US1747333A - Combustion apparatus - Google Patents

Description

Feb. 18, 1930. s. D. SUNDSTRAND 7 1 333 I I COMBUSTION APPARATUS Filed Feb. 25, l926 2 Sheets-Sheet l 2106mm C7127. fiundjtnmd, a; M mam Feb. 18, 1930. a. D. SUNDSTRAND 3 COMBUSTION APPARATUS 3 Filed Feb. 25, 1926 2 Sheets-Sheet 2 Patented Feb. 18, 1930 UNITED STATES PATENT OFFICE GUSTAF DAVID SUNDSTRAND, OF ROCKFORD, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO SUNDSTRAND ENGINEERING COMPANY, OF ROCKFORD, ILLINOIS, A COR- PORATION OF ILLINOIS COMBUSTION APPARATUS Application filed February 25, 1926. Serial N'o. 90,452.

This invention relates to a method of combustion and to combustion apparatus for oil burners and especially to apparatus havlng bowls or basins adapted for use in domestlc heaters, although the usefulness of the method and of such apparatus is not necessarily so limited.

In domestic heating some of the chief objections to the presentuse of oil burners is the noise attendant upon the supply of fuel and air during combustion, the production of odors, soot and smoke from inefiicient combustion, and the resultant increased cost of fuel on account of the low efficiency.

The present invention aims to provide a combustion bowl and a fuel nozzle so designed and so related, with due regard for the particular furnace, that the combustion is quiet, clean, complete and efficient.

Another object is to provide an arrangement which prevents localization of combustion; and which provides for a progressive combustion by a progressive association of the fuel with the oxygen of the mixed air and combustion products.

Another object of the invention is to provide a whirling flame so that the path of the gases through the furnace is relatively long whereby to permit slow, efficient and complete combustion in the fire box.

Other and ancillary objects and advantages will be found stated in the following description of the invention. In the accompanying drawings there are shown two specific embodiments of the invention given for the purpose of explaining the principles thereof and to show the manner in which the invention may be applied practically.

The form shown in Sheet 1 of the accompanying drawings is divisional from applicants copending application Serial N 0. 575,642 filed July 17, 1922, and the form shown on Sheet 2 is divisional from applicants copending application Serial N 0. 72,634, filed December 2, 1925, the latter form representing refinements in design and adjustments in the relation of the parts resulting from the intervening years of practical experience.

In the drawings, Figure 1 represents a plan view of the burner bowl and nozzle.

Fig. 2 represents a vertical cross section on the line 2-2 of Fig. 1.

Fig. 3 is a plan View of an alternative form of bowl.

Fig. 4 is a longitudinal section of the nozzle construction.

Fig. 5 is a side elevation of the improved bowl and nozzle, a fragmentary portion of the furnace being shown.

Fig. 6 is a view of the nozzle mounting on the front of the furnace, showing an adjustment feature.

Fig. 7 is a vertical cross section of the bowl taken on the line 77 of Fig. 8.

Fig. 8 is a plan view of the structure shown in Fig. 5.

It is to be understood that the devices of the drawings are subject to further modifications and to adjustments in the relations of the bOWls and nozzles. It is further to be understood that the invention is not hereby limited to the exact disclosures, but is to be defined and limited only by the scope of the appended claims.

Referring to the earlier embodiment of the invention, there is provided within the combustion chamber of the furnace a bowl 10 which rests on the grate bars 11 of a furnace indicated in part at 12 for the purpose of showing the general relationship to the furnace. In practice the firedoor of the furnace is removed and a special closure 13 (Fig. 2) is substituted therefor, said closure having an opening 14 through which the horizontal section 15 of an air conduit extends. To the inner end of the section 15 is secured an upright conduit section 16, the lower end of which is connected to the inlet 17 of the burner bowl 10. The bowl 10 which virtually constitutes a fire box, is of such size that it may be inserted into the furnace through the fire door opening covered by the special fire door 13;

and it is adapted to be set directly upon the grate of the furnace. If the grate of a given furnace be relatively low, a layer of suitable materialmay be placed between the grate and the bowl to support the latter at the proper height. It will be seen that it is unnecessary to remove the grate and to construct a fire box within the furnace, thus greatly lessening the expense for labor and materials in the installation of the apparatus.

As shown in the plan View entitled Fig. 1, the burner bowl 10 is circular and the inlet 17 is tangential thereto. The rim of the burner bowl is undercut to provide an annular concave internal wall 18 as indicated in Fig. 2, thus providing an internal annular lip 19 near the upper edge of the bowl. As shown in Fig. 2, the bowl is highest at a point adjacent to the inlet 17 and lowest at a point diametrically opposite such highest point.

