US2107800A - Carbureting ring structure for wall flame burners - Google Patents

Description

M. A. POWERS Feb. 1938.

CARBURETING RING STRUCTURE FOR WALL' FLAME BURNERS Filed Oct. 6, 1954 2 Sheets-Sheet l tion chamber.

mentioned, .having continuity,

Patented Feb. 8, 1938 1 UNITED STATES .PATENT OFFICE.

RING STRUCTURE FOR J WALL FLAME BURNERS Application October 6, 1934, Serial No. 741.220 f 9 Claims.

This invention relates to apparatus for burning liquid fuel in accordance with what has some to be known recently as the "wall flame principle. i

'This applicatlonis acontinuation-in-part of my co-pending application, Serial Number 729,- '928, flied June 9, 1934 for Fuel burning methods and apparatus; and is related to my earlier application, Serial Number 620,373, filed July 1st, 1932 for Ignition and combustion rings for 'liquidfuel burners.

The most "desirable type of apparatus for burning oilon the wall flame principle consists, as disclosed in said co-pending application, Serial Number 729,928, of a substantially horizontal hearth closing in the bottom of the combustion chamber, a central rotary head for distributing oil and air in distinctly separate layers toward the periphery of the hearth and a metal vaporizing and carbur'eting ring structure located adjacent the hearth periphery between the distributing head and the wall of the combus- A satisfactory ring structure for use in this combination is disclosed in my above- 'mentioned application, Serial Number 620,373, wherein a plurality of metal segments are mounted end to end upon the hearth to form the ring. In my other above-mentioned application, Serial'Number 729,928, it has been proposed to make up such a ring structure as a single piece having a continuous or unbroken surface substantially throughout its length by forming it as an endless structure or as a split ring having its ends in abutment. It is a primary objectoi the present invention to devise a new and improved, and particularly a simplified form of metal carbureting and vaporizing ring structure of the general type Just throughout its length. I

It is an object of my invention to provide a Flight metalliccombustion wall of special design for a liquid fuel burner of the wall flame type, and especially to devise and so arrange a metal vaporizing wall as to .promote maximum efliciency both in normaloperation and when starting andstopping the burner apparatus. I

It is a further major object of this invention to provide a simple channeled metal ring structure of endless formation in effect, whereby continuity is obtained substantially throughout its length. More specifically, it is an object to'devise a channeled metal ring structure comprising an outer imoerforate high wall for fuel im-' pingement and an inner low wall spaced from the substantially high wall to form an ignition gutter or chann therebetween.

- It is another object of the present invention to provide, adjacent the hearth periphery of a wall flame type burner, a chrome-steel ring formed of a simple upright horizontally curved band.

It is also an object of this invention to devise, for use adjacent the hearth periphery of a rotary wall flame oil burner, a metal vaporizing and carbureting structure that is simple to manufacture, easy to install and eiiicient in operation. '1

It is a further major object of my invention to devise new and useful means for mounting a carbureting structure upon the hearth of a combustion chamber between the fuel distributing means andthe surface to be heated. In this connection it-is a specific object of my invention to devise a mounting means especially adapted for use on ceramic hearths; and it is another object to devise a special mounting means for use on metallic hearths.

. It is a further important object of this invention to devise new and improved ignition means, and particularly, ignition means designed for use in connection with a metal fuel vaporizing wall. The foregoing and further objects of the in vention will fully appear upon a study of the fol- I lowing detailed description when taken inconjunction with the accompanying drawings and the appended claims. Y

Referring now to the drawings wherein like numerals are employed to designate like parts wherever they occur; 4 I

Figure 1 is a vertical sectional view taken substantially centrally through the combustion chamber and associated parts of one preferred form or apparatus embodying my-invention.

Figure 2 is a detailed view in perspective of one'of the ignition devices of Figure 1 and the mounting means used in connection therewith.

Figure 3 isv a view in perspective of one of the positioning assemblies utilized in Figure 1 to hold the ring structure upon thehearth.

