US1776048A - Oil burner - Google Patents

Description

L. F SPEAR Sept. 16. a 1930.

oiL BURNIER Filed Oct. 26, 1927 3 sheetswsheet l c wi-w: N

INVEN'TOR.

k/Afiz ATTORNEYS L. F. SPEAR se'm jls, 1930.

OIL BURNER Filed Oct. 26, 1927 3 Sheets-Sheet 2 IN VEN TOR.

A TTORNEYS.

\\ w\\ an? MN Y L. F. SPEAR Sept. 16, 1930.

OIL BURNER Filed Oct. 26, 1927 5 Sheets-Sheet 3 6 W w 4 m 'INVENTOR.

ATTORNEYS.

Patented fiept. 16, E

PATENT LEOLYN-E-SPEAR, or wEs TFrELn, ivrAssACHUsETTs, ASsIGNOR To GILBERT & BARKER MANUFACTURING COMPANY, or SPRINGFIELD, MASSACHUSETTS, A CORPORATION OIL BURNER Application filed'october 26, 1927. Serial No. 228,914.

This invention relates to improvements inof the mixture, oil and air, are separately in-.

troduced,the mixture of these constituents being effected in the retort without the aid of mechanical atomizing devices. In burners of this type, the oil is vaporized within v the retort and the oil vapor is picked up by and mixed with, an incoming stream of air. -The.

air flow is sometimes induced by natural draft but. preferably by a fan or blower which forces the air through the retort in order to secure a controlled draft, usually of relatively low pressure. Such burners, being dependent on vaporization of the oil, must be maintained hot enough at all times to effect the vaporizing function. \Vhile the burner might bev started andstopped and a separate ource of-heat employed for keeping the necessary parts of the burner hot during periods when the burner is not in operation, it is desired to avoid the complications which would be necessary if this plan of operation were followed. ,VVith the burner offthis invention, theplan adopted is to operate the burner continuously during the heating season at either high or low rates according to whether or not heat is required from the heating plant with which the burner is associated. The

unsafe and uncertain: and is apt to result in a smoky fire and to cause excessive deposits of soot in the retort and in the boiler. There fore, the fan is kept in operation during low fire as well as high fire. Thefan, however, preferably operates at the same rate on high and-low fire and, accordingly, unless means are provided to prevent, air in excess of requirements would be supplied to the low fire. The airtends to cool the retort and thus opposes the action of the flame, making it necessary to use a higher low fire or else suffer the disadvantages which ensue from excess air, such as excessive, carbon deposits and a smoky and'uncertain fire.

I The invention has for an object the utilization of exhaust gases or products of combustion from the fire box, or other convenient source, in a manner such asto solve the above stated problem.

More partic'ularly, the invention has for an object the provision of means which auto-' The heating effect of these gases is utilized i to aid the low fire in the workofmaintaining the necessary parts of the burner hot during low fire operation. in its work instead of opposing it, as does the air. lVhile the heating effect of the gases is the primary consideration, yet there is the added advantage. that the gases tend as is well known, to spread and diffuse the flame and prevent local overheating of the retort and associated parts. An exceedingly low rateof .oil consumption on low fire can be secured and at the same time the burner can be kept hot so that, when later shifted to high fire, the full stream of oil will be-readily vaporized and flooding of the retort will be avoided.

Another problem for which this invention offers a solution, relates to the vaporization of the oil,-mixing of the oil with the air and burning the mixture in a retort or firepot without serious dlillCUltiS due to carbon deposits.- Burners of this general type, as heretofore provided, have the disadvantage that carbon deposits are readily and rapidly formed. 'Also the action is not confined en-- tirely to the retort but extends to the boiler The gases aid the flameair directing means, all of which are of img p v r proved construction and specially des gned with the object in view of producing a good mixture of the constituents and delivering a cleansharp flame into the boiler, without causing carbon deposits to such an extent as to necessitate season.

The primary characteristics are that the oil is vaporized to a large extent while out of direct contact with the incoming air stream;

cleaning more than once each that this vapor is delivered to, picked up by, I

and mixed with the air stream before ignition occurs; that the burning stream of mixture is turned and returned, during its passage toward the outlet of the retort, to mix the leaner and richer portions of the stream;

that the flame,'as delivered from theoutlet, '1s substantiallyuniform and homogeneous except that itis encompassed by a protecting envelope of leaner mixture; and that the leaner portions of the stream only are allowed to contact with and traverse the walls of the retort, thereby protecting such walls from the richer portions of the stream which tend rapidly deposit soot and carbon} There are many details, which contribute to the accomplishment of the above objects and these, as" well asother objects, will 'appear in the following description and be pointed out in the.appei ided claims.

The invention will be disclosed with reference to the which-. A

Fig. 1 is atop plan view of an oil burner embodying my invention;

Fig.2 is an elevational View, drawn to a small scale and showing in conventional. form the manner in whlcn the burner is installed in a steam boiler; j I

. Fig. 3 isa side elevational view, partly in section (taken along the line .3 -3 of Fig. 1),

ofthe burner;

Fig. 4 is a fragmentary cross sectional view taken on the line H of Fig. 3 and illustrates the air damper, which is shown'in closed position rather than in the open position shown in Flg. 3;

Fig. 5 burner; v I p v Fig. 6 is a cross sectional view thereof taken on the line 66 of Fig. 1;

Fig. 7 is a sectional 'view of the solenoid operated oil valve;

Fig. 8 is a cross sectional view taken on the line 8-8 of Fig.6; and

Fig. 9is a'diagrammatical view illustrative of an electrical system for controlling the burner; Referring to these drawings; the burner accompanying 3 drawings, in,

'tinues horizontally.

