US2001739A - Gas burner - Google Patents

Description

Patented May 21, 1935 UNITED STATES PATENT OFFICE GAS BURNER Application October 3, 1933, Serial No. 691,904

6 Claims.

This invention relates to gas burners and particularly to one which is adapted to burn a liquefied petroleum gas such as is marketed in pressure cylinders and utilized at the usual tank 5 pressure of 50-150 pounds per square inch. This burner is well adapted .to burn successfully and smokelessly that type of fuel at widely varying rates, which may range from 0.10 to 15 cubic feet per hour. It has been found useful in portable heaters intended to prevent freezing perishable products being transported in subzero weather. Such a heater is disclosed and claimed in the copending application of Carl A.

Claesson, Serial No. 666,558, filed April 17, 1933. It is an object of this invention to provide a simple and reliable gas burner that will successfully handle widely varying flows of gas generated from a liquefied petroleum gas of high heat value, such as is marketed in pressure cyl- 0 inders and utilizedat the usual tank pressure of 50-150 pounds per square inch, and without the use of a pilot or auxiliary ignition device.

Another object is to provide a gas burner which will not be subject to extinguishment by accidental drafts, such as are encountered in a portable heater used in refrigerator cars in winter, even though the minimum or pilot gas flame be burning.

Another object is to provide a gas burner that i will not coke or become sooty at low gas rates, and in which the gas may quicklybe turned to a high or low flow rate as by an automatic temperature controller, without danger of flashing back into the burner tube or becoming extini guished.

These and other objects and advantages will become apparent from the description which follows, and from the accompanying drawing, which forms a part of this specification and illustrates l a preferred embodiment of the invention.

In the drawing:

Figure 1 is a vertical sectional elevation of a gas burner embodying the invention.

Figure 2 is a plan view of the burner shown F in Figure 1.

Referring more particularly to Fig. 1, the numeral l0 illustrates a base plate or support on which the burner proper may be mounted. The tube of the burner'is illustrated as being of varying diameter, the lower and larger portion ll, being provided near the base ID with a number of air ports l2. The intermediate portion of the tube is preferably somewhat reduced in cross-section as at l3, to form a modified Venturi throat and insure adequate air inspiration. The

upper end ll of the tube is again larger in diameter to accommodate the spaced perforated discs or bafiles which will be described below.

The gas nozzle I5 is concentric with the burner tube axis and is preferably fitted with a removable nozzle tip IB having a small diameter bore, say that made by a No. 80 drill or about 0.0135 inch. This is desirable for two reasons: first, the requirement for a reasonablyhigh velocity gas jet at low gas rates, in order to en train an adequate amount of air through ports 12 to obtain a proper mixture; and second, to prevent too great a rate of gas flow by adequate throttling when full gas tank pressure of 50-150 pounds per square inch is admitted to nozzle I5. 15 The tip I5 is preferably mounted some distance above the air ports l2, in order to prevent accidental drafts through these ports from interfering with the jet of gas from l6, particularly at low gas rates.

The upper end it of the burner tube is illustrated as being provided with three equally spaced radial bosses H which are bored and threaded as at l8 for machine screws l9. Three screws l9 are used to secure the shroud or shield 2|] around and above the top of the burner, to serve as a protection to the low or pilot flame when little heat is required, and also to admit auxiliary air to the flame when high gas rates are employed and the flame fills and burns out of the top of the shroud 20. Perforations 2| are made in shroud 20 at some distance above the top of bumer tip l4, and appear to increase its effectiveness. Loc knuts 22 may be added to screws I! to hold the shroud in place against the bosses l1.

Inside the upper end M of the burner tube and spaced from the end thereof is a perforated metal disc or flash back preventer baflle 23. This is drilled with a number of small holes 24, for example 30 holes about 0.05 inch in diameter. Secured to disc 23 and spaced therefrom by a metal stud 25 is a second smaller disc or baflle 26, which may also be perforated with approximately the same number of holes. A metal sleeve 21 fits snugly in the bore of the upper end l4 and rests on top of the outer unperforated edge of the lower disc 23.

A groove 28 around sleeve 21 is adapted to receive the ends of machine screws l9, previously mentioned, which look sleeve 21 and discs 23 and 26 in place. An inwardly turned flange 29 at the upper end of sleeve 21 is preferably substantially flush with the outer edge of upper disc 26 and is preferably spaced about inch above it.

This provides an inwardly curved path for the greater part of the gas-air mixture from the space within sleeve 21 above disc 23 and has been found to effectively prevent the burner flashing back or becoming extinguished at low gas rates.

Thus it is apparent that a very simple and compact burner structure has been illustrated and described, which has been found most successful in extended tests, and which adequately fulfils the requirement of suitable combustion of high heat value liquefied petroleum gas at very widely varying rates and at full tank pressure. The invention appears to reside in the particular arrangement of air ports, gas nozzle, mixing tube and particularly in the spaced bafiles and the flange means at the burner tip to direct the flow of gas and air inwardly toward the axis of the burner. It has been found effective in operations involving a gas flow as low as 0.10 cubic foot per hour and may thus serve in place of the usual auxiliary pilot burner during intermediate periods between full flow operation at rates of gas fiow as high as 15 cubic feet per hour or more.

Although a specific construction embodying this invention has been described and illustrated, it is to be understood that the invention is not limited to that arrangement, and all such modifications and changes as' come within the scope of the following claims are embraced thereby.

I claim:

' 1. A gas burner comprising a vertical tube, air ports in said tube, a gas nozzle extending into said tube and terminating substantially above said air ports, a perforated bafiie in said tube above said nozzle, a second perforated baflle spaced above said first named baffle with its periphery spaced from the bore of said tube, a flange extending inwardly from the bore of said tube above said second named bafiie, with its inner edge substantially aligned with the periphery of said bafile, and a shroud surrounding said tube and extending above the top thereof.

2. A gas burner comprising a vertical tube, air ports in said tube, a gas nozzle extending into said tube and terminating above said air ports,

a perforated baffie in said tube above said nozzle, a second perforated bafile spaced above said first named bafiie with its periphery spaced from the bore of said tube, and a flange extending inwardly from the bore of said tube above said second named bafiie, with its inner edge substantially aligned with the periphery of said bafile.

3. A gas burner comprising a vertical tube, means for forming an air-gas mixture in said tube, a perforated baflle in said tube intermediate its length, a second perforated bafile spaced above said first named bafile with its periphery spaced from the bore of said tube, and a flange extending inwardly from the bore of said tube above said second named bafile, with its inner edge substantially aligned with the periphery of said bafile.

4. A gas burner comprising a vertical tube, means for forming an air-gas mixture in said tube, a perforated baffle in said tube intermediate its length, a second baflle spaced above said first named baffle with its periphery spaced from the bore of said tube, and a flange extending,

inwardly above said second named'bafile and forming with said baffle an inwardly curving path for said gas-air mixture.

5. A gas burner comprising a vertical tube,

means for introducing an air-gas mixture into said tube, a perforated bafile in said tube intermediate its length, a second bafile spaced above said first named baflle and of smaller diameter than the bore of said tube, and means above said named bafiie and of smaller diameter than the bore of said tube, and a flange extending inwardly above said second-named bafiie and forming therewith an inwardly curving path for said airgas mixture.

JOHN R. MAcGREqOR.

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