Figure 4 is a fragmentary sectional view corresponding in general with Figure 1, but showing a modifled hearth construction for association :vith the vaporizing and carbureting ring strucure.

Figure 5 is a detailed view in section of one of the elements utilized in Figure 4 to secure the metal rings to the metal hearth.

The preferred burner system for incorporation in the invention consists of a distributor unit centrally located in a health, and which centrifugally throws oil and air in separate layers to the outer periphery of the hearth, with the combustion ring structure of this invention located adjacent said outer periphery; means for electrically igniting the oil, which is mixed with the air at the combustion ring; and grills for spreading the flame obtained. There are two forms of this general apparatus for embodiment of the invention. The first comprises a molded or ceramic hearth for use in boilersor furnaces originally designed for burning .coal or similar fuel; and the second comprises a metal hearth for use in furnaces which are originally designed for burning. oil.

The furnace of Figure 1 is of the converted coal burning type and comprises a boiler or water heater B, supported in the usual manner above the ash pit P. The latter also supports a hearth structure H which is built thereupon, and centrally of this hearth structure there is provided a supporting stand S carrying a rotary fuel and air distributing mechanism D driven by an electric motor M. Mounted upon the hearth adjacent to, but spaced inwardly from the periphery thereof, is a fuel vaporizing and carbureting ring structure R which is designed to support a plurality of flame controlling grills G. A pair of igniter assemblies I are disposed for cooperation with the ring structure and receive by mechanism associated with the latter.

Of the major parts of the apparatus above de scribed, onlythe ring structure R is claimed herein to be. new, and asthe present invention resides entirely therein and. in the mounting means therefor, but little attention need be devoted to the. structural detailsof the conventionifal parts of the apparatus.

The hearth structure H comprises a metal plategassemblyl 'I with ceramic material 8 of a refractory nature molded thereupon and around the 'upp e fipart of the supporting stand S to complteiy'close the bottom of the combustion chamber and to provide a substantially horizontal upper, surface. The rotary distributing head D is preferably constructed exactly as disclosed in my aforeementioned co-pending application, Se-

rial Number.729,9 28 and made in substantially the same form as that shown in my Patent No.

. 1,888,693. The chief requisites are that it receive oil and air internally of the supporting stand Sand discharge them without admixtureand in distinctly separate layers outwardly to ward the periphery of the hearth. For this purpose the rotary head has a plurality of fan blades 9 for projecting air in a concentrated layer directly across the hearth surface, and one or more fiinger tubes II) for throwing oil outwardly in the form of relatively large unatomized droplets directly abovethe' path of air flow.

The vaporizing and carbureting' ring structure ameter than that of the band l3 and it is of such height that when standing upon the hearth its :upper edge will preferably be at a higher level than the discharge ends of the flinger tubes III. In this manner the upper portion of the band l2 will be disposed in the path of the projected liquid fuel and it is for this reason .that this particular band is called a vaporizing ring. The band I3 is less than one-half as high as the band i2 and accordingly will not interfere with or intercept the fuel that is projected toward the upper portion of the band l2. The band l3 does, however, intercept the air that is supplied outwardly over the hearth to prevent the air blast from sweeping directly into the annular channel that is formed between the two bands. It causes some of the air to eddy downwardly into the channel, but directs the bulk of the projected blast toward the upper edge of the higher ring I2 to carburete the fuel that is vaporized by the latter and it is for this reason that the band I3 is called an air-deflecting ring.

