GB2089962A - Gas burner - Google Patents

Abstract

A gas burner consists of a chamber (1) contained wherein are fuel elements (2) provided with axial and radial outlet orifices (3) and (4). respectively. Adjacent fuel elements (2) are so arranged with respect to each other that their end faces (5) at the outlet orifices (3, 4) are located in different planes relative to the plane of the chamber (1). <IMAGE>

Description

SPECIFICATION Gas burner This invention relates to thermal engineering and particularly to gas burners, which can be utilized to advantage in heating, heat-treatment and melting furnaces of the iron and steel industry as well as in boilers of thermal power stations.

Being a fuel ranking second to none in terms of cost, natural gas has come into widespread industrial application. In certain cases, such as the melting and reheating of iron and steel, high temperature and economical burning of the gas are chief considerations.

A high-temperature gas flame is a practical possibility when either the path of combustion is shortened or the heat liberated per unit volume of the flame is increased. Both these ways require gas burners of optimum design and preheating of the air or gas. Unfortunately, the gas burners in use are of an inadequate design, preventing the implementation of efficient methods of combustion. Moreover, they are neither efficient nor reliable in service when use is made of cold or hot air, cannot operate in conjunction with recuperators, and fail to produce a luminous flame for speedy heating up of materials owing to radiation.

There is known a gas burner with a converging nozzle containing an axial fuel element with outlet orifices arranged in a checkered pattern. The fuel element extends beyond the end of the nozzle so that the gas mixes with air both at the outlet and outside of the nozzle (cf. USSR Inventor's Certificate No. 241,353, Cl. F 27 C 1/10, 1969).

The known gas burner permits the combustion of gas in a flow of hot air, producing a short luminous flame.

Yet, the known burner is incapable of meeting the requirements of special processes, such as in metallurgy, in point of the shape, luminosity, temperature, and gas content of the flame which all must vary from section to section thereof.

There is known another burner used mainly in steam and hot-water boilers which is the prototype of the present invention (cf. Maizels P.B., Vigdorchik D.Ya. "Gasogorelochnye Ustroistva," Publishers of Books on Construction, Moscow, 1964, p.200).

That burner incorporates a plurality of fuel elements contained in a chamber and provided with axial and radial orifices serving as gas outlets.

Its salient feature is that the air-to-gas ratio of the mixture admitted into the furnace is 1.05 to 1.1, provided that the pressure of the gas and of the air are of the same. As a result, the burner produces a transparent flame after the furnace lining has adequately warmed up.

However, the known gas burner also fails to meet the requirements referred to above, that is, it cannot be applied when carrying out special processes in point of the shape, and variable gas content of the flame from section to section thereof, luminosity and temperature, and does not provide for adequate intermixing of the gas and air.

The main object of the present invention is to provide a gas burner whrein the adjacent fuel elements are arranged with respect to each other so as to produce a short, luminous and shaped flame when the gas is being burnt in either a cold or hot air blast, to reduce the oxidizing property of the products of combustion and to increase their temperature.

The object should be attained due to the fact that in a gas burner comprising fuel elements which are contained in a chamber and are provided with axial as well as radial outlet orifices, the adjacent fuel elements are so arranged with respect to each other according to the invention that their end faces at the outlet orifices are located in different planes other than the plane on which the chamber is located.

A gas burner thus constructed ensures unobstructed outflow of the gas from each of the fuel elements into the flow of air so as to produce a flame of its own at each of the fuel elements.

Apart from that, a fuel element whose end face at the outlet orifices is located in a plane closer to that of the chamber than the end face at the outlet orifices of another fuel element will heat up the walls of this latter fuel element and, consequently, warm up the gas therein to a high temperature.

The hot gas issuing from the fuel element mixes with air and produces a short high-temperature flame which is luminous and contains less oxidizing products of combustion than ever before.

In addition to that, the disclosed burner improves the process of intermixing of the gas with air and intensifies the combustion of gas on the whole.

In accordance with the invention, the distance (1) between the end faces of adjacent fuel elements located in different planes is equal to between 0.3 and 12 times their diameter (d).

This arrangement is conducive to a short flame produced by the burner and improves the process of intermixing of the gas and air.

If the gas burner is made so that the distance (1 i) between the end faces of adjacent fuel elements located in different planes is less than 0.3 times the diameter, the temperature of combustion will be drastically reduced and the combustion will be an incomplete one, for no warming up of the gas in the fuel elements will take place.

On the other hand, if the distance (1 i) between the end faces of adjacent fuel elements located in different planes is greater than 12 times the diameter (d), fuel elements are likely to get fused on the high-temperature zone of flames.

It is expedient that the end faces of the fuel elements extend beyond the chamber of the gas burner through a distance (1 2) which is between 0.3 and 12 times their diameter (d).

This arrangement ensures that the gas burner produces a short luminous flame at a high temperature.

If the end faces of the fuel elements extend beyond the chamber of the gas burner through a distance (12) which is less than 0.3 times the diameter (d), the gas flow will lack the turbulence required in order to enable combustion to take place next to the outlet orifices (3, 4) of the fuel elements. This will prevent thorough mixing of the gas with air and result in a short flame.

Should the end faces of the fuel elements extend beyond the chamber of the gas burner through a distance (1 2) which is greater than 1 2 times the diameter (d), this may lead to the fusing of the fuel elements at the periphery of the chamber and failure of the gas burner.

