BR112015028734B1 - Insulating part of one or more parts for a plasma arc torch, in particular a plasma cutting torch and plasma torches and arrangements having the same - Google Patents

Abstract

SINGLE OR MULTI-PART INSULATION COMPONENT FOR A PLASMA TORCH, PARTICULARLY A PLASMA CUTTING TORCH, AND PLASMA ARRANGEMENTS AND TORCHES HAVING THE SAME. The invention relates to a one-part or multi-part insulating component for a plasma torch, particularly a plasma cutting torch, for electrical isolation between at least two electrically conductive components of the plasma torch, characterized in that the Insulating component consists of an electrically non-conductive material and a readily thermally conductive material, or at least a portion thereof consists of an electrically non-conductive material and an readily thermally conductive material. The invention further relates to arrangements and plasma torches having the same, and to a method for processing plasma cutting and plasma welding.

Description

[0001] The present invention relates to an insulating piece of one or more parts for a plasma arc torch, in particular a plasma cutting torch, for electrical isolation between at least two electrically conductive components of the plasma torch, the arrangements and plasma torches having such an insulating part, to plasma torches having such an arrangement, and to a method for machining an operating part with a thermal plasma, for plasma cutting and for plasma welding.

[0002] Plasma torches are very commonly used for the thermal machining of electrically conductive materials such as steel and non-ferrous metals. In this case, plasma welding torches for welding, and plasma cutting torches for cutting electrically conductive materials, such as steel and non-ferrous metals, are used. Plasma torches usually consist of a torch body, an electrode, a nozzle, and a retainer for the same. Modern plasma torches additionally have a protective nozzle cover seated over the nozzle. Often, a mouthpiece is secured by means of a mouthpiece cap.

[0003] The components that become worn during plasma torch operation due to the high thermal load produced by the arc are, depending on the type of plasma torch, in particular, the electrode, the nozzle, the nozzle cover, the nozzle protective cap, the nozzle protective cap retainer, and the plasma gas transport part and secondary gas transport part. These components can be easily changed by an operator and thus referred to as wearing parts.

[0004] Plasma torches are connected via lines to a power source and a gas supply that supplies the plasma torch. In addition, the plasma torch can be connected to a cooling device by a cooling medium, for example, a coolant.

[0005] Particularly high thermal loads occur on plasma cutting torches. These are caused by the large constriction of the plasma jet by the nozzle hole. Here, in contrast to plasma welding, small holes are used with respect to cutting current so that high current densities of 50 to 150 A/mm2 in the nozzle hole, high energy densities of about 2x106 W/cm2, and high temperatures of up to 30 000 K are generated. In addition, relatively high gas pressures, typically up to 12 bar, are used in the plasma cutting torch. The combination of high temperature and high kinetic energy of the plasma gas flowing through the nozzle bore results in the operating part melting and the molten material being fired. A cut is produced, and the operating part is separated. In plasma cutting, use is often also made of oxidizing gases in order to cut non-alloy steels. This additionally leads to a high thermal load on the wear parts and the plasma cutting torch.

[0006] The plasma cutting torch will be discussed in particular below.

[0007] A plasma gas flows between the electrode and the nozzle. Plasma gas is transported by a gas transport part, which may also be a multipart part. In this way, the plasma gas can be directed in a directed manner. It is often seated in rotation on the electrode by a radial and/or axial deviation of the openings in the plasma gas transport part. The plasma gas transport part consists of electrically insulating material, as the electrode and nozzle have to be electrically insulated from each other. This is necessary as the electrode and nozzle have different electrical potentials during plasma cutting torch operation. In order to operate the plasma cutting torch, an arc, which ionizes the plasma gas, is generated between the electrode and the nozzle and/or the operating part. In order to strike the arc, a high voltage may be applied between the electrode and nozzle, said high voltage ensuring that the section between the electrode and nozzle is pre-ionized and thereby an arc is formed. The burning of the arc between the electrode and the nozzle is also referred to as a pilot arc.

[0008] The pilot arc exits through the nozzle hole and meets the operating part, and ionizes the section to the operating part. In this way, an arc can form between the electrode and the workpiece. This bow is also referred to as the main bow. During the main arc, the pilot arc can be turned off. However, it can also continue to operate. During plasma cutting, it is often turned off so as not to additionally load the nozzle.

[0009] In particular, the electrode and the nozzle are subjected to high thermal stresses and have to be cooled. At the same time, they also have to carry the electric current that is required to form the arc. Therefore, materials with good thermal conductivity and good electrical conductivity, generally metals, eg copper, silver, aluminum, tin, zinc, iron or alloys, in which at least one of these metals is contained, are used for this.

[0010] The electrode often consists of an electrode holder and an emission insert that is produced from a material that has a high melting point (>2000°C), and a lower electron operating function than the electrode holder. When non-oxidizing plasma gases, for example, argon, hydrogen, nitrogen, helium, and mixtures thereof, are used, tungsten is used as the material for the emission insert, and when oxidizing gases, for example, oxygen, air, and mixtures of these, nitrogen/oxygen mixture and mixtures with other gases, are used, hafnium or zirconia are used as materials for the emission insert. The high temperature material can be seated in an electrode holder which consists of material with good thermal conductivity and good electrical conductivity, eg pressed in with a shape coupling and/or force coupling.

[0011] The electrode and nozzle can be gas cooled, eg plasma gas or a secondary gas flowing along the outside of the nozzle. However, cooling with a liquid, eg water, is more effective. In this case, the electrode and/or the nozzle are often cooled directly with the liquid, ie the liquid is in direct contact with the electrode and/or the nozzle. In order to guide the coolant around the nozzle, a nozzle cap is located around the nozzle, the inner face of said nozzle cap forming with the outer face of the nozzle a coolant space in which the coolant flows.

[0012] On modern plasma cutting torches, a protective shield cap is additionally located outside the shield and/or shield cap. The inner face of the mouthpiece protective cap and the outside face of the mouthpiece or mouthpiece cap form a space through which a secondary gas or protective gas flows. The secondary or shielding gases exit the hole in the protective cap of the nozzle and enclose the plasma jet, and ensure a defined atmosphere around the latter. In addition, the secondary gas protects the nozzle and nozzle protective cover from arcs that can form between them and the operating part. These are referred to as double arcs, and can result in damage to the mouthpiece. In particular when piercing the operating part, the nozzle and the nozzle protective cap are highly stressed by the splashing of hot material. Secondary gas, the volumetric flow of which can be increased during drilling compared to the value during cutting, keeps material splashing away from the nozzle and nozzle protective cap and thereby protects them from damage.

[0013] The protective cap of the mouthpiece is likewise subjected to high thermal stress, and has to be cooled down. Therefore, materials with good thermal conductivity and good electrical conductivity, usually metals, for example copper, silver, aluminum, tin, zinc, iron or alloys, in which at least one of these metals is contained, are used for this.

[0014] However, the electrode and nozzle can also be cooled indirectly. In this case, they are in touch contact with a component consisting of a material with good thermal conductivity and good electrical conductivity, usually a metal, e.g. copper, silver, aluminum, tin, zinc, iron or alloys, in which at least one of these metals is contained. This component is, in turn, directly cooled, that is, it is in direct contact with the usually flowing refrigerant. These components can simultaneously serve as a retainer or receptacle for the electrode, mouthpiece, mouthpiece cap, or mouthpiece protective cap, and dissipate heat and supply power.

[0015] It is also possible that only the electrode or only the nozzle is cooled with liquid. It is precisely in this case that excessive temperatures often occur in the single gas-cooled component, which then quickly becomes worn out, or is even destroyed. This also results in high temperature differences between components in the plasma cutting torch, and, as a result, additional mechanical stresses and stresses.

[0016] The protective cap of the nozzle is usually cooled only by the secondary gas. Arrangements in which the protective cap of the mouthpiece is cooled directly or indirectly by a coolant are also known.

[0017] Gas cooling (plasma gas and/or secondary gas cooling) has the problem that it is not effective to achieve acceptable cooling or heat dissipation, and the required volumetric gas flow is too high for this proposal . Water-cooled plasma cutting torches require, for example, volumetric gas flows from 500 l/h to 4000 l/h, while non-water-cooled plasma cutting torches require volumetric gas flows from 5000 to 11,000 l /H. These ranges occur depending on the cutting currents used, which can be, for example, in a range of 20 to 600 A. At the same time, the volumetric flow of plasma gas and/or secondary gas must be selected such that the best cutting results are achieved. Excessive volumetric flows, which are required for cooling, however, often impair the cutting result.

[0018] In addition, the high gas consumption provided by high volumetric flows is uneconomical. This particularly applies when gases other than air, eg argon, nitrogen, hydrogen, oxygen or helium, are used.

[0019] The use of direct water cooling for all wear parts is, by contrast, very effective, but results in an increase in plasma cutting torch dimensions, as, for example, cooling channels are required for transporting the coolant to the wear parts to be cooled and away from them again. In addition, when the directly liquid-cooled wear parts are changed, great care is required, as less coolant as possible must remain between the wear parts in the plasma cutting torch, as this can result in damage to the plasma cutting torch. plasma torch when the arc is struck.

[0020] Therefore, the invention is based on the objective of ensuring more effective cooling of the components, in particular, wearing parts, of a plasma torch.

[0021] According to a first aspect, this objective is achieved by an insulating piece of one or more parts for a plasma arc torch, in particular a plasma cutting torch, for electrical isolation between at least two electrically conductive components of the plasma torch, characterized in that it consists of an electrically non-conductive material with good thermal conductivity or at least a part of it consists of an electrically non-conductive material with good thermal conductivity. Here, the expression "electrically non-conductive" is also intended to mean that the insulating piece of material in the plasma torch conducts electricity to a lesser or negligible extent. The insulating part may be, for example, a plasma gas transport part, a secondary gas transport part, or a cooling gas transport part.

[0022] Furthermore, according to a second aspect, this objective is achieved by an arrangement comprising a plasma arc torch electrode and/or a nozzle, and/or a nozzle cap, and/or a protective cap. nozzle, and/or a nozzle protective cap retainer for a plasma torch, in particular a plasma cutting torch, and an insulating part according to any one of claims 1 to 12.

[0023] According to a third aspect, this objective is achieved by an arrangement composed of a receptacle for a protective nozzle cap retainer, and of a protective nozzle cap retainer for a plasma torch, in particular a torch cutting device, characterized in that the receptacle is configured as an insulating piece according to any one of claims 1 to 12, which is preferably in direct contact with the protective cap retainer of the nozzle. For example, the receptacle and the mouthpiece protective cap retainer can be threaded together.

[0024] According to an additional aspect, this objective is achieved by an arrangement composed of a plasma arc torch electrode and a nozzle for a plasma torch, in particular, a plasma cutting torch, characterized in that that an insulating part according to any one of claims 1 to 12, which is configured as a plasma gas transport part, is arranged between the electrode of the plasma arc torch and the nozzle, preferably in direct contact therewith.

[0025] Furthermore, according to a further aspect, this objective is achieved by an arrangement composed of a nozzle and a protective nozzle cover for a plasma torch, in particular a plasma cutting torch, characterized by the fact that an insulating part according to any one of claims 1 to 12, which is configured as a secondary gas transport part, is arranged between the nozzle and the protective cap of the nozzle, preferably in direct contact therewith.