Referring to Fig. 1, the dotted line 20 indicates the vertical plane of the axis of the inlet 17; the dotted line 21 designates a plane perpendicular to the plane 20; and the dotted line 22 denotes a plane approximately 15 away from the plane 21 in a direction remote from the intake 17. The highest point of the bowl is approximately at the point where the line 22 passes through the edge of the bowl nearest the inlet 17; and the diametrically opposite point where the line 22 pass-es through the edge of the bowl is the lowest point of the bowl. The rim of the bowl is tapered on both sides from the highest point and the lowest point.

I have found that a bowl twelve inches in diameter and with a single inlet 17 gives satisfactory results in ordinary installations. In installations requiring the production of a relatively large amount of heat, a larger bowl may be employed to advantage. Fig. 3 represents a bowl 1O which, in practice, may be approximately nineteen inches in diameter, and which has two diametrically opposite air inlets 17 and 17 The port 17 communicates with the pipe 16 through a passage 17 in the wall of the bowl.

Through the fire door closure 13 there extends a feed pipe 23 1). This pipeextends through an opening in the closure 13 and carries at its inner end, within the furnace, a nozzle 24 (Figs. 1 and 2) located on the bowl-side of the inlet. The nozzle is provided with a discharge orifice 25 arranged to direct fuel in the'form of a mixture of oil and air downwardly into the combustion bowl 10. It has been found that the point at which the combustible mixture strikes the bowl should bear a certain definite relation to the bowl and the inlet 17 in order that the best results may be obtained. When this combustible mixture is directed to the area marked 26 in Fig. 1, excellent results are obtained. If the mixture be directed to other points in the bowl smoke is produced or there is an increase in noise; or the flame is diminished or the even distribution of the flame around the bowl is affected; or there may be a space at the edge of the bowl where there will be no flame at all. It appears that the combustible mixture from the nozzle 24 should be directed into the air issuing from the inlet 17 at a point near said inlet in order to obtain the best results to eliminate the objectionable features just noted. There is further a very decided advantage in locating the nozzle 24 above the bowl 10 and directing the mixture down into the bowl as distinguished from locating the nozzle in the edge of the bowl, as, for example, in or near the inlet 17. hen the nozzle is located as last stated, the flame appears around the edge of the bowl but the central part of the bowl is dark; in other words, all of the combustion occurs near the periphery of the bowl and combustion is imperfect, soot accumulating upon the central portion of the bottom of the bowl; whereas when the nozzle 24 is located above the bowl so as to direct the mixture down into the bowl near the inlet 17, the bowl is completely filled with flame, there is no accumulation of carbon anywhere in the bowl, and the flame is whiter andmuchlarger, and rises from the center of the bowl as well as being spread outward from its edges. Moreover, the nozzle is in a position where it is relatively cool and therefore where oil will not carbonize on the nozzle.

On account of the whirling. movement of the air and combustible mixture within the bowl 10, the major part of the resulting flame would escape over the edge of the bowl at or near the place where the incoming air from the inlet 17 strikes the edge of the bowl were it not for the tapered formation of the wall of the bowl. lVith the tapered formation hereinbefore described, the flame is caused to circulate around the bowl and escape over the edge equally in all radial directions, so that even distribution of heat from all parts of the bowl is obtained.

The discharge orifice 25 of the nozzle 10 is preferably of relatively large size, as, for example, from one-eighth to three-sixteenths of an inch in diameter. In prior constructions where a relatively large discharge orifice was provided, a needle valve located adjacent to the discharge orifice was employed to regulate the discharge, thus greatly reducing the effective size of the discharge orifice and, in practice, so constricting the passage as to produce clogging when heavy oil was burned. It will be observed that in my construction no needle valve or the like is employed to restrict the discharge passage. As shown in Fig. 4, the end of the nozzle 24 opposite to the discharge orifice 25 has an opening 26 which is closed by means of a screw plug 27. The opening 26 is a necessary incident of the method of manufacturing the nozzle, but if for any reason the orifice 25 should become clogged the screw plug 27 may be removed and an implement inserted to clean the orifice. The nozzle merely provides for the emission and direction of fuel, preferably as a mixture of oil and air traveling under pressure through the conduit 23. Reference should be made to the above mentioned copending application for the details of the mixture and pressure producing apparatus, the character of which does not bear upon the present invention.

