WO2003025462A1

WO2003025462A1 - Flame cutter with a multi-functional burner head

Info

Publication number: WO2003025462A1
Application number: PCT/EP2002/009593
Authority: WO
Inventors: Rainald Vossberg
Original assignee: Messer Cutting & Welding Gmbh
Priority date: 2001-09-07
Filing date: 2002-08-28
Publication date: 2003-03-27
Also published as: DK1423643T3; CY1107843T1; EP1423643B1; DE50211019D1; PT1423643E; DE10144179C1; EP1423643A1; ATE374905T1; ES2295411T3

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

Patent application

Cutting torch with multifunctional torch head

The present invention relates to a cutting torch with a

Torch head having a central axis, to which a cutting nozzle with an axial cutting oxygen line is connected, which is encompassed in a cap-like manner by a heating nozzle having an axial through-bore, the burner head having a cutting nozzle connection, on which the upstream, upper end of the cutting nozzle is accommodated in an outwardly sealing manner. and which is coaxially surrounded by an annular gap-shaped heating nozzle connection, on which the upstream, upper end of the heating nozzle is received in a sealing manner to the outside.

Such a cutting torch is known from DE-T2 690 03 588. A cutting torch is described therein which has a cutting head to which a cutting nozzle with an axial oxygen line and an axial through-hole heating nozzle, which surrounds the cutting nozzle in a cap-like manner, are fastened. For this purpose, the heating nozzle and the cutting nozzle are provided with transverse end faces which correspond to corresponding transverse end faces of the burner head and which are fastened to the burner head by means of one

Union nut, which is supported on an outer collar of the heating nozzle, pulled against each other, so that there is a sealing metallic connection of the respective transverse end faces to the outside.

In the known cutting torch, the cutting nozzle is designed as a so-called slot nozzle. This is formed from a piece of metal that has an outer frustoconical shape with a wide upstream end and a narrower downstream end. The axial cutting oxygen line extends from the upper end to the nozzle outlet. On the outer circumference, the cutting nozzle has a series of radial ribs (longitudinal slots) which are formed by longitudinal milling in the metal body and which extend from the downstream end of the cutting nozzle to an outer collar provided on the upstream side

CONFlRMATiON C0PY 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 which tapers conically towards the downstream end. The inner bore has the aforementioned radial inner recess in its upper region. The conical part of the inner bore, which begins downstream of it, is kept somewhat narrower than the envelope of the cutting nozzle ribs, so that it can be frictionally fixed in the heating nozzle by pressing in from above. The axial stop position results from the support of the outer collar and inner recess.

The production of such conical contact surfaces in the 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 limited to a short working distance between the nozzle and the workpiece surface in the range of 5 to 7 mm because of the taper of the nozzles.

During operation of the cutting torch, contamination occurs, in particular the cutting oxygen line, which leads to a deterioration in performance. Regular cleaning is therefore required, in which the nozzles must be completely disassembled. This has an adverse effect on the fit of the conical contact surfaces of the heating nozzle and cutting nozzle and can also damage the nozzles. Since the cutting nozzle is subject to greater wear, it would also be desirable to be able to replace it 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 outlay for storage and changing the different nozzles. The known cutting torch has a compact construction area; however, it is only designed for use with nozzles that have a transverse sealing surface that corresponds to the respective transverse sealing surfaces of the burner head.

Cutting torches are also known in which the cutting nozzle and the heating nozzle are held on the torch head by means of a screw connection.

The present invention is therefore based on the object of providing a cutting torch which can be used flexibly - in particular for a flame cutting machine - with a simple, compact design of the nozzles, which is associated with easier maintenance, easier maintenance and cost-effective production, and in which the effort for Storage of wear parts is reduced.

Starting from a cutting torch with the features mentioned at the outset, this object is achieved according to the invention in that the cutting nozzle connection has a first bore with an inner wall which is provided with a

Internal thread and is provided with a first radially circumferential, metallic sealing surface for the sealing reception of a cutting nozzle provided with an external thread and resting on the first sealing surface, and that the inner wall with a second radially circumferential sealing surface for the sealing reception of a cutting nozzle with one on the second sealing surface adjacent sealing ring is provided.