[0026] Furthermore, according to the additional aspect, this objective is achieved by an arrangement composed of a nozzle cover and a protective nozzle cover for a plasma torch, in particular a plasma cutting torch, characterized in that an insulating part according to any one of claims 1 to 12, which is configured as a secondary gas transport part, is arranged between the nozzle cap and the protective cap of the nozzle, preferably in direct contact with these.

[0027] Furthermore, the present invention provides a plasma torch, in particular a plasma cutting torch, comprising at least one insulating piece according to any one of claims 1 to 12.

[0028] Furthermore, the present invention provides a plasma torch, in particular a plasma cutting torch, comprising at least one arrangement according to any one of claims 13 to 18, and a method according to claim 24 .

[0029] In the case of the insulating part, provision may be made for it to consist of at least two parts, in which one of the parts consists of an electrically non-conductive material with good thermal conductivity, and the other or at least one other of the parts consists of an electrically non-conductive material and a thermally non-conductive material.

[0030] In particular, provision may be made here for the part consisting of an electrically non-conductive material with good thermal conductivity to have at least one surface functioning as a contact face, said surface being aligned with or projecting in addition to an immediately adjacent surface of the part consisting of an electrically non-conductive material and a thermally non-conductive material.

[0031] According to a particular embodiment, the insulating part consists of at least two parts, in which one of the parts consists of a material with good electrical conductivity and good thermal conductivity, and the other or at least one other of the parts consists of an electrically non-conductive material with good thermal conductivity.

[0032] In a further embodiment of the invention, the insulating part consists of at least three parts, in which one of the parts consists of a material with good electrical conductivity and good thermal conductivity, the other of the parts consists of an electrically non-electrical material. -conductive with good thermal conductivity, and an additional one of the parts consists of an electrically non-conductive material and a thermally non-conductive material.

[0033] Advantageously, the electrically non-conductive material with good thermal conductivity has a thermal conductivity of at least 40 W/(m*K), preferably at least 60 W/(m*K), and further more preferably at least 90 W/(m*K), even more preferably at least 120 W/(m*K), even more preferably at least 150 W/(m*K), and still more preferably at least 180 W/(m*K).

[0034] Appropriately, electrically non-conductive material with good thermal conductivity, and/or electrically non-conductive material and thermally non-conductive material, have an electrical resistivity of at least 106 Q*cm, preferably , at least 1010 Q*cm, and/or electrical resistance of at least 7 kV/mm, preferably at least 10 kV/mm.

[0035] Advantageously, the electrically non-conductive material with good thermal conductivity is a ceramic, preferably from the group of nitride ceramics, in particular aluminum nitride ceramics, boron nitride ceramics, and silicon nitride, carbide ceramics, in particular, silicon carbide ceramics, oxide ceramics, in particular, aluminum oxide ceramics, zirconium oxide ceramics, and beryllium oxide ceramics, and silicate ceramics, or is a plastic material, for example plastic film.

[0036] It is also possible to use a combination of an electrically non-conductive material with good thermal conductivity, e.g. ceramic, and some other electrically non-conductive material, e.g. plastic material, in what is referred to as a composite material. . Such a composite material can be produced, for example, from powder of both materials by sintering. Finally, this composite material must be electrically non-conductive, and have good thermal conductivity.

[0037] According to a particular embodiment of the invention, electrically non-conductive material and thermally non-conductive material have a thermal conductivity of at most 1 W/(m*K).

[0038] Advantageously, the parts are connected together in a form coupling manner, or force coupling, by adhesive bonding, or by a thermal method, for example, brazing or soldering.

[0039] In a particular embodiment of the invention, the insulating piece has at least one opening and/or at least one cut and/or at least one groove. This may be the case, for example, when the insulating part is a gas transport part, for example a plasma gas transport part or a secondary gas transport part.

[0040] In particular, provision can be made for the at least one opening and/or the at least one cut and/or the at least one groove to be located in the electrically non-conductive material with good thermal conductivity, and/or in the electrically non-conductive material and thermally non-conductive material, and/or in material with good electrical conductivity and good thermal conductivity.

[0041] In a further particular embodiment of the invention, the insulating piece is designed to carry a gas, in particular, a plasma gas, secondary gas, or cooling gas.

[0042] In the arrangement according to claim 13, provision may be made so that the insulating piece is in direct contact with the plasma arc torch electrode and/or the nozzle and/or the nozzle cap and/or the cap nozzle guard and/or the nozzle guard retainer.

[0043] Advantageously, the insulating piece is connected to the electrode of the plasma arc torch and/or the nozzle and/or the nozzle cover and/or the protective shield cap and/or the protective shield retainer of the nozzle in a manner coupling by shape and/or coupling by force, by adhesive bonding, or by a thermal method, for example brazing or soldering.

[0044] In a particular embodiment of the plasma torch according to claim 19, the insulating part, or a part thereof consisting of an electrically non-conductive material with good thermal conductivity, has at least one surface, preferably two surfaces , functioning as a contacting face, said surface being in direct contact with at least one surface of a component with good electrical conductivity, in particular, a plasma arc torch electrode, nozzle, nozzle cap, protective nozzle cap, or Nozzle cap retainer of plasma torch.

[0045] In particular, provision can be made in this case for the insulating part, or a part thereof consisting of an electrically non-conductive material with good thermal conductivity to have at least two surfaces that function as contact faces, said surfaces being in direct contact with at least one surface of a component with good electrical conductivity, in particular, a plasma arc torch electrode, shield, shield cap, shield shield cap, or shield shield retainer, of the plasma torch , and with an additional surface of an additional component with good electrical conductivity of the plasma torch.

[0046] According to a particular embodiment, the insulating part is a gas transport part, in particular, a plasma gas transport part, secondary gas transport part, or cooling gas transport part.

[0047] Advantageously, the insulating piece has at least one surface that is in direct contact with a cooling medium, preferably a liquid and/or a gas and/or a liquid/gas mixture, during operation.

[0048] In the method according to claim 24, provision can be made for a laser beam from a laser to be coupled to the plasma torch in addition to the plasma jet.

[0049] In particular, the laser may be a fiber laser, diode laser, and/or diode pumped laser.

[0050] The invention is based on the surprising discovery that, by using a material that is not only electrically non-conductive, but also has good heat conductivity, more effective and cost-effective cooling is possible, and smaller designs and simpler plasma torches are possible, and smaller temperature differences, and thus lower mechanical stresses, can be achieved.

[0051] The invention provides, at least in one or more particular embodiments, cooling of components, in particular wear parts, of a plasma torch that is more effective and/or cost effective, and/or results in lower mechanical stresses, and/or allow for smaller and/or simpler plasma torch designs, while at the same time ensuring electrical isolation between components of a plasma torch.

[0052] Additional features and advantages of the invention may be provided from the appended claims and the following description, in which a number of exemplary embodiments are described by way of the schematic drawings, in which:

[0053] Figure 1 shows a side view in partial longitudinal section of a plasma torch according to a first particular embodiment of the invention;

[0054] Figure 2 shows a side view in partial longitudinal section of a plasma torch according to a second particular embodiment of the invention;

[0055] Figure 3 shows a side view in partial longitudinal section of a plasma torch according to a third particular embodiment of the invention;

[0056] Figure 4 shows a partial longitudinal sectional side view of a plasma torch according to a fourth particular embodiment of the invention;

[0057] Figure 5 shows a side view in partial longitudinal section of a plasma torch according to a fifth particular embodiment of the invention;

[0058] Figure 6 shows a partial longitudinal sectional side view of a plasma torch according to a sixth particular embodiment of the invention;

[0059] Figure 7 shows a side view in partial longitudinal section of a plasma torch according to a seventh particular embodiment of the invention;

[0060] Figure 8 shows a partial longitudinal sectional side view of a plasma torch according to an eighth particular embodiment of the invention;

[0061] Figure 9 shows a side view in partial longitudinal section of a plasma torch according to a ninth particular embodiment of the invention;

[0062] Figures 10a and 10b show a longitudinal sectional view and a partially sectional side view of an insulating piece according to a particular embodiment of the invention;

[0063] Figures 11a and 11b show a longitudinal sectional view and a partially sectional side view of an insulating piece according to a further particular embodiment of the invention;

[0064] Figures 12a and 12b show a longitudinal sectional view and a partially sectional side view of an insulating piece according to a further particular embodiment of the invention;

[0065] Figures 13a and 13b show a longitudinal sectional view and a partially sectional side view of an insulating piece according to a further particular embodiment of the invention;

[0066] Figures 14a and 14b show a longitudinal sectional view and a partially sectional side view of an insulating piece according to a further particular embodiment of the invention;

[0067] Figures 14c and 14d show views as in figures 14a and 14b, but in which a part has been omitted;

[0068] Figures 15a and 15b show a plan view in partial section and a side view in partial section, respectively, of an insulating piece that is or can be used, for example, in the plasma torch in figures 6 to 9;

[0069] Figures 16a and 16b show a plan view in partial section and a side view in partial section, respectively, of an insulating piece that is or can be used, for example, in the plasma torch in figures 6 to 9;

[0070] Figures 17a and 17b show a plan view in partial section and a side view in partial section, respectively, of an insulating piece that is or can be used, for example, in the plasma torch in figures 6 to 9;

[0071] Figures 18a to 18d show a plan view in partial section and side views in section of an insulating piece according to a further particular embodiment of the present invention;

[0072] Figures 19a to 19d show sectional views of an arrangement composed of a mouthpiece and an insulating piece according to a particular embodiment of the invention;

[0073] Figures 20a to 20d show sectional views of an arrangement composed of a mouthpiece cap and an insulating piece according to a particular embodiment of the present invention;

[0074] Figures 21a to 21d show sectional views of an arrangement composed of a protective nozzle cap and an insulating piece according to a particular embodiment of the present invention;

[0075] Figures 22a and 22b show partial sectional views of an arrangement composed of a plasma arc torch electrode and an insulating piece according to a particular embodiment of the present invention; and

[0076] Figure 23 shows a side view in partial longitudinal section of an arrangement composed of a plasma arc torch electrode and an insulating piece according to a particular embodiment of the present invention.

[0077] Figure 1 shows a liquid cooled plasma cutting torch 1 according to a particular embodiment of the present invention. It comprises an electrode 2 of the plasma arc torch, an insulating part, configured as a plasma gas transport part 3, to transport PG plasma gas, and a nozzle 4. The electrode 2 of the plasma arc torch consists of a Plasma arc torch 2.1 electrode retainer and a 2.2 emission insert. The electrode retainer 2.2 of the plasma arc torch consists of a material with good electrical conductivity and good thermal conductivity, in this case of a metal, e.g. copper, silver, aluminum, or an alloy in which at least one of these metals is present. contained. The 2.2 emission insert is produced from a material that has a high melting point (>2000°C). In this case, when non-oxidizing plasma gases (e.g. argon, hydrogen, nitrogen, helium, and mixtures thereof) are used, tungsten is suitable, for example, and when oxidizing gases (e.g. oxygen, air, mixtures thereof , nitrogen/oxygen mixture) are used, hafnium or zirconia are suitable, for example. The 2.2 emission insert is inserted into the 2.1 electrode holder of the plasma arc torch. Electrode 2 of the plasma arc torch is illustrated here as a flat electrode where the emission insert 2.2 does not protrude beyond the front end surface of the electrode holder 2.1 of the plasma arc torch.

