US1818783A - Gas burner - Google Patents

Description

Au 11, 1931. v. o. BEAM. 1,818,783

GAS BURNER Filed Oct. 26, 1929 [NW/V7221? -VO.BEAM BY M 4 M A TTORNET' Patented Aug. 11, 1931 UNITED STATES PATENT OFFICE VILYNN O. BEAM, 01 TOLEDO, OHIO, ASSIGNOR TO SURFACE COMBUSTION CORPORA- 'IION, OF TOLEDO, OHIO, A CORPORATION OF NEW YORK GAS BURNER Application filed (letober 26, 1929. Serial No. 402,587.

This invention relates to improvements in gas burners of the Bunsen type wherein a jet of'gas discharging into a tube entrains air pressure again prevails. It will be rea that this sensitivity to gas sup-- through side ports in the tube to form a combustible mixture. In normal operation of burners of this type, the velocity of the mixture in the tube is only slightly in excess of the rate of flame propagation thereof and the mixture burns in relatively close proximity to the outlet where, due to expansion of the mixture, its velocity is substantially the same as the rate of flame propagation thereof. Such burners,however, are very sensitive to variations in the supply pressure of the gas. If the supply pressure materially increases, the velocity of the mixture remains in excess of the rate of flame propagation thereof fora considerable distance beyond the outlet of the tube and hence the flame is easily blown away. On the other hand, if the supply pressure of the gas appreciably decreases, combustion will cease or will flash back to the gas et orifice where it will tend to remain even when the gas pressure again increases. When back flash has occurred, the flame must be extinguished and the burner relit when normal as (fily appreciate ply pressure very materially limits the usefulness of the ordinary Bunsen type burners and practically prohibits their use where conv stant attention is impractical as for example in domestic house-heating furnaces. To counteract the tendency of the flame to blow off as aforesaid, it has been proposed to reduce the velocity of the mixture by bafliing it as by interposing asolid body in the path of flow of the mixture or by causing two or more streams of the mixture to impinge against each other. Such expedients, however while useful, are necessarily of limited application.

It is an object of my invention to provide agas burner of the jet and tube type which shall function efliciently within the extremes of gas pressure likely to prevail in gas distributing systems without tending to blow ofi at high pressures and without tendency to .flash back to the gas jet orifice at negligible pressures.

burner adapted to burn gas of low B. t. u.

value such as artificial gas, both views being scale drawings of burners, the scale being twice that of the preferred size of the burner.

Fig. 3 merely illustrates a plurality of the burners mounted on a common manifold to form a multi-tube burner such as may be used in the firepots of domestic house heating furnaces.

As illustrated in Fig. 3, the improved burners which are generally indicated by letter B may be mounted on a gas supply manifold M of any suitable or preferred form and P indicates a pilot of any suitable or preferred form for igniting the burners.

The two burners shown in Figs. 1 and 2 are of the same general construction except as to proportions necessary to adapt the burners to gases of different B. t. u. value and therefore in order to simplify the description, the same reference numerals as are used in Fig. 1 are used in Fig. 2 to designate corresponding parts, the numerals in Fig. 2 being prlmed, and it will therefore be understood that even though the primed reference nu- 'merals' may not be referred to hereinafter,

nevertheless the description making use of the unprimed reference numeral is to be taken as applying with equal force to Fig. 2.

In accordance with this invention, the

metrically opposedair intake ports 11.

The side walls 10' are preferably of'heat resisting alloy whereas the lower walls 8 may be of brass, the lower ortion of the tube comprising the walls 10 eingpressed over a reduced portion 12 of the lower bore walls 8. The upper bore walls 10 being of heat resisting alloy, will not oxidize at high temperatures.

An externally threaded extension 13 having a bore 14 of appropriate .size is provided at the lower end of the burner to permit it tobe screwed into a as supply manifold or the like as will be rea ily understood.

It will be noted that the burners shown in Figs. 1 and 2 are of substantially the same length from the outlet of the gas jet orifice 7 to the top of the upper bore 5 but diifer as to diameters of their bores, their air intake ports and their gas jet orifice. This is explained by the fact that the burner shown in Fig. 1 is designed for burning natural gas and that in Fig. 2 for artificial gas such as is usually distributed in city mains. As is well known, natural gas requires a much greater volume of air for combustion than does artificial gas and generally speaking the two gases have considerably difl'erent combustion characteristics. However, the principles involved in both burners are the same as will presently appear.

