EP1423643B1 - Flame cutter with a multi-functional burner head - Google Patents

Abstract

In order to provide a flame cutter which can be used in a flexible manner, especially in a flame cutter machine with simple and compact nozzles which are easy to maintain, which can be produced in a low-cost manner and wherein the storage complexity of the working parts is reduced, the cutting nozzle connection is provided with a bore hole (30) with an inner thread for sealingly receiving a cutting nozzle provided with an outer thread, and with a radial peripheral sealing surface (31) for sealingly receiving a cutting nozzle with a sealing ring disposed on said sealing surface (31).

Description

The present invention relates to a cutting torch having a central axis having a burner head, to which a cutting nozzle with axial cutting oxygen line is cap-like embraced by a axial through-bore heating nozzle, wherein the burner head has a cutting nozzle connection, at which the upstream, upper End of the cutting nozzle is received sealingly to the outside, and is coaxially surrounded by an annular gap-shaped heating nozzle connection, where the upstream, upper end of the heating nozzle is sealed to the outside.

Such a cutting torch is from the DE-T2 690 03 588 known. It discloses a cutting torch having a cutting head to which an axial oxygen conduit cutting nozzle and a heating nozzle having an axial through-bore and embracing the cutting nozzle are secured. For this purpose, the heating nozzle and the cutting nozzle are provided with transverse end surfaces which correspond to corresponding transverse end surfaces of the burner head and which are pulled against each other by means of a cap nut attached to the burner head, which is supported on an outer collar of the heating nozzle, so that a sealing metallic compound of respective transverse end faces to the outside results.

In the known cutting torch, the cutting nozzle is designed as a so-called slot nozzle. This is formed of a piece of metal having an outer frusto-conical shape with a wide upstream end and a narrower downstream end. The axial cutting oxygen line extends from the top to the nozzle exit. At the outer periphery, the cutting nozzle has a series of radial ribs (longitudinal slots) formed by longitudinal milling in the metal body and extending from the downstream end of the cutting nozzle to an outer collar provided on the upstream side extend, with which the cutting nozzle rests on a radial inner recess in the inner bore of the heating nozzle.

The heating nozzle is formed by a solid part with an inner bore conically tapering towards the downstream end. The inner bore has in its upper region the mentioned radial inner recess. The conical part of the inner bore, which begins downstream thereof, is held somewhat narrower than the envelope of the cutting nozzle ribs, so that it can be fixed by friction in the heating nozzle by being pressed in from above. In this case, the axial stop position results from the support of outer collar and inner recess.

The production of such, conical contact surfaces in heating and cutting nozzle requires a lot of effort to maintain the necessary dimensional accuracy.

In addition, the use of the known cutting torch is set to a short working distance between the nozzle and workpiece surface in the range of 5 to 7 mm because of the taper of the nozzle.

During operation of the cutting torch, soiling occurs, in particular the cutting oxygen line, which leads to a loss of performance. Therefore, a regular cleaning is required, in which the nozzles must be completely disassembled. This has a detrimental effect on the fit of the conical contact surfaces of the heating nozzle and the cutting nozzle and can also lead to damage to the nozzles. Since the cutting nozzle is subject to greater wear, it would also be desirable to be able to replace them separately from the heating nozzle.

In addition, depending on the thickness of the workpiece to be cut and the cutting parameters, the use of a slow burning or a fast burning fuel gas is necessary. In the known cutting torch a selection of different cutting nozzles and matched heating nozzles must be available for this purpose, which is associated with a corresponding effort for storage and the change of different nozzles.

Although the known cutting torch has a compact construction meadow; however, it is designed solely for use with nozzles having a transverse sealing surface corresponding to the respective transverse sealing surfaces of the burner head.

There are also cutting torch known (eg CH-316957-A are known), in which the cutting nozzle and the heating nozzle are held by means of screw on the burner head.

The present invention is therefore an object of the invention to provide a flexible cutting torch - especially for a flame cutting machine - with simple, compact design of the nozzles, which is associated with easier maintenance, easier maintenance and cost-effective production, and in addition to the cost of the Warehousing of wearing parts is reduced.

This object is achieved on the basis of a cutting torch with the features mentioned in the present invention in that the cutting nozzle connection has a first bore with an inner wall, which inner wall with an internal thread and with a first radially encircling, metallic sealing surface for the sealing receiving one with external thread provided and abutting the first sealing surface cutting nozzle, and is provided with a second radially encircling sealing surface for sealingly receiving a cutting nozzle with a voltage applied to the second sealing surface sealing ring.

