EP0103651B1 - Short tip for flame cutting or flame priming - Google Patents

Abstract

1. A round or flat tip for flame cutting or flame scarfing articles or the like, the tip having a feed duct (2 in Fig. 1 ; 2' in Fig. 2) for the cutting or flame oxygen and at least one ring, preferably two rings disposed symmetrically of the central axis or central plane of the feed duct (2 in Fig. 1 ; 2' in Fig. 2) or rows on both sides of heating mixing bores (7 in Fig. 1 ; 7' in Fig. 2), metering bores (10 and 6 in Fig. 1 ; 10' and 6' in Fig. 2) extending from distribution ducts (3 and 4 respectively in Fig. 1 ; 3' and 4' respectively in Fig. 2) for heating gas and heating oxygen, the latter ducts being annular or extending on each side of the tip respectively, the latter bores beginning with a metering cross-section and extending by way of a mixing cross-section into the heating mixing bores (7, 11 respectively in Fig. 1 ; 7', 11' in Fig. 2), characterized in that the feed duct has an entry part (14 in Fig. 1 ; 14' in Fig. 2) merging by way of a sharp abrupt and substantially transition free narrowing in a central part (15 in Fig. 1 ; 15' in Fig. 2) to a metering cross-section (15 in Fig. 1, 15' in Fig. 2) of from 1 to 4 mm in diameter or height, respectively, and of a reduced length of less than 10 mm, the central part merging into an exit part (16 in Fig. 1 ; 16' in Fig. 2) having a uniform (angle beta) or multistep widening to an exit width of from 2 to 6 mm.

Description

The invention relates to a round or flat short nozzle for flame cutting or flaming workpieces made of steel or the like with a feed channel for the cutting or flame oxygen and at least one, preferably two rings or rings arranged symmetrically to the central axis or central plane of the feed channel or rows of heating mixing holes on both sides , whereby dosing bores with a dosing cross-section depart from annular distribution channels for heating gas and heating oxygen and run on each side of the nozzle and open into the heating mixing bores with a mixing cross-section.

Nozzles of various types are already known, in which a round supply channel for the cutting oxygen is provided in a round design or, in a flat embodiment, the flame oxygen exits in the middle. With a round nozzle, it is known to arrange a central supply channel for the ring-shaped heating bores (DE-A-25 47 475). Such a round nozzle, as also in a flat embodiment, has to meet a wide variety of requirements, which, however, have so far been unsatisfactory. For example, in the case of a nozzle for cutting, a high cutting speed with a small kerf is desirable. The known nozzles are usually optimized in one direction or the other or aligned to specific operating conditions.

Basically, a large cross-section was provided for heavy cutting because of the required amounts of cutting oxygen, which must be supplied at a sufficiently high speed. On this basis, nozzles were developed in which the supply channel for the cutting oxygen in the sense of Laval nozzles is equipped with a constriction that gradually builds up and decreases again (DE-A-26 33 719). In another embodiment that has become known, the oxygen supply channel is narrowed by a gradual transition (US Pat. No. 3,788,558). This is to achieve a gas flow in which pressure loss is avoided as far as possible.

The invention is based on the object of making a short nozzle for the thermochemical machining of steel or the like available, which is improved with an optimal design of the heating system and in particular the feed channel for the cutting or flame oxygen while saving material and gas consumption, and one cheaper manufacturing allowed.

The invention consists in a short nozzle of the type mentioned in that the feed channel has an input section with a sharp, sudden, almost seamless narrowing in a central section to a metering cross section of 1 to 4 mm in diameter or height with a short length of less than 10 mm and has an adjoining exit section with a uniform or multi-stage expansion to an outlet of 2 to 6 mm.

This creates a pressure / speed conversion due to a sudden change in cross-section. The large shock or energy loss that occurs is largely compensated for by the low friction loss of the short nozzle compared to the friction loss in a laminar long bore.

An advantageous embodiment consists in that at least one ring or at least one row of heating mixing bores extends at an angle to the feed channel at an angle.

It is expediently provided that in the arrangement of two rings of heating mixing bores or two rows of heating mixing bores on each side, the outer ring or the outer rows are inclined and the inner ring or the inner rows are guided parallel to the feed channel. An advantageous embodiment consists in the fact that connecting bores with a metering cross-section run from the distribution channels in the region of the metering bores to the heating mixing bores of the adjacent ring or the adjacent row.

