EP1423644B1 - Flame cutter - Google Patents

Abstract

Disclosed is a flame cutter, comprising a burner head (1) connected to a cutting nozzle (2) which is encompassed by a heating nozzle (3) in the form of a cap. The cutting nozzle (2) has an outer covering with a radially revolving bearing surface (5). The heating nozzle (3) is provided with a radially revolving support surface (16) upon which the bearing surface (5) of the cutting nozzle (2) rests. In order to provide a flame cutter which can be used in a flexible manner especially in a blow-torch cutter machine fitted with nozzles which are both simple and compact and which are easy to maintain and service and which can be produced at low cost, the outer covering of the cutting nozzle (2) is embodied as a lower outer cylinder (7) downstream from the bearing surface (5) and the through-hole (17) of the heating nozzle (3) is cylindrical downstream from the support surface (16), being embodied as a radial guide for the lower outer cylinder (7). The inventive nozzle system comprises nozzles for slowly combustible combustion gases and for quickly combustible combustion gases. According to said system, storage costs for the wearing elements are low and the inventive nozzle system is characterised in that it comprises the heating nozzle (3) and several replaceable cutting nozzles (2a;2b) which are respectively designed for a combustion gas and a power range, all having a partial length adapted to a respective combustion gas between the bearing surface (5) and the nozzle exit (13).

Description

The present invention relates to a cutting torch having a central axis having a burner head, to which a metallic cutting nozzle with axial cutting oxygen line is cap-like embraced by a axial through-bore heating nozzle, wherein the cutting nozzle has an outer shell, which provided with circumferentially distributed longitudinal slots which extends from the lower, downstream end of the cutting nozzle via a provided therefrom, a radially encircling bearing surface forming cross-sectional widening, and wherein the heating nozzle in the region 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, wherein the outer jacket of the cutting nozzle is formed downstream of the support surface as a lower outer cylinder, and the Durc Cylinder bore of the heating nozzle downstream of the support surface is cylindrical and formed as a radial guide for the lower outer cylinder.

Furthermore, the invention relates to a use of the cutting torch with a nozzle system for a cutting torch for - in connection with oxygen - slow-burning and fast-burning fuel gases.

In the cutting technology, different fuel gases are used, which can be subdivided into slow-burning and fast-burning fuel gases. Advantageously, the cutting torch of a flame cutting machine should, if necessary, with fuel gases of one or the other category can be operated. However, this usually requires a change of cutting torch nozzles. Frequently also on one

Flame cutting machine used both cutting torch for slow burning and cutting torch for fast burning fuel gases.

For flame cutting mainly ring or slot nozzles are used. These consist of two parts, the cutting nozzle and the heating cap or

Heating nozzle. When changing the nozzle, these are connected together in succession or by pressure screw together, screwed metallic sealing into the burner head.

The cutting operation is carried out with a fuel gas heating oxygen flame and cutting oxygen. The cutting oxygen is supplied to the cutting nozzle via an axial cutting oxygen line, while the fuel gas-oxygen mixture is supplied from a Brennstoffgemischverteilkammer coming to the heating nozzle, which surrounds the cutting nozzle in the form of an annular gap. The heat given off by the heating flame and the heat produced by the combustion of the workpiece allows continuous combustion by the cutting oxygen jet.

A cutting torch of the type mentioned is in the DE-T2 690 03 588 described. 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. On the outer circumference, 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, with which the cutting nozzle on a radial inner recess in the inner bore of the heating nozzle rests.

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.

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, 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.

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 case of the known cutting torch, a selection of different cutting nozzles and matched heating nozzles must be available for this purpose, which is accompanied by a corresponding effort for storage and the replacement of the different nozzles.

Another cutting torch with cutting nozzle in the form of a slot is in the DE 818 482 and in the DE 840 683 C described. The cutting nozzle is formed from a piece of metal having an outer frusto-conical shape with a wider upstream end and a short, cylindrically tapered collar. The upper end of the cutting nozzle is provided with an external thread, which is screwed gas-tight into a corresponding receptacle of the burner head, whereby the axial stop position of the cutting nozzle is predetermined.