'tion.

is a front elevational view of the includes a retort 10, which is adapted to bev inserted through the fire box opening'e of a boiler Z), or the like, and to lie partially within the fire box 0 thereof. This retort has a flame outlet 11, formed in its front wall near the upper part thereof, and an inlet 12 for air and/or products of combustion, the latter being taken from the fire box 0. The inlet 12 is. formed by an extension 13 of rectangular cross section which extends rearwardly fronr the back wall of the retortnear the upper part thereof. The retort 10 is provided with a marginalflange 14, which is adapted to abut the outer face of the usual hinged fire box door dand to be secured thereto, as by bolts 15. This door (Z is cut out to form an opening to receive the retort and, in addition,- a rectangular opening 16 which is located centrally and immediately above-thetop wall of the retort. This top wall is normally closed but is provided with a removablecover 17,

through which access. may be had to the interior thereof when desired. By'opening door (Z, i. e. swinging it on its hinges d, the I retort may be moved out of the .fire boxc and tire box door opening a so'that cover 17 may be removed. An eccentric 18, mounted on a.

stud'19, secured to the top wallof retort 10,

serves to hold cover-17 in place in an obvious manner.

Provisions are made for supplying air, together with products of combustion from fire box o, to retort 10, orfor supplying the 'ne-j' tort substantially entirely with the product of combustion. Such provisions. include fan which comprises a rotor 20 and a casing" 21. and an electric motor 22, to the shaft 23 of which the rotor 20 is attached, all as indicated in Fig. 5. The casing 21 has a peripheral discharge passage 24 (Figs. 3 and 5), formed by an extension 25 of the fan casing,

which passage initially extendsdownwardly and toward the retort and thereafter cono This extension 25, as it approaches the retort, spreads out laterally on opposite sides, as best shown in Fig. 1 at 26, and finally terminates with a box-like end 27 (Figs. 3 and 5) of rectangular cross see This end 27 fits over the described extension 13 of the retort and is suitably secured thereto, as by screws 28 (Figs. 3 and 4).

Thus, the discharge passage 24- of the fan is connected to the inlet 12 of retort 10.

It will be'noted that the retort, which in v I itself is supported from door (Z, serves to support the fan casing and that the latter is provided with a flange 29 (Fig. 5) to which the bed plate 30 of motor 22 is bolted. The fan and motor are not large or heavy'and ordinarily can be suitably supported in the manner described. Howevenif desired, an

auxiliary support may be hadby connecting casing 21 to boiler b by a chain 31 (indicated conventionally in Fig. 2 and shown in part in Fig. 3) which chain 1s, or may be, attached to an eyebolt 32, adjustably held by a wing nut 33 to a lug34 on casing 21.

The intake to fan casing 21 is formed by aseparate casing 35. This casing at one end and rests upon the member 27 with its open end directed toward andin closely adjacent relation with a wall of boiler b. The casing 35 also, to a limited extent, overlies and rests upon the casing 25 and is suitably secured thereto, as by a screw 40 (Fig. 1), which passes through a lug '41 on casing 35 and threadsintocasing 25. The other end of casing 35 terminates with a side opening which communicates with the fan casing 2 l'and is encompassed by a. circular flange 42, secured by screws 43 to one end of fan' casing 21. Located Within the end 37 andsecured, as indicated in Fig. 4, to the top wall of the end 27-is a member 44. Thelatter is bent to'form, in conjunction with said top wall, a tunnel 45' which communicates with and ,forms an extension of the opening 16 in the fire box door.

It will thus be seen that the fan has an inlet 46, through which atmospheric air, preheated to some extent by contact with the walls of boiler Z), enters and an inlet 45, through which'products of combustion from fire box 0 enter. It is to be noted that this burner is not supplied with air from the ash pit, as is frequently customary,-'the grate usually being suitably covered-to prevent air from entering the fire box from below. It is also to be noted that an opening 47 (Fig. 5) is provided'in that end wall of casing 21 which lies adjacent motor 22. Some such opening is, of course, necessary at this point to permit entrance of shaft 23 into the fan casing and to provide necessary'clearance for the shaft. Accordingly, some air will enter the fan atthis point and this arrangement has the advantage that such air tends to prevent the transmission of heat from-the fan casing to the motor. Also, since the air cools these parts, it follows that the air which enters the fan is to some extent preheated.-

The oil is supplied to the retort by gravity flow from any suitable source. In Fig. 2 I have indicated in conventional form a tank 48, of relatively small capacity, which is secured to the wall at a suitable level above that of theburner. Oil may be supplied to tank 48 manually orautomatically by any suitable means and many expedients for this purpose are known to those skilled. in the art. Tank 48 is equipped with a discharge pipe 49, which terminates adjacent to the burner and is connected thereto by a flexible pipe 50, so as to permit freedom of movement of the burner,

taining a solenoid 56 (see Fig. 7), having a plunger 57 which reciprocates in a brass tube 58. This tube, which isconneeted to casing 54, has a closed upper end and-functions to prevent leakage of oil from the valve easing into the solenoid or associated parts. The plunger 57 at its lower end is provided with a needle valve 59, adapted to control the flow of oil from pipe 53 to a pipe 60, which is connected with the outlet of .valve oasipg 54. An adj ustable stop 6l,'th'readed through the lower end of casing 54, isladapted to. be engaged by the lower end of needle valve 59 to limit its downward movement. This stop is customarily set so as to prevent valve 59 from completely closing and so that only a very small opening is left to permit a relatively small flow of oil frompipe 53 to pipe 60. The stop 6l'is therefore the adjustment for low fire. "When solenoid 56 is energized, valve .7

59 is lifted toallow alarge flow of'oil through casing 54. The regulation of such flow, for high fire is however. controlled by other means.