The torch head according to the invention thus has two different connections for the cutting nozzle. The connections each comprise a first bore (hereinafter also referred to as “cutting nozzle receptacle”), into which the upper end of the cutting nozzle extends.

At least two different elements are provided for establishing the connection with a cutting nozzle. One of the elements is an internal thread, which corresponds to an external thread of the cutting nozzle, a seal usually being produced to the outside by the contact force generated when screwing in between contact surfaces lying against one another becomes. The other element is a radially circumferential sealing surface, which forms a tight connection with a sealing ring of the cutting nozzle.

As a result, the burner head can be used both for cutting nozzles that are provided with an external thread at their upper end and for those cutting nozzles that have a sealing ring (O-ring) at their upper end. In this respect, the torch head is designed to be multifunctional, which also contributes to reduced storage for the cutting nozzles and the associated lower manufacturing costs.

In addition, a particularly preferred embodiment of the cutting torch according to the invention, the heating nozzle connection has a second bore with an inner wall, which is provided with an internal thread and a first radial, metallic sealing surface for the sealing reception of a heating nozzle provided with an external thread and resting on the first sealing surface , wherein the inner wall is provided with a second radially circumferential sealing surface for the sealing reception of a heating nozzle with a sealing ring abutting the second sealing surface.

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

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

The cutting oxygen line is sealed to the outside by means of the sealing ring and at the same time the cutting nozzle is fixed radially in the cutting nozzle receptacle. The cutting nozzle is pulled out of 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, moreover, an improved tightness compared to a metallic seal is achieved. The sealing ring is usually a ring made of elastic material which is in contact with the outer jacket or is inserted in an annular groove of the same.

A further improvement results if the cutting nozzle is held in the first bore with axial play. The cutting nozzle is only fixed radially in the first bore, while there is no axial stop position in the direction of the central axis. The axial play compensates for dimensional tolerances in the length of the cutting nozzle, so that they neither have an influence on the external dimensions of the cutting torch, nor can they lead to any leaks. It is essential that the cutting nozzle lies in a defined manner on the support surface of the heating nozzle, which is ensured by the cutting oxygen pressure acting on the upper end face. This measure also simplifies the nozzle change and increases the operational reliability of the burner.

In connection with this, it has proven to be advantageous to provide the cutting nozzle with an outer edge rounded at its top end. The rounded outer edge facilitates the above-described axial insertion of the cutting nozzle into the first bore of the torch 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 lies sealingly against the second bore.

The second hole is also referred to below as the "heating nozzle holder". The sealing ring seals the gas mixture in the heating nozzle to the outside (against the atmosphere) and at the same time fixes the heating nozzle radially in the heating nozzle holder. The heating nozzle is removed for removal 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 axially pressing it into the heating nozzle receptacle to the outside in a manner similar to that described above as being advantageous for the cutting nozzle, there are advantages mentioned with regard to a low outlay when changing the nozzle and an improved tightness. The heating nozzle and cutting nozzle can be replaced independently of one another in the cutting torch according to the invention.

It has proven useful to face the outer jacket of the heating nozzle downstream

Sealing ring with an outer collar, which rests with an upstream ring surface on an end ring surface of the burner head. The outer collar provided below the sealing ring results in a stop for the heating nozzle and thus a reproducible positioning in relation to the burner head.

The heating nozzle is preferably fixed to the burner head by means of a coupling which engages detachably on the outer jacket of the heating nozzle, the coupling having a through-bore with a radial cross-sectional constriction which engages under an outwardly extending 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 cutting nozzle on the heating nozzle in relation to the burner head. On the other hand, a coupling - in particular a quick-release coupling - enables the nozzles to be released and mounted on the burner head in a particularly simple and quick manner. For this purpose, the coupling is detachably fastened to the burner head on the one hand and, on the other hand, it engages under an outwardly extending extension of the heating nozzle and fixes its position in relation to the burner head. It is structurally particularly simple if this extension is formed by the outer collar of the heating nozzle.