The heating nozzle is characterized by a solid part with a cylindrical top, then conically tapered down and back to the bottom formed cylindrical expiring inner bore. The upper end of the heating nozzle is provided with an external thread, by means of which the heating nozzle is gas-tightly connected to the burner head. This results in the axial fixation of the heating nozzle. The conical part of the inner bore is kept slightly narrower than the outer cone of the cutting nozzle, so that a gap remains between the heating nozzle and the cutting nozzle. Also between the collar of the cutting nozzle and the lower part of the inner bore of the heating nozzle, a significant gap is provided, so that there is no contact between the cutting nozzle and the heating nozzle in this cutting torch.

However, the replacement of the cutting nozzle designed in this cutting torch very expensive. First, the gas-tight screw connection of the heating nozzle and then the cutting nozzle must be opened. In order to accomplish this, sections of the nozzles are provided with hexagonal outer profiles, which fits to wrenches. The production of the conical nozzle parts is expensive and small deviations in the production or assembly lead to significant differences in the gap between the nozzles and thus to non-reproducible operating results. By repeated nozzle change suffers beyond the tightness of the screw.

From the US 2,897,884 a cutting torch with a cutting nozzle is to be removed, where the heating nozzle and cutting nozzle are gas-tight screwed together. Furthermore, the cutting nozzle is fixed by means of thread on the burner head. The replacement of the cutting nozzle is also expensive here.

A simplification of the tool change in flame cutting machines for oxy-fuel or plasma cutting, especially in machines with a large portal width leads to the reduction of set-up times and thus to the effective use of the machines and to faster adaptability to changing manufacturing tasks. The replacement of the nozzles is necessary, for example, when the nozzle has to be replaced by metal splashes or wear or when the cutting area of the nozzle does not match the thickness of the workpiece to be cut.

In the DE-A1 37 35 598 a device for automatic change of cutting nozzles in a flame cutting machine for oxy-fuel or plasma cutting is described, in which a machine control is provided, by means of which the burners are moved to a nozzle bearing, wherein the nozzle to be replaced positioned over a discharge point, there dissolved, then the burner moved to a loading point and equipped with a new nozzle. For holding the nozzles to the burners, a coupling operating according to the quick-acting principle is provided. For this purpose, in each case a cutting nozzle and a cutting nozzle surrounding the cutting nozzle heating nozzle are screwed to an adapter piece. Within this adapter piece, the gas ducts from the burner head to the heating nozzle and from the burner head to the cutting nozzle are sealed and sealed to the outside by means of O-ring seals. When opening the coupling, the adapter piece dissolves together with the screwed heating nozzle or cutting nozzle and is replaced automatically by means of the changing device.

The known device provides for an automated change of the nozzles of the cutting torch, wherein the cutting nozzle and the heating nozzle are replaced in conjunction with the adapter piece.

The adapter piece causes a comparatively high overall height in the known cutting torch and its production is associated with additional costs.

From the GB 1 023 354 A a welding torch is known, which has a cutting nozzle which is formed in the form of a slot nozzle and which is surrounded by a heating nozzle. The nozzles are substantially cylindrical. The heating nozzle is provided with a conical constriction, on which the cutting nozzle rests with a conical outer shell section. Both sides of this conical bearing surface both nozzles are cylindrical.

The production of such, conical contact surfaces in heating and cutting nozzle requires a lot of effort to maintain the necessary dimensional accuracy. In this context, it is mentioned that the contact surfaces can be obtained by chipless forming processes.

The US 3,053,312 A describes a cutting torch with a cylindrical cutting nozzle, which is designed as a slot nozzle, and which is surrounded by a heating nozzle with a substantially cylindrical inner bore. For a variable axial fixation of the components to each other, the cutting nozzle is provided at its upper end with a collar which rests on one on an upwardly facing step of the inner bore of the heating nozzle.

The present invention is therefore an object of the invention to provide a cutting torch - especially for a flame cutting machine - which allows easy and quick nozzle change, and at the same time characterized by simple and compact design, which goes hand in hand with easy maintenance, easy maintenance and cost-effective production , And in which, moreover, the cost of storing the wear parts is reduced.

In addition, the invention has for its object to provide a use of the cutting torch according to the invention with a nozzle system comprising nozzles for slow-burning fuel gases and for fast-burning fuel gases, and in which the cost of storing the wear parts and the nozzle change is reduced.

With regard to the cutting torch, this object is achieved on the basis of the above-mentioned cutting torch according to the invention in that the circumferential edge of the bearing surface is formed as an outer terminating edge of a support surface extending perpendicularly to the central axis.