The stop 61 is normally concealed and protected by a cap 62 threaded onto the lowerend of casing 54. The solenoid casing 55 is connected, as indicated in Fig. 5, toa casing 63 which in turn is supported by and below bed plate 30. Casing 63 is adapted to contain electrical equipment which is used in connection with solenoid 56, such as a relay.

and transformer.

The pipe 60, as best shown in' Figs. 1 and 5, connects the solenoid-operated. valve to a safety shut off valve contained in acasing 64. This valve is a standardcommercial article adapted to close on flooding of the burner. The valve has an operating stem 65 (Fig. 5) to which is fixed a weight arm 66 and a lever 67. A bucket 68 is suspended by a link 69 from lever 67 and is adapted to receive oil overflowing from retort 10, which oil is delivered to the bucket by a pipe 70. The bucket is enclosed by a two part housing 71, the upper portion of which is secured, as indicated, to valve casing 64 and provided with an opening to receive pipe 70. The bucket,- when filled to a certain degree with 'oil, will turn shaft 65 in a clockwise direction and cause the safety valve to completely close. The weight arm 66 has a lug 66' which abuts a stop 72 on casing 64 and when positioned as shown, holds the valve fully open. A

shield 73, secured to casing 64, is provided.

as a. partial housing for parts 66 and G7.

' The safety shut off valve is connected driver.

fire. A cap 78, threaded onto casing 75,.cov-

ers and conceals the part by which valve 76 ..is adjusted. Valve casing is open at its upper end sothat oil can flow up and into the interior of a sylphon-be-llows 79, 'WlllCll is. attached to casing 75 and serves as a closure for the otherwise open end thereof.

Oil passing through the outlet 7 7 enters a pipe which leads into the retort 10. As shown, pipe 80 enters through the bottom wall of extension v13 and is connected to a special elbow fitting 81, which isdisposed in passage 12 centrally between the side walls,

thereof. A suitable gasket 82 encompasses pipe 81 and is clamped between the bottom wall of extension 13 and the base of the elbow fitting 81,the latter being secured to said wall by screws 83 (Fig. 1). A screw 84, passing througlrthe top wall of OXtQllSlOll 13, threads into elbow 81 and aids in preventing with an interiorly threaded hollow hub 85 (Fig. 3) which is adapted for connection to a combmed vaporizing, distributing and baffle member.

The member, just referred to, is best; shown in Figs. 3 and 6 and conveniently takes the form of a casting 86. which is supported from elbow 81. The casting extends substantially all theway across the retort from oue side wall to the other,.except for small clearance -spaces 87, andalso extends from a position closely adjacent the t-opwall. of the retort -downwardly,forming a balllc by means of which the air entering throughpassage 12 1s,

for the most part, forced to pass downwardly toward the bottom and rearpar t of the re.- tort and inunder; the lower edge. of the baflle throughthe space 88.' The upper edge of member 86 is held from contact with the top wall of the retort by lugs'89, leaving apassage 90, thr'ough which a-part of the air stream may passalong and traverse the en-' 'tire top wall of the retort,- thcreby tending "to keep such wall and the coverl? cool but more'particularly serving for a more important purpose, later to be described. I

In the upper and front part of member a pipe 741 to a valve casing 75 which contains 1,?7'a,o4s

from the bottom wall of the pocket upwardly V 7 Thus, the lower part of. pocket 91 forms a trough buttermina-tes. short of the top wall.

93 and the upper edge 9 10f wall 92 forms a weir-over which oil may overflow from the trough. 2 The wall 92, at its central part, is

connected to the top wall of the pocket by a Web 95 and on each side of this web, the

upper edge of wall 92 is recessed, as at 96,

so that the weir is sli htly lower at the center than at the ends. Ti that more oil will fiowdownwardly in the center than at the sides ofthe retort'and this. is desirable because the air stream is densor at the center than at the sides due to the is arrangement insures fanning out, as at 26,}ofthe discharge tube 25 of the fan. Also, in case the edge 94 is not exactly level, oilwill still flow over the eeri ter of the weir rather than wholly at one end, as would be the case if. the weir were of uniform height throughout'its length. A certain degree of leeway is afforded so that close accuracy in levelling the weiris not required.

The member 86 is secured'to the hollow hub 85 by a cap screw 97 which passes ce l- .it fromtilti'ng. The elbow' .81 terminates trally through'the front wall of pocket 91 through the pocket, and through. the central web 95, and threads into the hub. The head of screw 97 is drawn tightly against the front wall of pocket 9-1 and the end face of hub' 85 is drawn against the web 95. The'vscrew 97 is provided with anaxial passage 98 leading from its'threaded end inwardly toward but terminating short of the head. One or more radial passages 99, provided in screw 97, intersect passage 98 and afford communication between passage 98 and the interior of pocket 91, whereby oil may enter the latter.

v It is desired to shield the pocket 91 from the direct action of the air stream so that, so] far as possible air is kept from entering thepocket. The entry of air to such pocket, and:

the mixing of it with the oil therein, is not de- 5 sired bec ause it would then'be' possible for combustion to take place within the pocket.

Combustion within the pocket is not desired because it would result in the formation of coke] and tardeposits, which would soon fill 86 is formed a pocket 91' which extends'across from one side to the other of the member.