In accordance with this invention, the relationship between the lower bore 6, the gas jet orifice 7 and the lower air intake ports 9 is such that with gas at extremely low pressure, the mixture of air and gas will nevertheless be such that the rate of flame propagation thereof is less than the velocity of the mixture within the bore 6. In other words, for a given length of bore 6, the relationship between the cross sectional areas of the bore 6, the air intake ports 9 and the gas jet orifice 7 is such that at low gas pressures as may be deemed negligible as compared with higher pressures usually available in a gas distributing system, the normal tendency is for the gas to burn at the top of the bore 6 where air is available from the adj acent air intake ports 11. Where this relationship prevails, the flame will not flash back to the gas jet orifice 7. The brass body 8 wherein the bore 6 is formed is also a'factor since itv will remain relatively cool as compared with steel due to the greater heat conductivity of brass and consequently the gas and air entering the bore 6 will not be appreciably preheated before reaching the outlet of the bore 6 which preheating would tend to increase the rate of flame propagation of the mixture.

The relationship between the upper bore 5 and the air intake ports 11 at the bottom thereof is such that when the mixture leaving the top of the lower bore 6 has a velocity which is materially greater than the rate of flame propagation thereof, the flame will automatically shift from the top of the bore 6 to the top of the bore 5. In other words, for a given length of bore 5, the relationship between the cross sectional area of the bore 5, the air intake ports 11 and the lower bore 6 is such that when the velocity of the mixture air under the influence of the entraining efl'ect of the gas issuing from the jet orifice 7.

The above description of the invention is believed to be suflicient to enable one skilled in the art to make and usethe same. already stated, the burner shown in Fig. 1 is adapted for burning natural gas and that shown in Fig. 2 for burning artificial gas such as is usually supplied to city gas mains, both burners being practical embodiments of the invention.

What is claimed. is

1. A gas burner comprising means forming a relatively deep well, the diameter of which at its top and for a substantial distance down is greater than the diameter of the balance of the well, a gas jet orifice in the bottom of the well, lower air intake ports in the sides of said means adjacent the bottom of the well, upper air intake ports in the sides of said means where the two well portions meet, the relative areas of the gas jet orifice, the lower side air intake ports and the bore of the lower portion of the well being such that with gas issuing from said jet orifice under relatively high pressure, there will be formed a gas and air mixture, the rate of flame propagation of which will be less than the velocity thereof in said bore and the relative areas of the bore of the upper well portion and said upper air intake ports being such that the resultant mixture will have a velocity not materially in excess of the rate of flame propagation thereof. I

2. A gas burner comprising means forming a relatively deep well, the diameter of which at its top and for a substantialdistance down is greater than the diameter of the balance of the well, a gas jet orifice in the bottom of the well, lower air intake ports in the sides of said means adjacent the bottom of the well, upper air intake ports in the sides of said means where the two well portions meet, the relative areas of the gas jet orifice, the lower side air intake ports and the bore of the lower portion of the well being such that with gas issuing from said jet orifice under relatively negligible pressure, there will be formed a gas and air mixture the rate. of flame propagation of which will be less than the velocity thereof in said bore but substantially equal to such velocity at the region where it receives air from said upper air intake ports whereb said mixture will burn intermediate the en s of said well.

, 3. A gas burner comprising means formin two axially abutting bores ofrelatively di erent diameters, a gas jet orifice formed in the outer end of the bore of lesser diameter, lower air intake ports in the sides of said bore adjacent the gas jet orifice, u per air intake ports in the sides of the bore 0 greater diameter adjacent the bore of smaller diameter, said lower intake ports having a sufliciently small cross sectional area to restrict the entrainment of air by the gas issuin from the jet orifice nozzle to such a degree t at a mix-' ture of air and gas discharging from the bore of lesser diameter will be rich in gas, said upper intake ports having a'sufliciently small cross sectional area to restrict the entrainment of air by the mixture issuin from the bore of lesser diameter to such a egree that the air and gas mixture discharging from the bore of greater diameter will contain suflicient air for complete combustiori.

In testimony whereof I aflix my si ature.

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