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Publication numberUS3541190 A
Publication typeGrant
Publication dateNov 17, 1970
Filing dateOct 1, 1969
Priority dateOct 1, 1969
Publication numberUS 3541190 A, US 3541190A, US-A-3541190, US3541190 A, US3541190A
InventorsFlynn John H
Original AssigneeFlynn John H
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Gas-stream heating method
US 3541190 A
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Description  (OCR text may contain errors)

"Nov. 17, 1970 J; H. FLYNN GAS-STREAM HEATING mmnon Filed 001:. 1, 1969 John INVENTOR HEW/717 fiozwg/r United States Patent 3,541,190 GAS-STREAM HEATING METHOD John H. Flynn, 234 Elk Ave., New Rochelle, N.Y. 10804 Continuation-impart of application Ser. No. 759,741, Sept. 13, 1968, which is a continuation-in-part of application Ser. No. 559,246, June 21, 1966. This application Oct. 1, 1969, Ser. No. 868,960

Int. Cl. F231 7/00 US. Cl. 263-52 Claims ABSTRACT OF THE DISCLOSURE A burner installation located in a gaseous stream to be heated has a burner casing with a flame surface to which lead main and pilot flame ports for flames projecting downstream of the gaseous stream into a flame space therein. The installation further provides for operation of the burner, including shielding of the flames from extinction by partial vacuum induced by the passing stream, by constantly delivering to a pilot space part of the flame space a gaseous medium at a rate to suppress therein any stream-induced flame-extinguishing partial vacuum at any stream velocity.

This application is a continuation-in-part of my prior application Ser. No. 759,741, filed Sept. 13, 1968, now abandoned which was a continuation-in-part of my prior application Ser. No.v559,246, filed June 21, 1966, now Pat. No. 3,437,322.

This invention relates to a gas-stream heating method, and more particularly to a gas-stream heating method involving flame as the heating medium.

The type of gas burner used in the method with which the present invention is concerned is a gas-fed flame burner installed within a directed utility stream of air or other gas for heating the same, with the burner flame being directed down-stream of the passing stream. Such burners are used as heaters for all kinds of space heating especially, though not exclusively, in industrial establishments, and they are also used for other purposes such as heating large volumes of air or non-combustible gases in industrial processes, for example. It is among the more important requirements of these heaters that for a burner in any installation the heat of the burner flame must be able to flash the temperature of the passing air or gas to a high peak at maximum operational stream velocity. This requires, in turn, that the burner flame must maintain in the air or gas stream a zone of very high heat intensity. Another important requirement of these heaters is flexibility in operation over a wide range, to the end of heating passing air or gas to the same or different temperature peaks.

Among known flame burners that would best meet the aforementioned requirements of these heaters are those of high-capacity flame performance which are supplied with a quantitatively regulatable combustible mixture of preferably fixed air-gas ratio for sustaining the flames without any outside or secondary air and, hence, produce flames of high heat-output at widely regulatable flame velocity or drive independent of the velocity of the passing air or gas stream. However, in these high-capacity burners the main or operating flames are sustained by pilot flames without which the main flames would extinguish since the rate at which the combustible mixture is fed to the latter is usually greater than the rate of flame propagation, and it is for this reason that these burners are of no avail as air heaters since the air or gas passing the burners at most operational stream velocities creates at the flame side of the burners a notable vacuum in which no pilot flames can persist. Recourse has, therefore, been had to burners of modified construction and operation in which at the 3,541,190 Patented Nov. 17, 1970 more prevalent higher operational flame settings, the usual pilot flames are lacking, with the flame ports being then supplied with more or less pure gas and the combustion air therefor being largely secondary air diverted from the air stream to-be-heated into combusting admixture with the gas beyond the flame ports for maintenance of operating, flames. However, while these modified burners are generally satisfactory, they are lacking in a few, but important, respects. Thus, the drive of the flames is dependent upon, and hence limited by, the velocity of the diverted combustion air from the passing stream, so that the flames lack any appreciable drive are are massed in rather close proximity to the burners which thereby are unduly subjected to heat. Also, correct regulation of the gas admitted to these burners for complete combustion on admixture with the diverted combustion air from the passing stream at varying operating velocity of the latter involves rather intricate gas flow control. Further, these burners do not lend themselves to many applications involving eificient heating of gas streams that lack air or oxygen and, hence, are incapable of furnishing the combustion air for the burners without which the latter cannot perform.