This pocket is entirely closed'at its front,

ends, top and bottom but.is only partially closed at the rear by a wall 92 which extends up'and choke the oil trough To this end,

the top and side walls of pocket 91 are ex:

tendedrearwardly, as at 100 and 101, respectively, and a plate 102,(l1ig.- 8) is secured by screws 103 to the extension 100. The walls 100, 101 and plate 102 form a box-like shield 'for the pocket 91. A horizontal ledgelOl', formed on the rear face. of. the back wall 92 extends toward; plate 102 but terminates short of the same, leaving an outlet passage 105, commensurate in length with the length of trough 93. The hub 85 0f elbow8l passes.

through plate 103, and a circumferential flange 106 (Fig. provided on the hub, lies closely adjacent the plate and makes it difii 10 will pass out through a pipe 70 (Figs. 1

and 3) which connects with the described overflow pipe 70 through the intermediary of asuitable trap or liquid seal, indicated at 70 .The casing 25, in one of itsflaring sides 26 is provided with an opening 107 (Fig. 1), which is normally closed by a cover 108. By opening this cover, one can insert a lighter through theopening for the purpose of initially igniting the oil, thus avoiding the necessity of opening door d and removing cover 17. 7

Means are provided for shutting off sub-.

stantially all of the air supply during those periods when the burner is operating on low fire. Such means comprises a damper 109 (Figs. 3 and 4) mounted on a shaft 110 which I in turn is mounted at its ends in the upstanding walls of member 37. This damper'is cut away, as shown at 111 so as to clear the tunnel 45, whereby when closed as shown in Fig. 4, the air inlet 46 is entirely closedwhile the tunnel remains entirely open at all times. This damper is made to open and close at proper times automatically and any suitable mechanismmay be used for this purpose. As

- shown herein, by way of illustrative example,'the damper is operated by the change in pressure of the 'oil when the valve 59 is moved from ,low fire to high fire position and vice versa For example,the damper may be connectedby a link 112 to one arm .of a bellcrank lever 113, pivotally mounted on ,a'stud 114, which is secured to a post 115 Fig. 5), the latter being secured to casing 35 by a screw 116. The casing 35, at a point adjacent the fan, has a depending tubular part 117 which is axially alin'ed with the bellows 79, heretofore described, and-a'link 118,.

" pivotally connected to the other and relati ely short arm .of bellcranlt 113, extends down-- ,wardly through the opening in part 117. The lower end of link 118 is adjustably connected, as indicated in Fig. 3, to a bracket 119 secured to the upper andclosed end of bellows 79. The latter is enclosed by acylindrical housing 120, secured at its lower end to valve casing 75. Housing 120, is connected to the tubular part 117 by a sleeve 121, which is secured to said part for convenient detachment, as by a screw 122 (Fig. 5). By

detaching screw 122, the sleeve 121 will slide down on casing 120 and expose the connection between parts 118 and 119, therebyallowing access thereto as well as to the upper end of bellows 79. An inwardly turned, circumferential flange 123 is formed on the upper end of casing 120 and a conical spring 124 acts between this flange and the top of bellows 79, tending ,to force the latter downwardly and close damper 109. In Fig. 4, it is as.

the pressure of the oil in bellows 79 materially drops and s ring 124 then functions to collapse the beli'ows and close the damper. Thus, when the burner operates on low fire, damper109 is closed and when it operates on high fire it is open. Also, the arrangement is such that a shift from one condition to another automatically operates the damper. It is to be noted that the damper is either open or closed andnever remains in any intermediate position. Also, that the movement of the damper from one position to another is rapid, being controlled by and caused to move substantially in unison with, the solenoid-operated oil valve.

Theparticular manner of controlling the operation of the oil burner is not an important part of this invention. Moreover, the burner may be used with various control and safety devices known in the trade. However, an example of one suitablescheme of control is shown schematically in Fig. 9. The fan motor 22 is connected directly to the line wires 126, which may be the usual commercial lighting or power circuit. The fan 21 is intended to run continuously during the heating season, wherefore the motor 22 is not provided with any control except for a manually operable switch, such as 127. The solenoid 56, by means of which the flow of oil to the burner is controlled, is' also connected to the line wires 126'but through the intermediary of a switch 128, which is adapted to be operatedby an electromagnet 129. The latter is included in series with two thermostatically operated switches 130 and 131 in a low voltage circuit 132, supplied by a transformer, the primary and secondary windings of which are designated 133 and 134, respectively. The winding 133 is connected to the line'wires 126. The thermostat to open when such temperature becomes ex- The control mechanism actually cessive. 'used is rather more elaborate than that shown in Fig. 9 but it functions in the same general manner as above set forth, and the conventional illustration has been adopted on the score of simplicity.

The burner, as has been set forth, is intended to operate continuously during the heating season. Consequently, it hardly necessary to provide an ignition means as on the few occasions when the burner has to be lighted, it may be accomplished manually. It is, however, obvious that any suitable automatic ignition means may be applied to the burner should it prove necessary or desirable. In lighting the burner manually, a torch of asbestos soaked with oil may be used, being inserted through opening 107 into the retort 10 and in close proximityto the rear face I of baffle 86. Previous to the insertion of the causing motor 22 to stop and allowing valve 59. to close down to minimum flow position. Damper 109, which opened when valve 59 was opened, also closed when that valve is moved to low fire position. Having sup.- plied the retort with'suflicient oilv for starting, by the above described .or any other suitable method', the torch is applied, as described, to ignite the oilinretort 10 while the valve 59 and damper 109 are in low fire position; The oil burns by natural draft, sufficient air entering through hole 107. The oil burns off the baffle plate 86 and in the retort and the heat therefrom, as well as that from the torch, heats thebaifle 86 and the walls of trough 93. Eventually, usually in.

less than a minute, oil will be vaporized in the trough and emitted from outlet 105, where it is ignited. As soon as vapor is thus emitted and ignited, the lighting torch is withdrawn, cover 108 applied and switch 127 again closed, thereby starting the fan in operation and opening solenoid 'valve 59' and damper.109. The burner is then operated under high fire conditions until the retort and the baflle member are thoroughly L now be described. 'Oil is delivered to trough heated, after which the burner will be allowed to continue in automatic operation (so long as switch 127 is left closed), running at either'high or low fire as controlled by the thermostat switches or either of them.