[0078] Electrode 2 of the plasma arc torch projects into the hollow interior space 4.2 of nozzle 4. The nozzle is screwed via a 4.20 thread into a nozzle retainer 6 with an internal thread 6.20. Arranged between the nozzle 4 and electrode 2 of the plasma arc torch is the plasma gas transport part 3. Located on the plasma gas transport part 3 are holes, openings, slots and/or cuts (not shown) through from which the PG plasma gas flows. By means of a corresponding arrangement, for example with a radial offset and/or an inclination of holes arranged radially with respect to the centerline M, the plasma gas PG can be set in rotation. This serves to stabilize the arc and plasma jet.

[0079] The arc burns between the 2.2 emission insert and an operating part (not shown), and is constrained by a hole in the 4.1 nozzle. The bow itself is already at a high temperature, which is further increased by its constriction. In this case, temperatures up to 30 000 K are indicated. For this reason, electrode 2 of the plasma arc torch and nozzle 4 are cooled by a cooling medium. A liquid, in the simplest case, water, a gas, in the simplest case, air, or a mixture thereof, in the simplest case, an air/water mixture, which is referred to as an aerosol, can be used as the medium. of cooling. Liquid cooling is the most effective. Located in an interior space 2.10 of electrode 2 of the plasma arc torch is a cooling tube 10 through which refrigerant is fed back to the refrigerant return line WR2 from the refrigerant supply line WV2, through the refrigerant space 10.10 towards electrode 2 of the plasma arc torch, in the vicinity of the emission insert 2.2, and through the space that is formed by the outer face of the cooling tube 10 on the inner face of electrode 2 of the plasma arc torch.

[0080] In this example, nozzle 4 is cooled indirectly, via nozzle retainer 6, to which the refrigerant is transported through a refrigerant space 6.10 (WV1) and away from which the refrigerant is transported again, via a space of refrigerant 6.11 (WR1). The refrigerant usually flows at a volumetric flow of 1 to 10 l/min. The mouthpiece 4 and the mouthpiece retainer 6 consist of a metal. As a result of the mechanical contact formed with the aid of the external thread 4.20 of the nozzle 4 and the internal thread 6.20 of the nozzle retainer 6, the heat occurring in the nozzle 4 is guided into the nozzle retainer 6, and dissipated by the cooling medium in flow (WV1, WR1).

[0081] The insulating part configured as a plasma gas transport part 3 is formed in one part in this example, and consists of an electrically non-conductive material with good thermal conductivity. As a result of such an insulating part being used, electrical isolation is achieved between electrode 2 of the plasma arc torch and nozzle 4. This is necessary for operation of plasma cutting torch 1, specifically the high voltage collision and the operation of a pilot arc that burns between electrode 2 of the plasma arc torch and nozzle 4. At the same time, heat is conducted between electrode 2 of the plasma arc torch and nozzle 4 from the hottest component to the hottest component. cold, via the insulating part with good thermal conductivity which is configured as a plasma gas carrying part 3. Additional heat exchange thus takes place via the insulating part. The plasma gas transport part 3 is in touch contact with electrode 2 of the plasma arc torch and nozzle 4 via contact faces.

[0082] In this exemplary embodiment, a contact face 2.3 is, for example, a cylindrical outer face of electrode 2 of the plasma arc torch and a contact face 3.5 is a cylindrical inner face of the plasma gas transport part 3. A contact face 3.6 is a cylindrical outer face of the plasma gas transport part 3, and a contact face 4.3 is a cylindrical inner face of the nozzle 4. Preferably, a gap coupling with the small gap, e.g. H7/h6 according to DIN EN ISO 286, between the inner and outer cylindrical faces, is used here in order to perform both obturation in one another and also good contact and thus low thermal resistance and thus good heat transfer. Heat transfer can be improved by applying thermally conductive paste to these contact faces. (Note: even if a thermally conductive paste is used, this is still intended to be covered by the expression “direct contact”). A coupling with a larger clearance, eg H7/g6, can then be used. Furthermore, the nozzle 4 and the plasma gas transport part 3 each have a contact face 4.5 and 3.7, here, these being annular faces, and in touch contact with each other, here. This is a force coupling connection between the annular faces, which is performed by screwing the nozzle 4 into the nozzle retainer 6.

[0083] On account of good thermal conductivity, high temperature differences between nozzle 4 and electrode 2 of plasma arc torch can be avoided, and mechanical stresses on plasma cutting torch 1 that are caused in this way can be reduced.

[0084] A ceramic material, for example, is used here as the electrically non-conductive material with good thermal conductivity. Aluminum nitride, which according to DIN 60672 has very good thermal conductivity (about 180 W/(m*K)) and high electrical resistivity (about 1012 Q*cm), is particularly suitable.

[0085] Figure 2 shows a cylindrical plasma cutting torch 1 in which electrode 2 of the plasma arc torch is cooled directly by the coolant. Indirect cooling, shown in Figure 2, of the nozzle 4, via the nozzle retainer 6, is not provided. Nozzle 4 is cooled by heat conduction via an insulating piece, configured as a plasma gas transport part 3, towards electrode 2 of the plasma arc torch cooled directly by the refrigerant. As a result of such an insulating part being used, electrical isolation between electrode 2 of the plasma arc torch and nozzle 4 is achieved. This is necessary for plasma cutting torch 1 operation, specifically high voltage collision and pilot arc burning operation between plasma arc torch electrode 2 and nozzle 4. At the same time, heat is conducted between the electrode 2 of the plasma arc torch and nozzle 4 from the hottest component to the coldest component, via the insulating part with good thermal conductivity which is configured as a plasma gas transport part 3. Heat exchange Additional additional thus occurs between electrode 2 of the plasma arc torch and nozzle 4, via the plasma gas transport part 3. The plasma gas transport part 3 is in touch contact with the electrode and the nozzle 4, via contact faces.

[0086] In this exemplary embodiment, a contact face 2.3 is, for example, a cylindrical outer face of the electrode 2 of the plasma arc torch, and a contact face 3.5 is a cylindrical inner face of the plasma gas transport part 3 A contact face 3.6 is a cylindrical outer face of the plasma gas transport part 3, and a contact face 4.3 is a cylindrical inner face of the nozzle 4. Preferably a loose coupling with a small clearance, for example , H7/h6, in accordance with DIN EN ISO 286, between the inner and outer cylindrical faces, is used here in order to realize both obturation with each other, and also in contact and, thus, low thermal resistance and thus, good heat transfer. Heat transfer can be improved by applying thermally conductive faces to these contact faces. A coupling with a larger clearance, eg H7/g6, can then be used. Furthermore, the nozzle 4 and the plasma gas transport part 3 each have a contact face 4.5 and 3.7, respectively, here, these being annular faces and in touch with each other, here. This is a force coupling connection between the annular faces, which is made by screwing the nozzle 4 into the nozzle retainer 6.

[0087] The omission of indirect cooling for nozzle 4 results in considerable simplification of the structure of plasma cutting torch 1, as the coolant spaces in nozzle retainer 6 that are otherwise required to transport the refrigerant to its area of action and away again, are dispensed. The electrode is cooled as in figure 1.

[0088] Figure 3 shows a plasma cutting torch 1 in which a nozzle 4 is cooled indirectly, via a nozzle retainer 6, to which the coolant is conveyed through a 6.10 coolant space (WV1) and away from which the refrigerant is transported again, via a 6.11 refrigerant space (WR1). Direct cooling, shown in figures 1 and 2, of electrode 2 of the plasma arc torch, is not provided. Thermal conduction from electrode 2 of the plasma arc torch to nozzle 4 takes place via an insulating piece, configured as a plasma gas carrying part 3, with respect to the indirectly cooled refrigerant nozzle 4. In this particular, the statements made with respect to figures 1 and 2 apply.

[0089] This results in a considerable simplification of the structure of plasma torch 1 and electrode 2 of the plasma arc torch, as the cooling tube 10 and the coolant spaces 2.10 and 10.10, shown in figures 1 and 2, which are otherwise needed in order to transport the coolant to its area of action (WV2) and away again (WR2), are dispensed.

[0090] The plasma cutting torch 1 illustrated in figure 4 differs from the plasma cutting torch illustrated in figure 1, in that the nozzle 4 is directly cooled by a coolant. For this purpose, the nozzle 4 is secured by a nozzle cap 5. An internal thread 5.20 of the nozzle cap 5 is screwed together with an external thread 6.21 of a nozzle retainer 6. The outer face of the nozzle 4 and a part of the nozzle retainer 6, and also the inner face of nozzle cap 5 forms a coolant space 4.10 through which the coolant, which flows to its area of action (WV1) and back again (WR1) through the coolant spaces 6.10 and 6.11 on the mouthpiece retainer 6.

[0091] Arranged between the nozzle 4 and an electrode 2 of the plasma arc torch is an insulating piece configured as a plasma gas transport part 3. In this way, the same advantages are achieved as explained in conjunction with figure 1 Heat is transferred between electrode 2 of the plasma arc torch and nozzle 4 from the hottest component to the coldest component via the insulating part with good thermal conductivity which is configured as a plasma gas transport part 3. Plasma gas transport part 3 is in touch contact with electrode 2 of plasma arc torch and nozzle 4. Thus, mechanical stresses on plasma cutting torch 1 that are provided by large temperature differences can be reduced.

[0092] An advantage compared to the plasma cutting torch shown in figure 1 is that the directly cooled coolant nozzle 4 is cooled better than the indirectly cooled nozzle. Since the coolant in this arrangement flows directly into the vicinity of the nozzle tip and a nozzle hole 4.1, where the greatest nozzle heating occurs, the cooling effect is particularly greater. The coolant space is sealed by O-rings between nozzle cap 5 and nozzle 4, between nozzle cap 5 and nozzle retainer 6, and between nozzle 4 and nozzle retainer 6.

[0093] The nozzle cap 5 is also cooled by the coolant flowing through the coolant space 4.10, which is formed by the outer face of the nozzle 4, and the inner face of the nozzle cap 5. The nozzle cap 5 is heated mainly by radiation from the arc, or plasma jet, and the heated operating part.

[0094] However, the structure of the plasma cutting torch 1 is more complicated, as a nozzle cap 5 is additionally required. A liquid, in the simplest case water, is preferably used as the coolant here.

