US1654658A

US1654658A - Apparatus for burning liquid fuel

Info

Publication number: US1654658A
Application number: US45448A
Authority: US
Inventors: John H Mcilvaine
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-07-23
Filing date: 1925-07-23
Publication date: 1928-01-03
Anticipated expiration: 1945-01-03

Description

J. H. M ILVAINE APPARATUS FOR BURNING LIQUID FUEL Filed July 23, 1925 3 Sheets-Sheet l Jail. 3, 1928.

Jan. 3, 1928. 1,654,658

J. H. MCILVAINE APPARATUS FOR BURNING LIQUID FUEL Filed July 23, 19%5 3 Sheets-Sheet 2 a Jan. 3, 1928. 1,654,658

J. H. MCILVAINE APPARATUS FOR BURNING LIQUID FUEL Filed July 23, 1925 3 Sheets-Sheet 3 digs.

Patented Jan. 3, 1928.

UNITED STATES JOHN H. MOILVAINE, 61? LAKE FOREST, ILLINOIS.

APPARATUS FOR BURNING LIQUID FUEL.

Application filed July 23, 1925. Serial No. 45,448.

This invention relates in general to proportional mixers, and more particularly one designed for carbon burners, commonly known as oil burners; and While certain principles of my invention may be applied in the burningof any and all grades of fuel, the embodiment disclosed herein is intended for oil fuel of not lower gravity than 30 Baum. My invention' may be used for either industrial or domestic heating, its present application being to a furnace such as is used for heating the average home.

One of the objects of my invention is to improve the construction and operation of liquid fuel burners with the viewto economizing in fuel consumption, cost of operation, and maintenance. This is accomplished by securing more efiicient combustion and by employing a simple and novel operv broader aspect of my invention, however, the

flame may be either continuous or intermittent, either constant in amount, or variable. In the practical application of my invention and in its preferred embodiment oil and air are fed in proper proportions and in certain predetermined amounts by an electric motor connected to a centrifugal pump and a centrifugal fan through suitable pipes to a combustion chamber. In my co-pending applic-ation, Serial No. 67 9,467, filed December 8, 1928, I employ a variable speed motor for driving thefuel pump and air fan and by varying the speed of the motor I vary the fuel feed. The present application is, howi ever, confined primarily to the use of a constant speed motor for driving the fuel pump and air fan or blower and to the means whereby the fuel and air feeds are in proper roportions .to maintain a continuous eificient flame throughout a wide range of heats as applied to practically any installation.

use with liquid fuel or hydro- Some of the conditions and circumstances attending the use of the burner will better explain certain purposes and objects of my invention. The burner must be able to run at a flame sufficientl low so that practically no heat is given 0 on unseasonably warm days. The flame must be capable of rapid increase to give the proper amount of heat, in the event of a sudden drop of temperature, without blowing out. Also there must be a suificient number of intermediate positions to properly control the house temperature. The burner must have suflicient capacity to keep the house at the avera e temperature desired such, for example, as 0 F. with the lowest outdoor temperature; and a high efiiciency of combustion must be obtained at all loads. Moreover, outdoor variations. of temperature and wind must not influence. the amount of air supplied or the efficiency will be lowered due toeither incomplete combustion or excess air. The burner should be adapted to manual control at the mae chine or remote control by means of a suitable thermostat, preferably one having three or more contact positions. Some of the advantages of the continuous variable flame will be readily recognized and appreciated. Inasmuch as the motor runs continuously there is practically no need for the 'usual.

