Burner for liquid fuels.

p0001The invention relates to a burner for the combustion of liquid fuel, particularly light fuel oil,<ul><li>with an inner housing, which surrounds a fuel line and in which primary combustion air is conveyed,</li><li>at least partly surrounding the inner housing with an outer housing in which secondary combustion air can be conveyed,</li><li>with a housing opening of the inner housing in the region of a nozzle head arranged at the end of the fuel conduit,</li><li>wherein the nozzle head with a fuel-Zerstäubungskegel be generated, in which the primary and secondary combustion air are introduced into it,</li><li>with an opposing openings in the outer and / or inner housing movable cover element to change the cross-section of the openings, which is connected to a supply of the quantity of fuel to the fuel conduit controlled valve.</li></ul>

p0002It is known from DE-PS 27 29 321. burner whose fuel feed line terminates in a nozzle head. Line and nozzle are as "lance" movable in a housing. The diffuser extends into a neck, having the openings. Through the line of heating oil is supplied to the-When it technically difficult continues to serve from the nozzle in the form of a vortex at stoichiometric burners the manner of ignition, such as with an ignition electrode. Only a "rich" mixture, ie a mixture with an oil surplus is easy to ignite.

p0003In the known burners occurs but such an ignitable mixture practically at any point in the combustion zones, so that the ignition with the ignition electrodes is difficult. Other igniters, ignition lances in particular, are known but not optimal to use in the description and in continuous operation.

p0004The aforementioned difficulties of the ignition electrodes must therefore be removed to provide a burner whose firing is easy and secure, the benefits of controlling the intake air and the fuel supply is to be maintained.

p0005To this end it is proposed that an entity belonging to an igniter ignition electrode should terminate in the outer surface of the spray cone in which still has the spray-air mixture significantly superstoichiometric, easily ignitable fuel fraction to air. The inventive solution is particularly therefore achieved, since the end of the ignition electrode is arranged at the point where a "fat" and therefore easily combustible mixture is present, without causing the rest of the composition and the operation of the fuel-air mixture must be changed.

p0006In an advantageous embodiment of the invention is fixed to the outer casing an adjustment head, in the conical front part slots are incorporated. Between the inner housing and adjustment head, an adjustable annular piston is fitted, which is connected to the piston rod. To the adjustable annular piston is arranged for adjusting head towards a sealing ring. The ring piston is preferably so long that it completely closes the slots in the forward position and completely frees in the retracted position. By changing the adjustable ring piston, the air supply can be controlled. Characterized in that the ignition electrode and the fuel line are arranged displaceably in a support device with the forwardly disposed nozzle head finer votes with respect to ignition and air supply are still possible.

p0007The invention will be explained in more detail below using an embodiment. Show it<dl id="dl0001"><dt>figure 1</dt><dd>a longitudinal section through a fuel oil burner;</dd><dt>figure 2</dt><dd>a valve for adjusting the amount of fuel supply for the aforementioned burner;</dd><dt>figure 3</dt><dd>the front portion of another Heizölbren ners of the same basic design as Figure 1;</dd><dt>figure 4</dt><dd>a fuel oil burner diagram.</dd></dl>

p00081 shows a longitudinal section through a fuel oil burner, which is equipped with a conventional atomizing nozzle head. 1 Such conventional atomising operating under oil pressure, for example, the book by Niepenberg, industrial oil furnaces; Publisher Head, Stuttgart, 2nd edition, refer 1973. The nozzle head 1 forms the end of a fuel feed line 8. The feed line 8 extends centrally fuel within an inner casing 7. The inner casing 7 has a cylindrical wall that tapers to the front part of the burner is stepped. The projecting from the inner housing 7 fuel line 8 is supported in a supporting device 20th The oil supply is switched on and issuable via a solenoid valve 18th The line 8 continues through those referred to in the drawing connection point A in FIG. 2

p0009As is well known, a Zerstäubungskegel 16 produced from the finest fuel particles with the nozzle head. 1

p0010In the front area the inner housing 7 terminates in an opening 9. There, the interior housing has on its inner side, already arranged in the outer edge of the spray cone 16, the swirl generator 10, consisting of small, transversely placed guide surfaces, as shown in FIG. 1 At the rear part of the inner housing 7, a nozzle 12 is provided for the supply of primary air. The primary air 9 is guided within the inner housing 7 up to the region of the opening and in a by means of swirl elements 10 brought vortex formation.

p0011In the supporting device 20 also has a line 3.1 for an ignition electrode 3 is held, the angled ends of the line 3.1 in front of the nozzle 1; at its other end it projects as well as the Brennstoffleitung 8 from the Innengehäuse 7 out and is in a known manner with a Hochspannungsquelle (not shown) and switched.

