US2988138A - Gas burning device - Google Patents

Description

June 1 1961 w. BRZOZOWSKI GAS BURNING DEVICE Filed NOV. 13, 1956 W R miwwflmfi m h h mi [1 1 8% w m m & w W W mm Mm INVENTOR azoa/az Q mm 3 ATTORNEY 2,988,138 GAS BURNING DEVICE Witold Brzozowski, Montehello, Quebec, Canada Filed Nov. 13, 1956, Ser. No. 621,773 3 Claims. (Cl. 158-7) This invention relatm to an air-gaseous fuel mixing and burning method and apparatus.

Air gaseous fuel mixing devices are known in which the air enters an elongated passage and leaves this passage with entrained fuel. The fuel is introduced into the passage intermediate the inlet and the outlet. Some of these burners have an annular fuel inlet which surrounds the gas passage and the gas adjustment is performed at a point remote from the annular inlet. This has the disadvantage that there is a pressure drop once at the reg ulator then again at the annular inlet. This means that if the mixture is adjusted for certain air pressure it will not be the same for other pressures or in other words, if the air fuel issue is adjusted correctly at the inlet but by the time it has been choked the second time the mixture is incorrect. Previously, also, the fuel air mixture has been led from the inlet directly to an outlet and then into a premixing chamber or burner without thorough attention to complete mixing.

Also, previous burners have not been able to employ a high velocity air-fuel stream, because the flame would be blown out.

The present invention avoids these disadvantages and provides certain positive advantages, as will be explained.

Applicants development According to the invention there is provided a burner which has the following features. It includes a tubular housing having an inlet at one end and forming an axial chamber therein, and a reduced-diameter nozzle downstream of the axial chamber and in axial alignment therewith. Baifle means extend transversely of the nozzle and axial chamber and forms the downstream end of the chamber. The bafl le means include axial passage portions circumposed about the nozzle for directing a mixture of pilot fuel axially along the exterior of the nozzle. A second housing extends axially from the first housing and provides an axial combustion chamber circumposed about and spaced from and extending axially beyond the nozzle and baffle means. Second baflle means, downstream of the first baflle means, include axial passage portions to permit pilot fuel to move through it. Ignition means are located in the combustion chamber downstream of the second bafiie means for igniting the pilot fuel. The passage portions and the two baffle means define an axial tortuous path through which the pilot fuel must flow along the nozzle. An annular chamber including a fuel inlet is circurnposed about the axial chamber and includes an axial passage surrounding the first baflle means mentioned, this axial passage opening upstream of the second baflle means.

Preferably the second baffle means is an annular collar on the nozzle peripherally spaced from the inner surface of the combustion chamber. Preferably also the first and second baffle means include radially off-set apertures defining the tortuous path.

Having thus generally described the nature of the invention, a preferred embodiment of it will be described in more detail by Way of example and by reference to the accompanying drawings, in which:

FIGURE 1 is a side elevation of the preferred apparatus.

FIGURE 2 is a vertical cross-section through the apparatus of FIGURE 1.

Patented June 13, 1961 ice FIGURE 3 is a partial vertical cross-section substantial along the line 33 of FIGURE 2.

FIGURE 4 is a fragmentary view showing an alternative arrangement for the combustion initiating apparatus showing another form of baffle means.

Reference will now be made in more detail to the drawings.

General arrangement A represents a main, elongated tubular housing of the gas mixing apparatus of this preferred form of the invention, B a tubular housing which encloses a pre-mixing chamber and, C a further tubular housing which houses the combustion chamber. It is provided with a refractory lining.

The housing A has an inlet end provided with a flange 15.

The housing A also has an outlet end having a flange 17. The housing B has a flange at its inlet end 19. The flanges 17 and 19 are bolted together by bolts 21 to secure the housings A and B together. The housing B has a flange 23 spaced from its outlet end, which is connected to a flange 25 on the housing C. Bolts 27 secure the flange 25 to the flange 23 and thus the housing B to the housing C.

