WO1986003573A1

WO1986003573A1 - Adjustable burner nozzle

Info

Publication number: WO1986003573A1
Application number: PCT/US1985/002421
Authority: WO
Inventors: Raymond Helmuth Miller
Original assignee: Union Carbide Corporation
Priority date: 1984-12-12
Filing date: 1985-12-11
Publication date: 1986-06-19
Also published as: ES296368U; EP0204825A1; JPS62501439A; ES296368Y; BR8507116A

Abstract

An adjustable burner nozzle having improved heat dissipation characteristics comprising a nozzle passage through a curved piece matingly fitted against a correspondingly curved burner passage wall to form a large and constant conductive heat transfer area.

Description

ADJUSTABLE BURNER NOZZLE

Technical Field

This invention relates generally to burner nozzles which can be adjusted to alter the direction of flow of fluid passing through the nozzle and specifically is. an improved adjustable burner nozzle which enables more rapid heat dissipation from the nozzle. The improved nozzle features an infinitely adjustable angle resulting in improved temperature distribution.

Background Art

Burners are used extensively in industrial and other applications to produce heat in a furnace or other such apparatus. Generally fuel and oxidant flow through the burner body, either separately or as a mixture, and are injected, through a nozzle, into a furnace zone wherein they combust to produce heat. Often the nozzle employed is an adjustable nozzle which can be adjusted to alter the direction of flow of the fluid so as to change the direction or shape of the resulting flame.

Generally an adjustable burner nozzle comprises a threaded piece with an angled passage through it. The threaded piece is screwed into a burner passage at the discharge end of the burner. As the threaded piece is rotated through a 360 degree turn, the angled passage changes its flow direction. Thus one attains the desired fluid flow direction by rotating the threaded piece to the desired point. Such threaded pieces may also be removed for cleaning or replacement, or to change the angle of the fluid flow with respect to the burner face. In the latter case the threaded piece is removed and replaced with another threaded piece having a passage through it at the desired angle.

Temperatures at the burner face where the nozzle is located are quite high, generally exceeding 2500^βF, and much of this heat is radiated to the burner face and the nozzle. It is imperative that the nozzle be effectively cooled because the greater the temperature at which the nozzle is operated, the shorter the effective life of the nozzle. Furthermore, high heat is especially deleterious for an adjustable nozzle because the high heat may cause the threaded area to scale or otherwise seize thus rendering the nozzle, non-adjustable and unremovable. The problem is exacerbated by the fact that cooling water cannot be piped as close to an adjustable nozzle as it can be to a ixed nozzle because the cooling water passage must not interfere with the threaded seat.

A particular problem with the conventionally employed adjustable nozzle is that the contact between the threaded nozzle piece and the threaded seat is necessarily not good unless the nozzle is fully screwed into the seat and set there with relatively high or tight tension. However this situation occurs only at one nozzle setting. All other nozzle settings around the 360 degree arc must be at loose tension. This is troublesome because the loose tension and resulting poor contact between the threaded nozzle and the threaded seat results in an impediment to heat transfer, i.e. heat dissipation from the nozzle to the burner body and to the cooling fluid.

It is therefore desirable to have an adjustable burner nozzle which can dissipate heat at an improved rate over that rate possible with conventionally employed adjustable burner nozzles.

Accordingly it is an object of this invention to provide an improved adjustable burner nozzle.

It is another object of this invention to provide an improved adjustable burner nozzle which can dissipate heat at a faster rate than that rate possible with heretofore known adjustable burner nozzles.

Summary of the Invention

The above and other objects which will become apparent to one skilled in the art upon a reading of this disclosure are attained by the present invention which comprises:

An adjustable burner nozzle having improved heat transfer comprising:

(a) a burner head having a burner passage communicating with the burner discharge end, said burner passage having a smooth concave portion recessed from the burner discharge end;

(b) a spherical piece having a smooth spherical surface and having a nozzle passage completely therethrough, moveably seated within said burner passage and in full surface contact with said smooth concave portion; and (c) means to secure said spherical piece In full surface contact with said smooth concave portion.