It has proven to be advantageous if the outer jacket of the heating nozzle is provided with a lower sealing ring which bears against the outer collar on the downstream side. In this case, the heating nozzle has a sealing ring above the outer collar and, axially offset below it, a second, lower sealing ring. This is pressed by the coupling under the outer collar against the downstream annular surface of the outer collar and thereby pushes the heating nozzle upwards against the burner head. On the one hand, this results in a play-free, manufacturing tolerances of the heating nozzle compensating fixation of the heating nozzle on the burner head achieved, and on the other hand a further seal against atmosphere.

In one embodiment of the cutting torch according to the invention with a nozzle holder by means of a detachable coupling, there is a further relief when changing the nozzle if the outer jacket of the heating nozzle is provided with a circumferential outer groove with an O-ring inserted therein, the inner groove provided downstream of the cross-sectional constriction 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 the coupling, so that when the coupling is released from the burner head

The heating nozzle slips out of the inner bore of the coupling both downwards and upwards. The two components - heating nozzle and coupling - can be pulled apart against the resistance of the O-ring.

In a particularly preferred embodiment, the invention is

Cutting torch equipped with a so-called slot nozzle. Here, the cutting nozzle has an outer jacket which is provided with longitudinal slots distributed around the circumference, which extend from the lower, downstream end of the cutting nozzle via a cross-sectional widening provided upstream thereof and forming a radially circumferential bearing surface, and the heating nozzle in the region between its upper, upstream end and its nozzle outlet is provided with a cross-sectional constriction forming a radial circumferential, upstream support surface, on which the cutting nozzle rests with its support surface.

By resting the cutting nozzle on the support surface of the heating nozzle, the two nozzles are fixed axially to one another. A positive connection between the heating nozzle and the cutting nozzle with one another or with the torch head is not necessary for this, so that the nozzle change in the cutting torch according to the invention is made easier overall. On the one hand, this means that the cutting nozzle and heating nozzle can be easily and without the risk of

Damage to any fitting or contact surfaces can be solved separately from the burner head. In a preferred embodiment of the cutting torch according to the invention, the distance between the upper end of the cutting nozzle and the contact surface is between 25 mm and 35 mm. Such a short length of the cutting nozzle and an associated compact design of the cutting torch is achieved in particular if the cutting nozzle is by means of

Sealing ring is held in the burner head, and not - as usual - by means of a threaded connection or pressure screw.

A heating nozzle is preferably 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 distance limits mentioned are a compromise between the requirements, on the one hand, of adequate radial guidance of the cutting nozzle in the outer cylinder of the heating nozzle, and, on the other hand, of a low overall height in order to provide a cutting torch that is as compact as possible.

The outer jacket of the cutting nozzle preferably forms an outer cylinder downstream of the support surface, the through-bore of the heating nozzle downstream of the support surface being cylindrical and designed as a radial guide for the outer cylinder.

In the cutting torch according to the invention, the through bore of the heating nozzle is cylindrical at least in the longitudinal section downstream of the support surface up to the nozzle outlet. This cylindrical section of the heating nozzle is referred to below as the “inner cylinder”.

In addition, the outer jacket of the cutting nozzle is also cylindrical at least in the longitudinal section between its support surface and the nozzle outlet. In this length section, the cutting nozzle is provided with the longitudinal slots distributed on the outer circumference, the envelope of which is referred to as the “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 play. On the one hand, this means that the cutting nozzle and heating nozzle can be easily and without the risk of Damage to fitting or contact surfaces can be solved separately from the torch head, and the guide contributes to the radial centering of the cutting nozzle. By placing the cutting nozzle on the support surface of the heating nozzle, the two nozzles - as already mentioned above - are also axially fixed to one another without a positive or frictional connection being required for this.