[0095] Figure 5 shows a plasma cutting torch 1 which is similar to the plasma cutting torch in figure 1, but in which a protective nozzle cap 8 is additionally disposed outside of nozzle 4. Holes 4.1 in nozzle 4 and 8.1 on the nozzle guard cap 8 are located on a center line M. The inner faces of the nozzle guard cap 8 and a nozzle guard retainer 9 form, with the outer faces of the nozzle guard 4 and the nozzle retainer 6 , spaces 8.10 and 9.10 through which a secondary gas SG flows. This secondary gas exits the hole in the protective cap of the 8.1 nozzle, and encloses the plasma jet (not shown), and ensures a defined atmosphere around the latter. In addition, the secondary gas SG protects the nozzle 4 and the protective cap of the nozzle 8 from arcs that may form between them and the operating part. These are referred to as double arcs and can result in damage to the nozzle 4. In particular, when piercing the operating part, the nozzle 4 and the protective cap of the nozzle 8 are highly stressed by splashing hot molten material. The secondary gas SG, the volumetric flow of which can be increased during drilling compared to the value during cutting, keeps material from spilling out of the nozzle 4 and the protective cap of the nozzle 8 and thereby protects them from damage.

[0096] For cooling electrode 2 of plasma arc torch and nozzle 4, the statements made regarding plasma cutting torch 1 according to figure 1 apply. In principle, direct cooling of only electrode 2 of the plasma arc torch - as shown in figure 2 - and indirect cooling of only nozzle 4 - as shown in figure 3 - are also possible in a plasma cutting torch 1 with gas secondary. Statements made with respect to these also apply.

[0097] In the case of plasma cutting torch 1 shown in figure 5, in addition to electrode 2 of plasma arc torch and nozzle 4, the protective cap of nozzle 8 also has to be cooled. The protective cap of the nozzle 8 is heated, in particular, by radiation from the arc or plasma jet and the heated operating part. In particular, when drilling the operating part, the protective cap of the nozzle 8 is highly thermally stressed and heated by splashing red-hot material, and has to be cooled. Therefore, materials with good thermal conductivity and good electrical conductivity, usually metals, e.g. silver, copper, aluminum, tin, zinc, iron, alloyed steel or a metal alloy (e.g. brass) in which these metals are contained individually, or in a total amount of at least 50%, are used.

[0098] Secondary gas SG first of all flows through the plasma cutting torch 1, before it passes through a first space 9.10 which is formed by the inner faces of the nozzle guard retainer 9 and the nozzle guard cap 8 , and the outer faces of the nozzle retainer 6 and the nozzle 4. The first space 9.10 is also connected by an insulating piece, configured as a secondary gas transport part 7, which is located between the nozzle 4 and the protective cap of the nozzle 8. The secondary gas transport part 7 can be formed in a multipart manner.

[0099] Located in the secondary gas transport part 7 are holes 7.1. However, these can also be openings, slots or cuts through which the secondary gas SG flows. By means of a corresponding arrangement of holes 7.1, for example arranged radially with a radial offset and/or an inclination with respect to the centerline M, the secondary gas can be set in rotation. This is to stabilize the arc or plasma jet.

[00100] After it has passed through the secondary gas transport part 7, the secondary gas flows into an interior space 8.10 which is formed by the inner face of the protective cap of the nozzle 8 and the outer face of the nozzle 4, and then , comes out of hole 8.1 in the protective cap of the nozzle 8. With the burning of the arc or the plasma jet, the secondary gas impinges on the latter and can influence them.

[00101] The protective cap of nozzle 8 is usually cooled by SG secondary gas only. Gas cooling has the problem that it is not effective to achieve adequate cooling or heat dissipation, and the volumetric flow of gas required is too high for this proposal. Volumetric gas flows of 5000 to 11 000 l/h are often needed here. At the same time, the volumetric flow of the secondary gas has to be selected such that the best cutting results are achieved. Excessive volumetric flows, which are required for cooling, however, often impair the cutting result.

[00102] In addition, the high gas consumption provided by high volumetric flows is uneconomical. This particularly applies when gases other than air, eg argon, nitrogen, hydrogen, oxygen or helium, are used.

[00103] These problems are remedied by the use of the insulating piece configured as the secondary gas carrying part 7. By the use of such an insulating piece, electrical isolation is achieved between the protective cap of the nozzle 8 and the nozzle 4. In combination with the SG secondary gas, the electrical insulation protects the nozzle 4 and the protective cap of the nozzle 8 from arcs that can form between them and the operating part. These are referred to as double arcs, and can result in damage to nozzle 4 or nozzle protective cover 8.

[00104] At the same time, heat is transferred between the nozzle protective cover 8 and the nozzle 4 from the hottest component to the coldest component, in this case from the nozzle protective cover 8 to the nozzle 4, via the insulating piece with good thermal conductivity which is configured as a secondary gas transport part 7. The secondary gas transport part 7 is in touch contact with the protective cap of the nozzle 8 and the nozzle 4. In this exemplary embodiment, this occurs, via annular faces 8.2 of the protective cap of the nozzle 8 and 7.4 of the secondary gas transport part 7, and the annular faces 7.5 of the secondary gas transport part 7 and 4.4 of the nozzle 4. These are force coupling connections, in which the mouthpiece protective cover 8 with the aid of the mouthpiece protective cover retainer 9 which is screwed by means of an internal thread 9.20 to an external thread 11.20 of a receptacle 11. transport of and secondary gas 7, and this is pressed against the nozzle 4.

[00105] In this way, heat is conducted from the protective cap of the nozzle 8 to the nozzle 4 and thereby cooled. The nozzle 4 in turn is indirectly cooled, as explained in the description of figure 1.

[00106] Figure 6 shows the structure of the plasma cutting torch 1 as in figure 4, but in which a protective nozzle cover 8 is additionally arranged outside the nozzle cover 5.

[00107] Holes 4.1 in Nozzle 4 and 8.1 in Nozzle Protective Cap 8 are located on a centerline M. The inner faces of Nozzle Protective Cap 8 and Nozzle Protective Cap Retainer 9 form, with the outer faces of the mouthpiece cap 5 and the mouthpiece 4, spaces 8.10 and 9.10, respectively, through which a secondary gas SG can flow. This secondary gas exits hole 8.1 in the protective cap of nozzle 8, encloses the plasma jet (not shown), and ensures a defined atmosphere around the latter. In addition, the secondary gas SG protects the nozzle 4, the nozzle cap 5 and the protective cap of the nozzle 8 from arcs that can form between them and the operating part (not shown). These are referred to as double arcs, and can result in damage to the mouthpiece 4, the mouthpiece cap 5, and the mouthpiece cover 8. In particular, when piercing an operating part, the mouthpiece 4, the mouthpiece cap 5 , and the protective cap of the nozzle 8 are highly stressed by splashing hot material. The secondary gas SG, the volumetric flow of which can be increased during drilling compared to the value during cutting, keeps material splashing away from the nozzle 4, the nozzle cap 5 and the protective nozzle cap 8 and thereby protects the same for damage.

[00108] For cooling electrode 2 of plasma arc torch, nozzle 4 and nozzle cover 5, the statements made in the description of figure 4 apply.

[00109] The protective cover of the nozzle 8 is heated, in particular, by radiation from the arc or plasma jet and the heated operating part. In particular, when drilling the operating part, the protective cap of the nozzle 8 is highly thermally stressed and heated by the splashing of red-hot material, and has to be cooled. Therefore, materials with good thermal conductivity and good electrical conductivity, usually metals, for example copper, aluminum, tin, zinc, iron or alloys in which at least one of these metals is contained, are used.

[00110] Secondary gas SG, first of all, flows through plasma torch 1, before it passes through a space 9.10 which is formed by the inner faces of the shield cap retainer 9 and the shield cap 8, and the outer faces of a nozzle retainer 6 and the nozzle cap 5. The space 9.10 is also connected by an insulating piece, configured as a secondary gas transport part 7 for the secondary gas SG, which is located between the cap nozzle 5 and nozzle protective cap 8.

[00111] Located in the secondary gas transport part 7 are holes 7.1. However, these can also be openings, slots or cuts through which the secondary gas SG flows. By means of a corresponding arrangement of these, for example holes 7.1 with a radial offset and/or holes 7.1 arranged radially with an inclination with respect to the centerline M, the secondary gas SG can be set in rotation. This is to stabilize the arc or plasma jet.

[00112] After it has passed through the secondary gas transport part 7, the secondary gas SG flows into the space (inner space) 8.10 which is formed by the inner face of the protective nozzle cap 8, and the outer face of the nozzle cap 5 and nozzle 4, and then exits hole 8.1 in the protective cap of nozzle 8. With the burning of the arc or plasma jet, the secondary gas SG collides with the latter and can influence them.

[00113] The protective cap of nozzle 8 is usually cooled by SG secondary gas only. Gas cooling has the problem that it is not effective in achieving acceptable cooling or heat dissipation, and the volumetric flow of gas required is too high for this proposal. Volumetric gas flows of 5000 to 11 000 l/h are often needed here. At the same time, the volumetric flow of the secondary gas has to be selected such that the best cutting results are achieved. Excessive volumetric flows, which are required for cooling, however, often impair the cutting result. In addition, the high gas consumption provided by high volumetric flows is uneconomical. This particularly applies when gases other than air, eg argon, nitrogen, hydrogen, oxygen, or helium, are used. These problems are remedied by the use of the insulating piece configured as the secondary gas carrying part 7. By the use of such an insulating piece, electrical isolation is achieved between the protective nozzle cap 8 and the nozzle cap 5 and thereby also nozzle 4. In combination with the SG secondary gas, electrical insulation protects nozzle 4, nozzle cap 5 and nozzle protective cap 8 from arcs that can form between them and an operating part (not shown). These are referred to as double arcs, and can result in damage to the mouthpiece, mouthpiece cap, and mouthpiece protective cap.

[00114] At the same time, heat is transferred between the nozzle protective cover 8 and the nozzle cover 5 from the hottest component to the coldest component, in this case from the nozzle protective cover 8 to the nozzle 5, via the insulating part with good thermal conductivity which is configured as a secondary gas transport part 7. The secondary gas transport part 7 is in touch contact with the protective cap of the nozzle 8 and the nozzle cap 5 In this exemplary embodiment, this occurs via annular faces 8.2 of the nozzle protective cap 8 and 7.4 of the secondary gas transport part 7, and the annular faces 7.5 of the secondary gas transport part 7 and 5.3 of the nozzle cap 5. In this example, these are force-coupled connections, in which the protective cap of the mouthpiece 8 is screwed by means of an internal thread 9.20 to an external thread 11.20 of a receptacle 11 with the aid of the protective cover retainer of the mouthpiece 9. mode, this is pressed upwardly against the secondary gas carrying part 7 for the secondary gas SG, and this is pressed against the nozzle cap 5. In this way, heat is conducted from the nozzle protective cap 8 to the nozzle cap 5 and, thus cooled. The mouthpiece cap 5, in turn, is cooled as explained in the description of figure 4.