starting coils, switches, and auxiliary devices and mechanisms invariably required for starting and stopping; consequently, the present construction is free from man of the troubles followin from the use 0 intermittently operate oil burners. High combustion efiiciency is also obtained y reason of the continuous flame. In the first place, at no time is any more heat being delivered into the heater or boiler than is necessary, with resulting relatively low temperatures of the stack gases at all loads, which means that the gases have given up more heat to the heater or boiler because they are never forced through faster than necessary. Also there are no idle periods as obtained with an intermittent flame and as a result the efliciency is increased. This is evident when compared with an intermittently operating system in which during a considerable period of tlme after the flame starts, the combustion chamber, boiler and plied for proper combustion; and, after the intermittent flame ceases, the boiler and fiues are very hot and continue to draw cold air through with resultant loss of heat. Another decided objection to the latter type is that continually changing from a mere pilot light to a very high heat and back again, sometimes many times a day, puts a great strain on the heater or boiler and flues through rapid expansion and contraction, thereby causing cracks, leaks and displacements of the parts affected by the heat. The elimination of the gas pilot light or the electrical or combination ignition, absolutely prevents explosions through delayed ignition or blowing out of the pilot light when the gas pressure is low. Still another advantage of the present invention as compared with the prior intermittently operating types of oil burners is that the number of mechanical parts is considerably reduced and the mechanism greatly simplified. It is believed that the present invention is a marked improvement over gravity type burners,

especially in that more efiicient combustion is obtained through positive feed of air at all loads which is little affected by changes of atmospheric conditions, as will be ex plained later.

In connection with the continuous flame type of burner I have aimed especially to provide a simple and practical means for controlling and regulating the amounts of the air and fuel feeds. This control is characterized by its adjustment features whereby in its application to practically any heater or boiler it may be adjusted and setto deliver suchvolumes of air at the different loads as to produce eflicient combustion at all times. This is very desirable since in practice there are hardly any two heaters or boilers in which the conditions affecting combustion are alike.

Other objects and attendant advantages will be appreciated by those skilled in this art as the invention becomes better under- .stood by reference to the following description when considered in connection with the I accompanying drawings, in whichlg. 3, is a similar view looking at the left hand side of Fig. 2;

Fig. 4 is an enlarged side elevation of the blower and air shutter control;

as from a storagetank (not shown) to a service tank 11. From this tank the oil flows by gravity through a shut-off valve 12, a strainer 13, and pipe 14 to a safety valve 15 adapted to shut off the flow to the burner in case of any failure of the flame as will be discussed later. The oil then flows through a pipe 15 to a float valve designated generally by 16 mounted on a suitable frame 17 and serving to maintain the oil at a constant level. From here the oil flows by gravity through a pipe 18 to a centrifugal pump 19 which is driven through a coiled spring connection 21 by a constant speed electric motor 22. Both the pump and motor are mounted on the frame 17 in the operative relation shown. The pump 19 is preferably of a special construction embodying the principles disclosed and claimed in my co-p'ending application, Serial No. 7 0,754, filed November 23, 1925. This pump has an oil inlet through the pipe 18 and an outlet through the upstanding pipe 23, and a rotary impeller 24. The revolving of the impeller raises the oil pressure to a head in the outlet pipe 23 and in a standpipe 25, as for example, to the level indicated by 26. Because the pump delivers a very small amount of oil as compared to its full capacity with unrestricted flow, the churning of the impeller causes the formation of small air bubbles which, being lighter than the oil, collect at the center of the impeller blade and tend to reduce the pressure of oil at the pump outlet. Provision is made for allowing escape of this trapped air as explained'in my co-pending application claiming this pump construction. The pump friction load on the motor is practically eliminated by building the bearing for the impeller shaft without a stuffing box, which allows a ver small amount of-oil t0 flow continuously a ong the shaft and out of the hearing at a drip point 27. The further course of this drip will be discussed later. The oil rises in the outlet pipe 23 by the action of the centrifugal pump and passes into the main standpipe 25 through a horizontal overflow pipe 28 which is higher than the level'of the oil in the float valve 16. Thus, when the motor stops, the pump also stops, the oil level drops in pipe 23 below the rises in the standpipe until it reaches the above-mentioned point 26 above the overflow pipe 28, predetermined by the diameter of the impeller, the speed of revolution of the motor and the level of oil in the float valve. This arrangement of standpipe pipe 29 and control valve 31 allows all the air, as far as the control valve, to escape through said standpipe, and likewise allows the escape of any bubbles of air' formed in the pump and thrown out by the impeller blades into the upstanding outlet pipe 23. The control valve governs the amount of oil fed to the burner and may consist of a globe type needle valve with a threaded stem 32 on which an adjustment wheel 33 is mounted. on this stem 32 is mounted for adjustable connection with the wheel 33, as by a set screw 30, a lever arm 34. through which the valve is connected to an air control shutter which will be presently described. From the control valve the oil flows through a pipe 35 which rises to an overflow delivery point 36 from which point it drops through a vertical delivery pipe 37 having a sharp delivery point 38 from which the oil drops'into the combustion-chamber designated generally by 39. The rise at the'overflow delivery point 36v allows a steady flow of oil and prevents gushing. Also the pipe 35 rises gradually to said overflow delivery point to allow the escape of air beyond the control valve 31. The purpose of the sharp delivery point 38 is to allow the oil to drop off into the combustion chamber 39 in a fine steady streanr even at a very low rate without breaking up into large bubbles which would cause an intermittent and jerky flame with poor combustion resulting. In order to prevent premature vaporization of the oil in the oildeliverypipes they are enclosed in the air delivery pipe 41 andalso in a vertically disposed portion 42 in which the vertical delivery pipe 37 is held centered so as not to come in contact with the air-delivery pipe which leads to the combustion chamber. The vertical oil-delivery pipe 37 .at its upper extremity may be vented by connecting through suitable pipes to theatmosphere at any suitable place, thus allowing the oil to flow freely by-gravity from the overflow point 36 to the sharp delivery oint 38 without any siphonic action; I pre er however, to have a lateral opening 43 facing into the column of air flowlng through .the air delivery pipe 41, which arrangement assures a positive feed of oil down through the pipe 37 and also assists in breaking up the oil into small particles at the sharp delivery point 38, thus improving combustion especially at high loads. The oil leaking out of the pump bearing at the point 27, as stated above, drops into a pipe 44 from the bottom of which a small coiled copper tubing 45 leads to the main oil delivery pipe line. 35 beyond the control valve 31, from whence the drip oil flows with the main oil supply to the combustion chamber. The small sized tubing 45 functions as a damper and prevents sloshing back and forth of the body of oil between the level in pipe 44 and the overflow delivery point 36. The various parts of the apparatus are so arranged that the drip point 27 is sufiiciently above the delivery point 36 to allow the pump leak oil .to go to that point by gravity even when the air pressure in the air delivery pipe 41 reaches its maximum. Note that the drip point is about on a level with the armature shaft of the motor 22; that is, at about the center of' theblower housing 48 (see Figs. 1 and 2).