The burner head according to the invention thus has two different connections for the cutting nozzle. The ports each include a first bore (hereinafter also referred to as a "cutting nozzle receptacle") into which the upper end of the cutting nozzle extends.

At least two different elements are provided for making the connection with a cutting nozzle. One of the elements is an internal thread, which corresponds to an external thread of the cutting nozzle, wherein usually produces a seal to the outside by the contact force generated during screwing between abutting contact surfaces becomes. The other element is a radially encircling sealing surface, which forms a tight connection with a sealing ring of the cutting nozzle.

Thereby, the burner head can be used both for such cutting nozzles, which are provided at its upper end with an external thread as well as for such cutting nozzles, which have at their upper end a sealing ring (O-ring). In that regard, the burner head is multifunctional, which also contributes to reduced storage of the cutting nozzles and, consequently, lower manufacturing costs.

In addition to this, a particularly preferred embodiment of the cutting torch according to the invention, the heating nozzle connection to a second bore having an inner wall which is provided with an internal thread and a first radial metallic sealing surface for sealingly receiving a male thread and applied to the first sealing surface heating nozzle wherein the inner wall is provided with a second radially encircling sealing surface for the sealing receiving a heating nozzle with a voltage applied to the second sealing surface sealing ring.

In this embodiment, for the sealing support of the heating nozzle on the burner head, the same advantageous effects with respect to the flexibility of the burner head insert, as previously explained for the cutting nozzle.

It has proven particularly useful to provide the outer jacket of the cutting nozzle at the upper end with a sealing ring which bears sealingly against the inner wall of the first bore.

By means of the sealing ring, the cutting oxygen line is sealed to the outside and at the same time the cutting nozzle is radially fixed in the cutting nozzle holder. The cutting nozzle is withdrawn from the cutting nozzle receptacle in the direction of the longitudinal axis with elastic deformation of the sealing ring, and vice versa - the upper end of the cutting nozzle is fixed by axial insertion into the cutting nozzle receptacle. This type of fixation of the cutting nozzle requires little effort when changing the nozzle and it is also achieved in comparison with a metallic seal improved tightness.

The sealing ring is usually a fitting on the outer shell or the same inserted in an annular groove ring of elastic material.

A further improvement results when the cutting nozzle is held in the first bore with axial play. The cutting nozzle is only radially fixed in the first bore, while dispensing with an axial stop position in the direction of the central axis. Due to the axial play dimensional tolerances are intercepted in the length of the cutting nozzle, so that they neither have an influence on the outer dimensions of the cutting torch, nor can lead to any leaks. It is essential that the cutting nozzle rests defined on the support surface of the heating nozzle, which is ensured by the acting on the upper end face cutting oxygen pressure. This measure also simplifies the nozzle change and increases the reliability of the burner.

It has proven to be beneficial in the context to provide the cutting nozzle at its upper end with a frontally rounded outer edge. The frontally rounded outer edge facilitates the above-described axial insertion of the cutting nozzle into the first bore of the burner head.

In a particularly preferred embodiment of the cutting torch according to the invention, the heating nozzle has an outer jacket, which is provided at the upper end with a sealing ring, which bears sealingly against the second bore.

The second bore will also be referred to as the "hot-nozzle intake" below. By means of the sealing ring, the gas mixture guided in the heating nozzle is sealed to the outside (against the atmosphere) and at the same time the heating nozzle is radially fixed in the heating nozzle receptacle. For removal, the heating nozzle is pulled out of the heating nozzle receptacle in the direction of the longitudinal axis with elastic deformation of the sealing ring, and vice versa - the upper end of the heating nozzle is fixed by axial pressing into the heating nozzle receptacle. In this embodiment of the cutting torch, in which the radial fixing and the sealing of the heating nozzle to the outside takes place in a similar manner, as described above for the cutting nozzle as advantageous, arise advantages mentioned in terms of a low cost of nozzle replacement and improved tightness. Heating nozzle and cutting nozzle can be changed independently in the cutting torch according to the invention.

It has proven useful to provide the outer jacket of the heating nozzle downstream of the sealing ring with an outer collar which rests with an upstream annular surface on a front side annular surface of the burner head. By provided below the sealing ring outer collar results in a stop for the heating nozzle and thus a reproducible positioning to the burner head.