The normal operation, of the burner will 93 and air to inlet passage 12 at relatively low pressure. For example, the oil pressure may be a matter of ounces and the air pressure a fraction ofan ounce. Assuming that the thermostat switches are closed, valve 59 will be positioned to allow a full flow of oil and damper 109 will be open. F.an 20 is always in operationand at constant speed. Air, preheated tov some extent by contact with the boiler, entersat-- 46 and mingles v with a stream of productsof combustion entering at 45 whereby the air is further pre: heated by'thc heat exchange between the two constituents of the stream drawn into the fan. The fan serves to mix these constituents and thus air, diluted to a'certain prede termined degree with the products of combustion, is delivered to inlet 12: of the retort. The entering airand gases are hot and and the vapor is emitted at outlet passage 35 v 105. Some oil will also flow overweir 94; and such oil clings to the walls, following down, thefront edge of ledge 104, inwardly along its bottom face and thence downwardly along,

and following the contour of, the. baiiie 86.

Such oil, as thus flows onto the baffle, while distributed across the bafiie, is in greatest volume near the central'part thereof, where the air stream is densest, as has been explained- The baflle, being hot, the oil flow- 95 ing downwardly on the rear face thereof is vaporized and ordinarily allvaporized before it reaches the lower edge of the baifie. That is, under normal conditions, and so far as can be seen, no oil drips from the bottom v edge of baflie 86. If oil does drip from such edge, then it will be picked'up by and carried alongwith the stream passing below such edge. No deposit of carbon is found on the bottom of the retort below the lower edge of theba'flle aswould be the case if unvaporized oil lodged there and burned. It should be noted that the fan maybe speeded up and the oil flow increased if the burner is required to furnish more heat. When the burner is thus operated more oil will overflow from trough 91 and flow down on bafile 86. Then oil does drip 'fronrthe lower edge of the baffle but it is picked up by and carried along with the stream as aforesaid. The air and gases, entering at 12, are for the most part caused to pass downwardly and to sweep past outlet passage 105 and to pass along the rear face of baflle 86, thereby picking up the oil vapor and mixing with the same. The region in back of baffie 81 and down to about the level indicated by the dotdash line 00 is one in which preliminary mixing takes place, during high fire operation.

Ignition occurs at about the region indicated 12 by the line :1: although the. parts of the flame may be seen to flicker back and forth between this line and outlet 105 due to the burning ofi the baffle 86 of unvaporized oil.- .The streamof mixture passing down in back of 139 plate 86 will be found richest adjacent the plate and relatively lean adjacent the back wall of the retort. Also the mixture adjacent the sides of the retort is lean since less oil is emitted at the sides thanin the center. Thus, the sides and back of the retort are traversed by the leaner portionsof the mixture and in this way kept relatively free from carbon deposits. As the now burning. stream turns at right angles to pass in under the lower edge tof the bafiie, further mixing may take place here, especially on high speed operation when the stream'picks up-oil dripping from the Power edgeof the baffie and carries the same forwardly. The stream passing along the b, tt-om wall of the retort is nevertheless lean ,ilithat portion which moves adjacent to such by ll, whereby the latter is kept relatively free of, carbon deposits. So also, when the stream strikes the lower and semi-circular part of the front wall or nose of the retort, the lean portion ofthe stream lies adjacent to the retort wall. This nose is extremely hot and any unvaporized oil carried forwardly by the stream.will burnbefore it leaves the-nose. The leaner part of the stream, being now well heated aids in the burning of oil which reaches the nose and also in burning off and I preventing, accumulations of carbon. The stream is turned by the semi-circular wall, thrown back toward the front face of'baffie 86, and caused to roll around in the retort\ to a certain extent tomix the lean and rich parts of the stream, which is finally thrown forwardly toward and then downwardly out of the outlet 11 A substantially homogeneous mixture is obtained at this outlet except for the edges of the stream which are still somewhat leaner than the mixture in the body of the stream. The strear. of air-and gases, unmixed with oil vapor, passingthrough passage and across the topwall of retort 10, serves to keep said wall somewhat cooler and to prevent the formation of carbon deposits thereon. Such lastnamed stream functions like an air curtain for the described purpose and-also'supplies additional air to the flame for-combustion. The stream, as emitted from outlet 11, is in the form of a rich mixture surrounded by an envelope of leaner mixture. The flame emitted is clean and sharp, due to the thorough mixing, and is not ofsuch a I nature as tobe particularly liable to deposit.

sootin and dirty. up the boiler. Frequent cleaning of the retort and boiler is therefore not necessary.