The air delivery and control thereof is as follows The motor 22 has a shaft extension 46 on the end opposite from the oil pump 19 on which is mounted a centrifugal fan or blower wheel 47 which revolves in a blower housing 48 and which delivers air under low pressure to the air delivery pipe 41 leading to the combustion chamber 39. On the inlet side of the blower housing is mounted a plate 49. enclosing the blower wheel blades 51 and having a central air inlet opening 52, The device for controlling the an supply to' the blower, and consequently to the combustion 'chamber, consists of a stationary shutter having a stationary part 53 bolted to the intake side of the blower housing and a movable part 54 mounted for rotative movement on a bolt 55 passing through and-supported by the stationary part 53. A coiled compression spring 56 on the inner end of the bolt 55 acts through the latter movable shutter part 54 seated against the stationary part 53 so as to prevent leakage of air to the-blower inlet openin 52 through the contact surfaces of the two s utter parts. The stationary shutter part has two diametrically opposed

open quadrants

57 and 58 and intermediate

closed quadrants

59 and 61. The movable shutter part comprises diametrically opposed

closed quadrants

62 and 63 and intermediate open quadrants complemental to the

open quadrants

57 and 58 no t to hold the in thel'z stationary shutter part. The open A quadrants in the movable shutter part are graduated in size, com' rising

openings

64, 65 andiiltifl 68 and" 9-i'at'uthe o posits side and each is adapted to be close to a variable degree by a plate held in position on the shutter part '54, in this case byscrews 71, said plates be ng a. t .,,one side 0 the shutter and 67,

numbered 72 to 77 inclusive. When the movable shutter part 54 is in the closed position, that is, with ,the two quadrants containing the openings 64 to 69 inclusive opposite the