Due to its design with an inner cylinder, the heating nozzle is suitable for use with different cutting nozzles, for example cutting nozzles for slowly burning fuel gases or for rapidly 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 outlets of the heating nozzle and cutting nozzle and in the cross-section of 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 can be exactly adjusted without great manufacturing effort; a complex adaptation of the nozzles to one another is not necessary in the cutting torch according to the invention. When changing the fuel gases from fast-burning to slow-burning - or vice versa - the previous cutting nozzle can be replaced by the new one

Cutting nozzle adapted to the requirements can be replaced without having to replace the heating nozzle. The heating nozzle is suitable for use with any of the cutting nozzles in the nozzle system and can also be retained when the cutting nozzle is replaced. This reduces the variety of the nozzle shapes to be stored, simplifies storage and improves the operational safety of the cutting torch according to the invention by avoiding combinations of unsuitable nozzles.

The fact that the cylindrical nozzle shape - in comparison to conical nozzles - allows larger and more variable working distances between the nozzle and the workpiece surface also contributes to the expanded application possibilities of the cutting torch according to the invention; typically between about 15 to 20 mm. The nozzles of the cutting torch according to the invention are usually made of stainless steel, brass or ceramic. In the case of metallic materials in particular, an improvement in 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 service life for the nozzles and less maintenance. In particular, coatings made of metal nitrides or carbides, such as CrN, TiN, TiC, WC, come into consideration as the hard material layer.

The invention is explained in more detail below using an exemplary embodiment and a drawing. The drawings show in detail:

FIG. 1 shows a longitudinal section of a cutting nozzle for a cutting torch according to the invention,

FIG. 2 shows a longitudinal section of a heating nozzle for a cutting torch according to the invention,

FIG. 3 shows a longitudinal section of a torch head for a cutting torch according to the invention,

FIG. 4: an assembly drawing of a first embodiment of an assembled cutting torch according to the invention in a longitudinal section,

FIG. 5a: a longitudinal section of a cutting nozzle for rapidly burning gas, mounted in a heating nozzle,

Figure 5b: a longitudinal section of a cutting nozzle for slowly burning gas, mounted in a heating nozzle, and

Figure 6 is an assembly drawing of a second embodiment of an assembled cutting torch according to the invention in one

Longitudinal section.

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

The cutting nozzle 2 according to FIG. 1 consists of a substantially cylindrical brass part which is rotationally symmetrical about the central axis 15 and which is provided with a hard material layer made of chromium nitride (CrN). The outer jacket 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 support surface pointing downstream and perpendicular to the central axis 15 and having a defined, circumferential end edge 25. In the upper upstream length section 6 (upper outer cylinder) the outer diameter is 8 mm, in the lower downstream length 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, each of which is designed for a specific fuel gas and a predetermined output range. With 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 regard 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 adjacent part of the upper

Outer cylinders 6 are provided with a plurality of axial longitudinal slots 8, which are evenly distributed over the circumference of the outer jacket, and which extend over the step 5. The longitudinal slots 8 are used to supply a fuel gas-oxygen mixture for the outlet of the heating nozzle (see FIG. 4).

At the upper end of the cutting nozzle 2, the outer jacket has a circumferential groove which is provided for receiving an O-ring 9 made of a heat-resistant material, for example silicone. The front outer edge 10 at the upper end of the cutting nozzle 2 is rounded and protrudes into an inner bore 30 of the burner head 1, on the inner wall of which the O-ring 9 lies sealingly.

The cutting oxygen line 11 is sealed to the outside by means of the O-ring 9, and at the same time the cutting nozzle 2 is radially fixed within an inner bore 30 of the torch head 1 (FIG. 4). An axial end stop for the cutting nozzle in the inner bore 30 is dispensed with, so that dimensional tolerances in the length of the cutting nozzle can be absorbed by axial play. The axial position of the cutting nozzle 2 is determined solely by the defined support on a support 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 mounting of the cutting nozzle 2 - directly on the torch head and without mechanical connection - requires little effort when changing the nozzle and, in addition, a low overall height and an improved seal compared to a metallic seal are achieved.

The cutting oxygen channel 11, which is designed in the form of a Laval nozzle, runs in the central axis 15 of the cutting nozzle 2. The nozzle inlet 24 narrows in a funnel shape from top to bottom in order 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 into the lower end of the cutting nozzle 2 as a more or less cylindrical inner bore (Laval nozzle) at the nozzle outlet 13.

