US2600709A - Gas-burning torch - Google Patents

Description

June 17, 1952 R. M. VARLEY 2,600,709

' GAS-BURNING TORCH Filed April 20. 1941?; 2 SHEETS-SHEET 1 L R; 44 5 Q. 26

June 17, 1952 t VARLEY 2,600,709

GAS-BURNING TORCH Filed April 20, 1949 2 Sl'lEETS-SHEET 2 Roy M Var/ey Patented June 17, 1952 STATES r'rN-T OFFICE GAS-BURNIN G "TORCH Boy Varley, Dallas, Tex.

ApplicationApril 20, 1949,- Serial No. 38,667

I '2 Claims. (01. 158-99) a This-ei tention: elatsrtoin w a ,7 ,usef 111 movements;imgashurners.

, A- narticulari biect 20f th iinventioni so; pro- =v1de aa eimpmyedi as :burn r whi hw ipmciuc high fiame teznperaturesr withoutnequiring a supply oi aaizzunder pressure.

.i-A iurth iqbie taofathe invention i to p tvide aim improved; asiburnerL-which .will, op ra .iupon ..;either.nhigh p101; ,lO .pressure gas supplies an includesimeans for-- drawingtcomhustion :air into its interior andcthoroug-hly. admixing the ,isamei withi-zthe .icombustionrgas to,,provide a :.fiam ii relatively high temp ratu Y et-anothei:;Qbiectiof-...the inyention is to pro- ;vide aneimproyedggas-qburner constructed to emriployv. az1 hlgh.iyelocity jet,-, of, combustion gas and mcludin means-norm preventing an excessive drop 1- inpithet nllessuresotthe combustion gas, as it.passestthrou hathegburner.

A .iifurtheniohiect;10f -.=the invention is to pro- .:vi.de van: inmroved:gas:burner having aflrestricted gas jet and an impingement ring so spaced from ,thegjet and ,ofiigsuch; diameter with. relation to saidspacingethat a, -;co.ne .iOf gas ofgnormal proi-portions-yfiowing; from ,the Jet will barely ,im-

(.pinge-fiini a,.,peripheral' ijashion, upon said .impingement y -ring, whereby. thorough agitation a d. admixin of: air -.and- ;gas. upon the outer ,xportions ot isaidi. Leone ,is, efiected without ,the rec ea on;- fiundu turbulence in-ithe central por- 111191 1 thereof;

'Agparticularaobject oftthe invention is. to pro- ;yideean ;,improved ,gas {burner having ages :in-

let; jet a; plurality 0f Lgprimary air ,ports .sur-

' t ,jet 'and a pluralityi of secondary arranged ,in an annulus and spaced 811) the primary v airports directing r across edgesof the secondary air Qports n causing an aspiratingobair through e ondemsnor An irnportant object, of the; invention is to res t-the tr spo b i an e ti levationioi a ,hand torch. in-

stru ted -f 60 Flew h q h i iipe in f 3? t e-r a Fig. 21s a vertical, sectional view of the torch shown in Fig.1,

Eig. 311s a front elevation ofythe torch,

Fig. 4 'is' a rear elevation of [the torch,

Fig. 5 is a horizontal,'cross-sectionallviewof the handle ofthe torch, takenluponline 5+5 of Fig. 2,

Figs. 6, 7 and 8 are enlarged, vertioalrsectional viewstaken uponthe respective lines of Fig.2 .i

Fig. 9 is anenlarged view, partly in elevation and partly in :section of the burner.

Fig. 10"is agreatly enlarged, cross-sectional view taken uponthe. 1ine l0l0 of Fig. 9,

f Figs. 11. and-12 are fragmentarygsectional views taken upon the respective .IinesoffEigIQ, and I Fig. 13 is afragmentary View. in elevationpf the rearward portion of the burner unit.

in the drawings, the numeral 201'designates in general a hand .torchhaving incorporated therein a gas burner following the teachingsjo'f this invention. The torch includes a handle 2| formed of a suitable heat insulating material and having a gaseous fuel conduit 22 extending therethrough. A nipple 23 projects from the bottom end of e the, handle and isconnected to the conduit 22 for conducting the fuel gas there- .to. A rubber hose (not shown) or any other suitable fuel conductor. may thus be'connec'ted to the torch by the nipple23 forfsupplying fuel .gas thereto. .At the upper end oflthe handle, a pipe Ti l is secured to theupperend of'the conduit 22, vone branch 250f the T receiving the burner structure, andthenother'nreceiving a suitable plug 20 which may be removedffor access to the interior or bore of the burnerstructure should such an operation become desirable.