The carbureting ring construction is maintained in the position illustrated in Figure 1 by molded portion 8 of the hearth. A substantially- U-shaped holding and positioning member l8 for the two rings is seated upon the mid-portion of the strip M. This U-shaped member has a relatively long upstanding leg l1 designed to cooperate with ring [2, and a relatively short upstanding leg I8 designed to cooperate with the ring I 3. This U-shaped member is anchored upon the strip I4 by a spot welding or like operation. A plurality of tabs l9 are struck upward- 1y from the sides of strip l4 so that the tabs engage the edges of the base of the U-shaped member as shown in Figure 3. Thetabs of each pair,

in the longitudinaldirection of the strip M, are

so spaced that their outer edges will abut against those surfaces of the two rings which face toward each other andthus prevent radial movement of the lower edges of the rings. Tabs [9 are intended to remain upright, but if desired they may be bent down againstthe upper surface of the U-shaped member. Member Hi preferably lies slightly below or flush with the hearth surface so that the lower edges of the rings may be slightly embedded in, or fit snugly directly upon the hearth surface, with the "result that the channel formed between the two rings will thus be effectively closed at its bottom. The

upper ends of the legs I! and I8 of the U-shapedplace, I preferably frictionally hold them in place by means of clampingextensions 20 and 22, so that the rings may freely expand'and contract in response to temperature changes without undergoing distortion. There are preferably a plurality of these positioning and holding assemblies.located about the periphery of the ring structure, but at two diametrically opposite points where the two igniter structures I are located, the positioning means will {preferably take a slightly different form, as illustrated in Figure 2.

With'further reference to Figure 2 the flat strip I40 corresponding with the strip l4 of Figure 3 is shortened at its inner end and has in lieu of an integral anchoring leg i5, a depend shaped insulator 25 which projects downwardly be set forth later.

through the hearth and which centrally carries an inner insulating member 26. The member 26 is in the form of a sleeve through which passes a metal conductor 21 that is connected at its lower end with the transformer T. The upper end of the conductor 21 has an electrode tip 28 and is so bent as to have a large air gap between it and all parts of the ring structure except Bracket 29 is spaced from the leg l1 sufiiciently to afford snug reception of the ring l2 between these two members and thus the bracket 29 takes the place of one set of the tabs IQ of Figure 3. The function and advantages of this firing plate will The flame controlling grills G are not essential to operation of the burner apparatus, but it is preferable to utilize them for the purpose of holding the flame down and concentrating heat at the lower part of the boiler leg. The grill-work may be formed of individual segments, each comprislng a perforated metal plate 32 constructed in the manner illustrated in the pending application of J. A. Wilson, Serial Number 682,374, and

with substantially U.-shaped brackets 33 welded to the bottoms of the :plates and .designed to be clipped upon the upper portionof the ring l2.

The perforated plates 32 are preferably so positioned as to overhang the annular gutter formed between the two rings [2 and I3, and to partially overhang'the annular space that is formed between'theavaporizing ring IZ-and the inner wall of the boiler.

v The ring holders and grills are all formed of metal and the metal used, particularly that for the ring, must have high thermal conductivity and also possess high resistance to deformation or destruction by heat. A satisfactory metal for this purpose is a steel embodying 16 to 18% chromium and a very low carbon content. Some nickel, as high as 8%, may be added. Due to difficulties encountered in shapingsuch a metal into complex structural formation without producing astructure that is weak or likely to cause later trouble, the illustrated simple construction is very desirable as it comprises merely two simple cylindrical bands and the other metal parts are of simple but effective construction. Each ring may be formed in an endless piece, or may be bent or rolled into the desired shape from a single straight strip of material, in which event its ends will be held close together during use. Theends of such a strip may be welded together, if desired, to obtain complete circular continuity of surface.

at all times.

Assuming that the furnace of Figure 1 is cold,

upon starting the motor the distributing head D will be rotated at about 1750 R. P. M. and oil will be thrown substantially radially outwardly by finger tubes ill in a trajectory that intersects the upper portion of the vaporizing ring l2. Simultaneously, a concentrated blast of air will be projected radially by the blades 9 along the hearth and when this blast reaches the ring l3 it will be deflected upwardly toward the top of the ring l2 while, as aforestated, some of the air will eddy into the groove formed between the two rings. As the ring I2 is cold, it will not produce any vaporization at this time. The oil impinging thereon will be shattered into smaller particles and part of it will fiow downwardly into the bottom of the ignition'gutter or groove formed between the two rings. During this starting period an ignition current is passing from the transformer to one a: the igniters, thence through the band or ring l2 and thence through the other igniter for return to the transformer. An intense fiaming arc is obtained between each terminal 28 and the corresponding firing plate 30, and these arcs will cause a flame to be produced above the surface of the oil collected in the gutter. The use of the firing plate 30, rather than allowing the spark to fire or arc directly against ring I2 insures that the gap will have a fixed clearance If the arc fired against ring 20, the gap would have to be adjusted at the time of installation. With the integral gap assembly no adjustment is required.