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 a "lower 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 lower outer cylinder of the cutting nozzle with little radial clearance. On the one hand, this leads to the fact that the cutting nozzle and the heating nozzle can be detached from the burner head separately and without the risk of damaging passport or contact surfaces, 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 are also axially fixed to each other - without mechanical connection between the cutting nozzle and the heating nozzle. A positive connection or a frictional metallic connection - as the interference fit between the heating nozzle and cutting nozzle in the aforementioned known cutting torch - is not required, so that the nozzle change in the cutting torch invention is facilitated overall.

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 lower outer cylinder of the cutting nozzle. The length of the lower outer cylinder is precisely adjustable without much production effort; a complex adaptation of inner cone and outer cone to each other is not required in the cutting torch invention. When changing the combustion gases of 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 the same time an exchange of the heating nozzle is required. The heating nozzle is suitable for use with any of the nozzle nozzle cutting nozzles and can be maintained even when the cutting nozzle is replaced. 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.

The extended application possibilities of the cutting torch according to the invention also contributes to the fact that larger and more variable working distances between the nozzle and the workpiece surface are possible with the cylindrical nozzle form-in comparison with conical nozzles. typically around 15 to 20 mm.

The cutting torch according to the invention may be both a burner with external ignition and a burner with internal electrical ignition.

The axial fixation of the cutting nozzle and the heating nozzle to each other results in the cutting torch according to the invention characterized in that the cutting nozzle is supported with its support surface on the support surface of the heating nozzle. In this case, the support surface on a radially encircling edge, which rests on the support surface.

By means of an edge, a particularly defined and always reproducible axial fixation of cutting nozzle and heating nozzle is achieved. The edge is formed as a surface perpendicular to the central axis (rectangular step). It can be made simpler and more accurate, so that the peripheral edge is formed as an outer end edge of a perpendicular to the central axis extending support surface. The support surface always runs parallel to the support surface.

It has proven to be particularly advantageous if the cutting nozzle is provided with a funnel-shaped inlet for the cutting oxygen line. As a result, the degree of turbulence of the cutting oxygen as it enters the cutting nozzle is reduced and thus the reproducibility of the mode of operation, in particular after a nozzle change, is improved.

In a particularly preferred embodiment of the cutting torch according to the invention the outer jacket of the cutting nozzle upstream of the support surface is designed as an upper outer cylinder, the cylinder jacket surface provided with a sealing ring sealingly abuts a cutting nozzle receiving the burner head into which the cutting nozzle protrudes.

An adapter piece - as in the known cutting torch mentioned above - is not required, since the cutting nozzle is directly connected to the burner head. As a result, a lower height is possible and eliminates the manufacturing cost of the adapter piece.

In addition, the described recording of the cutting nozzle in the burner head facilitates their replacement. By means of the sealing ring, the cutting oxygen line is sealed to the outside and at the same time Cutting nozzle 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 pressing into the cutting nozzle receptacle. This type of mounting the cutting nozzle requires little effort when changing the nozzle, as can be dispensed with a mechanical connection of the cutting nozzle to the burner head. In addition, an improved compared to a metallic seal via thread or cone, safer tightness is achieved.

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

The outer jacket of the cutting nozzle is cylindrical both in the longitudinal section between its bearing surface and the nozzle outlet ("lower outer cylinder") and in the longitudinal section between the bearing surface and the upper end ("upper outer cylinder"). Due to its cylindrical shape, the cutting nozzle of the cutting torch according to the invention is particularly easy to manufacture.

It has proven particularly useful if the length of the upper outer cylinder is between 25 mm and 35 mm.

This measure results in a comparatively short length of the cutting nozzle, which facilitates a compact design of the cutting torch. Contributes in particular also when the cutting nozzle by means of sealing ring - as described above - is held in the burner head, and not - as usual - by means of threaded connection or pressure screw.

A further improvement results when the cutting nozzle is held in the cutting nozzle receptacle with axial play. The cutting nozzle is merely radially fixed in the receptacle, while dispensing with an axial stop position in the direction of the central axis. The axial clearance dimensional tolerances are intercepted in the length of the cutting nozzle, so that they have neither an effect on the outer dimensions of the cutting torch, nor to 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 cutting nozzle receptacle.