All walls of the retort 10 are traversed by the leaner portions of the stream, as abovedescribed, and the purposesof this arrangement is to prevent carbon deposits in the retort. Carbon will form on both faces of baflfle 86. Such carbon as forms on the front face of the bafile has been found to be more of a sooty nature than of the hard coke-like variety. Coke-like deposits would have'to be scraped off but the sooty deposit, after accumulating to a certain extent fallsolf in flakes and is picked up by the stream and burned. On the rear face of the baffle, deposits of a tar like nature will fOIIIl'. The lighter fractions of the oil will be distilled off leaving the heavy constituents on-the plate. These deposits burn offto some extent during low fire operation. No carbon is ordinarily formed in the pocket 91 nor'in trough 93 during high fire operation for no burning takes place therein. The idea is to confine the carbon deposits to the baflle which is easily removable for cleaning. j

Assuming now that thermostat switch 130 opens, the solenoid 56 will be deenergized and valve 59 will drop to restrict the flow of oil. The pressure of oil on bellows .79 is then relaxed and. damper 109 closes under the influence of spring 124. The fan, however, con- -tinues to run at the same speed but now delivers to the retort products of"combustion. That is, for the most part, only gases from fire box 0 are supplied to the retort although, as has been explained, some air will leak in, as around the shaft 23. The cool air entering at this point is an advantage on low fire operation because since fan 20 draws almost entirely from fire box 0, the fan tends to become very hot and it is desirable to minimize the transmission of this heat to the motor 22. The'provision for supplying the retort, so far as is feasible, entirely with gases from fire box 0 during low fire operation is extremely important because of the material heating effect on the retort and battle member.

The gases aid very greatly in keeping these parts hot and inreadiness to quickly vaporize oil, when-the valve 59 is later opened to high fire position. Less oil needs to-be burned on low fire to maintain the retort and associated parts at the desired temperature and, of

course, this makes. for economy in oil consumption.

as it might not be commercially feasible ifa relatively heavier consumption of oil on low re were necessary because the low fire per ods are ldle ones in the sense that heat is not then when the valve 59 is shifted from high to low fire position, the trough 93 which was fullof oil when the valve shifted, becomes gradually depleted by vaporization. Finally,

oil which on low fire is fed virtually only drop.

by drop, can be heard to drop on the bottom.

Also, it makes it practical 'to operate on the high-low fire principle, where- .110

of the trough and sizzle on the bottom wallwhich is still hot. Oil vapor only is now.

emitted at 105 and this vapor, as before,

mixes with the incoming gases but burns near' the outlet 105. The flame then plays directly on the bafile plate and keeps it hot andburns off carbon formed on the rear face thereof during high'fire operation. .Theshiftingback, on lowfire, ofthe point'of ignition is important because, ifignition took place on low fire at the same point that it does on highfire, there would be little heating of thefbaffle plate and less heating of the wallsofthe oil trough. After the trough has been depleted of oil, it becomes somewhat cooler. and the vaporization of oil is retarded. Consequent- 1y, oil begins to accumulate in the trough so that a supply will be available when the burner is later shifted to high fire.

This accumulation of oil is-also important as preventing theformation of carbon wh1ch might otherwise occur if the drop by drop feed of oil to the warm bottom wall of the trough were'continued. That is, a little pile or mound of carbon would in time build up in under the outlet of the oil pipe. As the burner normally operates, carbon autumn-- lates only in the trough and on the baflle86. The carbon on the front face of the latter for V the most part falls off and is burned,,as abovedescribed. The carbon deposits in trough-93 and on the front face of the'vbafile are slow in forming and usually cleaning is required only once each season. The mounting of the baflie is such thatit maybe removed for cleaning very readily'. It is simply necessary to swing the burner out of the fire box, remove cover 17,- and remove cap screw 97 after which the baffle member may be withdrawn.- By then removingthe plate 102, access may be had to the trough for cleaning,

The idea of mixing products of combustion' with the air supplied to an oil burner is, of

\ course, well known; and it is known that this expedient tends to reduce the noise ofthe burner .and, by diluting the air stream, to retard combustion and .difi'us'e'the flame. In

the present burner, I make use of this expedient for the usual reasons on high fire operation. That is, during operation of the burner ona full flow of oil, a certain volume of products'of combustion is mixed with a certain volume'of air and the proportions of the two constituents are maintalned constant.

While deriving the usual and known ad-' vantages from the use of the products of combustion during full operation of the burner, I also make'use of them in a novel manner as an aid tothe solution of a special problem, which relates entirely to low fire operation. Having as a starting point a vaporizing burner of the fire pot type, without any mechanical atomizing of the oil, it is essential that certain parts in the fire pot or retort need to be kept hot enough for the vaporizing function. This means that the" burner must operate continuously, although at times at a reduced rate. IVith the stated type of burner, it is also essential to haven co ro led dra Th it s no safe to rely on natural draft even for low fire because *unless'the draft happens to be, just right, asmoky andsooty fire results. To operate a burner of this type on natural draft means that 'one is thrown entirely upon the mercy of the elements for the air supplyand the results are "at best uncertain and for the most part quite vunsatisfactory. I have found it necessary to maintain ahigh velocity stream in the retorton low aswell as high fire in enough'of a low fire is used, it means heavier consumption of oil during periods when no heating from the boiler is needed. Itis, of course, essential to keep the oil consumption on low fire as low as "possible and a com mercially satisfactory low rate cannotbe bad if air and gasesare supplied to thelow fire in the same way that they are to the high fire. The air would cool the retortand asso elated parts at a timefwhe'n it isessential to keep these parts hot with the lowest possible consumption of oil. The air, in eXcess,,Would not only prevent one from getting a good low fire but it also would .work a serious handicap by its eooling effect.

Therefore, I have provided the damper .109 which cuts off, so far as is practicahall air from the retort during low fire operation and causes the'fan to' supply hot gases thereto: These. gases enable a high velocity stream to b'e maintained through the retort without getti .g excess air. low oil flame in maintaining the vaporizing heat instead of opposing the action, as would theair, wherebythe oil consumption on'low fire may be cut down toa very low limit, say

drop by drop, in much the same manner that oil wouldflow from a lubricating oil cup. The gases also tend to diffusethe low flame,

The gases also aid the.

too

whereby it is spread over a greater area,

the fan and its intake and discharge tubes are kept hot so that whent'he burner is again shifted to high firefithere isno sudden inrush the better to maintain the parts Warm. Also,

of cold .air into the retort, v The full stream of air, admitted at such time, will bep're I discharge tubes and delivered in proper conheated by the hot fan casingand intake'aaid I i dition. Danger of flooding of"th e-retortat this time is thereby eliminated.