The heating nozzle 3 shown in Figure 2 is made of copper. It is also rotationally symmetrical about the central axis 15 and with a

Provide hard material layer made of CrN. The heating nozzle 3 is suitable for receiving a cutting nozzle 2 according to FIG. 1. For this purpose, the through-bore 17 of the heating nozzle 3 in the area between its upper, upstream end and the nozzle outlet 14 has a radially circumferential, upwardly directed support step 16, on which the cutting nozzle 2 rests with its downstream contact surface of step 5 (FIG. 4). The through hole 17 is cylindrical below the support step 16 with an inner diameter of slightly more than 6 mm. The cylindrical length section marked with the reference number 18 has a length of 10 mm and serves as a radial guide for the lower outer cylinder 7 of the cutting nozzle 2 without forming a coherent connection. This enables the cutting nozzle 2 and heating nozzle 3 to be replaced separately.

The outer jacket of the heating nozzle 3 has a cone 19 which tapers towards the nozzle outlet and merges upwards into an essentially cylindrical length section 20. At the upper end of the length section 20 there is a circumferential groove with an O-ring 21 made of silicone, which lies sealingly against the inner wall of an annular groove 33 in the burner head 1 (FIG. 4).

The supply line 26 (see FIG. 4) for the fuel-oxygen mixture is sealed from the atmosphere by means of the O-ring 21, and at the same time the heating nozzle 3 is fixed radially 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, in addition, a low overall height and an improved seal compared to a metallic seal are achieved.

A circumferential outer collar 22 is provided downstream of the O-ring 21, the upper side of which rests in the mounted cutting torch against an annular surface of the torch head 1 directed downward (see FIG. 4). At the

The underside of the outer collar 22 engages the coupling 4 attached to the burner head 1, as will be described in more detail below.

Another O-ring 38 rests on the outer jacket of the heating nozzle 3 and on the underside of the outer collar 22. This is pressed by the coupling 4 under the outer collar 22 against the underside of the outer collar 22 and thereby presses the heating nozzle 3 upwards, against the burner head 1. The two axially offset O-rings 21, 38 prevent the heating nozzle 3 from tilting and manufacturing tolerances of the heating nozzle 3 are compensated.

In order to facilitate a nozzle change, a loose connection is generated between the heating nozzle 3 and the coupling 4, which is released when the coupling 4 is released Burner head 1 prevents the heating nozzle 3 from slipping out of the inner bore of the coupling 4 both downwards and upwards. For this purpose, a circumferential milling 23 is provided on the outer jacket of the heating nozzle 3 below the outer collar 22, into which an O-ring 29 is inserted, which - as FIG. 4 shows - engages in a corresponding inner groove in the coupling 4.

The heating nozzle 3 and coupling 4 can only be pulled apart against the resistance of the O-ring 29.

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

For this purpose, the lower part of the torch head 1 facing the nozzles (2, 3) 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. For this purpose, the inner bore 30 is provided with a radial metallic sealing surface 32. An internal thread 31 is additionally provided above it. Thus, the burner head 1 is suitable both for receiving a cutting nozzle with a standard external thread matching the internal thread 31 and for sealingly receiving a cutting nozzle 2 which is provided with an O-ring 9 abutting the sealing surface 32 (as above with reference to FIG 1 described). For the axial fixation of the cutting nozzle 2 with O-ring 9 on the torch head 1 is in the area below the internal thread 31

Cross-sectional constriction is provided, against which the end face of the cutting nozzle 2 lies in the installed state (see FIG. 4).

Furthermore, the lower part of the burner head 1 is provided with an annular groove 33 beginning at the lower end of the burner head, 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. For this purpose, the annular groove 33 is provided with a radial metallic sealing surface 35 and, above it, also with an internal thread 34 the burner head 1 is suitable both for receiving a heating nozzle with an external thread matching the internal thread 34 and for sealingly receiving a heating nozzle 3, which is provided with an O-ring 21 resting on the sealing surface 35 (as described above with reference to FIG. 2). The outer collar 22 of the heating nozzle 3 serves to axially fix the heating nozzle 3 to the torch head 1, in that the upper side thereof rests in the mounted cutting torch against an end annular surface 36 of the torch head 1 (see FIG. 4). In each case, the sealing surface 32 or 35 for receiving a nozzle 3, 4 with an O-ring 9, 21 is arranged downstream of the respective internal thread 31, 34.