Preferably, the heating nozzle is fixed by means of a releasably engaging on the outer jacket of the heating nozzle coupling on the burner head, wherein the coupling has a passage inner bore with a radial cross-sectional constriction, which engages under an outwardly projecting extension of the heating nozzle. The coupling ensures on the one hand the positioning of the heating nozzle, and thus also indirectly the positioning of the voltage applied to the heating nozzle cutting nozzle with respect to the burner head. On the other hand, a clutch - in particular a quick-release coupling - allows a particularly simple and quick release and mounting of the nozzles on the burner head. For this purpose, the coupling is on the one hand releasably secured to the burner head and on the other hand it engages under an outwardly projecting extension of the heating nozzle, and fixes their position to the burner head. It is structurally particularly simple if this extension is formed by the outer collar of the heating nozzle.

It has proved to be advantageous if the outer jacket of the heating nozzle is provided with a lower sealing ring resting against the outer collar on the downstream side. In the case, the heating nozzle above the outer collar has a sealing ring and axially offset below a second, lower sealing ring. This is pressed by the outer collar engaging under the coupling against the downstream annular surface of the outer collar and thereby pushes the heating nozzle upwards, against the burner head. As a result, on the one hand, a clearance-free, manufacturing tolerances of the heating nozzle compensating fixing of the heating nozzle at the burner head achieved, and on the other hand, a further seal against the atmosphere.

In one embodiment of the cutting torch according to the invention with nozzle holder by means of releasable coupling results in a further relief when nozzle change when the outer jacket of the heating nozzle is provided with a circumferential outer groove with inserted O-ring, which provided in a downstream of the cross-sectional constriction inner groove in the inner bore of the coupling intervenes. The O-ring inserted in the circumferential outer groove engages in the inner groove of the coupling and forms a loose connection between the heating nozzle and coupling, so that upon release of the coupling from the burner head slipping out of the heating nozzle from the inner bore of the coupling both downwards and upwards is prevented. The two components - heating nozzle and clutch - but can be pulled apart against the resistance of the O-ring.

In a particularly preferred embodiment, the cutting torch according to the invention is equipped with a so-called slot nozzle. Here, the cutting nozzle has an outer shell, which is provided with circumferentially distributed longitudinal slots extending from the lower, downstream end of the cutting nozzle via an upstream provided therefor, a radially encircling bearing surface forming cross-sectional widening, and wherein the heating nozzle in the area between its upper, upstream end and its nozzle outlet with a radially encircling, upstream side support surface forming cross-sectional constriction is provided, on which the cutting nozzle rests with its support surface.

Due to the support of the cutting nozzle on the support surface of the heating nozzle, the two nozzles are axially fixed to each other. A positive connection between the heating nozzle and the cutting nozzle with each other or with the burner head is not required for this, so that the nozzle change in the cutting torch invention is facilitated overall. On the one hand, this leads to the fact that the cutting nozzle and heating nozzle can be detached from the burner head separately from one another without great effort and without the risk of damage to any passport or contact surfaces.

In a preferred embodiment of the cutting torch according to the invention, the distance between the upper end of the cutting nozzle and the bearing surface is between 25 mm and 35 mm. Such a short length of the cutting nozzle and a concomitant compact design of the cutting torch is achieved in particular when the cutting nozzle is held by means of sealing ring in the burner head, and not - as usual - by means of a threaded connection or pressure screw.

Preferably, a heating nozzle is used in which the distance between the support surface and the lower end of the heating nozzle is between 6 mm and 10 mm. The said distance limit values result as a compromise between the requirements of on the one hand a sufficient radial guidance of the cutting nozzle in the outer cylinder of the heating nozzle, and on the other hand a low overall height to provide a compact cutting torch as possible.

Preferably, the outer jacket of the cutting nozzle forms an outer cylinder downstream of the support surface, wherein the through hole of the heating nozzle is formed cylindrically downstream of the support surface and as a radial guide of the outer cylinder.

In the cutting torch according to the invention, the through hole of the heating nozzle is cylindrical in shape at least in the longitudinal section downstream of the support surface to the nozzle exit. This cylinder-shaped longitudinal section of the heating nozzle is referred to below as "inner cylinder".

In addition, the outer shell of the cutting nozzle is cylindrical at least in the longitudinal section between its support surface and the nozzle outlet. In this longitudinal section, the cutting nozzle is provided with the longitudinal slots distributed on the outer circumference, the envelope of which is referred to as "outer cylinder".