The thin metal rings and grills, having high conductivity without excessive heat capacity, rise in temperature very rapidly, and therefore in only a short time they are at normal operating temperature, permitting the ignition to be cut off. Under this normal heat, the projected oil is vaporized almost instantly as it spatters against the vaporizing ring i2 and at the top of the latter becomes perfectly carbureted with the air that is passed over the top of ring l3, Any oil that may on rare occasions, as the result of delayed ignition accumulate in the gutter, is rapidly consumed and this is also true of any oil that may get behind the vaporizing ring, as the latter is spaced sufilciently inwardly from the boiler wall to permit a part of the flame to wipe downwardly into the space adjacent the bottom of the boiler leg. As previously stated the flame is helddown and concentrated by the flame controlling and spreading grills G.

Figure 4 is incorporated to show my invention embodied in association with a boiler B2 and a base P2 that are specially designed for cooperation with a metallic hearth to burn liquid fuel. In this form the hearth structure H2 comprises a metal supporting plate 34 which is bolted to the upper part of the base at its periphery and designed to support the motor and distributor mechanism at its apertured center; a sheet of insulating material 35 arranged upon the plate 34; several U-shaped brackets 36 arranged upon the sheet of insulating material and a metal pan 31 or hearth proper which issupported by the brackets 36. This metal pan has a close fit at its apertured center with the head support S2 and is turned up at its periphery so that it will prevent the overflow of any small accumulations of oil. In like manner it has a close turned up fit with the ignition device I2 and and any other elements that'may project through the hearth.

In the form just described, the vaporizing and areidentically the same, both in structure and function as rings I2 and I3, rest in continuous circular contact with the hearthpan 31, and are i maintained in position with respect thereto by a series ofmetal angle members 38 each of which has a horizontal wing 39 adapted to be welded to the hearth pan and an upright wing 40 adapted to be welded to the ring. One of these ment bers is illustrated in detail in Figure 5.

In the form of invention just described, the flaming are from the ignition device passes directly from the electrode tip 28 to the vaporizing .ring I20. However, a firing plate may be utilized I if desired, similar to that shown in Figure 2. mv

all other respects the operation is precisely the same as that set forth for the apparatus of Figure 1. In some installations it may be desirable to utilize a special fan for use with the all metal hearth structure; and such a fan, for delivering a very thin concentrated stream of air along the hearth surface is disclosed in my afore-mentioned application, Serial Number 729,928.

Although I have illustrated rings l2 and I3 as being formed of strips bent into cylindrical. form, so as to conform to the shape of the combustion chamber of the particular boiler shown which is of cylindrical form in horizontal section, it is to be understood that where the boiler or furnace is rectangular or oval'in section, the rings may be bent to take the form of straight portions merging into curved portions or may be of oval shape so as to generally conform to the combustion chamber. It is to'be moreover understood that although the rings have each been disclosed as being constructed of a single piece of metal, they may, if' desired, be constructed in several pieces, overlapped in the region of the connectors,

so that they may slide back and forth in the frictional grip of the connectors in response to temperature changes, and the appended claims are intended to embrace my invention when it assumes this form. v

- Various other types of ignition assemblies and circuits may be utilized. For instance, that disclosed in prior Patent No. 1,890,862, and in my copending application, Serial Number 731,562, filed June th, 1934, may be readily incorporated in the vaporizing and carbureting ring structure of the present invention.