[00115] Figure 7 shows a plasma cutting torch 1 to which the statements made regarding the embodiment according to figure 6 apply. In addition, the mouthpiece protective cap retainer 9 is screwed through its internal thread 9.20 to an external thread 11.20 of the receptacle 11, which is designated as an insulating piece. Receptacle 11 consists of an electrically non-conductive material with good thermal conductivity. Thereby, heat is transferred to the receptacle 11 from the mouthpiece protective cap retainer 9, which may receive said heat, for example, from the mouthpiece protective cover 8, from a hot operating part, or from radiation. of the arc, via the internal thread 9.20 and the external thread 11.20. The receptacle 11 has refrigerant passages 11.10 and 11.11 for the refrigerant supply line (WV1) and refrigerant return line (WR1), which are here embodied as holes. The coolant flows through the latter and thereby cools the receptacle 11. In this way, the cooling of the mouthpiece protective cap retainer 9 is further improved. Heat is transferred from the nozzle protective cover 8 via the contact face 8.3 thereof, configured as an annular face, to a contact face 9.1, likewise configured as an annular face, on the protective cover retainer of the nozzle 9. The contact faces 8.3 and 9.1 touch each other in a force-coupled manner in this example, in which the protective cap of the nozzle 8 is screwed via the internal thread 9.20 to the external thread 11.20 of the receptacle 11 with the aid of the retainer retainer. nozzle protective cap 9. Thereby, this is pressed upwards against the secondary gas transport part 7, and the nozzle protective cap retainer 9 is pressed against the nozzle protective cap 8. In the present example, the receptacle 11 is made of ceramic. Aluminum nitride, which has very good thermal conductivity (about 180 W/(m*K)) and high electrical resistivity (about 1012 Q*cm), is particularly suitable.

[00116] Refrigerant is simultaneously conveyed to nozzle 4 and nozzle cap 5 through refrigerant space 6.10 and 6.11 in nozzle retainer 6, and cools said nozzle 4 and nozzle cap 5.

[00117] Figure 8 shows an embodiment of a plasma torch 1 which is similar to the embodiment in figure 7. Thus, the statements made regarding the embodiment according to figures 6 and 7 also apply in principle. However, it contains a different embodiment of the insulating piece embodied as a receptacle 11 for the mouthpiece protective cap retainer 9. The receptacle 11 consists of two parts in this example, in which an outer part 11.1 consists of an electrically non-conductive material with good thermal conductivity, and an inner part 11.2 consists of a material with good electrical conductivity and good thermal conductivity.

[00118] The mouthpiece cover retainer 9 is screwed through its internal thread 9.20 to the external thread 11.20 of part 11.1 of receptacle 11.

[00119] Electrically non-conductive material with good thermal conductivity is produced from ceramic, for example aluminum nitride, which has good thermal conductivity (about 180 W/(m*K)) and high electrical resistivity, about 1012 Q*cm The material with good electrical conductivity and good thermal conductivity is, in this case, a metal, e.g. copper, aluminum, tin, zinc, alloyed steel, or alloys (e.g. brass) in which at least one of these metals is contained.

[00120] Generally, it is advantageous for material with good electrical conductivity and good thermal conductivity to have a thermal conductivity of at least 40 W/(m*K)Q, and an electrical resistivity of at most 0.01 Q*cm. In particular, provision can be made here for material with good electrical conductivity and good thermal conductivity to have a thermal conductivity of at least 60 W/(m*K), better still at least 90 W/(m*K) , and preferably 120 W/(m*K). Even more preferably, the material with good electrical conductivity and good thermal conductivity has a thermal conductivity of at least 150 W/(m*K), better still at least 200 W/(m*K), and preferably at least minus 300 W/(m*K). Alternatively or in addition, provision may be made for the material with good electrical conductivity and good thermal conductivity to be a metal, e.g. silver, copper, aluminum, tin, zinc, iron, alloy steel, or a metal alloy (e.g. , brass) in which these metals are contained individually, or in a total amount of at least 50%.

[00121] The use of two different materials has the advantage that, for the complicated part where different formations are required, e.g. holes, cuts, grooves, different openings, etc., the material that can be machined more easily and more cost effective, can be used. In this exemplary embodiment, this is a metal that can be machined more easily than ceramic. Both parts (11.1 and 11.2) are connected together in touch contact in a force coupling manner by being pressed together, with the result that good heat transfer between the cylindrical contact faces 11.5 and 11.6 of the two parts 11.1 and 11.2 is reached. The part 11.2 of the receptacle 11 has refrigerant passages 11.10 and 11.11 for the refrigerant supply line (WV1) and the refrigerant return line (WR1), these being embodied here as holes. The refrigerant flows through the latter and thus carries out its cooling action.

[00122] As can be seen from Figure 8 and the associated description, the present invention also relates to an insulating part for a plasma torch, in particular a plasma cutting torch, for electrical isolation between at least two electrically plasma torch, in which said insulating part consists of at least two parts, in which one part consists of an electrically non-conductive material with good thermal conductivity, and the other or one of the parts consists of a material with good thermal conductivity. electrical conductivity and good thermal conductivity.

[00123] Figure 9 shows a further embodiment of a plasma cutting torch 1 according to the present invention which is similar in principle to the embodiment shown in figure 8. with figures 6, 7 and 8 also apply. However, a different embodiment variant of the insulating piece embodied as a receptacle 11 for the mouthpiece protective cap retainer 9 is shown. The receptacle 11 consists of two parts, in which, in this case, the outer part 11.1, in contrast to the embodiment shown in figure 8, consists of a material with good electrical conductivity and good thermal conductivity (e.g. metal), and the inner part 11.2 consists of an electrically non-conductive material with good thermal conductivity (eg ceramic).

[00124] The mouthpiece cover retainer 9 is screwed through its internal thread 9.20 to the external thread 11.20 of part 11.1 of receptacle 11.

[00125] In this embodiment, the advantage is that the external thread can be introduced into the metal material, which is used for the 11.1 part, and not the ceramic, which is more difficult to machine.

[00126] Figures 10 to 13 show (additionally) different embodiments of an insulating piece configured as a plasma gas transport part 3 for PG plasma gas, it being possible to implement said embodiments in a plasma torch 1, as is shown in Figures 1 to 9, in which each figure with the letter "a" shows a longitudinal section, and each figure with the letter "b" shows a partially sectional side view.

[00127] The plasma gas transport part 3 shown in figures 10a and 10b is produced from an electrically non-conductive material with good thermal conductivity, for example ceramic in this case. Aluminum nitride, which has very good thermal conductivity (about 180 W/(m*K)) and high electrical resistivity (about 1012 Q*cm), is particularly suitable. The associated advantages when used in a plasma cutting torch 1, for example, better cooling, reduction in mechanical stresses, simpler structure, have already been mentioned and explained above in the description of figures 1 to 4.

[00128] Located in the plasma gas transport part 3 are radially arranged holes 3.1 which can be, for example, radially spaced apart and/or radially inclined with respect to the centerline M, and cause a PG plasma gas to rotate on the plasma cutting torch. When plasma gas carrying part 3 has been seated on plasma cutting torch 1, its contact face 3.6 (cylindrical outer face here, for example) is in touch contact with contact face 4.3 (cylindrical inner face here , for example) of nozzle 4, its contact face 3.5 (cylindrical inner face here, for example) is in touch contact with contact face 2.3 (cylindrical external face here, for example) of electrode 2 of the plasma arc torch , and its contact face 3.7 (annular face here, for example) is in touch contact with the contact face 4.5 (annular face here, for example) of nozzle 4 (figures 1 to 9). On the contact face 3.6, there are grooves 3.8. These guide the PG plasma gas to holes 3.1 before it is transported by the latter into an interior space 4.2 in nozzle 4, where electrode 2 of the plasma arc torch is arranged.

[00129] Figures 11a and 11b show a plasma gas transport part 3 consisting of two parts. A first part 3.2 consists of an electrically non-conductive material with good thermal conductivity, while a second part 3.3 consists of a material with good electrical conductivity and good thermal conductivity.

[00130] For part 3.2 of plasma gas transport part 3, use is made here, for example, of ceramic, again, for example, aluminum nitride, which has very good thermal conductivity (about 180 W/( m*K)), and high electrical resistivity (1012 Q*cm). For part 3.3 of the secondary gas transport part 3, use is made here of a metal, e.g. silver, copper, aluminum, tin, zinc, iron, alloyed steel, or a metal alloy (e.g. brass) wherein these metals are contained individually, or in a total amount of at least 50%.

[00131] If, for example, copper is used for part 3.3, the thermal conductivity of the plasma gas transport part 3 is higher than if it only consists of an electrically non-conductive material with good thermal conductivity, for example , aluminum nitride. Depending on its purity, copper has a higher thermal conductivity (max. about 390 W/(m*K)) than aluminum nitride (about 180 W/(m*K)), which is currently considered to be one of the best thermally conductive materials that did not simultaneously have good electrical conductivity. However, there is also aluminum nitride with a thermal conductivity of 220 W/(m*K).

[00132] Because of the better thermal conductivity, this results in even better heat exchange between the nozzle 4 and electrode 2 of the plasma arc torch of the plasma cutting torch 1, according to figures 1 to 9.

[00133] In the simplest case, parts 3.2 and 3.3 are connected together by contact faces 3.21 and 3.31 being pushed together.

[00134] Parts 3.2 and 3.3 may also be connected in a force-coupled manner by means of the contacting faces pressed against opposite joints 3.20 and 3.30, 3.21 and 3.31, and 3.22 and 3.32. Contact faces 3.20, 3.21 and 3.22 are part 3.2 contact faces, and contact faces 3.30, 3.31 and 3.32 are part 3.3 contact faces. Cylindrically configured contact faces 3.31 (cylindrical outer face of part 3.3) and 3.21 (cylindrical inner face of part 3.2) form a coupling connection by force by being pressed together. In this case, a DIN EN ISO 286 interference coupling (eg H7/n6; H7/m6) is used between the cylindrical inner and outer faces.

[00135] It is also possible to connect the two parts (3.2 and 3.3) together by means of form coupling, by welding and/or by adhesive bonding, and/or by means of a thermal method.

[00136] Since the mechanical machining of the ceramic material is usually more difficult than that of a metal, the machining complexity drops. Here, for example, six holes 3.1 have been introduced into the metal part 3.3, said holes having a radial offset a1 and being equidistantly distributed at an angle α1 around the circumference of the plasma gas duct. Very different formations, eg grooves, cuts, holes, etc., are also easier to produce when they are introduced into the metal.

[00137] Figures 12a and 12b show a plasma gas transport part 3 consisting of two parts, in which a first part 3.2 consists of an electrically non-conductive material with good thermal conductivity, while a second part 3.3 consists of an electrically non-conductive material and a thermally non-conductive material.

[00138] For part 3.2 of plasma gas transport part 3, use is made here, for example, of ceramic, again, for example, aluminum nitride, which has very good thermal conductivity (about 180 W/( m*K)), and high electrical resistivity (1012 Q*cm). For part 3.3 of the plasma gas transport part 3, use can be made, for example, of a plastic material, e.g. PEEK, PTFE (polytetrafluoroethylene), Torlon, polyamide-imide (PAI), polyimide ( PI), which has high temperature stability (at least 200°C), and high electrical resistivity (at least 106, even better at least 1010 Q*cm).