The burner structure includes a' burner unit, B and a finned conduit 0 leading'to the 'un'it'B. Theconduit C comprises a central pipe 21' having integral and closely spaced radial fins 28 formed on its outer surface. A screw-threaded pin 29 is provided at one end of'the conduit'C for reception in the branch 2'5 of the pipeTjl l, and a screw-threaded x30 at its opposite end for reception of the burner unit B. An'ihtegral cup?! surroundsithe box endof the conduit C and has an outside diameter substantially equal to the outside diameters of the, fins 28.1 [For shielding. thevfburner unit, anfelongate, thin walled sleeve 32 is pressed over the peripheryjof the cupv 3| and projects forwardly thereir'omfso as toenclo'se the rearward end of the burner unit. A'pluralityrof longitudinal airpasSage ,33'1'are .spaced,in an annulus about the conduitC and extend longitudinally through the bottom ofIthe cup 3: and t h the limit wi h theatres parallel to the longitudinal axis oflthe" central pipe 21.

Air y enter between the fin'sjfl. d

of the burner unit whereby an ample supply of air to the burner is insured, but at the same time, the latter is protected against drafts and currents of air which might affect its operation. In add he fins 28 function as heat radiating elements and as heat shields to prevent excessive quantities of heat from flowing from the burner unit to the handle structure to discommode the user of the torch. Because the fins receive heat from the burner unit, they, in addition, function as heat exchangers to preheat he inlet air and fuel gas, and to cause it to reach the burner unit in a thoroughly warmed or preheated condition. Some combustion air may also flow through the forward end of sleeve 3 and by reason of its passage over the outside of the burner unit, this air, in a similar fashion, is preheated before being mixed with the fuel as. It is further to be noted that the rearmost fin, spaced farthest from the burner unit, is imperforate to increase its heat-shielding action.

While the conduit C is important, the principal features of this invention are to be found in the burner unit proper, which is illustrated in detail in Figs. 9 through 13 of the drawings. The burner is applicable to many uses and may be employed both as a s o ary and a portable burner. Obviously, the burner may be made in a multitude of sizes and may be employed in a very small hand torch or in various intermediate sizes for portable and stationary heating, and in very large sizes for high capacity furnaces and the like. Therefore, the illustration of the use of the burner in a hand torch is to be viewed as solely for the sake of convenience and explanation, and not as creating any degree of limitation.

An enlarged view of the burner unit B, which may be readily detached from the conduit C by unscrewing from the box 30 of the latter, is shown in Fig. 9. The unit includes an elongate cylindrical housing 34 enclosing a mixing chamber D. The rearward end of the chamber is closed by a substantially transverse wall 35 from which a screw-threaded pin 36 projects rearwardly and axially. The pin 33 is adapted to be received within the box 33 when the burner unit is mounted or connected to the conduit C. An axial bore 31 extends through the pin 36 into the mixing chamber and has pressed therein a gas jet cup 38. A recess 39 is formed in the bottom of the cup 38 and extends within a few thousandths of an inch of the forward wall or outer wall of said cup bottom. Through this very thin section, which may as an example be apsandths of an inch, for instance 0.035 inch,

whereby an extremely small jet of fuel gas may be directed into the interior of the mixing chamber D. The cup 38 seats against an annular shoulder 4| which projects radially inwardly of the forward portion of the bore 31 and functions as a stop for said cup. Since the length of the cup is less than the length of th bore 31, it is obvious that the cup may be adJustably positioned within said bore in order to vary the spacing of the inlet orifice 40 from the rearward portion of the chamber D. As will appear more fully hereinafter, such adjustment sometimes necessary or desirable to improve the peration of the burner unit under certain conditions or with certain types of fuel supplies.