Any suitable means may be employed to ignite the combustion mixture, a gas flame being employed for that purpose in the pres ently described embodiment of my invention. A gas pipe 28 runs parallel to the feed pipe 23 and carries a pilot structure 29 which emits a flame at the opening 30. The pilot flame is directed downwardly so as to strike the jet of combustible mixture issuing from the nozzle 24, whereby said jet is ignited. It will be seen that the pilot light is located remote from the combustion bowl 10 and therefore will not be blown out by the current of air issuing from the inlet 17.

In practice when the apparatus is to be installed the workman inserts the combustion bowl 10 through the fire door opening and connects the conduit section 15 to the air supplying means (not shown). The

workman then provides a pipe 23 of proper length, screws-the nozzle 24 upon one end of said pipe, inserts that end into the furnace and screws the other end into suitable mixture supply means, the nozzle 24 being positioned so as to direct the jet of combustible mixture to the proper point within the combustion bowl. The workman then mounts the pilot light structure 29 upon the gas pipe 28. Connections having been made to sources of supply of fuel oil, gas and air, the apparatus is then ready for operation. The damper in the ash-pit door is preferably kept closed. Suitable means are utilized for adjusting the quantity of oil and air as described in the parent application Serial No. 575,642.

In the foregoing description of the earlier form, reference is made to certain features l which have been dispensed with in arriving at the improved and preferable embodiment of the invention. The improved form, however, maintains the same general relatlon of the parts and involves the same principles of construction and operation.

In the newer form a bowl is provided with an inner concave wall 36 and an inner annular lip 37 at the top of the bowl. A tangential air inlet 38 is provided which is in communication with an air supply conduit 39. The air conduit enters the furnace through the ash-pit opening 39 and is directed upwardly towards the bowl, the latter be ing located in the lower portion of the combustion chamber of the furnace. A vertical sleeve 40 is formed integrally with the conduit 39 to receive a supporting leg 41 for the bowl. A vertical web 42 is cast with the conduit and is integral with a peripherally flanged bottom plate 43 onto which the bowl casting is placed. The plate 43 has an elongated reservoir 44 formed therein into which is threaded a drain pipe 45 for removing oil therefrom. The pipe 45 is coupled with a pipe 46 leading to a suitable safety device (not shown). A hole 47 is formed in the bottom of the bowl to drain excess oil therefrom into the reservoir to be drained away for operation of the safety device in a well known manner. An inclined drip board 48 is cast with the bowl on the heater-front side and is so designed as to underlie the nozzle and to gather drippings therefrom, which, if they accumulate, will thus enter the oil reservoir 44.

The nozzle 50 in the present instance differs from the above described nozzle 24 in that it receives a separate supply of oil at 51 and of spraying air at 52, emitting, however, a spray mixture of oil and air as in the first instance. The nozzle is carried by a bracket member 53 which is rigid with a plate 54 pivotally mounted on a closure plate 55 secured to a fire doorway frame 56. The furnace is represented generally by the numeral 57 merely to show the relation of the parts to the furnace walls.

The pivotal plate 54 is shown clearly in Fig. 6 and is arranged to swing angularly in a vertical plane on plate 55 for the purpose of adjusting the angular direction of the spray, thus to cause it to impinge at the proper point in the bowl 35. The plate 54 swings about the axis of a sleeve 58 and is provided with arcuate slots 59 and clamping screws 60. The spray is directed along the line designated 61 to impinge upon the air entering the bowl in front of the inlet 38. A standard 62 aids in supporting the parts at the furnace door.

There is an electric ignition device associated with the improved form which is indicated generally at 63, having spark points 64 located in the path of the fuel issuing from the nozzle. mounted within the sleeve 58 wherein it is preferably made adjustable.

In the operation of apparatus embodying the present invention a controllable lowpressure large-volume supply of air is furnished to the bowl at the inlet. The air thus swirls around and is emitted both upwardly and radially from the bowl over the annular lip thereof.v The ignited oil spray is directed downwardly into the bowl at a considerable velocity to impinge upon the entering air near the inlet. The cone of the spray is, of course, somewhat elongated and displaced because of the moving air. Combustion, of course, takes place as the swirling gases circulate and rise. There being more oxygen near the bottom and greater heat and less oxygen at the top, the fuel is thus progressively introduced into the air supply,

The ignition device is thus ensuring perfect combustion. The spray passing through the hot rising and whirling gases readily becomes heated and in part vaporizes, such action taking place along the downward path of projection. This distributes the volatilizing area and contributes to the prevention of the roaring sound. The projection of the oil across the area over the bowl ensures that the above named advantages obtain. In the first form the oil is directed substantially across the whole area of the bowl while in the second form the oil is projected across substantially half of the area of the bowl. Each gives satisfactory results, however. The exact location of the nozzle in respect to latitude and as to height above the bowl is in part determined by the interior form of the fire box in which it is to be placed, as well as by the size of the installation.