[00139] In the simplest case, parts 3.2 and 3.3 are connected together by contact faces 3.21 and 3.31 being pushed over each other. They may also be connected in a force-coupled manner by means of the oppositely pressed together touching contact faces 3.20 and 3.30, 3.21 and 3.31, and 3.22 and 3.32. The cylindrically configured contact faces 3.31 (cylindrical outer face of part 3.3) and 3.21 (cylindrical inner face of part 3.2) then form the coupling connection by force by being pressed together. In this case, a DIN EN ISO 286 interference coupling (eg H7/n6; H7/m6) is used between the cylindrical inner and outer faces. It is also possible to connect the two parts (3.2 and 3.3) together by means of a form coupling and/or an adhesive bond.

[00140] Since the mechanical machining of the ceramic material is usually more difficult than that of a plastic material, the machining complexity drops. Here, for example, six holes 3.1 have been introduced into the plastic part 3.3, said holes having a radial offset a1 and being equidistantly distributed at an angle α1 around the circumference of the gas duct. Very different formations, eg grooves, cuts, holes etc., are also easier to produce when they are introduced into the plastic material.

[00141] Figures 13a and 13b show a plasma gas transport part 3 as in figure 12, except that an additional part 3.4, which consists of a material with the same properties as part 3.3, belongs to the gas transport part 3.4. plasma gas 3.

[00142] Parts 3.2 and 3.4 can be connected together in the same way as parts 3.2 and 3.3, in which contact faces 3.23 and 3.43, 3.24 and 3.44, and 3.25 and 3.25 are connected.

[00143] Since mechanical machining of ceramic material is usually more difficult than that of a plastic material, machining complexity drops, and very different formations, e.g. cuts, holes, etc., are also easier to produce when they are introduced into the plastic material.

[00144] Figures 14a to 14b show a further embodiment of a plasma gas transport part 3. Figures 14c and 14d show a part 3.3 of the plasma gas transport part 3. In this case, figures 14a and 14c show a longitudinal section, and figures 14b and 14d show a partially sectional side view.

[00145] A part 3.2 consists of an electrically non-conductive material with good thermal conductivity, while a part 3.3 consists of an electrically non-conductive material and a thermally non-conductive material.

[00146] Located in part 3.3 of the plasma gas transport part 3 are radially arranged openings, in this case holes 3.1, which can be radially spaced and/or radially inclined with respect to the centerline M, and through which a PG plasma gas flows when the plasma gas transport part 3 has been seated in the plasma cutting torch 1 (see figures 1 to 9).

[00147] Part 3.3 has radially arranged holes 3.9 which are larger than holes 3.1. Inserted into these holes are six 3.2 parts which are illustrated here, for example, as round pins. These are distributed equidistantly around the circumference at an angle that results between the midpoint lines M3.9, of α3=60°.

[00148] When the plasma gas transport part 3 was seated on the plasma cutting torch 1, according to figures 1 to 9, the contact faces 3.61 (outer faces) of the parts 3.2 (round pins) are in contact contact face 4.3 (a cylindrical inner face here) of nozzle 4 and contact faces 3.51 (inner faces) of parts 3.2 (round pins) are in touch contact with contact face 2.3 (a cylindrical outer face) here) of electrode 2 of the plasma arc torch.

[00149] Parts 3.2 have a diameter d3 and a length l3 that is at least as large as half the difference between the diameters d10 and d20 of part 3.3. It is even better when the length l3 is slightly longer in order to secure contact between the contact faces of the round pins 3.2 and the nozzle 4 and electrode 2 of the plasma arc torch. It is also advantageous for the surface of contact faces 3.61 and 3.51 not to be planar, but to be adapted to the cylindrical outer face (contact face 2.3) of electrode 2 of the plasma arc torch and the cylindrical inner face (contact face 4.3) of the plasma arc torch. nozzle 4, such that a shape coupling is produced.

[00150] On contact face 3.6, there are grooves 3.8. These guide the PG plasma gas to holes 3.1 before it is transported by the latter into an interior space 4.2 in nozzle 4, where electrode 2 of the plasma arc torch is disposed.

[00151] Since mechanical machining of ceramic material is usually more difficult than that of a plastic material, machining complexity drops, and very difficult formations, e.g. grooves, cuts, holes, etc., are also easier to make. produce when they are introduced into the plastic material. In this way, despite the use of identical round pins, very different gas pipelines can be produced in a cost-effective manner.

[00152] Furthermore, by changing the number or diameter of the round pins 3.2, different thermal resistances or thermal conductivities of the plasma gas transport part 3 are achievable.

[00153] If the diameter and/or the number of round pins is/are reduced, the thermal resistance increases, and the thermal conductivity drops.

[00154] Since very different thermal loads occur on the nozzle 4 and electrode 2 of the plasma arc torch, depending on the power from 500 W to 200 kW to be implemented in the plasma torch, or plasma cutting torch, it is advantageous to adapt the thermal resistance. In this way, for example, manufacturing costs are reduced when few holes have to be introduced and few round pins have to be used.

[00155] Figures 15 to 17 show (additionally) different embodiments of an insulating piece configured as a secondary gas transport part 7 for a secondary gas SG, it being possible to implement said embodiments in a plasma cutting torch 1, as shown in shown in Figures 6 to 9, in which each figure with the letter "a" shows a partial sectional plan view, and each figure with the letter "b" shows a sectional side view.

[00156] Figures 15a and 15b show a secondary gas transport part 7 for a secondary gas SG as may be used in a plasma cutting torch according to figures 6 to 9.

[00157] The secondary gas transport part 7 shown in figures 15a and 15b consists of an electrically non-conductive material with good thermal conductivity, for example ceramic in this case. Aluminum nitride, which has good thermal conductivity (about 180 W/(m*K)), and high electrical resistivity (about 1012 Q*cm), is particularly suitable here again. As a result of the low thermal resistance and high thermal conductivity, large temperature differences can be avoided and mechanical stresses on the plasma cutting torch that are caused thereby can be reduced.

[00158] Located in the secondary gas transport part 7 are radially arranged holes 7.1 which can also be radially or radially spaced apart and/or radially inclined with respect to the centerline M, and through which the secondary gas SG can flow or flow when the secondary gas carrying part 7 has been seated in the plasma cutting torch 1. In this example, 12 holes are radially spaced apart by a dimension a11, and are distributed equidistantly around the circumference, in which the angle which is enclosed by the points mean holes is denoted α11. However, there are also openings, slots or cuts through which the secondary gas SG flows when the secondary gas carrying part 7 has been seated in the plasma cutting torch 1. The secondary gas carrying part 7 has two annular contact faces 7.4 and 7.5.

[00159] By the use of this secondary gas carrying part 7, electrical isolation is achieved between the protective nozzle cap 8 and the nozzle cap 5 and thereby also the nozzle 4 of the plasma cutting torch 1 illustrated in the figures 6 to 9. In combination with secondary gas, electrical insulation protects nozzle 4, nozzle cap 5 and nozzle protective cap 8 from arcing between them, and the operating part (not shown). These are referred to as double arcs, and can result in damage to nozzle 4, nozzle cap 5, and nozzle protective cap 8.

[00160] At the same time, heat is transferred between the nozzle protective cover 8 and the nozzle cover 5 from the hottest component to the coldest component, in this case from the nozzle protective cover 8 to the nozzle 5, via the insulating part with good thermal conductivity which is configured as a secondary gas transport part 7. The secondary gas transport part 7 is in touch contact with the protective cap of the nozzle 8 and the nozzle cap 5 In this exemplary embodiment, this occurs via annular faces 8.2 of the protective nozzle cap 8 and 7.4 of the secondary gas transport part 7 and annular faces 7.5 of the secondary gas transport part 7 and 5.3 of the nozzle cap 5, which touch, as illustrated in figures 6 to 9.

[00161] Figures 16a and 16b likewise show a secondary gas transport part 7 for a secondary gas SG, which consists of two parts. A first part 7.2 consists of an electrically non-conductive material with good thermal conductivity, while a second part 7.3 consists of a material with good electrical conductivity and good thermal conductivity.

[00162] For part 7.2 of the secondary gas transport part 7, use is made here, for example, of ceramic, again, for example, aluminum nitride, which has very good thermal conductivity (about 180 W/(m) *K)), and high electrical resistivity (about 1012 Q*cm). For part 7.3 of the secondary gas transport part 7, use is made here of a metal, e.g. silver, copper, aluminum, tin, zinc, iron, alloyed steel, or a metal alloy (e.g. brass) wherein these metals are contained individually, or in a total amount of at least 50%.

[00163] If, for example, copper is used for part 7.3, the thermal conductivity of the secondary gas transport part 7 is higher than if it only consists of electrically non-conductive material with good thermal conductivity, for example, nitride aluminum. Depending on its purity, copper has higher thermal conductivity (max about 390 W/(m*K)) than aluminum nitride (about 180 W/(m*K)), which is currently considered to be a of the best thermally conducted materials that did not simultaneously have good electrical conductivity. Because of the better conductivity, this results in even better heat exchange between the protective shield cap 8 and the shield cap 5 of the plasma cutting torch 1, as shown in figures 6 to 9.

[00164] In the simplest case, parts 7.2 and 7.3 are connected together by contact faces 7.21 and 7.31 being pushed over each other.

[00165] Parts 7.2 and 7.3 may also be connected in a force-coupled manner by means of contact faces pressed together oppositely and touching contact faces 7.20 and 7.30, 7.21 and 7.31, and 7.22 and 7.32. Contact faces 7.20, 7.21 and 7.22 are part 7.2 contact faces, and contact faces 7.30, 7.31 and 7.32 are part 7.3 contact faces. Cylindrically configured contact faces 7.31 (cylindrical outer face of part 7.3) and 7.21 (cylindrical inner face of part 7.2) form a coupling connection by force by being pressed together. In this case, a DIN EN ISO 286 interference coupling (eg H7/n6; H/m6) is used between the cylindrical inner and outer faces.

[00166] It is also possible to connect the two parts together by form coupling, by welding, and/or by adhesive bonding.

[00167] Since the mechanical machining of the ceramic material is usually more difficult than that of a metal, the machining complexity drops. Here, for example, twelve holes 7.1 have been introduced into the metal part 7.3, said holes having a radial offset a11, and being equidistantly distributed at an angle α11 around the circumference of the gas duct. Very different formations, eg grooves, cuts, holes, etc., are also easier to produce when they are driven into metal.

[00168] Figures 17a and 17b likewise show a secondary gas transport part 7 for a secondary gas SG, which consists of two parts. In contrast to the embodiment according to figure 16, a first part 7.2 here consists of a material with good electrical conductivity and good thermal conductivity, and a second part 7.3 consists of an electrically non-conductive material with good thermal conductivity. Otherwise, the same remarks as made with respect to figures 16a and 6b apply.

[00169] Figures 18a, 18b, 18c and 18d show a further embodiment of a secondary gas transport part 7 for a secondary gas SG, which can be used in a plasma cutting torch according to figures 6 to 9 .

[00170] Figure 18a shows a plan view, and figures 18b and 18c show sectional side views of different embodiments thereof. Figure 18d shows a part 7.3, consisting of electrically non-conductive material and thermally non-conductive material, of the secondary gas transport part 7.