This burner unit is adapted to be used with 4 natural gas as commercially supplied, which may be furnished at pressures as low as 3 to 8 inches of water up to several pounds pressure. The burner is also intended for use with low pressure and high pressure gaseous fuels of the butane type, which may also be supplied at very low pressures or at pressures of considerable poundage. The construction of the inlet orifice 40 is of extreme importance in the case of the low pressure fuel supply. It is well known that the pressure drop created in a flowing fiuid, or in other words, the resistance to the flow of a fluid, is directly proportional to the length of the conductor through which it must pass. In the present instance, the orifice 40 is cut in a very thin wall, and the resistance offered by the side walls of the orifice to the flow of the fuel gas is practically negligible. There is the usual restriction loss, but the permanent pressure drop is small with the result that gas under pressure as'low as 3 to 4 inches of water supplied through the bore 31, are permitted to fiow through the orifice 40 in a relatively high speed jet with substantially no loss in velocity being caused by side wall friction within said orifice.

The stream or jet of fuel gas flowing from the orifice 40 into the mixing chamber D, behaves as' any high velocity jet or gas flowing into a large open space and tends to fan out into a cone. This cone approaches the side walls of the chamber D at a point spaced forwardly from the orifice 4i), and it has been found that such point of close approachment in the case of an unrestricted open jet, is spaced from the orifice a distance equal to approximately twice the diameter of the chamber D.

At this point, an annular impingement ring 42 is positioned. The preferable range of spacing of the ring or restriction from the orifice 40 may be stated to be from 1 /2 to 2 times the diameter of the chamber D. The ring 42 has a snug press fit with the interior of the chamber D and has its forward edge flush with the forward end of the cylinder 34, as shown in Fig. 9. As will be explained hereinafter, combustion air is flowing through the chamber D' with the jet of fuel gas, and the impingement of the combined flows of fluid upon the rearward edge of the ring 42 cre-' ates a marginal turbulence which results in thorough commingling of the combustion mixture. It is important that the ring 42 be of sufficient thickness to create adequate turbulence, and at the same time not be so thickas to unduly. impede the progress of the combustion mixture from the burner unit. A desirable ratio between the thickness of the ring 42 and its inside diameter has been found to be 1 to 8. However, it is manifest that a reasonable departure" from this ratio may be made without seriously impairing the operation of the burner unit, and the usable ratios may be stated as within the range from 1 to 4 up to 1 to 12. The inner or rearward face 43 of the impingement ring of course forms the in wardly directed, annular shoulder which provides a major portion oftheimpingement-surface. It is preferable that the outer margin of this shoulder surface be adjacentor forwardly beyond the point of intersection of the outer surface or margin of the conical stream of air and fuel gas with the inner surface of the mixing chamber D. If the impingement ring is too close to the orifice 40, there will be no impingement of the stream upon said ring and no turbulence will be created. On the other hand, if the ring is too far from the orifice, an agitation and turbulence air flowing through the. ring 42.

.ameter to equality with said diameter.

Another important feature of the burnerunit .t is the method and means of? applying air to form "the combustion mixture.

, effect will notibe' achieved, i..but'-rthe ;ring:;will merely function as: a. flow-impeding restriction member'in thetpath of the air-gas; mixture.

A combustion chamber .E is provided; beyond or forwardly of the ring 42, saidchamber being enclosed by an annular sleeve 44 having a press (fit over the forward end. ofthetsleeve 34. It has been found that actual ignition in the burnerunit takes. place-atqa point within thecchamber E placed a short distance forwardly of the forward ends or-,-edges:of the-sleeve 34;andthe,ring 42.

Thelsleeve 44 thus functions asa shield-to protect the point of ignition against air currents and drafts and thus functionsto keep-the burner ignited. The central portion of,the;,,cone; of, gas

jetted from the orifice4llalso functions as. a pilot light to maintain ignitionsincesuch-central portion passes unimpeded, through the; ring 42, ;-is not subjected-to turbulence-within the saidring, and has itsvelocityunreduced by said-ring. Of,

course, the shield or sleeve 44 also functions to focus or direct the flame produced, and for this reason, it is desirable. that its inside diameter be kept low-so that the stream of fuel gas and air does not undergo excessive enlargement upon exit-from the ring 42. It is preferable that-the inside diameter of the. sleeve 44 not be more than 50 percent greater than the inside diameter the combustion mixture.

The'ring 42 likewise hasan additional function and beneficial result in' preventing back firing of the flame to the fuel gas orifice40.

