Oil Burner

Abstract

An oil burner for connection to the wall of a boiler or steam generator having an axially movable burner pipe which extends through an opening in the rear wall of the burner, and an air measurement device in the form of a venturi meter surrounding the burner pipe and including a first truncated cone of a venturi meter which is coupled to the air chamber for regulating the air supply. A second truncated cone surrounds the oil burner nozzle and includes a means for measuring the amount of air pressure.

Description

This invention relates to an oil burner which is attached to the wall of a steam generator or boiler.

In the present invention, an axially movable burner pipe extends through an opening in the rear burner wall. The burner pipe is surrounded by an air measuring device which is connected to an air chamber. During the operation of the burner, the air stream from the air chamber is supplied to the chamber which surrounds the burner pipe and which is generally known as an air measuring device. In the air measuring device, the air stream travels parallel with respect to the burner axis and is then admitted to the nozzle head. At that point, the air mixes with the fuel forming a burner flame.

In conventional burners, it is often difficult to supply the burner with an optimum supply of air. This is particularly true when the burners are operated intermittantly. As is commonly known, the admittance of too much air, as well as the admittance of not enough air is always disadvantageous. A certain improvement could be achieved in making the burner pipe slidable. However, this would not be adequate, particularly when the burners are not operated at full power.

Accordingly, the present invention provides an oil burner in which the air can be supplied with stoichiometrical exactness with respect to the consumed oil. Furthermore, the invention also provides an oil burner which is compact, and not subject to breakdowns, so that operational interruptions are almost avoided. The oil burner is attached to the wall of a steam generator or boiler with the burner pipe being axially movable and extending through an opening in the rear wall of the burner. An air measurement device surrounds the burner pipe. The air measurement device in the form of a venturi meter is connected to an air chamber. A short truncated cone of the venturi meter is connected with the air chamber. Means are provided within the truncated cone for regulating the air supply. Another and longer truncated cone of the venturi meter surrounds the oil burner nozzle. At its smallest diameter, the venturi meter, as well as the air chamber are provided with air pressure measuring means. These measures make it possible for the air supply to be exactly regulated with respect to the burning fuel supply. The air pressure measuring means in the venturi meter, as well as the air chamber, permit an exact calculation between these two air pressure measuring means, so that the regulator means at the air inlet port of the venturi meter can be adjusted to its optimum value.

A particularly compact construction of the oil burner is possible since a drum slide surrounds the air inlet port for regulating the air supply. The drum slide is axially slideable by means of an actuating rod which extends through an opening in the rear wall. The height of the drum slide corresponds with the distance between the air inlet port and the venturi meter from the rear wall of the burner.

Another advantageous feature of the invention is that a screen is provided in front of the air inlet port. The air which is admitted into the venturi meter is thus completely whirl free. An even stream of air flows through the venturi meter so that a lateral admittance of air to the air chamber is guaranteed.

In several tests, it was found that the optimum burning of the fuel can be obtained by dissolving the air supply into quantity regulated individual annular air streams. This can be achieved in providing a plurality of coaxially arranged venturi meters, which are provided with air pressure measuring means at their smallest diameter. The air supply regulation can be carried out either by the drum slide, or by simply making one of the coaxially arranged venturi meters slideable. This also permits a change in the relative angle of inclination of the venturi meter walls.

It is therefore an object according to the present invention to provide an improved oil burner which assures the complete combustion between oil and air during its operation.

It is another object according to the present invention to provide an improved oil burner which is simple in design, efficient, and reliable in operation.

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawing which discloses the embodiments of the invention. It is to be understood, however, that the drawing is designed for the purpose of illustration only and not as a definition of the limits of the invention.