As used herein, the term "full surface contact" means the positioning of two mated surfaces together in mated relation with enough space between the surfaces to.allow relatively unhindered movement of one surface relative to the other, i.e. the space between the mated surfaces does not appreciably exceed the minimum space required for relatively unhindered movement.

Brief Description Of The Drawings

Figure 1 is an axial cross-sectional representation of one_. referred embodiment of the adjustable burner nozzle of this invention. . Figure 2 is a view of the Figure 1 embodiment as viewed from the furnace zone.

Detailed Description

The^*adjustable burner nozzle of this invention will be described in detail with reference to the drawings.

Through burner head portion 1 passes burner passage 2 which communicates with burner discharge end 3 so as to discharge fluid passing through burner passage 2 into furnace zone 4. Burner passage 2 is also connected to a source of fluid such as by manifold 5. The fluid for passage through burner passage 2 may be oxidant such as air, enriched air, or oxygen, or it may be fuel such as natural gas or coke oven gas, or it may be a mixture of fuel and oxidant. Burner passage 2 is generally cylindrical although it may be of any effective geometry.

Recessed from burner discharge end 3, the walls of burner passage 2 form smooth concave portion 6 which is shaped to matingly receive a spherical object.

Preferably the cross-sectional area of burner passage 2 increases upstream of concave portion 6 such as is shown by portion 7 of burner passage 2.

This enlarged portion 7 is advantageously employed to increase the range of positions to which the nozzle may be adjusted and thus increase the flexibility and utility of the invention.

Within burner passage 2 is seated spherical piece 8 having a smooth spherical surface. In the preferred embodiment of Figure 1, spherical piece 8 is a complete sphere. Sphere 8 is not fixed in position but rather is free to move in all rotational directions. Sphere 8 is seated in full surface contact with smooth, concave surface portion 6. Sphere 8 and the other burner parts are generally made of copper or copper-nickel alloys. Copper is the preferred material of construction.

Completely through sphere 8 there passes nozzle passage 9 which is generally of circular or oval cross-section but which may have any effective geometry. In practice, a cross-sectional area of

2 about 0.072 in. for nozzle passage 9 has been usefully employed. In order for the nozzle to be directional, the length of the nozzle passage must significantly exceed its cross-sectional widest diameter. Preferably the nozzle passage length is at least three times greater than the nozzle passage diameter at its widest point when the nozzle passage has a constant cross-section through the spherical piece. Nozzle passage 9 may also be converging or diverging.

Since the fluid passing through burner passage 2 is generally at relatively high pressure, a means to secure sphere 8 in surface contact with concave portion 6 is of importance. Otherwise the high pressure fluid may cause axial displacement of sphere 8 from concave portion 6. Figure 1 illustrates locking ring 10 which is a preferred such securing means. As shown in Figure 1, locking ring 10 is shaped to mate with sphere 8 and is also mated by means of a thread to burner head 1. Locking ring 10 is screwed into place by placing wrench face pins into wrench receivers 11 and turning until sphere 8 is secured in surface contact with concave portion 6.

To adjust the direction at which fluid is injected into furnace zone 4, locking ring 10 is loosened, sphere 8 is rotated to the desired position,and locking ring 10 is retightened. To remove sphere 8, such as for servicing or replacement, locking ring 10 is screwed out of burner head 1 and sphere 8 is simply taken out. Thus the burner nozzle of this invention may be adjusted or serviced with relative ease.

The benefits of this invention are attained by the high contact area between sphere 8 and burner head 1 which is cooled during combustion operation, generally by flow of cooling water. Because this contact area remains high and constant irrespective of the position of sphere 8, heat is transfered at a relatively high rate from the nozzle to the coolant. Thus the nozzle is operated at a temperature lower than that at which conventional adjustable burner nozzles may be operated. This increases the working life of the nozzle and markedly reduces the chance that the nozzle may seize in place.

In operation, fuel, oxidant or a mixture thereof passes through burner passage 2 and through nozzle passage 9. The orientation of nozzle passage 9 determines the angle and direction at which the fluid is injected into furnace zone 4. Within furnace zone 4 the fluid combusts and the resulting combustion radiates heat to the nozzle area. The heat radiated to sphere 8 is conducted through the entire mated area of the spherical surface and concave surface 6 from sphere 8 to burner head 1. The burner head is in turn cooled generally by flow of cooling water through it.