Since they streamis restricted withinthe sleeve 42, its velocity is increased. The proportions; of the ring are thus prescribed. The ring must have a boresmall-enough: to maintain the 31 6- locity of flow of the combustion mixture in excess of the rate of flame propagation for the fuel gmixture-being used; the longitudinal length of the ring must be sufficient to maintainthe increased velocity overa distance adequate to isolate the combustion and the ignitiomchambersf and, inopposition; both the contraction or restriction set up by the ring and its length must be held to a minimum ,to maintain the velocity of the entire gas and air stream. The prefer-, --a'blerange of width ofthe ring shoulder has been set forth hereinabove. and the preferable range for the length-of the ring has been found to be from one-quarter of the mixing chamber .di-

A 'plurality of primary air lnlet'ports'45 are arrangedin an annulus in the wall 35 so as to be in surroundin relation;v with respect to the orifice 40.1and so as. to have their axes roughly in parallelism with the axis of said orifice. vAs shown-intFig..9, the wall 35 is somewhat concave-convex in cross-section,-,and

her. The structure of the wall 35 is not of 1111-;v

.ifo'rward ofthe, primary ports .45. .Asshown in ."Eigs. 10 ,and.,13, the ports 46 are. somewhat, larger- .;.por tance; butthedirection or facingof the'openings 45 :is. ."jfBESldGS having -t the inward inclinavtion, :each of .thelopenings also have a. lateral component inzitsdirectional facing as illustrated in Fig; .10. :The axes .ofthe opening or ports 45 maythus be described as .beingtangent to tan imaginary-sphere or circle: of finite diameterlo- .cated upon the axis of the chamberDand-spaced plurality: of air. streamsiflowing. from the pluprecisely to tangentialintersection. Rather; the

limitation should; be impingement at an angle between tangential intersection and intersection in aplane normal to 'the'gas cone surface. "The :purposeof. thisarrangement is to effect arwhirllilg action. whereby the air'streams and the jet of fuelrgas flow in a helix :and are thoroughly commin'gled and 1 mixed I for combustion purposes. In practice,- this helical path is of constantlyen- .vlarging diameter as it"approa'ches the impinge- :ment-ring' 42, but it is-to be kept in mind that the entire "body of volume of' the gas-andair is flowing :in such path,: and. not just the outerpor- .tion of'the cone-of gas and air. 1 rotational: speed of thefuel mixture along-the axis of" the mixing chamber D will probably be it less than the speed-within th marginal portions of the cone of'gases. However; thoroughmixing of the gas and-air takes place 'entirely tothe Manifestly,'the

center of the cone whereby efiicient'and satisfactory combustion ''is' bad.

' Itis further to be noted that other desirable results occur when the incoming streams of air are not directed to a singlepoint at which they intersect and-mutually'destroy one another to create merely turbulence and random movement.

The-streams of air intersect the cone of gas at an angle, and tend to-continue their movement longitudinally of the mixinggchamber D and through the impingement ring 42. The, air streams thus inhibit, any tendency of the coneof gas to spread laterally to an excessive degree, and aidin-maintaining the velocity of thefair- "gas mixture through the ring'42. The combustion operation'and the je ting. 0f the fuel. gas. into the chamber Dv cause the .air ,to be drawnin through the V ports '45. 5 However, i once being drawn in and a given an initial velocity, the air 7 streams do not lose theinenergy orv velocity-in useless conflictand interference with one ,another. "Rather, theair streams, because of their unique gdirectional arrangement, cooperate and movesmoothly towardthe ring .42.

For supplying additional air to the fuelprnixture a plurality of secondary air inlet ports- 46 are. formed in. the wall. of the :sleeve- 34 adjacent theriaarwardend of said sleeve and immediately than the. ports. 45v and. are uniformly. spaced- 01 sta gered withrespect to the latter ports. Thus, each. of the ports 45 is positionedsubstantially intermediate each adjacent pair of .-the=ports 46. The angular facing of the ports 45 provides an additional advantage in this respect. since it ;=r esu1ts;.1in the direction across. the. inner; zsides 75;-'