The inner cylinder of the heating nozzle serves as a radial guide for the downstream end of the cutting nozzle. For this purpose, the heating nozzle surrounds the outer cylinder of the cutting nozzle with little radial clearance. On the one hand, this leads to the cutting nozzle and the heating nozzle without much effort and without the risk of Damage of mating or contact surfaces can be separated from the burner head separated, and the guide contributes to the radial centering of the cutting nozzle. Due to the support of the cutting nozzle on the support surface of the heating nozzle, the two nozzles - as already mentioned above - also axially fixed to each other without the need for a form-fitting or reibschlüsiger connection is required.

The heating nozzle is due to its design with inner cylinder suitable for use with different cutting nozzles, for example, cutting nozzles for slow-burning fuel gases or for fast-burning fuel gases. This is explained in more detail below: Cutting nozzles for slow-burning and cutting nozzles for fast-burning fuel gases differ in their axial distance between the nozzle exits of the heating nozzle and cutting nozzle and by the Ausströmquerschnitt the heating nozzle for the fuel gas-oxygen mixture. In the cutting torch according to the invention, the distance is predetermined solely by the length of the respective outer cylinder of the cutting nozzle. The length of the outer cylinder is precisely adjustable without much production effort; a complex adaptation of the nozzles to each other is not required in the cutting torch according to the invention. When changing the combustion gases from fast-burning to slow-burning - or vice versa - the previous cutting nozzle can be replaced by a customized to the new requirements cutting nozzle, without replacement of the heating nozzle is required. The heating nozzle is suitable for use with any of the nozzles of the nozzle system and can be maintained even when replacing the cutting nozzle. This reduces the variety of nozzle shapes to be stocked, simplifies storage, and otherwise improves the reliability of the cutting torch of the present invention by avoiding combinations of inappropriate nozzles.

Among the extended uses of the invention

Schneidbrenner also contributes to the fact that the cylindrical nozzle shape - compared to conical nozzles - allows larger and more variable working distances between nozzle and workpiece surface; typically around 15 to 20 mm.

The nozzles of the cutting torch according to the invention are usually made of stainless steel, brass or ceramic. Especially with the metallic materials, an improvement in the wear resistance is achieved if the surface of the cutting nozzle and / or the surface of the heating nozzle has a hard material layer. This results in a longer nozzle life and less maintenance. Coatings of metal nitrides or carbides, for example CrN, TiN, TiC, WC, are particularly suitable as the hard material layer.

Figur 1:

eine Ansicht einer Schneiddüse für einen erfindungsgemäßen Schneidbrenner in einem Längsschnitt,

Figur 2:

eine Ansicht einer Heizdüse für einen erfindungsgemäßen Schneidbrenner in einem Längsschnitt,

Figur 3:

eine Ansicht eines Brennerkopfes für einen erfindungsgemäßen Schneidbrenner in einem Längsschnitt,

Figur 4:

eine Zusammenbauzeichnung einer ersten Ausführungsform eines erfindungsgemäßen, montierten Schneidbrenners in einem Längsschnitt,

Figur 5a:

einen Längsschnitt einer Schneiddüse für schnell verbrennendes Gas, montiert in einer Heizdüse,

Figur 5b:

einen Längsschnitt einer Schneiddüse für langsam verbrennendes Gas, montiert in einer Heizdüse, und

Figur 6

eine Zusammenbauzeichnung einer zweiten Ausführungsform eines erfindungsgemäßen, montierten Schneidbrenners in einem Längsschnitt.

The invention will be explained in more detail with reference to an embodiment and a drawing. In detail in the drawing:

FIG. 1:

a view of a cutting nozzle for a cutting torch according to the invention in a longitudinal section,

FIG. 2:

a view of a heating nozzle for a cutting torch according to the invention in a longitudinal section,

FIG. 3:

a view of a burner head for a cutting torch according to the invention in a longitudinal section,

FIG. 4:

an assembly drawing of a first embodiment of a mounted cutting torch according to the invention in a longitudinal section,

FIG. 5a

a longitudinal section of a cutting nozzle for fast burning gas, mounted in a heating nozzle,

FIG. 5b:

a longitudinal section of a cutting nozzle for slow-burning gas, mounted in a heating nozzle, and

FIG. 6

an assembly drawing of a second embodiment of a mounted cutting torch according to the invention in a longitudinal section.

Figure 4 shows a first embodiment of a mounted cutting torch according to the invention. This is part of a flame cutting machine for Oxyfuel cutting. The cutting torch consists essentially of a burner head 1, which is connected by a coupling 4 to a cutting nozzle 2, and to a heating nozzle 3 encompassing the cutting nozzle 2. In the following, the structural features of the individual components and their function with reference to Figures 1 to 3 and the assembly drawing of Figure 4 are explained in more detail.