In the drawing, wherein similar reference characters denote similar elements throughout the several views:

FIG. 1 shows an oil burner in accordance with the invention with a venturi meter and a drum slide;

FIG. 2 shows an oil burner with two coaxially arranged venturi meters;

FIG. 3 shows an oil burner with three coaxially arranged venturi meters;

FIG. 4 shows an oil burner with two venturi meters and additional gas nozzles;

FIG. 5 shows a combined oil and gas burner having a screen at the air entrance opening of the venturi meter in the oil operating position;

FIG. 6 shows the burner nozzle according to FIG. 5 in the gas operating position;

FIG. 7 shows an oil burner with a venturi meter and additional air exit nozzles at the exit opening of the venturi meter; and,

FIG. 8 shows an oil burner with a venturi meter and a cylindrical exit piece.

Oil burner 1, shown in FIG. 1, is attached to a wall 2 of a steam generator or boiler 2, and is limited by a rear wall 3. A burner pipe 4 is provided on the burner axis, and is movable in axial direction. Burner pipe 4 extends through an opening in the rear wall 3, and is provided with the required connections for the fuel supply. On the opposite end of burner pipe 4, the side which is directed towards the steam generator or boiler, the burner pipe carries a burner nozzle 14.

The air regulator, which surrounds the burner pipe is a venturi meter 5, and consists of a shorter portion 6, which is the air entrance side, and a longer portion 7 which surrounds burner nozzle 14. The angle of inclination of shorter portion 6 is preferably 20.degree.-22.degree., which is the optimum value derived from numerous tests. The angle of inclination of longer part 7 is in the range of 5.degree.-15.degree.. Longer part 7 connects with a connecting exit piece 8 in the direction of the combustion chamber. The narrowest part 9 of venturi meter 5 is provided with a pressure meter 10. A further measuring member 12 is provided in air chamber 17.

The difference in pressure is measured at measuring points 10 and 12 via the air chamber which surrounds the venturi meter and corresponding feed lines. This results in a measuring value of 13, allowing one to calculate the amount of the air stream in the venturi meter with stoichiometrical exactness. By means of manual or automatic control devices (not shown), the amount of air can be adjusted to the time period of the amount of burning oil. The air is controlled by a drum slide 15 which encompasses the air entrance opening. Drum slide 15 can be actuated by a rod 16 which extends through an opening in burner wall 3. The height of drum slide 15 is designed so that the air supply can be completely shut off.

In the embodiment shown in FIG. 2, two venturi meters 5a and 5b are provided. To improve the air-stream guidance, the venturi meters are provided with guide rings 18 at the entrance opening which effect a radial entrance of the air stream into the venturi meter. The slit which is formed by the guide rings 18 can be closed off by means of drum slide 15, so that only the inside of venturi meter 5b receives air.

In accordance with pressure measuring point 10 in the venturi meter shown in FIG. 1, the smallest diameter of venturi meter 5b, according to FIG. 2 is also provided with a pressure measuring point 10'. The values of pressure measuring point 10' must be compared with the values of pressure measuring point 12' which is also provided in air chamber 17, and results in the measuring value of 13'. In this manner, it is possible to independently regulate the air stream in venturi meter 5b or in the annular channel which is formed by both venturi meters 5a and 5b.

The oil burner of FIG. 3 is provided with three venturi meters 5a, 5b and 5c. As in FIG. 2, the smallest diameters of the venturi meters are provided with pressure measuring points 10,10' and 10". The values of these pressure measuring points have to be compared with the values of a common pressure measuring point 12 in air chamber 17, which result in the values 13,13' and 13". In accordance with these measurements, the air supply can be regulated. The size of the air entrance opening which is formed by venturi meters 5a and 5b can be adjusted by means of drum slide 15. The size of the ring slit which is formed by venturi meters 5b and 5c can be adjusted by moving venturi meter 5c. The adjustment is done by a rod 19 which extends through the rear wall of the burner.

In FIG. 4, a burner is shown with two venturi meters which are provided with two additional gas burner nozzles 20 in the range of the annular air exit channel. The nozzles are fed or supplied from a gas distribution ring 21 which is provided in air chamber 17. Because of the inventive arrangement of the air measurement with which it is possible to measure the amount of air which streams through the air measurement arrangement, the oil as well as the gas burner can be operated at an optimum. In place of gas nozzles 20, additional oil nozzles may also be provided.