The large quantities of heat generated during the autogenous cutting in the front region of the nozzles must be removed as quickly as possible in order to avoid damage to the nozzles and to reduce wear. There are therefore used metallic nozzle body with high thermal conductivity. The sealing ring in the upper area of the cutting nozzle must therefore withstand high temperatures. It has therefore proven to be advantageous if cutting nozzle consists of a metal body which is provided in the region of the adjacent sealing ring with a ceramic layer.

The sealing ring rests on a ceramic layer with poor thermal conductivity and is therefore shielded from the heat transported in the metal body and therefore less thermally stressed.

The ceramic layer can be designed as a separate, gas-tight connected to the metal body component. However, the ceramic layer is preferably produced by coating, wherein it has a thickness in the range between 5 μm and 25 μm. By coating method, the production of a tight connection between the metal body and the ceramic layer is simplified.

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 mentioned distance limit values result as a compromise between the requirements on the one hand of a sufficient radial Guiding the cutting nozzle in the "inner cylinder" of the heating nozzle, and on the other hand a low overall height to provide a compact cutting torch as possible.

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 sealingly engages a heating nozzle receptacle formed in the burner head, into which the heating nozzle protrudes.

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 to be advantageous, there are mentioned advantages in terms of a low cost in nozzle replacement and improved tightness.

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 the outer collar 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. To the another allows a clutch - especially a quick release coupling - a particularly simple and quick release and mounting the nozzles on the burner head. For this purpose, the coupling is on the one hand releasably attached to the burner head and on the other hand it engages under the outer collar of the heating nozzle, and fixed their position to the burner head.

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 play-free, manufacturing tolerances of the heating nozzle compensating fixation of the heating nozzle on the burner head is 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 down and, after prevented above. The two components - heating nozzle and clutch - but can be pulled apart against the resistance of the O-ring.

A particularly suitable embodiment of the invention with regard to the overall height and the compact design of the cutting torch is that the burner head surrounds the cutting nozzle receptacle coaxially surrounded by an annular gap-shaped heating nozzle receptacle in which the upper end of the heating nozzle is sealed against the atmosphere, has. The nozzles are held directly on the burner head; Intermediate pieces are avoided.

In this case, an embodiment has proved to be particularly favorable, in which the cutting nozzle recording has an inner wall with an internal thread and a first radially encircling, metallic sealing surface for sealingly receiving an externally threaded and applied to the first sealing surface cutting nozzle, and wherein the Inner wall 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 is in this case equipped with at least two different elements for the production of the connection with a projecting into the first receptacle cutting nozzle. One of the elements is an internal thread, which corresponds to an external thread of the cutting nozzle, wherein usually a seal is generated to the outside by the contact force generated during screwing between abutting contact surfaces. The other element is a radially encircling 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 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 or as an alternative to this embodiment of the cutting torch according to the invention, it has also proven useful if the heating nozzle receptacle has an inner wall 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 against the first sealing surface has, and when the inner wall is provided with a second radially encircling sealing surface for sealingly receiving a heating nozzle with a voltage applied to the second sealing surface sealing ring. In this embodiment, the same advantageous result for the sealing support of the heating nozzle on the burner head Effects on the flexibility of the burner head insert, as previously explained for the cutting nozzle.

The nozzles of the cutting torch according to the invention are usually made of stainless steel, brass or a temperature-resistant copper alloy. The heating nozzle can also consist of ceramic. Especially with these 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, such as, for example, CrN, TiN, TiC, WC, are suitable as the hard material layer.

With regard to the use of the cutting torch with a nozzle system for slow burning and fast burning gases (in combination with oxygen) according to the present invention, the technical problem mentioned above is achieved according to the invention, by a downstream of the support surface cylindrically shaped heating nozzle and a plurality of interchangeable, each for a Fuel gas designed, downstream of the support surface cylinder-shaped cutting nozzles, all cutting nozzles between the upper end and support surface an upper outer cylinder equal part length, and between support surface and nozzle outlet a lower outer cylinder having a tuned to the respective fuel gas partial length, such that at on the support surface resting support surface sets a predetermined depending on the respective fuel gas axial distance between the nozzle outlet of the cutting nozzle and the nozzle outlet of the heating nozzle.