closed quadrants

59 and 61 of the stationary shutter part, no air may pass to the blower inlet opening 52 through the shutter. In this position the blower fan wheel merely revolves in the housing and delivers no air to the combustion chamber 39 except what reaches the blower housing through the opening for the fan wheel shaft and, in addition, through a series of small, low load inlet holes 78 in the stationary shutter part 53 which may be plugged or opened to allow the proper amount of air to enter for supporting combustion at low load. The amount of air admitted to the blower at different successive positions of the movable shutter part may be varied by the position of the res ective plates 72 to 77 inclusive. This ad ustment is made when installing or setting up the apparatus for the purpose of securing the desired amount of air in proportion to the fuel feed at the different loads, as will be presently explained.

It is one of the purposes of my invention to connect the air and oil controls so that they are dependent one on the other for operation and will consequently maintain a predetermined relative proportion between the air and oil feeds. The connection between the movable shutter 54, which controls the air delivery, and the oil control valve 31 comprises, in this instance, a link 79 pivotally connected at one end 81 to -a bracket arm 82 radially adjustable on the shutter part 5.4 by adjustment of screws 83, and at its opposite end 84 to the lever arm 34 abovementioned, on the stem 32 of the oil control valve. The lever arm is adjustably connected to the stem 32, in this instance by a set screw 30 which clamps againstthe periphery of a hand wheel 33 fixed to said stem. The oil feed at low load is determined by setting the control valve 31 (by adjustment of the set screw 30) when the movable shutter part 54 is in the closed position. By reason of the foregoing construction the air and oil feeds will be simultaneously opened and closed in predetfimined relative rela-' tion so that the proportions of the oil and air will be correspondingly controlled. According to my invention the air feed or delivery is variable at different loads to suit the conditions peculiar to each installation, in some of which greater or less amounts of air may be required at the intermediate or higher loads in proportion to the fuel feed, in order to assure complete and eliicient combustion at the different loads. This variable air feed is obtained by adjustment of the shutter parts for varying the size of the air inlet openings. It will now be observed that the-

shutter openings

64, 65 and 66 are located diametrically opposite from the

plates

75, 76 and 77 .respectively, and that the

openings

67, 68 and 69 are similarly located with respect to the

plates

72, 73 and 74. This arrangement is designed to permit adjusting the oil and air feeds at this first position are,

however, accurately determined to suit the draftand other conditions at hand, in the following manner: When the opening 64 is fully open and the opening 67 is just about to uncover part of the lower right open quadrant 58, a greater amount of air will be admitted through said opening 54 than is necessary for supporting proper combustion of the oil delivered at this'position. The plate 72 will then he slid over part of the opening 64 to cut down the air supply to the correct amount and will then be locked in such position by the screws 71. Similarly, a further movement of the shutter part 54 in the same direction will move the next succeednipulation of the wheel 33 on the oil control valve or the handle 85 on the movable shutter part; or,,in the event that automatic control is desired, a suitable thermostat regulator 86 is provided, in this case mounted on the frame 17 below the motor, blower,

etc., and connected to the movable shutter part by a link 87.

The combustion chamber per se and the method of burning the liquid fuel or hydrocarbon therefor, forms the subject matter of my companion application for Letters Patent, Serial No. 54,861, filed September 8, 1925, but will be described herein in order to convey a clear understanding of the present invention. This combustion chamber is designed to fulfill the requirements of a continuous flame burner which are discussed above, and its construction is an important factor to the present invention. The mixing or combustion chamber is, in its preferred embodiment, a casting, the shape of which is best shown in Figs. 7 8 and 9. The vertical air-delivery pipe 42 fits into the inlet end shoulder 89 of the combustion chamber casting which has an air inlet opening 91 rectangular in cross-section. The combustion chamber is defined by a vertical back wall 92, a vertical side wall 93 at right angles to the back wall; an opposed side wall which is curved in a vertical plane, as seen in- Fig. 9, and at an acute angle to the back wall in a horizontal plane, as seen in Fig. 7, a slanting bottom wall 95.making an acute angle with the back wall 92, as seen in Fig. 8, a low load pocket-96 extending out from the side wall 93 contiguous to the back wall, an outlet opening 97 which is preferably circular as shown, and a top wall forming a hood over the outlet opening. The combustion chamber is supported inan upright position by suitable legs 98 integral with the casting, which'rest on a base 99 which in turn rests on the furnace grates 101 over which a layer of fire brick 102 is placed for protection. The combustion chamber may, however, be supported in any suitable manner in a furnace or heater according to the particular installation.