It is the primary aim and object of the present invention to provide for successful operation of an air or gas heating flame burner so that the same has the aforementioned high-capacity flame performance in an air or any other gaseous stream, including a stream devoid of oxygen.

It is another object of the present invention to devise a method of successfully operating a high-capacity flame burner in an air or any other gaseous stream, which features effectively shielding from the vacuum effects of the passing air or gas stream those critical flame areas of the burner adjacent the flame ports where such vacuum effects would otherwise extinguish the pilot flames and even the main flames if the pilot flames were not extinguished, so that any velocity of the passing stream the pilot flames will remain undisturbed and sustain the main flames at any heat-output and drive as fully as though the surrounding air or gas were not moving. In thus achieving high-capacity flame performance of a burner in an air or gas stream, the flame will, on regulation for high heatoutput and drive, strike deep into the passing stream of any velocity and there maintain an extensive and highly heated zone which does not unduly heat the burner but in which the streaming air or gas will at even maximum velocity have some definite dwell and be in most intimate heat-exchange relation not only with the flame itself but also with its products of combustion.

Another object of the present invention is to achieve, in the aforementioned method of operating a high-capacity flame burner in an air or other gaseous stream, eflective shielding of the critical flame areas from the vacuum effects of the passing air or gas stream, by constantly delivering to a pilot space part of the flame space in the stream, within which the bases of the main flames are in igniting relation with the pilot flames, a gaseous medium at a rate to suppress in this pilot space part any stream induced flame-extinguishing partial vacuum at any stream velocity.

A further object of the present invention is to provide in the aforementioned method for supplying the pilot space part of the flame space in the stream with air or another gaseous medium preferably and advantageously by simply diverting the same from the stream into the pilot space part.

Further objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

In the accompanying drawings, in which certain modes 3 of carrying out the present invention are shown for illustrative purposes:

FIG. 1 is a side view of a flame burner operated in accordance with a method embodying the present invention;

FIG. 2 is a section through the burner as taken on the line 22 of FIG. 1;

FIG. 3 is a cross-section through a modified burner, and

FIG. 4 is a part end-elevational and part sectional view of another modified burner.

.Referring to the drawings, and more particularly to FIGS. 1 and 2 thereof, the reference numeral designates a flame burner for heating a stream of air or other non-combustible gaseous matter, hereinafter referred to as gaseous stream. The burner 10 is to this end suitably mounted, in this instance, within a duct 12 in which a gaseous stream flows in the direction of the arrows 14 past the burner in order to be heated by the burner flames F.

The burner 10 has a longitudinal burner casing 16 with an internal chamber 18 and main and pilot burner slots 20 and 22 which extend substantially over the length of the casing 16. The burner slots 20 and 22, which are provided in a flame surface 24 of the casing 16, are in communication with the chamber 18, with spaced restricted ducts 26 in the casing providing in this instance for communication between the chamber 18 and the pilot burner slots 22 (FIG. 2). Arranged in the burner slots 20 and 22 are burner ribbon assemblies 28 and 30 which define main and pilot flame ports 32 and 34, respectively. The casing chamber 18 is through a conduit 36 supplied with a combustible air-gas mixture which on ignition at the flame ports 32 and 34 sustains main or operating flames F and pilot flames p, respectively. The chamber 18, which is part-cylindrical about the burner axis x, is in this instance formed by a through-passage in the casing 16 which is closed at both ends by covers 38 that are mounted at 40 on end flanges 42 of the casing. The burner casing 16 is in this instance symmetrical about a plane P in which the burner axis x lies and which intersects the flame surface 24 midway of its width (FIG. 2).

The burner described so far may be entirely conventional, and the same may be operated for high-capacity flame performance at which the air-gas mixture supplied to the chamber 18 will sustain the main and pilot flames F and 1 without any outside or secondary combustion air. Customarily, air and gas are premixed at a given ratio in a usual premixer ,(not shown) and the mixture conducted to the chamber 18 at widely variable volumetric flow rates for sustaining burner flames of correspondingly variable velocities or drive. The air-gas ratio of the mixture is usually chosen for optimum heat-intensity of the flames, and the main flames F are at their maximum setting of particularly high velocity or drive and also forward projection, but they would extinguish without pilot flames p since the rate at which the combustible mixture is fed to the main flames is in normal burner operation greater than the rate of flame propagation. However, if the burner described so far were subjected in the duct 12 to a gaseous stream at even one of the lower operational velocities of the latter in most any space-heating or other installation, the vacuum created in the vicinity of the flame surface 24 of the burner by the passing air would extinguish the pilot flames p and, hence, also the main flames F, and if such vacuum would perchance not extinguish the pilot flames p it may well extinguish the main flames F by interrupting them at their base b. Accordingly, the burner described so far is of no avail for high-capacity flame performance in a gaseous stream of mostany operational velocity.