The housing A has intermediate its inlet end and its outlet end an inlet tube 29 for gaseous fuel. The inlet end of the housing A is connected to a source of air under pressure, for example, to a blower. This is not shown.

Within the housing A is mounted a passage forming member 31, which is a tapered tube having one end forming a snug fit with the outlet end of the housing A and the other end concentric with the walls of the housing A, thus forming a space between the housing A and member 31. The inner end of the tube 31 is spaced to the rear of the inlet tube 29. The inlet end of the tube 31 is provided with an annular lip 33.

Within the tube 31 and adjacent its outlet end, is a nest of pipes 35 in this instance four pipes which have their outlet ends adjacent to the outside of the tube 31 and their inlet ends toward the axis of the tube.

In the rear of the lip 33 of the tube 31 is a piston 41, which works within the housing A which constitutes its cylinder. The piston has a forward end or lip 43 adapted to register with the lip 33. The piston also has piston rings 45 to form a seal between it and the walls of the tube A.

To the piston is joined a connecting member 47. To the connecting member 47 is connected a strut 49. The rear end of the strut 49 is pivotally connected to a pivot 51 mounted on a bell-crank member 53 pivoted as at 55 to a bracket 57 which is bolted as at 58 to the wall of the cylinder A.

Acting on the rear end of the bell-crank member 53 is a spring 59 which is housed in a housing 61 protruding from the casing A and integrally connected to it. The housing 61 has an outer tapped end 63 within which is mounted an adjusting screw 65 by which the compression of the spring 59 may be adjusted.

Acting on the forward end of the bell-crank member 53 is an adjusting screw 69 which is threadably related to a protruding threaded collar 71 on the wall of the cylinder A.

In advance of the flange 23 is an annular flange 25 which extends inward from the wall of the cylinder C and which is abuted by the flange 23. Spaced from the flange 23 is an annular flange 26 extending from the end of cylinder B and forming a baffie means. At its inner edge, flange 26 meets a tube 79 which is carried by flange 26 concentric with cylinder B and which extends forward into the cylinder C. The tube 79 serves as a nozzle. Flange 26 contains a series of perforations 26b around the flange concentric with the cylinder B and tube 79.

In advance of the flange 26 is an annular ring or second baffle means 81 which extends between the tube 79 and the refractory lining 14 within the tube C, this ring is also perforated as at 81a but the perforations are not in register with the perforations 26b.

Spaced on the inner surface of cylinder C from annular flange 25 is an inwardly extending annular flange 29. Flange 29 abuts the end of the refractory 14. Annular flange 25, annular flange 29, the wall of cylinder C thcrebetween, and the wall of cylinder B lying between flanges 23 and 26 together define an annular chamber 28.

The integral combination of the cylinder B, flange 26 and tube 79 are separated from the annular flange 29 by an annular space, which provides an outlet to chamber 28.

A gas inlet tube 80 is connected to the wall of the tube -C so as to lead to the chamber 28.

Also, there is a spark plug 85 mounted in the wall of the cylinder C and having its points within the cylinder C just in advance of the baflie 81.

Operation In operation, the gap between the lip 33 and the lip 43 is adjusted by manipulation of the adjusting screw 69. This gap can be adjusted to any desired degree to allow the desired amount of gaseous fuel to enter the stream of air which is induced by the blower to come in through the inlet end of the tube A.

The gas air mixture entering the gap between the lips 33 and 43, passes on into the diffusing tube 31 and is diffused and slowed up by this tube, thence a portion of it enters the tubes 35 by which it is spread and caused to migrate to the outer portion of the outlet of the tube A. Another portion of this mixture enters the gap between the tubes 35 and passes into the pre-mixing chamber B.

A major portion of the fuel air mixture which passes into the pre-mixin-g chamber in the cylinder B passes directly into the nozzle 79 and into the combustion chamber C. A minor portion of the mixture passes through the baffle 26 and is mixed with gas entering from the annular chamber 28 and is baffled and slowed up and then passes out through the openings 81a and baflde means 81 and is ignited in the annular space about the nozzle 79 between it and the refractory walls of the combustion chamber C, provide a pilot flame.