[00171] Located in part 7.3 of the secondary gas transport part 7 are radially arranged holes 7.1 which can also be radially or radially spaced apart and/or radially inclined with respect to the centerline M, and through which the secondary gas SG can flow when the secondary gas carrying part 7 has been seated in the plasma cutting torch 1. In this example, twelve holes are radially spaced apart by a dimension a11, and are distributed equidistantly around the circumference, at which the angle which is enclosed by the midpoints of the holes is denoted α11 (eg 30° here). However, there are also openings, slots or cuts through which the secondary gas SG flows when the secondary gas carrying part 7 has been seated in the plasma cutting torch 1 (see, in this connection, for example, figures 6 to 9).

[00172] Figure 18d shows that, in this example, part 7.3 has twelve additional axially arranged holes 7.9 that are larger than the holes or openings 7.1.

[00173] In figures 18a and 18b, twelve parts 7.2, which are illustrated here, for example, as round pins, have been inserted into these holes 7.9. Round pins 7.2 consist of electrically non-conductive material with good thermal conductivity, while part 7.3 consists of electrically non-conductive material and thermally non-conductive material.

[00174] When the secondary gas carrying part 7 was seated in the plasma cutting torch 1, according to figures 6 to 9, the contact faces 7.51 of the round pins 7.2 are in touch contact with a contact face 5.3 (annular face here, for example) of the mouthpiece cover, 5 and the contact faces 7.41 of the round pins 7.2 are in touch contact with a contact face 8.2 (annular face here, for example) of the protective cover of the mouthpiece ( figures 6 to 9).

[00175] Part 7.2 has a diameter d7 and a length l7 which is at least as large as the width b of part 7.3. It is even better when the length l7 is slightly longer so as to obtain secure contact between the contact faces of the round pins 7.2 and the nozzle cap 5 and the protective cap of the nozzle 8.

[00176] Figure 18c shows another embodiment of the secondary gas transport part 7 for secondary gas. In this case, two parts 7.2 and 7.6 indicated as round pins, for example, were inserted into each hole 7.9. Part 7.3 consists of an electrically non-conductive material and a thermally non-conductive material, the round pegs 7.2 consist of an electrically non-conductive material with good thermal conductivity, and the round pegs 7.6 consist of a material with good electrical conductivity and good thermal conductivity.

[00177] When the secondary gas carrying part 7 was seated in the plasma cutting torch 1, according to figures 6 to 9, the contact faces 7.51 of the round pins 7.2 are in touch contact with a contact face 5.3 (annular face here, for example) of the nozzle cover 5, and the contact faces 7.41 of the round pins 7.6 are in touch contact with a contact face 8.2 (annular face here, for example) of the protective cover of the nozzle 8 (see also figures 6 to 9). Both round pins 7.2 and 7.6 are connected by their contact faces 7.42 and 7.52 touching each other.

[00178] Parts 7.2 have a diameter of d7 and a length of l71. In this example, parts 7.6 have the same diameter and a length of l72, where the sum of the lengths l71 and l72 is at least as large as the width b of part 7.3. It is even better when the sum of the lengths is slightly greater, e.g. greater than 0.1 mm, so as to obtain secure contact between the contact faces 7.51 of the round pins 7.2 and the mouthpiece cover 5, and the contact 7.41 of the round pins 7.6 and the protective cap of the nozzle 8.

[00179] Figure 18c and the associated description shown in the present invention thus also relate in a generalized way to an insulating part for a plasma torch, in particular a plasma cutting torch, for electrical isolation between at at least two electrically conductive components of the plasma torch, in which the insulating part consists of at least three parts, in which one of the parts consists of an electrically non-conductive material with good thermal conductivity, another of the parts consists of an electrically non-conductive material -conductive, and thermally non-conductive material, and the additional part, or an additional one of the parts, consists of a material with good electrical conductivity and good thermal conductivity.

[00180] The secondary gas transport parts 7 shown in figures 15 to 18 can also be used in a plasma cutting torch 1 according to figure 5. Here, by using this secondary gas transport part 7, insulation electrical insulation is achieved between nozzle protective cover 8 and nozzle 4. In combination with the SG secondary gas, electrical insulation protects nozzle 4 and nozzle protective cover 8 from arcs that can form between them, and a piece of operation. These are referred to as double arcs, and can result in damage to nozzle 4 and nozzle protective cover 8.

[00181] At the same time, heat is transferred between the nozzle protective cover 8 and the nozzle 4 from the hottest component to the coldest component, in this case from the nozzle protective cover 8 to the nozzle 4, via the insulating part with good thermal conductivity which is configured as a secondary gas transport part 7. The secondary gas transport part 7 is in touch contact with the protective cap of the nozzle 8 and the nozzle 4. For the exemplary embodiments of the secondary gas transport part 7 which are shown in figures 15, 16 and 17, this occurs via the contact annular faces 8.2 of the nozzle protective cover 8, and the contact annular faces 7.4 of the secondary gas transport part 7 , and the annular contact faces 7.5 of the secondary gas transport part 7, and the annular contact faces 4.4 of the nozzle 4, which, as shown in figure 5, touch each other.

[00182] In the exemplary embodiments, the secondary gas transport part 7 shown in figures 18b and 18c, heat transfer takes place via the annular contact face 8.2 of the protective cap of the nozzle 8, and the contact faces 7.41 of the round pins 7.2 or 7.6 of the secondary gas carrying part 7 and 7.51 of the round pins 7.2 by touching the contact face 4.4 (the annular face, for example here) of the nozzle 4, as illustrated in figure 5.

[00183] Figures 19a to 19d show sectional illustrations of arrangements of a nozzle 4 and a secondary gas transport part 7 for a secondary gas SG, in accordance with particular embodiments of the invention in Figures 15 to 18. The statements given with in relation to figure 5 and figures 15 to 18 apply here.

[00184] In this case, figure 19a shows an arrangement with a secondary gas transport part 7, according to figures 15a and 15b, figure 19b shows an arrangement with a secondary gas transport part, according to the figures 16a and 16b , figure 19c shows an arrangement with a secondary gas transport part according to figures 17a and 17b , and figure 19d shows an arrangement with a secondary gas transport part according to figure 18a and figure 18b.

[00185] In these exemplary embodiments, the secondary gas transport part 7 can be connected to the nozzle 4, in the simplest case, by being pushed over the other. They may also be connected in a shape-coupled and force-coupled manner, or by adhesive bonding, however. When metal/metal and/or metal/ceramic is used at the point of connection, welding is also possible as a connection.

[00186] Figures 20a to 20d show sectional illustrations of arrangements of a mouthpiece cap 5 and a secondary gas transport part 7 for a secondary gas SG, in accordance with Figures 15 to 18, in accordance with particular embodiments of the invention. The statements given with respect to figures 6 to 9 and figures 15 to 18 apply here.

[00187] In this case, figure 20a shows an arrangement with a secondary gas transport part, according to figures 15a and 15b; figure 20b shows an arrangement with a secondary gas transport part, according to figures 16a and 16b; figure 20c shows an arrangement with a secondary gas transport part according to figures 17a and 17b , and figure 20d shows an arrangement with a secondary gas transport part according to figures 18a to 18d .

[00188] In these exemplary embodiments, the secondary gas transport part 7 can be connected to the mouthpiece cap 5, in the simplest case, by being pushed over the other. They may also be connected in a shape-coupled and force-coupled manner, or by adhesive bonding, however. When metal/metal and/or metal/ceramic is used at the point of connection, soldering is also possible as a connection.

[00189] Figures 21a to 21d show sectional illustrations of arrangements of a protective nozzle cap 8 and a secondary gas transport part 7 for the secondary gas SG, in accordance with Figures 15 to 18. The statements given regarding figures 5 to 9 and figures 15 to 18 apply here.

[00190] In this case, the figure Fig. 21a shows an arrangement with a secondary gas transport part according to figures 15a and 15b; figure 21b shows an arrangement with a secondary gas transport part according to figures 16a and 16b; figure 21c shows an arrangement with a secondary gas transport part according to figures 17a and 17b , and figure 21d shows an arrangement with a secondary gas transport part according to figures Fig. 18a to 18d.

[00191] In these exemplary embodiments, the secondary gas transport part 7 can be connected to the protective cap of the mouthpiece 8 in the simplest case by being pushed over the other. They may also be connected in a shape-coupled and force-coupled manner, or by adhesive bonding, however. When metal/metal and/or metal/ceramic is used at the point of connection, welding is also possible as a connection.

[00192] Figures 22a and 22b show arrangements of an electrode 2 of the plasma arc torch and a plasma gas transport part 3 for a PG plasma gas, according to figures 11 to 13, according to particular embodiments of the invention.

[00193] In this case, figure 22a shows an arrangement with a plasma gas transport part according to figure 11a and figure 11b, and figure 22b shows an arrangement with a plasma gas transport part according to figure 13a and figure 13b.

[00194] In this exemplary embodiment, a contact face 2.3 is, for example, a cylindrical outer face of the electrode 2 of the plasma arc torch, and a contact face 3.5 is a cylindrical inner face of the plasma gas transport part 3 Preferably, a gap coupling with a small gap, for example H7/h6, in accordance with DIN EN ISO 286, between the inner and outer cylindrical faces, is used here in order to effect both obturation to each other, and also good contact and thus low thermal resistance and thus good heat transfer. Heat transfer can be improved by applying thermally conductive paste to these contact faces. A coupling with a larger clearance, eg H7/g6, can then be used.

[00195] It is also possible to use an interference coupling between the plasma gas transport part 3 and electrode 2 of the plasma arc torch. This optimizes heat transfer, naturally. However, this has the consequence that electrode 2 of plasma arc torch and plasma gas transport part 3 can only be replaced together in plasma cutting torch 1.

[00196] Figure 23 shows an arrangement of an electrode 2 of the plasma arc torch and a plasma gas transport part 3 for a PG plasma gas, according to a particular embodiment of the present invention.

[00197] In this arrangement, contact faces 3.51 of round pins 3.2 of plasma gas transport part 3 are in touch contact with a contact face 2.3 (cylindrical outer face, for example, here) of electrode 2 of the torch plasma arc (also see figures 1 to 9).

[00198] Parts 3.2 have a diameter d3 and a length l3 that is at least as large as half the difference between the diameters d10 and d20 of part 3.3. It is even better when the length l3 is slightly longer in order to secure contact between the contact faces of the round pins 3.2 and the nozzle 4 and electrode 2 of the plasma arc torch. It is also advantageous for the surface of contact faces 3.61 and 3.51 not to be planar, but to be adapted to the cylindrical outer face (contact face 2.3) of electrode 2 of the plasma arc torch, and the cylindrical inner face (contact face 4.3). ) of the nozzle, such that a shape coupling is produced.

[00199] Arrangements consisting of wear parts and the insulating part, or the gas carrying part, are listed by way of example only. Other combinations, for example nozzle and gas transport part, are also possible, of course.

[00200] Where reference has been made to coolant or the like in the above description, a cooling medium is very generally intended to be so significant.

[00201] Arrangements and full plasma torches, among others, are described in the description above. This is without telling a person skilled in the art that the invention may also consist of sub-combinations and individual parts, for example components or wear parts. Therefore, protection is also explicitly claimed for these.