In accordance with one aspect of the invention, the present burner is by structurally simple and quite inexpensive conversion adapted for high-capacity flame performance in an air stream of most any, and even the highest, operational velocities. To this end, provision is made to shield the critical flame areas of the burner, i.e., the pilot flames p and bases b of the main flames F, from the inevitable vacuum produced by the passing gaseous stream. This is accomplished in a broader sense by providing the burner with a channel formation outwardly from the flame surface of the burner casing of which the sides of the channel flank the critical flame areas of the burner, and continuously delivering to this channel at the level of the flame surface secondary air or non-combustible gas at a volumetric flow rate at which it will prevent any flame-extinguishing vacuum formation at the critical flame areas by the passing gaseous stream to-be-heated without, however, having any adverse effect on the stability of the main and pilot flames at any setting thereof. More particularly, this channel formation is part of a secondary chamber 50 which is preferably defined by a separate hood 52 over the burner casing 16. The hood 52 has opposite end walls 54 and a peripheral wall 56. In the preferred form of the hood 52, its peripheral wall 56 has a part-cylindrical portion 58 and tangentionally continuing planar portions 60, of which the part-cylindrical wall portion 58 rests against, and is at 62 secured to, the end flanges 42 of the burner casing 16, while the planar wall portions 60 converge toward, and define with the end walls 54, an opening 64 in the secondary chamber 50 which is in line with the flame ports 32, 34 and outwardly spaced from the flame surface 24 of the burner casing. The end walls 54 of the hood 52 partly close the secondary chamber 50 at its opposite ends between the end flanges 42 of the burner casing 16 and the opening 64, while the end flanges 42 themselves close the remainder of the secondary chamber 50 at its ends (FIG. 2). The end walls 54 of the hood 52 are in this instance parts of plates 66 which are separate from the peripheral hood wall 56 and conveniently clamped between the end flanges 42 of the burner casing and the covers 38 thereon, and the separate end walls 54 are in this instance further secured at 68 to outward flanges 70 at the opposite ends of the peripheral hood wall 56.

The part of the secondary chamber 50 between the flame surface 24 and opening 64 is in the form of a channel 72 which is open to the remaining part 74 of the chamber 50 at both sides 76 and 78 of the flame surface 24 (FIG. 2). The depth of this channel part 72 of the secondary chamber 50 is in any event adequate to shield the critical flame areas of the burner directly from the passing gaseous stream to-be-heated, and this channel depth is preferably only several times the maximum height of the pilot flames p as roughly shown (FIG. 2), so that virtually the entire main flames beyond their base b project at most operational settings beyond the opening 64 of the secondary chamber 50 and directly into the passing gaseous stream to-be-heated.

The secondary air or non-combustible gas, which is to be flown through the channel part 72 of the secondary chamber 50 for preventing therein a flame-extinguishing vacuum formation by the passing gaseous stream to-beheated, is preferably and advantageously derived from the passing gaseous stream itself. To this end, the hood 52 is provided, preferably at the burner side opposite the flame surface 24, with a restricted slot 80 which extends over the longitudinal extent of the secondary chamber 50 and through which gas from the passing stream is admitted into the latter. The secondary chamber 50 serves as an expansion chamber in which the admitted gas undergoes considearble reduction in pressure and velocity, and whatever turbulence the gas may develop immediately on its admission into this expansion chamber will largely be quelled as it approaches the channel part 72 of this chamber. This makes for fairly smooth and moderate-velocity flow of the admitted gas into and through the channel part 72 of this chamber and out through the opening 64 into the passing gaseous stream, at which it will prevent at the,