In FIG. 5, a burner with one venturi meter is shown. A screen 22 is provided at the air entrance opening. Due to the screen, the air is made swirl free before entering the venturi meter. The burner nozzle is a combined oil, dust, or gas burner nozzle, whereby oil burner pipe 4 is surrounded by a gas or dust supply pipe 23. The oil burner pipe is preferably movable with respect to the dust or gas supply pipe, so that in the operating position "GAS," as shown in FIG. 6, a burning or scorching of the oil nozzle is avoided.

In FIG. 7, an oil burner is shown having additional air nozzles 24 at the air exit opening of venturi meter 5. A constant air stream is supplied through these air nozzles, while only the air which streams through the venturi meter is regulated. This measure permits a more exact measurement of the total amount of air.

In the oil burner shown in FIG. 8, the exit opening of venturi meter 5 extends into a cylindrical exit piece 8. This exit piece permits a concentration of the flame which is desirable at smaller installations.

While only a few embodiments of the present invention have been shown and described, it will be obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

Claims

What is claimed is:

1. An oil burner for a steam generator, comprising:

a burner pipe, having a nozzle mounted on its end, disposed through a front wall of the steam generator and extending through an opening in a rear wall of the generator and means mounting said pipe for axial movement;

an air chamber, disposed between the front and rear walls of the generator, for supplying air to said burner nozzle;

means for regulating the supply of air from said air chamber about said burner nozzle; including

a plurality of venturi air measurement devices, having different diameters and being concentrically and telescopically disposed about said burner pipe, and communicable with said air chamber, for supplying air from said air chamber to said burner nozzle and simultaneously measuring the air pressure and the quantity of air supplied to said burner nozzle through said venturi air measurement devices, and for providing a centrally-disposed air flow through one of said venturi air measurement devices about said burner pipe and at least one circular air flow through at least one of said other venturi air measurement devices from said air chamber to said burner nozzle about said burner pipe.

2. The oil burner as recited in claim 1, wherein said venturi air measurement devices include first and second truncated cones, each being co-axially joined to the smaller opening of the other of said cones, said first truncated cone being disposed within said air chamber and having its larger opening directed towards the rear wall of the generator, and wherein said means for regulating the quantity of air supply to said burner nozzle comprises a drum slide disposed about said first truncated cones of said venturi air measurement devices and an actuating rod coupled to said cylindrical drum slide, said rod moving said drum slide axially across an opening formed between the larger opening of said first truncated cone and the rear wall of the generator to regulate the quantity of air flowing thereinto.

3. The oil burner as recited in claim 2, further comprising air guide rings, disposed on the edges of said first truncated cones of said venturi air measurement devices about the air inlet openings thereof so as to form a plurality of radial air inlet openings about said burner pipe and cause a radial entrance of air into said venturi air measurement devices.

4. The oil burner as recited in claim 3, wherein said drum slide is disposed about one of said radial air inlet openings formed by said guide rings, and progressively closes off said radial air inlet opening as said drum slide is moved axially across said opening by said actuating rod, so as to progressively open and close said radial air inlet opening to control the air flow about said burner nozzle.

5. The oil burner as recited in claim 4, wherein at least one of said co-axially disposed venturi air measurement devices is axially movable with respect to said burner pipe.

6. The oil burner as recited in claim 4, further comprising at least one additional burner nozzle disposed in the air outlet opening of at least one of said venturi air measurement devices.

7. The oil burner as recited in claim 5, wherein the angle of inclination of said first truncated cones of said venturi air measurement devices with respect to the axis of said burner pipe is between 20.degree.-22.degree., and the angle of inclination of said second truncated cones of said venturi air measurement devices with respect to the axis of said burner pipe is between 5.degree.-15.degree. .