The external heating mixing bores advantageously run at an angle of 4 to 5 ° to the nozzle axis.

The total length of the nozzle body is about 30 mm.

Further advantageous and expedient details and further developments are characterized in the subclaims.

With this nozzle not only a remarkably cheap heating is achieved, but also an improved stability of the heating jet. First of all, this makes it possible to choose a large nozzle distance, which reduces wear and significantly increases the service life of the nozzle. During the cutting process, the nozzle enables flying cutting with a short heating time and a high cutting speed. That means not only a time saving, but additional. Measures such as iron powder, ignition wheels or preheating burners are superfluous, and the edge position is no longer a problem with the nozzle. With the flame, the quick heating-up time significantly increases the service life, since the nozzle is not exposed to heat radiation when heating for a longer period of time, and the entire flame process is well supported. The stable gas jet creates a very good surface of the workpiece when it is burned and ensures that there is a small material gap with a high one when flame cutting Cutting speed.

The nozzle according to the invention is to be explained in more detail below on the basis of exemplary embodiments with reference to the drawing, the same reference numbers relating to corresponding parts or features in the two figures.

• Figur 1 eine Düse in ihrer Ausführungsform zum Brennschneiden, teilweise im Schnitt ; und
• Figur 2 eine entsprechende Düse nach Fig. 1 in ihrer Ausführungsform zum Flämmen, ebenfalls teilweise im Schnitt.

The drawing shows:

• 1 shows a nozzle in its embodiment for flame cutting, partly in section; and
• Figure 2 shows a corresponding nozzle according to Fig. 1 in its embodiment for flame, also partially in section.

In Fig. 1, a short nozzle for cutting is shown. In the nozzle body 1, which has a basic body length L of 30 cm, a cutting oxygen supply channel 2 is provided in the center, which is surrounded by mixed fuel gas bores 11 running in parallel. Outside the fuel gas heating mixing bores 11, oxygen heating mixing bores 7 are arranged, which run at an angle a obliquely to the outlet end of the heating mixing bores 11 and emerge directly next to them. The oxygen heating mixing holes 7 run at an angle a of 4 ° to 5 ° to the nozzle axis. The heating mixing bores 7 have an annular distributor ring channel 4, into which a heating oxygen supply 5 opens, which is not shown in detail. Heating oxygen metering bores 6, which open into the actual oxygen heating mixing bore 7, depart from the heating oxygen distribution ring channel 4. The heating oxygen metering bore 6 has a diameter of approximately 1 mm, while the oxygen heating mixing bore has a diameter of 2.3 mm. For the fuel gas, an annular fuel gas distribution ring channel 3 is provided, into which a fuel gas supply 8, not shown, opens. A fuel gas connecting bore 9 runs obliquely from the fuel gas distributor ring channel 3 to the oxygen heating mixed bore 7 and opens into the latter at the upper end. This fuel gas connection bore 9 also has a diameter of 1 mm.

Fuel gas feeds 8 (not shown in detail) open into the annular fuel gas distributor ring channels 3. Thus, fuel gas can pass from the fuel gas distributor ring channels 3 through fuel gas metering bores 10 into the fuel gas heating mixing bores 11. The fuel gas metering holes 10 have a diameter of 1.3 mm. The fuel gas heating mixing bore 11, on the other hand, has a diameter of 2.3 mm, like the oxygen heating mixing bore. A heating oxygen connecting bore 12 runs from the heating oxygen distribution ring channel 4 to the fuel gas / heating mixing bore 11. The heating oxygen connecting bore 12 has a metering section 13 with a reduced cross section, which is approximately 0.5 mm. Thus, there is a mutual supply of heating oxygen to the fuel gas heating mixing hole and of fuel gas to the oxygen heating mixing hole, whereby in addition to the actual remixing after exiting from the oxygen heating mixing hole 7 and the fuel gas heating mixing hole 11, the fuel gas is premixed in a certain manner by the fuel gas small amounts of heating oxygen are supplied through the heating oxygen connecting bore 12, while fuel gas is also fed into the heating oxygen mixing bore 7 via the fuel gas connecting bore 9. In terms of construction, this is achieved in that the oxygen connecting bore 12, 13 and the fuel gas connecting bore 9 are located one behind the other in the view according to FIG.