The cutting nozzle 2 according to FIG. 1 consists of a substantially cylindrical brass part which is rotationally symmetrical about the center axis 15 and is provided with a hard material layer of chromium nitride (CrN). The outer shell of the cutting nozzle 2 has two cylindrical longitudinal sections, which differ in their diameter, and which are connected by a circumferential rectangular step 5 with a bearing surface facing downstream and perpendicular to the central axis 15 with a defined peripheral end edge 25. In the upper upstream side section 6 (upper outer cylinder), the outer diameter is 8 mm, and in the lower downstream side section 7 (upper outer cylinder), the outer diameter is 6 mm. The cutting nozzle 2 is part of the nozzle system according to the invention, which comprises a plurality of interchangeable cutting nozzles, which are each designed for a specific fuel gas and a predetermined power range. For all nozzles of this nozzle system, the upper outer cylinder 6 has a length of 30 mm. The length of the lower outer cylinder 7 is decisive for the suitability of the cutting nozzle with respect to the type of fuel gas. In the cutting nozzle 2, which is designed for fast-burning fuel gas, the length of the lower outer cylinder 7 is 8 mm.

The lower outer cylinder 7 and the adjoining part of the upper outer cylinder 6 are provided with a plurality of axial longitudinal slots 8, which are evenly distributed over the circumference of the outer shell, and extending over the step 5. The longitudinal slots 8 are used to supply a fuel gas-oxygen mixture to the heating nozzle outlet (see Figure 4).

At the upper end of the cutting nozzle 2, the outer shell has a circumferential groove, which is provided for receiving an O-ring 9 made of a heat-resistant material, such as silicone.

The frontal outer edge 10 at the upper end of the cutting nozzle 2 is rounded and projects into an inner bore 30 of the burner head 1, on the inner wall of the O-ring 9 sealingly.

By means of the O-ring 9, the cutting oxygen line 11 is sealed to the outside and at the same time the cutting nozzle 2 is radially fixed within an inner bore 30 of the burner head 1 (Figure 4). On an axial end-side stop for the cutting nozzle in the inner bore 30 is omitted, so that by axial clearance dimensional tolerances in the length of the cutting nozzle can be intercepted. The axial position of the cutting nozzle 2 is determined solely by the defined support on a supporting step 16 of the heating nozzle 3 (see FIG. 4), which is ensured by the cutting oxygen pressure acting on the upper end face 10. This type of support of the cutting nozzle 2 - directly on the burner head and without mechanical connection - requires little effort when changing the nozzle and it is also achieved a low overall height and improved compared to a metallic seal tightness.

In the central axis 15 of the cutting nozzle 2 extends the cutting oxygen channel 11, which is formed in the form of a Laval nozzle. The nozzle inlet 24 narrows funnel-shaped from top to bottom to ensure a low-turbulence gas inlet. After the nozzle inlet, the cutting oxygen channel 11 narrows in the form of an inner cone 12 in the upper end of the cutting nozzle 2 and opens in the lower end of the cutting nozzle 2 as a more or less cylindrical inner bore (Laval nozzle) at the nozzle outlet 13th

The heating nozzle 3 shown in Figure 2 consists of copper. It is also rotationally symmetrical about the central axis 15 and provided with a hard material layer of CrN. The heating nozzle 3 is suitable for receiving a cutting nozzle 2 according to FIG. For this purpose, the through hole 17 of the heating nozzle 3 in the region between its upper, upstream end and the nozzle outlet 14 on a radially encircling, upwardly directed support step 16 on which the cutting nozzle 2 rests with its downstream side bearing surface of the stage 5 (Figure 4). The through hole 17 is cylindrical below the support step 16 with an inner diameter of slightly more than 6 mm formed. The designated by the reference numeral 18 cylindrical length portion has a length of 10 mm and is used without forming a coherent connection as a radial guide for the lower outer cylinder 7 of the cutting nozzle 2. As a result, cutting nozzle 2 and the heating nozzle 3 can be changed separately.

The outer jacket of the heating nozzle 3 has a cone 19 tapering towards the nozzle outlet, which merges upward into a substantially cylindrical longitudinal section 20. At the upper end of the longitudinal section 20, a circumferential groove is provided with an O-ring 21 made of silicone, which sealingly abuts against the inner wall of an annular groove 33 in the burner head 1 (Figure 4).

By means of the O-ring 21, the supply line 26 (see FIG. 4) for the fuel-oxygen mixture is sealed off from the atmosphere, and at the same time the heating nozzle 3 is radially fixed within the annular groove 33 of the burner head 1 (FIG. 4). This type of fixation of the heating nozzle 3 requires little effort when changing the nozzle and it is also achieved a low overall height and improved compared to a metallic seal tightness.