The damper 109 has no functionin-themorth -low fire conditio C u d be emitted i mal operation of-the burner and except for 75 order to avoid smoky, sooty flame. Therewould not be-bec'ause of the difliculty in maintaining a satisfactory low fire or, if this is accompished, a satisfactorily low rate of oil consumption on low fire. v

The invention affords a satisfactory burner of the vaporizing and fire pot type. The difficulties due to carbon deposits in the burner andthe tendency to cause dirty condition of the boiler have been overcome as well as the problem'of low fire operation. Also, there are no pilot or ignition complications or-difiiculties incident thereto. A very large'gerbentzige of the troubles developing in connection with oil burners have been due to diflicul'ties with ignition. By operating the burner continuously the ignition means and the ensuing troubles can be eliminated. The invention has been disclosed herein, in an embodiment at present preferred, for illustrative purposes but the scope of the invention is defined byvthe appended claims rather than by the foregoing description.

What I claim is: s 1: In an oil burner, a retort having an outlet adapted to communicate with a firebox and a passage for the admission of air to the retort, means for supplying oil to the retort at either a high or a low rate, a valve controlling the inflow of air to said passage, a connection through which combustionprodnets of the firebox may be delivered tothe re tort, and means for closing said valve and causing said retort to be supplied with prodnets of combustion when the oil supplyis changed from the high to the low rate. v

2. In an oil burner, a retort having an out- 7 let adapted to communicate with a firebox of'a boiler or the like and a passage for the admission of air to the retort, means for supplying oil to the retort including means for controlling the rate of flow and maintaining it at either a high or a low rate, a valve controlling the inflow of air-tosaid passage, a

connection through which products of the 1 firebox may be delivered to the retort, and

means automatically operable when-said con-- trolling means effects a change ,from high to low rate of flow for closing said valve and causing the retort to be supplied with the products of combustion.

3. In an oil burner, a retort having an out- I let adapted to communicate with a firebox of a boiler or the like and a passagefor the admeans automatically operable by the variation in oil pressure in said oil supply means when said controlling means effects a change from high to low rate of flow for closing said valve and causing the retort to be supplied with products of combustion.

4:. In an oil burner, a retort having an outlet adap-ted-to communicate with a firebox of a boiler or the like and an inlet passage communicating in part with the atmosphere and in part with the firebox for the purpose of receiving products of combustion therefrom, a valve for controlling the inflow of air to said inlet passage, connections for supplying oil to the retort, a valve movable fromone position in which it permits, a relatively small flow of oil to the retort to'another position in which it permits a larger flow of oil thereto for the normal fire, and means operable by variations in pressure of the oil in said oil supply connections for closing the let adapted to communicate with a firebox of a boiler or the like and an inlet passage communicating in' part with theatmosphere and in part with the firebox for the purpose. of receiving products of combustion therefrom, a valve for controlling the inflow of air to said inlet passage, connections for supplying oil to the retort, a valve movable from one position'in which itpe'rmits a relatively small flow of oil to the retort to another position in which it permits a larger flow of oil thereto for the normal fire, and means automatically operable by movement of the oil valve from the second to the first named position for closing said air valve and by movement of the oil valve from the first to the second position for opening said air valve. I

6. In an oil burner, a retort adapted to be mounted on the'door of a firebox of a boiler or the like and having an outlet to direct the flame into the firebox and an inlet extending through said door, a fan having a discharge conduit connected to said inlet and having anintake conduit extending toward and terminating with its air receiving end closely adjacent said door, said door having a passage therethrough for supplying gases from the firebox to said intake conduit, a valve to close off the inflow of air through said end, means for operating said fan continuously, oil supply means'including a valve which at all times permits a small flow of oil to the retort and is movableto permit a larger flow, automatic means for operating said oil valve, and means for closing said air valve when the oil valve is moved to cut down the flow of oil and for opening the air valve when the oil valve is moved to increase the flow.

7 In an oil burner, a retort having an outlet adapted to communicate with a firebox of m a boiler or the like and an inlet passage com-, municatingin part with the atmosphere and r in part with the firebox for the purpose of receiving products -of combustion therefrom,

' a valve for controlling the inflow of air to said inlet passage, connections for supplying oil to the retort, a valve movable from one positionin which it permits a relatively small flow of oil to the retort to another position in which it permits a larger flow of oil thereto for the normal fire, and means responsive to the rate of flow of oil for closing the air valve when the oil valve is in the first named posi- ,tion and opening the air valve when the oil valve is in the last named position. I

ing in substantially opposed relation an inlet passage for air' and an outlet passage forthe flame and being closed except for said passages,-means for delivering air to said in- 3 let passage, a bafile member in said retort opposing direct flow from the'inlet to the out- .let and serving to turn the major portion of the air stream and in conjunction with the walls of the retort to cause the stream to traa5 verse a tortuous path in order to reach said outlet, said baffle member having a pocket.

therein in which oil is vaporized while out of contact with the air-stream and a passage leading from the pocket through which un- 40 ignited oil vapor is delivered to the .entering air stream, and means for supplying oil to said pocket. 9. Anoil burner, comprising-a retort hav ing in substantially opposed relation an 'in- 5 let passage for air and an outlet passage for the flame and being closed except for said passages, means for delivering air to said inlet passage, a baflie member in said retort opposing direct flow from the inlet to the out i so let and serving'to turn the major portion of the air stream and in conjunction with the walls of the retort to. cause the stream to tra- 'verse a tortuous path in order to reach said outlet, said b aflle member having associated therewith an oil trough shielded from the incoming alr stream and an outlet passage for the vapors from the trough leading to.- wards that face of the battle which is engaged by'the incoming air stream, and means for to delivering oil into said trough.