[00202] Finally, new definitions that are intended apply to the full description above:

[00203] “Good electrical conductivity” is intended to mean that the electrical resistivity is at most 0.01 Q*cm.

[00204] "Electrically non-conductive" is intended to mean that the resistivity is at least 106 Q*cm, better yet at least 1010 Q*cm, and/or that the electrical resistance is at least 7 kV/mm, better yet at least 10 kV/mm.

[00205] “Good thermal conductivity” is intended to mean that the thermal conductivity is at least 40 W/(m*K), better still at least 60 W/(m*K), even better still at least 90 W/(m *K).

[00206] “Good thermal conductivity” is intended to mean that the thermal conductivity is at least 120 W/(m*K), better still at least 150 W/(m*K), even better still at least 180 W/(m*K) *K).

[00207] Finally, "good thermal conductivity" particularly for metals is understood to mean that the thermal conductivity is at least 200 W/(m*K), better still at least 300 W/(m*K).

[00208] The features of the invention which are disclosed in the above description, drawing and claims may be essential both individually and in any desired combinations in order to carry out the invention in its various embodiments. LIST OF REFERENCE SIGNS 1 Plasma cutting torch 2 Electrode 2.1 Electrode retainer 2.2 Emission insert 2.3 Contact face 2.10 Refrigerant space 3 Plasma gas transport part 3.1 Bore 3.2 Part 3.3 Part 3.4 Part 3.5 Contact face 3.6 Contact face 3.7 Contact face 3.8 Groove 3.9 Hole 3.20 Contact face 3.21 Contact face 3.22 Contact face 3.23 Contact face 3.24 Contact face 3.25 Contact face 3.30 Contact face 3.31 Contact face 3.32 Contact face 3.43 Contact face contact 3.44 Contact face 3.45 Contact face 3.51 Contact face 3.61 Contact face 4 Nozzle 4.1 Nozzle bore 4.2 Interior space 4.3 Contact face 4.4 Contact face 4.5 Contact face 4.10 Coolant space 4.20 External thread 5 Nozzle cap 5.1 Nozzle bore cap 5.3 Contact face 5.20 Inner thread 6 Nozzle retainer 6.10 Refrigerant space 6.11 Refrigerant space 6.20 Inner thread 6.21 Outer thread 7 Dry gas transport part 7.1 Hole 7.2 Part 7.3 Part 7.4 Contact face 7.5 Contact face 7.6 Part 7.9 Holes 7.20 Contact face 7.21 Contact face 7.22 Contact face 7.30 Contact face 7.31 Contact face 7.32 Contact face 7.41 Contact face 7.42 Contact face contact 7.51 Contact face 7.52 Contact face 8 Nozzle protective cover 8.1 Nozzle hole protective cover 8.2 Contact face 8.3 Contact face 8.10 Interior space 8.11 Interior space 9 Nozzle protective cover retainer 9.1 Contact face 9.10 Interior space 9.20 Internal thread 10 Coolant tube 10.1 Refrigerant space 11 Receptacle 11.1 Part 11.2 Part 11.5 Contact face 11.6 Contact face 11.10 Refrigerant passage 11.11 Refrigerant passage 11.20 External thread PG Plasma gas SG Secondary gas WR1 Refrigerant return line 1 WR2 Coolant return line 2 WV1 Coolant supply line 1 WV2 Coolant supply line 2 a1 Radial deviation a11 Radial deviation b Width d3 Diameter d7 Diameter d10 Outside Diameter d11 Inside Diameter d15 Diameter d20 Inside Diameter d21 Outside Diameter d25 Diameter d30 Inside Diameter d31 Outside Diameter d60 Outside Diameter l3 Length l31 Length l32 Length l7 Length l71 Length 171 Line Length 173. M3.1 Centerline M3.2 Centerline M3.9 Centerline M7.1 Centerline M3.6 Centerline α1 Angle α3 Angle α7 Angle α11 Angle

Claims (24)

1. Insulating part of a multi-part plasma arc torch for electrical isolation between at least two electrically conductive components of a plasma torch, characterized in that it comprises at least two parts (3.2, 3.3; 7.2, 7.3; 11.1, 11.2), in which one of the parts (3.2; 7.2; 11.1) consists of an electrically non-conductive and heat-conducting material and the other or at least one other of the parts (3.3; 7.3; 11.2) consists of an electrically non-conductive material. -conductive and non-heat-conductive, the electrically non-conductive and heat-conducting material having a thermal conductivity of at least 40 W/(m*K). 2. Insulating part of a plasma arc torch, according to claim 21, characterized in that the part (3.2) consisting of an electrically non-conductive and heat-conducting material has at least one surface that functions as a contact face (3.51, 3.61, 7.41, 7.51), in alignment with and projecting e-do beyond an immediately adjacent surface of the part (3.3, 7.3) consisting of an electrically non-conductive and non-conductive material of heat. 3. Insulating part of a plasma arc torch for electrical isolation between at least two electrically conductive components of a plasma torch characterized in that it consists of at least two parts (3.2, 3.3; 7.2, 7.3), in which one of the parts (3.3; 7.3) consists of an electrically conductive and heat-conducting material and the other (3.2; 7.2) or at least one other of the parts consists of an electrically non-conductive and heat-conducting material, the electrically conductive material and heat conductor has a thermal conductivity of at least 40 W/(m*K) a specific electrical resistivity of at most 0.01 Q*cm and that the electrically non-conductive and heat conducting material has a thermal conductivity of at least 40 W/(m*K). 4. Insulating part of a plasma arc torch for electrical isolation between at least two electrically conductive components of a plasma torch, characterized in that it consists of at least three parts (7.2, 7.3, 7.6), in which one of the parts (7.6) consists of an electrically conductive and heat-conducting material, another of the parts (7.2) of an electrically non-conductive and heat-conducting material and another of the parts (7.3) consists of an electrically non-conductive and non-conductive material. heat conductor, the electrically conductive and heat-conducting material having a thermal conductivity of at least 40 W/(m*K) and electrical resistivity of at most 0.01 Q * cm and the electrically non-conductive material and heat conductor has a thermal conductivity of at least 40 W/(m*K). 5. Insulating part of a plasma arc torch according to any one of claims 1, 3 or 4, characterized in that the thermal conductivity is preferably at least 60 W/(m*K), more preferably of at least 90 W/(m*K), even more preferably of at least 120 W/(m*K), even more preferably of at least 150 W/(m*K), and even more preferably of most preferred form of at least 180 W/(m*K), 6. Insulating part for a plasma arc torch, according to any one of the preceding claims, characterized in that the electrically non-conductive and heat-conducting material and/or the electrically non-conductive and non-heat-conducting material have an electrical resistivity of at least 106 Q*cm, preferably at least 1010 Q*cm, and/or an electrical resistance of at least 7 kV/mm, preferably at least 10 kV/mm. 7. Insulating part for a plasma arc torch, according to any one of the preceding claims, characterized in that the electrically non-conductive and conductive material is a ceramic, preferably from the group of nitride ceramics, in particular, aluminum nitride ceramics, boron nitride ceramics, and silicon nitride ceramics, the carbide ceramics, in particular, silicon carbide ceramics, the oxide ceramics, in particular, aluminum oxide ceramics, zirconia oxide ceramics, and beryllium oxide ceramics, and silicate ceramics, or is a plastic material, eg plastic film. 8. Insulating part for a plasma arc torch, according to any one of the preceding claims, characterized in that the electrically non-conductive and non-heat-conducting material has a thermal conductivity of at most 1 W/(m*K) . 9. Insulating part for a plasma arc torch, according to any one of the preceding claims, characterized in that the parts are connected together in a form coupling, force coupling, or cohesive manner, and/or by adhesive bonding , or by a thermal method, for example brazing or soldering. 10. Insulating part for a plasma arc torch, according to any one of the preceding claims, characterized in that it has at least one opening. 11. Insulating part for a plasma arc torch, according to any one of the preceding claims, characterized in that it has a recess or at least one groove (3.8) configured to conduct a gas, in particular a plasma gas, secondary gas, or cooling gas. 12. Arrangement comprising a plasma arc torch electrode (2) and/or a plasma arc torch nozzle (4), or a plasma arc torch nozzle cover (5), and/or a protective a plasma arc torch nozzle (8), or a retainer of a protective cap of a plasma arc torch nozzle (9), characterized in that it comprises an insulating part of a plasma arc torch as defined in any one of the preceding claims . 13. Arrangement according to claim 12, characterized in that the insulating part of the plasma arc torch is in direct contact with the electrode (2) of the plasma arc torch, and/or with said nozzle (4) , and/or with said mouthpiece cap (5), and/or with said mouthpiece protective cap (8), and/or with said mouthpiece protective cap retainer (9). 14. Arrangement comprising a receptacle (11) for a shield cap retainer for the nozzle (9), and a protective shield cap retainer (9) for a plasma torch, in particular a plasma cutting torch (1), characterized in that the receptacle (11) is configured as an insulating piece as defined in any one of claims 1 to 11. 15. Arrangement consisting of an electrode for a plasma arc torch (2) and a nozzle for a plasma torch (4), characterized in that between the electrode of the plasma arc torch (2) and the nozzle of the torch arc torch (4) there is arranged an insulating part for a plasma arc torch as defined in any one of claims 1 to 11 configured as a plasma gas conducting part (3). 16. Arrangement comprising a nozzle for a plasma arc torch (4) and a protective cap for the nozzle for a plasma arc torch (8) characterized in that an insulating part as defined in any one of claims 1 to 11 configured as a secondary gas transport part (7) is arranged between said nozzle (4) and said nozzle protective cap (8), 17. Arrangement comprising a nozzle cap for a plasma arc torch (5) and a protective nozzle cap for a plasma torch (8), characterized in that an insulating part for a plasma arc torch as defined in any one of claims 1 to 11 is configured as a secondary gas carrying part (7) is arranged between the mouthpiece cap (5) and the mouthpiece protective cap (8). 18. Plasma torch, in particular, a plasma cutting torch (1), characterized in that it comprises at least one insulating part for a plasma arc torch as defined in any one of claims 1 to 11. 19. Plasma torch according to claim 18, characterized in that the insulating part for a plasma arc torch or a part thereof consisting of an electrically non-conductive and heat-conducting material has at least one surface, preferably two surfaces, functioning as a contact face, said surface being in direct contact with at least one surface of an electrically conductive component in which the electrically conductive material has a specific electrical resistivity of at most 0.01Q* cm. 20. Plasma torch according to any one of claims 18 and or 19, characterized in that the insulating part for a plasma arc torch is a gas conduction part. 21. Plasma torch, according to any one of claims 18 to 20, characterized in that said insulating part has at least one surface that is in direct contact with a cooling medium. 22. Plasma torch, in particular, a plasma cutting torch (1), characterized in that it comprises at least one arrangement as defined in any one of claims 12 to 17. A method for machining an operating part with a thermal plasma or for plasma cutting, or for plasma welding, characterized by employing a plasma torch as defined in any one of claims 18 to 22. 24. Method according to claim 23, characterized in that a laser beam from a laser is coupled to the plasma torch in addition to the plasma jet, in particular, in which the laser is a fiber laser, a diode laser, and/or a diode-pumped laser.

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