The present invention will be best understood from the following description of a preferred embodiment which is illust,uted In conJunction with the accompanying drawings in which: Fig. 1 is a sectional elevation of the gas burner in accordance with the invention; Fig. 2 is a view similar to Fig. 1, showing the front elevation; Fig. 3 is a section on line Ill-Ill of Fig. 2; Fig. 4 is a view similar to Fig. 1, showing fuel elements which increase or decrease in length; Fig. 5 is a view similar to Fig. 1, illustrating the way the ends of fuel elements progressively increase in length in the direction from the walls ol the chamber to the centre line thereof;; Fig. 6 is a view similar to Fig. 1, illustrating the way the ends of fuel elements progressively increase in length in the direction from the centre line of the chamber to the walls thereof.

The disclosed gas burner consists of a chamber (1) containing fuel elements having axial and radial outlet orifices 3 and 4, respectively.

Adjacent fuel elements 2 are arranged with respect to each other so that their end faces 5 at the outlet orifices 3, 4 are located in different planes relative to the plane of the chamber 1. The distance 1 t between the end face of the adjacent fuel elements 2 which are located in different planes is between 0.3 and 1 2 times the diameter of the fuel elements. In addition, the end faces 5 oi the fuel elements 2 extend beyond the chamber 1 through a distance which is 0.3 to 12 times the diameter d.

By selecting a suitable arrangement of the fuel elements 2 in the chamber 1 it is feasible to control the shape, temperature, and luminosity of the frame as well as the composition of gases inside same. So, for example, if the fuel elements 2 progressively increase or decrease in length as illustrated in Fig. 4, the flame produced will be a luminous one characterized by uniform composition and temperature irrespectively of the temperature of the air which can be cold or hot.

This uniformity will exist in the sections of the flame parallel to a plane through the extreme points of the end faces of the fuel elements 2.

A progressive lengthening of the fuel elements 2 so that the shortest elements are at the walls of the chamber 1 and the longest one is at the centre line thereof as illustrated in Fig. 5 creates an advanced high-temperature zone of high luminosity at the centre of the flame produced by the burner. On the other hand, the lengthening of the fuel elements 2 in the opposite direction as shown in Fig. 6 is conducive to a flame in which luminosity is at its maximum in the boundary zones. Not excluded is the possibility of arranging the fuel elements 2 in more intricate patterns to obtain flames of various shape. The fuel elements 2 can be adjusted for length by being shifted in the chamber 1. This implies that the shape and dimensions of the flame produced by the burner as well as the relative disposition of zones inside same can be controlled when the burner is in operation.

The exit section of the chamber 1 can be given any shape (rectangular, cruciform, U- or T-shape, oval, triangular, polygonal, and more intricate) so as to adapt the disclosed burner to furnaces of any configuration.

The disclosed gas burner operates on the following lines. Cold or hot air is admitted into the chamber 1 while hot gas is introduced into the fuel elements 2. The combustible gas issuing thereform by way of the axial and radial orifices 3 and 4, respectivley, mixes up with the air and is inflamed. The jets of the outflowing gas induce turbulence at each of the outlet orifices which facilitates the advance of the zone of combustion towards thereof. The fact that the end faces 5 of the adjacent fuel elements 2 are located in different planes permits unobstructed progress of the gas jets through the air stream so that each of them is turned into a flame. Moreover, each of the fuel elements which is shorter than the adjacent ones heats up their walls, warming up the gas passed therethrough to a high temperature.The hot gas issuing out of the orifices 3 and 4 of the fuel elements 2 mixes with the air and produces a short high-temperature flame of high luminosity.

The products of combustion formed in this case are less oxidizing than with the known gas burners.

The disclosed gas burner is instrumental in producing a short luminous flame of various shapes, using hot or cold air. It also reduces the oxidizing ability of the products of combustion which is a factor ensuring normal operation of cupolas, especially when steel scrap is a component of the charge. The short luminous flame produced by the disclosed burner operating on a mixture of natural gas with cold or hot air intensifies the heat transfer by radiation, increases the thermal efficiency of plant, reduces the wear of lining and the size of furnaces.

The disclosed burner poses no problems at starting, and ensures reliable and safe operation without blowouts. The turbulence of the mixture of gas and air which is set up at each of the fuel elements provides for rapid propagation of the flame at starting. This is a factor stabilizing the process of combustion, reducing the length of the flame, and increasing the temperature of combustion. The disclosed gas burner can operate at any pressure of the gas air and at an air-to-gas ratio greater and lesser than unity. The gas to be used can be of any composition such as natural gas, acetylene, propane, butane, casing-head gas, producer gas, coke-oven gas and various gas mixtures. The air can be enriched with oxygen or pure oxygen can be used as the oxidizer.

Claims (4)

1. A gas burner comprising fuel elements which are contained in a chamber and provided with axial and radial outlet orifices wherein adjacent fuel elements are so arranged with resepect to each other that their end faces at the outlet orifices are located in different planes relative to the plane of the chamber.

2. A gas burner as claimed in claim 1, wherein the distance (1 i) between the end faces of adjacent fuel elements which are located in different planes is between 0.3 and 12 times the diameter (d) of the fuel elements.

3. A gas burner as claimed in claim 1, wherein the end faces of the fuel elements extend beyond the chamber through a distance which is between 0.3 and 12 times the diameter (d).

4. A gas burner as claimed in any of the above claims and substantially as hereinabove described with reference to and as shown in the accompanying drawings.