The operation is as follows: The blower and pump, driven at a constant speed by the motor, w1ll deliver air and oil to the combustion chamber, as described above. The air and oil enter the interior of the combustion chamber through the opening 91. Oil drops by gravity from the delivery point 38 to the slanting bottom wall 95 and runs down to the lowest point of intersection of the bottom wall 95, back wall 92 and pocket 96, p or what I have termed the vaporizing. point 103. When initiallystarting the burner it is necessary to preheat the combustion chamber as by means of a gas torch, gas flame, oil

soaked waste, or the l1ke for vaporizing and igniting the oil. After the burner is thus started the heat from the combustion of the oil will maintain a temperature high enough to thereafter efl'ect vaporization of the oil and to produce a continuous flame, dependent of course, on continuous air and oil feed. The air jet coming thrcnlgh the inlet opening 91 passes down along the side wall 93, impinges against the slanting bottom wall 95, V and mixes with the vapor at said vaporizing point 103. Here the mixture splits into two parts, the smaller of which enters the pocket 96 where combustion begins with a spinning flame, thus supplying heat to the metal of the combustion chamber near said vaporizing point. At low loads the burning mixture in the pocket 96 constitutes a large percentage of the total combustion, in fact, the pocket functions as though it were a small auxiliary combustion chamber enabling a very low rate of oil consumption without the flame being blown out or without the metal 1 becoming too cold for vaporization, thus making a separate form of gas or electric pilot light ignition, or other li hting means of this sort, unnecessary. T e flame in pocket 96 emerges horizontally from the top half of the pocket and continues along that part of the back wall 92 at the rear of the pocket. This flame spins, as shown by the arrows, and joins the rest of the burning mixture along the lower part of the back wall 92. As the amounts of oil and air are increased, the proportion of the burning mixture in pocket 96 becomes less and less of the whole, but is always sufliciently large enough to supply heat to the metal at the vaporizing point 103, at which point at high loads a. small film of oil forms and spreads out along the intersection of back wall 92 with the bottom wall 95 and into the bottom of said pocket 96. Because the incoming air jet impinges'at an abrupt angle to the surface of the oil film, the carbon residue is burned up as fast as it is formed. The main portion of the mixture at higher-loads turns away from the pocket 96, along the bottom wall 95 and then up along the curved side wall 94. The burning mixture is thus caused to whirl or revolve in the combustion cham: ber, as indicated by the arrows, but is held back in the chamber to some degree by the inclined bottom wall 95 so as to prolon the vaporization period in the combustion 0 amrevolving or whirling burning mixture inthe combustion chamber but at the same time allow it a smooth escape through the outlet opening 97 which, it will be observed, is hooded at the top to throw the flame out horizontally and to keep it as low as possible in the combustionchamber of the' furnace. The shape and proportions of the combustion chamber 39 are such as to eliminate the formation of carbon deposit at any and all loads, to secure a thorough mixing of the fuel vapor and air, to g ve a clean white flame at all loads, and to reduce the noise usuall produced by the rapid combustion at big loads. The vertical mounting of the combustion chamber gives a horizontal flame to touch the cold boiler surfaces (in a the boiler. In boilers where the fluesare opposite the coal door, a fire brick baflle wall is placed a short distance in front of the combustion chamber to deflect the hot. gases and throw them out at the side and top so that they will impinge on these surfaces of the boiler.

A pipe 10 1 leads from the base 99 to a trip bucket 105 which actuates the safety valve 15 above-mentioned. In case of any failure of the flame, oil fills in the combustion chamber 39, runs out into the base 99 and partly fills the bucket 105 which then trips the valve 15, thereby shutting off the supply of oil to the furnace. The safety valve may also be actuated by overflow or leakage of oil into the drain pan 106 from which the oil flows through pipe 107 to the bucket 105.

