US2588895A - Gas burner with flame retaining ports - Google Patents

Description

March 1l, 1952 E E, TAVENER GAS BURNER WITH FLAME RETAINING PORTS 2 SHEETS- SHEET l Filed Jan.. 31, 1947 March 1l, 1952 E. E. TAvENl-:R

E RETAINING PORTS GAS BURNER WITH FLAM" Filed Jan. 31, 1947 WW .W M

MM-WMMM Patented Mar. l1, 1952 GAS BURNER WITH FLAME RETAINING PORT Ernest Edward Tavener, London, England, as,-

sgnor to Keith Blackman Limited, London, England, a corporation of Great Britain Application January 31, 1947, Serial No. 725,442 In Great Britain February 4, 1946l 1 Claim. l

This invention relates to improvements in gas burners. primarily though not exclusively for use in baking ovens, normally in the form of a long tube, that is, long in relation to its Width, provided with a longitudinal slot or slots.

There has arisen a demand for a burner with a continuous, or substantially continuous iiame, but capable of much greater heat output per unit of length than is practicable with burners of the usual types.

It is observed that when the mixture of gas and air issuing from a burner exceeds a certain velocity, it will not remain alight, the flame "lifting oi from the burner opening. If, however, another llame is held adjacent to the issuing mixture, the latter will burn satisfactorily at very` high velocities. This ignition llame, so termed to distinguish it from the. main or high velocity ame, can be fed from the mixture passing to the main flame, in which case the velocity of the mixture supplied to the ignition flame must be considerably reduced before it reaches its combustion point. Onesimple course is to use a restriction orifice in the port leading from the mixture supply to the point of combustion.

For many years, use has been made of a low velocity ignition flame surrounding a main high velocity flame. This ignition llame has usually been fed through a number of small holes, each with a restricted supply, disposed around the main orifice. In other cases an annular ignition iiame has been used.

For the present purpose there is required, in contrast, a substantially continuous main flame, long in relation to its width.

A burner according to the invention presents a main slot (or slots) for the main ilame, bordered along the length thereof, preferably on each side, by a supplementary slot for an ignition llame.

For example, a main central slot may be provided by two strips, separated by a spacer. to give the required width of slot. On each side of this assembly is placed a spacer so formed as to reduce the combustible mixture to a low velocity at the point of combustion. Flanking these spacers are further strips, the whole assembly comprising in this particular case seven elements, of which three are spacers.

The strip and spacer assembly may be iitted into a housing suitable for conveying combustible Vmixture and delivering it to the entrant side of the slots. This housing may conveniently be made from tubing,`slotted to receive the strip assembly, and fitted with cross bolts to prevent distortion of the housing under the inuence of heat. The mixture may be delivered to one end of the housing which may contain a further apertured tube for rationing the mixture longitudinally of the burner to provide even or uneven heating, as required.

A gas burner according to the invention is illustrated in the accompanying drawings in which Fig. 1 is a perspective view and Fig. 2 a cross section of the strip and spacer assembly constituting the burner proper, and Figs. 3 and 4 are a longitudinal section and a cross section, respectively, showing the burner iitted into a housing.

Referring to the drawings, the burner shown presents a central slot Ill for a main flame, bordered along the length thereof on each side by a supplementary slot I I for an ignition flame. The central slot. I0 is provided by two strips I2, separated by a spacer I3, to give the required width of opening. On each side of this assembly is placed a spacer I4 so formed as to reduce the combustible mixture for the ignition flame to a low velocity at the point of combustion. Flanking these spacers I4 are outer strips I5. The strip and spacer assembly shown thus comprises seven elements, of which three are spacers.

The assembly is tted into a housing I6 suitable for conveying a combustible mixture, and delivering it to the entrant side of the slots I0. II. The housing IG shown is made from tubing, slotted at Il to receive the strip assembly, and tted with cross bolts I8 to prevent distortion of the tube under the influence of heat. The mixture enters one end of the tube at I9. 20 denotes a perforated rationing tube fitted Wthin the housing IB and serving to ration the mixture longitudinally of the burner to provide even or uneven heating, as required. Heat distribution along the length of the burner may be further regulated by adjustment of a conical valve 2| co-operating with an orifice 22 in a partition 23 fitted into the inlet end of the housing I 6.