The cylindrical design of the heating nozzle (inner cylinder) and the cutting nozzle (lower outer cylinder) in the region of the respective lower end are a prerequisite for the nozzle system. Another prerequisite is that the inner cylinder of the heating nozzle serves as a radial guide of the lower outer cylinder of the cutting nozzle, as explained in more detail above with reference to the description of the cutting torch according to the invention.

Because the fact that the Heizdüse the lower outer cylinder of the cutting nozzle leads - that surrounds with little radial clearance - a change of the cutting nozzle is made possible without great effort and without the risk of damaging passport or contact surfaces. The cylindrical design of the heating nozzle in the region of its "inner cylinder" makes it suitable for use with different cutting nozzles, for example, cutting nozzles for slow-burning fuel gases or for fast-burning fuel gases. However, with the proviso that the cutting nozzles have a corresponding cylindrical formation in the region of their "lower outer cylinder" and beyond between the upper end and support surface of equal length.

The same length of each die nozzle nozzle ensures that each die fits exactly to the configuration specified by the torch head and heater nozzle.

The partial length between support surface and nozzle outlet corresponds to the length of the "lower outer cylinder". This length depends on the area of use of the respective cutting nozzle, which is characterized in particular by the nature of the fuel gas. Because of the length of the lower outer cylinder, the axial distance between the nozzle outlet of the cutting nozzle and the nozzle outlet of the heating nozzle is specified. This is lower for a fast-burning fuel gas than for a slow-burning fuel gas. The "nozzle exit" runs in the plane of the lower edge of the respective nozzle.

The length of the lower outer cylinder is precisely adjustable without much production effort; a complex adaptation of inner cone and outer cone to each other is not required. The nozzle system according to the invention is characterized in that when changing the type of fuel gas, the previous cutting nozzle to 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 nozzle nozzle cutting nozzles and can be maintained even when the cutting nozzle is replaced. This reduces the variety of heating nozzle shapes to be stored, simplifies the storage and improves the safety of the rest of the rest cutting torch according to the invention by avoiding combinations of unsuitable nozzles.

With regard to a flexible use of the cutting torch and a low cost for the nozzle production and storage, a nozzle system has proven particularly useful, with cutting nozzles in which the partial length of the lower outer cylinder between 6 mm and 10 mm, wherein the length of the upper outer cylinder in Range between 25 mm and 30 mm, and in which the partial length of the lower outer cylinder is selected depending on the respective fuel gas and / or the power range such that when resting on the support surface an axial distance between the nozzle outlet of the cutting nozzle and the nozzle exit the heating nozzle in the range between 0 mm and 3 mm results.

Further improvements of the nozzle system result from embodiments of the cutting nozzles with the features of claims to 3, 5, 7 and 8. Reference is made to the corresponding explanations of the cutting torch according to the invention.

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.

FIG. 4 shows a first embodiment of a mounted cutting torch according to the invention. This is part of a flame cutting machine for oxy-fuel 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 based on the FIGS. 1 to 3 and the assembly drawing according to FIG. 4 explained in more detail.

The cutting nozzle 2 according to FIG. 1 consists of a about the central axis 15 rotationally symmetrical, substantially cylindrical brass part, which 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 FIG. 4 ).

At the upper end of the cutting nozzle 2, the outer shell has a circumferential groove suitable for receiving an O-ring 9 made of a refractory material, e.g. Silicone, is provided.

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 pipe 11 is sealed to the outside and at the same time the cutting nozzle 2 within an inner bore 30 of the burner head 1 (FIG. FIG. 4 ) fixed radially. 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 support step 16 of the heating nozzle 3 (see FIG. 4 ), which is ensured by the acting on the upper end face 10 cutting oxygen pressure. 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

In the FIG. 2 shown Heizdüse 3 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 for receiving a cutting nozzle 2 according to FIG. 1 suitable. 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 step 5 ( FIG. 4 ). The through hole 17 is formed below the support step 16 cylindrically with an inner diameter of slightly more than 6 mm. 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 bears on the inner wall of an annular groove 33 in the burner head 1 ( FIG. 4 ).

By means of the O-ring 21, the supply line 26 (see FIG. 4 ) is sealed for the fuel-oxygen mixture to 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 abuts in the assembled cutting torch against a downwardly directed annular surface of the burner head 1 (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.