through the ports 45, as illustrated in Fig. 13. The direction of air travel through the ports 45 is seen to be transverse across the openings 46 and at the same time to possess a lateral component inwardly toward the longitudinal center or axis of the chamber D. Further, the directions of movement of said air streams do not pass through the centers or axes of the openings 46, but rather to one side of said axes. The net result of this controlled path of movement of the air streams is to create an enhanced aspirating action through the ports 46 and to cause air to be drawn through said ports in a helical path moving toward the center of the chamber D and simultaneously moving toward the forward open end of said chamber adjacent the combustion chamber E. The three directional components of the paths of movement of the air streams flowing through the ports 45 may be broken down to account for this result. The transverse movement of air streams across the openings 46 achieves the aspirating result and draws air inwardly through said ports 46. The fact that the center or axis of each of the primary air streams passes off center with respect to the secondary air streams results in the helical path of the latter streams. Thirdly, the inward component of the primary air streams toward the axis of the chamber D increases the aspirating effect, tends to move the secondary air streams also toward the mixing chamber axis, and imparts to said secondary air streams a longitudinal component of movement toward the open forward end of the mixing chamber. The utmost use is thus made of the primary air streams to encourage and enhance the flow of the secondary air streams and provide the proper quantities of combustion air for the jet of fuel gas flowing through the orifice 40. The helical flow of the secondary air streams creates additional turbulence for mixing purposes, and the generally inward and forward path of the secondary streams causes the latter to blend into the previously mentioned streams and flow smoothly toward the outlet of the mixing chamber without unduly impairing the forward velocity of said streams.

In actual use, this burner has been found to be extremely efficient and to provide temperatures well above 1500 degrees Fahrenheit without the use of combustion air supplied under pressure, and without the supplying of fuel gas at abnormal pressures. Natural gas is normally furnished at a pressure of 3 to 4 ounces per square inch, and the present invention provides a means of attaining temperatures above 1500 degrees Fahrenheit through the use of such low pressure gas and without requiring the supplemental supply of air under pressure or any other additional equipment. Of course, the burner is also well adapted to use with butane gas under both low and high pressure and for other combustible gases. It is sometimes necessary to adjust the jet cup 38 in accordance with the pressure of various gas supplies, such adjustments being effected by selective positioning of the cup within the bore 31. In general, as the pressure of the gas supply is increased, the cup must be moved away from the chamber D so as to focus the jet of gas flowing from the orifice 40 upon the impingement ring 42.

Of course, it is also desirable to vary the size of the orifice 40 in accordance with the pressure of'the fuel gas supply. Normally, this orifice will be formed by a small drill, and it has been found that the range of drills from No. 60 to No. 80, corresponding to an orifice diameter of from 0.0400 inch to 0.0135 inch, will provide for nearly all fuel pressures encountered. As the fuel gas pressure increases, the size of the orifice is reduced. If the variation in the size of the orifice as drilled with consecutive ones of the series of drills is too great, then the adjustment of the cup 38 within the bore 3'! is used to trim the flame and provide the desired results. As the fuel gas pressure is increased and the size of the orifice is reduced, the velocity of the gas jet, in general, increases. The nearness of the jet offuel gas to the primary air inlets 45 governs the amount of air induced to follow along with the gas stream, and therefore as the fuel gas velocity increases, longitudinal adjustment of the cup 38 may be needed to provide a flame of the desired characteristics. This is true because a high velocity jet does not flare as rapidly as one of lower velocity.

The use of fuel gases of different heat contents may also necessitate changing or adjustment of the orifice in order to obtain optimum results.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A gas burner including, a tubular housing forming a mixing chamber and having one end completely open and one end closed, a fuel gas inlet jet in the closed end of the housing for directing a divergent stream of fuel gas into the mixing chamber, the housing having air inlets adjacent the fuel gas jet, an annular impingement shoulder disposed internally in said housing in adjacent spaced relation to its open end, and a finned fuel gas conductor connected to the closed end of said housing in communication with said fuel gas jet and having transverse openings in its fins.

2. A gas burner as set forth in claim 1 wherein the fin spaced farthest from the housing is imperforate and all of the fins are disposed substantially at right angles to the longitudinal axis of said housing.

ROY M. VARLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 509,710 Williamson, et al. Nov. 28, 1893 703,625 Treen July 1, 1902 1,194,740 Hunter Aug. 15, 1915 1,330,048 Baker Feb. 10, 1920 1,364.094 Fisher Jan. 4, 1921 1,880,649 Young Oct. 4, 1932 1,933,318 Doen Oct. 31, 1933 FOREIGN PATENTS Number Country Date 366,706 Germany Jan. 10, 1923 304,938 Great Britain Jan. 31, 1929 577,854 Germany June 6, 1933 428,878 Great Britain May 21, 1935 I 615,163 Great Britain Jan. 3, 1949

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