The strips I2, I 5 may be held together by rivets, screws, welding or other means. 24 denotes straps for retaining the strip and spacer assembly in position in the housing I6. For convenience of manufacture, the spacers |31, I4 are preferably continuous, but serrated, the serrations being formed to permit the passage of mixture between the strips forming the boundaries of the burner outlets I0, Il. In the vignition spacers I4 the openings are each shorter at the entrant side than at the discharge point, whereby the velocity of the issuing mixture is reduced..

Again thin spacers may be used to provide the ignition name openings Il, the proportions being such as to cause considerable friction to the flow.

VAlso the length of passage from the entrant side to the combustion side may be selected to apply 5 the requiredireduction of'the velocity. Such are rangements may be usedseparately,1 or.:irr combination.

An incidental advantage of the use of a narrovn-f ignition ame opening is that there is less like- 10` lihood of lighting back. in fact; lightingbackV is virtually impossible under normal operating conditions with a very narrowopjening.-y

With the use of a very narrow ignitionilame.:l

opening il, a burner such as describedilcamzbe115,.

made very exible in performance, as,.vvithv a. high mixture pressure, a considerablelamountiof gas can be consumed per unit of length, the main ame being kept alight by the ignition name-orf: ames. can vbefmade .relativelyv low? before .the velocity of:` thevvmixtureftraversing themain slot] 0 (orfslots) is.- reduced' sufficiently;i to.V cause.y riskof lighting; back.A

Thefinvention .is 2not limited to details. of. con-v struction. Thus, the relative.v heights of. the spacersv and .thestrips mayvary; e.. g., the spacers may be-.sunk below the level of, theA strips, .as shown.

The .form of the serrations in the spacers. may very to. provide :continuous or interruptedflames.

Whilelhave described a burner. which. gives. one central main .flame and an ignition flame at. each side, the arrangement may be suchiastto provide.. one` .main Y flame and'v onev ignition. flame, or two main names. placed one on. each. side of. one4 ignition ame.

The relative widths .and/or thicknesses. of.' the strips and spacers may.Y vary. For instance, for..

protectionpurposes we may`V bring the. outer. 4m

The outermost strips may be elinr'iated, their 45 place bein'gv taken by', the edgesorftheiburner.

housing.

Conversely, the rate of gas consumption 20 What is claimed is:

A gas burner including a longitudinally slotted tube, an assembly mounted in the slot in the tube and contacting the sides of the slot, said assembly comprising a plurality of plane parallel strip members-and :plane-sided serrated spacer. members-:..havingfoutwardly pointed serrations' interposed between and contacting neighbouring strip members for spacing Vsaid strip members apart,

thepointsof theserrations being ush with the outer edgesofmeighbouring strip members, said strip and spacer members extending in parallel relation .longitudinally-"of said tube with their planel sides` in fcontact, these serrations extending belowtl'ie paralleli stripV members, said strip members-and. saidspacer members, collectively forming ..at.least one main slot and at least one supplementary slot constituting passages for the owpffcombustion mixture to the outlet Vdefined by the upper edges of said strip and spacer members, thel .entr-ance'- to.. thea` main. slot being sub:-

stantially-f unobstructed byf a spacer.v memberi having widely f spaced i serrations. and interposed: between tWof striplmemb'ers, and .the entrance ato? 25"the supplementaryA slot being. considerably ob structed by a spacer.` member4 having. closely spaced serrations andi interposedbetween. two

strip members:v

Ei'tNlihSTV EDWARD TAVENER-i..

REFERENCES CITED;

The*following'referencesarebof record in theM Number: Name? Y Datei.

73315235. Machlet:v July '1, 1903.. '791,923 Machlet; .Jr.'.. Junef', L1905;

1,105,031.; Hagemeyer .July.`28, 1914.; 1,519,056` Risinger Dee.y 9,1,19241 2,396,800. Mills". .Mar.' 19,1,1946"=v 2,428,271 Ensignzet al.' Sept. 30,;.194'71` FOREIGN PATENTS f. Number Country,v4 Date 259,868.. Germanyf. May 15,- 1913 501,143.

' Great-Britain f Feb.. 22, 1939..

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