p0012The front part of the inner casing 7 encloses an outer casing 14 with a conical front part 14.1. Abschlußwandungen at 21, which limit the outer housing 14 to the front and leaving an opening 39, an adjustment head 5 is fixed with a likewise conical front part 5.1. Via a nozzle 15 secondary air is introduced into the outer housing fourteenth

p0013In the conical front part 5.1 slots 19 are introduced. Intermediate adjustment head 5 and the inner casing 7 an adjustable, sliding annular piston 2 is fitted, which is sealed via a sealing ring 6 for adjustment head 5 back. This annular piston 2 is so wide that 19 he can either close completely and open the slots, so that the secondary air 15 doses accordingly can be introduced into the region of the swirl 11th The slots 19 may also be inclined milled into the adjustment head 5, so that the run through the slots airflow to swirl generated by the swirl devices 10 and amplified 11th

p0014The annular piston 2 is connected via a (diagrammatically shown) linkage 32 with a rod piston 31 associated to a fuel valve 30 (see FIG. FIG. 2). The fuel valve 30 has a cylindrical housing 33 which is closed at its front end with a closure 34 and at its rear end with a closure 35th Both closures 34 and 35 are simultaneously provided via radial holes as an oil inlet 34 'or as an oil outlet 35'. The inlet 34 'is provided with a corresponding oil pressure line (not shown) and the oil outlet 35' to the line 8 of FIG. 1 connected (see. Connection point A).

p0015The housing 33 carries on its inner side a projecting flange 36, which is torus-shaped and in cross section has the shape of a trapezium converging inwardly. The flange is tangent with its inner surface 37, the outer side of the rod piston 31. The latter carries at its free end a wedge-shaped, protruding to the piston interior groove 38. The wedge angle of the groove is about 2-10 °. This groove 38 is each of the the rod piston 31 surrounding flange 36 is not closed, so that the pressurized oil in a corresponding position of the rod piston 31 beginning with zero quantity can flow to a greater amount per unit time, so that the space 39 in the space 40 can pass within the cylindrical housing 33 and from there to the oil outlet 35 '.

p0016By appropriate adjustment of the secondary air supply can be the stoichiometric amount of air required for the respective oil, precisely adjusted.

p0017As is apparent from Figure 1, the ignition electrode 3 and the fuel line 8 to the nozzle 1 can be adjusted on the support means 20 against each other. Such adjustment is not normally provided during operation. However, the adjustment can then be used, for example, if at the beginning of the burner setting a specific ignition timing is required or when to change the quality and composition or other parameters of the liquid fuel.

p0018In Figure 3, a front portion of another fuel oil burner is shown with the same basic design. In an inner housing 7, the fuel supply line 8 is arranged adjustably on the support means 20th Likewise, the ignition electrode can be adjusted 3. The nozzle 1 can therefore be adjusted relative both to the housing 7, the twister 10 and the ignition electrode 3rd The outer housing 14 is of a slightly different shape. Again, the annular piston 2 with the rod piston 31 slidably along.

p0019The <u>function</u> the apparatus shown in Figures 1 and 3 is as follows: About the valve 30 is controlled to the nozzle head 1 through the fuel feed line 8 the fuel oil supply. According to the supplied amount of fuel oil, depending on the opening of the gap of the groove 38, the supply air according to the parameters and conditions of stoichiometry by adjusting the primary air and secondary air is controlled. The used coming known nozzle 1 atomizes a dependent of the nozzle exit pressure heating oil, which gives a Zerstäubungskegel 16 having an outer surface 17th The nozzle head is surrounded by a twister 10 that causes the primary air into a vortex, which accommodates the fine oil droplets and into an eddy. This vortex is reinforced with additional crushing of the oil droplets upon addition of secondary air.

p0020It is essential that immediately after leaving, but after initial supervention the primary air an ignitable spray-air mixture is present, it is ensured that the ignition electrode 3 ends in the region of the outer surface of the spray cone 16, in which the Sprühstrahl- air mixture still has a considerably more than stoichiometric, easily ignitable fuel fraction to air. The burning and swirling fuel-air mixture, which does not burn first completely is further burned during the continuation and vertebral stabilization via the secondary air supply 15, the exact stoichiometric ratios by the movement of the annular piston 2 and thus the opening of the slots 19 regulated is. By making the distances between the end of the inner housing and inner side and outer side of the end wall 21 and annular piston 2 can be changed, also the flame length and width can be influenced.

p0021Information on the amounts of each to be set is the graph of Fig 4, which is explained as follows.: On the X-axis of the plunger opening, ie adjustment of the piston 31 is of a zero point indicated. In accordance with the oil pressure is the continuous amount directly proportional to the piston displacement. While the upper curves show this relationship in an oil nozzle type UMO 105, show the lower curves in the connection of a nozzle of the type UMO 108. At the same time provide the information in WS (mm water column) the required air pressure. These are arbitrary parameters in a particular embodiment. It is found that the principle of the invention is particularly usable for burners with a large power generation.