentially to said nozzle for air to deliver air from said blower to said nozzle for air and to cause said air to follow a substantially helical path as it moves through and issues from said nozzle for air, the helical path for said air being oppositely directed to said helical path for said pre-mixed air and gaseous fuel, the air from said nozzle for air supporting the combustion of said nongaseous fluid fuel whenever the valve for said non-gaseous fluid fuel is open and supporting the combustion of said pre-mixed air and gaseous fuel when said second valve is open, said pilot nozzle maintaining a continuous pilot llame to insure ignition of said non-gaseous fluid fuel and of said pre-mixed air and gaseous fuel, said non-gaseous fluid fuel passing through and being heated and ignited by said pilot flame before it reaches the air from said nozzle for air.

4. Apparatus for burning combustibles which comprises a nozzle for non-gaseous fluid fuel, a tubular pilot nozzle that encircles said nozzle for non-gaseous fluid fuel, a tubular nozzle for air that encircles said nozzle for non-gaseous fluid fuel and said pilot nozzle, a tubular nozzle for gaseous fuel that encircles said nozzle for non-gaseous fluid fuel and said pilot nozzle and said nozzle for air, a second tubular nozzle for gaseous fuel that encircles said nozzle for non-gaseous fluid fuel and said pilot nozzle and said nozzle for air and the first said nozzle for gaseous fuel, a second tubular nozzle for air that encircles said nozzle for non-gaseous fluid fuel and said pilot nozzle and the first said nozzle for air and the first said and said second nozzles for gaseous fuel, a valve that is intermediate said nozzle for said nongaseous fluid fuel and a source of non-gaseous fluid fuel and that intermittently opens to supply non-gaseous fluid fuel to said nozzle for non-gaseous fluid fuel, a blower, a passageway connected tangentially to the first said nozzle for air to deliver air from said blower to the first said nozzle for air and to cause said air to follow a substantially helical path as it moves through and issues from the first said nozzle for air, a second passageway connected tangentially to the first said nozzle for gaseous fuel to deliver gaseous fuel to the first said nozzle for gaseous fuel and to cause said gaseous fuel to follow a substantially helical path as it moves through and issues from the first said nozzle for gaseous fuel, a second valve that intermittently opens to supply gaseous fuel to said second passageway, the helical path for said air being oppositely directed to said helical path for said gaseous A 14 fuel in the first said nozzle for gaseous fuel, the air from the first said nozzle for air supporting the combustion of the gaseous fuel from the first said nozzle for gaseous fuel to provide a low re flame, a second blower, a third passageway connected tangentially to said second nozzle for air to deliver air from said second blower to said second nozzle for air and to cause said air to follow a substantially helical path as it moves through and issues from said second nozzle for air, a fourth passageway connected tangentially to said second nozzle for gaseous fuel to deliver gaseous fuel to said second nozzle for gaseous fuel and to cause said gaseous fuel to follow a substantially helical path as it moves through and issues from said second nozzle for gaseous fuel, a third valve that intermittently opens to supply gaseous fuel to said fourth passageway, the helical path for the air in said second nozzle for air being oppositely directed to the helical path for the gaseous fuel in said second nozzle for gaseous fuel, the air from said second nozzle for air supporting the combustion of said non-gaseous fluid fuel to provide an alternate high fire flame whenever the valve for said non-gaseous fluid fuel .is open and supporting the combustion of the gaseous fuel from said second nozzle for gaseous fuel to provide a regular high lire flame whenever said third valve is open, said pilot nozzle maintaining a continuous pilot flame to insure ignition of said non-gaseous fluid fuel and of said air and gaseous fuels, said non-gaseous fluid fuel passing through and being heated and ignited by said pilot flame before it reaches the air from said second nozzle for air.

5. Apparatus for burning combustibles which comprises a pilot nozzle, a tubular nozzle for air that encircles said pilot nozzle, a tubular nozzle for gaseous fuel that encircles said nozzle for air and said pilot nozzle, a second tubular nozzle for gaseous fuel that encircles said pilot nozzle and said nozzle for air and the first said nozzle for gaseous fuel, a second tubular nozzle for air that encircles said pilot nozzle and said nozzle for air and the first said and said second nozzles for gaseous fuel, a pas"ageway connected tangentially to the first said nozzle for air to deliver air to the first said nozzle for air and to cause said air to follow a substantially helical path as it moves through and issues from the first said nozzle for air, a second passageway connected tangentially to the first said nozzle for gaseous fuel to deliver gaseous fuel to the first said nozzle for gaseous fuel and to cause said gaseous fuel to follow a substantially helical path as it moves through and issues from the first said nozzle for gaseous fuel, the helical path for said air being oppositely directed to said helical path for said gaseous fuel in the first said nozzle for gaseous fuel, the air from the first said nozzle for air supporting the combustion of the gaseous fuel from the first said nozzle for gaseous fuel to provide a low lire llame, a third passageway connected tangentially to said second nozzle for air to deliver air to said second nozzle for air and to cause said air to follow a sub tantially helical path as it moves through and issues from said second nozzle for air, a fourth passageway connected tangentially to said second nozzle for gaseous fuel to deliver gaseous fuel to said second nozzle for gaseous fuel and to cause said gaseous fuel to follow a substantially helical path as it moves through and issues from said second nozzle for gaseous fuel, the helical path for the air in said second nozzle for air being oppositely directed to the helical path for the gaseous fuel in said second nozzle for gaseous fuel, the air from said second nozzle for air supporting the combustion of the gaseous fuel from said second nozzle for gaseous fuel to provide a high lire llame, said gaseous fuel for the first said nozzle for gaseous fuel being premixed air and gaseous fuel, said gaseous fuel for said second nozzle for gaseous fuel being pre-mixed air and gaseous fuel.

6. Apparatus for burning combustibles whicheomprises a tube of cylindrical configuration that has an outlet end, a second tube of cylindrical conguration of lesser diameter than the lirst said tube that is telescoped within and that is xedly held relative to the rst said tube, said second tube having an outlet end, said outlet ends of said tubes dening between them an annular space of predetermined cross sectional area, a passageway conducting lluid to the interior of the first said tube for movement to said annular space delined by said outlet ends of said tubes, and a plate of annular configuration that is secured to the rst said tube adjacent the said outlet end thereof .and that extends transversely of the first said tube, the inner periphery of said annular plate extending inwardly but terminating short of said second tube to define an annular nozzle through which said fluid can issue, said annular plate having an inner diameter smaller than the inner diameter of the rst said tube whereby said annular plate forces said uid passing between said second tube and the inner periphery of said annular plate to move inwardly adjacent the said outlet end of said second tube.

References Cited in the `file of this patent UNITED STATES PATENTS Amsler Feb. 22, Anthony Nov. 8, Zander Feb. 19, Fischer July 19, Wetherbee Jan. 5, Moor Sept. 13, Mangold `Mar. 26, Kuhner Oct. 22, Dunham et al. July 7, Warrick I an. 25, Naab et al. July 25, Rickert Apr. 8, Kruger June 3, Crowe Dec. 28, Urquhart Ian. 11, Pattinson et a1. Feb. 14, Sweigart June 29,

FOREIGN PATENTS Germany Nov. 23,

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