In order to facilitate a nozzle change, a loose connection is generated between the heating nozzle 3 and clutch 4, which prevents slipping out of the heating nozzle 3 from the inner bore of the clutch 4 both down and up when loosening the clutch 4 from the burner head 1. For this purpose, a Umfangseinfräsung 23 is provided on the outer surface of the heating nozzle 3 below the outer collar 22, in which an O-ring 29 is inserted, the - like FIG. 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 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 attached ( FIG. 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 based FIG. 1 described). For the axial fixation of the cutting nozzle 2 with O-ring 9 am Burner head 1 is provided in the region below the internal thread 31 has a cross-sectional constriction at which the end face of the cutting nozzle 2 in the installed state is applied (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 this additionally with an internal thread 34. Thus, the burner head 1 is suitable both for receiving a heating nozzle with an internal thread 34 matching external thread as well as for sealingly receiving a heating nozzle. 3 , which is provided with a voltage applied to the sealing surface 35 O-ring 21 (as above based FIG. 2 described). The outer collar 22 of the heating nozzle 3 serves for the axial fixation of the heating nozzle 3 on the burner head 1 by the upper side abuts in the mounted cutting torch against an end face annular surface 36 of the burner head 1 (see FIG. 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 according to FIG. 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 basis FIG. 2 described heating nozzle 3 is suitable both for the inclusion of cutting nozzles for fast-burning fuel gases as well as for the inclusion of cutting nozzles for slow-burning fuel gases. This is in the FIGS. 5a and 5b shown.

The cylindrical design of the heating nozzle 3 (see FIG. 2 ) in the region of the inner cylinder 18 makes this suitable for use with different cutting nozzles. For this purpose, however, it is necessary that the cutting nozzles have a corresponding cylindrical formation in the region of the outer cylinder 7 (FIG. FIG. 1 ) and furthermore in the upper upstream side portion 6 have the same part length. This is at the cutting nozzles 2a ( FIG. 5a ) and 2b ( FIG. 5b ) the case. 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 nozzle nozzle cutting nozzles and can be maintained even when the cutting nozzle is replaced. 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 opposite the in FIG. 4 shown ball trap 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 numerals as in the case of FIGS. 1 to 4 and 5a and 5b are used, so are the same or equivalent components and components 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 clarity, the connecting line for the fuel gas-oxygen mixture in FIG. 6 not shown.

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 is connected to a cutting nozzle 2, and with a heating nozzle 3 embracing the cutting nozzle 2 by means of a coupling 61 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 in an in FIG. 6 schematically indicated connecting groove 64 introduced to the milled recess 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 variation on the basis FIG. 1 described cutting nozzle 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. The ceramic layer 66 reduces the heat conduction to the O-ring 9 and thus improves the long-term stability of the seal.

Claims (18)