The cutting oxygen supply channel 2 consists of an input section 14, a narrowed central section 15 and a conically widening output section 16. The input section 14 of the cutting oxygen supply channel 2 has a diameter of 5 mm, while the subsequent narrowed central section has a diameter of 2 mm. 6 via 3.25 mm. The outlet section 16 of the cutting oxygen feed channel 2 has an outlet diameter of 4.3 mm, the outlet bore expanding at an angle β to the central axis of the nozzle body of 7 °.

The nozzle designed for flame cutting achieves an optimally small kerf at a very high cutting speed. Due to the favorable heat development, which also enables a high cutting speed, an optimal slag flow is made possible, so that only comparatively small slag whiskers are formed, and the entire cutting surface is significantly improved. By increasing the nozzle spacing from the usual 60 mm to 120 mm, the life of the nozzles is significantly extended. On the other hand, a quick nozzle change is possible and thus easy maintenance. The nozzle, whose basic body length L of the nozzle body is 30 mm, requires a relatively small amount of material and can therefore also be regarded as inexpensive. The nozzle is characterized by low noise and also low consumption. When operating with propane at a pressure of 0.6 bar and hot oxygen of 2.6 bar, optimal results were achieved. By achieving these versatile advantages with a nozzle which, despite the high cutting speed, causes small kerfs, so that there is considerable material savings, the invention makes available a nozzle with unique optimization of the various requirements that are currently being put to flame cutting. The operating pressures are 10 to 16 bar for the cutting oxygen, about 2.5 bar for heating oxygen and 0.6 bar for the propane fuel gas.

In Fig. 2, a short nozzle for flaming is shown, which corresponds in principle to the nozzle of FIG. 1, as can be seen from the corresponding reference numerals. On the nozzle body 1 'is on the Exit end opposite side of a closure plate 20 mounted by brazing or other suitable means. For support, a ring 21 can also be attached to the base body 1 ', on which the closure plate 20 can also rest. A slot-shaped oxygen supply channel 2 'is formed in the middle, which runs perpendicular to the plane of the drawing and has an input section 14' which merges into a narrowed central section 15 'and which is followed by a conically widening output section 16'. This output section can also be designed to be gradually expanded. The entry section 14 'is not gripped by the closure plate 20, so that the entry section 14 is accessible for a flame oxygen supply, not shown. The closure plate 20 has a plurality of fuel gas feeds 8 'through which the fuel gas can pass into the transverse fuel gas distributor transverse channels 3'. Of these, fuel gas metering bores 10 'enter the fuel gas heating mixing bores 11', and in a corresponding manner, heating oxygen passes through the oxygen supply bores 5 'in the closure plate 20 into the transverse heating oxygen distribution transverse channels 4' and through heating oxygen metering bores 6 ' the oxygen heating mixing holes 7 '. Through a fuel gas connection hole 9 ', which leads from the fuel gas distribution channel 3' into the oxygen heating mixing hole 7 ', fuel gas enters the oxygen heating mixing hole 7' in a metered manner, while the heating oxygen connection hole 12 'heating oxygen from the heating oxygen distribution channel 4 'of the fuel gas heating mixing bore 11'. This provides the same basic structure for a short nozzle for flaming and also ensures a corresponding function. The nozzle body 1 'also has a length L of approximately 30 mm.

In the case of a short flame nozzle, advantageous results were achieved with a flame oxygen supply channel 2 ', the inlet section 14' of which consisted of a channel of 3 to 6 mm in height, the narrowed central section 15 'having a gap of 2 to 4 mm in height during which Exit gap of the output section 16 'was 3 to 5 mm.

With a nozzle designed in this way, significantly improved results were achieved in flame treatment, whereby - as mentioned at the beginning - the short heating-up time and the improved surface of the workpiece are particularly noteworthy.