The method of combustion employed in the two forms of apparatus above described is such as to minimize the noise and to increase the efficiency of combustion by impinging the oil spray upon a stream of air, the oil being directed ang ularly into the air stream and preferably somewhat in the same direction. The arrangement of the bowl or basin in which combustion takes place in part is such as to provide a long combustion path. The arrangement of the basin in the fire box of the furnace is so chosen that the gases of combustion are discharged from the fire box in a direction generally opposed to the direction of spraying the fuel. By this means there results the desired progressive association of the fuel with the oxygen, the fuel first passing through the combustion zone where it is partially consumed and preheated before admixture with the richest supply of oxygen.

Although I have shown the basin or bowl circular in shape for a domestic heater, it is to be understood that it may be elongated or otherwise changed for other heaters. In such cases the air is admitted into the bowl in accordance with the principles of the invention as hereinabove disclosed.

I claim as my invention:

1. A combustion apparatus adapted to be placed in a fire box of a furnace comprising a circular bowl having a large tangential inlet for a supply of low pressure air, an inwardly directed lip on the top of said bowl above said inlet, and a nozzle for spraying oil into the bowl, said nozzle being mounted above the bowl and being positioned to direct oil downwardly and laterally to impinge in the bowl on the air substantially in front of said inlet.

2. A combustion apparatus adapted to be placed in a fire box of a furnace comprising a circular bowl having a large tangential inlet for a supply of low pressure air and having a concave interior side wall, and a nozzle placed above the bowl and to the bowlside of the inlet, said nozzle being positioned to spray fuel into the bowl to impinge on the air substantially in front of the inlet.

3. A combustion apparatus adapted to be placed in a fire box of a furnace comprising a circular bowl having a large tangential inlet for a supply of low pressure air and having a concave interior side wall, and a nozzle placed above the bowl at the bowl-side of the inlet and outside of the circular opening of the bowl, said nozzle being positioned to spray fuel into the bowl to impinge on the air substantially in front of the inlet.

4. A combustion apparatus adapted to be placed inside a fire box of a furnace compris ing a bowl having an innerundercut side wall and an air inlet in the wall substantially tangential to the wall, and a nozzle adapted to spray fuel into the bowl substantially in front of the inlet, said nozzle being located above the bowl and on the bowl-side of the inlet.

5. A combustion apparatus adapted to be placed inside a fire box of a furnace comprising a bowl having an inner undercut side wall and a wall inlet substantially tangential to the wall, and a nozzle adapted to spray fuel into the bowl substantially in front of the inlet, said nozzle being located above the bowl and on the bowl-side of the inlet, and being located outside the opening of the bowl.

6. A burner bowl comprising, in combination, a circular bowl having an undercut inner side wall provided with a tangential air inlet, a draining reservoir beneath said bowl, there being a hole in the bottom ofthe bowl communicating with said reservoir, an upwardly extending drip board projecting outwardly from the top of said bowl, said board and inlet being substantially side by side whereby the bowl may be placed with the drip board under a nozzle and the nozzle may direct spray into the bowl substantially in front of the inlet, said board serving to direct drippings from the nozzle into the bowl for drainage into the reservoir.

7 The combination of a house-heating furnace having a combustion chamber provided with a fire doorway, said furnace also having an ash pit opening, a combustion bowl in, the lower portion of said combustion chamber, a conduit extending through the ash pit opening and directlv connected to said bowl for supplying a relatively large volume of lowpressure air to the bowl, a nozzle located adjacent to the fire doorway and at one side of and above the combustion bowl for spraying a mixture of oil and air down into said bowl, fuel-supplying means extending through said fire doorway and connected to said nozzle, and ignition means projecting through said fire doorway and located adjacent to and below the nozzle and in proximity to the spray discharged from the nozzle.

8. In an oil burning apparatus, a circular combustion bowl having a tangential air inlet, and means above said bowl for discharging a combustible mixture into the bowl at a point near the air inlet.

9. The combination of a house-heating furnace having a fire door opening and an ashpit door opening, abowl supported within the furnace, said bowl being small enough for introduction through one of said openings a 10 relatively large air supply conduit entering the furnace through the ashpit door opening and being connected to the bowl for delivering a large volume of low-pressure air horizontally into the bowl, and fuel-feeding means entering the furnace through the fire door opening and provided with a nozzle located relatively close to the fire door opening for discharging fuel downwardly into the bowl.

In testimony whereof, I have hereunto affixed my signature.

GUSTAF DAVID SUN DSTRAND.

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