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

As a result, the burner head 1 can be used both for those nozzles which are provided with an external thread at their upper end and for those nozzles which - as provided in this exemplary embodiment - have a sealing ring (O-ring 9 or 21) at their upper end. exhibit.

In addition to the components of the cutting torch according to the invention described so far, the construction and function of the coupling 4 can be seen from the assembly drawing according to FIG.

This essentially consists of an inner ring 40 fixed to the burner head 1 by means of a ball trap 27, 28, which with a radial cross-sectional constriction 42 engages under the outer collar 22 of the heating nozzle 3 and fixes it in its axial position. The inner ring 40 is surrounded by an outer ring 41 which can be displaced upward along the inner ring 40 against an axially downward spring force by loosening the ball latch 27, 28. The coupling 4 enables the nozzles 2, 3 to be changed quickly. The type of sealing and holding of the nozzles 2, 3 on the burner head 1 by means of an O-ring seal also contributes to this. 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 Figures 5a and 5b.

The cylindrical design of the heating nozzle 3 (see FIG. 2) in the area 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 design in the area of the outer cylinder 7 (FIG. 1) and in addition in the upper upstream length section 6 the same partial length. This is the case with the cutting nozzles 2a (FIG. 5a) and 2b (FIG. 5b). The cutting nozzles 2a, 2b thus fit exactly to the configuration specified by the burner head 1 and heating nozzle 3.

The cutting nozzles 2a, 2b differ only in the length of the respective outer cylinder and in the flow cross sections of the nozzle slots. In the cutting nozzle 2a, which is designed for fast-burning fuel gas, the length of the outer cylinder 7a is 8 mm, and in the cutting nozzle 2b, which is designed for slow-burning fuel gas, the outer cylinder 7b has a length of 7 mm. This results in an axial distance of 0 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) 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 number 50) of 1 mm.

When changing the type of fuel gas, the previous cutting nozzle can be replaced by a cutting nozzle adapted to the new requirements, without the need to replace the heating nozzle. The heating nozzle is suitable for use with any of the cutting nozzles in the nozzle system and can also be retained when the cutting nozzle is replaced. This reduces the variety of the nozzle shapes to be stored, simplifies storage and improves the operational safety of the cutting torch according to the invention by avoiding combinations of unsuitable nozzles. In another embodiment of the cutting torch according to the invention, a coupling in the form of a bayonet lock is provided for connecting the heating nozzle and cutting nozzle to the torch head. Compared to the ball trap shown in FIG. 4, the bayonet connection offers greater security against unintentional opening, but requires somewhat more effort for automating the nozzle change.

FIG. 6 shows such a second embodiment of the cutting torch for an oxyacetylene cutting machine. If identical reference numerals are used here as in FIGS. 1 to 4 and 5a and 5b, the same or equivalent components and components are used, as are 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 connecting line for the fuel gas / oxygen mixture is not shown in FIG. 6.

The cutting torch differs from the cutting torch according to FIG. 4 essentially in the type of connection of the nozzles to the torch head 1. The cutting torch consists of a torch head 1 which has a cutting nozzle 2 and a heating nozzle 3 which surrounds the cutting nozzle 2 by means of a coupling 61 is connected in the form of a bayonet catch. The bayonet catch is essentially formed by two screw heads 62 which lie opposite one another on the burner head 1 and protrude from the burner head 1, the outer ring 41 and a milling 63 running around the inside of the outer ring 41. When the burner head 1 is put on, the screw heads 62 are inserted into a connecting groove 64, schematically indicated in FIG. 6, to the milled-in area 63 and locked therein by a quarter turn.