10. An oil burner, comprising, a retort,

having in substantially opposed relation an inlet passage for air and an outlet passage for the flame and being closed except for said as passages, means for delivering air to said in- 8. An oil burner, comprising, a retort hav-.

let passage, a baflle member in said r'eto-rt opposlng dircc't flow from the inlet, to the outlet and serving to turn the major portion of the air stream and in conjunction with the walls of the retort to causethe stream to tra- "verse a tortuous path in order to reach said outlet, said baflle member having assoclated therewith an oil trough shielded from the incoming air stream and an outlet from the rear of the trough leading towards that face of the baffle which is en aged by the incoming L inlet and outlet for'the purpose of turning the air stream downwardly, said baffle extending. from the top wall of the retort downwardly towards but terminating short of the'bottom wall leaving a passage through which the stream passes toward thefront wall of the retort, said extending across the retort from one side wall to the other, the lower part of theffront wall of the retort being approxi- -mately semi-cylindrical to turn the stream back towards the battle and terminating with an upper edge defining one wall ofthe outlet,

,the' top wall .of the retort being projected forwardly beyond said edge and curved downwardly toturnthe stream thrown for Wardlybyuthe baflle toward the outlet, the lower edge of said downwardly curved wall defining the opposite wall of said retort.

12. In an oil burner, a retort having an inletfor air in the upper part of-its rear walland an outlet for the flame in the up-' per part of its front wall, a b aflle member supported within the retort and interposed between the inlet and outlet for the pur pose of turning the air stream downwardly,

said baffle extending from the top wall of the retort downwardly towards but terminating' short of' the bottom wall leaving a passage through which the stream passes towardthe front wall of the retort, said bafile extending across the retort from one side wall to the other, the upper edge of said baffle being spaced from the top wall of the'retort so as to leave a restricted passage through which a part-of the incoming air stream can pass directly from the inlet to-the outlet in a path adjacent the top wall'of the retort, the lower part of the front wall of the retort being approximately semi-cylindrical to turn the stream back towards the baffle andzterminating with an upper edge defining one wall of the outlet,

the top wallof the, retort-being projected forwardly beyond said edge and curved downwardly to turn the stream thrown forwardly by the baffle towards the outlet, the lower edge of said downwardly curved wall defining the opposite wall of said retort.

13. An oil burner, comprising, a retort having an inlet passage for air leading into the upper part of the retort near its back wall and an outlet passage for the flame leading from the upper part of the retort near its front wall, a battle member extending between the side walls of the retort and interposed between said passages to turn the air streamdownwardly, said baflie member depending fromthe top wall of the retort towards but terminating short of the V rearwardly bottom wall leaving a passage through which the down-turned stream can pass to reach the outlet, said baffle member constructed to afford a passage of restricted area through which air may pass directly from the inlet to the outlet, said bafile member having a pocket therein, means for supplying oil to said pocket, and means for supplying air to said inlet passage, said bafile having a passage leading from said pocket to the'rear face thereof arranged-to distribute oilcrosswise of the bafiie member.

14. An oil burner, comprising, a retort, having an inlet passage for air leading into the upper rear portion'of the retort and an outlet for the flameleadingfroml lfi PBPQr front portion of the retort, abafiie interposed between said passages and depending from the top wall toward but terminating short of the bottom wall of the retort, said baffle near its upper portion being hollow to form an oil trough which extends crosswise of the retort and is completely enclosed except along its rear side wall, a shield spaced rearwardly from the rear side wall of thetrough to direct the entering air stream from said trough and afi'ording betweenit and said rear side wall a downwardly directed outlet passage, and an oil supply pipe outlet passage, and an oil supplypipe connectcd to the battle to deliver oil into said trough, said rear side wall forming an oil distributing weir which is lower in the center than at the ends.

16. An oil burner, comprising, a retort having an inlet passage for air leading into the upper rear portion of the retort and an outlet for the flame leading from the upper front portion of the retort, a bafile interposed between said passages and depending from the top wall toward but terminating short of the bottom wall of the retort, said baflie near its upper part having an oil receiving chamber with an outlet therefrom to the rear face of the bafiie, an oil supply pipe terminating near the rear upper part of the retort with an end on which said battle is supported, a screw passing through the front face of the battle and across said chamber and threaded into the end of said pipe, said screw having a passage therein connecting said pipe and chamber, the upper wall of the retort having an openin therein through which access may be hacl to said screw and throughwhich the bafile may be removed, and a cover normally closing the last named opening.

In testimony whereof I have affixed my signature.

LEOLYN F. SPEAR.

connected to the battle to deliver oil into said trough, "said rear side wall forming a weir over which oil may overflow from thetrough and be distributed over the .rear face of said bafile.

15. An oil burner, comprising, a retort having an inlet passage for air leading into the upper rear portion of the retort and an outlet for the flame leading from the upper frontortion of the retort, a bafile interposed Eetween said passages and depending from the top wall toward but terminating short of the'bottom wall of the retort, said baflie near its upper portion being hollow to form an oil trough which extends crosswise of the retort and is completely enclosed except along its rear side wall, a-shield spaced from the rear side wall of the trough to direct the entering air stream from said trough and affording between it and

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