Another benefit of this invention is the ability to change not only the direction of the fluid flow, but also the angle of the fluid flow relative to the burner face, without need to change the nozzle. Conventional adjustable burner nozzles have a fixed angle of injection, for example 30 degrees. In order to inject fluid into the furnace zone at 15 degrees, one had to remove the 30 degree nozzle and replace it with the 15 degree nozzle. However, with the nozzle of this invention one merely rotates sphere 8 to the desired angle, such as by moving sphere 8 to move nozzle passage 9 along axis line A-A in Figure 2. Directional changes are made by moving sphere 8 so that nozzle passage 9 moves in a circular manner as observed from the vantage point of furnace zone 4. Changes in both direction and angle of fluid flow can be made by adjusting sphere 8 so that nozzle passage 9 is seen to move in both a circular and transverse direction. It is thus seen that the burner nozzle of this invention may be easily adjusted to a great many settings. The beneficial heat transfer characteristics of the burner nozzle of this invention are not detrimentally affected at any of these settings. The nozzle of this invention runs cooler than conventional adjustable nozzles no matter what the setting.

As was mentioned earlier, the preferred embodiment of spherical piece 8 is as a complete sphere as is illustrated in the drawings. However, it can be appreciated that spherical piece 8 need not have a completely spherical surface. A spherical surface is required only so far as is necessary to mate in full surface contact with concave portion 6 and to rotate in such a way as to achieve the desired adjustability.

The following example serves to further illustrate the advantages attainable by use of the adjustable burner nozzle of this invention. The example is presented for illustrative and comparative purposes and is not intended to be limiting.

EXAMPLE 1 The most severe heat dissipation conditions for a burner nozzle exist when the furnace is at an elevated temperature but there is no flow of fuel or oxidant through the burner. These conditions exist when the furnace zone has reached the desired temperature and no more heat is needed, or when the furnace is shut down. In these situations the temperature in the furnace zone remains high and considerable heat is radiated to the burner nozzle, but there is no flow of fluid through the nozzle to remove heat. The burner nozzle of this invention and, for comparative purposes, a conventional adjustable burner nozzle were tested for heat dissipation under such severe no-flow conditions.

A water-cooled burner having a central fuel tube and eight oxidant passages equidistant from each other and spaced radially from the fuel tube., was employed. Two oxidant passages were each outfitted with an adjustable burner nozzle of this invention of a design substantially similar to that shown in the drawings. The six other oxidant passages were outfitted with conventional adjustable burner nozzles having a threaded seat. The furnace was brought to a temperature^' of 2320°F and held constant with a water in temperature of 57°F. The water out temperature with a water flowrate of 2.0 gallons per minute was 73°F when a steady state temperature was achieved in each of the eight burner nozzles. The steady state temperature of the two burner nozzles of this invention was 320^βF while the steady state temperature of the conventional burner nozzles was 420^βF. Thus the burner nozzles of this invention under comparable severe conditions operated at a temperature 100°F less, or 24 percent less, than the temperature at which conventional adjustable burner nozzles operated.

The procedure described above was repeated except that the- furnace temperature was only 2140°F. At this furnace temperature the burner nozzles of this invention operated at a temperature 22 percent lower than the conventional burner nozzles, thus further demonstrating the advantage attainable by the invention.

Claims

1. An adjustable burner nozzle having improved heat transfer comprising:

(b) a spherical piece having a smooth spherical surface and having a nozzle passage completely therethrough, moveably seated within said burner passage and in full surface contact with said smooth concave portion; and

(c) means to secure said spherical piece in full surface contact with said smooth concave portion.

2. The burner nozzle of claim 1 wherein said spherical piece is a complete sphere.

3. The burner nozzle of claim 1 wherein said nozzle passage has a length at least three times its diameter at its widest point.

4. The burner nozzle of claim 1 wherein said nozzle passage has a constant cross-section through the spherical piece.

5. The burner nozzle of claim 1 wherein said burner passage widens in cross-sectional area upstream of said concave portion.

6. The burner nozzle of claim 1 wherein said securing means is a locking ring.

7. The burner nozzle of claim 1 wherein said spherical piece is constructed of copper.