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

Claims

claims

1. Cutting torch with a central axis having a torch head, with which a cutting nozzle with an axial cutting oxygen line is connected, which is encompassed in a cap-like manner by a heating nozzle having an axial through-bore, the torch head having a cutting nozzle connection on which the upstream, upper end of the cutting nozzle is received sealingly to the outside, and which is coaxially surrounded by an annularly shaped heating nozzle connection, on which the upstream, upper end of the heating nozzle is received sealingly to the outside, characterized in that the cutting nozzle connection has a first bore (30) with an inner wall , which is provided with an internal thread (31) and with a first radially circumferential, metallic sealing surface for the sealing reception of an externally threaded cutting nozzle which is in contact with the first sealing surface, and that the inner wall with a second radially circumferential sealing surface (31) for di e sealing receptacle of a cutting nozzle (2) is provided with a sealing ring (9) abutting the second sealing surface (31).

2. Cutting torch according to claim 1, characterized in that the heating nozzle connection has a second bore (33) with an inner wall, which has an internal thread (34) and a first radial, metallic sealing surface for the sealing reception of an externally threaded and on the Is provided the first sealing surface adjacent heating nozzle, and that the inner wall with a second radially circumferential sealing surface (35) for sealingly receiving a heating nozzle (3) with one on the second sealing surface

(35) adjacent sealing ring (21) is provided.

3. Cutting torch according to claim 1 or 2, characterized in that the outer jacket of the cutting nozzle (2) is provided at the upper end with a sealing ring (9) which bears sealingly on the inner wall of the first bore.

4. Cutting torch according to claim 3, characterized in that the cutting nozzle (2) is held in the first bore (30) with axial play.

5. Cutting torch according to one of the preceding claims, characterized in that the cutting nozzle (2) is formed at its upper end with a rounded outer edge (10).

6. Cutting torch according to one of the preceding claims, characterized in that the heating nozzle (3) has an outer jacket which is provided at the upper end with a sealing ring (21) which bears against the outside of the inner wall of the second bore (35).

7. Cutting torch according to claim 6, characterized in that the

The outer jacket of the heating nozzle (3) is provided on the downstream side of the sealing ring (21) with an outer collar (22) which bears with an upstream ring surface on an end ring surface (36) of the burner head (1).

8. Cutting torch according to claim 6 or 7, characterized in that the heating nozzle (3) by means of an on the outer jacket of the heating nozzle (3) engaging

Coupling (4) is detachably fixed to the burner head (1), the coupling (4) having a through-hole with a radial cross-sectional constriction (42) which engages under an outwardly extending extension of the heating nozzle (3).

9. Cutting torch according to claim 8, characterized in that the outwardly projecting extension is formed by the outer collar (22) of the heating nozzle (3).

10. Cutting torch according to claim 7 or 9, characterized in that the outer jacket of the heating nozzle (3) with a downstream on the outer collar (22) adjacent lower sealing ring (38) is provided.

11. Cutting torch according to claim 6 and one of claims 8 to 10, characterized in that the outer jacket of the heating nozzle (3) is provided with a circumferential outer groove (23) with an O-ring (29) inserted therein, which in an inner groove in the Internal bore of the clutch (4) engages.

12. Cutting torch according to one of the preceding claims, characterized in that the cutting nozzle (2) has an outer jacket which is provided with circumferentially distributed longitudinal slots (8) which extend from the lower, downstream end of the cutting nozzle (2) via an upstream thereof The cross-sectional widening provided, which forms a radially circumferential support surface (5), and the heating nozzle (3) is provided with a cross-sectional constriction forming a radially circumferential, upstream support surface (16) in the area between its upper, upstream end and its nozzle outlet (13). on which the cutting nozzle (2) rests with its support surface (5).

13. Cutting torch according to claim 12, characterized in that the distance between the upper end of the cutting nozzle (2) and the support surface (5) is between 25 mm and 35 mm.

14. Cutting torch 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. Cutting torch according to one of claims 12 to 14, characterized in that the outer jacket of the cutting nozzle (2) downstream of the support surface (5) forms an outer cylinder, the through hole (17) of the heating nozzle (3) downstream of the support surface (16) cylindrical and is designed as a radial guide of the outer cylinder.

16. Cutting torch according to 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.