Downstream of the O-ring 21, a circumferential outer collar 22 is provided, the upper side of which rests against a downwardly directed annular surface of the burner head 1 in the mounted cutting torch (see FIG. 4). At the bottom of the outer collar 22 engages the fixed to the burner head 1 clutch 4, as will be described in more detail below.

Another O-ring 38 abuts the outer jacket of the heating nozzle 3 and on the underside of the outer collar 22. This is pressed by the outer collar 22 under cross-coupling 4 against the underside of the outer collar 22 and thereby pushes the heating nozzle 3 upwards, against the burner head 1. By the two axially offset O-rings 21, 38 tilting of the heating nozzle 3 is prevented and Manufacturing tolerances of the heating nozzle 3 are compensated.

To facilitate a nozzle change, a loose connection is generated between the heating nozzle 3 and 4, the clutch 4, the release of the clutch Burner head 1 slipping out of the heating nozzle 3 from the inner bore of the clutch 4 prevents both downwards and upwards. For this purpose, a Umfangseinfräsung 23 is provided on the outer surface of the Heizdüse 3 below the outer collar 22, in which an O-ring 29 is inserted, which-as Figure 4 shows - engages in a corresponding inner groove in the clutch 4. Heating nozzle 3 and clutch 4 can only be pulled apart against the resistance of the O-ring 29.

FIG. 3 shows an exemplary embodiment of a burner head 1 for the cutting torch according to the invention. This consists of a substantially cylindrical brass component in which run the connection line 25 for the cutting oxygen and the connecting line 26 for the fuel gas-oxygen mixture, and on the outer jacket, the coupling 4 by means of ball traps 27, 28, the heating nozzle 3 and the cutting nozzle. 2 are releasably secured (Figure 4).

For this purpose, the nozzle (2,3) facing the lower part of the burner head 1 is provided with a central inner bore 30 which forms part of the connecting line 25 and which also serves as a receptacle for the upper end of the cutting nozzle 2. The inner bore 30 is provided for this purpose with a radial metallic sealing surface 32. Above this, an internal thread 31 is additionally provided. Thus, the burner head 1 is suitable both for receiving a cutting nozzle with a matching to the internal thread 31 standard external thread as well as for the sealing receiving a cutting nozzle 2, which is provided with a voltage applied to the sealing surface 32 O-ring 9 (as above with reference to FIG 1 described). For the axial fixation of the cutting nozzle 2 with O-ring 9 on the burner head 1, a cross-sectional constriction is provided in the region below the internal thread 31 against which the end face of the cutting nozzle 2 rests when installed (see FIG. 4).

Furthermore, the lower part of the burner head 1 is provided with an annular groove 33 beginning at the lower burner head end into which the connecting line 26 opens and which at the same time forms a receptacle for the upper end of the heating nozzle 3. The annular groove 33 is provided for this purpose with a radial metallic sealing surface 35, and above it in addition with an internal thread 34. Thus is the burner head 1 is suitable both for receiving a heating nozzle with an external thread suitable for the internal thread 34 and for sealingly receiving a heating nozzle 3 which is provided with an O-ring 21 contacting the sealing surface 35 (as described above with reference to FIG. 2). The outer collar 22 of the heating nozzle 3 serves for the axial fixing of the heating nozzle 3 on the burner head 1, by the upper side rests in the mounted cutting torch against an end face annular surface 36 of the burner head 1 (see Figure 4). In each case, the sealing surface 32 or 35 for receiving a nozzle 3, 4 with O-ring 9, 21 downstream of the respective internal thread 31, 34 are arranged.

The burner head 1 thus has two alternative elements for the production of the connection with a cutting nozzle projecting into the inner bore 30 and a heating nozzle 3 projecting into the annular groove 33. Namely, in each case an internal thread 31, 34 which corresponds to a corresponding external thread of cutting nozzle or heating nozzle, and in each case a radially encircling sealing surface 32, 35 against which the O-ring 9 on the outer surface of the cutting nozzle 3 and the O-ring 21 on the outer shell the heating nozzle 3 sealingly rests.

Thus, the burner head 1 can be used both for such nozzles, which are provided at its upper end with an external thread and for such nozzles, which - as provided in this embodiment - at its upper end a sealing ring (O-ring 9 and 21) exhibit.

From the assembly drawing of Figure 4 , in addition to the previously described components of the cutting torch according to the invention, the construction and function of the clutch 4 can be seen.