The invention may be embodied in other specific forms without departing from the spirit .or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a liquid fuel burning apparatus having a combustion chamber provided with 'a hearth and an upright wall, and means for projecting fuel toward said wall, an upright strip of refractory material disposed above'the hearth to intersect the path-of the projected fuel, and means for positioning said strip relative to the hearth, said means comprising a device secured to the hearth and having an upward extension providing a clip for reception of the upper edge of said strip.

2. In a liquid fuel burning apparatus having a combustion chamber provided with a hearth and an upright wall, and means for projecting fuel. toward said wall, an upright strip of refractory material disposed above the hearth to intersect the path of the projected fuel, and means mounted on the hearth for. positioning said strip relative to the hearth, said means comprising a horizontal metal member having a leg extending upwardly forengagement with that side of said strip which is adjacent the hearth wall, and another integral leg providing a metal firing plate expositioning said strip relative to the hearth, said.

means comprising a device secured to the hearth and provided with a leg extending upwardly for engagement with one side of said strip, and said device further having means spaced from said leg a distance substantially equal to the thickness of the stripand designed to engage the other side of the strip.

4. In' a liquid fuel-burning apparatus having a combustion chamber provided with a hearth and an upright wall, and means for projecting fuel and air toward said wall, an upright structure comprising a pair of concentrically spaced annular rings disposed above the hearth in the general path of fuel and air projection, and means for securing said structure to said hearth, said means comprising a substantially U-shaped memher having a horizontal part attached to the hearth and a pair of rigid legs extending upwardly from said horizontal part in close association with the respective rings, the upper end of each leg being shaped to grip theupper edge of a correspondingone of said rings.

5. In the combination defined in claim 4, said horizontal part being attached to the hearth by a plate that is directly secured to the hearth and that has tabs struck upwardly therefrom and bent into engagement with the upper surface of said horizontal partin proximity to the lower edges of said rings. f. f

6. In a device of thec f racter described adapted to be mounted as an assembled unit in a combustion chamber, a pair of upright refractory strips spaced apart laterally substantially in parallelism; a substantially U-shaped member having a bottom engaging corresponding edges of the strips and a pair of legs each engaging a certain side wall of one of the strips; and a substantially flat member engaging the bottom of the U-shaped said legs to maintain the strips in properly spaced relationship.

7. In the device defined in claim 6, said struck elements being bent over the bottom of said U- shaped member, andthe upper ends oi the latter being bent over the upper edges of the strips, whereby said strips are held against vertical separation relative to one another.

. 8. In a liquid fuel burning apparatus having a combustion chamber provided with a hearth and having an upright wall, and means for projecting fuel and air toward said wall, an upright structure comprising a pair of refractory strips spaced apart laterally and disposed above the hearth in the'general path of fuel and air projection, and means for mounting said structure on said hearth, said means comprising a substantially U-shaped member having a horizontalpart engaging the lower edges of the strips and a pair of integral legs extendingupwardlyadjacent the respective strips, sthe uppernend of each legbeing-shaped to receive and confine portion of the upper edge of thecorresponding strip.

9. In a liquid fuel burning apparatus, in combination with a combustion chamber having a hearth and an upright wall, with the hearth closing the bottom of said chamber in the vicinity of said wall, fuel distributing means for projecting a stream of liquid fuel above the hearth and toward said wall, means for projecting an air blast over the hearth below the fuel stream toward said Well, a thin cylindricaliy curved strip of metal set upright on said hearth in the path of fuel projection and spaced materially from said combustion chamber wall in the direction of said projecting means, and a similar strip of metal spaced from the first mentioned strip between the latter and the projecting means, said strips being sealed by the hearth and thereby forming a vertical channel between them that is closed at its bottom by the hearth, said second-named strip of metal being narrower than said first-named strip of metal for deflecting said air blast outwardly and upwardiy adjacent the upper edge of said firstnamed strip of metal, the latter being formed of comparatively thin sheet metal that has good heat conductivity but high resistance to destruction by heat.

MILTON A. POWERS.

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