critical flame areas of the burner any flame-extinguishing vacuum formation by the passing gaseous stream to-beheated without, however, adversely affecting the stability of the flames. In fact, in the preferred formation of the channel part 72 of this chamber by the converging planar wall portions 60 of the hood (FIG. 2), the flow of the admitted gas through this channel part is so smooth that it has been found advantageous to pass this flowing gas into even closer proximity to the pilot flames p and the base b of the main flames This is achieved in this instance by providing the converging wall portions 60 of the hood withbafiles 82 which extend over the length of the channel part 72 and divert the passing gas generally over the flame surface 24. The gas is thus flown toward the critical flame areas of the burner, and this is preferred in this specific or any other formation of the channel part 72, since the pilot flames then operate with particular assurance in a virtual non-vacuum zone under all conditions and, hence, support and keep ignited the main flames from minimum to maximum heat output. The baflles 82in this preferred channel construction are suitably secured by exemplary screws 84 to the converging hood walls 60. Also secured by some of the same screws 84 to the peripheral hood wall 56 are spacer brackets 86 of exemplary V- shape which rest against the burner casing 16 and afford the hood additional supoprt on the latter. Admission of the gas into the secondary chamber 50 through the slot 80 also makes for maximum cooling of the burner casing 16 and exit end 64 of the chamber by this gas.

The hood 52, and in this instance its peripheral wall 56, is preferably and advantageously formed in two identical complemental sections '88 and 90 which are provided with longitudinal flanges 92 that are kept spaced to define the described slot 80 for admission of the gas, with these flanges 92 having to this end interposed spacers 94 that are held in place by bolts 96 which additionally lock the mounted sections 88 and 90 to each other. Preferably, the peripheral hood wall 56 is with its converging planar wall parts 60 so disposed that the secondary chamber 50 is in cross-section also symmetrical about the plane of symmetry P of the burner casing 16 (FIG. 2), whereby the flow of gas to the channel part 72 is evenly divided on the opposite sides 76 and 78 of the flame surface 24. Further, the hood 52 is in cross-section of teardrop-like shape (FIG. 2) which offers comparatively little resistance to the passing gaseous stream to-be-heated, with the flowing gas being shortly after passing the hood opening 64 largely reformed into a smooth-flowing stream which does not adversely affect the stability of the main flames F at any, including their maximum, drive and, hence, projection from the hood opening 64, and is in intimate heat-exchange relation with the main flames as well as with their products of combustion over the high-intensity heat zone of formidable extent maintained by these flames.

Underlying the described structural conversion of the burner is a method of its operation which constitutes an important aspect of the present invention. The method involved here is that of operating in a gaseous stream a flame burner with main and pilot flames projecting downstream of the stream into a flame space therein, by feeding the main and pilot flames with a combustible air-gas mixture that requires no secondary air, at rates greater and smaller than their respective propagation rates, so that the pilot flames will sustain the main flames in a pilot space part of the flame space within which the bases of the main flames are in igniting relation with the pilot flames, and shielding the flames from extinction by partial vacuum induced by the passing gaseous stream, by constantly delivering to the pilot space part air or any other gas at a rate to suppress therein any stream-induced flame-extinguishing partial vacuum at any velocity of the gaseous stream. This method is clearly demonstrated in FIG. 2 in which the pilot and main flames p and F project downstream of the gaseous stream into a flame space therein which extends from the flame surface 24 and encompasses the pilot and main flames. The pilot flames will sustain the main flames over a pilot space part of the flame space within which the bases b of the main flames F are in igniting relation with the pilot flames p, with this pilot space part of the flame space being, in the stream direction, of the depth of the described channel 72. Further, the described air or any other gas is constantly delivered to the pilot space part of the flame space at a rate to suppress therein any stream-induced flame-extinguished partial vacuum at any velocity of the gaseous stream. An additional feature of the method lies therein that the air or any other gas delivered to the pilot space part of the flame space is diverted from the gaseous stream.

In a more specific sense, the method features shielding of the pilot space part of the flame space from thereover passing gaseous stream, and delivering the air or any other gas to this shielded pilot space part of the flame space, with this pilot space part being in the exemplary burner of FIG. 2 the flame area in the described channel 72. Further, the air or other gas is diverted from the gaseous stream in downstream direction to the shielded pilot space part of the flame space and is expanded in the latter. This is demonstrated in the exemplary burner in FIG. 2 where air or any other gas is at diverted from the gaseous stream in downstream direction and is expanded in the secondary chamber 50 including the channel thereof.