The mixture is slowed down and burned in the annular chamber. The flame originating in this chamber ignites the mixture coming out of the center of the nozzle 79 and causes a gradual convergence of the flame until the entire mixture is burned as it passes through the combustion chamber and leaves the chamber at the mouth or outlet.

The function of the pilot jet gas supply introduced by the pipe 80 is to keep a constant flame around the nozzle 79 when the main fuel supply is shut-off. This is important in internal installations, for example, in boilers. Without the pilot flame, the ignition may be delayed and the boiler filled up with a gas-mixture, belated ignition of which may result in an explosion.

The velocity of the mixture may be very high. For example, if pressure of 1 pound air-pressure is employed, the velocity from the nozzle 79 may be over 300 feet per second, for example as high as 400 feet per second.

This burner can be used with any gaseous fuel, for example, natural gas, city gas, propane or other hydrocarbon fuel in gaseous form.

The batfling means need not necessarily be a per- 4 forated plate 81 as shown in FIGURE 2 but may take other forms, for example, that of a collar 82 as shown in FIGURE 4 surrounding the end of the nozzle 79.

In a gas mixer of the type shown where the tube A is about 2 inches in diameter, the gap between the lip 33 and the lip 43 would normally be about one thirtysecond of an inch when full open and can be adjusted inwardly from that gap depending on the richness of the mixture desired and the kind of gas used. The taper in the mixing chamber is roughly 8 to 10 degrees from the wall of the tube A.

Advantages The tubes have the effect of diffusing the gas air mixture with very little pressure drop and at the same time exert no flame-holding effect (flash-back or backfiring).

This type of burner burns at a very high rate of combustion (B.t.u. per cubic foot of combustion space). Combustion is good also when air supplied under high pressure, if gas is supplied under the same pressure as the air, the fuel ratio does not change even if choking takes place downstream of the burner or upstream of the mixer.

I claim:

1. A burner for a mixture of gaseous fuel and air comprising a tubular housing having an inlet at one end and forming an axial chamber therein, a reduced diameter nozzle down stream of said axial chamber and in axial alignment therewith, baffle means extending transversely of said nozzle and said axial chamber and forming the down stream end of said chamber, said baffle means including axial passage portions circumposed about said nozzle for directing a mixture of pilot fuel axially along the exterior of said nozzle, a second housing extending axially from said first housing and providing an axial combustion chamber circumposed about and spaced from and extending axially beyond said nozzle and bafile means, a second baflie means down stream of said first mentioned baffle means and including axial passage portions to permit pilot fuel to move therethrough, ignition means in said combustion chamber for igniting the pilot fuel, said passage portions of the baffle means defining an axial tortuous path through which pilot fuel must flow along said nozzle, and an annular chamber including a fuel inlet, said annular chamber being circumposed about said axial chamber and including an axial passage surrounding said first mentioned baflle means and opening upstream of said second baffle means.

2. The structure of claim 1; said second bafile means comprising an annular collar on said nozzle and peripherally spaced from the inner surface of the combustion chamber.

3. The structure of claim 1; said first mentioned and second baffle means including radially oflset apertures defining said tortuous path.

References Cited in the file of this patent UNITED STATES PATENTS 686,625 Machlet Nov. 12, 1901 1,519,649 Anderson Dec. 16, 1924 1,702,298 Hetsch Feb. 19, 1929 1,790,927 Kreager Feb. 3, 1931 2,121,948 Borland June 28, 1938 2,214,284 Sayers Sept. 10, 1940 2,237,889 Rickert Apr. 8, 1941 2,518,544 Anthes Aug. 15, 1950 2,627,308 Clark Feb. 3, 1953 2,767,784 Dean Oct. 23, 1956 2,784,778 Milton Mar. 12, 1957 2,785,742 Lovett Mar. 19, 1957

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