Claims (15)

1. A round or flat tip for flame cutting or flame scarfing articles or the like, the tip having a feed duct (2 in Fig. 1 ; 2' in Fig. 2) for the cutting or flame oxygen and at least one ring, preferably two rings disposed symmetrically of the central axis or central plane of the feed duct (2 in Fig. 1 ; 2' in Fig. 2) or rows on both sides of heating mixing bores (7 in Fig. 1 ; 7' in Fig. 2), metering bores (10 and 6 in Fig. 1 ; 10' and 6' in Fig. 2) extending from distribution ducts (3 and 4 respectively in Fig. 1 ; 3' and 4' respectively in Fig. 2) for heating gas and heating oxygen, the latter ducts being annular or extending on each side of the tip respectively, the latter bores beginning with a metering cross-section and extending by way of a mixing cross-section into the heating mixing bores (7, 11 respectively in Fig. 1 ; 7', 11' in Fig. 2), characterised in that the feed duct has an entry part (14 in Fig. 1 ; 14' in Fig. 2) merging by way of a sharp abrupt and substantially transitionfree narrowing in a central part (15 in Fig. 1 ; 15' in Fig. 2) to a metering cross-section (15 in Fig. 1 ; 15' in Fig. 2) of from 1 to 4 mm in diameter or height, respectively, and of a reduced length of less than 10 mm, the central part merging into an exit part (16 in Fig. 1 ; 16' in Fig. 2) having a uniform (angle β) or multistep widening to an exit width of from 2 to 6 mm.

2. A tip according to claim 1, characterised in that at least one ring or at least one row on each side of heating mixing bores (7 in Fig. 1 ; 7' in Fig. 2) extends at an inclination (angle a) to the feed duct (2 in Fig. 1 ; 2' in Fig. 2).

3. A tip according to claim 1, characterised in that when two rings of heating mixing bores (7,11 in Fig. 1) or two rows per side of heating mixing bores (7', 11' in Fig. 2) are provided, the most outward ring or most outward rows extend inclinedly and the inner ring or inner rows extend parallel to the feed duct (2 in Fig. 1 ; 2' in Fig. 2).

4. A tip according to claim 3, characterised in that communicating bores (9, 12 in Fig. 1 ; 9', 12' in Fig. 2) extend with a metering cross-section from the distribution ducts (3, 4 in Fig. 1 ; 3', 4' in Fig. 2) near the metering bores (6,10 in Fig. 1 ; 6', 10' in Fig. 2) to the heating mixing bores (7, 11 respectively in Fig. 1 ; 7', 11' respectively in Fig. 2) of the adjacent ring or adjacent row respectively.

5. A tip according to any of claims 1-4, characterised in that the outer heating mixing bores (7 ; 7') extend at an angle (a) of from 4 to 5° to the tip axis.

6. A tip according to any of claims 1-5, characterised in that the metering bore (6, 6') for heating oxygen has a diameter of approximately 1 mm.

7. A tip according to any of claims 1-6, characterised in that the heating mixing bores (7, 11 ; 7', 11') have a diameter of 2.3 mm.

8. A tip according to any of claims 4-7, characterised in that the communicating bores (9 ; 9') starting from the heating gas distribution duct (3 ; 3' respectively) extend at an inclination to the outer heating mixing bore (7) and have a diameter of approximately 1 mm.

9. A tip according to any of claims 1-8, characterised in that the metering bores (10 ; 10') starting from the flame gas distribution duct (3 ; 3' respectively) have a diameter of approximately 1.3 mm.

10. A tip according to any of claims 4-9, characterised in that the communicating bores (12 ; 12') starting from the distribution duct (4, 4' respectively) for the heating oxygen have a bore part (13') with a metering diameter of 0.5 mm.

11. A tip according to any of claims 1-10, characterised in that the feed duct (2) for the cutting oxygen has a diameter of approximately 5 mm in the entry part (14), a diameter of from 1.8 to 2.6 mm in the following narrowed central part (15) and an exit diameter of 4.3 mm in the widening exit part (16).

12. A tip according to any of claims 1-10, characterised in that the flame oxygen feed duct (2') has a height of from 3 to 6 mm in the entry part (14'), a gap size of 2 to 4 mm in the narrowed central part (15') and an exit gap of 3-5 mm in the widening exit part (16').

13. A tip according to claim 11 or 12, characterised in that the exit part (16 ; 16') of the feed duct (2; 2' respectively) widens at an angle (β) of approximately 7° to the tip axis.

14. A tip according to any of claims 1-13, characterised in that the length (L) of the main body of the tip is approximately 30 mm.

15. A tip according to any of claims 1-14, characterised in that a closure plate (20) formed with feed bores (5', 8') closes the distribution ducts (3', 4') which extend on either side of the tip.

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