Reference is now had to FIG. 3 which shows a modified gas-stream heating flame burner 10a that differs from the described burner 10 of FIGS. 1 and 2 primarily by having a secondary chamber 5001 which is of smaller size and volume and also surrounds only part of the burner casing 16a. In this modified burner, the hood 52a may in most respects be constructed like the described hood 52, except that the part-cylindrical portion 58a of the peripheral hood wall 56a extends between the end flanges 42a of the burner casing 16a and bears against the side of the casing opposite the flame surface 24a thereof to divide the part 74'a of the secondary chamber 50a into non-communicating sections 100 and 102 which are, however, in communication with the channel part 72a of the secondary chamber at opposite sides of the flame surface 24a of the burner casing. The part-cylindrical portion 58a of the peripheral hood wall 56a has at its opposite ends leg formations 104 by which it is mounted on the end flanges 42a of the burner casing. Air or gas from the passing stream to-be-heated is admitted into the chamber sections 100 and 102 through longitudinal openings 106 which are formed in the peripheral hood wall 56a preferably by striking therefrom baflles 108 which direct gas from the passing stream into the openings 106 and, hence, into the secondary chamber 50a. Of course, the modified burner 10a is also operated according to the hereinbefore described method.

Reference is finally had to FIG. 4 which shows another modified gas-stream heating flame burner 10b that differs from the described burners 10 and 10a of FIGS. 2 and 3 in that the hood 52b does not extend completely around the burner casing 161;. Thus, in the present modified burner 10b, the complemental sections 88b and 90b of the hood 52b terminate at 110 and 112 and are there spaced from the adjacent burner casing 16b to form restricted openings 114 and 116 which are open to the downstreaming air or gas to-be-heated and admit a metered amount thereof into the secondary chamber 50b. Of course, this modified burner 10b is also operated according to the hereinbefore described method.

What is claimed is:

1. In a gas-stream heating method involving a flame burner with main and pilot flame ports for main and pilot flames projecting therefrom in one direction, the steps of flowing to and beyond said burner in said one direction any non-combustible gaseous stream including one devoid of oxygen, with the stream enveloping the burner on passing the same, supplying the main and pilot flame ports with a combustile air-gas mixture at rates greater and smaller than the propagation rates of the respective main and pilot flames thereat, with the air in the mixture being adequate for complete combustion of the mixture, and shielding the flames from extinction by the passing stream by constantly delivering to the pilot flames and nearby bases of the main flames a gaseous medium at a rate to suppress thereat any stream-induced flame-extinguishing partial vacuum at any stream velocity.

2. The steps in a gas-stream heating method as in claim 1, in which the gaseous medium delivered to the pilot flames and nearby bases of the main flames is diverted from the stream.

3. In a gas-stream heating method involving a flame burner with main and pilot flame ports for main and pilot flames projecting therefrom in one direction, the steps of flowing to and beyond said burner in said one direction any non-combustile gaseous stream including one devoid of oxygen, with the stream enveloping the burner on passing the same, supplying the main and pilot flame ports with a combustile air-gas mixture at rates greater and smaller than the propagation rates of the respective main and pilot flames thereat, with the air in the mixture being adequate for complete combustion of the mixture, shielding from the passing stream a pilot space which extends from said flame ports in said one direction and within which the pilot flames are in igniting erlation with the bases of the main flames, and continuously delivering to the shielded pilot space a gaseous medium at a rate to suppress therein any stream-induced flame-extinguishing partial vacuum at any stream velocity.

4. The steps in a gas-stream heating method as in claim 3, in which the gaseous medium is diverted from the stream to the shielded pilot space.

5. The steps in a gas-stream heating method as in claim 3, in which the gaseous medium is diverted from the stream in downstream direction to the shielded pilot space and is expanded in the latter.

References Cited UNITED STATES PATENTS 3,051,464 8/1962 Yeo et a1. 26319 3,178,161 4/1965 Yeo et a1. 26319 EDWARD G. FAVORS, Primary Examiner US. Cl. X.R. 26319

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3051464 *Oct 20, 1958Aug 28, 1962Maxon Premix Burner CompanyAir-heating gas burner
US3178161 *Mar 5, 1963Apr 13, 1965Maxon Premix Burner Company InAir heating gas burner
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4075358 *Dec 29, 1976Feb 21, 1978Ralston Purina CompanyProcess for reducing combustion product residues in products dried by a direct flame unit
US4549866 *May 8, 1984Oct 29, 1985Flynn Burner CorporationMethod and apparatus for applying heat to articles and materials
WO2007093676A1 *Feb 15, 2007Aug 23, 2007Asikkala KaiBurner and atomizer for the burner
Classifications
U.S. Classification432/29, 432/223
International ClassificationF23D14/48, F23D14/58
Cooperative ClassificationF23D14/586
European ClassificationF23D14/58F1