In use, in order to minimize the change of the chimney draft producedby changes of outdoor conditions, the usual check draft door in the furnace is opened to an amount equal in area to three or four times the area of the then becomes so high in comparison to the chimney draft that the changes in outdoor atmospheric conditions have a negligible effect.

It is believed that the foregoing conveys a clear understanding of the objects prefaced above and, While I have illustrated but a single working embodiment, it should be understood that many changes might be made in details of construction and in the construction and arrangement of the several units and instrumentalities as may be required in different applications and for furnaces or heaters of different types Without, however, departing from the spirit and scope of the invention as expressed in the appended claims, in whichclaim:

1. Fuel burning apparatus comprising, in combination, a combustion chamber, a blower for delivering air, means for delivering fuel to said combustion chamber, a control valve for regulating the feed of fuel delivered by said means, an air inlet control for the blower comprising a plurality of separately adjustable shutter elements arranged to be adjusted one after another to secure a desired proportion of air to fuel at different loads, and means connecting said air inlet control and fuel feed control to maintain a determined relation between the amounts of air and fuel delivered to the combustion chamher at different loads.

' 2. Apparatus forburning gaseous or. vaporized 'fuel comprlsing, 1n combination, a

bustion chamber, a control valve for regulating the feed of fuel delivered by said means, an air inlet control shutter for the blower, means connecting said shutter and and oil into the combustion chamber, a con trol valve for the oil delivery feed, a control valve for the air delivery feed comprising a plurality of parts arranged for separate adjustment for different operating loads, and means connecting said valves to determine the relative proportions of air and oil delivered to the combustion chamber at the diflerent loads, the parts of the air control valve permitting independent adjustment of the air feed for every step by step adjustment of the oil feed.

4:. Apparatus for burning liquid fuel comprising, in combination, a combustion chamber, a constant speed motor, an air blower and a centrifugal oil pump constantly driven by said motor and connected to deliver air and oil into the combustion chamber, a control valve for the oil delivery feed a control valve for the air delivery feed comprising a shutter plate, means connecting said valve and plate to determine the relative proportio-ns of air and liquid fuel delivered to the combustion chamber at the difierent loads, and means comprising a plurality of separately adjustable shutter pieces on said plate, each being arranged to be set for a given operating load, for varying the amounts of air delivered to the combustion chamber with respect to the amounts of oil delivered there-.

air under pressure to a combustion chamber 1 including a shutter control for the air operated in synchronism with the fuel feed control, said shutter including variable openings for varying the amounts of air increase with respect to the fuel increase at different loads. I

6. A fuel burning apparatus, means for feeding fuel, and mechanism for delivering air under pressure to a combustion chamber including a shutter control for the air operated in synchronism with the fuel feed control, said shutter having variable air openings. f i

7 .,A fuel burning apparatus for producing a constant flame variable to'high and low loads comprising, 'in combination, a combustion chamber, a constant speed motor, an air blower driven thereby and a fuel line for delivering air and fuelto said combustion chamber, an air inlet shutter for the blower comprising, in effect, a plurality of air valves and a plurality of air openings controlled thereby, each valve being separately adjustable to suit a particular operating load, a control valve for the fuel, and a control connection between said shutter and valve for determining the proportions of air and fuel at the difierent operating loads.

8. A fuel burning apparatus for producing a constant flame variable to high and low loads comprising, in combination, a combustion chamber, a constant speed motor, an air blower driven thereby and a fuel line for delivering air and fuel to said combustion chamber, an air inlet shutter for the blower, a control valve for the fuel, and a control connection between said shutter and valve for determining the proportions of air and fuel at the different operating loads, including means for arying the air delivery with relation to the fuel feed at said different loads without affecting the proportion of air to fuel at other loads.