This consists essentially of a fixed to the burner head 1 by means of ball trap 27, 28 inner ring 40 which engages under a radial cross-sectional constriction 42, the outer collar 22 of the heating nozzle 3 and fixes them in their axial position. The inner ring 40 is surrounded by an outer ring 41, which is displaceable along the inner ring 40 against an axially downward spring force by releasing the ball trap 27, 28 upwards. The coupling 4 allows a quick change of the nozzles 2, 3. This also contributes to the type of sealing and mounting of the nozzles 2, 3 at the burner head 1 by means of O-ring seal.

The heating nozzle 3 described with reference to FIG. 2 is suitable both for receiving cutting nozzles for rapidly burning fuel gas and for receiving cutting nozzles for slowly burning fuel gases. This is shown in FIGS . 5a and 5b .

The cylindrical design of the heating nozzle 3 (see Figure 2) in the region of the inner cylinder 18 makes it suitable for use with different cutting nozzles. For this purpose, however, it is necessary that the cutting nozzles also have a corresponding cylindrical configuration in the region of the outer cylinder 7 (FIG. 1) and, moreover, in the upper upstream-side longitudinal section 6 have the same partial length. This is the case with the cutting nozzles 2a (FIG. 5a) and 2b (FIG. 5b). Thus, the cutting nozzles 2 a, 2 b exactly match the configuration prescribed by the burner head 1 and the heating nozzle 3.

The cutting nozzles 2a, 2b differ only in the length of the respective outer cylinder and by the flow cross sections of the nozzle slots. In the cutting nozzle 2a designed for fast-burning fuel gas, the length of the outer cylinder 7a is 8 mm, and in the cutting nozzle 2b designed for slow-burning fuel gas, the outer cylinder 7b has a length of 7 mm. Between the lower edge of the heating nozzle 3 (nozzle outlet 14) and the lower edge of the cutting nozzle 2a (nozzle outlet 13), this results in an axial distance of 0 mm and between the lower edge of the heating nozzle 3 (nozzle outlet 14) and the lower edge of the cutting nozzle 2b (nozzle outlet 13). an axial distance (reference numeral 50) of 1 mm.

When changing the type of fuel gas, the previous cutting nozzle can be replaced by a customized to the new requirements cutting nozzle, without replacement of the heating nozzle is required. The heating nozzle is suitable for use with any of the nozzles of the nozzle system and can be maintained even when replacing the cutting nozzle. This reduces the variety of nozzle shapes to be stocked, simplifies storage, and otherwise improves the reliability of the cutting torch of the present invention by avoiding combinations of inappropriate nozzles.

In another embodiment of the cutting torch according to the invention, a coupling in the form of a bayonet closure is provided for connecting the heating nozzle and the cutting nozzle to the burner head. The bayonet connection offers over the ball trap shown in Figure 4 a higher security against unintentional opening, but requires a slightly higher cost of automation of the nozzle change.

FIG. 6 shows such a second embodiment of the cutting torch for a gas cutting machine for oxy-fuel cutting. If identical reference numbers are used as in FIGS. 1 to 4 as well as FIGS. 5a and 5b, then the same or equivalent components and components are referred to, as explained in more detail above with reference to the description of the first embodiment of the cutting torch according to the invention. For reasons of a clearer illustration, the connection line for the fuel gas-oxygen mixture is not shown in FIG.

The cutting torch differs from the cutting torch according to FIG. 4 essentially in the manner of connecting the nozzles to the burner head 1. The cutting torch comprises a burner head 1, which has a cutting nozzle 2, and a heating nozzle 3 encompassing the cutting nozzle 2 by means of a coupling 61 connected in the form of a bayonet closure. The bayonet closure is formed essentially by two screw heads 62, which project from the burner head 1 and are opposite the burner head 1, the outer ring 41 and a milling cutout 63 encircling the inner side of the outer ring 41. When placing the burner head 1, the screw heads 62 are inserted into a schematically indicated in Figure 6 connecting groove 64 to the milled slot 63 and locked therein by a quarter turn.

The cutting torch shows yet a further modification with respect to the first embodiment explained above, with regard to the cutting nozzle. The cutting nozzle 2 consists of a rotationally symmetrical, substantially cylindrical brass part, which is provided with a hard material layer of nickel carbide (NiC). The only modification with respect to the cutting nozzle described with reference to Figure 1 is that in the region of the groove for the O-ring 9, a 20 micron thick and 5 mm wide ceramic layer 66 is provided.