1. A flame cutter comprising a burner head (1) which includes a central axis (15) and has connected thereto a metallic cutting nozzle (2), including an axial cutting oxygen line, which is encompassed in the form of a cap by a heating nozzle (3) having an axial through-bore (17), the cutting nozzle having an outer covering provided with circumferentially distributed longitudinal slots (8) extending from the lower downstream end of the cutting nozzle over a cross-sectional enlargement which is provided upstream thereof and forms a radially surrounding bearing surface (5), and wherein the heating nozzle is provided in the area between its upper upstream end and its nozzle exit (13) with a cross-sectional constriction which forms a radially surrounding upstream support surface (16) and on which the cutting nozzle abuts with its bearing surface (5), wherein the outer covering of the cutting nozzle (2) is configured as a lower outer cylinder (7) downstream of the bearing surface (5) and the through bore (17) of the heating nozzle (3) is cylindrical downstream of the support surface (16) and is configured as a radial guide for the lower outer cylinder (7), wherein the bearing surface (5) comprises a radially surrounding edge (25) which abuts on the support surface (16), characterized in that the surrounding edge (25) is formed as an outer terminal edge of a bearing surface (5) extending in a direction perpendicular to the central axis (15).
2. The flame cutter according to claim 1, characterized in that the cutting nozzle (2) is provided with a funnel-shaped inlet (26) for the cutting oxygen line (11).
3. The flame cutter according to claim 1 or 2, characterized in that the outer covering of the cutting nozzle (2) is formed upstream of the bearing surface (5) as an upper outer cylinder (6) having a cylindrical covering surface which, provided with a sealing ring (9), sealingly abuts on a cutting-nozzle receiving means (30) of the burner head (1) into which the cutting nozzle (2) projects.
4. The flame cutter according to claim 3, characterized in that the cutting nozzle (2) is held in the cutting-nozzle receiving means (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 on its upper end with an outer edge (10) rounded on the face.
6. The flame cutter according to any one of the preceding claims, 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.
7. The flame cutter according to any one of the preceding claims, characterized in that the cutting nozzle consists of a metal body which in the area of the abutting sealing ring (9) is provided with a ceramic layer.
8. The flame cutter according to claim 7, characterized in that the ceramic layer has a thickness in the range between 5 µm and 25 µm and is formed by way of coating.
9. The flame cutter according to any one of the preceding claims, characterized in that the heating nozzle (3) comprises an outer covering which is provided on the upper end with a sealing ring (21) which sealingly abuts on a heating-nozzle receiving means (33) which is formed in the burner head (1) and into which the heating nozzle (3) projects, wherein the outer covering of the heating nozzle (3) is provided downstream of the sealing ring (21) with an outer collar (22) which with an upstream ring surface abuts on a ring surface (36) of the burner head (1) at the face side.
10. The flame cutter according to claim 9, characterized in that the heating nozzle (3) is detachably fixed to the burner head (1) by means of a coupling (4; 61) acting on the outer covering of the heating nozzle (3), the coupling (4; 61) comprising an inner through-bore with a radial cross-sectional constriction (42) that grips under the outer collar (22) of the heating nozzle (3).
11. The flame cutter according to claim 9 or 10, characterized in that the outer covering of the heating nozzle (3) is provided with a lower sealing ring (38) abutting downstream on the outer collar (22).
12. The flame cutter according to any one of claims 10 to 11, 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 provided downstream of the cross-sectional constriction (42) in the inner bore of the coupling (4; 61).
13. The flame cutter according to any one of the preceding claims, characterized in that the cutting-nozzle receiving means (30) is coaxially encompassed by a heating-nozzle receiving means (33) shaped as an annular gap, in which the upper end of the heating nozzle (3) is received sealingly to the outside.
14. The flame cutter according to claim 13, characterized in that the cutting-nozzle receiving means (30) comprises an inner wall with an internal thread (31) and a first radially surrounding metallic sealing surface for sealingly receiving a cutting nozzle which is provided with an external thread and abuts on the first sealing surface, and that the inner wall is provided with a second radially surrounding sealing surface (32) for sealingly receiving a cutting nozzle (2) with a sealing ring (9) abutting on the second sealing surface.
15. The flame cutter according to claim 12 or 13, characterized in that the heating-nozzle receiving means (33) comprises an inner wall with an internal thread (34) and a first radial metallic sealing surface for sealingly receiving a heating nozzle which is provided with an external thread and abuts on the first sealing surface, and that the inner wall is provided with a radially surrounding sealing surface (35) for sealingly receiving a heating nozzle (3) with a sealing ring (32) abutting on the second sealing surface (35).
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.
17. Use of a flame cutter according to any one of the preceding claims with a nozzle system for slowly combustible and quickly combustible gases, characterized by a heating nozzle (3) which is cylindrically shaped downstream of the support surface (16) and a plurality of exchangeable cutting nozzles (2a; 2b) which are designed for a respective combustion gas and cylindrically shaped downstream of the bearing surface (5), wherein the cutting nozzles (2a, 3b) between upper end and bearing surface (5) have an upper outer cylinder (6) of the same length and a lower outer cylinder (7) between bearing surface (5) and nozzle exit (13) with a partial length matching the respective combustion gas, in such a manner that, when the bearing surface (5) is abutting on the support surface (16), an axial distance (50) which is predetermined in response to the respective combustion gas is set between the nozzle exit (13) of the cutting nozzle (2) and the nozzle exit (14) of the heating nozzle (3).
18. Use according to claim 17, characterized in that the partial length of the lower outer cylinder (7) is between 6 mm and 10 mm, that the length of the upper outer cylinder (6) is in the range between 25 mm and 30 mm, and that the partial length of the lower outer cylinder (7) is chosen in response to the respective combustion gas and/or the performance range such that, when the bearing surface (5) is abutting on the support surface (16), an axial distance (50) is obtained between the nozzle exit (13) of the cutting nozzle (2) and the nozzle exit (15) of the heating nozzle (3) in the range between 0 mm and 3 mm.

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