9. Fuel burning apparatus comprising, in combination, a combustion chamber having fuel delivery means therefor, and means for delivering air to said chamber including a blower for delivering air having a shutter comprising a stationary part and a movable part, the stationary part having diametrically opposed air inlet quadrants and the movable part having closed quadrants adapted to normally close said inlet quadrants and also having a plurality of air inlet openings and means for varying the size of said openings, said air inlet open ings being arranged to be moved in succes sion into registration with said air inlet quadrants by operation of the movable shutter part.

10. In a burner, in combination, a combustion chamber, and means for deliverin fuel and air to said chamber in determined relative proportions throughout the range of operation from low to high loads including several separately adjustable means for varying the relative proportions of air to fuel at low and high loads as well as at any intermediate load, the said means permitting an independent adjustment of the air p feed for every step by step adjustment of the fuel feed to insure the proper proportioning of the two for all loads within the range of operation.

11. In an oil burner, in combination, a

combustion chamber, and means for delivering oil and air to said chamber in determined relative proportions throughout the range of operation from low to high loads including several separately adjustable means for independently varying the relative proportions of air to oil at low and high loads as well as at any intermediate load, the said means permitting an independent adjustment of the air feed for every step by step adjustment of the oil feed to insure the proper proportioning of the two for all loads Within the range of operation.

12. In a' fuel burning apparatus, in combination, a-combustion chamber, and means for delivering air to said chamber in regulated volumes including an air control shutter having plural series of air inletopenings and an adjustable closure for each opening, said openings being arranged to open in succession, alternating from one series to another.

18. In a fuel burning apparatus, in combination, a combustion chamber, means for delivering fuel and air to said chamber in-- cluding a fuel control valve and a blower, the blower having an air inlet shutter, said shutter having plural series of air inlet openings and an adjustable closure for each opening, said openings being arranged to open in succession, alternating from one series to the other, and means whereby the fuel cont-rolevalve and air shutter will be operated to deliver determined proportions of fuel and air at various loads to the combustion chamber.

14. In a fuel burning apparatus, in combination, a combustion chamber, a valve for furnishing fuel to the combustion chamber means for delivering air to said chamber for supporting combustion including a blower having a shutter for controlling the air inlet, means for admitting air to the blower when the shutter is in the closed position for supporting combustion in said chamber when the fuel valve is in the low position, said shutter having plural series of air inlet openings and an adjustable closure for each opening, said openings being arranged to open in succession, alternately from one series to the other.

15. In combination with a furnace, an air control including a shutter having a rela tively fixed and a movable part, the latter being adjusted for proportioning the air supply with respect to the fuel supply, the fixed part being open for the admission of air, the movable part normally closing the opening in the fixed part and having lural series of air inlet openings and an adjustable closure for each opening, said openings being arranged to be moved in succession over the opening in the fixed part, the successive order alternating from one series to the other.

16. In combination, a combustion chamber, a valve controlled means for delivering air to said chamber for supporting combustion, said air valve comprising pivotally connected parts, one stationary and the other rotatable, the. stationary part having diametrically opposed air inlet quadrants and the rotatable part having diametrically opposed series of air inlet openings and an ad1ustable' plate for each opening, said air inlet opemngs being so locatedaas to suecess vely uncover the quadrant openings by I rotation of the movable part, the successive close to a variable degree its respective air nlet open ng so as to limit the air supply 111 proportion to the fuel at different loads. 10

In witness of the foregoing I afiix my signature.

order alternating from one series to the other, and each plate being adjustable to Patent No. 1, 654, 658.

JOHN H. MQILVAINE.

- CERTIFICATE OFYCORRECTION.

Granted January 3, 1928, to

JOHN H. McILVAINE.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 6, lines 59 and 60,

claim 2, strike out "Apparatus for burning gaseous or vaporizing fuel" and insert "Fuel burning apparatus"; page 6, .lines 110 and 119, claims --5 and 6, strike out the article "A" and insert instead "In a"; and that the said Letters Patent should be read with these corrections therein'that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 31st dayof January; A. D. 1928.

M. J. Moore,

Seal. Acting Commissioner-of Patents.

mafia may wnform tn the 5. Moore, Jissismer @f Patents" lw l Signed and sealed this day of Januaay, A

Seal.