Claims (16)

1. A flame cutter comprising a burner head having a central axis, which has connected thereto a cutting nozzle having an axial cutting oxygen duct, which is encompassed in the form of a cap by a heating nozzle having an axial through bore, the burner head comprising a cutting nozzle connection on which the upstream upper end of the cutting nozzle is sealingly received, and which is coaxially surrounded by a heating nozzle connection shaped in the form of an annular gap, on which the upstream upper end of the heating nozzle is sealingly received, characterized in that the cutting nozzle connection has a first bore (30) with an inner wall, which inner wall is provided with an inner thread (31) and with a first radially surrounding metallic sealing surface for sealingly receiving a cutting nozzle which is provided with an outer thread and rests on the first sealing surface, and with a second radially surrounding sealing surface (31) for sealingly receiving a cutting nozzle (2) with a sealing ring (9) resting on the second sealing surface (31).
2. The flame cutter according to claim 1, characterized in that the heating nozzle connection comprises a second bore (33) with an inner wall, which inner wall is provided with an inner thread (34) and a first radial metallic sealing surface for sealingly receiving a heating nozzle which is provided with an outer thread and rests on the first sealing surface, and with a second radially surrounding sealing surface (35) for sealingly receiving a heating nozzle (3) with a sealing ring (21) resting on the second sealing surface (35).
3. The flame cutter according to claim 1 or 2, characterized in that the outer covering of the cutting nozzle (2) is provided at the upper end with a sealing ring (9) which sealingly rests on the inner wall of the first bore.
4. The flame cutter according to claim 3, characterized in that the cutting nozzle (2) is held in the first bore (30) with an axial play.
5. The flame cutter according to any one of the preceding claims, characterized in that the cutting nozzle (2) is formed at its upper end with an outer edge (10) rounded off at the front side.
6. The flame cutter according to claim 2, characterized in that the heating nozzle (3) comprises an outer covering which is provided at the upper end with a sealing ring (21) which sealingly rests on the inner wall of the second bore (35).
7. The flame cutter according to claim 6, characterized in that the outer covering of the heating nozzle (3) is provided downstream of the sealing ring (21) with an outer collar (22) which rests with an upstream annular surface on a frontside annular surface (36) of the burner head (1).
8. The flame cutter according to claim 6 or 7, characterized in that the heating nozzle (3) is detachably fixed to the burner head (1) by means of a coupling device (4) acting on the outer covering of the heating nozzle (3), the coupling device (4) comprising an inner through bore having a radial cross-sectional constriction (42) which grips under an outwardly projecting extension of the heating nozzle (3).
9. The flame cutter according to claim 8, characterized in that the outwardly projecting extension is formed by the outer collar (22) of the heating nozzle (3).
10. The flame cutter according to claim 7 or 9, characterized in that the outer covering of the heating nozzle (3) is provided with a lower sealing ring (38) resting downstream on the outer collar (22).
11. The flame cutter according to claim 6 and any one of claims 8 to 10, characterized in that the outer covering of the heating nozzle (3) is provided with a surrounding outer groove (23) with an O-ring (29) inserted therein, which engages into an inner groove in the inner bore of the coupling device (4).
12. The flame cutter according to any one of the preceding claims, characterized in that the cutting nozzle (2) has an outer covering which is provided with longitudinal slots (8) which are distributed over the circumference and extend from the lower downstream end of the cutting nozzle (2) over a cross-sectional extension which is provided upstream thereof and forms a radially surrounding bearing surface (5), and the heating nozzle (3) in the area between its upper upstream end and its nozzle exit (13) being provided with a cross-sectional constriction which forms a radially surrounding upstream support surface (16) and on which the cutting nozzle (2) rests with its bearing surface (5).
13. The flame cutter according to claim 12, characterized in that the distance between the upper end of the cutting nozzle (2) and the bearing surface (5) is between 25 mm and 35 mm.
14. The flame cutter according to claim 12 or 13, characterized in that the distance between the support surface (16) and the lower end of the heating nozzle (3) is between 6 mm and 10 mm.
15. The flame cutter according to any one of claims 12 to 14, characterized in that the outer covering of the cutting nozzle (2) forms an outer cylinder downstream of the bearing surface (5), the through bore (17) of the heating nozzle (3) being cylindrical downstream of the support surface (16) and configured as a radial guide of the outer cylinder.
16. The flame cutter according to any one of the preceding claims, characterized in that the surface of the cutting nozzle (2) and/or the surface of the heating nozzle (3) has a hard material layer.

Images